DONG090909 Conjecture when the rotor has forward speed

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Dan Thomas

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Sep 17, 2008
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6,991
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.
 

dong090909

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Joined
Oct 25, 2016
Messages
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Location
GuangDong China
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
 

Martin W

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Joined
May 14, 2021
Messages
209
.

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

.
 

AeroER

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Joined
Oct 6, 2021
Messages
297
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

Well-Known Member
Joined
Oct 25, 2016
Messages
101
Location
GuangDong China
.

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

Well-Known Member
Joined
May 14, 2021
Messages
209
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

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

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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disc rotor a.JPGdisc rotor b.JPGdisc rotor ellehammer 1913 to 20.JPG
 
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