Rotor revolution

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dong090909

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Nice machine!
Concept reminds a bit the NASA AD-1 'Scissor wing', having an antecedent, what not, in a German WW II project.
The X-50A Dragonfly has a round section in center of rotor, that perhaps would make the effect of shortspan wing root, high sweptback supplement that made from the Me.P-1101, and its copy Bell X-5, antecedent of F-111 'Aardvark', a flyable airplane.
There was even a Triangle shaped rotor, with moving tips, intented to take off as 'Helicopter', and act as a Delta wing planform at supersonic speeds.
Aerodynamics is same for all, materials, too, solutions for a certain flight envelope cannot be very different.
By repeating research in designs that failed, sometimes the fault is found and problem solved, but: Who has the resources, manpower, money, time, to test-retest everything?
Blassings +
If you do as the great Skooski in rigid rotor thinking, it is definitely what you said: resources, manpower, money, time. . . . . .
If I change my idea: dead together, let the world to review, how do you estimate the consequence?
Even if he has never heard of: China Kung Fu, surprisingly winning, and at least heard the quotation of the West Point Military Academy: Asymmetric play
 

dong090909

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When you get an idea, How do you know you're the only guy who had it first? :fear:

When I was training at Bell (maintenance 212) I would sneak & hop in the simulators at lunch time, Got to meet an original Bell guy.
I'll call him Frenchi - Instead of ratting me out to management he climbed in and we enjoyed a time of screwing off and seeing how small a pad we needed for an autorotation. He said I was the only person to do a full down auto in this sim 1st try. then We landed on the tower, hangar, sheds and the top of a pine tree.

All week long at lunch time we'd have fun. Never had to reset the machine. His stories of Old Bell was great,
He said the New Bell wasn't as fun as the Old Bell...

We learn from history spoken from old wise men.
I do It , and it‘s better’ than I say it. Let history proof
 

dong090909

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GuangDong China
Before someone can improve on the helicopter, he has to understand helicopter theory. There is so much more going on there than most people---even fixed-wing pilots---realize. And it's done that way because that's what works.

There were many, many attempts that did not work, and the refining process was like panning for gold: you dump a lot of sand and gravel and water into the pan, slosh it around, and gradually spin off the stuff that isn't gold. The helicopters we see today had many evolutionary ancestors.
I do It , and it‘s better’ than I say it. Let history proof
True of many companies in many different industries.


BJC
True of many companies in many different industries.


BJC

Before someone can improve on the helicopter, he has to understand helicopter theory. There is so much more going on there than most people---even fixed-wing pilots---realize. And it's done that way because that's what works.

There were many, many attempts that did not work, and the refining process was like panning for gold: you dump a lot of sand and gravel and water into the pan, slosh it around, and gradually spin off the stuff that isn't gold. The helicopters we see today had many evolutionary ancestors.
I do It , and it‘s better’ than I say it. Let history proof
 

AeroER

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Joined
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Messages
294
dong090909

Tell us the most fundamental principle of lift generated by a rotor (or propeller).
 

Martin W

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May 14, 2021
Messages
209
what do you think: coaxial rigid double rotors, when in the same phase, the lift difference is the smallest,
it is the keypoint of this craft
.
dong090909 ... most of your ideas have been tried many times before

For practical reasons most of them were abandoned

Stanley Hiller built a rigid-rotor co-axial in 1944

.
hiller co-ax.JPG
 

AeroER

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what do you think: coaxial rigid double rotors, when in the same phase, the lift difference is the smallest,
it is the keypoint of this craft
Your model does not have coaxial rotors. Do you understand that rigid rotor helicopters aren't rigid? They exploit the flexibility of engineered beams that control flapping, leading and lagging motion, and pitch change due to aerodynamic torque.

Stability augmentation for model flying machines is cheap and available now, you should get an example flying in 2022 to prove your concept.
 

dong090909

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Joined
Oct 25, 2016
Messages
101
Location
GuangDong China
.
dong090909 ... most of your ideas have been tried many times before

For practical reasons most of them were abandoned

Stanley Hiller built a rigid-rotor co-axial in 1944

.
View attachment 120636
At least one thing is for sure: no one has tried:
Use fixed wings to suppress rotor lift fluctuations
Side-flying gyro effect to stabilize rigid rotors
Like flying saucers, rigid rotors above and below the fuselage
. . . . . .
I can't find any evidence either. Someone mentioned that: the lift balance condition of the rotor with reversal of the shaft or common axis: the upper and lower rotors are in the same phase.
 

dong090909

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Joined
Oct 25, 2016
Messages
101
Location
GuangDong China
Your model does not have coaxial rotors. Do you understand that rigid rotor helicopters aren't rigid? They exploit the flexibility of engineered beams that control flapping, leading and lagging motion, and pitch change due to aerodynamic torque.

Stability augmentation for model flying machines is cheap and available now, you should get an example flying in 2022 to prove your concept.
I will provide the model to the whole world to judge, I can afford to lose, in Chinese: I am a rogue who I am afraid of.
 

D Hillberg

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Joined
Nov 23, 2010
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very low low low earth orbit
At least one thing is for sure: no one has tried:
Use fixed wings to suppress rotor lift fluctuations
Side-flying gyro effect to stabilize rigid rotors
Like flying saucers, rigid rotors above and below the fuselage
. . . . . .
I can't find any evidence either. Someone mentioned that: the lift balance condition of the rotor with reversal of the shaft or common axis: the upper and lower rotors are in the same phase.
Actually a Boing 347 was modified with wings and fly by wire controls - the machine was at Fort Rucker in the 80s in the Museum grounds... Larger than a Chinook and 4 bladed rotors - tested wing and rotor interactions.

Looks like you should scrounge the local R/C toy shops and up grade to a flying example.

 
Last edited:

dong090909

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Joined
Oct 25, 2016
Messages
101
Location
GuangDong China
I don't want to answer one by one.
Your dissuasion will only arouse my fighting spirit.
Maybe you are all great, but do you know who I am? I once beat millions of people by myself, do you have this kind of performance?
The most important thing is that you did not attack the core of this plan, but told a bunch of stories, meaningless.
I tell you what to attack:
Condition for lift balance of rigid twin rotors with coaxial reverse propellers
Is it feasible to suppress rotor lift fluctuations with fixed wings?
Is the side-flying gyro effect feasible?
Does the structure have fatal flaws?
. . . . . .
Other than that, I don't want to waste my time
 

Dusan

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Joined
Sep 15, 2014
Messages
201
Location
Canada
I don't want to answer one by one.
Your dissuasion will only arouse my fighting spirit.
Maybe you are all great, but do you know who I am? I once beat millions of people by myself, do you have this kind of performance?
The most important thing is that you did not attack the core of this plan, but told a bunch of stories, meaningless.
I tell you what to attack:
Condition for lift balance of rigid twin rotors with coaxial reverse propellers
Is it feasible to suppress rotor lift fluctuations with fixed wings?
Is the side-flying gyro effect feasible?
Does the structure have fatal flaws?
. . . . . .
Other than that, I don't want to waste my time

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.
 

AeroER

Well-Known Member
Joined
Oct 6, 2021
Messages
294
I don't want to answer one by one.
Your dissuasion will only arouse my fighting spirit.
Maybe you are all great, but do you know who I am? I once beat millions of people by myself, do you have this kind of performance?
The most important thing is that you did not attack the core of this plan, but told a bunch of stories, meaningless.
I tell you what to attack:
Condition for lift balance of rigid twin rotors with coaxial reverse propellers
Is it feasible to suppress rotor lift fluctuations with fixed wings?
Is the side-flying gyro effect feasible?
Does the structure have fatal flaws?
. . . . . .
Other than that, I don't want to waste my time
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.
 
Last edited:

D Hillberg

Well-Known Member
Joined
Nov 23, 2010
Messages
1,684
Location
very low low low earth orbit
I don't want to answer one by one.
Your dissuasion will only arouse my fighting spirit.
Maybe you are all great, but do you know who I am? I once beat millions of people by myself, do you have this kind of performance?
The most important thing is that you did not attack the core of this plan, but told a bunch of stories, meaningless.
I tell you what to attack:
Condition for lift balance of rigid twin rotors with coaxial reverse propellers
Is it feasible to suppress rotor lift fluctuations with fixed wings?
Is the side-flying gyro effect feasible?
Does the structure have fatal flaws?
. . . . . .
Other than that, I don't want to waste my time
Fight? The only things you fight are ; Gravity , Material limits , Drag , Father Time and Family.

Take what your given here as a challenge to learn, Not only with what works but what has failed.
04_20_18_462_attachment.jpg 100 conversion kits
don-hillberg-skyshark-rotormouse-helicopter-777x437.jpg
All started with the yellow thing
1aad07c6b04f547caa2146785a10dc05e4bf90c6350772cfc0b74298c041d5dc.jpg
 

Martin W

Well-Known Member
Joined
May 14, 2021
Messages
209
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.
.

Best post on this whole thread ... thank you

.
 

AeroER

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Joined
Oct 6, 2021
Messages
294
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 -

 

cblink.007

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