Rotor revolution

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dong090909

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VTOL history is long and full of imaginative aircraft concepts that even on paper failed, concepts that went to prototyping and failed. Most of these aircraft are represented in the famous - VTOL wheel of mis-fortune published by vertical flight society. From hundreds of configurations only 3 types actually succeeded:
- the classical helicopter - the best hovering performance due to low disk loading, but it's cruise performance is lacking due to low L/D, and has limited speed due to retreating blade stall.
- Tilt wing/rotor - a compromise between hovering and cruise performance
- Jet VTOL configuration - representative harrier and F35
The last two are military aircraft, and the military specification aspect to perform the mission are the reason of their success, the economic cost being secondary, and the real reason why you don't see a tilt rotor in commercial service despite more than 20 years of AW609 development.

Some people think that electric propulsion offer advantages to bring some VTOL configuration to commercial success, and for good reasons, like high inherent efficiency, distributed propulsion and other effects, but a hidden aspect that kills the high efficiency of electric propulsion is the aerodynamics of VTOL. If the aerodynamics is not right, you end up with an inefficient aircraft, that only exacerbates the unwanted characteristics of electric propulsion - the weight and low specific energy of current batteries that for now cannot compete with fuel as a source of energy especially for longer flights.

You see, there is a problem that isn't solved yet for VTOL designs and that is making an aircraft capable of vertical takeoff and landing, having good hovering performance, but still having high cruise performance and economy. This distils to conflicting requirements for the driving parameters of cruise and hovering performance: L/D drives the performance in cruise and that means large aspect ratio wings, low wetted area and small propeller size. Disk loading and no flow interference drives the hovering performance and that means large rotors and no wings.

All VTOL configurations of today are lacking one aspect or another, there are compromises driving performance for hover or cruise, or more likely both, to be lower than what is commercially viable.

Designing an aircraft needs discipline and a fundamental knowledge of physical laws, especially aerodynamics and aeronautics, the physical laws don't really care of who are you and that you 'beat millions of people' - I guess this is a language issue - I assume the meaning is you are the best in millions?

The stories told on this forum are not meaningless - if you cannot find the meaning - your loss. If you don't want to waste your time, I suggest to start from some good aerodynamic and aircraft design books. Learn why most aircraft have long slender wings and why helicopters have large rotors.

Why do your aircraft have coaxial rotors? If for swirl recovery - it is totally meaningless. The weight and complications of the second rotor largely surpass any benefit for swirl recovery. If for anti-torque, there are better ways, especially as you have propellers. You also mentioned coaxial propellers - why? You also mentioned wings. How do you account for the destructive interference in hover, fountain lift and impingement? As I understand your concept is lift + cruise configuration, you have separate lift and cruise systems, the killer of this configuration is weight - you always have a system that is 'dead weight' not contributing to performance, but taking expensive cargo or fuel weight, how do you manage the weight increase? Do some preliminary calculations and show us how your design would perform in hover and cruise. A lot of good VTOL concepts and prototypes were 'killed' by transition performance, so keep an eye on that as well.

Once a very intelligent man said: 'Those who do not learn history are doomed to repeat it.' I think this is a very good motto for the vanabee VTOL aircraft designers of today.
Thank you very much for your patience, I see your kindness in it.
detail:
In the future, the aircraft will be compound power, and battery working time is the minimum requirement to maintain the lift and langding. The purpose is to simplify the drive section and improve the redundancy of survival.
Rigid rotor, multi-blade, means that its: lift-to-weight ratio is very high; at the same time, the rotor can be retracted to reduce the resistance of fixed-wing flight as much as possible
Rigid rotors, and multiple blades, can indeed reduce the radius of the rotor under the same load
As for dead weight, first analyze the reliability of the structural system, then the stress calculation, and then the material weight
I can beat more than a million people, which means my creativity is validated. If compared to theory and funds, I am not Sikorsky's opponent, but if compared to creativity, I am not afraid of Sikorsky. This is what I dare to do: The confidence of the second rigid rotorcraft other than the Sikorsky S97
 

dong090909

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A great part of your problem here is inability to communicate your ideas.

Such as, "suppress rotor lift fluctuations with fixed wings"; post a sketch that illustrates your concept. No one here knows.

Then, and this is especially necessary, the "the side-flying gyro effect". The model you show gives us no hint. Post a sketch of the concept. Add numbers if possible (rpm, moments of inertia, precession forces and moments, and so on). No one here is likely to steal your ideas.

Anyone can draw and yak about air vehicles with 10 kg 200kW engines and tiny wings with complex high lift devices that produce lift coefficients of 20, all in 50 kg airframes that cost the price of a 12 pack of beer that can be built under a shade tree in a couple of afternoons from materials bought at Walmart, that occurs here at least weekly. Imagination flies, physics, and especially gravity, has the last say.
I feel your motherland is China for your logic
 

Topaz

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Moderator Note: Let's all take a deep breath and step back a moment. This has turned into a snarking match.

dong090909: If you have specific questions, ask them. Listen to the answers and consider them. There are some extremely knowledgeable people here. In the long run, the best way you can prove your ideas is through calculation, a flying model, or a prototype. Simply saying that they'll work or are revolutionary isn't constructive discussion.

Everyone else: You're skeptical. You're sure this isn't going to work. Okay, not unreasonable. We've seen plenty of 'out there' ideas here on HBA. Try and help the guy learn. Provide specific answers to specific questions. Point him at reasources. Share your knowledge. Simply being one of thirty people telling him, "Your ideas won't work, it's stupid," isn't helping anyone here. Everyone here started at zero. Help them get to one. If they won't accept your help, walk away. Beating on them doesn't do anyone any good.

Thank you.
 

AeroER

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I feel your motherland is China for your logic

If you are not able to explain how your concept functions, then you cannot produce an analysis that gives the idea credibility. Understanding your own idea is fundamental, and a tiny bit of analysis will give you insight into its viability.
 
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dong090909

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GuangDong China
Moderator Note: Let's all take a deep breath and step back a moment. This has turned into a snarking match.

dong090909: If you have specific questions, ask them. Listen to the answers and consider them. There are some extremely knowledgeable people here. In the long run, the best way you can prove your ideas is through calculation, a flying model, or a prototype. Simply saying that they'll work or are revolutionary isn't constructive discussion.

Everyone else: You're skeptical. You're sure this isn't going to work. Okay, not unreasonable. We've seen plenty of 'out there' ideas here on HBA. Try and help the guy learn. Provide specific answers to specific questions. Point him at reasources. Share your knowledge. Simply being one of thirty people telling him, "Your ideas won't work, it's stupid," isn't helping anyone here. Everyone here started at zero. Help them get to one. If they won't accept your help, walk away. Beating on them doesn't do anyone any good.

Thank you.
Thank you for your pertinent point .
I back for a while
Then, I only post the progress of my work.
And I put my prototype for the whole world to judge.
thanks.
Sincerely dong090909
 

AeroER

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Good machine but nobody wanted to buy them .... same as the Mculloch J2 and Air and Space 18-A .... all gone now

Advanced autogyros approach the complication of helicopters, require lots of power, they are slow, and cost too much for their utility.

Still, they show just enough promise to attract interest and an occasional new developer.
 

jedi

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Same with the B 747 SP.

I wonder why this project has been not succesfull...
It was technically interesting, test flown and certified solution.


No need to wonder. If it doesn't perform as the company hoped it would and the customers were told it would perform eventually the truth is learned. Efficiency and performance matter.
 

John.Roo

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Same with the B 747 SP.



No need to wonder. If it doesn't perform as the company hoped it would and the customers were told it would perform eventually the truth is learned. Efficiency and performance matter.
OK, thanks.
So it means that they promissed higher than really achieved performance.
It sounds actually.
This is typical situation with practically every eVTOL project :D
 

thjakits

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Hello Dong,

models often do not justice to the (final) idea - as your design is at this moment - it is "overwhelming" to me.
Obviously your descriptions are "affected" by a less than perfect translator (...another fantastic field for endless improvements!) so some concepts might just not be understandable to us - as mentioned above - a few sketches would likely help us a lot to understand your ideas.

Now - no doubt your design is VERY complex - lots of moving parts, lots of different systems!

I do like Elon Musk's engineering philosophy:

- A Simplify! Take away everything you do not need! To the extreme point where you take away too much!
- B Do not be afraid to put stuff back in!
- C Fault of most excellent engineers: Perfecting a unnecessary part/system!! See A
- D Repeat A and B until nothing "moves" anymore!

To me it seems you try to accomplish a machine that can do everything - do you really need such a machine?

As it is, most machines today are somewhat specialized (any machine, not just helicopters!).
Most universal machines give up some performance in all areas - The V-22 Osprey is one example!
However it seems all the compromises still allow it to perform as desired by the designers...

As your design goes at this point - you need to start to shed complexity and define priorities! IF your goal is fast point to point, hover performance isn't your priority and can be compensated by increased power for short times.
IF hover performance is your primary concern - you cannot have wings.....

So - at some point you need to define the purpose of your design!
[Unless you just see it as a design/calculation exercise! But if I am not mistaken you are looking towards a patent....]

Your mention of UFOs: As far as I understand - most saucer-like UFOs are NOT saucer shaped for aerodynamic reasons, rather for supposed engine design purposes. The supposedly observed flight performances and maneuvers of these machines would indicate that their propulsion and maneuverability has nothing to do with aerodynamics at all - rather force-field control. Be it magnetic, gravity-control, particle attraction/repulsion, etc... (mostly still fiction on this planet!)

Also - history already shows where your compromises will likely be:
- The Osprey tilts the rotors and uses them for forward propulsion, but lacks performance in hover (the compromise: shorter rotors are less efficient, but still are able to work as propellers), and so far it is in a class by itself, going 300kts +
- Sikorsky x2 is betting on stiff rotors and a pusher prop - 250kts
- Eurocopter (now Airbus Helicopters), X3 - 253kts, is moving the tailrotor to the sides (forward facing propellers, for forward propulsion in airplane mode and differential propulsion in helicopter mode), also slowing down the main-rotor to the minimum stable rotor-speed and neutralizing it to zero lift which then neutralizes retreating blade stall effects.
Propellers (torque control and forward propulsion) are mounted on high-speed wings, that do not fly below 80 kts, I wonder if they could have made them even faster - likely a commercial application will stall higher, as 80kts is certainly no problem for the rotor...
[Have a close look at these machines! Look at all the moving parts on a Osprey, on the Sikorsky, on the Eurocopter and see where their speed limits and hover performance ends up.]

DIRECT suggestions from operational experience:

- get rid of blade folding/sweeping in flight! the forward speed needed for wing born flight will be a huge problem for folding rotors in flight - either they will tend to flap up or down or be heavy because of the required stiffness
- get rid of the lower rotor! It WILL get damaged nearly immediately by anything on the ground!

At present you are trying to make the theoretically perfect machine - theory is always perfect - however, real world application has to be functional! So - maybe you are not at the point yet, but eventually you need to adjust your design to become functional - then at least as functional as your existing competitors - then you need adjust it even more to become more functional than your competitors!

Good Luck!!
 
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dong090909

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Demonstration
 

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dong090909

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About the Demo
1. Since there is no relay, I used a magnet and manual instead (one of the magnets has a serious loss of magnetic force after welding)
2. Due to the use of kraft paper with weak stiffness, the entire mechanism is seriously skewed
3. The self-made coupling occupies a long distance (the couplings of the two rotors are different because the material is not enough)
4. Use a special 6MM hollow cup motor (mainly the output shaft to be customized), the entire appearance and proportions will change greatly
5. Undoubtedly, the remote control must be used to avoid ugly buttons and wiring.
 

Erik Snyman

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This video covers the topic; counter rotating rotors and props, ornithopters, threshing machines, egg beaters, and flaming butts -



This one covers most of the same ground and adds the flapping vane parasol -


Yip, and the sad thing is that each and every one of those designers/builders thought their particular machine is going to revolutionise air travel.
Erik in Oz.
 
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dong090909

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Hello all:
several questions
1. First of all, I would like to thank the website leaders for mediating and forgiving my flaws, allowing me to stay here.
A. The mainland hardly allows heated discussions because it wants to maintain stability.
B. And the airplane articles I published on the mainland, without any discussion, have all disappeared, just because I have written political theories.
C. At the same time, I would like to thank you for your politeness. Compared with the remarks of the mainland, you are very kind.
Of course, except for a Chinese who replied to my article, although he deliberately concealed his nationality, it was still exposed, and I believe he had a mission.
D. Here I have a space where I can record my work process.

2. About idiots
I don't mind people commenting that I'm an idiot:
A. If I am really wrong, then I should face it bravely and bear it, and try to correct it.
B. At the same time, comparing an idiot with an engineer’s most basic foundational ethics, I am willing to suffer being called an idiot, but stick to an engineer’s most basic foundational ethics: If I don’t understand, I won’t pretend to understand, I must understand the truth .
C. If I can't do this, I don't deserve to be an engineer.

3. About the last question
I feel like I have to be in charge, stemming from:
A. My English is too poor and there is a deviation in my expression. I just wanted to make a joke.
B. Maybe also because the Chinese culture and habits are different from yours.
C. Of course I am a mutant of the Chinese.

4. I personally think: The biggest problem is: You did not answer the specific questions I asked, but you told me many historical stories.
So, I will change the way and ask you for specific questions one by one.

Thank you.
 
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