One thing I noticed is that they say that they start the drop with full speed break to level out. I believe the virgin pod model does the same. ua-cam.com/video/HDET3VuT9jE/v-deo.htmlsi=aoHC2XAjqSeVzoZr&t=90
Food for thought:! The rotor wash from the quad is causing the initial instability since it is tailwind blowing against the control surfaces, causing it to use up altitude to get stable.
@@pinkpanther8427 From the drone, 2 thoughts. Guide rod angled away from the drone, or towing it like a glider and releasing. Both have their own challenges.
@@pinkpanther8427 Maybe two long rods to guide it and then keep the drone moving so their isn't a column of toward wash for the aircraft to be traveling through.
Making delta-wing-shaped holes in the ground is something I excel at, so here's some painfully-obtained suggestions. Highly-swept deltas have vanishingly small inertia in roll, but a load of inertia in pitch and yaw. Their tiny wingspan also provides negligible roll-damping. This is a bad dynamics situation, so if they start to tumble, it's often game-over = flat spin/frisbee. Using aileron won't help you recover; it only makes it worse. We lob little 'shuttles' piggy-back off of model rockets using a catapult: if the release isn't clean and the delta starts to corkscrew, she's a gonner. The vertical tail on your seriously-cool 3D printed glider is way too small for the large yaw inertia, but that's an easy fix. Bear in mind that at high angle of attack, the fuselage is blanking off a lot of the flow to the tail, so folk tend to go with twin-tails. The high-frequency roll oscillation is what highly-swept deltas do as they're stalling. I call it 'wibble'. The vortices coming off each wing are battling it out over the centre of the upper fuselage. If you don't get the nose down sharpish, then one vortex will eventually win, causing the delta to roll right over. I've written some notes on this stuff on our website: www.aspirespace.org.uk/downloads/Winged%20rockets%20and%20boost%20gliders.pdf
Is this why we don't really see delta wing aircraft used often, if at all? What you're describing exactly matches my experience with delta wing rc planes; supremely unstable, high speed required, be extremely cautious not to stall
Thanks William, don't know about 'expert', just been doing it a long time! The thing about Daniel's brilliant vids is that we get to see exactly what's happening from many camera angles, and even from the cockpit. Watching this video lit-up so many lightbulbs: "Hey, I've seen that glider behaviour before, but never that clearly." Daniel's footage of the glider dropping off the drone was a real eye-opener.
Hey! Aerospace engineer here. Absolutely love your iterative approach! Do not underestimate the difficulty of what you're trying to do. There's a reason why planes aren't dropped from the sky. Basically, any "properly" balanced plane will actually resist the motion to level out. As it falls vertically and you increase the angle of attack by trying to level out, the lift increases which creates a pitch-down moment about your center of mass. Trying to level out therefore requires you to pull on the stick quite hard. This is desired for a normal aircraft in longitudinal passive stability. As your cg is likely forward because of this desire for conventional stability, since you start at 0 airpseed, you have no lift and therefore you're more of a dart than a plane for most of the flight! That is your second problem: your 0 initial airspeed and low acceleration due to having no propellor to generate thrust. This makes your lift extremely low at the start and your control surfaces are very ineffective. Remember, lift scales with the square of airspeed. Hence you're stuck in an immediate stall and you get into a spiral motion or flatspin like you see in the video. That's also why the plane with the big bolt on the bottom from the intro did so well. You get much more immediate airspeed. Excessive wing loading is bad, but too low is also bad especially for an unpowered glider! You see that with the foamy, where at some point it's more like a falling kite than a plane. Finally, the propellor wash from the drone certainly doesn't help increase stability. You're likely dealing with all kinds of vortices, which is why you see an improvement when the rod is added. All in all not bad work at all! But you're definitely doing something that's not as straightforward as it looks!
The main reason I believe the shuttle designs don't work well is because the design of the space shuttle was made for hypersonic flight. Even while landing, the shuttle was moving very fast. Theres just not much lift in that design to get stable flight at low speeds. This is challenging stuff though. The one thing I might recommend trying is maybe a adjustable wing? So u could get more speed at a dive, and more lift while gliding... Kinda closer to an old fighter plane like the F-111 for example. Might be worth a shot!
Or try first with some traditional wing design modelling some known airplane and only try the delta wing stuff after succeeding with that. Longer steady glide path with less emphasis on the last second pull up.
The Space shuttle enters Earths atmosphere at over 17,000 mph and slows itself down through a series of flight movements to final approach at 215 mph by 3,280 to 2,800 feet above ground. Final nose flare before touch down and arrester chute deployment is at 179mph and final roll out to a stop.
My father worked on the NASA Space shuttle. He was a mechanical engineer. He worked on the vibrations in the rocket turbo pumps and the heat shielding. He worked all his life trying to make a circler wing aircraft. The advantage of them is the huge speed range they can fly at. The one big trouble is "dutch roll" you can see the same effect in early lifting bodies. That is why NASA had to add the small wings. My father sent letters back and forth to Alexander Lip push the famous German aerospace scientist. The father of the Delta wing on the F,102 and F-106 and all other deltas. A brilliant man
For anyone building flat foam wings.... Add another strip of foam on top of the leading edge that is 50% chord or a bit less. And round the leading edge. This creates a KF airfoil (KFm-2) and it will fly way better.
That landing at time 7:07 was excellent. Moving the CG back sure helped.👌🖖 Looks like the 3D printed plane needs a larger vertical fin, maybe even one under the tail to help tamp down the roll oscillations. You could even add a rudder with a gyro to help.
Dream Chaser's 2017 test flight used a three-point rig that released the vehicle while in stable forward flight. Your lifting-body planes spend half their decent just getting to stable flight, so a Dream Chaser styled release might benefit your tests.
Sometimes when confronted with destructive and yet iterative testing - it can help to have some "pre-iteration" done where you map out your experiment and have several test samples ready to go on test day.
One thing that would be super cool to do and very useful for a landing would be having a sensor measuring AoA. I know this because I've made the eletronics for it in the past but never managed to put it on something flying. Maybe my next plane will have it. With 3d printing capabilities, making a sensor like that would be very easy. Cheers for the great content mate!!
you start off with the drone making a lot of down wind from the prop wash so why not use some forward speed and release in the proper direction like into the wind toward the clear landing area of the field.
I've designed and built aircraft like this in the past and I found an interesting problem that you have to account for in the design you can't use a central rudder or vertical stabilizer you need to use tip rudders or tip stabilizers or that central stabilizer needs to be about seven times taller The problem is your crank arrow delta is shadowing your vertical stabilizer so you essentially have a Delta wing glider that has no vertical stabilizer at all until the teams forward fight speed the wing prevents the stabilizer from seeing air so the aircraft flies as if it has no stabilizer I build a 14 ft long version of this that was a rocket glider very similar wing design and had the same problem I would get into a flat spin and it simply would not recover because the Delta wing shadowed the stabilizer it wasn't until the aircraft inverted exposing the stabilizer to the air stream that it then straightened out and of course crashed :-) The solution is to put tip stabilizers in the design that protrude both up and down this way no matter what orientation the aircraft is in some of the vertical stabilizer surface area is exposed to the air stream at all times this is one of the reasons why the space shuttle has such a gigantic vertical stabilizer in order to get it out of the shadow of the cranked Delta
This might also explain your role oscillation in the later model as you pulled up you were basically erasing more and more of the vertical stabilizer as you slow down and shadowed it with the wing although I'm not sure of that as long as you have forward airspeed you should be okay your solution might be as simple as putting a small stabilizer on the bottom of the fuselage so that no matter which side ends up facing the airstream on release you have some vertical stabilizer exposed to the airstream
Agree, the shuttle uses a super tall vert fin to get enough clean air. I'd start there. I bet he could test it just by taking the existing design and scabbing a piece of foamboard on up there.
I wonder if some type of ground launch system wouldn't be better? Catapult or rocket motor? This way you are already in forward powered flight and then convert to gliding under full control?
No parabola for descent curve. A curved path of fastest descent under uniform gravity is known as the brachistochrone curve, which is a type of cycloid
They are controlling AOA, not position. There would need to be a controller to target position for this to be true, and it probably doesn't work because of aerodynamics
@@KnowledgePerformance7I don't really think, that it is AOA, i would say that it is pitch, but I also agree with your comment. For the optimal path it should be based of some position system. I think that having some sort of system, that would meassure all of the flight parameter (as he mentioned in the video) and then it would compute the things to do in order to stay on the optimal path would be best, but also more challenging.
I love this type of work you do. I am an Aerospace Engineer by training and by trade, ground induced lift has always been near and dear to my heart. The Space Shuttle is an unpowered glider which is the same class as a hang glide. You don't even need a pilot's license to fly it. The shuttle's flight guidance seems counterintuitive because it is driven by an energy management system not a flight program.
My first thought would be to increase the vertical stabilizer. I have designed quite a few model airplanes myself, but never for this part of the flight envelope - so I may be wrong. However, this was my first thought.
I wonder if the downdraft of the lifting drone is setting it up for failure giving it less altitude to work with. I like the idea of dropping from forward flight where it starts off in a stable mode out of the gate. Probably would make things more predictable and tunable.
Rotor wash for sure is the biggest issue, you should do a short mission that moves from point A to B (then releases the plane) and have the quad move back to A. Like 10m movement and have the plane drop at the end of that point, at least you would only have the instantaneous wash and not the built up loiter wash.
Ya, I'm in agreement. Something needs to be designed into the wing/lifting body to so that it naturally seeks stability. I don't know if there is enough "wing" here to do what you suggested, but I think that's the right idea.
Would it help to have the glider much further away from the drone before the drop. That might minimize the amount of turbulent roll it experiences from the quad copter?
This type of projects is really cool. I made an rc plane and wanted to add some sort of processor to it to do some playing around with it, what sort of flight controller would you recommend? I'm thinking more of something I can program directly instead of runnig things like betaflight
try adding features to improve the low speed stalling situation... like humps in the leading edge, which funnel more air across the surface. also, placing the antennas in front of the leading edge didn't do the airflow any good, since they cause irregular pressures
I would want a small sensor that could sense air and calculate ANGLE OF ATTACK or AOA. Modulating this to near 1.00 just prior to touchdown would yield the flight you desire. But it would need a computer to sense air, direction, altitude, etc. Then you could program it for the ideal flight.
I think the Lidar might be better for this specific kind of situation. I think the differences in pressure on the altitudes where you want it to adjust are just a little bit too small for it to be accurate every time. And sometimes you would get good performance because conditions are perfect enough. Lidar doesn’t worry about air pockets in it’s sensors though
try putting some winglets on. Also you might want to sharpen the forward strake leading edge and you need more or a flat top than a rounded one for lifting bodies to work best.
try putting the vertical stabilizer on the fin. not the center. the blunt nose prevents some of the air going to the vertical fin, rendering it useless. hence why nasa put theirs on the wingtip.
Use a longer tether to stay out of more prop wash and it will start flying sooner... that release cost too much altitude with the dirty air just below the drone. You can see it clearly everytime. Very cool.
So many spins! IMO, a larger vertical stab will help recovery from the spin more quickly. The space shuttle has a huge vert stab and rudder. Alternatively, adding winglets may accomplish the same faster recovery. Maybe try releasing while the drone is moving forward rather than in a hover. This may help reduce the initial affects from the downwash. Great videos!
I've loved watching you since you were a kid. You really maximize the possibilities of RC hobby grade equipment and open-source automation capabilities. A few small tweaks to your development goals and you could have a multi billion-dollar Defense/Defense Research company using your current skillset to shift the cost structure of short-range anti-drone air defense and front-line guided munitions. Not kidding.
Hi. Would drpping from a plane yield a better result? Seemed like downdraft from the quad was affecting it on release. Just wondering. I'm no engineer.
Maybe if it starts more horizontally it will fly better. Hook up the launch rail at something like a 30 deg. angle to the drone's level flight. Fix remote controlled clamp(s) on the rail that hold the glider in that position and release it from that angle.
I'm always late to the show. My only experience with gliders was a little circuit board I made for a friend who flew model gliders, it would beep a piezo if a servo movement drew the power rails below a preset limit, this way it would start making a noise before the batteries went flat.
You make enough new airplanes that it might be cool for you to make a wind tunnel to test them in and fine tune the controller. Might make for a nice build video and help get more successes out of these builds.
Hey Daniel I think your vertical stabilizer is in the wake of the delta wing during spinning and cant stabilize it. Try a downward facing one or winglets (up and down). That should help.
Hmm. Are home-made wind tunnel tests an achievable idea? Since a big issue here was repeatability, maybe there's something in between CAD and real life that could provide further data. It sounds hard to build a homemade wind tunnel that can do that, but Daniel and builders like him have shown that home engineers can do all kinds of tough projects.
As these are actively controlled putting the weight very nose heavy should be possible and still get it to 'fly'. That would then help it accelerate nose down more cleanly as you have put the drag and mass far enough apart... Of course if you or the code don't pull up at the right time it will turn into a lawn dart, or stall and then turn into lawn dart, as you will really need good airspeed to have enough control to lift the heavy nose...
Great video!. For some reason I started watching it after I first woke up and it turns out it was a really good way to get my brain ready to face the day. Maybe because of how you include all your experiments, not just the good ones? I'm going to try adding your videos to my morning routine and see if it helps. Thank you!
Many full size aircraft use barometric altimeters ABOVE a certain height. Radar altimeters at lower altitudes, as at a certain altitude, they lose effectiveness. Baro is not stable enough close to the ground. If you have the means, fly over a pond/body of water to a grass field, then over a road, measure the barometric pressures at various altitudes.
I would entertain using PETG in place of PLA for your gliders. It’s a little more elastic and ever so slightly more dense than PLA. There might not be a whole lot of differences but it’s worth a shot.
I wonder if you could make the nose of the plane from some inflatable material like one of these air mattress thingies you use in pools. This should soften nose impacts to a more survivable g loading without adding too much weight.
I have a shuttle design I want to build and launch as a rocket and then have it return to base by gliding using ardupilot. The thing is, it would be starting at high speed, reaching its peak altitude before switching to auto pilot. Level flight then circle the home gps until it lands.
Something to think about:! Full scale the release is done from a forward flying aircraft. The tailwind from the quadcopter is probably a cause of instability.
Hear me out: Downward facing catapult launcher on the drone to give the glider some initial airspeed. Maybe just something like a couple rubber bands to get it moving and give it a more consistent launch.
So, one thing to consider is that the oscillation may be a result of over speed and not over tuning. You very easily could be exceeding the max speed limit of the aircraft, causing it to become unstable.
I went through some of this waaaay back experimenting with Deltas and other flying wings. First, most of those models looked like they need much taller vertical stabs. At such low Reynolds numbers and short coupling, a small vertical doesn't have the authority to keep it pointed in the right direction with all of that wing wash spiraling up at the tail. The fact they never really achieved stability shows that. CG is also super sensitive at small scale like this, so there's a lot at play. I love your videos and you do awesome work so I commend the work involved to iron out the bugs!! 👏👍
Too small vertical stabilizer. Try to add some winglets or larger fin. Long nose generate center of aerodynamic buoyancy in front of COG. Delta and flying wing configuration shows yaw instability as aileron swing. You can test it with xflr5. Had similar problem with one of my projects.
9:31 'reverse' the orientation of the elevon servos, and move their mass INBOARD. IMPROVE the carry/release system. use multiple to single hanging point. hoist the model at/near its cg. 9:42 don't certain control components NEED to located at the cg/c-m.? d
the first lifting bodies you've made only get lift from the shockwave created when going supersonic... when it goes slower it is not a "true flight" but more of a controlled falling...
Have you watched when James may flew a model glider 21 miles autonomously. The glider was dropped from a helicopter but to protect it from the downdraft it was in a box about 50 feet below.
so instead of gluing it together, consider "pinning" it with carbon rods. on each end, use a small spring, washer, and 'hair pin'. the springs provide the clamping force and when one part breaks, you may be able to reuse other parts. OFC, you could just print the pins in, but I have zero experience with 3D printing, so I don't know how well this would work.
maybe you couldhalf power it with a rc fan to gain a bit more airspeed while diving (i know it would ruin the whole "glider" thing but it would be cool to see it fly longer!)
Changing the velocity vector of a vehicle is dependent upon the wing/body flying below the critical angle of attack. Launching these at -90* pitch is certainly causing another design requirement, reduced weight being the most important. Maybe (I don’t know if this is even possible) fitting an AOA sensor to the body and feeding that information into the telemetry would be helpful in diagnosing the instability you’re encountering. Cool project nevertheless. Actually, now that I’m thinking about it, could you use a manual-bias AOA-dependent elevator control system to your ground effect vehicle to control lift in ground effect? Is it possible that such a system could correct for artificially low AOA introduced by GE itself.
Try launching a radio control Shuttle shape from an Estes model rocket. Worked for me, after a few decades. You just told me to make it work on Otto Pilot. Game changer.
Looks like NASA got their flairs a bit more greasy than mine: ua-cam.com/video/HDET3VuT9jE/v-deo.html
One thing I noticed is that they say that they start the drop with full speed break to level out. I believe the virgin pod model does the same. ua-cam.com/video/HDET3VuT9jE/v-deo.htmlsi=aoHC2XAjqSeVzoZr&t=90
Bro please do a video building an RC version of the motor in this video >
ua-cam.com/video/juJvpleMqg4/v-deo.htmlsi=jffcn7eRH7dGxnwu
BUTTER! That just goes to show that... What does that go to show... You need more subscribers to get your R&D budget closer to NASA's!
Food for thought:! The rotor wash from the quad is causing the initial instability since it is tailwind blowing against the control surfaces, causing it to use up altitude to get stable.
makes sense. any idea how to fix it best?
longer string @@pinkpanther8427
@@pinkpanther8427 From the drone, 2 thoughts. Guide rod angled away from the drone, or towing it like a glider and releasing. Both have their own challenges.
Quick solution: Fly with a lot of forward speed during the drop
@@pinkpanther8427 Maybe two long rods to guide it and then keep the drone moving so their isn't a column of toward wash for the aircraft to be traveling through.
Making delta-wing-shaped holes in the ground is something I excel at, so here's some painfully-obtained suggestions. Highly-swept deltas have vanishingly small inertia in roll, but a load of inertia in pitch and yaw. Their tiny wingspan also provides negligible roll-damping. This is a bad dynamics situation, so if they start to tumble, it's often game-over = flat spin/frisbee. Using aileron won't help you recover; it only makes it worse. We lob little 'shuttles' piggy-back off of model rockets using a catapult: if the release isn't clean and the delta starts to corkscrew, she's a gonner.
The vertical tail on your seriously-cool 3D printed glider is way too small for the large yaw inertia, but that's an easy fix. Bear in mind that at high angle of attack, the fuselage is blanking off a lot of the flow to the tail, so folk tend to go with twin-tails.
The high-frequency roll oscillation is what highly-swept deltas do as they're stalling. I call it 'wibble'. The vortices coming off each wing are battling it out over the centre of the upper fuselage. If you don't get the nose down sharpish, then one vortex will eventually win, causing the delta to roll right over.
I've written some notes on this stuff on our website: www.aspirespace.org.uk/downloads/Winged%20rockets%20and%20boost%20gliders.pdf
very useful response!
Really great content, Rick!
lets hope Daniel sees this
Is this why we don't really see delta wing aircraft used often, if at all? What you're describing exactly matches my experience with delta wing rc planes; supremely unstable, high speed required, be extremely cautious not to stall
Thanks William, don't know about 'expert', just been doing it a long time! The thing about Daniel's brilliant vids is that we get to see exactly what's happening from many camera angles, and even from the cockpit. Watching this video lit-up so many lightbulbs: "Hey, I've seen that glider behaviour before, but never that clearly." Daniel's footage of the glider dropping off the drone was a real eye-opener.
solar autonomous plane series continue when
He’s teasing us with this
+1
Summer maybe, when there's sun in the PNW.
I will
in the summer when there is sunlight probably
Hey! Aerospace engineer here. Absolutely love your iterative approach! Do not underestimate the difficulty of what you're trying to do. There's a reason why planes aren't dropped from the sky. Basically, any "properly" balanced plane will actually resist the motion to level out. As it falls vertically and you increase the angle of attack by trying to level out, the lift increases which creates a pitch-down moment about your center of mass. Trying to level out therefore requires you to pull on the stick quite hard. This is desired for a normal aircraft in longitudinal passive stability. As your cg is likely forward because of this desire for conventional stability, since you start at 0 airpseed, you have no lift and therefore you're more of a dart than a plane for most of the flight! That is your second problem: your 0 initial airspeed and low acceleration due to having no propellor to generate thrust. This makes your lift extremely low at the start and your control surfaces are very ineffective. Remember, lift scales with the square of airspeed. Hence you're stuck in an immediate stall and you get into a spiral motion or flatspin like you see in the video. That's also why the plane with the big bolt on the bottom from the intro did so well. You get much more immediate airspeed. Excessive wing loading is bad, but too low is also bad especially for an unpowered glider! You see that with the foamy, where at some point it's more like a falling kite than a plane. Finally, the propellor wash from the drone certainly doesn't help increase stability. You're likely dealing with all kinds of vortices, which is why you see an improvement when the rod is added.
All in all not bad work at all! But you're definitely doing something that's not as straightforward as it looks!
The main reason I believe the shuttle designs don't work well is because the design of the space shuttle was made for hypersonic flight. Even while landing, the shuttle was moving very fast. Theres just not much lift in that design to get stable flight at low speeds. This is challenging stuff though. The one thing I might recommend trying is maybe a adjustable wing? So u could get more speed at a dive, and more lift while gliding... Kinda closer to an old fighter plane like the F-111 for example. Might be worth a shot!
Or try first with some traditional wing design modelling some known airplane and only try the delta wing stuff after succeeding with that. Longer steady glide path with less emphasis on the last second pull up.
The Space shuttle enters Earths atmosphere at over 17,000 mph and slows itself down through a series of flight movements to final approach at 215 mph by 3,280 to 2,800 feet above ground.
Final nose flare before touch down and arrester chute deployment is at 179mph and final roll out to a stop.
My father worked on the NASA Space shuttle. He was a mechanical engineer. He worked on the vibrations in the rocket turbo pumps and the heat shielding.
He worked all his life trying to make a circler wing aircraft. The advantage of them is the huge speed range they can fly at.
The one big trouble is "dutch roll" you can see the same effect in early lifting bodies.
That is why NASA had to add the small wings.
My father sent letters back and forth to Alexander Lip push the famous German aerospace scientist.
The father of the Delta wing on the F,102 and F-106 and all other deltas.
A brilliant man
For anyone building flat foam wings.... Add another strip of foam on top of the leading edge that is 50% chord or a bit less. And round the leading edge. This creates a KF airfoil (KFm-2) and it will fly way better.
The drop from a weather balloon at the edge of space is going to be epic! 😜
There was a guy in Canada that did this a while back and it was pretty amazing. Had an automated return system. Sadly it was lost in the mountains.
ua-cam.com/video/rpBnurznFio/v-deo.html
David Windestål also did this
That's an awesome idea !
i bet the down wash of the drones blades is messing with the shuttles center of drag. its like throwing a dart backwards.
That landing at time 7:07 was excellent. Moving the CG back sure helped.👌🖖 Looks like the 3D printed plane needs a larger vertical fin, maybe even one under the tail to help tamp down the roll oscillations. You could even add a rudder with a gyro to help.
Dream Chaser's 2017 test flight used a three-point rig that released the vehicle while in stable forward flight. Your lifting-body planes spend half their decent just getting to stable flight, so a Dream Chaser styled release might benefit your tests.
Sometimes when confronted with destructive and yet iterative testing - it can help to have some "pre-iteration" done where you map out your experiment and have several test samples ready to go on test day.
better help is a scam. Stop taking sponsorships from them. They replaced most of their professionals with chatbots that just make things worse
Be your own chatbot - is my philosophy.
Seriously. Their “professionals” were dubiously qualified in the first place.
AND they sell your data
Yeah and they also sell private information about you to advertisers
therapy is just astrology for people who don't want to admit their problems are just the consequences of their terrible life decisions.
Falling with style
One thing that would be super cool to do and very useful for a landing would be having a sensor measuring AoA. I know this because I've made the eletronics for it in the past but never managed to put it on something flying. Maybe my next plane will have it. With 3d printing capabilities, making a sensor like that would be very easy. Cheers for the great content mate!!
you start off with the drone making a lot of down wind from the prop wash so why not use some forward speed and release in the proper direction like into the wind toward the clear landing area of the field.
I've designed and built aircraft like this in the past and I found an interesting problem that you have to account for in the design you can't use a central rudder or vertical stabilizer you need to use tip rudders or tip stabilizers or that central stabilizer needs to be about seven times taller The problem is your crank arrow delta is shadowing your vertical stabilizer so you essentially have a Delta wing glider that has no vertical stabilizer at all until the teams forward fight speed the wing prevents the stabilizer from seeing air so the aircraft flies as if it has no stabilizer I build a 14 ft long version of this that was a rocket glider very similar wing design and had the same problem I would get into a flat spin and it simply would not recover because the Delta wing shadowed the stabilizer it wasn't until the aircraft inverted exposing the stabilizer to the air stream that it then straightened out and of course crashed :-)
The solution is to put tip stabilizers in the design that protrude both up and down this way no matter what orientation the aircraft is in some of the vertical stabilizer surface area is exposed to the air stream at all times this is one of the reasons why the space shuttle has such a gigantic vertical stabilizer in order to get it out of the shadow of the cranked Delta
This might also explain your role oscillation in the later model as you pulled up you were basically erasing more and more of the vertical stabilizer as you slow down and shadowed it with the wing although I'm not sure of that as long as you have forward airspeed you should be okay your solution might be as simple as putting a small stabilizer on the bottom of the fuselage so that no matter which side ends up facing the airstream on release you have some vertical stabilizer exposed to the airstream
Agree, the shuttle uses a super tall vert fin to get enough clean air. I'd start there. I bet he could test it just by taking the existing design and scabbing a piece of foamboard on up there.
@@johngoscinski1995 easier would be tip stabs. this eliminates the issue from all angles and is lower mass (lighter than a super tall central stab)
I wonder if some type of ground launch system wouldn't be better? Catapult or rocket motor? This way you are already in forward powered flight and then convert to gliding under full control?
No parabola for descent curve. A curved path of fastest descent under uniform gravity is known as the brachistochrone curve, which is a type of cycloid
True
They are controlling AOA, not position. There would need to be a controller to target position for this to be true, and it probably doesn't work because of aerodynamics
@@KnowledgePerformance7I don't really think, that it is AOA, i would say that it is pitch, but I also agree with your comment.
For the optimal path it should be based of some position system. I think that having some sort of system, that would meassure all of the flight parameter (as he mentioned in the video) and then it would compute the things to do in order to stay on the optimal path would be best, but also more challenging.
I love this type of work you do. I am an Aerospace Engineer by training and by trade, ground induced lift has always been near and dear to my heart. The Space Shuttle is an unpowered glider which is the same class as a hang glide. You don't even need a pilot's license to fly it. The shuttle's flight guidance seems counterintuitive because it is driven by an energy management system not a flight program.
You need a far bigger vertical stabilizer. That should stop the spiraling
My first thought would be to increase the vertical stabilizer. I have designed quite a few model airplanes myself, but never for this part of the flight envelope - so I may be wrong. However, this was my first thought.
100%
I'm a big fan of vertical wingtips, they look old school and for paper airplanes as a kid, seemed to help stabilize roll
I wonder if the downdraft of the lifting drone is setting it up for failure giving it less altitude to work with. I like the idea of dropping from forward flight where it starts off in a stable mode out of the gate. Probably would make things more predictable and tunable.
Rotor wash for sure is the biggest issue, you should do a short mission that moves from point A to B (then releases the plane) and have the quad move back to A.
Like 10m movement and have the plane drop at the end of that point, at least you would only have the instantaneous wash and not the built up loiter wash.
Great video. Some negative washout in the wing tip will help. Then if you can incorporate a wing tip with dihedral
Ya, I'm in agreement. Something needs to be designed into the wing/lifting body to so that it naturally seeks stability. I don't know if there is enough "wing" here to do what you suggested, but I think that's the right idea.
Would it help to have the glider much further away from the drone before the drop. That might minimize the amount of turbulent roll it experiences from the quad copter?
This type of projects is really cool. I made an rc plane and wanted to add some sort of processor to it to do some playing around with it, what sort of flight controller would you recommend? I'm thinking more of something I can program directly instead of runnig things like betaflight
Would love to see you try a skydiver / belly-flop system like the SpaceX Starship.
RCTF could team up with BPS.apace to make that happen!
try adding features to improve the low speed stalling situation... like humps in the leading edge, which funnel more air across the surface.
also, placing the antennas in front of the leading edge didn't do the airflow any good, since they cause irregular pressures
Is it just me...or does seeing the "drop" give you the willies?
ooof!
So cool though!
Keep em coming!!!!
play warthunder in first person
I work on the actual dream chaser so I'd love to see that one finalized!
I would want a small sensor that could sense air and calculate ANGLE OF ATTACK or AOA. Modulating this to near 1.00 just prior to touchdown would yield the flight you desire. But it would need a computer to sense air, direction, altitude, etc. Then you could program it for the ideal flight.
I think the Lidar might be better for this specific kind of situation. I think the differences in pressure on the altitudes where you want it to adjust are just a little bit too small for it to be accurate every time. And sometimes you would get good performance because conditions are perfect enough. Lidar doesn’t worry about air pockets in it’s sensors though
try putting some winglets on. Also you might want to sharpen the forward strake leading edge and you need more or a flat top than a rounded one for lifting bodies to work best.
try putting the vertical stabilizer on the fin. not the center. the blunt nose prevents some of the air going to the vertical fin, rendering it useless. hence why nasa put theirs on the wingtip.
Use a longer tether to stay out of more prop wash and it will start flying sooner... that release cost too much altitude with the dirty air just below the drone. You can see it clearly everytime.
Very cool.
UA-camrs really gotta stop taking money from better help
Why?
Ye y
So many spins! IMO, a larger vertical stab will help recovery from the spin more quickly. The space shuttle has a huge vert stab and rudder. Alternatively, adding winglets may accomplish the same faster recovery. Maybe try releasing while the drone is moving forward rather than in a hover. This may help reduce the initial affects from the downwash. Great videos!
Try adding a landing parachute that can also be used as a emergency parachute, Just in case The glide doesn’t really work and it goes into a tumble
I've loved watching you since you were a kid. You really maximize the possibilities of RC hobby grade equipment and open-source automation capabilities. A few small tweaks to your development goals and you could have a multi billion-dollar Defense/Defense Research company using your current skillset to shift the cost structure of short-range anti-drone air defense and front-line guided munitions. Not kidding.
Hi. Would drpping from a plane yield a better result? Seemed like downdraft from the quad was affecting it on release. Just wondering. I'm no engineer.
Maybe if it starts more horizontally it will fly better.
Hook up the launch rail at something like a 30 deg. angle to the drone's level flight.
Fix remote controlled clamp(s) on the rail that hold the glider in that position and release it from that angle.
I'm always late to the show. My only experience with gliders was a little circuit board I made for a friend who flew model gliders, it would beep a piezo if a servo movement drew the power rails below a preset limit, this way it would start making a noise before the batteries went flat.
You make enough new airplanes that it might be cool for you to make a wind tunnel to test them in and fine tune the controller. Might make for a nice build video and help get more successes out of these builds.
Add a larger tail fin to the 3d printed plane
Everyone happily taking that better help money..
You could 3d print some little kerbals as crew. Best test pilots in the business!
Watching those "landings", I feel a little Steve Austin (Bruce Peterson) would be more appropriate..
I'm here for exactly this kind of projects! MORE ITERATIONS! :D
a small solid fuel rocket engine in the back of the foam shuttle would be great along with cameras
Hey Daniel
I think your vertical stabilizer is in the wake of the delta wing during spinning and cant stabilize it. Try a downward facing one or winglets (up and down). That should help.
flat spin plane may be really fun to do pedal leaf turn stunts with an RC radio. May be one of the best ones you made.
Hmm. Are home-made wind tunnel tests an achievable idea? Since a big issue here was repeatability, maybe there's something in between CAD and real life that could provide further data. It sounds hard to build a homemade wind tunnel that can do that, but Daniel and builders like him have shown that home engineers can do all kinds of tough projects.
I've been bingeing all your videos for the past couple weeks. I hope Spring brings a bunch of new content.
As these are actively controlled putting the weight very nose heavy should be possible and still get it to 'fly'. That would then help it accelerate nose down more cleanly as you have put the drag and mass far enough apart... Of course if you or the code don't pull up at the right time it will turn into a lawn dart, or stall and then turn into lawn dart, as you will really need good airspeed to have enough control to lift the heavy nose...
Try adding some dihedral to increase stability. Also, you might try two parallel launch rods to reduce its tendency to spin when it's released.
Great video!. For some reason I started watching it after I first woke up and it turns out it was a really good way to get my brain ready to face the day. Maybe because of how you include all your experiments, not just the good ones? I'm going to try adding your videos to my morning routine and see if it helps. Thank you!
Many full size aircraft use barometric altimeters ABOVE a certain height. Radar altimeters at lower altitudes, as at a certain altitude, they lose effectiveness. Baro is not stable enough close to the ground. If you have the means, fly over a pond/body of water to a grass field, then over a road, measure the barometric pressures at various altitudes.
Sweet! Happy to see the shuttle back. I printed the last one and it has been fun.
Can you try sling-launching the 3D printed shuttle glider you show in 9:02? Like, a rubber-band powered sling to just send it.
I would entertain using PETG in place of PLA for your gliders. It’s a little more elastic and ever so slightly more dense than PLA. There might not be a whole lot of differences but it’s worth a shot.
I remember sending you a email maybe 8 or so years ago with our own foam board design. One of my fave channels mate.
I wonder if you could make the nose of the plane from some inflatable material like one of these air mattress thingies you use in pools. This should soften nose impacts to a more survivable g loading without adding too much weight.
I have a shuttle design I want to build and launch as a rocket and then have it return to base by gliding using ardupilot. The thing is, it would be starting at high speed, reaching its peak altitude before switching to auto pilot. Level flight then circle the home gps until it lands.
Something to think about:!
Full scale the release is done from a forward flying aircraft. The tailwind from the quadcopter is probably a cause of instability.
Hear me out: Downward facing catapult launcher on the drone to give the glider some initial airspeed. Maybe just something like a couple rubber bands to get it moving and give it a more consistent launch.
Did you ever make a video on the drone you’re using to do the drops? I’d be interested in seeing that.
So, one thing to consider is that the oscillation may be a result of over speed and not over tuning. You very easily could be exceeding the max speed limit of the aircraft, causing it to become unstable.
I went through some of this waaaay back experimenting with Deltas and other flying wings. First, most of those models looked like they need much taller vertical stabs. At such low Reynolds numbers and short coupling, a small vertical doesn't have the authority to keep it pointed in the right direction with all of that wing wash spiraling up at the tail. The fact they never really achieved stability shows that. CG is also super sensitive at small scale like this, so there's a lot at play. I love your videos and you do awesome work so I commend the work involved to iron out the bugs!! 👏👍
I'll come back to watch later, but I'm expecting the "Aerodynamics of a flying brick"
Too small vertical stabilizer. Try to add some winglets or larger fin. Long nose generate center of aerodynamic buoyancy in front of COG. Delta and flying wing configuration shows yaw instability as aileron swing. You can test it with xflr5. Had similar problem with one of my projects.
this is a really fun video!!! a lot of these designs you came up with look like f-zero machines
You have to imagine that these aircraft were built to carry a pilot back then, completely without an Ardupilot and computer simulations. What a hero.
This is my favourite channel on UA-cam and today I learned I want even subscribed. It just always shows up in my feed.
9:31 'reverse' the orientation of the elevon servos, and move their mass INBOARD. IMPROVE the carry/release system. use multiple to single hanging point. hoist the model at/near its cg. 9:42 don't certain control components NEED to located at the cg/c-m.? d
I think you're hitting the physical limit of actuator speed, inducing error and oscillations
Speed and lag *
Figuring out some way to simulate the planes or another way to decrease iteration time would make this project easier.
I think a small ventral fin would help with the roll oscillations.
the first lifting bodies you've made only get lift from the shockwave created when going supersonic... when it goes slower it is not a "true flight" but more of a controlled falling...
You could make it roll intentionally for the first few seconds on release, it already wants to do it, and it would give a bit of gyro stabilization.
Attach a quick release weight on a servo and release when it's stable. And throw a flag or something on the weight so you can find it later.
Could you make some kind of cone shaped shield under the quad to protect the glider from rotor wash?
The ending shot is why i just printed my m-jet sprint out of tpu so when i take it pn creeks i dont punch a hole in the hull.
How about a groundeffect solar panel and see how far you can scale it up?
11:50 pro tip: use the soccer goal nets as a net to catch the aircraft instead of having a hard landing
Have you watched when James may flew a model glider 21 miles autonomously. The glider was dropped from a helicopter but to protect it from the downdraft it was in a box about 50 feet below.
so instead of gluing it together, consider "pinning" it with carbon rods. on each end, use a small spring, washer, and 'hair pin'. the springs provide the clamping force and when one part breaks, you may be able to reuse other parts. OFC, you could just print the pins in, but I have zero experience with 3D printing, so I don't know how well this would work.
maybe you couldhalf power it with a rc fan to gain a bit more airspeed while diving (i know it would ruin the whole "glider" thing but it would be cool to see it fly longer!)
Dihedral angle in the wing is the solution for roll axis stability.
looks like you might need more vertical stabiliser area to avoid the spinning?
add an AoA vane and set a target AoA for each altitude as well as a pitch
Try to integrate a high wing with some dihedral into your next iteration.
Changing the velocity vector of a vehicle is dependent upon the wing/body flying below the critical angle of attack. Launching these at -90* pitch is certainly causing another design requirement, reduced weight being the most important. Maybe (I don’t know if this is even possible) fitting an AOA sensor to the body and feeding that information into the telemetry would be helpful in diagnosing the instability you’re encountering. Cool project nevertheless.
Actually, now that I’m thinking about it, could you use a manual-bias AOA-dependent elevator control system to your ground effect vehicle to control lift in ground effect? Is it possible that such a system could correct for artificially low AOA introduced by GE itself.
Try launching a radio control Shuttle shape from an Estes model rocket. Worked for me, after a few decades. You just told me to make it work on Otto Pilot. Game changer.
Why not connect a failsafe switch to a parachute that would help stop the craft from breaking every time something goes wrong ?
You need something like the 747 used to carry the Shuttle for your approach and landing tests.
Gravity plane: a flying wing could be conducted from Mylar. It could lift to altitude then let some gas out and glide back to home, using a FC.
Bro is bootstrapping the next Lockheed Martin and he doesn't even know it
ikr? casually developing glide bombs
@@cho4d ikr is one of dumbest sayings ever.
I never heard of light-weight PLA before, I'll have to look for that.
Did you ever consider building a wind tunnel?