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  #1  
Old 02-09-2017, 01:55 PM
jeffwill jeffwill is offline
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Default Gyro with roll cage - any examples?

Hello,
Are there any examples of 1 or 2 place pushers with a 4130 (say) roll cage
for the driver and some kind of basic covering like fabric?

I'm thinking of something like a eurotub that replaces the keel structure
and plastic with a space framed cockpit and some lightweight covering like
fabric the idea being get a similar weight to a keel + composite thing with the
advantage of better rollover protection and ease of fabrication at the
expense of worse aerodynamics and a lot of ugly.

Any pointers to prior art or arguments against welcome.


j
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  #2  
Old 02-10-2017, 07:43 AM
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Brian Jackson Brian Jackson is offline
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I believe the Bandit had a roll cage type of frame, though uncovered. I seem to recall from photos. My first thought in engineering what you've described would be to estimate the extra weight penalty, and also where the weight is added in relation to the CG of the ship. Adding weight below the CG is typically not desirable in a conventional design. But many do seem to fly very well provided there is adequate HS and other balance/aerodynamic accommodations. I can't answer from experience or authority, so I'll be interested to read others' comments.

Brian
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  #3  
Old 02-10-2017, 09:19 AM
Richard Anderson Richard Anderson is offline
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Barnett's J4-B2 has a welded steel tube structure that might be modified with a cage, but it is no longer available. Might find a used one that could be modified. The best way to get a cage,IMO, would be to just build a tractor like a Little Wing.
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Old 02-10-2017, 09:24 AM
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Default Some Thoughts on a gyroplane roll cage.

Gyroplane safety in a crash is a touchy subject because there are so many ways to die when a gyroplane runs into the ground hard.

If the mast remains intact it may work to protect the pilotís head if the aircraft becomes inverted something like a roll bar.

In The Predator there is a truss on either side that provides some side impact protection. It is low and a lot of the pilot is still exposed. The rotor mast is also a truss and may provide some roll over protection.

A little wing has a fairly complete enclosure that may help in minor mishaps. A tractor may be considered better in a front crash because the engine is in front and can absorb energy and knock small things out of the way.

In most pushers the pilot is between a frontal impact and the engine and some suggest it is not ideal to be the first thing to arrive at the accident in a frontal impact followed by a heavy, hot engine.

I feel the best way to mitigate the risk flying a gyroplane is to build a stable gyroplane, learn how to fly it well and take care of it.
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Old 02-10-2017, 10:06 AM
EdResnick EdResnick is offline
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Regarding your last point, in a gyro I believe it's always better to crash-land vertically rather than horizontally if you are unable to do a proper landing.
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Old 02-10-2017, 10:49 AM
Jean Claude Jean Claude is offline
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I do not agree, Ed
The descent rate in vertical flight is about 28 ft / s, while the rate of descent is about 14 ft / s during a glide to 40 mph
So, except a tree in front of it, much more likely that the energy dissipated in the autogyro will be only in proportion (14/28)^2 , ie four times less.
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Old 02-10-2017, 11:09 AM
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While the effectiveness could be argued, the Bensen geometry is based on triangles which, if all the tubes remain intact, offers a safe space for the pilot during a rollover. Your arms and legs are still vulnerable, but there is some protection for the torso.
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Old 02-10-2017, 11:11 AM
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rather have the engine going into the dirt then through me. If you cant get to zero air speed and zero sink rate as the wheels touch maybe you better find something else to fly.
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Old 02-10-2017, 11:43 AM
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Default Some thoughts on crashing The Predator.

Quote:
Originally Posted by Jean Claude View Post
I do not agree, Ed
The descent rate in vertical flight is about 28 ft / s, while the rate of descent is about 14 ft / s during a glide to 40 mph
So, except a tree in front of it, much more likely that the energy dissipated in the autogyro will be only in proportion (14/28)^2 , ie four times less.
The Predator in a vertical descent sees about 1,200 feet per minute (20 feet per second or 12kts) and in an engine at idle glide at 50kts I might see a descent rate of 900 feet per minute (15 feet per second or 9kts) and 1,000 (16.6 fps or 10kts) is not unusual depending on conditions.

If I had a choice on a dark night I would probably go for a vertical descent to the ground because of my fear of wires, trees, fences and buildings.

If I was confident there was nothing to hit I would prefer forward speed for a chance to flair and reduce the descent rate.

I feel that hitting something solid at 50kts indicated air speed would be worse than a vertical descent to the ground even at 28 feet per second (1680 feet per minute or 16.8kts).

In a water landing; particular at night I would opt for a near vertical descent.

I feel there is value in thinking about such things before the situation presents itself.

I seldom fly at night and don't fly far over water.

I feel the best approach to mitigate the risk involved if flying a gyroplane is to fly a stable gyroplane, learn to fly her well and take care of her.
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  #10  
Old 02-10-2017, 01:22 PM
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I have dropped vertically from altitude when it was the safest option, one on hard ice when open water or tall trees left it as my best choice, I wasn't hurt but I did bend a few things on the gyro, the other was an engine failure in poor visibility and there would be no way to tell when to flare, I aimed for the north shore of a pond where I knew the snow would be deepest and did a vertical decent into four feet of soft snow, no damage but retrieving it involved a lot of digging.
Norm.
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  #11  
Old 02-10-2017, 02:37 PM
Jean Claude Jean Claude is offline
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Vance, I think your vertical downhill rate is too optimistic, because it's hard to estimate the actual verticality when you're far above the ground. Remember that with a slope of 45 degrees, this makes only 16 mph horizontally.

The carefully checked experimental results have always revealed that Cd rotor <1.6 for AoA = 90 degrees
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Old 02-10-2017, 02:56 PM
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It sounds like a roll cage isn't gone to help with a forward or near vertical crash,

therefore having one is not as important as say, better training to help reduce injury or

gyro damage.



Best regards,
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  #13  
Old 02-10-2017, 03:09 PM
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I once landed vertically in a gyro because there was no other choice.

I was doing first flight tests for a Bensen type gyro that had been built by a young man serving in the US Coast Guard when the complete vertical tail broke off.

A forward glide was impossible and I had to switch off the engine to prevent rotation of the gyro due to edgewise flow through the propeller.

I landed square but the gyro flipped over on the bounce and rolled itself up into a ball. My only injury came from being wallowed about in a bed of sandspurs*.

* http://www.shellkey.org/what-is-a-sa...andbur-anyway/
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Old 02-10-2017, 03:20 PM
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The Butterfly long travel suspension would work good to cushion a vertical descent.
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Old 02-10-2017, 04:00 PM
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Chuck , if there had been even a few inches of snow on the ground those nasty sand Spurs would have been completely covered and you would have had no discomfort at all.
Norm
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