Dodgy Moment, Homemade Coaxial Helicopter Learning to FLY
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- Опубліковано 12 жов 2022
- An uncomfortable moment in this video where my extended skids luckily do their job.
After a lot comments, the machine is only intended for low altitude hovering no higher than 6ft or so. In the current configuration it wouldn't be safe any higher, I could add measures to change this but no intention to do so at the moment. The machine is tethered in all tests but they are long enough not to present a danger to myself. - Наука та технологія
When you said "The grass is shorter now..." I thought it was going to a SUPER dodgy moment where the helicopter mows the lawn
😆 no thankfully not that dodgy.
To increase safety I would consider bolting plastic balls to the end of your landing gear outriggers. This will help prevent a dig in if you a forced to land with sideways motion. Spherical toilet cistern balls might do it. Good effort so far.👍
Thanks for this, I hadn't thought of cistern balls, good idea. Light weight and cheap. Will think about how to mount them so they don't come off. Cheers
While I agree that the outrigger tips could pose a problem, I was thinking that the outriggers need not be level with the base of the copter. If the outrigger tips were raised up by 5 to 10 degrees from the base, they would be much less prone to digging in from slight angle sideways helicopter motions, but could still protect against very high angle tipovers.
That’s the exact same things I used when I was learning to fly a model heli
@@kitchencone Yeah, but having stabby things pointing up isn't a great idea
@@mikejj101 Yep same here, definitely helps to prevent dig ins, which in a model RC copter is extremely costly (certainly back when i was doing it), where as in real life could be deadly.
It appears that you are giving input to the pedals with your whole leg. This will result in large pilot induced inputs to your cyclic because the height of your knee will keep changing. You should be pivoting at the ankle and inputting with toes only. You heels need to be supported and stationary if they are not now.
Great observation. I will see if I can alter this, I would have to increase the ratio of pedal movement to fin deflection but I think this would be a good idea anyway. I'm moving the pedals way more than a Robinson.
Oh wow, great obs! You may have just saved this guy's life. No kidding! Cramping could occur with the set-up, too, and a charlie horse is not a good thing while flying this!
Whilst I agree it is difficult to prevent unintended pedal inputs if the heal doesn’t have a rest, rudder pedals are connected to each other in opposite sense. Any motion imparted to the foot due to the knee moving vertically will apply to both legs. As you can’t push both rudder pedals at the same time, this shouldn’t be an issue. I can see the benefit of using the knee pad to steady the right arm though, although if this is necessary to be able to fly I think you have a bigger problem to solve.
@@gillfitzpatrick7894 I am not sure the reason you have brought up both legs and counter-operating pedals. But yes, an push input from the left leg WILL impart a right pedal push on the right leg causing a cyclic input. What is the bigger problem you have mentioned?
Gotta accept the lag, especially when torque controls yaw, not ona the tail boom parasites. 👍
I think the natural instinct to bring it down is the correct action for a novice pilot in a homemade helicopter. Anyway good to see everything is fine and ready to proceed without any issues. Congratulations on your achievement so far.
Geezer really made a little copter, hats off to you sir!
I have never seen a more terrifying title for a video. You have earned a subscriber. Please don't die building this machine!!!!
Very interesting form for a randomised suicide machine!
Most impressive. 10/10.
Isn't that called the compliment sandwich ?
that looks like a helluva great way to get to the line of way too sketchy and way too fun, what an cool way to spend your time and effort, love it!
Absolutely well done!!! It's great to see a true helicopter without all the highly complex swash plate systems. Looking farward to your next flight!!
Good morning from Washington state USA, you get better keep up Good control.👍👍🙏🙏
Good job! It looks so stable compared to earlier videos. I like how you take everything into account and have safety first. Looking forward to the next video. As Scott Manley always says: fly safe!
The wide skids are flexing, but have worked correctly when required. Congratulations on going back up!
Yes thankfully they worked well, no way I could have even got this far without them. In time I will gradually reduce the length but certainly not yet. 👌
That was a bit scary. I can only imagine how you were feeling at that time. Really enjoying the video and seeing your progress, safety always.
Thank you. Yes it wasn't nice and was a wake up call to what can happen but I think next time I won't reduce the power, that was my mistake.
Hovering is critical, but 1) having in mind what you intend to do prior to going airborn is important, and 2) you'll find greater confidence and characteristics once in forward flight.
OMG... reminds me of learning to fly RC helis back in the 80's... same wide landing gear, same tentative hovering. Only I wasn't in it!
😉 It's surprising the similarities between RC and full scale. but yes being in it is definitely different.
@@Ben-Dixey Yes... I hopped into a Schweitzer 269 and was flying it completely within 10 minutes. I could even hover in ground effect. The instructor wasn't fooled... "You fly RC, don't you?" :) TOO expensive for fun flight, though.
You are obviously one of those rare naturally gifted people who can just do it. I fly RC and didn't pick up flying the real thing anything like you describe, it''s taken a long time but I have no doubt the RC experience helped. As you know the cyclic movements are very similar but recognizing the aircraft attitude looking out the window is something different. On the plus side controls on the full scale are never reversed.
Great to see you are making positive progress, it wont be too long before you are hovering without thinking about it.
Your power plant will ultimately hold you back in its present form. Take care and thank you for posting
Great video! Love hearing your process and theories as you film! Top notch!
I litteraly had dreams as a child of building a helicopter from a scrapyard and feeling so free whilst piloting it. Still looks unreal :)
I'm starting the build of a Hexacopter manned drone and, even though our projects are completely different, I'm getting a lot of inspiration from you. Congratulations!
Sounds Interesting, are you going electric ? I would like a manned drone.
@@Ben-Dixey Yes, electric. I'm still thinking about making a channel on youtube or not, but if you are interested I would be glad to share the progress with you.
@@flaviovianna4889 Make a channel on YT! I’d love to watch your progress! If you’re inventing new tech though, I could see why you’d want to keep it private.
lols I help develop the best racing drone software available and fly racing drones and.. NO THANK YOU... unless you like human sushi 🤔
@@flaviovianna4889 Yes I would be interested for sure. btdixey@hotmail.com or YT channel would be great
The hover is the hardest part! Awesome build!!!
Specially when low to the ground
Minutes instead of seconds, awesome. You do realise that hovering at one foot is a lot harder than hovering at five feet.
I've been told that and have experienced the difference between 6^ and 3ft I can imagine 5 feet is even better. Going 5ft high takes some nerve at this stage which is why it hasn't been attempted. Assuming that is it has the performance to go that high that is.
Bloody brilliant video and great progress, love it. Thankyou from Rome👍✌️🇬🇧
Loving your approach to it all mate very disciplined and methodical, well done.
Thanks Jim, you could fly this thing with your eyes closed. 😀
It is amazing, what you have achieved. I got my heli license in 1984. I was once quite a proficient pilot, with 5 type ratings, but these skills have now atrophied, so I have stopped flying helis and have bought a small fixed-wind a/c with a friend. I think you fly it well - and it seems quite stable. On the question of the upset, putting it on the ground is the safer route. When you are hovering a low as this, there is a risk of lateral motion resulting in a skid strike. Whilst I appreciate that you have skid extensions, you still have a risk of a dynamic rollover if part of the skids gets stuck in the ground and you were to increase rotor thrust. Good luck!
Hi and thanks for the comment. Good to know your thoughts on situation. I've added balls to the ends of the skids since this video. Will help avoid a skid dig in which of course would be potentially disastrous. I'm pretty sure on a calmer day this wouldn't have even happened. Enjoy your fixed wing 👍
I'm not a helicopter pilot, but I worked for Mike Hynes, Brantly Helicopter, as a machinist, and all the pictures and movies of B2 test show Frank Erickson filing chained to the ground. There was no question about Frank's ability to fly helicopters. He had been doing this as long as anyone. The wind or whirlwind in Frederick, Oklahoma, could wad up a B2 in seconds.
Hovering that close to the ground is dangerous. No one has fast enough reflexes to counteract errors and accidents that happen that fast. Tie your rig down on short chains so your skids don't dig in, and stick your rotors & head in the dirt. At least bend the ends of the skids up and put aluminum balls on the ends of them.
I don't think the actions of a rigidly mounted helicopter rotor with conventional cyclic and collective controls apply to rigid counter-rotating blades on a tilting shaft.
Good Luck!
Hi, Good to hear from someone who made Brantly parts, I don't know a lot about them apart from the ice cream cone shaped fuselage. After a bit of research it seems a well respected and made machine. Great sound from watching some YT videos. I like the three bladed design, high inertia rotor system for good autorotation and smoother ride.
I agree about the dangers of hovering close to the ground hence the reason for the long poles which do have the ends bent up to prevent them digging in. Balls on the end I'm open to.
I started off with short tethers to ground anchors and they were needed in the beginning. After gradually extending their length they were starting to be a hazard and preventing the process of learning to hover. I still have them now but they are 100ft long and serve no purpose other than allowing me to show the videos. The 5m long poles have been great at gradually allowing me to gain altitude in safety and learn the skill of hovering. I guess now I'm getting to higher altitudes (3ft) things have the potential for rougher harder landings if things get out of control. The rough landing in the clip has been the worst over the last 6 months testing and it's also been the windiest conditions I have dared test in. Back to calm conditions for me now.
Wow i am sincerely glad seeing you flying more with your machine.
Good morning. I am enjoying watching your progress. I do have a few questions/suggestions/observations for your consideration.
1 MARK THE LIMIT/RADIUS OF YOUR TETHER. Painted circle or tufts of surveyors tape on pins. Movable and re-usable. There is a danger of reaching the end of your tether and causing you to fight against it in a recovery. I have seen a number of videos with a tethered helo that would have safely flown away get destroyed due to being tethered. 2 CAN YOU ADJUST THE SENSITIVITY OF YOUR CONTROL STICK? I know there is only so much space between your knees. But a small amount of stick input seems to upset your helo. 3 WIND SHELTER. I under stand the logic of hiding behind the tree and fence line, however the wind turbulence behind the wind break may be more harm than benefit. You may really be better off in an open field with straight and consist wind patterns. I know good days to fly are few but if 5 mph is your safe limit then obey that until your skills improve. 4 CAN THE HELO REMAIN STEADY WITHOUT INPUT. Is the mast head in balance? Are you constantly having to provide correction to the helo? Is there any vibration? Have or can you pitch track your rotor(s)? 5 DO YOU HAVE THE SKILLS TO FLY A HELO? I know that as I have aged (60) I do not do things as well as when I was younger. It is one thing to learn a new skill and strive to do something new. Is it worth dying for? Professionals crash helo's on a regular basis. I watch Dan Gryder Probable Cause on UA-cam. In the USA we are loosing one General Aviation aircraft a day this year. He has a great channel. Lots to learn. STAY SAFE. Regards Dudley
Thanks for the input. The marked circle would be an excellent idea, it's easy to loose track of how far you have moved. The tether going tight would be disastrous. Given the choice I would ditch it but I can't do that. The tethers are 100ft long so I would have to go half way across the field for them to get tight but certainly good to mark where that is. I did reduce the sensitivity slightly of the controls previously but my thoughts are now that it needs to be more sensitive, more like the R22 I had a lesson in. The cyclic on that was twice as sensitive to mine I would say. I think less travel on the cyclic would mean faster corrections making it easier to keep up but I could be wrong, it's difficult to say what is for the best.
@@Ben-Dixey Thank you for the reply. My observation on the control input is limited to what you post in your videos. The R22 sensitivity may be a function/need of the rotor system. Stay Safe. My helo experience is very limited, but I recall the pilots did not have to have input to the controls at power just before flight/lift off. IE the rotor seemed to be balanced.
I'm 51 yrs old so forgive me when I say, COOOOOOOOOOL! I want one, I want to build one, I want to fly one. WOW. I have no means to do so so but WOW!! Great video, really interesting and inspiring! I do have an old pallet out side.....I wonder.....
Amazing work!!!
keep going mate I'm love you sheer will and hard woks!! great machine 😁
Agree that it would have been best to keep it airborne certainly until you’d stopped the lateral drift. This experience will give you the confidence to keep it up. This was almost a rollover crash, but luckily your bars saved the day. After all that’s what they’re for.
I guess panicked pilots do the wrong things. I won't be letting off the throttle next time. Perhaps it can be likened to drifting in a front wheel drive car, the back steps out and if you let off the throttle things get way worse. Keep it pinned and you will be fine, it's just keeping your nerve.
Amazing progress! It won’t be long, until you’ve got it all sorted out-by others’ suggestions, your engineering skills and trial and error😊🎉
Glad you've progressed this far 🙂 I would suggest bending the cyclic back about 10 degrees, so your hand and arm can be more relaxed. For the best control, you should be able to control the cyclic by your thumb and index finger - ONLY. Gentle movements are best. If you 'think' about moving in a specific direction, your hand will automatically move, slightly, in that direction. Currently, you're still 'over-controlling' the craft. Gentle inputs are required. Again, Great Work! 🙂
Thanks for you're input. 👍👌
I always find it interesting that heli pilots have to learn to do the most difficult and scary thing first. Hover in ground effect, which is by far the least stable condition.
Generally forward flight in any rotorcraft is easier, more stable, and uses less power, but yes you gotta stop, or at least slow to land. Do keep in mind that if you learn to "hover" with a constant headwind, you're not really learning to hover. You're just flying forward at the wind speed.
Makes perfect sense to me, in the next video I experience this constant head wind stabilising effect. I would like to try it in a wind tunnel.
Love what you've done with the skids. Smart to go that large when testing (or even later). I would probably consider making the curved tips a bit bigger: you're not far from getting a tip stuck in the ground in this video.
Thanks. I've just added plastic balls to the bent up ends and have just tried it. Think I'm happier with more clearance. I could bend up the ends a bit more anyway, it wouldn't hurt.
@@Ben-Dixey If you look at it like a machine made to skid, then I would say that a long progressive curve would be ideal (reduced friction) much like the shape of modern skis (rocker), which is also more or less what a lot of helicopters are equipped with. Even better would be to cover the bottom with PTFE or polyethylene but that's pushing a bit :) Amazing effort anyway.
You could just run back and forth across a busy motorway instead😁 you have a lot of pioneer guts.
the top section of your coax-heli is so damn "wobbly".....when you hit the grass and do skid sidewards = kind of scary to me..... = whow..... ! ! // second: I am happy that you are no foul and you do judge your actuell skills very well / thanks for sharing the video
Later in the video I show that the whole rotor mast tilts on hinges for control, it's not like any other helicopter you would have seen.
Hovering in the gound effect is much harder, looks good tho, respect
Had just seen your video recommend, I'm an avid rc heli guy only. So I'm afraid i can offer no info or advice. What i can say is that your counter rotating mini chopper is pretty dam cool man! Nice job!!!
Thanks, there's a lot of information to be gained from flying rc, some of the people that just fly rc have commented on all sorts of flying characteristics that I was surprised could be determined from the models.
Part 8: From one professional mechanical engineer to another... you could [still] shave 6 months off your product development cycle time by using an electric motor. For shorter tests - you won't even need a battery. Overall though, excellent work!!! Great videos!!! (just envision... no more metallurgy, "should I use a new steel alloy", HP vs. power responsiveness rabbit holes, bearings, cooling pumps, vibrations, lubrication, fuel management, rpm/torque control concerns and about 50-100 more things) Electric motors are 99% mechanical engineering anyway - only those pesky, invisible things like electrons and magnetic fields are EE, Lol. Huge congrats on overall work!
Hi, and thanks for the comment. As you say it would have been so much easier with electric motors, I could have had two motors spinning in opposite directions which would have simplified the rotor reversing add into that yaw control via differential rotor speed. ( no tail vanes required ). plus all the things you mentioned. It did of course cross my mind in the beginning, there were two things stopping me cost and flight time. The electric setup was way too much money for someone who didn't know if they could even build a helicopter that could fly. It's something I would seriously consider for the future but it's still very expensive, I suspect in time the cost will come down or there will be other second hand vehicles you could buy and utilize the components.
@@Ben-Dixey Hi, and great to hear back from you. The rationale of flight time is right on. However, I didn't realize that electric motors and peripherals were more costly? I may try to contact a coaxial builder, there's are a couple in southwest Ohio, near me. There were a couple of fixed wing guys from this area, but that was a hundred years ago or so. Not sure if the family is still into it.
@@stevieathome4942 Yes, I priced up the battery's at the time which came to £10k. I'm sure they are much cheaper now and better performing for there weight. Pascal Chretien built an electric version quite a while ago. seemed to work well.
Not a real Helicopter pilot however I fly RC Helicopters, when hovering close to the ground you have ground effects. In Ground Effect (IGE) is a condition where the downwash of air from the main rotor is able to react with a hard surface (the ground), and give a useful reaction to the helicopter in the form of more lift force available with less engine power required. When I first started learning I had a dude tell me get higher up away from the ground effects and it's much easer for hovering.
Thanks and yes I have felt the difference in stability higher up, when I'm feeling confident I will increase altitude but haven't been any higher than 3 ft to date. It takes some nerve to go higher and it will gradually increase as confidence does. It's the old catch 22 you need to go higher to make it easier to learn but you need a higher level of skill to advance to higher altitudes . Dual instruction is the easiest and safest way
@@Ben-Dixey Once you've gained the confidence everything will fall in place, you will fly higher and start going places. I fly a Cessna 172 IRL and it took me about a year till it all fell into place. I look forward to more videos.
Awesome progress. You only have to rewind a few vid’s to see the difference. Wont be long before you look down and see your hands and feet flying by themselves. It’s a weird moment. As you say though, all that does is provide a little more brain capacity to learn the next skill. Seems an endless journey for a while but you’re definitely doing everything right, slow and steady wins the day. Thoroughly impressed sir.
Thanks for the comment Paul. I Would say learning to hover the helicopter has been as hard as building one. I knew it would be difficult but not this difficult. Patience is tested to the limit, but things are starting to click, just very slowly. I've actually got it easier with the coaxial, no torque reaction and no managing of power with collective. You can see why dual instruction is thought to be the only way.
@@Ben-Dixey It sounds silly but you may try singing or humming a tune as you practice, moving the focus of your mind away from the immediate intricacies of the coordination exercise can keep you from tensing up and free up your automatic responses to start working. Just a thought. Live what you're doing, when I was a lad I started work on designing a glider, it was the one time my father said "NO, you ain't doing this!" ...Rather glad he did as I was running blind with one old book on gliders to go from. :-)
@@JesseP.Watson sorry, didn't see this message, an interesting suggestion to try. Thanks
Amazing project, i'm very impressed. Good luck and best regards from the Netherlands
I’m not going to pretend to know anything about the intricacies of a machine like this, but be careful.
Wind sock evidence seems to suggest that lateral movement was probably caused by a gust BUT - perhaps not. Depending on what the TRUE root cause was for that roll . . . . your decision to land immediately MAY have saved the day. Until you are certain of the root cause, I am tentative about your thought to push it harder next time. 1000 Hours in the air in hang and paragliders - - - I've always been rewarded with a decision to get out of the air when conditions were deemed too treacherous or UNCERTAIN. The decision to "push further" was only made when conditions and attitude were as anticipated and fully understood - irrespective of how I might"feel". There's a difference between experiencing (for example) high G's for the first time and "pushing" through it - - - and pushing harder into an uncertain regime.
I have read about the situations in which you speak of and I can understand your reason for mentioning it. I guess it depends on whether I could have rescued the situation or made it a lot worse. I have had smaller instances of this where I rescued it and didn't try landing travelling sideways. I think I would have rescued the roll back to a controlled hover on this occasion had I not descended. I suppose it's about judging your own levels of competence but in a split second. This time all was ok but it was dodgy. I'm not going to fly in wind that gusty until a greater level of ability has been achieved.
Not sure what I admire more, your bravery or your machining skills, I’m loving it, I highly recommend you try flying a model helicopter it will definitely help your understanding of affects of inputs/ power/ ground effect etc. dunno how far you are but your welcome to use one of mine.
Thank you
It's the damn RUST MINI!
I learned to fly an rc helicopter and had the same worries but on less of a scale. My only worry was paying for new rotors. My hat goes off to you. My penny's worth of advice is maybe shorten the stick a touch to make it more responsive and maybe bring it closer to your body. You are on a winner here.
Practice makes perfect. Good luck to you and your chopper.
Thank you, I have put the shorten the cyclic stick on the to do list as I completely agree. It's a lot less sensitive than the R22 and this should improve matters.
New rotors (only) huh? haha
hello mate, may I suggest pointing your nose into the wind, increases the wind-cocking effect and stabilizes an IGE hover. Please also extend the front and rear skids, or extend the bent up ends to avoid a dynamic rollover. Also, would pay to maybe get one or 2 hours in a Robinson r22 to learn the basics of helicopter control as it is the most unstable helicopter out there. aside from that decent hovering, have seen worse in real helicopters in people with 10hours
Hi and thanks for input, great thoughts. Interesting to know that the R22 is the most unstable bird out there. In the previous video I did some training in an R22 it was a great experience and plan to do more.
Good job, stay focus and take your time.
Thank you, I will 👍
Good luck hope you don't get hurt looks like your getting there.
Collective is about mass. It can be changed very quickly, but the whole head can’t move that quick. It’s like live axel vs independent suspension. Equally, I thought it flew very well :o) it’s going to be jumpy when the whol thing is so light.
I expected the same, I thought the movement of the mast would be hard and slow and I might even need hydraulics. However it's incredibly light in flight, almost as light and responsive as a Robinson. Not quite the same but very similar. Not what I expected at all.
Brilliant, just brilliant
Learning to fly RC helicopters in the early 90's cost me a whole lot of money because wrecked em almost every single time they came off the ground so watching you do that while sitting in the actual egg beater with seamingly no protection terrifies me to no end. You are so much braver than I, that's for sure.
You seem level headed though so I'm sure you'll figure it out and be flying that thing around like a Ferrari in little time.
One suggestion though if I may? Some round balls at the end of your trainers so that the risk of them digging in and rolling over would be reduced.
Just looking at purchasing some balls. The ends of the tubes are bent up though.
US Army Helicopter aviator says... "Study dynamic rollover".
Those long outriggers scare me.
So far they have prevented a few dynamic roll overs. I think as long as they can't dig in they are the safe. Dual instruction is even safer though.
Man watching this there are only two outcomes. You fly successfully or you get hurt bad. There is no in between.
I would recommend a heavy cable or chain directly under the C of G to calm pitch and roll down a bit, similar to an early Lama R.C. umbilical chord model.
Your Mother never told you that if we were meant to fly we'd be born with wings did she.
Why are you screwing with Physics - you can learn all you need to know about Flight by picking up a rock and dropping it 😂
Loved the video and have watched a few to know the work you put into the counter-rotating Anti- Ejector Seat device.
It is wonderful that you are documenting your progress.
I think a lot of your instability issues are from being in ground effect, the aircraft will constantly try to "fall off the bubble" of compressed air that is under it.
If you ever tried to balance a magnet floating over another magnet with opposing north poles you will know what I mean.
Once you get more than a full rotor width between the rotors and the ground you should be pretty much out of ground effect. So you need another 5 to 7 feet of altitude above this test I think. Anyway, good luck! 🙂
Thank you. I am expecting it to be easier higher up I just don't have the confidence to try it yet. I don't have the skill to correct every situation, for instance two controls at a time and can correct simultaneously but if suddenly all three controls needed my input at the same time then I might get overworked and get one wrong. It's catch 22, I have to practise in the turbulent air for now. Looking forward to being able to go higher and hopefully progressing much faster.
@@Ben-Dixey .. yeah for sure it must be a scary experience. Maybe over some test runs you can refine the controls and control surfaces etc.
Please be safe friend! 🙂
Good job.,,👍👍👍
This is awesome
Wow! Impressive.
Brave man!
So I'm thinking about a possible side effect of directly pushing the rotors off angle, versus using cyclic.
With cyclic, aerodynamic forces change the rotor angle immediately without a counter-force on the aircraft body. The rotors fly themselves into their new orientation, and the body only reacts to the change in thrust angle.
But you're directly pushing the rotors off angle, and while they may counter each other's precession, you still have inertia to overcome so as you push them off angle one way there is an immediate counter-force applied to the aircraft.
e.g. In order to quickly tilt the rotors to the right, there must be a reactive force on the body, tilting it a little to the left.
But what happens when you stop pushing on the rotor and hold the stick in its new position? Gravity will pull the aircraft body back straight down and unless you counter that on the stick, it'll cause the rotor to tilt a little more to the right, which is then followed by more tilt to the right as the thrust line starts pulling on the top of the aircraft, so a little commanded right, becomes a little more right, and then a little more right, which is a bit of a positive feedback loop.
Let's go back to the cyclic heli for a sec.
If you're level, and you quickly tilt the rotor to the right, the body initially stays vertical, then as the thrust angle changes, and starts to pull the the top of the aircraft right, it'll cause the aircraft body to lean a little bit right, but then gravity will try to pull it down straight again (causing a little left rotation), and if you hold the stick still, that will cause the rotor angle
to also return back a little left, which is a negative feedback condition.
I suspect the difference is subtle, but most noticeable while trying to hover in turbulent conditions.
My hypothesis is that you may need to think about giving a command and then taking it back a little bit (moreso even than you would with a normal cyclic heli).
Very Interesting comment and I'm going to have to think about what's been said. There is one bit of information I would like to add, I believe aerodynamic forces help to tilt the rotor by cyclic angle of attack changes. The same as a gyrocopter where moving the cyclic is very easy. The difference with my coaxial is the top rotor being so far away from the hinge. This means some force will be needed to move the rotor laterally which causes the airframe to tilt as you mentioned. I can feel the cyclic stick wanting to return to centre after an input which I think confirms that some weight shift is indeed going on.
I like the gun sight. 😆
Bell 47 has the radiator immediately behind the cab, between the cab and the engine. There is no airflow induced by the rotors there. There is a shroud which forces the fan driven air through the radiator, it cannot escape out the sides. I would start with that, minor alteration and virtually no weight gain. Was the Robinson time hovering of assistance? Love your friends reaction.
Good plan, thank you 👍 as you say the shroud is virtually free cooling improvement and easy to install.
The R22 did help in a similar way flying at home does but with 20minutes hovering in the R22 that is more like two days flying at home because I can only do 1 minute 20 at a time. I might do 10 runs in a day if I'm lucky. What was really great was to reacquaint myself with the sensitivity of the 22 and compare it with the coaxial. As a result I'm going to make some of the controls more sensitive. The instructor was also great pointing out things I can Improve on. Him telling me I was behind the helicopter and needed to speed up the corrections was super, it's not something I wound figure out for myself very quickly.
Flying is really something else
I am very glad to see that you are being safe & cautious as all possible during wind & breezy conditions & that you are not rushing anything at all. You're comming right along in improving your skills. Nicely done. I do have a question for you. . . . ." is your co-axial helicopter set up with autorotation capabilities?" Thankya for sharing with us!Fly safe😃👍🏼👍🏼👍🏼
Hi, cheers for the comment, no autorotation is possible in the current configuration. Most helicopters need 50-75 ft to transition into autorotation this machine won't be flown above a few feet. An electric back up system could be added to proceed to higher altitudes. The Hungaro copter is developing such a system. If I intended to fly above 50ft then collective pitch would then be required.
@@Ben-Dixey okie dokie & thankya for the reply back. would like to see this setup as a collective set up as well as autorotation. Happy flying & keep up the good work!
YOURE LIVING THE DREAM, MY DREAM, WOW
Thanks 😉😉
Вы молодец у вас получилось. не думали поставить электронный гироскоп для удержания горизонта.
Thanks, I wanted to learn the skill of piloting but electric flight controls could be an interesting future addition.
Amazing! Just wondering if the slight flexing in the area of the assembly above the cabin is expected, or if the mounting may not quite be rigid enough? Could add a bit of unpredictability to the behaviour of the craft?
Thanks. When you say flexing, are you aware the rotors tilt on hinges? It's not like other helicopters in how it's controlled.
From the look of your field and where you are situated, it is possible you are in a turbulent area with that wind direction.
Not sure what terrain causes turbulent air, we are around the top of rolling hillside with a sea view. I'd say it was generally turbulent air at a guess.
Ficou muito bom seu helicóptero, parabéns!!!
Thank you. 🙂
Eu sou do Brasil, e sou agricultor aqui , estou querendo fazer um desses sem piloto para pulverização agrícola controlada por GPS, eu tenho um amplo conhecimento em drone e aeromodelo a anos e queria fazer um aeromodelo gigante, eu uso a placa controladora pixhawk, você conhece?
My language os portuguese
Well that's sounds like an interesting project. How much liquid would you need to carry to be of use ? I'm 95kg which would roughly equate to 95ltrs but you would need to have the tanks on the CG line to Maintain balance. I don't know anything about the radio control system needed.
o maior drone hoje é o dji Agras, ele suporta 50 litros, mas se conseguir levar 100 litros seria melhor, porém o preço dele pra mim é de 50,000.00 dólar, e as baterias são caríssimas para substituir, pois elas carregam umas 200 vezes apenas, tornando o custo hectare inviável, você tem Instagram, Facebook?
Might want to try longer rotor blades vice collective and cyclic pitch which would be very difficult to build.
To verify that cooling efficiency is actually the limiting factor here, i guess you can quickly rig a gravity fed water sprinkler on the radiator in order to add a good measure of evaporative cooling to the system. I reckon for a couple minutes of flight time a simple water bottle ziptied to the frame plus a few plastic tubes should simulate a bigger radiator/fan and cooling efficiency should go way up.
Interesting idea, I hadn't thought of that, I don't see why it wouldn't work. I suppose it's like adding some cold water to system?
@btd1982 yeah, should have a similar effect, without having a external system feeding in cold water. It's commonly used to dramatically increase intercooler heat exchanger efficiency, even quick and dirty setups should have a measurable effect ua-cam.com/video/ZtUfgA_mtDA/v-deo.html
@@Ben-Dixey evap cooling works great, highly used on intercoolers.
Subscribed!
I'm going to subscribe to see how you progress.
IIRC, the reason non-coaxial helos don't use the pivoting shaft design is because it is so easy to chop the tail boom off.. Also, when you transition to forward flight do some reasearch on "vortex-ring state" and try to intuit the mitigation before you start forward flight testing.
Yes Could be a reason, though I would have expected the same rotor angles in a rotor with cyclic blade feathering. VRS I believe you have to be descending into your own downwash. The machine won't be flown above a few feet.
@@Ben-Dixey ok, if you aren't going to be out of ground effect then VRS is probably less of an issue. I also went and checked on the Robinson R22 and it is listed as having a "tettring hing" plus others and I think that is part of the reason for the very tall rotor mast compared to more traditional helos.. But don't take my word, I have be wrong many times in the past.
Yes the R22 has a tri hinge rotor head, patented by the company. It's a controversial rotor head and has been blamed for a lot of accidents. The height of the mast being so high could well be for extra clearance with the rotor head being capable of extra flapping. Though I was told that the height was to do with providing extra stability in hovering.
When You fall off a Horse and get right back on it's because you didn't get all chopped up in little itzy bitzy pieces by the horse's rotor blades. Very Cool Machine.
I think one thing working against you when compared to the typical swash plate system is that there is a lot more momentum in the system because you're moving quite a lot of mass around which is why you're not able to make tiny adjustments and you're getting more side to side oscillation of the whole helicopter.
I think that's true, moving the top rotor laterally would cause the helicopter to be controlled more via weight shift than traditional control methods.
Mad lad!
Nice work mate, from another John. With regards to cooling and your mention of 'increased flow', increasing the flow can actually reduce the cooling effects. If the coolant flows too quickly through an engine it does not get a chance to absorb the heat, sounds strange but thermal conductivity takes time, like holding your finger over a candle vs flashing your finger past. Not sure how you are monitoring the temperature and if you are referring to engine heat or radiator heat. Could you have a aluminium or copper pipe that loops around the gearbox with cooling fins connected with flexible hose to make more use of the down wash/turbulant air or use the large sprocket spokes as the cooling fan. or turn your yaw flaps into an airfoil shape and also a heat exchanger. You'll figure it out. Glad you are having fun and taking it one step at a time.
Thanks John 👍
Cheers for this, I was thinking you could run a water pump too fast but in reading about it, the general opinion is you can't. It just means the temperature drop across the radiator is smaller and the whole system remains at a more consistent temperature. I might be wrong and you could be right, I don't know.
The idea to run coolant pipes in the downwash could be explored and I like the airfoil shape tail fins, I'm sure it would be more effective and would require less deflection angles ? The temperature gauge is taking readings from the top of the head, being the last place hot water exits it should be the hottest ?
@@Ben-Dixey If you did a close up of the engine and cooling system it may be easier to see, but I'm sure you will figure it out.
@@Ben-Dixey Formula 1 TURBO Era | 800HP Toleman-Hart TG183B [TECH TALK] search that on youtube and listen from 5 minutes.
@@chippyjohn1 That's interesting about the over cooling via too high a coolant flow rate. There is however more people online that would disagree than agree with that. I'm still not sure which is correct.
If that was a truly a cold start to full power in a short period of time as it appeared, I'd say you're looking at engine problems in the near future.
No, I warm up the engine on the first run, then the water temp is 40-50degrees before each test run.
Get a ballistic para shoot and get above ground effect. Seems like that low hover is a good way to crash. Have you tried a simulator like DCS:World? You could get it up and running for a couple hundred Dollars with most of the cost being a stick and rudders. DCS is free and you could "try out" the modules for free for 2 weeks. Even Air Force pilots have to master the simulator first. This looked terrifying. Good luck man I'm subbing. Cool build.
Thanks for your input. I looked into the simulator pedals and Joystick ect and did bid on a set that was reasonably priced. Didn't win it but will look again, with the winter weather coming it would be good to practise. A fellow home builder Hooked up control pots to his actual Heli, which is another option.
Morning has less wind as we know
Much improved flying!
It almost seems like you don't have enough power or it's just too heavy have you tested to see how much lifting Force the helicopter is capable of at full throttle/pitch?
Yeah I think as far as gauging your fan efficiency versus horsepower laws versus lift a simple way to connect a force gauge to the ground and try to take off at maximum power would be a great simple way to verify changes
Hi, i haven't tried full throttle on the new blade pitch setting yet so don't know how high it can now climb. I don't know what pitch setting is going to give the most lift either but I'm expecting 7 degrees will be somewhere close. Currently bottom rotor is 6.5 and top rotor is 5.5 degrees. Take off weight is around 250kg and the expected mtow is around 300kg, comparing other coaxial's.
Yes is could be done and it would be nice to know some figures.
Never did man sized but I have flown plenty of RC copters, one of the primary benafits to use of collective pitch and swash is wind gusting and handlining is a lot better, as is any harder change in direction, one issue you will find is when you are moving forward in coaxial and go to come to a stop, your going to gain altitude, and its going to be hard to counter that with lower power as that will introduce some fluttering, will be a little tricky, so I suspect you will need to keep movements smooth and slow to balance that.
It will be interesting investigating that for myself. Have a look a the Nolan coaxial on YT I think they did some quick stops in their promotion video.
Need more rotational speed from the blades but the motor is over revving.
An increased final drive ratio on those blades might help.
The engine is at 5500rpm , operational range of the engine is 5500-6500rpm. I can add more pitch to the blades for more lift.
I guess also it has a high center of gravity with the drive design? Increasing momentum of a dynamic roll over.
Well yes, the drive is quite heavy and high up but the engine and pilot position is quite low. If you look at the sch2a coaxial helicopter it has its engine up by the drive. That would be much worse than mine with regards to dynamic roll over. However I think it could be easier to control in the air, perhaps reducing control latency. I haven't got my head around the effects of the vertical position of CG on helicopters in flight.
@@Ben-Dixey Non the less your work is impressive! Keep it up!
Thanks 😊👌
❤👌 Speechless
Would you consider extending the vertical fins further back and increasing their size? Might help dampen rapid yaw.
Hi, Would that dampen or increase the rapid yaw ?
well you are still making progress mate 😀 keep at it. when you put it down after the oopsey moment i did notice the mast and the square, is it a gearbox? appearing to articulate and wobble compared to the air frame. Could that be adding some 'deadband' mushyness to to pitch and roll? Coul
pled pendulms etc. just a thought.🙂 Al edit: I see you comment on this, some sort of damping perhaps to slow the double pendulum interfering with control inputs.
Possibly a damper could be added which only took affect in the event of a rough landing. It would have to be fairly free moving otherwise. The R22 has a cyclic friction adjustment to make the control harder to move. I don't think it's necessary but I guess it comes down to pilot preference.
@@Ben-Dixey Well i'm sitting here comfy and 'experting' 😄. Your project BTD, so go where you think you need to eh 😉. Keep up the good work, baby steps n that, you'll get there...
Jumbo RC Helicopter Head Ahhh, I like it.
A shorter stick would help a lot. Kinda sucks flying in ground effect too..
I think you're right I plan to reduce the stick length. 👍 ground effect isn't helping
ground effect flying always looks like just that , sat on the top of a bubble trying to stay on top
👍
This is the fist video of yours I've seen an this could be something you've already tried, but have you considered putting actual dampers on the pitch/roll stick and/or what it connects to on the head? I kind of also wonder how much slop there is in the control stick and if that's a problem. Dampers with a spring return might take the load off of you having to manually hold it steady. I know all of that adds weight but it shouldn't add much complexity or cost.
Hi. Yes dampers have been suggested I'm not convinced they are the right thing to add. There is a tiny bit of play in the controls which I would like to get rid of. The problem is the pilot at the moment, just need more practise and more flight time would help that. I might increase the sensitivity of the cyclic as I'm having to move it much more than an R22 but not sure on that at the moment
One thought, maybe alter your seating position to either a more up position, or a more lay down position. An inevitable hard landing could easily shatter your spine... At the very least add as large a foam/styrofoam block between the seat and ground/skids.
Something to think about 👍
If you have a tilting mass it will be less responsive for larger helicopters. For your small heli it is manageable but when it comes to something with more carrying capacilty and something that needs to be more responsive then tilting the mass of something that may be more that a tonne in weight may be problematic. This may also be a problem on smaller helis as a heli isn't the most stable aircraft.
I can see the logic. I did expect mine to be much less responsive than an R22 for example and I was surprised by how responsive mine was. I still think the R22 is more sensitive on the cyclic, the cyclic control ratios are different between the two machines and I feel mine should be altered to make control inputs smaller. I personally think a larger rotor would react fast enough to be controlled as it's the aerodynamics that provides most of the power to tilt the disc not the pilot.
oh... interesting design.
i wonder if there are also intermeshnig rotor home made helicopters
Yep.
ua-cam.com/video/9TUbR5Zogv8/v-deo.htmlsi=qL2K0Qiow95U87Gr
Dick is an engineering genius
Seems like your hover height may have an effect on stability.
A blade diameter height above the ground in hover will help smooth or get rid of the huge amount of downwash turbulence generated by the rotors. You would still be well within a hover recovery height in case of a (ahem.. misshap 🙃) With lower dynamic gyroscopic stability from smaller inertial mass of the blades (vs Bell Jet Ranger for example).. your bird would be tossed about a fair bit more by buffeting and downwash being thrown outwards, then coming back via the prevailing wind direction, as well rolling ground turbulence from the wind anyway.
You must have some awesome experience in putting the machine together from scratch. Well done, and future best wishes.
Thanks for the input. Yes I agree going higher will be easier it's just having the nerve and confidence to do it. I previously made a decision to try 2-3ft after only going 6" and that helped a lot. I'm sure 5ft ect will be even better, in time it will get there and I'm looking forward to preferring that altitude.
The rotors are 14 ft diameter and the top rotor is 7ft off the ground that means to get out of downwash the skids have to be 7ft above the ground ?
@@Ben-Dixey If I may... I remember vividly .. day one when the instructor took me to a confined area.. (Bell 47 G2)
to get hover training. He showed me how he could hold the machine rock steady, using one finger on the top of the cyclic. My turn.. I had my arm on my leg, solidly,... a death grip on the cyclic..
My instructor had tears in his eyes watching my face, while I fight the time delay lag from my cyclic input, to re-action of the machine. I seriously thought of quitting..!! Thought I must have a defect in my motor control (lack of..) skills. But I could fly a full scale glider, had my private fixed wing license.. I was superman... surely I can fly.. what the H was wrong. ?
NO worries.. I eventually mastered the demon machine. 🤬
Then they put me in a turbine, (jet Ranger), with power assist hydraulic to all controls. Need I say "sensitive control"
Parked in front of hangar door, with all the class mates starring at me... and had to just pick the bird up.
Didn't think a human being could sweat so much from a simple hand control exercise..!!
You will get to the point where you can control the machine by holding the cyclic between your knees. trust me.
(and eating a sandwich).
Shall be following your endeavours... (wish I had a shop like yours ..!!)
Best wishes.
DO YOU HAVE A PILOTS LICENCE? NOT LIKING THE CONCEPT OF LEARNING TO FLY NEAR POWER LINES.
No I don't have a licence. The helicopter doesn't have the performance at the current blade pitch to go higher than around 3ft. You would also have to be flying above the hedge. No worries at the moment but when higher altitudes are achieved I will move further into the field away from the lines.