autogyro hang glider

dmjc66

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There's a video on Youtube showing an autogyro/hang glider, built & flown in the nineties by a rather brave Russian.
I understand the drag is relatively high, in gliding flight:
so can anyone tell me how much thrust is required for an autogiro of a given weight and rotor diameter & number of blades to maintain level flight?
I am new here, but I am hoping someone can enlighten me, perhaps by relating this to glide angles or something.
Dave
 
Do you have the link to this video?
 
I'm new here

I'm new here

Yes his helmet was heavy but not as heavy as his balls which were described as being as big as church bells.
Seriously though I was trying to determine if this in fact was the lightest way to build a gyro-glider.
Presumably the rearward lift vector of the rotor disc, needs to be overcome by enough thrust to 'maintain' forward speed through the air.
If anyones familiar with paramotors (prop/backpack for paragliders) I wonder if that would have sufficed????
Dave
 
A good gyro rotor has a lift-to-drag ratio of about 5.5:1. Poorer homebuilt ones are down around 4:1.

Rogallos were in the same range, I believe. Newer hang glider wings are much better.

If a lifting dievice has a lift-to-drag ratio of 4:1, that means it makes drag equal to 25% of the lift that it makes. During one-G flight, then, the drag of the lifting device will equal 25% of the aircraft's gross weight.

Of course, there's additional (parasite) drag generated by other parts of the aircraft and the pilot's body.
 
thanks

thanks

Cheers Birdy for the video I wonder if the wind penetration could ever be improved enough to dispense with the motor altogether? (and 'soar' *off a tow).
Thanks Doug for the 'glide ratio' which makes me think it could.
Dave

(by *soar I mean ride the winds vertical movements like a glider.)
 
I cant see why not.
Theres plenty of thermals round ere that you can idle on with a powered machine, but you gota stop, coz it dont take long to fly outa it again.

Plenty of times iv been playn round wen things are quiet on the ground, find a screamer and power off and do a virtical decent, but ususly end up climbn virticaly.
Dont take long to go past my ceiling.
 
safety

safety

Although not a glider but a kite (as it was towed by submarine) I think the Focke-Wulf Fw 186, autogiro reconnaissance aircraft employed a jetisonable rotor, which was replaced by a canopy if ever those blades were to stop turning.

I dont kow how the pre-rotation was achieved.

But with some pre-rotation it might be possible to soar straight off the slope (foot launched) ??
 
Doug.
Thanks for the very lucid answer above.
On the same topic, how does the actual number of rotors (not blades) affect glide angle (or as you put it L/D) please?
Dave
 
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Dave:

Terminology?

Each set of rotating wings on a single axle is one "rotor." Each wing on a rotor is a blade. A rotor may have one, two, three or more "blades," but it is still one rotor.

A few people have built one-bladed rotors (with a counterweight mounted opposite the one blade), but they have vibration problems caused by the difference in lift and drag between the weight and the one blade.

Two blades are likely to be the lightest and simplest arrangement. By eliminating hinges (other than a teeter hinge), two-bladed rotors eliminate weight, drag and cost. A two-bladed rotor is probably the best arrangement for a light gyro.

I have no information about true multiple rotors in autogyros. This arrangement is likely to be heavy and complex, and to have unique stability challenges, making it unsuitable for a very light craft.
 
Dave - You're welcome to come up to St. Merryn and try it for yourself on my B8 glider. They 'glide' in the direction of down, but great fun. It's a bit manic at the moment as I'm trying to get my Cricket ready for the best gyro meet of the year (Bois de la Pierre - plug :yo:) at the end of May, but you're very welcome to come look see.
 
... anyones familiar with paramotors (prop/backpack for paragliders) I wonder if that would have sufficed????

Look like it have been done with 2 big paramotors.
__________________________________________

Dave - You're welcome to come up to St. Merryn and try it for yourself on my B8 glider…….. great fun. …
…… ready for the best gyro meet of the year (Bois de la Pierre - plug :yo:) at the end of May…..

If it where possible to have a try in a gyroglider or even simpler, in a 2 seated boom-glider, I think you would get some new people interested in rotor craft :peace:
 

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Thanks Rotormouse & Doug.
I was in fact familiar with the notion that one rotor was that which is attached to each hub/axle. Also that one rotor was one or more blades.
I find it interesting that you perceive 2 rotor discsto be more complex.
Getting to the point. I was actually querying how the 'number' of rotor discs in effect affected induced drag? (it may be heavier of course, but draggier?).
In very general terms, a biplane has more induced drag, once out of ground affect, because it has 4 tip vortices (wing tips) = more drag.
But 2 discs? (assuming the same number of blades and loading).

Thanks Rotormouse. I'm not alone on this island then. St Merryn is near to Newquay. Do you fly the Cricket from here Rotormouse? Also if I were to breeze by, when's best?

Jens, I appreciate your sentiment. Is that a paramotor powered gyro, in the photo? I was actually however more interested in the use of weight-shift and the ways of dispensing with drag & weight this intrepid Russian has addressed in such (I thought) a unique way. He is flying 'prone' & the uprights and base bar could be streamlined just like a hang-glider, if necessary.

Dave
 
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Dave:

A rotor disk has trailing vortices not unlike a fixed wing. Any device that accelerates air downward will tend to have such vortices.

In general, airfoils become relatively more efficient as they get larger (the Reynolds number effect). Therefore, you can expect a twin-rotored gyro of a given weight to be less efficient than a single-rotored one, since the rotors are apt to be smaller.

Keep in mind that, since a gyro rotor has a L/D of perhaps 5, weight is MORE important to gyro performance than it is in the fixed-wing context, where L/D may be 30, 40 or more.
 
Thanks for your kind consideratrion of this aspect Doug.
Presumably someone has made some comparative studies of the L/D of rotor disks, in relation to number off.
The trend since its inaugeration has really been away from 2 rotors.
But I wonder if thats simply fashion. On the grounds that compactness had become one of the gyro's main virtues, and it had become clear, on the same grounds of compactness, that the same or a better degree of control could still be achieved using much shorter moment arms (aerodynamic levers), by blowing air over the control surfaces.
I'm not certain 2 rotors of the same disk area, is necessarily heavier than 1, as that surely would depend upon the design.
Dave
 
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...I'm not certain 2 rotors of the same disk area, is necessarily heavier than 1....

And when you look at the pictures..? ;-)
 

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