Reduce the power consumption of a gyroplane.

Jean Claude

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Jan 2, 2009
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Centre FRANCE
Aircraft
I piloted gliders C800, Bijave, C 310, airplanes Piper J3 , PA 28, Jodel D117, DR 220, Cessna 150, C
Total Flight Time
About 500 h (FW + ultra light)
The power profile is usually 2/3 of the power consumption to lift the aircraft. Laminar boundary layer is a good track but she seems too fragile to withstand the turbulent atmosphere, the attack angle, etc. Should we assume that all is said? I wonder.
The suction of the boundary layer absorbs much less power that she can win. The interior of the blades are nice centrifugal pumps. With many small holes judiciously placed in the upper and another hole at the tip, it might be enough?
Jean Claude
 
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I thought it was suction over the upper that we needed?
 
Yes Burdy: Upper
 
The problem with using the blades as a centrifugal pump, JC, is that pressure differential decreases toward the tips where need is greatest.

I think the pioneers had it right; keep blade loading to ~35 lb/ft² which results in a rotor tip speed of ~400 ft/second.

The Kellett KD-1 for example, flew at a AUW of ~2,000 lbs. and had a rotor blade area of 60 ft² (3 blades of 1 foot chord and 40 ft. diameter.).

Most of the modern “Dreadnoughts” operate with a blade loading of twice as much and are very, very inefficient.
 
JC
I'm a little confused???

Are you suggesting, that we introduce a reduction and/or disurbance in the boundry layer control on the airfoil????
 
Chuck,
one of the forefathers of modern gyros was the Fa330 which was built along similar principles (low disc/blade loading). If one wanted a kite gyro that takes off at even lower air speeds, what would be the problems in lowering blade loading still further (dynamic and aerodynamic ones rather than structural, the latter beeing the ones I could probably cope with)
 
I think the pioneers had it right; keep blade loading to ~35 lb/ft² which results in a rotor tip speed of ~400 ft/second.
I'm not sure, Chuck. Rotor / blades lightly loaded weigh heavy. Less power profile, but more induced drag: A comparison of the total power for the same payload: Kellet KD1: 225 HP for Passengers 364 lbs. Magni : 115 HP for passengers 364 lbs.

David, exactly. Just a thought, but Chuck is right: not enough pressure difference, where we need.

Jean Claude
 
JC
Back about 15 years ago, a friend of ours had polished his blades so slick that a fly would bust his a$$, if he tried to land on them. When tom went out to try and fly, he could not even get and keep it in ground effect. There was a bunch of suggestions for him; none of which made sence. He was instructed to take a piecs of scotch brite and scuff the top leading edge back about 2/3 of the blades. It absolutely broke his heart to do this; but after he went out and it flew like normal, the smile returned to his face.
I suspect he was loosing boundry layer control, and the airfoil was basically like a wing in a stalled condition.
 
Chuck,
one of the forefathers of modern gyros was the Fa330 which was built along similar principles (low disc/blade loading). If one wanted a kite gyro that takes off at even lower air speeds, what would be the problems in lowering blade loading still further (dynamic and aerodynamic ones rather than structural, the latter beeing the ones I could probably cope with)
Everything depends upon required top speed, Juergen.

Mu = 0.35 is a translational speed that can’t be grossly exceeded and is also the speed of maximum rotor L/D ratio.
 
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Yes Burdy: Upper
Ah, now i savvy. ;)

The problem with using the blades as a centrifugal pump, JC, is that pressure differential decreases toward the tips where need is greatest.
Wot about a few air tight baffles along the blade.
Each segment has so many suction holes on top, and an 'exhaust' hole at the bottom?
 
Birdy, you can chop and gash an airfoil until it looks like a fishbone but even though maximum lift goes up, it does essentially nothing for drag.
 

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I fly at a disc loading of 1.05, the ride may be a bit bouncy at times but the price is worth it in fuel savings and the fun factor! something interesting is how people say how quiet my gyo is when I fly over, quieter than most ultralight airplanes!
 
I suspect he was loosing boundry layer control, and the airfoil was basically like a wing in a stalled condition.
Yes, laminar boundary layer is nice for low friction, but separe off easily. In rear to the separating, it is the pressure drag. Very, very great.
A turbulent layer produces more friction that laminar but do not separate so easily. Replaced by turbulent layer, just before separating , it's the job of a good airfoil.
Jean Claude
 
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JC
20 years ago, I owned a Cessna 150 and had great deals of fun flying it. I was become very proficient playing with the fringes of the flight envlope.
One of the things I noticed with normal dusty dirty wings, was a slightly lower cruise speed at a predetermined power setting, which was an acceptable trade off for a slightly lower stall speed and lower landing speed. When I washed the aircraft and polished the upper surface of the wings, I would benefit from a slightly higher cruise speed at that same predetermined power setting and natually a slightly higher stall speed, which was really noticable at landing. The stall of the wing was more abrupt when it was clean and polished.
So I would play with this element of the flight envelope. I can only assume that the onset of a stalled condition, or the transition of the wings from a flying condition into a stalled condition, is dampened by the increased drag of the dirty condition, or in otherwords if flight is in a white area and stall is in a black area, then if the transition area is a grey area. Then I will take a little dirty induced drag anyday, so I can play low and slow.
So if a little grime will help me maintain better boundry layer control, I will gladly keepem dirty.



Hopefully, we can all learn something here with this thread.!
 
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So if a little grime will help me maintain better boundry layer control, I will gladly keepem dirty.
Which i why iv never wasted one drop of elbow grease on clean'n my blades. ;)
 
Learned pretty quick to try & keep the blades clean doing ag work in helicopters - some of the stuff we applied (fertilizers in particular) could build up on the leading edges & it most definitely hurt the performance.
 
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