Gyroglider meets airchair?

cluttonfred

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Mike Sandlin is a longtime hang glider builder and pilot who switched over to fixed wing gliders some years ago, but still at hang glider wing loadings and speeds. The neat thing about his "airchairs" is that they can self-launch from a suitable slope with no need for a tow, though they can also be towed. (See http://m-sandlin.info/)

What about a gyroglider inspired by the Sandlin designs or the old Klaus Hill/Larry Hall Superfloater?

An electric prerotator or maybe even some sort of pull-cord system would get the rotor turning, you could even imagine that cord tied to a car or tree and letting gravity do the work as the glider rolls down a steep slope.

Of course, it wouldn't exactly compete with even a basic hanglider, but it would be a great way to learn about rotary flight.

Here are some Sandlin and Superfloater pics by way of example.

Cheers,

Matthew
 

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-willy-

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Those pics are in California. Two of them are Torey Pines, near San Diego. The white one (I think is El Mirage) must be towed into the skies.

Gliders (fixed wing) are different than a gyro glider. Gyro gliders are stones with a controlled descent. Take away what got them air born and the descend. Their lift isnt great enough to ride thermals. A thermal might decrease the decent yet you are still coming down.

If they were flown in El Mirage. They would need the anchor on the ground (car) to get air born and stay there, cut the cord and they are at the mercy of the wind.

Ever fly a kite? Get it up where the air is really pulling on the string? Cut the string (if you dare) and see what happens to that kite. Granted the gyro has the ability to chose its landing spot. Yet that kite with out the tether will eventually return to the ground (or tree).
 

cluttonfred

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Those pics are in California. Two of them are Torey Pines, near San Diego. The white one (I think is El Mirage) must be towed into the skies.

Gliders (fixed wing) are different than a gyro glider. Gyro gliders are stones with a controlled descent. Take away what got them air born and the descend. Their lift isnt great enough to ride thermals. A thermal might decrease the decent yet you are still coming down. [snip]
You're right, willy, those are at Torrey Pines, which is where Mike Sandlin is based, and I'll take your word for it on the other one. I wasn't trying to suggest that anybody would be soaring in a gyroglider, only that it might be possible to make one a little less draggy that could be used for low cost instruction or just fun from an appropriate slope, much like the old open-frame primary gliders of the 1930s.
 

okikuma

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cluttonfred

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Thanks, Wayne, I can see that great minds think alike. I have corresponded with Mike and been to Torrey Pines but not when he was there. I doubt that a gyroglider would be welcome at such sites, but there are other places to launch from. Given gyroglider glide ratios, maybe ski slopes in summer? ;-)

Related to your second thread, I would still be interested in the performance of a gyroglider with a much larger rotor blade area. If anyone can point me to fairly simple math on how to estimate the glide speed, glide ratio and sink rate for an unpowered gyro, I'd appreciate it. I'd like to play around with the numbers see what happen when you take a known design and 1) add more chord to the existing blades or 2) add more span to the exisiting blades or 3) add another blade. There might also be implications for creating a low-speed powered gyro from scratch, rather than trimming down existing models, that would be more solidly in the Part 103 ultralight category than existing designs.
 
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-willy-

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I am interested in what you find out. As I posted over in a helicopter section.... I wonder if winglets would improve the efficiency of a blade as it would help keeping the air from spilling off the tip?
 

WaspAir

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I am interested in what you find out. As I posted over in a helicopter section.... I wonder if winglets would improve the efficiency of a blade as it would help keeping the air from spilling off the tip?
Winglets are a way of getting the effect of a greater span and higher aspect ratio for a fixed wing without actually using a wider span, through reduction of the energy lost in the tip vortices. Spinning rotor blades in forward motion face very different issues, and radically different airflow and airspeed patterns than fixed wings. There have been many well-researched efforts to optimize blade tip shapes. If you would like to know more, do some google/wikipedia exploration starting with the British Experimental Rotor Programme and in particular their "BERP" tips.
 

-willy-

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Here's an interesting video of 3D modeling of the Goat by students of Virtual Design Engineering group at Poznan University of Technology.

Wayne
Alas the "goat" (although interesting) doesnt deal with making a gyro glider functional as something to attain a true glider status.
 

okikuma

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As I have mentioned previous in a different post. Rotor Disk Load is not a direct equivalent to Wing Load. If it were so, then a 600 lb gyroplane with a 1.8 lb/sq ft disk load would be able to soar and even climb better than a 600 lb Schweizer 1-26 with a 3.75 lb/sq ft wing load.

A direct equivalent to a wing load is rotor blade load and we know this because a rotor blade is a wing. Get a big enough set of rotor blades that will have 3.75 lb/sq ft blade load and the gyroglider will be able to soar.

Unfortunately, the blades would be very big and most likely too heavy, and will increase the empty and gross weights of the gyroglider making the attempt impractical.

Wayne
 
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