Hubless, hingeless and bearingless helicopter rotor system

[autogyro]

I found a artical that is to say a patent of Hubless, hingeless and bearingless helicopter rotor system, the url is :http://xrint.com/patents/us/4616977
i wonder if we can use this technology into gyro rotor?
thanks
Edward.

[Arnie Madsen]

This was patented by BJ Schramm (Scorpion , Rotorway , Helicycle ) in the early 1980's and I don't know if it was ever used. The way I understand it , the rotor head & blades were formed (as one unit) out of fiberglass and used the flex of the fiberglass for pitch movement. It is like a type of the modern bearingless composite rotor heads ( Eurocopter - A-Star etc.)

Two blade systems using 1 (teeter) bearing are much simpler and easier to build for gyro's.

However , I believe the Carter Copter used a similar idea on their main rotor with good results.

Greetings from Canada
Arnie
Bell 47 G2

[autogyro]

Thank you, Arnie. Carter Copter's rotor is very nice with good performance.
Cheers, Greetings from China.
Edward.

[joe nelson]

Mornin' Arnie,

Check out the Hughes 369/500 for a hingeless system. If I remember correctly it had 16 laminated stainless steel plates for the alpha and delta hinges.

[Arnie Madsen]

Mornin' Arnie,

Check out the Hudhes 369/500 for a hingeless system. If I remember correctly it had 6 laminated steel plates for the alpha and delta hinges.
Yes Joe. My favorite hub system. Very simple. I have some drawings and will post them if I can find my book.

For anyone else not familiar with the Hughes "Strap Pack" it is essentially a set of stainless sheet metal stampings. Several of these thin straps are stacked one on top of the other and the flexability provides for feather and flap with no bearings needed.

Very simple and strong. If Hughes didnt have the patent probably the whole world would use the system ......... :) .. ???

[joe nelson]

Does the newer aircraft like the MD-530 and the Notar use that rotor system?

[tyc]

... "Strap Pack" it is essentially a set of stainless sheet metal stampings. Several of these thin straps are stacked one on top of the other and the flexability provides for feather and flap with no bearings needed.


If I'm not mistaken, N.O. Brantly tried that with his Model 305 with disasterous results; a three blade system which kept throwing off a blade or two while in flight.

tyc

[joe nelson]

Tyc,

The OH-6 I flew in Viet Nam was equipped with this rotor. It had 15 or 16 stainless steel straps that comprized the rotor head...it was said to be proof against a bullet cutting half of the straps without failure. I like any dynamic parts to be as simple as they can be. Less parts to break at the worst time....Murphy's second law:-)

Loosing a blade makes for a bad day. A few years ago a H-54 Tarhe lost a blade, just north of here, killing four and burning several homes. BAD NEWS!!