DONG090909 Conjecture when the rotor has forward speed

[BBerson]

The multirotor things have rotors on arms well spaced out, and use RPM control for aircraft pitch and roll and vertical flight.

Right. He added those additional four rotors a few days ago on his other thread.
https://www.homebuiltairplanes.com/forums/attachments/微信图片_20220121213911-jpg.120859/

 

[dong090909]

Right. He added those additional four rotors a few days ago on his other thread.
https://www.homebuiltairplanes.com/forums/attachments/微信图片_20220121213911-jpg.120859/View attachment 120972

Thank you

 

[Dan Thomas]

Right. He added those additional four rotors a few days ago on his other thread.
https://www.homebuiltairplanes.com/forums/attachments/微信图片_20220121213911-jpg.120859/View attachment 120972

They won't help much. Those two big rotors, with no articulation or cyclic control, will present serious pitching problems as soon as the machine moves in any direction. The advancing blades will create translational lift in the front portions of rotation, while the retreating blades are flying in downwash and losing lift. Pitch-up can be expected. Roll, too, since the lower rotor will be in the downwash of the upper, making the upper more effective, and its advancing blade will lift that side of the machine more than the opposite side of the lower rotor.

But that's just my humble opinion. I want to see it built and flown, and I want to see a video of the first flight. Please.

 

[BBerson]

Pitch-up can be expected.

Right. Pitch up is very strong with coaxial and no cyclic to counteract pitch up. Something the designer should know or will learn about in experiments.

 

[dong090909]

Right. Pitch up is very strong with coaxial and no cyclic to counteract pitch up. Something the designer should know or will learn about in experiments.

Maybe you have forgotten: the fixed wing will play a great suppressing role at this time
it has a lift corridor

 

[BBerson]

Maybe you have forgotten: the fixed wing will play a great suppressing role at this time
it has a lift corridor

I don’t think the fixed wing will do much at 20-40mph. The rear lift props need to lift more to compensate. The front props can tilt and pull forward more in transition to cruise.

 

[Martin W]

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So far we have:

-- 4 wings
-- 4 propellers
-- 6 rotor blades on top
-- 6 rotor blades on bottom
-- no forward propulsion
-- no engines
-- no controls
-- no fuel tanks
-- no pilot cockpit

Dreamer with a glue gun

.

 

[BBerson]

Dreamer with a glue gun

Yeah, but the egg shells are “monocoque“. Nice touch.
Might get a $100 million in startup funds?

 

[AeroER]

One thing about this project, not even the Chinese will steal this "intellectual property", so it's safe from that aspect.

Also, all y'all are meanies.

 

[dong090909]

I don’t think the fixed wing will do much at 20-40mph. The rear lift props need to lift more to compensate. The front props can tilt and pull forward more in transition to cruise.

For AN-2, U2, or high aspect ratio aircraft, 20-40 km still works.

 

[dong090909]

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So far we have:

-- 4 wings
-- 4 propellers
-- 6 rotor blades on top
-- 6 rotor blades on bottom
-- no forward propulsion
-- no engines
-- no controls
-- no fuel tanks
-- no pilot cockpit

Dreamer with a glue gun

.

Yes, none of these, but it's good enough to qualify for the International Air Show

 

[Martin W]

Yes, none of these, but it's good enough to qualify for the International Air Show

Good luck with that.

I do give you credit for the scissors mechanism that folds the rotors ... very clever ... and if it is your invention I congratulate you.

The problem is you think you can make a helicopter work .... there are hundreds of things happening in a spinning rotor that you do not know about. It is beyond your capability .

Carter Copter used a slowed rotor to allow for high speed ..... it flaps lazily in flight (no drag) .... but it is an exotic blade that has very heavy tip-weights (depleted uranium) to keep them from bending ... it has never gone into production.

Airbus experimented with a helicopter with wings and two high powered propellers ... prototype flew but had severed harmonic vibrations from all the moving parts and driveshafts and gearboxes .... made a couple of flights and they parked it .... many millions$$$ spent by some of the worlds top engineers.

Many years before that was a helicopter designed with a large disk overhead that acted like a round wing for forward flight .... for takeoff a bunch of rotor blades were extended from the disc .... then retracted for flight ..... trouble was the complicated mechanisms to move the blades in and out weighed more than a regular helicopter .... cost more than a regular helicopter .... and ten times more complicated ..... there is a patent somewhere .... it was never built.

.

 

[Martin W]

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4540 horsepower to go 267-293 mph.

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Eurocopter X³ - Wikipedia

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[BBerson]

And those anti-torque props just feet from the cabin doors are crazy. It's no wonder why it went to a museum.

 

[Martin W]

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More disc rotors from history ..... J. Ellehammer conceived one back around 1913 when he had the first helicopter flying with variable pitch blades. (Cyclic control)

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[Martin W]

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4 second animation

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[dong090909]

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More disc rotors from history ..... J. Ellehammer conceived one back around 1913 when he had the first helicopter flying with variable pitch blades. (Cyclic control)

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View attachment 121054View attachment 121055View attachment 121056

thank you for your information.
But in any case, I will definitely let the world do a public review of this proposal.

 

[Martin W]

thank you for your information.
But in any case, I will definitely let the world do a public review of this proposal.

I hope they are as kind and gentle as we have tried to be.

Best wishes.

.

 

[dong090909]

I hope they are as kind and gentle as we have tried to be.

Best wishes.

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Thanks, I'm also ready to be: Idiot