Ah yes, my favourite non-military engineer, building non-autonomous, IR guided, non-loitering munitions / non-cruise missile / non-air-intercept drone / non-autonomous recon platform. Jesus at this point you are just building next gen autonomous drone. Also i belive that you have exact ideas what can be put into that free space.
WTF are you talking about? He is building stuff that is already in service with the US military, he is literally copying others ideas so poorly that he is failing hard when the info to do this is already out there.
I’ve been designing and building competitive RC planes for a couple years in SAE aero and here is my brain dump: 1. Thrust needs to be increased, EDFs are not known for their static/low speed thrust, especially those small ones. Make sure you have an adequate thrust to weight ratio. Decreasing takeoff weight is crucial since your wing area is a design constraint. Increase powertrain battery voltage if you can, you’ll have to sacrifice capacity to save weight though. 2. Use an analysis tool like XFLR5 instead of ecalc, it uses actual airfoil data and VLM to solve for lift, drag, and moment along CG. See how much lift you’re making at takeoff speeds near stall angle. Check CG also, it might be unstable (especially on launch 3) 3. Increase aft control surface size, they look pretty small and won’t do much at low speeds. The EDF should help, but looking at the video it’s not enough. The planes longitudinal inertia seems really high especially with the heavy batteries up front and large fuselage. 4. I believe you are close to/a little unstable in yaw because you don’t recover very fast at 13:11. You have almost equal stabilizing and destabilizing side area on the fuselage and the control surfaces don’t seem to help with that since they’re moving to control pitch and roll. Increase your aft side area, this will help you recover from a large sideslip which seems to be the biggest issue on takeoff at lower speeds. At a 90 degree sideslip on the 3rd attempt the plane seemed like it had no intention of recovering from it. This could be done by adding fixed fins that are not your control surfaces. You will also dutch roll during these thrown takeoffs if you dont have yaw damping. 5. Add ailerons because you have little roll authority at lower speeds. Roll authority increases if your control surfaces are further outward- those in the back aren’t gonna do much if you have a large lateral inertia from the wings, but this all depends on how heavy the wings are. Your plane rolled a lot during these takeoffs and didn’t seem to want to recover. Dihedral won’t solve this problem. Include a flap too for higher lift during takeoff. If you have any questions I’d be happy to answer in the reply comments or if you have a discord.
didnt know sae had a drone competition. I am the aero composite lead in my school's formula sae team. would have joined the drone one if my school had it
Imo I would agree with kyle points but I would give a try using some kind of launcher which would give much more speed at takeoff as first step just to make it launchable.
WTF are you talking about? He is building stuff that is already in service with the US military, he is literally copying others ideas so poorly that he is failing hard when the info to do this is already out there.
Correct me if I'm wrong, but Hatchet is meant to be initially launched via rocket with the EDF just keeping it in the air. As such, redesigning it to be hand-launched seems like a step in the wrong direction. I think a catapult is a better idea, as it can provide the higher launch speeds that are needed without having to deal with the complexities of rocket launches.
Or a magnetic linear rail launch system like Tom Stanton and others have built before. Smooth, consistent acceleration. Though that doesn't help the whole cruise missile vibe!
Given that he has never flown a radio control plane before this would be a step in the right direction. Slower flying means more forgiving and easier to launch/test. Once he can make the hand launch version work, then he can work on increasing the wing loading and going faster/autonomous
As someone who builds a lot of RC planes, I’d recommend adding ailerons, and possibly flaps, to improve lift and control at lower speeds during takeoffs and landings. As you mentioned, the plane seems too heavy relative to the available thrust-using lightweight filaments would help a lot. Also, it’s unlikely you’ll be able to manually stabilize the plane quickly enough during takeoffs and landings, so I highly recommend adding a flight controller for automatic stabilization. Finally, it looks like the elevator authority might not be sufficient with just the vectored thrust setup. All that said, this plane looks absolutely stunning, and I can’t wait to see what you do with v2!
I don't know too much about this field but would it not be extremely hard to add control surfaces as well as the servos to control them when the end goal is for them to fold?
@@smellyboars4865 flaps would be a pain (and probably needed it if the wings are just bigger) but ailerons could added without too much extra complication... especially considering how complicated everything else on this is
Yes, it definitely needs ailerons, it has negative stability in the roll plane. A single micro servo would do that quite easily and cheaply. A rail/catapult launcher would certainly make getting it airborne a lot more consistent, and could be adjusted to give more/less speed on launch.
I disagree on the additional control surfaces, at least initially. Adding lightness is priority number 1, and ailerons aren’t really necessary when roll control can be carried out through X-.taik mixing. I’d instead move the wing up.
@@howlingwolven The X tail doesn't have enough of a control moment (force x distance) to be effective at low speed, maybe at Mach 1, but not at launch speeds. A micro servo is only about 2 grams in weight. Moving the wings up would certainly help.
Definitely reduce takeoff weight at least for early test flights. A rail launcher would be a game changer for getting you off the ground consistently with enough velocity to get enough lift out of the small wings. In addition, a rail launch would let you spin up your edf right before you launch. That way you are taking full advantage of your vectored thrust right as you leave the rail, when your control surfaces are going to really struggle giving you enough control authority.
ERAU Grad, changing the air frame before getting it airborne is going to kill his understanding of how it flies in its ideal flight configuration. He should be focused on getting it airborne first then worry about changing it IMO. Slingshot launch could help him dial in his v speeds without needing to redesign his aircraft.
1. Take off weight is too large, well, at least for the wing area you have chosen which is pretty much fixed if they are going to fold out of the fuselage eventually. 2. CG and wing placement seem to be mismatched, dangle it on a string from the mean chord, quarter chord point as a sanity check. 3. Control surfaces are too small for realistically any control during takeoff, and the fact you do not have ailerons would mean that they would need increasing in size compared to a normal set. For roll control matching ref area isn't sufficient as the moments are what counts, that close to the fuselage the moment will be tiny. 4. I'm unsure about the thrust vectoring, there is so much vorticity coming from that ducted fan that redirecting that flow is probably doing nothing apart from obstructing it, which leads me to the final point.. 5. I don't think there is any thrust being made tbh. Compare just holding the plane at full throttle to what the fan is expected to produce. Really cool project, I hope you can make it fly!
Pretty good points, I was also going to point out the thrust vectoring and thrust issues, I feel that the thrust vectoring needs to be eliminated, and the inlet needs a big redesign to let a lot more are in and directing it accordingly, I would provably go with an all around inlet or 4 inlets similar to that of a cruise missile, but nonetheless it needs a lot of air going in just because its fan propulsion, there is no pressure differential created by combustion and the air needs to enter as easily as it can, that design could hinder the air flow.
My thoughts exactly aswell, i'd argue that he could make it a biplan to double the wing area but even that may not be enough, and comes with additional drawbacks.
Yes point 5 seemed almost obvious, but I could be mistaken. With enough trust I would expect it to at least fly a few meters even with all the other points being an issue as well. I would've expected a thrust test inside. :)
13:15 the way your friend is throwing it here is forcing the plane to pitch up. If he can hold it at COM and guide it into the air under the planes own power, you’ll be able to keep control. Alternatively maybe a rail like the V1 can help you eliminate variables here. Looking forward to seeing more!
No, no he can't. There isn't enough power and way too much weight. There is more than enough info out there that this dude should have figured this out before he failed like this.
Put it on a vertical test stand and measure thrust. I don't think you have NEARLY enough. It should be able to take off from your unlucky friend's hand.
You should try a bungee launch. It is much faster and more predictable than a hand launch, especially with a new plane. Also before you risk your complex delicate powered drone, I suggest you create a simple unpowered model from a cardboard tube that is appropriately weighted and winged to perform the same as the real thing and try launching that as a glider. If it wont glide, at least a little then adjust things until it does.
A couple thoughts I had (although I don't do a lot of hobby drone stuff, I do work in aerospace) 1. 3d printed parts are probably not great for takeoff weight. It makes sense to use them for the aero surfaces where you need complex shapes, but you could probably cut down on their use in other places. The ball turret in particular strikes me as something that adds a lot of weight for something that still can't get a stable launch. Until you can get the prototype to reliably launch, maybe replace that and use a mass simulator to figure out what your mass budget for that payload is. 2. The inlet for the ducted fan looks like it's going to induce a pitch up moment that will vary with thrust, if possible, try replacing that with symmetric inlets so that you have more balanced aero forces. Also, having the inlet along the body like that makes me worry about losing thrust in high AoA situations, but at low speed, that's probably not as much of an issue. 3. I like the design of the control surfaces connected to thrust vector control vanes, but I worry about your proposed Y-tail idea. Non-symmetrical external control surfaces coupled to symmetrical internal control surfaces are going to require some complex control laws.
Some thoughts: 1. Are Center of lift/Center of gravity at the right spot? 2. Is the air inlet sufficient enough to generate enough thrust? Look at pictures of older Tomahawk cruise missiles. They had some kind of duct sticking out below for good air intake. 3. Is the thrust even enough for the over all weight? From the video it seems quite a lot of weight in the front. 4. The steering rudders might be a bit small to give enough directional authority?
I feel like with a set of canards (moveable or not) and a better inlet (or any way to produce more thrust), most of the issues could be fixed but that's just my guess, I'm no expert after all
In thrust we trust bruh. I think those TVC vanes are trashing your thrust. Obviously weight reduction is great but stick a flow meter behind the thing and see what’s up before you go tearing it apart.
Regarding your thoughts: 1. Yeah, your wing loading seems too high, especially considering you don't have highly cambered wings or flaps. You don't share numbers but for reference, a wing loading of 3.5 kg/m^3 will give a flight speed of 20mph at a coefficient of lift of 0.7. Printing your wings out of foaming filament can reduce their weight by like 40%, though you'd also want to incorporate a carbon spar. 2. Larger tail is necessary, but remember it doesn't all have to be all-moving control surfaces. If you want to experiment with stability margin, you could add a passive tail and reduce its size with progressive testing. 3. I agree rail launch with bungee is the safest way to get this thing up.
I am by no means an aerospace engineer, just a hobbyist drone/rc plane pilot. Here are my 2 cents: these first launch attempts look very similar to that I've experienced with my first rc plane (zohd nano talon). The problem with such planes is that they have a relatively high wing loading and are pretty hard to hand launch. I crashed my plane around 20 times before I figured out that you need to give it *much* more kick on the launch. Because of that I decided to bungee launch it. With bungee launcher it took off easily on the first try. My bungee setup consisted of 10 feet of rope attached to 10 feet of elastic band, the part with elastic band is attached to the hook on the ground. The other side with the rope has a loop which is attached to a hook mounted to the airplane. The hook should be mounted on the bottom of fuselage a bit forward of aircraft CG. Thanks for the great video. Best wishes from Ukraine.
I think it needs to pass a glide test before you try powered flight. Make sure you've got the CG far enough forward to be stable and that the tail has enough downward pitch authority to keep the nose up.
I might consider a weighted test article to hash out launch and glide ratio. Same weight layout and construction just without all the electronics. Inherently unstable works for fighter jets but your drone should be able to track mostly straight and glide even a little bit without input. This will also allow you to adjust CG location to determine balanced flight profile.
I wonder, why a swept back wing design? Swept back wings are worse than straight wings as low speed lift goes, also they have less than ideal stall characteristics Also those control surfaces might be still a bit too small but im not sure
Another thing, which airfoil are you using? I'd suggest to calculate a rough Reynolds number you'll be operating at and use an airfoil with a lower efficiency but better stall characteristics at first, then maybe move to a more efficient airfoil
12:30 Looks possibly tails heavy but for sure the thrust isn't enough for hand launch. Ideally you'd want the EDF to almost support the "plane"'s weight. Not sure how much roll control you have, you may want more dihedral especially for Mk. I.
This is amazing dude. You casually made a Shahed-101. Looks like you learned why they use rocket assist take off. You also need a propeller about 3 times this size.
I was thinking rail launcher when your buddy was chucking it. I really think you need tail wings. Those 4 X-patten, or even 2 larger Y-pattern stabilizers, are not enough. I think you need the 2 larger Y-pattern rudders and 2 normal rear wings, then you'll home free. Stall and launch speeds will be much better. Some kind of carbon landing sliders might also be good. At least it when you are finally landing it, it will not risk tearing up the bottom. That's my 2 cents.
i am certain this man builds a missile and then sits and thinks for like 30 minutes about how to make it seem like its for amateur rocketry(i would do the same)
also: i would make it a stealthier cross section and put the inlet on the top.....ermmm i mean make it a lifting body and put the inlet on top to avoid FOD
Honestly, with that endoframe- skip the intake duct and let the edf breathe, just open frame it without the intake. While the intake might be fine at speed, all of the airflow at takeoff is coming from the fan/ vacuum cleaner lol.
Ooh I like this idea. In air deployment sounds cool. Although, given the use case which he outlined, it should still have the ability to hover at a constant altitude to track the rocket launch, so achieving stability at low speed is of paramount importance. But wait, how does he plan to hover again with TVC EDF firing at the rear and fixed wing?
i'll add some of my rc plane design experience here since i am also in the middle of designing a 3d printed edf plane. i ran into some very similar problems with my first designs. now i can't tell you specifically why it doesn't work because that can be a number of things. but overall to me it seems like this may be worth thinking about: - weight. like you already said you should probably reduce the takeoff weight. i agree. i learned quickly that building light first and not second is a big factor in what works and what doesn't. you have quite a lot of equipment on board. and you also chose some rather dense filament. from what i've seen you want to have about at least 70-80% as much thrust as weight. at least at this scale. more is always better. i had some prototypes closer to 50%. those flew. but only in ground effect. and going into a turn would always lead to a crash. getting a more powerful EDF and or a higher voltage battery could help here but this usualyl also increases the weight. - EDF aerodynamics. thrust verctoring is a cool idea. but here it may work against you. the TVC setup causes a rather significant disturbance in the airflow behind the EDF and probably creates a lot of drag and turbulence. which isn't ideal for thrust. in my models i learned that you get the highest thrust by having a very smooth EDF exhaust tube with geometry that starts with the diameter of the EDF and then becomes slightly thinner towards the end. something around 20% lower diameter. i also saw some very strong control effects from control surfaces like you have used at low speeds so the TVC may also just not be needed here. if the entire fin moves that has a larger effect than one might think. i was surprised by my own models. - filament slection. you mentioned you used PET-G. for rc planes this is not ideal if you want to build light. me and a lot of others use a filament type known as LW-PLA. i get mine from colorfabb. this filament can be printed with an extrusion multiplier of around 50% so it's about half air by volume. this makes it more like foam and less like plastic but the weight savings are amazing. it is noticeably weaker than other filaments of course so you may have to use some carbon rods for reinforcement. i have a video about how i personally print LW-PLA on my channel (shameless plug). - center of gravity. this is just from how hatchet was behaving when thrown. can be caused by a whole lot of other things but it looks like the CG might just be a little bit too far aft. i usually go with having it near the forward 1/3 of the wing measured at the root. i also sometimes make a glider model to verify the CG. where the model is entirely made out of LW pla and has no electronics installed so it's as light as possible. i then tape some small weight to the front or aft until it glides straight and then measure the CG. i hope some of this can help. i'm excited to see it fly one day.
I love this idea, but there are some improvements I would consider. Firstly, I would use a launch rail because any fluctuation in launch direction is going to make it tumble, along with the high takeoff speed, it seems like the launch rail would help a lot. Secondly, I don't think the 4 fins on the back are a great choice for a horizontally moving aircraft, I would use 3 fins in the back (2 elevons and 1 rudder) and move the ailerons to the wings. Thirdly, I would find another way to mount the edf because it looks like it is barley getting any airflow with the side port. Fourthly, I would get rid of the thrust veins because it just looks like it is limiting thrust even more, and the added control isn't really needed because its not going as fast as a rocket. Fifthly, the round airframe is increasing the required takeoff speed even more, I would make the bottom side a little more flatter. I also want to clarify that I am not an expert and some of the suggestions I made may be incorrect. Also, I want to say that I love your videos and I am very exited to see this project will get completed! ❤
Seconding the need for a launch rail, the hand launches start the drone in a highly unstable condition and it doesn't have the control, speed, or altitude to recover from it.
the tube with winglet design really only works when launched from an airborne platform as its already moving fast enough to generate lift. the motor only has to sustain its speed
I would recommend building a model as similar as possible out of dollar tree foamboard. It is important that you get the CG right, normally about 1/4 chord or slightly forward works great. Testing a foamboard model would allow you to have the lightweight model you need for takeoff and hand launching while also allowing you to gain an understanding where you are lacking in stability. It may not hurt to try and throw your model in XFLR5 without the fuselage and run a stability analysis with your current cg location and such to ensure your model is statically and dynamaically stable. This will also allow you to quickly change your model in software and give you a good place to start with real world testing. I do not recomend sweep for a model like this because it is not going fast enough for it to consider compressible factors. The things I recomended should give you a good starting point and understanding, giving you more time to come up with possibly more thrust for hand launching or bunge launching methods.
The second I saw the first launch attempt, I thought in order: "too heavy" and "hmm maybe a bungee launcher would work. Seems you're on top of things and don't need my input. I'm excited to see what you come up with. My credentials are that I once duct taped a rock to a plane to balance the cg, and it flew great.
@ if you’re speaking about my comment, I think I had an unstable internet connection and so it posted my comment twice. I’ll delete one to eliminate the confusion.
Use a catapult launcher, and check your CG.🤔 It appears to be tail heavy. Lastly, your main wings may be too large. The wing drag could be overwhelming the edf. Either make the edf more powerful or reduce the main wings. My 2.5 cents 🫡
The proportions of this are scale-like, but really bad for RC. If i were you, I'd probably 1)increase the length and wingspan by at least 50% while keeping the dimensions of the fuselage. 2) rail or bungee launch for sure. This thing is HEAVY for its size, you're going to need so much speed 3) move the intake to the top, going to help with FOD Ingestion and a little with lift/pitch stability under thrust at low speeds, especially considering 4) tail feathers. These definitely need to be bigger. Like 3x probably. Without ailerons and no dihedral, your role control is going to be trash. The smallests gusts of wind will have this thing flipping over. The
Make the entire rear fin section magnetically detachable and use pogo pins to provide it power back there. Buy a compound bow and use that to get it up to launch speed; could probably make a stand utilize a garage door sensor to activate the full throttle condition to prevent any false launch events. I would also magnetically attach the wings as well if it remains fixed winged. Probably could add a simple parachute for free fall conditions as well.
I have zero practical experience unfortunately due to lack of time and money but I did do a concept design for my Master's thesis and have some aerospace knowledge so some feedback from me: (Also I don't have much time so pardon me if I talk about something you already mentioned in video) 1. Try building the launch rail or do some figuring out how to hand launch properly. Launch 1 (I think, can't see much) and 2 you basically had a stall angle the moment it left Your friend's hand. I would avoid using the method in Launch 3 (pushing) as it basically asks for inducing a spin. 2. Looks tail heavy. Try moving CG forward or wings back. Now this is model aircraft world but in real world CG is placed in front of centre of lift. The main wing always creates a pitch down torque while the job of rear stabilizer is to create a pitch up torque. Since this is a model aircraft You could just aim to place CG perfectly at centre of lift. 3. Make sure that EDF of Yours is not limited by Your inlet. Hard to tell but looks a too small. EDFs are not compressors, they will struggle if inlet is too small. Ideally, area of cross section of Your inlet (at its smallest point) should be equal to the area the fan blades take. Additionally remember that walls of Your inlet will induce drag on the air coming in further limiting it (to consider when adding different twists and shapes in the inlet) 4. Looks very heavy and these wings look small. You want to minimize the weight as much as possible or increase the size of the wings., or both. Consider using a material like LW-PLA (Light Weight PLA) when 3D printing. It works by foaming when printing and at some cost of structural strength I've seen it able to reduce weight by up to 50% when setup properly. 5. Not sure if You did it but since You are 3D printing the wings You might as well optimize the wing by choosing a right airfoil. Go to airfoiltools.com , use a Raynolds Number Calculator and then use that number in their search options to find the right airfoil maximizing the lift or Cl/Cd while being structurally viable. 6. If You are using these fins alone and no ailerons on the wings then at slow speeds (when launching for example), especially considering the weight of this thing and the inertia in roll axis the wings give it, I would imagine You have zero roll control. Basically only thing giving You roll control at that point are the tiny fins behind the EDF. At slow speeds Your exterior fins do nothing and thrust vectoring does not impact roll axis. 7. And keep in mind the torque that EDF is introducing on Your roll axis, especially when launching at full power. These things can pack a punch. 8. To help with roll stability problem I would try introducing some dihedral to the wings. These are the points that came into my mind seeing the design and launches. I love Your channel and Your projects! And I fully expect to see this full idea (totally not cruise missile) flying! Even if it takes few simpler iterations first! Keep up the good work!
I agree with the bungie launch /rail idea. You have to have sufficient air flow to activate that Bernoulli's type stuff, Haha! The device never gets close to positively breaching stall speed. You already know this. I'm just thinking out loud here! I enjoyed your vid. I'm here for the first time. AMAZING & fun journey young man!
I see two big problems. The thrust from your impeller is too low. Not only because it is a fairly inexpensive impeller but also because electrical impellers build up little static pressure in the impeller and the diameter behind the impeller is smaller than the impeller itself. I also think your center of gravity is too far back. For further experiments I would get away from the the thrustvector, use a better impeller and first build a traditional aircrafttail with larger control surfaces, in order to have a better chance of being able to handle any strange flight characteristics better. Of course, a lighter aircraft always helps and could be successful when paird with a stronger impeller. If you want to achieve a good result, please only trust well-known manufacturers when it comes to thrust Statements. Hope that helps.😊
You think his center of gravity is too far back when it was nose diving into the ground... really? You think you are helping? Your nonsense about "impellers" is even worse.
ERAU Grad here... I wouldn't change your aircraft, I would change your launch mechanism. You're going to have negative transfer of learning (about how your system handles) by changing the aircraft. You need more air speed to get enough lift for that thing... Maybe consider a slingshot launcher on rails? Part of me also doesn't think that edf can propel that aircraft to give it the maneuverability you're looking for, but since I don't know those specs, that's a blind guess.
Some of my thoughts for moving forward with Hatchet. 1. Reduce weight - among your good ideas where to reduce, maybe try to lower your number of 3d prints, or optimize their weight with design or other filaments like foamy LW PLA. 2. Rail launching - great idea for repeatability and accuracy of launching, also you can test lot of variables like optimal angle, speed etc before going for vertical launching with booster 3. Change the intake to the upside - you will have much less trouble with testing and landing. With fixed wing version it is very fast change, with folding wings it can force the orientation change on the wingtips (basically turning the wingbox upsidedown) 4. Ailerons for the fixed wing version - i think you have small control authority with control surfaces on the body for small speeds. Maybe it is not a bad idea to introduce ailerons on the fixed wing. It should give a lot of lever for roll stabilization. You can decide to not use them during flight to learn more about your fins/tvc control system. You can also move them closer and closer to the body with each Hatchet refinement, until you ditch them alltogether with introduction of folding wings. This should be easy to implement with the creation of lighter/simplier wingbox you are thinking. I wish you luck, this is great channel and you have briliant concepts of thinking. Mark
I don't think the drone has the thrust necessary for its weight, but I also believe that instead of throwing it like a paper plane you should accompany it by jogging a bit before letting it go with a smoother transition.
Catapult launch systems (giant rubber band) are normal for these types of high wing loading designs with ducted fans. The available trust is generally subpar until you have some speed behind it to feed the fan. This also provides enough air over the wings to provide lift. Your stabilization also appears lacking in authority which is not allowing it to track straight, which in turn is upending whatever lift is available.
@@eriknulty6392 No, if the system is so screwed that you can't hand launch it then he probably isn't going to be able to hand fly it either. And spamming the same comment over and over again doesn't make it a better idea.
@@thomgizziz thats where you are wrong, that heavy bird with tiny control surfaces will fly great (AT HIGH SPEEDS). but going 4 mph you may as well just throw a brick. I do know a thing or 3 about building and flying scale planes, been doing it for 25+ years. but at that curb weight it wont fly until MIN. 20mph and thats probably even still pushing stall speed. she is a 50+ bird.
I have some experience in hand launching RC planes. When I just started the biggest mistake I made (and I can see you make it as well) was to through the plane upwards. This makes the plane immediately stall. Even though it is counter intuitive you should through the plane slightly downwards (to a imaginary point about 10 meters or 30 feet in front of you) this way the plane will have enough speed to fly or it will just land without (or the least amount of) damage.
I love your use of common techniques like 3D printing and common motors to build things like this, its really unique and most things like this are behind military walls
Ottimo lavoro complimenti 👍👍👍👍😉😉 Secondo il mio parere da aeromodellista, la ventola ha poca trazione. Il convogliatore dell' aria messo sotto , favorisce una cabrata verso l' alto del drone , e quindi lo porta in stallo subito. La velocità di lancio è troppo bassa per creare portanza e per dare autorità alle parti mobili in fase di lancio. La miscelazione delle parti mobili, in questa configurazione andrebbe bene se si usa il drone come razzo, ma non come aereo. Queste sono mie opinioni, naturalmente non voglio insegnarti nulla, ma hai fatto un gran lavoro che mi ha interessato molto. Mi sono iscritto al tuo canale , mi interessa molto lo sviluppo del tuo drone, continua cosi. like..👍👍👍👍✌✌
instead of a turbine fan, i recommend using a centrifugal fan and having a hollow in the base which stores the fan folded up, then a small linear converter pushes the propeller out and when it starts spinning, it unfold and propels the aircraft with more power, and you wont have to implement active vectoring which increases throttle drag by alot
Thrust too low, too heavy, not enough tail stabilizer authority (too small). I think you are focusing too much on making it look cool as opposed to flying well. For example why ducted fan? Why thrust vectoring? Why 3D printing instead of other construction methods which are stronger and lighter? That stuff is heavy and obviously not helping it fly better. A better way to do this would be to start with a commercial RC airplane that flies well, then modify it to add your payload to it. It flies well and the payload functions? Great, now you can make modifications to the airframe to see if it improves performance. The key is to make small changes and test the result of that. While testing airframe stuff you can have a dummy weight instead of the actual payload because as you're finding out, there will be crashes. Quick and dirty is the name of the game for prototypes. If it looks good you're wasting time and therefore iterating slower than you could be. It's tempting to have an idea in our head of what the final product will look like and just go right to that. It's much better to be constantly thinking of the objective and be open to anything and everything that gets you closer to that, regardless if it matches what you initially thought. Ugly stuff that works is better than looks cool but doesn't work. The UA-cam channel rctestflight is a superb example of this type of engineering. I worked as an R&D engineer, now retired and have designed and flown a few RC aircraft. This is my first time seeing your channel and I don't know your background so please don't take offense. Good luck!
Maybe print a Titan Falcon and get a FPV headset cheap plus IR video? No need to innovate when the solution is ready to print 😊 See YT videos, some militaries print them themselves to get cheap surveillance drones
@@TackshooterOG well, the Falcon gives you 300km range. But if you want cooler, how about the VTOL Titan Cobra? I actually just ordered parts for China for that one with FPV googles. Got them real cheap, like 60% off AliExpress since I lived in China and can buy it directly there. Still even with AliExpress parts, it's a damn cool morphing VTOL to Airplane
A proper check for COG/COL seems to be in order as well as calculating the stall speed. The way it "glided" (or how it didn't glide) when thrown seemed to indicate something is seriously off with these factors.
As a college student studying aerospace engineering and apart of a college aircraft design / evaluation team here are some considerations possibly not mentioned. Material choice: because the cardboard tube offers a high level of rigidity don't worry about the internal parts being super strong, 3d printed parts can be small with ribs, if a part is to have a large cavity use low infill or even lightweight "foaming" filament. This will reduce the launch mass without suffering huge losses to internal structures. EDF Inlet: currently as the aircraft is flying the edf is trying to pull air out of the stream of air going around the plane. This is not only inefficient but could also be causing losses of with the tail section. As it currently stands a small bit of air is being pulled in by adhesion to the inlet and negative pressure caused by the fan. A proper inlet for the edf would go a long way especially once at cruising speed. This does not have to be much more than a little scoop that hinges down with the pivot point near where the current inlet stops. Additionally a thin grate could be added to help reduce injested objects and prevent the edf from exploding. The grate does not have to be super large or thick as where it is likely to pick stuff up (the ground) it should not be travelling super fast.
How heavy is that thing? It looks like it weighs about 2x too much to hand launch. EDFs have basically no static thrust so the rail launch idea is definitely a good one but its a lot of time and effort when you need to focus on getting the characteristics of the airframe down first. I'd build a super light one just to test the advanced control system you are using. Maybe a foam board tube with a light 3d printed nose cone combined with moving the wings backward so you can use your existing edf location and power unit. Im biased as foam board is my bread and butter go to material for model planes. Also are you printing the plane out of any foaming light weight materials? I think they have just about everything in a LW version for RC planes nowadays. If you need that payload weight to stay the same you can only take so much weight out of the structure while keeping it in that soze and form factor. If it were me, I would shoot for something about 30% to 50% larger while trying to keep the weight of the structure relatively the same. I would also do a pusher prop on a thrust vectoring base along with ailerons for controls. If you want to keep the wings light and simple canards can handle the roll and add a lot more pitch control. Hope this helps! If you want to have a more in depth conversation let me know. I'll hop on the RC testflight discord.
Aero eng & rc enthusiast here. First of all, dope project. Second of all, I think your solution ideas will work. The issue you have is a result of your tail fins being too small; look into tail volume coefficients to size them. Also, I’m sure you already know this, but CG should be located right abt quarter chord on the main wing or more forward. Further forward it is, higher cruise speed will be. Finally, make sure your TWR is above ~0.5, higher the better. Good luck!
Great job! Your 3D printing skills are top-notch. My little bit of advice is you need about 3 times more thrust. With your current weight, it will be hard to achieve with this diameter housing. Your other option is to slash your weight. As fun and cool as 3D printing is, you may need to use more lightweight building techniques. Now all this advice relies on the fact that you are going to hand throw this aircraft With the rocket assist take off the unit may fly but will have an extremely high stall speed. Personally , I think more power is your best bet. Good luck! 😊
Very cool and ambitious project! Completely new desings are expected to end up in aerodynamics hell so hang in there! You should consider collaboration with another youtuber like Think Flight on this. He has experience designing and building winged drones so he might have some valuable input! In the meantime here are some ideas: 1) Push the center of mass forward, probably a lot. The aerodynamic center doesn't have enough leverage to keep the thing prograde. 2) Add ailerons on the wings for roll: Control authority far from the center of mass is a big yes. 3) I like the bigger top fins idea but a more traditional design might be more in order here for better control separation and whatnot. Rotate the back 45 degrees, add one big rudder fin on top and a bigger set of horizontal fins or even wings that can take over roll as well if big enough (they can also be set upside down for negative lift if you end up pushing the center of mass way forward and it ends up front-heavy). 4) Push or rotate the wings up to get a dihedral effect. Right now is looks like you get the opposite effect which actually gives the drone the tendency to go upside down. Good luck! Subscribing for this!
A few observations: The swept crescent wing is always a bit of a tricky approach, I built a few high speed slope soarers with that planform a few decades ago and they were super sensitive to CG positioning. Looking at your screen shot of the eCalc data, your 'Stabilizier Volume (Vbar)' is 0.16. From the eCalc page: The Stabilizer Volume (Vbar) is a value for manoeuvrability. The lower the more agile the aircraft gets. Typical values are: 0.5...0.9 Trainer 0.3...0.6 Aerobatic 0.5...0.8 Glider 0.5...1.1 High-lift Jet 0.3...0.5 Combat Jet 0.0 for Delta & Flying Wing (due missing Stabilizer) It is possible that your choice of wing aerofoil is creating a nose up pitching moment, and the tail is insufficiently sized to counteract it, quickly/instantly leading to a stall. Also remember that the V-tail will have less authority than a true horizontal stabiliser. So when entering the values for it into eCalc used the projected plan view for span. Perhaps choose a reflexed aerofoil for the wing, it will have a much lower pitching moment, so you can get away with small tail surfaces. Launch speed looks far too slow. As other have said, look at a rail launch, or even something as simple as a bungee/hi-start launch. A lot of scale EDF guys use these to get heavy underpowered jets into the sky safely. Owlplane has a download for a launcher if you're looking for inspiration. It generate 25kg/50+lb of pull. owlplane.gumroad.com/l/tsqpe
@@belliduradespicio8009 Very true. What I meant was that the 'V' of the tail surfaces would result in a much less efficient lift vector, due to being inclined at 45° to the direction it is needed. The resulting component is going to be much less than would be achieved with a proper horizontal stabiliser. A V-tail equipped aircraft often needs 10-15% more surface area than a conventional horizontal-stabiliser equipped aircraft would.
Here are some ideas. 1. As general rule of tumb, place CoM slightly ahead of lift center, it improves stability but decreases controllability. If you put CoM behind, the aircraft is unstable but highly manoeuvrable, which requires good autopilot and thrust.' 2. Rail guide for takeoff. Even a simple rail would make takeoffs easier, plus you could add catapult mechanism to it for increased chances of success" 3. Remove thrust vectoring, it quite often destabilises simpler guidance systems at low speeds. *P.s. i have extremely low IRL experience, most of these thoughts come from the KSP experience and other UA-camrs of .
Some suggestions for your design. 1. Find and use a lightweight filament for this print. 2. Find and use some flight stability software. 3. Refine the inlet for the duct engine. I would add three duct inlets. One on the top and two on the side. 4. Increase the size of the wings to help with lift. 5. Move the wings to the aircraft's top to help with stability. 6. Rework the electronics so the center of gravity is just under the wings. 7. Remove all unnecessary equipment and only put what is needed to fly the drone. 8. Increase the size of your control surfaces. I hope these suggestions help.
To add to the sea of suggestions, you can lose a little bit of tail weight if you switch to two tail servos, with the two remaining surfaces slightly offset from each other longitudinally by a few millimetres; then your thrust vectoring vanes, supported by a carbon fiber tube running through their center, can pass by each other, forming a X-shape overlapping vanes. One (or both for maintaining control authority balance) would have V-notches in the middle (hence the need for the CF tube) to allow for whatever max deflection angle is desired without colliding with each other. By running them through to the opposite sides of the exhaust duct you also gain a greater supporting moment against dynamic pressure exerted on the fins, which could allow you to reduce the structure around the fin mounting points (as well as eliminating the mass of two servos and their wiring).
Couple thoughts based on the RC plane I made years ago now. Most of all, Get Real Flight RC flight sim, with a controller. This will allow you to build your exact aircraft with all the dimensions and similar if not exact parts. I did this so the model had all the same parts, and settings for your receiver and controller. So the servo mixing, throw angles and percents are all the same. I’m willing to bet you’ll get the same exact outcome in the sim. The beauty with that is you can adjust your center of gravity or thrust with no effort. Try to fly again to see what helps. Same with thrust vectoring and control surface iterations. Start with the exact model as built. The. Tweak it to make it flyable the way you want. Changes in CG, CT, thrust ramp speed, weight, all of it. You can test in the sim throwing without thrust. You might find it doesn’t roll. If so, you have a torque issue and need to ramp throttle up and maybe mix with ailerons. Once you have a flyable model, that handles how you like. that will guide you to designs changes you can make to get there. If you enter in everything exact and it flys like crap in the sim. Be prepared to have the same issues IRL. Mine was a push prop designed with a huge brushless motor and prop with heavy pitch. That thing basically nosed in if I just lit up the throttle. As the center of thrust was a good 4 inches above center of gravity. And center of mass really. But at a glide the handling was good. Well, once I figured it how to make it not so tail heavy. My two suggestions for your aircraft would be to lock thrust vectoring for now. Treat it as a glider, as much as you can. So you can see how well it handles without thrust. Then also get a gyro based stability controller. It’ll plug in between the receiver and servos. That can help compensate for some of the behavior like when you throttle up with too high thrust or torque. Or when you start getting into that stall zone.
Lowering the weight and raising airspeed as you said will really help. You can use a flight controller to get some artificial stabilization to help you out. Larger tail feathers will also really help you out. I recommend not investing into Spektrum too much. Get an inexpensive Radiomaster radio and use ELRS. The receivers are much lighter, less expensive, and better range. They are also more compatible with flight controllers.
Same thing happend to me with the edf .Something sucked in and crushed it's blades. Good thing is KT boad protected me .If it didn't I lost my eye that day.Also I think hatchet need more thrust. That EDF isn't enough.
For test launches you can bungee launch or discus launch it if chucking doesn’t work. Saves you from building a launch rail right away. For a bungee launch, a slot in the bottom of the airframe engages a hook on the launch rope which is elastic. Stretch out and let go, and Hatchet will fly off. For the discus method, ensure your wing spar is rigidly installed. Put a finger hook through the wing tip, hold Hatchet on the pads of your index and middle fingers, and spin it around like you’re throwing a discus. You can throw a lot harder that way.
I think the problem is the weight distribution in the body content and enough power for the engine, aerodynamic accuracy etc... but I like it. Don't forget the rear wings they are very small, they are suitable for rocket concepts and not the planes.😅
For hand launching try a wing tip launch. Hold it by the wing and spin and then release. Don't need as much strength that way. I am worried about the lack of control surfaces on the wings making it harder to control at low thrust. Another test is to empty out all the weight and see if you can get it to just glide. I can't wait to see the changes you make to get Hatchet in the air. Best of luck
At the flight attemps your friend seems to be trying to launch/throw the drone off its center of gravity which naturally puts its in an unstable state causing it to stall/drop. I'm no expert on RC planes but I've flown and thrown them enough to know how not to launch a RC Plane/Drone. Always try to throw them FROM their center of gravity or mass. at 13:15 your friend also seems to be thrusting it from the exhaust which gives it an unstable amount of force pushing the center of thrust way back and increasing the AoA of the wings in return causing a stall. Another thing that he seems to be throwing the drone in a curve which should not do; what he should do instead is thrust/throw the drone as straight forward as he can without altering the drones course/orientation. If I weren't able to explain things good enough; please pardon me for my English as it is not my native language :)
While the weight, wing area and low thrust don't help with the hand launches, some better technique might've made it fly at least for a moment. The most consistent way i found for hand launching is by grabbing the fuselage slightly (very) in front of the CG, running as fast as possible while maintaining somewhat constant angle of the plane, and then gently throwing it forward. The way this plane was launched (or rather, thrown) gave it so much angular momentum every time, it probably wouldn't recover even with infinite thrust. Also, running with the plane in hand gives you some feedback on how the lift is, and if the plane is correctly pitched for launching. The runups were very short so there was no way to correct a wrong aoa. Good luck with the next iteration, cant wait.
I think your problem is most likely the tail size. Ultimately you need to counteract the pitching moment of the wing. Traditionally this is done with a tail an elevator. You could use your thrust vectoring to do the same although that will be much more challenging to get right. I’d start with a larger tail to get it flying. Then start shortening the surfaces as you learn to rely more on the thrust vectoring.
Great wildly ambitious project. 2question/suggestions: 1: What is the stall speed? - can your helper throw the vehicle (or anything) to that speed? 2: thrust? From the very limited view it looks like it is frankly insignificant relative to the mass of the vehicle. It is obviously unable to visually accelerate the vehicle in the first 1-2 seconds. Your idea of reducing total mass is good. But I’m thinking you need to maybe triple the thrust! Or how about rocket assistance for 5-10 seconds? Good luck
Rocket rules still apply to planes: center of gravity vs center of pressure is incredibly important. That huge wing has moved your center of pressure WAY forward, and those itty-bitty fins just cannot compete with them at hand-launch speeds to provide any realistic stability. Rockets can keep CG comparatively aft, only slightly forward of the fins, but on airplanes the CG is often around 1/4 to 1/3rd from the leading edge of the wing, for almost exactly the same reasons. Bigger tail surface with gentle throws, and move the CG forward :) Can't wait to see your next attempt! There's no shame in test-gliding a few hand launches into some tall grass or pillows.
Reduce weight absolutely. Run cad Sims of airflow and optimize wing weight and shape with drone. Use PLA aero or PLA light. It leads to yes some less durable parts but reduces weight SIGNIFCANTLY which is a huge win.. Then use CF nylon for those constant tension parts or payload. Also just make those control surfaces big man. They just will be a disposable part, you need to temper your expectations with 3d printing and take ADVANTAGE of the fact you can print a buttload of them. Design around your strengths, you are trying to make something that's more suitable for Sheetmetal than printing. That's my piece, SUPER COOL MAN KEEP IT UP.
doubt the thrust vectoring gimmick works here. thrust is simply too low for it to have any effect unlike in the aim9x which probably inspired this design. might even be negatively affecting the already limited thrust. may also want to consider using hot wire cut styrofoam for the body instead of 3d printed parts to massively save on weight
Cool project. I started modeling airplanes in the 60's. It's built way to heavy to fly as a hand launch machine given the thrust to weight ratio. The lower fins are a terrible idea for a reusable vehicle that belly lands. A takeoff and landing skid similar to model sailplanes would provide a place to mount a tow hook for rubber slingshot style launches. Another idea would be to bend up a wheeled dolly out of coat hangers that would cradle the airplane during rolling ground launches and fall away after take off. To get an idea what these cradles look like; look up control line speed racer videos. I think the speed of these things will amaze you.
I would definitely move the NACA inlet to the top for reasons you’ve already stated. There’s no reason to keep a failure point if it can be avoided. To address the wingtip camber; maybe make the wingtip spring loaded so that when it’s inside the fuselage profile it’s facing downwards (because of the upward NACA inlet) and when the wings pop out the springs force the rotation upwards so you get the same profile. (Think clothes hanger spring)
Probably nothing new to you but: Usually you would have the center off mass Infront of the wings, the wings produce lift the stabilisers produce downdraft to pitch up your nose. Modell size airplanes usually are a lot more easy to get airborne because of the highter thrust compared to commercial planes. Basically that means with enough thrust everything will fly.
You have a really high wing load, which puts your stall speed upwards of 40 mph, plus. I can see it’s slightly tail heavy and will make the controls sluggish once you get above stall speed. Thrust from ducted fans are slow in coming up to speed, but if you got this flying in it’s current state your are looking at minimums speeds of 80-120 mph. This would make an insane rocket boost glider using a G or an H in the booster stage and easily could handle rocket motor speeds of 200 mph+. For now, I would rebuild a prototype as a glider with a 5” pusher prop on a 2200Kv+ motor and no payload using the tube, current wings, and V tail control. Then you can work out the weight & balance and have controls that you can keep up with while figuring out how to fly it, and it will survive all ground hits as you figure it out. Once you have a light weight prototype like that is working and you piloting skills up to par, you can begin to add the more complex elements in. You could scale up in size and keep the wing load down and have slower flight speeds, otherwise it will be scary fast and you will need a very large area to test in.
Really cool idea. Can't wait for it to takeoff. For the fins you can also have the bottom two fins planar to the wing like with a F-22 or F-35 fighter jet. That should give you more control authority than two smaller fins 90 degrees from each other on the bottom
Ah yes, my favourite non-military engineer, building non-autonomous, IR guided, non-loitering munitions / non-cruise missile / non-air-intercept drone / non-autonomous recon platform.
Jesus at this point you are just building next gen autonomous drone.
Also i belive that you have exact ideas what can be put into that free space.
Then he will sell it to Ukraine and earn a ton of money
candy, right?
@@SpongeBob-xh8ir ukraine lol
@@DC_DC_DC_DC yep, kacap killer candies
@@SpongeBob-xh8ir Almost all of the equipment is given not sold, they have basically no money.
I just imagine some guy in the CIA building taking out a cigarette every time one of these videos is posted.
😂 indeeed
Russian or ukraine maybe
Learning is winning
cigarette
coffe
e're we go boi
WTF are you talking about? He is building stuff that is already in service with the US military, he is literally copying others ideas so poorly that he is failing hard when the info to do this is already out there.
9:51 "in terms of fan blades... we have no fan blades" 😭😭😭
you two collabing would go CRAZY
@BPSspace >>> Oh, are you familiar with rocketry?
😉 🤭
Do you happen to live in New Jersey?
you beat me to it
😂
no - otherwise it would fly.
@@haraldschurr1035really? He’s hand launching a rocket, what do you expect?
Lol
I’ve been designing and building competitive RC planes for a couple years in SAE aero and here is my brain dump:
1. Thrust needs to be increased, EDFs are not known for their static/low speed thrust, especially those small ones. Make sure you have an adequate thrust to weight ratio. Decreasing takeoff weight is crucial since your wing area is a design constraint. Increase powertrain battery voltage if you can, you’ll have to sacrifice capacity to save weight though.
2. Use an analysis tool like XFLR5 instead of ecalc, it uses actual airfoil data and VLM to solve for lift, drag, and moment along CG. See how much lift you’re making at takeoff speeds near stall angle. Check CG also, it might be unstable (especially on launch 3)
3. Increase aft control surface size, they look pretty small and won’t do much at low speeds. The EDF should help, but looking at the video it’s not enough. The planes longitudinal inertia seems really high especially with the heavy batteries up front and large fuselage.
4. I believe you are close to/a little unstable in yaw because you don’t recover very fast at 13:11. You have almost equal stabilizing and destabilizing side area on the fuselage and the control surfaces don’t seem to help with that since they’re moving to control pitch and roll. Increase your aft side area, this will help you recover from a large sideslip which seems to be the biggest issue on takeoff at lower speeds. At a 90 degree sideslip on the 3rd attempt the plane seemed like it had no intention of recovering from it. This could be done by adding fixed fins that are not your control surfaces. You will also dutch roll during these thrown takeoffs if you dont have yaw damping.
5. Add ailerons because you have little roll authority at lower speeds. Roll authority increases if your control surfaces are further outward- those in the back aren’t gonna do much if you have a large lateral inertia from the wings, but this all depends on how heavy the wings are. Your plane rolled a lot during these takeoffs and didn’t seem to want to recover. Dihedral won’t solve this problem. Include a flap too for higher lift during takeoff.
If you have any questions I’d be happy to answer in the reply comments or if you have a discord.
didnt know sae had a drone competition. I am the aero composite lead in my school's formula sae team. would have joined the drone one if my school had it
Imo I would agree with kyle points but I would give a try using some kind of launcher which would give much more speed at takeoff as first step just to make it launchable.
Oh good! I was worried we would never get to loitering munitions but here we are
WTF are you talking about? He is building stuff that is already in service with the US military, he is literally copying others ideas so poorly that he is failing hard when the info to do this is already out there.
@@thomgizziz you are so nice and kind😊😊
@@thomgizziz "the info is already out there" put up or shut up, ill see you in the warthunder forums
munition? this is an... rc plane made for... filming
@@thomgizziz Jesus Christ my man.
Correct me if I'm wrong, but Hatchet is meant to be initially launched via rocket with the EDF just keeping it in the air. As such, redesigning it to be hand-launched seems like a step in the wrong direction. I think a catapult is a better idea, as it can provide the higher launch speeds that are needed without having to deal with the complexities of rocket launches.
Or a magnetic linear rail launch system like Tom Stanton and others have built before. Smooth, consistent acceleration. Though that doesn't help the whole cruise missile vibe!
Given that he has never flown a radio control plane before this would be a step in the right direction. Slower flying means more forgiving and easier to launch/test. Once he can make the hand launch version work, then he can work on increasing the wing loading and going faster/autonomous
As someone who builds a lot of RC planes, I’d recommend adding ailerons, and possibly flaps, to improve lift and control at lower speeds during takeoffs and landings. As you mentioned, the plane seems too heavy relative to the available thrust-using lightweight filaments would help a lot. Also, it’s unlikely you’ll be able to manually stabilize the plane quickly enough during takeoffs and landings, so I highly recommend adding a flight controller for automatic stabilization. Finally, it looks like the elevator authority might not be sufficient with just the vectored thrust setup.
All that said, this plane looks absolutely stunning, and I can’t wait to see what you do with v2!
I don't know too much about this field but would it not be extremely hard to add control surfaces as well as the servos to control them when the end goal is for them to fold?
@@smellyboars4865 flaps would be a pain (and probably needed it if the wings are just bigger) but ailerons could added without too much extra complication... especially considering how complicated everything else on this is
Yes, it definitely needs ailerons, it has negative stability in the roll plane. A single micro servo would do that quite easily and cheaply. A rail/catapult launcher would certainly make getting it airborne a lot more consistent, and could be adjusted to give more/less speed on launch.
I disagree on the additional control surfaces, at least initially. Adding lightness is priority number 1, and ailerons aren’t really necessary when roll control can be carried out through X-.taik mixing. I’d instead move the wing up.
@@howlingwolven The X tail doesn't have enough of a control moment (force x distance) to be effective at low speed, maybe at Mach 1, but not at launch speeds. A micro servo is only about 2 grams in weight. Moving the wings up would certainly help.
Definitely reduce takeoff weight at least for early test flights. A rail launcher would be a game changer for getting you off the ground consistently with enough velocity to get enough lift out of the small wings. In addition, a rail launch would let you spin up your edf right before you launch. That way you are taking full advantage of your vectored thrust right as you leave the rail, when your control surfaces are going to really struggle giving you enough control authority.
Giant water balloon slingshot and pvc or wood rails
Thinking vertical launch with a potato cannon style launcher
Rail launcher, and put a large net downrange to catch those early failures. Later you can use the net for soft landings.
ERAU Grad, changing the air frame before getting it airborne is going to kill his understanding of how it flies in its ideal flight configuration. He should be focused on getting it airborne first then worry about changing it IMO.
Slingshot launch could help him dial in his v speeds without needing to redesign his aircraft.
1. Take off weight is too large, well, at least for the wing area you have chosen which is pretty much fixed if they are going to fold out of the fuselage eventually.
2. CG and wing placement seem to be mismatched, dangle it on a string from the mean chord, quarter chord point as a sanity check.
3. Control surfaces are too small for realistically any control during takeoff, and the fact you do not have ailerons would mean that they would need increasing in size compared to a normal set. For roll control matching ref area isn't sufficient as the moments are what counts, that close to the fuselage the moment will be tiny.
4. I'm unsure about the thrust vectoring, there is so much vorticity coming from that ducted fan that redirecting that flow is probably doing nothing apart from obstructing it, which leads me to the final point..
5. I don't think there is any thrust being made tbh. Compare just holding the plane at full throttle to what the fan is expected to produce.
Really cool project, I hope you can make it fly!
Pretty good points, I was also going to point out the thrust vectoring and thrust issues, I feel that the thrust vectoring needs to be eliminated, and the inlet needs a big redesign to let a lot more are in and directing it accordingly, I would provably go with an all around inlet or 4 inlets similar to that of a cruise missile, but nonetheless it needs a lot of air going in just because its fan propulsion, there is no pressure differential created by combustion and the air needs to enter as easily as it can, that design could hinder the air flow.
My thoughts exactly aswell, i'd argue that he could make it a biplan to double the wing area but even that may not be enough, and comes with additional drawbacks.
Yes point 5 seemed almost obvious, but I could be mistaken. With enough trust I would expect it to at least fly a few meters even with all the other points being an issue as well. I would've expected a thrust test inside. :)
RAIL LAUNCH SYSTEM 100%. take human error out, add much needed speed!!! make it repeatable.
Thrust vectoring is done with EDFs, stop it with the nonsense.
13:15 the way your friend is throwing it here is forcing the plane to pitch up. If he can hold it at COM and guide it into the air under the planes own power, you’ll be able to keep control. Alternatively maybe a rail like the V1 can help you eliminate variables here. Looking forward to seeing more!
It seems like the drone is also way underpowered, as by the 2nd launch he didn't pitch it up much but the plane just fell like a rock
Rail indeed, but that needs thrust, even with too much weight it should have enough thrust to at least fly a meter or two.
RAIL LAUNCH SYSTEM 100%. take human error out, add much needed speed!!! make it repeatable.
@@eriknulty6392 Or even just a bungee/hi-start system like a lot of the EDF guys use.
No, no he can't. There isn't enough power and way too much weight. There is more than enough info out there that this dude should have figured this out before he failed like this.
Welcome back switchblade 300
Put it on a vertical test stand and measure thrust. I don't think you have NEARLY enough. It should be able to take off from your unlucky friend's hand.
Related, maybe move to a 4" diameter? Bigger fan and fatter wings being the primary benefits.
Glad it's not just me, that looked underpowered before he even fired it up. Love the design, but it seems a little ambitious for that tiny ducted fan.
You should try a bungee launch. It is much faster and more predictable than a hand launch, especially with a new plane. Also before you risk your complex delicate powered drone, I suggest you create a simple unpowered model from a cardboard tube that is appropriately weighted and winged to perform the same as the real thing and try launching that as a glider. If it wont glide, at least a little then adjust things until it does.
this for sure. most of these lower thrust drones unfortunately jus cant take off without that inital push
A couple thoughts I had (although I don't do a lot of hobby drone stuff, I do work in aerospace)
1. 3d printed parts are probably not great for takeoff weight. It makes sense to use them for the aero surfaces where you need complex shapes, but you could probably cut down on their use in other places. The ball turret in particular strikes me as something that adds a lot of weight for something that still can't get a stable launch. Until you can get the prototype to reliably launch, maybe replace that and use a mass simulator to figure out what your mass budget for that payload is.
2. The inlet for the ducted fan looks like it's going to induce a pitch up moment that will vary with thrust, if possible, try replacing that with symmetric inlets so that you have more balanced aero forces. Also, having the inlet along the body like that makes me worry about losing thrust in high AoA situations, but at low speed, that's probably not as much of an issue.
3. I like the design of the control surfaces connected to thrust vector control vanes, but I worry about your proposed Y-tail idea. Non-symmetrical external control surfaces coupled to symmetrical internal control surfaces are going to require some complex control laws.
Some thoughts: 1. Are Center of lift/Center of gravity at the right spot? 2. Is the air inlet sufficient enough to generate enough thrust? Look at pictures of older Tomahawk cruise missiles. They had some kind of duct sticking out below for good air intake. 3. Is the thrust even enough for the over all weight? From the video it seems quite a lot of weight in the front. 4. The steering rudders might be a bit small to give enough directional authority?
This guy almost certainly did this already before flying, that’s like RC planes 101. It’s just an inherently unstable design.
I feel like with a set of canards (moveable or not) and a better inlet (or any way to produce more thrust), most of the issues could be fixed but that's just my guess, I'm no expert after all
you summed up all my thoughts perfectly, especially the on with the air intake. Good Job man haha
@@olekXDDDD Thanks ;-)
Add short canards at the front and back to help stabilize lift maybe? And recheck cg for main wing?
In thrust we trust bruh.
I think those TVC vanes are trashing your thrust.
Obviously weight reduction is great but stick a flow meter behind the thing and see what’s up before you go tearing it apart.
Regarding your thoughts:
1. Yeah, your wing loading seems too high, especially considering you don't have highly cambered wings or flaps. You don't share numbers but for reference, a wing loading of 3.5 kg/m^3 will give a flight speed of 20mph at a coefficient of lift of 0.7. Printing your wings out of foaming filament can reduce their weight by like 40%, though you'd also want to incorporate a carbon spar.
2. Larger tail is necessary, but remember it doesn't all have to be all-moving control surfaces. If you want to experiment with stability margin, you could add a passive tail and reduce its size with progressive testing.
3. I agree rail launch with bungee is the safest way to get this thing up.
I am by no means an aerospace engineer, just a hobbyist drone/rc plane pilot. Here are my 2 cents: these first launch attempts look very similar to that I've experienced with my first rc plane (zohd nano talon). The problem with such planes is that they have a relatively high wing loading and are pretty hard to hand launch. I crashed my plane around 20 times before I figured out that you need to give it *much* more kick on the launch. Because of that I decided to bungee launch it. With bungee launcher it took off easily on the first try. My bungee setup consisted of 10 feet of rope attached to 10 feet of elastic band, the part with elastic band is attached to the hook on the ground. The other side with the rope has a loop which is attached to a hook mounted to the airplane. The hook should be mounted on the bottom of fuselage a bit forward of aircraft CG. Thanks for the great video. Best wishes from Ukraine.
Slava Ukraini - Героям слава!
I think it needs to pass a glide test before you try powered flight. Make sure you've got the CG far enough forward to be stable and that the tail has enough downward pitch authority to keep the nose up.
I might consider a weighted test article to hash out launch and glide ratio. Same weight layout and construction just without all the electronics. Inherently unstable works for fighter jets but your drone should be able to track mostly straight and glide even a little bit without input. This will also allow you to adjust CG location to determine balanced flight profile.
So for your first ever RC plane you naturally designed a DIY cruise missile. 😂 This is fully insane and I'm 100% here for it. Nice work.
I wonder, why a swept back wing design? Swept back wings are worse than straight wings as low speed lift goes, also they have less than ideal stall characteristics
Also those control surfaces might be still a bit too small but im not sure
Another thing, which airfoil are you using?
I'd suggest to calculate a rough Reynolds number you'll be operating at and use an airfoil with a lower efficiency but better stall characteristics at first, then maybe move to a more efficient airfoil
yeah, swept back wings should just be better at high speed in terms of drag
Здравствуйте коллега -)
The swept angle isn’t that bad, imo it’s a tapered wing. I agree the surfaces are too small
@@wire3989 i think a straight wing could still give some benefits to the build, or maybe I'm just a straight wing lover😅
12:30 Looks possibly tails heavy but for sure the thrust isn't enough for hand launch. Ideally you'd want the EDF to almost support the "plane"'s weight. Not sure how much roll control you have, you may want more dihedral especially for Mk. I.
This is amazing dude. You casually made a Shahed-101. Looks like you learned why they use rocket assist take off. You also need a propeller about 3 times this size.
I was thinking rail launcher when your buddy was chucking it. I really think you need tail wings. Those 4 X-patten, or even 2 larger Y-pattern stabilizers, are not enough. I think you need the 2 larger Y-pattern rudders and 2 normal rear wings, then you'll home free. Stall and launch speeds will be much better. Some kind of carbon landing sliders might also be good. At least it when you are finally landing it, it will not risk tearing up the bottom. That's my 2 cents.
i am certain this man builds a missile and then sits and thinks for like 30 minutes about how to make it seem like its for amateur rocketry(i would do the same)
also: i would make it a stealthier cross section and put the inlet on the top.....ermmm i mean make it a lifting body and put the inlet on top to avoid FOD
Honestly, with that endoframe- skip the intake duct and let the edf breathe, just open frame it without the intake. While the intake might be fine at speed, all of the airflow at takeoff is coming from the fan/ vacuum cleaner lol.
great point
Maybe try attaching it to an existing flight worthy model and deploy once its at altitude, kinda like the space shuttle
Ooh I like this idea. In air deployment sounds cool. Although, given the use case which he outlined, it should still have the ability to hover at a constant altitude to track the rocket launch, so achieving stability at low speed is of paramount importance. But wait, how does he plan to hover again with TVC EDF firing at the rear and fixed wing?
i'll add some of my rc plane design experience here since i am also in the middle of designing a 3d printed edf plane.
i ran into some very similar problems with my first designs.
now i can't tell you specifically why it doesn't work because that can be a number of things. but overall to me it seems like this may be worth thinking about:
- weight. like you already said you should probably reduce the takeoff weight. i agree. i learned quickly that building light first and not second is a big factor in what works and what doesn't. you have quite a lot of equipment on board. and you also chose some rather dense filament. from what i've seen you want to have about at least 70-80% as much thrust as weight. at least at this scale. more is always better. i had some prototypes closer to 50%. those flew. but only in ground effect. and going into a turn would always lead to a crash. getting a more powerful EDF and or a higher voltage battery could help here but this usualyl also increases the weight.
- EDF aerodynamics. thrust verctoring is a cool idea. but here it may work against you. the TVC setup causes a rather significant disturbance in the airflow behind the EDF and probably creates a lot of drag and turbulence. which isn't ideal for thrust. in my models i learned that you get the highest thrust by having a very smooth EDF exhaust tube with geometry that starts with the diameter of the EDF and then becomes slightly thinner towards the end. something around 20% lower diameter. i also saw some very strong control effects from control surfaces like you have used at low speeds so the TVC may also just not be needed here. if the entire fin moves that has a larger effect than one might think. i was surprised by my own models.
- filament slection. you mentioned you used PET-G. for rc planes this is not ideal if you want to build light. me and a lot of others use a filament type known as LW-PLA. i get mine from colorfabb. this filament can be printed with an extrusion multiplier of around 50% so it's about half air by volume. this makes it more like foam and less like plastic but the weight savings are amazing. it is noticeably weaker than other filaments of course so you may have to use some carbon rods for reinforcement. i have a video about how i personally print LW-PLA on my channel (shameless plug).
- center of gravity. this is just from how hatchet was behaving when thrown. can be caused by a whole lot of other things but it looks like the CG might just be a little bit too far aft. i usually go with having it near the forward 1/3 of the wing measured at the root. i also sometimes make a glider model to verify the CG. where the model is entirely made out of LW pla and has no electronics installed so it's as light as possible. i then tape some small weight to the front or aft until it glides straight and then measure the CG.
i hope some of this can help. i'm excited to see it fly one day.
Please recalibrate the CG and CLs.
I would say the bottom fins (external) aren’t super necessary. It’d also reduce the number of prints needed. Great work 16:20
First! Love your videos, extremely underrated channel
I've been flying model airplanes for 23 years, but I've NEVER had such pain when looking at an "aircraft". 😅🎉
I love this idea, but there are some improvements I would consider. Firstly, I would use a launch rail because any fluctuation in launch direction is going to make it tumble, along with the high takeoff speed, it seems like the launch rail would help a lot. Secondly, I don't think the 4 fins on the back are a great choice for a horizontally moving aircraft, I would use 3 fins in the back (2 elevons and 1 rudder) and move the ailerons to the wings. Thirdly, I would find another way to mount the edf because it looks like it is barley getting any airflow with the side port. Fourthly, I would get rid of the thrust veins because it just looks like it is limiting thrust even more, and the added control isn't really needed because its not going as fast as a rocket. Fifthly, the round airframe is increasing the required takeoff speed even more, I would make the bottom side a little more flatter. I also want to clarify that I am not an expert and some of the suggestions I made may be incorrect. Also, I want to say that I love your videos and I am very exited to see this project will get completed! ❤
Seconding the need for a launch rail, the hand launches start the drone in a highly unstable condition and it doesn't have the control, speed, or altitude to recover from it.
the tube with winglet design really only works when launched from an airborne platform as its already moving fast enough to generate lift. the motor only has to sustain its speed
I would recommend building a model as similar as possible out of dollar tree foamboard. It is important that you get the CG right, normally about 1/4 chord or slightly forward works great. Testing a foamboard model would allow you to have the lightweight model you need for takeoff and hand launching while also allowing you to gain an understanding where you are lacking in stability. It may not hurt to try and throw your model in XFLR5 without the fuselage and run a stability analysis with your current cg location and such to ensure your model is statically and dynamaically stable. This will also allow you to quickly change your model in software and give you a good place to start with real world testing. I do not recomend sweep for a model like this because it is not going fast enough for it to consider compressible factors. The things I recomended should give you a good starting point and understanding, giving you more time to come up with possibly more thrust for hand launching or bunge launching methods.
The second I saw the first launch attempt, I thought in order: "too heavy" and "hmm maybe a bungee launcher would work. Seems you're on top of things and don't need my input. I'm excited to see what you come up with. My credentials are that I once duct taped a rock to a plane to balance the cg, and it flew great.
I love it! Did you ever find the camera housing for the last rocket?
No :( it’s still Missing In Action
@@LafayetteSystems
RAIL LAUNCH SYSTEM 100%. take human error out, add much needed speed!!! make it repeatable.
I don't know where my reply are going
@ if you’re speaking about my comment, I think I had an unstable internet connection and so it posted my comment twice. I’ll delete one to eliminate the confusion.
@@jordandegraaff
Hello
Use a catapult launcher, and check your CG.🤔 It appears to be tail heavy. Lastly, your main wings may be too large. The wing drag could be overwhelming the edf. Either make the edf more powerful or reduce the main wings. My 2.5 cents 🫡
10:25 Would adding a tight mesh cover over the inlet not be a good idea to prevent that?
The proportions of this are scale-like, but really bad for RC.
If i were you, I'd probably 1)increase the length and wingspan by at least 50% while keeping the dimensions of the fuselage. 2) rail or bungee launch for sure. This thing is HEAVY for its size, you're going to need so much speed 3) move the intake to the top, going to help with FOD Ingestion and a little with lift/pitch stability under thrust at low speeds, especially considering 4) tail feathers. These definitely need to be bigger. Like 3x probably. Without ailerons and no dihedral, your role control is going to be trash. The smallests gusts of wind will have this thing flipping over. The
Why do you use lidar for altitude keeping rather than GPS or barometric pressure?
Future TERCOM module?
Make the entire rear fin section magnetically detachable and use pogo pins to provide it power back there. Buy a compound bow and use that to get it up to launch speed; could probably make a stand utilize a garage door sensor to activate the full throttle condition to prevent any false launch events. I would also magnetically attach the wings as well if it remains fixed winged. Probably could add a simple parachute for free fall conditions as well.
Swept wings are gonna kill your lift at low speeds, no reason to sweep wings unless you are pushing mach
I have zero practical experience unfortunately due to lack of time and money but I did do a concept design for my Master's thesis and have some aerospace knowledge so some feedback from me: (Also I don't have much time so pardon me if I talk about something you already mentioned in video)
1. Try building the launch rail or do some figuring out how to hand launch properly. Launch 1 (I think, can't see much) and 2 you basically had a stall angle the moment it left Your friend's hand. I would avoid using the method in Launch 3 (pushing) as it basically asks for inducing a spin.
2. Looks tail heavy. Try moving CG forward or wings back. Now this is model aircraft world but in real world CG is placed in front of centre of lift. The main wing always creates a pitch down torque while the job of rear stabilizer is to create a pitch up torque. Since this is a model aircraft You could just aim to place CG perfectly at centre of lift.
3. Make sure that EDF of Yours is not limited by Your inlet. Hard to tell but looks a too small. EDFs are not compressors, they will struggle if inlet is too small. Ideally, area of cross section of Your inlet (at its smallest point) should be equal to the area the fan blades take. Additionally remember that walls of Your inlet will induce drag on the air coming in further limiting it (to consider when adding different twists and shapes in the inlet)
4. Looks very heavy and these wings look small. You want to minimize the weight as much as possible or increase the size of the wings., or both. Consider using a material like LW-PLA (Light Weight PLA) when 3D printing. It works by foaming when printing and at some cost of structural strength I've seen it able to reduce weight by up to 50% when setup properly.
5. Not sure if You did it but since You are 3D printing the wings You might as well optimize the wing by choosing a right airfoil. Go to airfoiltools.com , use a Raynolds Number Calculator and then use that number in their search options to find the right airfoil maximizing the lift or Cl/Cd while being structurally viable.
6. If You are using these fins alone and no ailerons on the wings then at slow speeds (when launching for example), especially considering the weight of this thing and the inertia in roll axis the wings give it, I would imagine You have zero roll control. Basically only thing giving You roll control at that point are the tiny fins behind the EDF. At slow speeds Your exterior fins do nothing and thrust vectoring does not impact roll axis.
7. And keep in mind the torque that EDF is introducing on Your roll axis, especially when launching at full power. These things can pack a punch.
8. To help with roll stability problem I would try introducing some dihedral to the wings.
These are the points that came into my mind seeing the design and launches. I love Your channel and Your projects! And I fully expect to see this full idea (totally not cruise missile) flying! Even if it takes few simpler iterations first! Keep up the good work!
This looks very interesting! What CAD Software did you use for it?
I use Fusion for my projects
@@LafayetteSystems Thanks!
I agree with the bungie launch /rail idea. You have to have sufficient air flow to activate that Bernoulli's type stuff, Haha!
The device never gets close to positively breaching stall speed. You already know this. I'm just thinking out loud here!
I enjoyed your vid.
I'm here for the first time.
AMAZING & fun journey young man!
I see two big problems. The thrust from your impeller is too low. Not only because it is a fairly inexpensive impeller but also because electrical impellers build up little static pressure in the impeller and the diameter behind the impeller is smaller than the impeller itself. I also think your center of gravity is too far back. For further experiments I would get away from the the thrustvector, use a better impeller and first build a traditional aircrafttail with larger control surfaces, in order to have a better chance of being able to handle any strange flight characteristics better.
Of course, a lighter aircraft always helps and could be successful when paird with a stronger impeller. If you want to achieve a good result, please only trust well-known manufacturers when it comes to thrust Statements.
Hope that helps.😊
You think his center of gravity is too far back when it was nose diving into the ground... really? You think you are helping? Your nonsense about "impellers" is even worse.
ERAU Grad here... I wouldn't change your aircraft, I would change your launch mechanism. You're going to have negative transfer of learning (about how your system handles) by changing the aircraft. You need more air speed to get enough lift for that thing... Maybe consider a slingshot launcher on rails?
Part of me also doesn't think that edf can propel that aircraft to give it the maneuverability you're looking for, but since I don't know those specs, that's a blind guess.
Some of my thoughts for moving forward with Hatchet.
1. Reduce weight - among your good ideas where to reduce, maybe try to lower your number of 3d prints, or optimize their weight with design or other filaments like foamy LW PLA.
2. Rail launching - great idea for repeatability and accuracy of launching, also you can test lot of variables like optimal angle, speed etc before going for vertical launching with booster
3. Change the intake to the upside - you will have much less trouble with testing and landing. With fixed wing version it is very fast change, with folding wings it can force the orientation change on the wingtips (basically turning the wingbox upsidedown)
4. Ailerons for the fixed wing version - i think you have small control authority with control surfaces on the body for small speeds. Maybe it is not a bad idea to introduce ailerons on the fixed wing. It should give a lot of lever for roll stabilization. You can decide to not use them during flight to learn more about your fins/tvc control system. You can also move them closer and closer to the body with each Hatchet refinement, until you ditch them alltogether with introduction of folding wings. This should be easy to implement with the creation of lighter/simplier wingbox you are thinking.
I wish you luck, this is great channel and you have briliant concepts of thinking.
Mark
I don't think the drone has the thrust necessary for its weight, but I also believe that instead of throwing it like a paper plane you should accompany it by jogging a bit before letting it go with a smoother transition.
She hasn't got enough thrust cap'n, that EDF jus' canne do et!
Catapult launch systems (giant rubber band) are normal for these types of high wing loading designs with ducted fans. The available trust is generally subpar until you have some speed behind it to feed the fan. This also provides enough air over the wings to provide lift.
Your stabilization also appears lacking in authority which is not allowing it to track straight, which in turn is upending whatever lift is available.
If you wanna keep throwing it perhaps you could use an atlatl (spear thrower)
RAIL LAUNCH SYSTEM 100%. take human error out, add much needed speed!!! make it repeatable.
@@eriknulty6392 No, if the system is so screwed that you can't hand launch it then he probably isn't going to be able to hand fly it either. And spamming the same comment over and over again doesn't make it a better idea.
@@thomgizziz thats where you are wrong, that heavy bird with tiny control surfaces will fly great (AT HIGH SPEEDS). but going 4 mph you may as well just throw a brick. I do know a thing or 3 about building and flying scale planes, been doing it for 25+ years. but at that curb weight it wont fly until MIN. 20mph and thats probably even still pushing stall speed. she is a 50+ bird.
I have some experience in hand launching RC planes. When I just started the biggest mistake I made (and I can see you make it as well) was to through the plane upwards. This makes the plane immediately stall. Even though it is counter intuitive you should through the plane slightly downwards (to a imaginary point about 10 meters or 30 feet in front of you) this way the plane will have enough speed to fly or it will just land without (or the least amount of) damage.
I love your use of common techniques like 3D printing and common motors to build things like this, its really unique and most things like this are behind military walls
Ottimo lavoro complimenti 👍👍👍👍😉😉
Secondo il mio parere da aeromodellista, la ventola ha poca trazione.
Il convogliatore dell' aria messo sotto , favorisce una cabrata verso l' alto del drone , e quindi lo porta in stallo subito.
La velocità di lancio è troppo bassa per creare portanza e per dare autorità alle parti mobili in fase di lancio.
La miscelazione delle parti mobili, in questa configurazione andrebbe bene se si usa il drone come razzo, ma non come aereo.
Queste sono mie opinioni, naturalmente non voglio insegnarti nulla, ma hai fatto un gran lavoro che mi ha interessato molto.
Mi sono iscritto al tuo canale , mi interessa molto lo sviluppo del tuo drone, continua cosi. like..👍👍👍👍✌✌
instead of a turbine fan, i recommend using a centrifugal fan and having a hollow in the base which stores the fan folded up, then a small linear converter pushes the propeller out and when it starts spinning, it unfold and propels the aircraft with more power, and you wont have to implement active vectoring which increases throttle drag by alot
Thrust too low, too heavy, not enough tail stabilizer authority (too small). I think you are focusing too much on making it look cool as opposed to flying well. For example why ducted fan? Why thrust vectoring? Why 3D printing instead of other construction methods which are stronger and lighter? That stuff is heavy and obviously not helping it fly better. A better way to do this would be to start with a commercial RC airplane that flies well, then modify it to add your payload to it. It flies well and the payload functions? Great, now you can make modifications to the airframe to see if it improves performance. The key is to make small changes and test the result of that. While testing airframe stuff you can have a dummy weight instead of the actual payload because as you're finding out, there will be crashes. Quick and dirty is the name of the game for prototypes. If it looks good you're wasting time and therefore iterating slower than you could be. It's tempting to have an idea in our head of what the final product will look like and just go right to that. It's much better to be constantly thinking of the objective and be open to anything and everything that gets you closer to that, regardless if it matches what you initially thought. Ugly stuff that works is better than looks cool but doesn't work. The UA-cam channel rctestflight is a superb example of this type of engineering. I worked as an R&D engineer, now retired and have designed and flown a few RC aircraft. This is my first time seeing your channel and I don't know your background so please don't take offense. Good luck!
I need this for searching for lost cattle on my farm. amazing design
Maybe print a Titan Falcon and get a FPV headset cheap plus IR video? No need to innovate when the solution is ready to print 😊 See YT videos, some militaries print them themselves to get cheap surveillance drones
@ but I want one that looks like a loitering munition for cool factor lol
@@TackshooterOG well, the Falcon gives you 300km range. But if you want cooler, how about the VTOL Titan Cobra? I actually just ordered parts for China for that one with FPV googles. Got them real cheap, like 60% off AliExpress since I lived in China and can buy it directly there. Still even with AliExpress parts, it's a damn cool morphing VTOL to Airplane
A proper check for COG/COL seems to be in order as well as calculating the stall speed.
The way it "glided" (or how it didn't glide) when thrown seemed to indicate something is seriously off with these factors.
Might you do test flights in NJ? At night?
Fully ceramic bearings should pull a bit more weight out.
As a college student studying aerospace engineering and apart of a college aircraft design / evaluation team here are some considerations possibly not mentioned.
Material choice: because the cardboard tube offers a high level of rigidity don't worry about the internal parts being super strong, 3d printed parts can be small with ribs, if a part is to have a large cavity use low infill or even lightweight "foaming" filament. This will reduce the launch mass without suffering huge losses to internal structures.
EDF Inlet: currently as the aircraft is flying the edf is trying to pull air out of the stream of air going around the plane. This is not only inefficient but could also be causing losses of with the tail section. As it currently stands a small bit of air is being pulled in by adhesion to the inlet and negative pressure caused by the fan. A proper inlet for the edf would go a long way especially once at cruising speed. This does not have to be much more than a little scoop that hinges down with the pivot point near where the current inlet stops. Additionally a thin grate could be added to help reduce injested objects and prevent the edf from exploding. The grate does not have to be super large or thick as where it is likely to pick stuff up (the ground) it should not be travelling super fast.
How heavy is that thing? It looks like it weighs about 2x too much to hand launch. EDFs have basically no static thrust so the rail launch idea is definitely a good one but its a lot of time and effort when you need to focus on getting the characteristics of the airframe down first.
I'd build a super light one just to test the advanced control system you are using. Maybe a foam board tube with a light 3d printed nose cone combined with moving the wings backward so you can use your existing edf location and power unit. Im biased as foam board is my bread and butter go to material for model planes.
Also are you printing the plane out of any foaming light weight materials? I think they have just about everything in a LW version for RC planes nowadays.
If you need that payload weight to stay the same you can only take so much weight out of the structure while keeping it in that soze and form factor. If it were me, I would shoot for something about 30% to 50% larger while trying to keep the weight of the structure relatively the same. I would also do a pusher prop on a thrust vectoring base along with ailerons for controls. If you want to keep the wings light and simple canards can handle the roll and add a lot more pitch control.
Hope this helps! If you want to have a more in depth conversation let me know. I'll hop on the RC testflight discord.
Aero eng & rc enthusiast here. First of all, dope project. Second of all, I think your solution ideas will work. The issue you have is a result of your tail fins being too small; look into tail volume coefficients to size them. Also, I’m sure you already know this, but CG should be located right abt quarter chord on the main wing or more forward. Further forward it is, higher cruise speed will be. Finally, make sure your TWR is above ~0.5, higher the better. Good luck!
Great job! Your 3D printing skills are top-notch. My little bit of advice is you need about 3 times more thrust. With your current weight, it will be hard to achieve with this diameter housing. Your other option is to slash your weight. As fun and cool as 3D printing is, you may need to use more lightweight building techniques. Now all this advice relies on the fact that you are going to hand throw this aircraft With the rocket assist take off the unit may fly but will have an extremely high stall speed. Personally , I think more power is your best bet. Good luck! 😊
Very cool and ambitious project! Completely new desings are expected to end up in aerodynamics hell so hang in there! You should consider collaboration with another youtuber like Think Flight on this. He has experience designing and building winged drones so he might have some valuable input! In the meantime here are some ideas:
1) Push the center of mass forward, probably a lot. The aerodynamic center doesn't have enough leverage to keep the thing prograde.
2) Add ailerons on the wings for roll: Control authority far from the center of mass is a big yes.
3) I like the bigger top fins idea but a more traditional design might be more in order here for better control separation and whatnot. Rotate the back 45 degrees, add one big rudder fin on top and a bigger set of horizontal fins or even wings that can take over roll as well if big enough (they can also be set upside down for negative lift if you end up pushing the center of mass way forward and it ends up front-heavy).
4) Push or rotate the wings up to get a dihedral effect. Right now is looks like you get the opposite effect which actually gives the drone the tendency to go upside down.
Good luck! Subscribing for this!
A few observations:
The swept crescent wing is always a bit of a tricky approach, I built a few high speed slope soarers with that planform a few decades ago and they were super sensitive to CG positioning.
Looking at your screen shot of the eCalc data, your 'Stabilizier Volume (Vbar)' is 0.16. From the eCalc page:
The Stabilizer Volume (Vbar) is a value for manoeuvrability. The lower the more agile the aircraft gets. Typical values are:
0.5...0.9 Trainer
0.3...0.6 Aerobatic
0.5...0.8 Glider
0.5...1.1 High-lift Jet
0.3...0.5 Combat Jet
0.0 for Delta & Flying Wing (due missing Stabilizer)
It is possible that your choice of wing aerofoil is creating a nose up pitching moment, and the tail is insufficiently sized to counteract it, quickly/instantly leading to a stall. Also remember that the V-tail will have less authority than a true horizontal stabiliser. So when entering the values for it into eCalc used the projected plan view for span.
Perhaps choose a reflexed aerofoil for the wing, it will have a much lower pitching moment, so you can get away with small tail surfaces.
Launch speed looks far too slow. As other have said, look at a rail launch, or even something as simple as a bungee/hi-start launch. A lot of scale EDF guys use these to get heavy underpowered jets into the sky safely. Owlplane has a download for a launcher if you're looking for inspiration. It generate 25kg/50+lb of pull.
owlplane.gumroad.com/l/tsqpe
Hmm, but he's not using a V-tail but a cruciform tail, i wonder if he just used V-tail data and divided it by 2 as he doubled it?
@@belliduradespicio8009 Very true. What I meant was that the 'V' of the tail surfaces would result in a much less efficient lift vector, due to being inclined at 45° to the direction it is needed. The resulting component is going to be much less than would be achieved with a proper horizontal stabiliser. A V-tail equipped aircraft often needs 10-15% more surface area than a conventional horizontal-stabiliser equipped aircraft would.
Here are some ideas.
1. As general rule of tumb, place CoM slightly ahead of lift center, it improves stability but decreases controllability. If you put CoM behind, the aircraft is unstable but highly manoeuvrable, which requires good autopilot and thrust.'
2. Rail guide for takeoff. Even a simple rail would make takeoffs easier, plus you could add catapult mechanism to it for increased chances of success"
3. Remove thrust vectoring, it quite often destabilises simpler guidance systems at low speeds.
*P.s. i have extremely low IRL experience, most of these thoughts come from the KSP experience and other UA-camrs of .
I want to help you build a scanner based camera for this project for ground mapping
Some suggestions for your design.
1. Find and use a lightweight filament for this print.
2. Find and use some flight stability software.
3. Refine the inlet for the duct engine. I would add three duct inlets. One on the top and two on the side.
4. Increase the size of the wings to help with lift.
5. Move the wings to the aircraft's top to help with stability.
6. Rework the electronics so the center of gravity is just under the wings.
7. Remove all unnecessary equipment and only put what is needed to fly the drone.
8. Increase the size of your control surfaces.
I hope these suggestions help.
To add to the sea of suggestions, you can lose a little bit of tail weight if you switch to two tail servos, with the two remaining surfaces slightly offset from each other longitudinally by a few millimetres; then your thrust vectoring vanes, supported by a carbon fiber tube running through their center, can pass by each other, forming a X-shape overlapping vanes. One (or both for maintaining control authority balance) would have V-notches in the middle (hence the need for the CF tube) to allow for whatever max deflection angle is desired without colliding with each other. By running them through to the opposite sides of the exhaust duct you also gain a greater supporting moment against dynamic pressure exerted on the fins, which could allow you to reduce the structure around the fin mounting points (as well as eliminating the mass of two servos and their wiring).
air intake must be on top not on buttom landing would suck debrie in
Couple thoughts based on the RC plane I made years ago now.
Most of all, Get Real Flight RC flight sim, with a controller.
This will allow you to build your exact aircraft with all the dimensions and similar if not exact parts. I did this so the model had all the same parts, and settings for your receiver and controller. So the servo mixing, throw angles and percents are all the same.
I’m willing to bet you’ll get the same exact outcome in the sim. The beauty with that is you can adjust your center of gravity or thrust with no effort. Try to fly again to see what helps. Same with thrust vectoring and control surface iterations.
Start with the exact model as built. The. Tweak it to make it flyable the way you want. Changes in CG, CT, thrust ramp speed, weight, all of it.
You can test in the sim throwing without thrust. You might find it doesn’t roll. If so, you have a torque issue and need to ramp throttle up and maybe mix with ailerons.
Once you have a flyable model, that handles how you like. that will guide you to designs changes you can make to get there.
If you enter in everything exact and it flys like crap in the sim. Be prepared to have the same issues IRL.
Mine was a push prop designed with a huge brushless motor and prop with heavy pitch. That thing basically nosed in if I just lit up the throttle. As the center of thrust was a good 4 inches above center of gravity. And center of mass really. But at a glide the handling was good. Well, once I figured it how to make it not so tail heavy.
My two suggestions for your aircraft would be to lock thrust vectoring for now. Treat it as a glider, as much as you can. So you can see how well it handles without thrust.
Then also get a gyro based stability controller. It’ll plug in between the receiver and servos. That can help compensate for some of the behavior like when you throttle up with too high thrust or torque. Or when you start getting into that stall zone.
Lowering the weight and raising airspeed as you said will really help. You can use a flight controller to get some artificial stabilization to help you out. Larger tail feathers will also really help you out.
I recommend not investing into Spektrum too much. Get an inexpensive Radiomaster radio and use ELRS. The receivers are much lighter, less expensive, and better range. They are also more compatible with flight controllers.
Same thing happend to me with the edf .Something sucked in and crushed it's blades. Good thing is KT boad protected me .If it didn't I lost my eye that day.Also I think hatchet need more thrust. That EDF isn't enough.
For test launches you can bungee launch or discus launch it if chucking doesn’t work. Saves you from building a launch rail right away. For a bungee launch, a slot in the bottom of the airframe engages a hook on the launch rope which is elastic. Stretch out and let go, and Hatchet will fly off.
For the discus method, ensure your wing spar is rigidly installed. Put a finger hook through the wing tip, hold Hatchet on the pads of your index and middle fingers, and spin it around like you’re throwing a discus. You can throw a lot harder that way.
I think the problem is the weight distribution in the body content and enough power for the engine, aerodynamic accuracy etc... but I like it. Don't forget the rear wings they are very small, they are suitable for rocket concepts and not the planes.😅
For hand launching try a wing tip launch. Hold it by the wing and spin and then release. Don't need as much strength that way. I am worried about the lack of control surfaces on the wings making it harder to control at low thrust. Another test is to empty out all the weight and see if you can get it to just glide.
I can't wait to see the changes you make to get Hatchet in the air.
Best of luck
At the flight attemps your friend seems to be trying to launch/throw the drone off its center of gravity which naturally puts its in an unstable state causing it to stall/drop. I'm no expert on RC planes but I've flown and thrown them enough to know how not to launch a RC Plane/Drone. Always try to throw them FROM their center of gravity or mass. at 13:15 your friend also seems to be thrusting it from the exhaust which gives it an unstable amount of force pushing the center of thrust way back and increasing the AoA of the wings in return causing a stall. Another thing that he seems to be throwing the drone in a curve which should not do; what he should do instead is thrust/throw the drone as straight forward as he can without altering the drones course/orientation. If I weren't able to explain things good enough; please pardon me for my English as it is not my native language :)
It might be a little heavy!!! But it looks awesome!
This is sick dude! Nice work
While the weight, wing area and low thrust don't help with the hand launches, some better technique might've made it fly at least for a moment. The most consistent way i found for hand launching is by grabbing the fuselage slightly (very) in front of the CG, running as fast as possible while maintaining somewhat constant angle of the plane, and then gently throwing it forward. The way this plane was launched (or rather, thrown) gave it so much angular momentum every time, it probably wouldn't recover even with infinite thrust.
Also, running with the plane in hand gives you some feedback on how the lift is, and if the plane is correctly pitched for launching. The runups were very short so there was no way to correct a wrong aoa.
Good luck with the next iteration, cant wait.
Missing fan blades? I'm guessing that's why most of the intakes are on top of jet drones. Keep up the great work.
I think your problem is most likely the tail size. Ultimately you need to counteract the pitching moment of the wing. Traditionally this is done with a tail an elevator. You could use your thrust vectoring to do the same although that will be much more challenging to get right. I’d start with a larger tail to get it flying. Then start shortening the surfaces as you learn to rely more on the thrust vectoring.
Great wildly ambitious project. 2question/suggestions:
1: What is the stall speed? - can your helper throw the vehicle (or anything) to that speed?
2: thrust? From the very limited view it looks like it is frankly insignificant relative to the mass of the vehicle. It is obviously unable to visually accelerate the vehicle in the first 1-2 seconds. Your idea of reducing total mass is good. But I’m thinking you need to maybe triple the thrust! Or how about rocket assistance for 5-10 seconds? Good luck
I am only 1min into it and am thinking, why not have the duct entrance on the top, the suction force should reduce the overall weight in the air?
Rocket rules still apply to planes: center of gravity vs center of pressure is incredibly important. That huge wing has moved your center of pressure WAY forward, and those itty-bitty fins just cannot compete with them at hand-launch speeds to provide any realistic stability. Rockets can keep CG comparatively aft, only slightly forward of the fins, but on airplanes the CG is often around 1/4 to 1/3rd from the leading edge of the wing, for almost exactly the same reasons.
Bigger tail surface with gentle throws, and move the CG forward :) Can't wait to see your next attempt! There's no shame in test-gliding a few hand launches into some tall grass or pillows.
Reduce weight absolutely. Run cad Sims of airflow and optimize wing weight and shape with drone. Use PLA aero or PLA light. It leads to yes some less durable parts but reduces weight SIGNIFCANTLY which is a huge win.. Then use CF nylon for those constant tension parts or payload. Also just make those control surfaces big man. They just will be a disposable part, you need to temper your expectations with 3d printing and take ADVANTAGE of the fact you can print a buttload of them. Design around your strengths, you are trying to make something that's more suitable for Sheetmetal than printing. That's my piece, SUPER COOL MAN KEEP IT UP.
Where is your cg?
What is the load of surface area? Cotrol surface seems too smal
doubt the thrust vectoring gimmick works here. thrust is simply too low for it to have any effect unlike in the aim9x which probably inspired this design. might even be negatively affecting the already limited thrust.
may also want to consider using hot wire cut styrofoam for the body instead of 3d printed parts to massively save on weight
Cool project. I started modeling airplanes in the 60's.
It's built way to heavy to fly as a hand launch machine given the thrust to weight ratio.
The lower fins are a terrible idea for a reusable vehicle that belly lands.
A takeoff and landing skid similar to model sailplanes would provide a place to mount a tow hook for rubber slingshot style launches.
Another idea would be to bend up a wheeled dolly out of coat hangers that would cradle the airplane during rolling ground launches and fall away after take off.
To get an idea what these cradles look like; look up control line speed racer videos.
I think the speed of these things will amaze you.
I would definitely move the NACA inlet to the top for reasons you’ve already stated. There’s no reason to keep a failure point if it can be avoided. To address the wingtip camber; maybe make the wingtip spring loaded so that when it’s inside the fuselage profile it’s facing downwards (because of the upward NACA inlet) and when the wings pop out the springs force the rotation upwards so you get the same profile. (Think clothes hanger spring)
Probably nothing new to you but:
Usually you would have the center off mass Infront of the wings, the wings produce lift the stabilisers produce downdraft to pitch up your nose.
Modell size airplanes usually are a lot more easy to get airborne because of the highter thrust compared to commercial planes. Basically that means with enough thrust everything will fly.
You have a really high wing load, which puts your stall speed upwards of 40 mph, plus. I can see it’s slightly tail heavy and will make the controls sluggish once you get above stall speed. Thrust from ducted fans are slow in coming up to speed, but if you got this flying in it’s current state your are looking at minimums speeds of 80-120 mph. This would make an insane rocket boost glider using a G or an H in the booster stage and easily could handle rocket motor speeds of 200 mph+. For now, I would rebuild a prototype as a glider with a 5” pusher prop on a 2200Kv+ motor and no payload using the tube, current wings, and V tail control. Then you can work out the weight & balance and have controls that you can keep up with while figuring out how to fly it, and it will survive all ground hits as you figure it out. Once you have a light weight prototype like that is working and you piloting skills up to par, you can begin to add the more complex elements in. You could scale up in size and keep the wing load down and have slower flight speeds, otherwise it will be scary fast and you will need a very large area to test in.
Really cool idea. Can't wait for it to takeoff. For the fins you can also have the bottom two fins planar to the wing like with a F-22 or F-35 fighter jet. That should give you more control authority than two smaller fins 90 degrees from each other on the bottom