Fixed pitch Coaxial Helicopters are they any GOOD? Homemade rotary wing aircraft

Several attempts at a fixed pitch coaxial helicopter have been made and I talk about the pros and Cons of this rotor choice and also general thoughts to my project.
The redback aviation website
www.redbackavi...
Amazing diy projects
youtube.com/@a...
also check out helished for everything RC helicopters, very entertaining guy, you will enjoy
www.youtube.co...

[@HeliShed]

😂Ben - thanks for the video - outstanding research indeed! Regarding content: Brother, you carry on with the heart Pal - what is great about your channel is that you have the drive, intellect, resources and space, to give it all a bloody good go. And you do! For that, you are wholly deserved of support in whatever! Later pal.

[@Ben-Dixey]

Thanks so much Heli Shed, very nice comment. Really enjoyed your most recent video. You have a very natural presenting skill and are very funny. You should be proud of your channel size considering the niche but you deserve so much more.

[@licencetoswill]

keep us updated on both projects, as much as you can. Thery're both great exercises in engingeering by doing.

[@ryans5615]

I like both projects, and agree with this

[@miniphase]

Great to hear you're having heli ruminations again.... would love to see updates of both project please!

[@DktheWelder]

Cool stuff I honestly think you should post more stuff haha, your mate had some good input with not using the tape , what a genius

[@Ben-Dixey]

Yeah, waterproof tape is the way to go. 😉

[@amrinwello6620]

​@@Ben-DixeyI am very interested in the flying ship you made. Is a 40 hp engine powerful enough for an airplane, sir

[@Ben-Dixey]

Hi, yes 40 hp is enough for a single seat airplane. 👍 you can probably get into the air with 30hp or less if it's built light enough

[@amrinwello6620]

@@Ben-DixeyThank You. I'm sorry for always asking you. My admiration for you makes me consider you as my teacher

[@mattiasfagerlund]

Keep publishing flying boat videos, they're interesting too. There's yet another helicopter control method that was recently demonstrated by another youtube channel (Tom Stanton) where the rotor blades are hinged and free to move and the thrust of the motor is timed to control the attack of the rotor. As you could imagine, the thrust needs to be varied during different phases of a single rotation. This works for tiny rotors and very fast and powerful electrical motors. I'm not sure how well it worked and how well it would scale up though.

[@darkmann12]

It's worth noting it *just barely works* with the electrical motors, it stresses them out a lot and causes them to heat up very fast. I'm not sure how you would go about taking the idea and applying it to an ICE but if anything, I have more faith in it, as there won't be windings to burn out or demag+desync events, etc

[@Ben-Dixey]

I'll have a look, don't think I've seen the video you are talking about. Looking through Tom's videos it looks like there are quite a few I've not seen. Got some catching up to do ! 👍

[@lawrenceveinotte]

I'll watch and enjoy whatever you post.

[@kentuckyhelicycle2614]

Thanks Ben for the update. Either subject is fun and interesting. Hope you get the helicopter going for sure!

[@ultralighthelicopter]

Big thumbs up and thanks for sharing your progress...

[@Ben-Dixey]

👍 looking forward to seeing your Furia testing.

[@JPKrucker-ux4mc]

Keep posting all types of videos your a natural at it and there entertaining. You seam to be able to explain thing in witch it's easy to understand.

[@Ben-Dixey]

Thanks very much for this encouraging comment, it means a lot. I notice your username JPKrucker, he's one of the people I enjoy watching.

[@RubyS.1]

Pretty cool you picked one of the hardest things to garage build. Very inspiring

[@_XRMissie]

I've spent probably well over a thousand hours playing Besiege and designing helicopters, but coaxial swashes just break my brain. I can get as far as cyclic + collective, but I couldn't figure out how to set up the linkages to do differential collective for yaw, and I seem to struggle finding good technical drawings of these kinds of swashes. Whether you stick with fixed pitch or try out a dual swash system, you'll be back in the air in no time. If not with the heli, then with the flying boat! :D

[@ianmangham4570]

Forget about it

[@camillosteuss]

Glad to see you continuing the work! All the best!

[@K1VV1939]

Oh Hello! I've been waiting for you - in that time I've fixed all your problems so I'm really Keen on having your thoughts.

[@kiiiisu]

audio at end was so horrible that is was fun hahah and keep posting videos!

[@pyromaniac1441]

I actually didn't know you had a boat project because they never appeared in my recommendations. I'd be down to follow both projects.

[@pinocleen]

Same.

[@ptonpc]

Keep both. I thought you had gone quiet, I've have not been getting *any* notifications from your channel despite being subscribed and having the all notifications selected.

[@Aaron_b_c]

I'm very interested in both projects. Please continue both

[@suijin8187]

Like it! We build (FlyNow) an electric driven coax with fix pitch.

[@Ben-Dixey]

You do ? Is there any online information to your build ?

[@rockyrivermushrooms529]

We like seeing where any of your projects take you.

[@BricoleurTV]

Please, keep making videos regardless of them being about flying boats or helicopters

[@Ben-Dixey]

@@BricoleurTV Thanks for the encouragement. 👍 appreciate it.

[@ultratorrent]

Keep uploading whatever content you generate? I was drawn by the coaxial helicopter project, but I'm here for the person who built it now. The flying boat is cool in a similar way, but is unique and deserving of love.

[@Ben-Dixey]

Wow thanks, cheque's in the post! 😃

[@SteveWrightNZ]

Keep posting anything, its always nice to be in your workshop! :)

[@sky173]

Glad to see more content. Looking forward to seeing what you come up with next. Personally, I don't care what project you work on next. It'll be fun! Cheers.

[@shannonparker7404]

I love what you are doing! Please continue to share your adventures.

[@drawingboard82]

Just discoveredd your channel! What a brilliant guy you are! This might be the most British video ever!

[@dezent]

Both projects are interesting but helicopter project is truly what peaks my interest

[@abvmoose87]

Cool and good stuff! Stay safe

[@Ben-Dixey]

👍👌

[@shademe]

GLAD TO SEE YOU AGAIN

[@hublebubble]

Keep them all coming fixed wing and rotor craft😊

[@MrIanspeed]

Ben, as to your question about carrying on with the other project videos, well whatever floats your boat! 😂🤣 😀 But I'm really, really looking forward to the next iteration of the 'copter 🙂 but do what makes you happy. Good luck with both projects.

[@johnmackinnon1026]

Great video,Ben..

[@Ben-Dixey]

Thanks very much 👍

[@TheLincolnshireFlyer]

Love the heli stuff 😊

[@Ben-Dixey]

Helicopters are amazing machines, incredible what they do and how they do it.

[@shanakaliyanage6875]

Good to see you back in action. BTW, for some reason, I didn't get any notification after the helicopter rotor failure video. 😊

[@morkovija]

flying boat is actually pretty cool. Would love to build some sort of lifting body, super light GEV

[@ianmangham4570]

Awesome skills building that beauty 🤠🇬🇧🤟🙏

[@okgo8315]

Please please don't stop posting Ben 👍👍👍✌️🇬🇧

[@martingarrish4082]

I think the fixed wing flying boat project makes a lot of sense to sort out the basics of flight, but the occasional diversion into helicopter thoughts is also good to gently pull that project into shape in the background. Glad you have seen the light about collective pitch - I just wish the various e-VTOLs out there would also see that design for autorotation has many advantages. Regarding rudder movement then there are two reasons you really need it: The first is to correct adverse yaw from aileron deflection - in fairness not much of a problem for ~8m wingspan; The second is control the control yaw during landing or takeoff - so in ground/water effect you may find yourself relying on it a lot. In normal flight the rudder does a lot less, but allows coordinated turns (and pitch in very tight turns) or setting up a sideslip to dump height. So allowing +/-30 degrees is a good first assumption, but if you were nervous allow for +/-45 degrees then provision for an adjustable control stop so you can set it up after some flight experience.

[@Ben-Dixey]

Thanks very much Martin. I need to send you some updated figures. Appreciate the info on rudder deflection. Sounds like I might need to increase what I had planned.

[@martingarrish4082]

@@Ben-Dixey , to be honest if you've done some homework looking at other aircraft to produce a number for rudder deflection angle then stick with that. My numbers were estimates to be used as a starting point. I'll have a think to see whether I can produce some calculations for rudder and elevator deflections. I do get a bit nervous that I'm just swamping you with graphs that might not make that much sense. A video call might help me to explain the flight dynamics behind the calculations I am doing for you. At some point this will all be coded up into a more sophisticated tool for other home build aviation projects (hopefully some electric). Regarding channel numbers: build it and they will come. I didn't find the channel until near the end of your fixed pitch coaxial helo project.

[@Dougie234]

Yes please continue to present here what you can. It is a great creative channel / space. Your projects are inspiring and amazing. I'm sure I remember reading a commentary at the time on the Nolan brothers (I think they were farmers lol) who arrived at Oshkosk and proceeded to 'commit aviation' with their co-ax helicopter. Great to see a reference to them. Thanks.

[@Ben-Dixey]

Great 👍. Yes farmers I believe but i think one of them had a sheet metal business. What they achieved I'm still in awe of.

[@avivhod4968]

I’m slightly obsessed with flying boats like yours. Would love to see more videos about it!

[@Ben-Dixey]

Cool 👍 Have you seen James greenbergers channel? Also search Kester haynes.

[@aliasmari]

Thank you so much for your video

[@Ben-Dixey]

My pleasure 😊

[@rickshaw3005]

Awesome content. Please keep them all coming.i love seeing videos of home built aviation.

[@Ben-Dixey]

Thank you 😊

[@VacuousCat]

There's the Schofmann coaxial ultralight helicopter. It's a fixed pitch coaxial on a tripod. The pilot sits on one leg and pivots the rotors with the other two. It looks like if a coaxial is simplified and scaled down to that size, it's easier to build and control. (Franz Schöfmann from Stockerau, Austria)

[@Ben-Dixey]

The Schofmann was a big inspiration for my project and he did exceptionally well. Should have mentioned him. The hoppi copter is another I could have mentioned.

[@danko6582]

Don't build for views, build for yourself. Whatever that is, it'll help you maintain enthusiasm.

[@Ben-Dixey]

👌 thank you.

[@donaldpayne1376]

Thank goodness you're going collective pitch. I too have told the missus the sch2a coaxial would be a suitable Christmas present. Check out the Kavan it uses a control surface on each blade at about 2/3 blade span. Also for some reading fun search 300 pager Sikorsky document on different type rotor systems, roll up rotor, telescopic rotor plus many others. Yeah I'd watch your ground effect videos. Keep up the experimentation, to quote the legend Igor Sikorsky, ' some may think you're a crackpot until you hit the jackpot' :)

[@pinocleen]

Pretty complex route to take, I'd prefer a single rotor design, but having said that, there's so many resources for one to take, from traditional software to AI, which could help in his final design choices and related calculations. Same for fabrication, although he seems to have most of it covered.

[@Ben-Dixey]

The Kaman servo flap control is very interesting as is the intermeshing rotors. I don't think despite the size of the Kaman it has any hydraulic assistance. Controlling the blades in this way is obviously easier on control forces. I also believe they use wooden blades for the advantage of fatigue life. I like the design accept the big danger of approaching the helicopter from the side. The rotors get low enough to the ground to strike a person. I can't think of any other helicopter that uses servo flap control. Not sure why others haven't followed. This is dick degraw's syncropter he is an engineering genius. kzbin.info/www/bejne/b4W4k4Vrj9SarJosi=tQC7w6VmACR9E2Ye

[@donaldpayne1376]

Check out the Kaman seasprite a conventional single rotor with blade mounted control surfaces. I spoke with a crewman of an aussie military outfit asking what he thought and was it a smooth ride. Like you i thought it would unload the head from considerable aerodynamic stresses. 'When it was good it was smooth as, but the servos would play up and it would be rough as'. on asking about the servos job he couldn't elaborate beyond a power amplifier. Our airforce [nz] had them also and they turned into a money pit. Even so I liked the idea. The swash plate controlled what looked like a wire rope onto a pulley attached to a rod passing through the blade to the control surface. I would have thought it resulted in small undesirable changes in pitch while lead lagging and flapping.

[@Ben-Dixey]

Interesting stuff. Good to see a single rotor design with servo flaps in the seasprite. 👍 I haven't seen much in the way of pictures showing the mechanisms controlling the flap. One thing that you might think could cause an issue is the significant weight added to the trailing edge of the blade. It's hard enough to get a blade to balance at the 25% chord as it is. Your point about flap defection with blade movement is another.

[@donaldpayne1376]

Maybe do a search for "Wilson_A_thesis" He's done a paper on using a flap to control blade aoa on a chopper. Ì've no idea his past experience. I am yet to read it. Hopefully it saves several flawed iterations.

[@AlienLivesMatter]

New subscriber, avidly interested in the flying boat project. Great content

[@cloudusterable]

Probanly find Ben, De lackners flying platforms were fixed pitch but were flying in the ground effect all the time.

[@irisaviation852]

Love both but you will always get more interest on the helicopter.

[@lucashinch]

What about a ground effect craft? That would provide both "flight" and "float" forms of travel. Something like an inflatable airfoil perhaps attached to an airboat with a small powerplant. Homemade flight must be exhilarating. I appreciate all of your flying machines and most importantly the attention to design simplicity. Keep up the good work.

[@Ben-Dixey]

Hi, thanks for the comment. The flying boat I'm building is going to be a ground effect craft. I've heard about inflatable airfoil wings. An interesting idea. 👍

[@christopherleveck6835]

I'm more interested in fixed wing aircraft. In this case I'm primarily here for the flying boat. I would like to say that autorotation doesnt really happen from ground lift. The pitch of the rotor blade has to be brought down 👇 n a very smooth and controlled manner but it must be done quickly to maintain momentum as well. The idea is that coming down from altitude you are using the negative pitch of the rotor to turn them as the air goes through them and just before you touch down you are going to use that conserved momentum to allow for a change in the blade pitch to create enough lift to touch down at a controlled speed. If you loose a motor a couple of feet above the ground or in ground effect, the last thing you want to do is lose lift by dropping the collective. You won't have time or altitude to trade for a softer landing at that point.

[@Ben-Dixey]

Thanks for the comment, glad there is interest in the flying boat. Regarding autorotation at a few feet, there is something called a hovering auto where you use rotor inertia and collective pitch to cushion the landing. It shouldn't be called autorotation because it's not but from a foot or two above the ground it will allow the soft landing of the helicopter using the collective. At no point is the collective reduced in this instance, you only raise it at the correct moment.

[@z_actual]

generally aerodynamic surfaces used for control wont sweep more than 25 degrees GEVs usually keep their tails out of ground effect to be in a more normalised flow, and in doing so are usually T tails The easiest form of rotorcraft is the sutogyro, which can be coaxed into vertical lift if the rotor is driven. And perhaps like the Fairey Rotordyne using tip jets although almost certainly these days we could achieve the same with electrically driven tip props that collapse into a fairing when not in use. While single rotors are speed limiting due to retreating blade stall, this too can be supported by a small high speed wing on the retreating blade side. All landings could of course be under autorotation.

[@Ben-Dixey]

Great comment, thanks, very helpful. 👍

[@tomrobertson3236]

Choppers came out during korean war . They looked very primitave and just bolted together Ive always wondered why no one used modern tech to copy the early choppers Good luck

[@ramjet4025]

Fixed pitch is for hovering close to the ground only. It will be nice to see his results with variable pitch - Two engines mean double the risk of an engine failure. It means the fixed pitch rotor design is incapable of autoration and can never fly more than a few feet above the ground. The higher fixed pitch go the greater the guarantee of hospitalization or death. Its akin to hovering a piston aircraft at zero forward airspeed at a height greater than that which the skids can absorb a crash landing. Its a design that has dubious practical value. Variable pitch home built aircraft are the real alternative.

[@jnygaarddk]

Hi Ben, Greeting from Denmark. I'd like you hear your comments on a (maybe crazy) idea I been wondering about: Would it be possible to build a simple and somewhat cheap craft, that has a single fixed rotor and two tails split 90 degrees. Or what is the simplest/cheapest design you can make. Something big enough to carry about 200-250 lb worth of gun, ammo and sensor. Ignore the need for autorotate as it's for a drone. A normal quad/octo-copter setup is not feasible this size. Would need massive batteries and would still have too limited endurance. And adding an ICE with generator is too inefficient I think. Matters when we talk this much weight..... I guess you already guessed where it would be used. 🇺🇦 So send into harms way, that's why it need to be cheap. And preferably simple=resilient/robust. I was thinking an engine (maybe from an outboard) with the crankshaft directly on the rotor mast, if it would be able to be started without a clutch/belt. And with electric driven props for up/down control on the tails now there is no cyclic. Thinking about while I write, they might be better places low to the ground and push left/right and fwd/aft there. Not sure if yaw control on the tail should also be electric or it would be feasible to make a hollow tail NOTAR style and blow the cooling air out that way. Or the normal setup with a driveshaft and normal tail rotor is simpler/cheaper. Using the hot air would increase IR signature, but it might be huge anyways....

[@Ben-Dixey]

Hi, it's possible to make something like you describe fly. The rotor would probably need to be stabilised by Arthur Youngs stabiliser bar, which adds some complexity. If you had a main rotor providing lift but then a quad copter style outboard ducted fans or props for stability then I think you could have a fixed rotor without the stabiliser bar. Not sure what sort of speed would be achievable and therefore what the maximum wind speed would be flyable. There would need to be a gear reduction on the rotor as rotor tip speed needs to be around 600 ft/sec.

[@igorb4650]

Would watch flying boat video

[@pashimp]

I'm here for the design process rather than the design itself so boat or helicopter doesn't really make a difference to me. Please post the boat videos!

[@hinz1]

Fixed pitch chopper looks even more suicidal than those low mass bell rotor designs that have mast bumping and need a certain height/speed to do successful autorotation. No matter how many engines, if fuel is exhausted/interrupted for some reason, they go down, very hard.

[@Ben-Dixey]

Like all these things whether something is suicidal depends on the operator and the decisions they make.

[@FrankDyer]

Have you thought about an Advanced Rigid Rotor system?

[@Ben-Dixey]

Like the BO105 ?

[@ReavinBlue]

Have you looked into TIP-JETS? Especially COLD TIPJETS? think on it. Also, have you thought about a hybrid powerplant with an electric motor?

[@Ben-Dixey]

Well, I've thought about cold tip jets, the problem is efficiency. Looking at previous attempts such as the DJINN, it needs around twice the hp to lift that of a shaft driven machine of the same weight. I like the relative simplicity of the design but another difficulty is the transfer of air from an engine to the rotor tips without losses. I did hear of an electric back up system being developed for a helicopter in an emergency situation. Electric flight in helicopters is certainly being explored and it would solve a lot of drive train problems associated with IC engines. I'd like an electric version of mine but it's cost prohibitive for me at the moment.

[@ReavinBlue]

@@Ben-Dixey Where did u get that info on the djinn? I simply cannot find any reliable specific info on it no matter where I look. I've read that Horse power problem before aswell, but I attribute it to the very bad compressors of the time, today's are much more efficient! I guess the tubing is a challange and so is the rotor internal pipe and nozzle. But some dude made a tipjet helicopter with Peroxide, and if I'm not mistaken he was selling it, apperantly it reached up to 30 mins of flight with relatively small peroxide tank, so idk can it be that bad?

[@lohikarhu734]

Has anyone done an "electronic swash plate" system, that is electrically "steered" pitch over rotation, so that there are no multiple universal-joint connections, and mechanical coupling... just a multiple-redundant slip-ring system for power transfer, with the pitch control by torque actuators on the blades... The types of motors and actuators available today could be used with redundancy, and sensors for position, load and actuator position could provide all kinds of flexibility in control ideas... L also read about an idea that used a separate motor for each blade, which allowed actually changing blade speed/lift depending on rotation position, and I think used a kind of "differential" to change the blade pitch with instantaneous speed control, deceleration lowering pitch, and acceleration increasing pitch, kind of a hybrid of electrical and mechanical methods.... Anyway, just some idea floating around, and I guess that in "experimental" aircraft, you can have more flexibility in your personal design and build...

[@Ben-Dixey]

I don't know of a full scale helicopter that has used electronic servos to control a swash plate or rotor. I have no doubt it can be done and with redundancy. I considered the idea when contemplating a tandem rotor design. The mechanical complexity of controlling a tandem rotor would be very difficult to work out, but it would be much easier via a programmable rc transmitter. For a single rotor I'm not sure you will beat the reliability of a mechanical swash plate but with an electronically controlled swash plate a flight controller could be attempted. Not sure what price the servos would be.

[@erg0centric]

No food on the billiard table!

[@Ben-Dixey]

😆👍 very true.

[@magingi]

Could you have a single axiel rotor with a fly wheel beneath the seat attached to the same drive but rotating in the opposite direction of the top rotor, with relevant mass and distance to provide a counter to the top rotor to prevent the tail moving and provide gyroscopic stability?

[@Ben-Dixey]

Interesting thought. There is already a flywheel on the engine and that would be capable of applying a torque to the airframe but only under acceleration. It couldn't be used to counter rotor torque on a single rotor unless it was constantly accelerating. It would have to be big and heavy too I would imagine. The only way I think it's possible to use the stability of a gyroscope on a helicopter is to use Arthur youngs stabiliser bar. This provides gyro stability by controlling rotor blade cyclic pitch. The trouble is stability increases but at the cost of response time. There is more of a delay in control and this makes it harder to fly accurately. There is already a delayed response to cyclic control and the stabiliser bar makes it worse, but it's possible to get a helicopter to hover almost by itself using a stabiliser bar. Model Rc helicopters use them to great effect.

[@magingi]

@@Ben-Dixey Thanks for your reply. I used to fly RC heli's but am clearly out of my depth technically speaking. Or maybe, have the fly wheel on second motor. hehe. Any way...as you were. ;)

[@BrokenFarmer]

Did you heat the tubing to do the tight bends in the aluminum tail?

[@Ben-Dixey]

Hi, no I didn't anneal the tube.

[@PRH123]

Very interesting, thank you. Would this be a reasonable solution to the problem of autorotation: ballistic recovery parachute mounted on top of the mast. In other words accept autorotation is not possible with this design, and rely on the chute. BRS's are very reliable, mounting it on top of the mast would avoid intereference with the blades. Would that make any sense...? (Thinking about a solo sport aircraft only of course) Thanks..!

[@Ben-Dixey]

Hi, a ballistic parachute needs a minimum of 250ft and maybe that height with forward speed in addition to save you. An auto in a Robinson for example can be successful at 75ft with forward speed by comparison. So a BRS system can't replace the ability to autorotate unfortunately. They certainly can work attached to the mast though and I think I've seen that somewhere.

[@BillHimmel]

Are coaxials inherently more loud than conventional ones? After all, the tail rotor can be shielded, which reduces the noise significantly!

[@Ben-Dixey]

I don't know for sure but I think coaxial's would be slightly quieter than a conventional with standard tail rotor. The tail rotor is what causes a lot of noise. Ducted ones less so. Don't think any helicopter will be a quiet machine but us helicopters enthusiasts like the noise.

[@engineerahmed7248]

Put wheels to prevent rollover

[@Ben-Dixey]

That's a very good suggestion. 👍

[@roydengillies]

Hi Ben. I have complete sets of original plans for the AW95, the Skytwister and the original Adams Wilson choppy. Give me a shout if you'd like them for "reference material"

[@Ben-Dixey]

That's very kind of you. Will let you know if I decide to go in that direction. Thanks very much.

[@battleaxefabandmachine]

What about using electric motors, lightweight batteries and a lightweight 2 stroke running an alternator to charge while in flight? Electric motors have a better torque curve and you would have enough power to land if you have an engine failure.

[@Ben-Dixey]

Using electric as a power source would be nice, it's just very expensive compared to buying an engine. I could purchase a brand new Rotax 582 for less money than motors, battery's and a speed controller. As nice as electric power would be it's just too expensive at the moment. I think using an engine to provide charging power to the battery's would be false economy. The extra weight of the engine, fuel tank and generator would add a lot to the overall weight and you would see a reduction in flight time overall. Just my opinion on that and some calculations would have to be done.

[@battleaxefabandmachine]

@@Ben-Dixey I think you could stay under 15lbs with the right engine charging combo.

[@Ben-Dixey]

I guess it depends what increase in flight time you were hoping for. 15lbs is a very small engine powered generator. Using fossil fuels to generate power is best done directly through gears and shafts etc. Generating electricity from an engine feeding it to a battery which then turns a motor which turns a shaft is a lot of wasted energy. Wouldn't adding the 15lbs in extra battery's be a better option?

[@battleaxefabandmachine]

@Ben-Dixey I don't know, that's why I brought it up. I think electric motors have more controllable power and the torque is much better than any lightweight engine. Think about trains. There is a reason that it works.

[@Ben-Dixey]

Yes the smooth power and high torque is very desirable and worth finding out the answer because I don't know the answer, I'm only guessing. A friend of mine tried powering a helicopter with a hydraulic motor. The hydraulic flow and pressure was provided by an engine driven pump. The power transmission was beautifully smooth but so much energy was lost in the transfer it wasn't feasible. Also the extra weight of the pump, hydraulic motor fluid reservoir and oil cooling meant it was all too heavy. A train uses the torque of electric motors to great effect but at the cost of efficiency and weight. In an aircraft weight is king that's why I think the idea is a non starter. Happy to be proved wrong as I would love a motor to power my helicopter.

[@abinashdani5407]

Sir plz check your upper blade I think it's wobbling pardon me if I am wrong sir.

[@Ben-Dixey]

Hi, I've had this comment a few times before. I've not noticed any wobbling personally but thanks for the concern. The project is on hold for the time being.

[@abinashdani5407]

@@Ben-Dixey thnx for replying sir wish I could visit your innovation someday if my bhagwan wish

[@kennethschultz6465]

i was thinking of building a "" small"" chopper to take kids to schoool and they can take to school when big enough.. maybe 3 or 5 small seats.. the biggest of the kids can easely fly the chopper and pick up frinds on the way .. park at the school and walk the last way .. and put theather on the wings .. so other can park ther choppers cloase to our so it wont blow over

[@Ben-Dixey]

Well we all have crazy thoughts sometimes. I know I do. I think drones might do what you suggest one day.

[@walterrwrush]

Intermesh rotors maybe

[@Ben-Dixey]

Definite possibility, it's an interesting and efficient design. So are servo flaps for control

[@yxhankun]

why a counter rotating helicopter will fly when the upper blades n lower blades are spinning at the same speeds in different directions?

[@Ben-Dixey]

Hi, both rotors are producing lift even though one rotor is less effective. The lower rotor is able to produce lift despite being in the downwash of the top rotor. The point of a coaxial helicopter with rotors spinning in opposite directions is to balance the torque. No tail rotor is required

[@captarmour]

Did you say "Wing In Ground effect" vehicle?

[@Ben-Dixey]

Yes that's correct. I'm building a fixed wing flying boat operating in ground effect.

[@captarmour]

Fantastic, I've lived and breathed WIG for too many years now, I've built a few models, but not recently, and I've learned a lot through much research. I've noticed we humans tend to see what we WANT to see so I looked for videos with aircraft not designed as WIGs but stayed in ground effect so perfectly that they would react to the waves just a few feet under the wing! Are you interested?

[@Ben-Dixey]

@@captarmour Definitely interested in anything you are willing to share from your research. My first attempt at this won't be the best design for Wige but one that will work well enough. The main goal is to fly around at a few feet above the surface for fun. However I will have thoughts on improvements for next time and mistakes made.

[@captarmour]

I'm sorry I thought I replied...

[@captarmour]

@@Ben-Dixey kzbin.info/www/bejne/n2iUioSFbZaomZIsi=vWcjKw0RHunxAaIH Have a look at how this aircraft follows the ground so well that it reacts to the waves! Start vid at 2:15. It's simply amazing. This planform, Delta(swept wing)/Canard works IGE! The Bixel Planform also works, however due to the CG location a forward engine(s) placement may be necessary. The reason the Bixel works is because it simulates a swept or delta wing. The AC shift when transitioning between IGE and OGE is much less pronounced with a swept wing than with a straight wing. As we know when a straight wing is balanced for IGE flight, it wants to flip over backwards when it climbs out of Ground Effect. Although a large T tail may prevent it from flipping over, it becomes unstable to uncontrollable because as we know the Leading Wing must have a higher loading than the Following Wing. My 2 cents.

[@jonnyreverb]

Add a rotor to the flying boat and make a gyrocopter.

[@Ben-Dixey]

I could do that for sure 👍😀 the only problem is then I don't think it would qualify as a wing in ground effect boat. Would mean I'm breaking rules. You can pull it with another boat without any problem. It would be a gyro glider, kzbin.info/www/bejne/inSxi4Npi9merbMsi=LUy-x1-9zYXklx2b They were doing it a long time ago but you don't seem they anywhere now.

[@jebise1126]

is it paraglider flying boat?

[@Ben-Dixey]

Well similar, the boat part of this build is from a Polaris fib. A flex wing microlight.

[@jebise1126]

@@Ben-Dixey if it was paraglider flying boat you could cruise your boat than deploy parachute and fly away. it would be such a bond move to do.

[@shredderegypt3394]

the 2 rotor must have same RPM or not?

[@Ben-Dixey]

In my case yes the rotors have the same RPM but it's not necessary. You could have rotors spinning at different speeds. What matters is that the rotors are torque balanced, this is adjusted by the pitch of the rotors. With the rotors spinning at the same speed there is a 1 degree pitch differential between the top and bottom rotor in order to be torque balanced. You could choose to run the bottom rotor faster and have equal pitch between the rotors. I suspect that having them run the same speed is more efficient but I'm not sure if that's true or not.

[@shekhargaidhani1618]

@@Ben-Dixey in your coaxial helicopter, you kept 1 degree more in bottom rotor than top rotor?

[@Ben-Dixey]

@@shekhargaidhani1618 yes that's correct. 6.5 degrees on the bottom 5.5 degrees on the top.

[@shekhargaidhani1618]

@@Ben-Dixey 😍 Thank you Ben.

[@danirizary6926]

Flying boat!

[@ivaneberle3972]

Fixed-pitch helicopter designs are inherently poor at auto-rotation. That's an essential manned heli safety feature. (It's also why scaling up UAV quads to carry humans is a recipe for disaster.)

[@OYEUAV]

Please I need help

[@Ben-Dixey]

What do you need help with ?

[@Ben-Dixey]

Best to upload to KZbin but just have it as a private video. When you have done that you can allow just me to watch the video by using my email address. [e-mail]

[@OYEUAV]

Please I have sent you an email.. and the KZbin channel

[@Ben-Dixey]

Hi. Helicopter looks great 👍 well done for building it. What is it you need help with, what testing have you done ? I have tried emailing back but it says the email can't be delivered. However I can see your emails fine.

[@OYEUAV]

Thank you very much sir.. please I have sent you my personal details by email... Hoping to hear from you

[@BrilliantDesignOnline]

Sure, keep posting flying boat vids, every vid you produce is VERY educational; all the review of coax rotors and the associated engineering in this video is very good. Your vid production, narration and thought processes are greatly interesting. Collective, baby!

[@erniecamhan]

Still want to see flying boat videos 👍🏴󠁧󠁢󠁳󠁣󠁴󠁿

[@DumfriesDik]

I get the feeling Ben that Coaxial Helicopters are your home. I'd enjoy seeing any of your work BTW

[@RyanA14]

I'm interested in anything you build but particularly the WIG craft.

[@goobisoft4873]

pls update on helicopter project that's the reason i started followed ur channel and very interesting design u choose to build

[@sUASNews]

Keep going, I love your videos

[@tatami0131]

it look like very stayable, I'm cad designer, where can i find this paper drawing? hople can join this work

[@K1VV1939]

What you're looking for is the KA52 - about 2 years after Alaska goes back to Russia I'll be enabled to provide you the KA52 Tech - till then you're struggling with your mother so how do you crack the tech of the KA52 at Home without get shut down.

[@rajeevshagun7409]

Brother Ben , you have collected Great information on coaxial helicopter. Thank a lot for sharing it with us . And I noticed that your coaxial project gave you lot experience how to handling coaxial without collective pitch. Flying boat project can be another interesting project. Cool cool . Regards

[@TouYubeTom]

boats too, please.

[@johnosmers4374]

Hi Ben, I built a prototype coaxial helicopter some years ago. It was never untethered from its test stand but alot of valuable data was collected. I didn’t like the complexity and reversal problem in auto rotation of variable pitch on main rotors. I chose to fit a simple tail rotor as there is no torque to compensate and can therefore be relatively low thust and still maintain a short tail and would maintain smooth yaw control in transition from powered lift to auto rotate.You could even do it more simply by embedding 4x little electric,reversible model plane motors into you tail section for full redundancy and shield them from rotor down wash and sound wave collision which can have a major acoustic penalty. In the event of all electric motors failure you can auto rotate with foward speed with rudder control till touch down.

[@Ben-Dixey]

Great stuff, thanks for the comment. Well done for working out the very complicated control of twin rotors via swashplates and differential collective. Your idea to use electric motors and props would be a good one. Definitely worth exploring on a coaxial, I don't think I've seen that attempted. Have you seen this video where Oskar has developed an electric mosquito air? kzbin.info/www/bejne/e5Wyo6SnjL-pgrssi=fxRUNcPuLPxgF34x It has the same electric prop configuration as you suggest but it's having to counteract a single main rotors torque. As you say on a coaxial you wouldn't need much. Tail vanes as I chose worked ok but I think during one wind gust it became ineffective. You could have good yaw authority with the electric setup. I hadn't considered this option until you messaged. Are there any details of your build online ?

[@johnosmers4374]

No details of our build were published on line, sorry. The person that was financing the project got sick and died part way through. His daughter sold up all of her father's stuff and I purchased the coaxial project but have not had the time to continue it. I know Oscar and was a student of his when training for my gyrocopter license and have seen his prototype electric mosquito video's. I got a lot of inspiration from the Russian Rotor fly project. But that to came to a stand still after a problem developed between them and there German partners. I think Germans went on to develop there own coaxial helicopter and have completed a commercially available unit. I can't recall the name of it but the main researcher was publicly funded and all of his study documents are or were avaliable on line to study,if you want to do a deep dive into the subject but very interesting reading for people like us.

[@mitubachiflight]

I've been watching your swashplateless helicopter since the beginning and was excited when it first left the ground. Successfully designing your own helicopter requires a lot of knowledge and skill. Amazing that it flew as designed! I don't know which direction you'll go in, but I'm sure it will be interesting.😀

[@gafrers]

Wonderfully explained

[@checkmate058]

I like flying boats. What of a twin rotor Flettner Fl 282 type design?

[@Ben-Dixey]

I do like the syncropter designs, they are interesting and would suit a small homebuilt. Dick Degraw built one kzbin.info/www/bejne/b4W4k4Vrj9SarJosi=5SdXIxCoLjTZ1gwl

[@lysanderkrieg5474]

I suggest you look to Anton Flettner for a reliable intermeshing rotor system.

[@Ben-Dixey]

Yes, a great design. Big fan of Kaman helicopters too.

[@ronchappel4812]

I havent thought much about homebuilt aircraft for decades so i find this super interesting. What's with the loose fabric wings at 8:30?Are those meant to be self shaping when run at the correct angle?

[@Ben-Dixey]

Hi, the fabric was just to give a visual idea of what it's going to look like but the wings definitely will be fabric covered. I could choose a single skin wing like the hoverwing and mudskipper or I could choose a double skin full airfoil like microlights have. Someone in the comments reminded me of Rudy Heeman's flying hovercraft and he used double skin wings with two aluminium spars and foam inserts to keep the shape. Single skin wings do inflate to form an airfoil of sorts but it's not exactly the most efficient of wings.

[@ronchappel4812]

@@Ben-Dixey Thanks for the detailed reply.All very interesting.

[@monostripezebras]

that was pretty awesome.. good luck and happy landings with your future flying!

[@omnianti0]

WHAT ARE THE DRAWBACK OF SYNCHRONOUS DESIGNS? LIKE K-MAX?

[@Ben-Dixey]

The Kmax drawbacks are: The blades come close enough to the ground to be a danger to people approaching the aircraft from the side which I think could be the reason for its lack of use as a passenger aircraft . Kmax use servo flaps to control the rotor and that means wooden blades are used for fatigue resistance, wooden blades are expensive. Synchronous designs have some unique handling characteristics. That's about as much as I know about the drawbacks of the K-max design.

[@omnianti0]

@@Ben-Dixey BUT IF WE TALKING ABOUT DRONE THEN WHY THE SYNCHRONOUS COPTER NOT REPRESENTED? YOU POINTED AS FLAP PER DESIGN BUT WHY NOT TRADITIONAL COLECTIVE/CYCLIC ?

[@Ben-Dixey]

The video was mainly about the downsides to fixed pitch rotors. Synchronous Helicopters are very interesting though and should be talked about in another video. A standard swash plate design can be used on synchronous helicopters, servo flaps were another way of doing it.

[@omnianti0]

@@Ben-Dixey ah ok thx im actually atempting to decid what design i must follow and im not convinced with coaxial due to complexity and asymetry

[@Ben-Dixey]

@@omnianti0 What are your goals ? You can buy helicopter plans like the AW95, that would be the easiest route or certainly take some ideas from the plans.

[@56Seeker]

All the videos are good

[@Ben-Dixey]

Appreciate that. Thanks 😊

[@migalito1955]

Either heli or flying boat is fabulous for being the fly on the wall via watching your videos. I only build and fly RC due to shop size and budget considerations, but even when I was five years old I wanted to build the real thing as indicated by asking grandpa to help me build a small plane for flying in. I must admit helicopters then and now seemed & seem awfully gosh darn complicated.

[@Ben-Dixey]

Thanks for the comment, Helicopters are very complicated and hard to get your head around all that's going on. They are fascinating machines.

[@IanSpeakes]

Dont give up on the chopper you can do it i loved the videos your clever man you can make it work 😊

[@darioinfini]

I knew you'd be back at it. Good for you. Look forward to seeing what you come up with.

[@Ben-Dixey]

Thanks for the encouragement, definitely more to come. 👍