Helicopter rotor blades for gyro's

[BOP Flyer]

I'am not looking at using helicopter blades on a gyro, but I have heard of some people trying them ! and yes they have flown.

If they do work why do people not use them ?

Thanks for your help.

Barry

 

[scottessex]

Re:Helicopter rotor blades for gyro's

I am not certain, but I have heard that they get mounted upside down and turn the opposite way. I know a guy that has a set he has flown with. plus they are heavy.
somebody correct me if I am wrong please.

 

[Spaced]

Re:Helicopter rotor blades for gyro's

Im more of a helo gy than a gyro guy, but I thought Id put in my 2cents.
Helos do autorotate, a fact which Im thankful for every time I practice a engine out landing. All that is required is to set the atittude of the helo and air speed to get the auto going, then maintain RRPM to the ground. If you so desire once in auto you can even go backwards (very scary).
AFAIK the main difference between helo and gyro blades is the type of aerofoil used, helos use symetrical aerofoils, while gyros tend to use asymetrical ones.
Heols use a symetrical aerofoil main because of the stable center of pressure on them. Due to the high aspect ratio of a helos blade and the continually changing blade AoA, a aerofoil with a large variance in the center of pressure would cause at best a greatly reduced blade life due to fatigue, at worst loss of control.
Gyros having a fixed pitch angle can use an asymetrical blade since there is less change in the AOA of the blades.
So in answer yes they would work, but you would have to adjust the blade angle, as well as allow for the reduced lift of the symetrical blades.

(Most new helos have asymetrical blades which have either been designed with low pitching moments or use composited so they wont twist)

 

[Gordon Gibson]

Re:Helicopter rotor blades for gyro's

Phew, my first ever post.
I know of one guy who used a set of Hughes 300 blades. They did eventually go OK but the very first flight nearly ended in disaster. He took off from a grass strip in high country (reasonable take off run disatnce) but the gyro (a stock AC with 532) would not gain one inch of height. He fluttered down, down, down for about four miles - engine WOT - before flying over a road and landing in the only decent space available. After shutting down he looked back and noticed he had flown right where there should have been power lines but they had been removed only days before. He certainly would not have been able to climb over them and they were way too low to go under. However, after much tweaking he did get to do a bit of good work with them.
In a general sense the blades themselves are probably OK but if you want to use a hub system that is unproven...if anything goes wrong with this part of the machine while flying you might as well jump out. I always tell people they are better off to earn a bit more $ at their day job and just buy a nice set of gyro blades from any one of the reputable gyro blade suppliers. Then you know what you've got. Fly safe.
Safe flying is not cheap. Cheap flying is not safe.
Gordon Gibson. (btw I am not a Llama).

 

[Aussie_Paul]

Re:Helicopter rotor blades for gyro's

Welcome Gordon.

I tell everyone to make absolutely sure that from the rotor tips to the handle on the joystick, and the prop are safe. If you don't lose control of the rotor or have a prop blade go through the rotor then you are unlikely to die.

Aussie Paul.

 

[Harry_S.]

Re:Helicopter rotor blades for gyro's

Chuck Beatty and a cohort or two played around with Hughes' blades back in the late 60's or early 70's. They flew them but I think the opinion was, "it ain't worth it"

I do believe Chuck had wrote this up in the PRA mag.

 

[Doug Riley]

Re:Helicopter rotor blades for gyro's

Both Hughes 269 and Hughes 300 blades were in use on gyros in the early-mid 70's in Florida. They had helo-type twist (same as washout on a fixed-wing) and they had to be turned upside down to get the twist correct for a gyro (higher pitch at the tips... sorry, Paul Bruty). Some folks used them with the built-in tip weights while others sawed off some or all of the portion containing the weight.

These blades were quite difficult -- perhaps impossible --to hand-start. They flew well once they were brought over their "hump" speed with a prerotator. In drag tests, they proved out as well as or better than the good brands of metal blades then available. Best of all, they were either cheap or free, since the gyronauts scrounged blades that were timed out from helo use.

I don't know if you can get these discards anymore. The world isn't quite as casual as it used to be, and helo operators may be paranoid about liability. If someone wanted to use them and could find a set, I imagine that one of the Florida oldtimers could share the plans for the hub.