two hinged bladed rotor?

[quadrirotor]

I would like to know if it's possible to find a rotor with two hinged blades?
Thanks.

[Pierre Argh]

two bladed or two hinged?

[quadrirotor]

I am looking for a rotor like this one BUT with only two blades!

http://www.b-domke.de/AviationImages/Rotorhead/Images/1672.jpg

[Bravo73]

Er no, quadri, that one's definitely got 3 blades.

(If I'm not very much mistaken, it's the head off a H/S300).


Are we missing something in translation???

[quadrirotor]

I am looking for a two bladed rotor with offset flapping hinges.
No tilting rotor like R22.

http://www.rotaryforum.com/forum/showthread.php?t=5895

[Graviman]

Hmmm, bad idea Quadrirotor. Think about the vibration as soon as you put in a cyclic input. The rotor varies from zero pitch/roll torque to max pitch/roll torque every 180 degrees.

I like Dick DeGraws synchropter though. Any more details?
In theory you could run these with rigid or offset hinge, but in practice the pitch/roll torque fighting would destroy the machine very quickly. [ Outboard advancing actually offers better aerodynamic characteristics, at the expense of needing gyro stability augmentation. ]

Agreed with the idea of rigid gyros though - too many reduced g accidents. Why don't you consider a twin two rotor assy? For stowage the upper rotor could be turned through <90 degrees. This means there is no risk of in flight unbalancing if the rotor is not correctly fixed (look at Apache tail rotor).

Mart

[Dave_Jackson]

Here is a picture of the components in Dick Degraws rotor head.

http://www.unicopter.com/Temporary/DegrawRotorhead.jpg

Using this poor picture and the one on Degraw Hummingbird (http://www.unicopter.com/0475.html) somebody may have fun determining if the head is teetering, offset flapping, or both. The rotorhead must include lead/lag because of the cyclical Corollas effect between the two rotors.

IMHO there is no way to get an improved rotor-fuselage coupling from a 2-blade rotor (or a pair of 2-blade rotors) without generating a 2/rev vibration. However, since you seem to be interested in a gyrocopter and the gyro always has forward velocity, how about linking the tail feathers to the cyclic control? This should give a small amount of rotor-fuselage coupling. Come to think of it, isn't this how the original gyros were controlled?

Dave

[quadrirotor]

Dave, you are right: the IRKUT A002 has an elevator, but difficult to know to what it is linked...May be as the ABS of your car this is an automatic device... (may be linked to gyroscopes!!!:8 )

scroll down the page!

http://rvtpanet.club.fr/Galerie_photos/Galerie_photos_irkut.htm


You could have also this kind of stabilator!

http://www.rotaryairforce.com/

http://www.rotaryairforce.com/images/raf2000/photos/stabilator_1.jpg

[quadrirotor]

Dave, what about this one? Dick degraw made an homebuilt version of this one!

http://img335.imageshack.us/img335/7793/flettnerprincipalassy0uf.jpg

[Dave_Jackson]

Quadrirotor,

Yes. Flettner's rotorhead might have been a basis for Degraw's.

This compact assembly incorporates the power-train, the rotors, and the flight-controls.
IMHO, it conceptually represents the ability to have a certified principal assembly (http://www.unicopter.com/0986.html), upon which, homebuilt and Very Light Rotorcraft can be built.

[quadrirotor]

Yes Dave, it would be great to have this gear available for the homebuilder! any idea?:}