Contra-Rotating Coaxial Propeller Drive

Video render of a contra-rotating, coaxial drive for an airplane propeller. Modeled in Fusion 360 and animated with the Blender 3.0 Eevee render engine.
update 12/17/22
There's been some discussion in the comments about the need for contra rotating propellers and why these aren't seen much in modern use. I believe the answer is that these designs were seen at the apex of piston/propeller technology in the 1940s and 1950s when manufacturers were doing everything they could to increase the performance of airplanes within the limits of the current-day tech.
An advantage of contra rotation is that it eliminates torque, p-factor and gyroscopic precession effects on aircraft handling qualities. They also allow use of smaller diameter propellers than comparable single-prop aircraft.
Jet engines also have these advantages and produce more thrust at a lower engine weight.
There have been some comments about why I chose to animate this design instead of a planetary gear configuration. There are multiple ways to achieve contra (or counter) and this is just one of them. There's a NASA technical memorandum (NASA TM 82983) that compares different configurations. The one I animated here is a dual compound idler and is less efficient when compared to a differential planetary gearbox. It is also cheaper and easier to manufacture
Here's an animation of a planetary contra rotating gear box: • Contra rotating propel...
There were comments that it's not possible to achieve 1:1 rotation of the inner and outer shafts with different size gears. This isn't correct. Different size gears are needed or else the drive wheel will clash with the idler gear. The ratio of pinion teeth to wheel teeth is the same for each gear set (even though the sizes are different). It's this identical ratio that allows 1:1 rotation.
This is loosely based on the Rolls Royce Griffon gearbox. Check out this video posted by FlightEngineering1 at • An Explanation Of The ... to see a view of an actual Griffon gearbox.

[@noesantana_com]

Seriously, thank you. This has been one of biggest question I've always wanted to know but didn't know who to ask. Your animation skills are on a mad level. Thank you for taking the time.

[@CFox.7]

there are some legends on the internet

[@sefutho]

Me three 😂

[@syedatif8159]

I have been working on electric coaxial propulsion system. Seriously this is awesome and very helpful. Thanks.

[@bzig4929]

Glad it was helpful!

[@syedatif8159]

@@bzig4929 Stay blessed.

[@RedRyan]

@@bzig4929 you actually rock. Totally solid

[@bzig4929]

@@RedRyan wow... what a nice thing to say! thank you.

[@honkhonk8009]

What u gonna use them for? Drones?

[@JohnJohansen2]

Great! With animation like this, suddenly it all appears very intuitive.😀👍

[@cergeyivanov7566]

Now u know how tu-95 manages to break eardrums of everyone close to it

[@mattmilford8106]

I was about to say, I bet it makes a heck of a racket. It looks similar to how sirens are made.

[@user_lipezdronik_63]

На Ту-95 стоят двигатели НК-12. Там редуктор абсолютно по другому устроен.

[@ThatMontmorency]

No, it doesn't. The loudest propeller plane was american XF-84H, which did feature contra-rotating propellers and was very inefficiently designed. It's noisiness is the indicator of its inefficiency. And it had only one pair of propellers. Meanwhile, Tu-95 has four pairs, and yet it is one of the most efficient propeller-driven airplanes ever built. It is very quiet by propeller-driven aviation standards.

[@PrintScreen.]

sure thing bruh kzbin.info/www/bejne/qGq2ZJtpbKyKaMk

[@Tim-Kaa]

@@user_lipezdronik_63 там редуктор планетарный

[@HesFoset]

I really needed to learn this. I have always wondered how the world's fastest propeller planes work, or more precisely, how their gearboxes are.

[@bzig4929]

It's interesting to see where these came into existence in the history of aviation... right before the jet age. I believe this is why you don't see many of them in service today. The fastest prop plane is still slower than most jets.

[@claiborneeastjr4129]

The gearing is fairly straightforward and simple once it is showcased like this. This animation takes the mystery out of the system.

[@user_lipezdronik_63]

Осталось посмотреть, как в двигателе НК-12 для Ту-95 сделан редуктор, передающий 15000 лошадиных сил. И понять, что данное видео - не более чем игрушка

[@alooga555]

Now it all makes sense. Thank you for visualizing the mechanism.

[@JG300Stoopy]

Might be the coolest video on KZbin ever... wish it just went on. Thank you!

[@bzig4929]

Thanks! That was a super nice compliment.

[@richardteale8203]

@@bzig4929 You're welcome, as I agree with them. The best bit was when it split, as I got it well with the first part, yet many if not most would really appreciate the split bit to highlight how it works! Cheers.🍻 Rich.😎

[@waynep343]

Have an odd number of propellers on the second so the shockwaves from the first don't line up with every blade on the second. The leading edge of the second propeller needs to have a sharper design to cut thru the compression wave from the first. There are electric motor designs that have a hollow core armature shaft. So you can get creative with inner shafts spinning the other way.

[@crackedemerald4930]

It helps against them resonating like crazy too I'd imagine.

[@heftosprod]

Have a look at the Russian NK12 system.... Uses a differential drive where the inherent lag on the rear prop makes sure they can't synchronise. And what a noise.

[@NeriEngineering-oq6vh]

Beautiful design, beautiful computer animation!

[@bzig4929]

Thanks! Very nice of you to say.

[@ronjon7942]

Nice work. When looking at the Tu-95, the forces that the gear housing contains must be enormous. The transmission seems as though it exists to tear itself apart! Doesn’t take too much imagination to understand why there were so many problems with WWII and postwar prototypes that used contra props.

[@LitoGeorge]

Extremely good!

[@tulsatrash]

Thank you!

[@flixpods]

Superb design. Generous for sharing it

[@lesliesemrau9826]

Excellent rendering!!!

[@graham2631]

Nicely done, thank you.

[@РостиславКолесов-к5о]

Да, только в этой схеме должен быть разный шаг винтов, у заднего винта - больше. Иначе кпд будет низким, а прирост тяги от второго винта - маленьким.

[@АндрейПросто-т5х]

Тоже об этом подумал, считал обороты винтов на видео)

[@ОлегКо-э9к]

а где на видео указано что шаг одинаковый ?

[@ОлегКо-э9к]

а что вам даст это занятие ?@@АндрейПросто-т5х

[@danwilkes3818]

Holy sh*t that was sexy. I mean woo, damn. The mechanicals had me, but the music was over the top! Five stars gentlemen*****

[@Nickson-mwm]

Beautifullll 😮

[@adrianobh9247]

Amazing! 😊

[@edwardleyden460]

At last . Now I know many thanks for that .

[@Workerbee-zy5nx]

Ahhhh, so that is how that works.

[@roystonmascarenhas7947]

good work, you have solved my doubt

[@n7346e]

It’s a lay shaft, just like a reverse gear on a manual transmission. I never woulda guessed.

[@lanceroark6386]

Why is it so complicated? Engineer: so no one can trademark a similar design.

[@chrismitchell45]

Killer music!

[@marlinmixon3004]

As electric power starts to replace internal combustion engines, it will be possible to eliminate this complexity and locate two small but powerful electric motors on a stationary shaft directly connected to two separate propellers. If one motor fails, only the one propeller will stop and the other will continue to operate.

[@gsxr1kmatt]

I’d love to 3D print something like this.

[@msec2000]

The axial Roller bearing should be holding against the oposite direction. Cheers.

[@СергейДикарев-л8щ]

Фантастика!

[@bzig4929]

Thanks!

[@daruween1398]

That's is surprisingly simple

[@deepsleep7822]

I don’t understand how this can produce that much more thrust to warrant the potential mechanical headaches this thing can cause. IMO, a lot of moving parts.

[@isakjohansson7134]

Its not that complicated, the second propeller stops the wirling from the first and increases the thrust since the air will go straight back. For the second propeller the effect is essentially that of spinning faster without actually doing so.

[@craigrmeyer]

I’d appreciate a longer and slower version of this.

[@SergeantPsycho]

This puts me in my happy place. xD

[@manuelviniegravargas142]

Awsome. Thanks

[@shermatovkhurbek3311]

Түшүнүктүү.👍👍👍

[@MrEntropus]

Гумбардунлы цоб зул!

[@ardi5849]

@@MrEntropus малое баузрп она мджзу

[@seanmcgee8184]

Great Job

[@bernardopercyvant5206]

É só isso mesmo kkkk, pensei ser mais difícil!!!!

[@basiltaylor8910]

Very Massey Ferguson, the gearsets out of said tractor, Luke Hobbs engineers at Pratt&Whittney designed a very compact epicyclic gearbox for a double drive contraprop R-4360 that flew in a Boeing XF8B Carrier Attack Bomber.

[@bzig4929]

Thanks so much for that history! I loosely based this on the RR Griffin and the contra gearbox used on the Avro Shackleton.

[@basiltaylor8910]

You are most welcome , yes the double drive contra prop gearbox is from a Mk 58 Griffon. But as I said before, Luke Hobbs of Pratt&Whittney created an epicyclic gearbox for the same job which is far more compact , lighter and cats&kitten a version of this gearbox is in active use on the NK14 turboprop designed in the mid ,50,s by Nikolai Kuznetsov, guess which Russian Cold War Bomber is powered by NK 14,s.

[@alexeyguryev4568]

Is it necessary for both propellers to have the same rotation speed?

[@-sturmfalke-]

Probably, because a slower moving propeller in the front would hinder the flow of air through the second propeller, whilst a slower moving propeller on the back would work like a brake to the airflow being pushed towards it by the front propeller. Its like having a solid wall directly in front or back of a propeller, no airflow would occur and thus no forward pulling force. It would also be a lot of physical stress for the propeller. Also, in the design shown in the video, they can't rotate at different speeds, since the gears are linked.

[@mostaphanaghibi480]

Thanks. Grate job. I have a question : please tell me about bearings with inner and outer rings rotate in opposite directions. I mean fits and tolerance. They are hole base or shaft base?

[@endoucheeray7018]

What really interests me is that Instead of having a gearbox made up by 3 extra gears, why don’t the engineers give a try of a single bevel gear, just like the differential setting for the cars?? Isn’t that much lighter and easier to maintain?

[@brianb-p6586]

That is an alternative design, but it isn't any simpler than the parallel gear design shown here. Also, bevel gears require precise axial position control for proper mesh (which is why setting up the pinion gear in a common automotive final drive is an involved procedure); parallel gears do not require that.

[@KiKi-pn7is]

👍👍👍👍👍👍👍

[@barriewright2857]

Thank you know I understand how this design of aircraft propulsion systems works. I have seen this design on aircraft before and have always wondered how does it work and know I now. Is this the same design used in helicopters like the Russian Ka-50 or the up an coming American sikorsky s-9, but modified for this type of aircraft, Brilliant design .

[@renaissanceman5847]

you should have just used two bevel gears (one fore each prop) facing each other coupled together by one or two smaller bevel gears between them... it would be more efficient.

[@bzig4929]

Yup, or a planetary. I have another video where I did those options also. This one was used on the rolls Royce griffon.

[@brianb-p6586]

That would provide the reversal, but this configuration also provides a speed reduction.

[@oliverscott7424]

So that's how they work.

[@ronparrish6666]

Can you do one on the engines on the old Electra i think it had something from GM that actually shifted gears in it

[@bzig4929]

I just did some research... I read that they had different prop governing ranges for taxi and flight, but so far I think it was a single reduction gearbox. I'll read more... Sounds like a cool design.

[@Tim-Kaa]

Great work for visuals and concept presentation. This type of gearbox was actually used during WW2 in England engines cuz they were cheap and had survivability of a few combat hours. In modern engines in helicopters and airplanes the gearbox for this purpose is based on planetary reduction. Also, trust bearing is in the wrong direction, unless it's a pusher type prop. Do you do commission work?

[@Tim-Kaa]

kzbin.info/www/bejne/bpK6iZVjaK2losU

[@bzig4929]

Thanks for the comments! There were some responses to this video that the only way to achieve contra-rotation is with a planetary set... I should have said in the original description that the inspiration for this was the Rolls Griffon engine and that this was an actual configuration that's been flown. I edited the description to show this and included a link to a video of the Griffon gearbox. I also linked to a NASA TM that presents the advantages and disadvantages of the various contra configurations; As you said, this one scores high on acquisition cost and technical risk... although not so high on efficiency. I'm doing this as a hobby... not commission; but if there's something you'd like to see, put that in the comments.

[@CoolStyleSir]

GOOD vdo like it

[@donk2metal]

Kommt gerade gut.Morgen muss ich 10 Planetengetriebe zusammenbauen. :-)

[@himmetramthakur6525]

🌹🌹🌹

[@glike2]

I'm surprised there hasn't been a drone made with this kind of tech as it could be much more efficient than multiple small rotors. Maybe the complication is not worth it too expensive.

[@Fiberglass_Insulation]

Which type of drone are you exactly talking about?

[@aerry654]

What would we do without roller bearings

[@Avernaught]

Narval lore

[@BlueJazzBoyNZ]

I would have liked to have seen one of these fitted to the STOL aircraft DRACO (RIP)

[@miro_s]

Is there an advantage of this design? Would the second propeller have any air to propel?

[@FondlesHandles]

there would be less air for the second prop to move, but not as much as you would think, and the benefit is counter acting engine torque. in any single engine prop planes, propeller rotation affects roll rate of the aircraft, boosting it along the axis of rotation, and impeding it when rotating against the propeller. vehicles like the westland wyvern and the a2d1 skyshark solved this problem by making contrarotating aircraft. by all reports, they were a joy to fly, being extremely stable aircraft. the downsides of these types of aircraft were the fact that they were extremely loud, a high pitched noise that was a combination of the gears spinning and the turbochargers, and those gears tended to wear down quite quickly.

[@ДмитрийБочкарёв-и2т]

why not use the gear wheel wisely and place it between the gears of the drive shafts, this will reduce the weight of not only the torque transmission, but also the casing of the apparatus and its manufacturing cost

[@mukbus5935]

coaxial

[@轉龍呼吸法-y4p]

Additional gear wheal make it possible.

[@Orinslayer]

When Mississippi Queen edit?

[@SA-so7jah]

Просто 🎺

[@danielhandika8767]

Why don't just use planetary gears?

[@bzig4929]

A planetary would give a gear reduction, but I don't see that a planetary alone could provide opposite direction rotation. My intent on publishing this was just to show a visual demonstration of one means of achieving this. There are other ways. Thanks for commenting!

[@danielhandika8767]

@@bzig4929 the sun gear and the annulus gear will spin at different direction if the planet gears are stationary

[@VJETRA]

@@danielhandika8767 then its no longer a contrablade is it?

[@ДимаКулаков-с2ю]

Я вот двух вещей не могу понять, почему несущий конусный подшипник установлен так будто это толкающие винты а не тянущие, и если они тянущие, как они крепятся к валам, по такой схеме как тут, они бы слетели со шлицов и улетели бы перед самолётом

[@bzig4929]

I don't show a gearbox, but I envisioned a thrust deck in the gearbox where the front of the taper bearing would react loads from the prop shafts.

[@mrmped1]

Wouldn't a planetary gear set work?

[@harlander-harpy]

I always figured they used a planetary stage to reverse the rotation but I guess this is slightly more efficient

[@bzig4929]

There's been a lot of comments here that the planetary option is better... No one has really said why. This config constraints the rotation speeds as mechanically equal. The planetary would allow different rotation speeds. Contra props aren't that wildly used, but both of these configurations have been flown.

[@backho12]

Certainly, longevity would be better with a planetary drive

[@harlander-harpy]

@@backho12 i disagree, for one planetary drives have more moving parts, more gear meshes meaning more temperate and resistance

[@backho12]

@@harlander-harpy Less load per gear tooth. That’s why they’re so widely used in heavy duty axles.

[@endoucheeray7018]

Would a single bevel gear be even more efficient?

[@mrrolandlawrence]

Fixed pitch props?

[@stevespitler3070]

Where's the thrust bearing?

[@bzig4929]

my thought was the tapered roller bearing on the front would mate to a thrust deck inside of a gearbox (a gearbox that isn't shown). Someone told me I CAD'ed it backwards, but I don't understand that... as the rollers would fit into the bearing cone that reacts thrust against the front of the gearbox. Do you have an opinion? I'm an engineer, but I don't know bearings from squat... I'm doing this for fun.

[@vp7211]

Музыка супер

[@solarflare623]

Is that what it’s really like? I feel like just using a bevel gear would be much less complicated and maintenance intensive.

[@bzig4929]

The rolls Royce griffon does it this way. Some others use planetaries. The bevel gear would work also. I suppose all design choices are trades. Thanks for watching and commenting!

[@holgernarrog962]

Is the efficiency of a contra-rotating 2 - prop system higher than that of a single prop system? Why?

[@bzig4929]

Yes, there is a gain in efficiency. Check out NASA report "Technology and Benefits of Aircraft Counter Rotation Propellers" TM 82983. Reduction of splistream swirl is one of the reasons for the increase in efficiency. However, the slight increase in efficiency is not enough to justify the cost and complexity of the design.

[@ash.ab.5575]

apart from counter torque what is the advantage for propelling the aircraft?

[@Tim-Kaa]

15% more trust and no counter yaw.

[@mamoru0728]

プロペラのピッチコントロールはどうやってるの？

[@alekkce-7776]

А разве коническии подшипник правильно установлен?? По-моему он должен повернут другой стороной.но может я и не прав если тага производится за внутренюю часть то тогда все верно

[@bzig4929]

the translated question is whether the tapered roller bearing is installed backwards. I don't know... not shown in the render is a thrust deck that would be within the gearbox to react thrust loads. So, the propeller shaft would apply a thrust load to the inner bearing ring, and this would be reacted, by the thrust deck in the gearbox, at the outer bearing ring. Is this correct? I wonder if a double-row bearing set might be more appropriate... thrust would predominantly be in one direction, but they could reverse during rapid deceleration.

[@jarenbigelow8606]

What is this industrial p©® #?

[@dranrebalgones1610]

What is the specific purpose of this contra rotating prop?

[@bzig4929]

there have been lots of comments asking that.. I added some details to the description.

[@jtuttle11]

I really Don't think this particular setup would work. You would absolutely need to have the exact same gear ratio for the inputs to the propellers and the gear reductions are clearly NOT the same. This would cause one prop to spin faster than the other and the torque would also be unequal.

[@bzig4929]

The gear ratios are the same; the CW gear wheel is 32 teeth with a 12 tooth pinion. The CCW setup is a 40 tooth wheel and a 15 tooth pinion. 32/12 = 40/15. The size difference is necessary to get clearance for the idle gear, otherwise this would need 3 idle gears to separate one shaft from the other and still allow gear mesh.

[@unguidedone]

this is something i just cant walk up to someone and say "CONTRA-ROTATING" "CONTRA-ROTATING" ???? how does it work or i would get strange looks. you should do a video and show magnetic field lines in a linear motor or the fluid dynamics of thrust going out of a rocket nozzle

[@GuilhermedaSilvaCaetano0095]

this projecr i will call ripslinger (disney planes) propeller

[@amirfmaster2515]

What CAD software do you use?

[@bzig4929]

Fusion 360 for the CAD. I rendered this in blender.

[@BLKSG6]

Why wouldn’t this be designed like a car differential with two bevel gears facing each other and a single gear between them? Wouldn’t need that reverse gear. When you put a car on a lift and spin one wheel, the other wheel spins in reverse at the same speed

[@bzig4929]

That would also work, as would a planetary.

[@DersNoNem]

The other set of gears have smaller size yet spinning at the same rate

[@bzig4929]

good observation! this was intended and is done by setting the ratio of each wheel/pinion set to the same value. In this case, it's the CW gear wheel is 32 teeth with a 12 tooth pinion. The CCW setup is a 40 tooth wheel and a 15 tooth pinion. 32/12 = 40/15 so each shaft has the same rotational speed.

[@DersNoNem]

@@bzig4929 was this setup used in real life? Because of the space conditions?

[@bzig4929]

The rolls Royce Griffen engine had some applications with a contra rotating gear box. That was the inspiration for this render.

[@igorrpetrov4236]

The famous Russian NK-12 turboprop engine has a fundamentally different system to separate the rotation.

[@PeterM4321]

German design by engineer Bockermann.

[@igorrpetrov4236]

@@PeterM4321 Really? we do not write anything about it.

[@ОлегКо-э9к]

феймос русский нк спроектировали ученые и талантливые немцы -))))

[@erwinarief4567]

like in Russian Bomber TU 95

[@ThatMontmorency]

No, not even remotely similar. The design shown in this video is not viable.

[@bzig4929]

This was intended as a simplified view of the gearbox used a the RR Griffon engine for several aircraft. I believe these never became popular, not because of any defect, but only because jet engines, coming on the scene about the same time, produced more thrust per mass of the powerplant.

[@girohuang5196]

P63 king cobra 😊😊😊

[@hashteraksgage3281]

It didn't have this propeller. Look up the J7W.

[@segaseda]

С какой же скорастью крутится турбина там минимум передача 3.1.

[@СергейЯсинский-у9м]

Косозубые шестерни в авиации не применяются, только прямозубые.

[@ОлегКо-э9к]

в какой авиации не применяются ?

[@akbarshoed]

Sue-eeeet

[@СергейАлексеевич-и3щ]

Лично я не спорю что встречно вращающиемя лопасти винта поидают большую скорость отюоасываемому потоку. Допустим что на 0,7 радиуса линейная скорость винта 250 м/сек, один придает потоку скорость 250 м/сек второй парирует уже со скоростью 500 м/сек, но и мощность нужна соответствующая Я бы после первого винта поставил пасивное устройство для ускорения потока, и получил бы уселичение примерно в 1,4 раза, при затратах энргии в два раха меньше.

[@ОлегКо-э9к]

ставь, мамкин конструктор .

[@СергейАлексеевич-и3щ]

Отвечу взаимностью; не твоё собачье дело что я поставлю и туда я поставлю

[@ОлегКо-э9к]

ваш ассоциативный ряд настораживает , вместе с техническими решениями поца без опыта и образования . Придурок , как ты в центровку попадешь и в низкие коэффициенты матрицы управляющих моментов ? Внешний контур туда еще налепи сверху .@@СергейАлексеевич-и3щ

[@СергейАлексеевич-и3щ]

Всё собрал в кучу и матрицу и центровку и упрпвляющий момент. А что центровать то? А что за матрица? А управление чем или кем?

[@ОлегКо-э9к]

шлема , вы не интересны , ставьте свой статор на трактор и будьте счастливы .@@СергейАлексеевич-и3щ

[@Player_2725]

My brain when I need to do a task that will affect my whole life:

[@JESUSCHRYSLER5512]

TURN THE DOIBLERSCHZORBLETSARGLER AND YOU WILL GET DARZHNARZHDICATED.

[@ericdillan8961]

do you have the 3d model

[@bzig4929]

yes, I modeled this in Auto desk Fusion

[@toadamine]

That'll last about a week in real use at full rpm for hours on end... lol

[@korastez9560]

Now I can die. Thanks.

[@zy8719]

What are the advantages of a coaxial design?

[@maciejnikiel6492]

Removes the torque from the blades spinning in one direction giving the plane constant "push" to the roll direction

[@zy8719]

@@maciejnikiel6492 That makes sense, but does it provide any aerodynamic benefit? Also, then why would it be used on multi-engined aircraft?

[@maciejnikiel6492]

@@zy8719 If you have really powerful engine and try to put all of its force into one propeller its tips are going to breach the sound barrier damaging the blades AND making so much noise it can be a health risk. By spreading the force on 2 propellers you mitigate both risks

[@vascoribeiro69]

On Seafires it allowed reduction of prop diameter (from a 5 blade unit) for carrier landings, neutralized the torque (on take off you might apply full power without rolling), the factor P ( the blade on one side has a bigger angle of attack than the opposite considering a given wing angle of attack) and adverse yaw (the helicoidal slipstream pushes the rudder to one side). On Shackleton it reduced also the prop diameter, which allowed the engines to be closer to centre line and the undercarriage shorter, lighter and stronger.

[@zy8719]

@@vascoribeiro69 Thanks!

[@vanpenguin22]

And ziss ist hau ze Tupilev bomba cutz srou ze aire a zo it wer buttah.

[@ДмитрийКорбут-ъ5с]

Враньё, обороты не синхронны, винты должны вращаться на одной скорости.

[@MrWireguy]

Why do this? What is the fluid dynamics behind such a config?

[@bzig4929]

This configuration has a slight increase in propeller efficiency... But probably not enough to justify the increase in mechanical complexity or the weight of the gearbox. This design eliminates the rolling tendency caused by torque. This is old tech that came on the scene with high-power piston engines just before the jet age.

[@MrWireguy]

@@bzig4929 Thanks.....recently saw this on a power boat and was wondering ...."Why do this?". I could see that it would be pretty useful on aircraft where small amount of torque make big differences. Just seemed like a lot of mechanical complexity on a pleasure boat.....nuclear sub?....Okay !

[@fjb4932]

MrWireguy, Some ask Why? and remain in the box. Others ask Why NOT? and have the Universe unfold. . . . - - - . . .

[@ingeneeer436]

Я ваши винты на валу вертел!

[@ricardoarambula27]

Hello, good solution, I am interested in interacting with people with an engineering mind, I have a mental prototype about this in vertical flight, something like a ducted fan (English is not my first language) if you are interested let me know