Simple Rotor for Homebuilt Helicopter

[Rotor Rooter]

The first of the following two pages shows a very simple rotor for a helicopter, which might be of interest. It does not require a swashplate. It appears to be only slightly more complex then that of a gyrocopter rotor, considering what it is capable of doing.

The second page is the notes that accompany the diagram.


www.SynchroLite.com/Temporary/RotorHunt2.html

www.SynchroLite.com/Temporary/RotorHunt.html


Any thoughts?

[Victor Duarte]

Hi Dave,
interesting design but quite "old-fashion".
in addition, hydraulics..hum...
isn't there a way to do simpler with the new materials ?
i mean you could imagine a flexible hub around a spherical wear, or kind of.
thanks

[Rotor Rooter]

zeeoo,

I agree. It is old, but what looks appealing is that when you exclude the collective, it is functionally the same as a current gyrocopter's rotorhead with a centrally located prerotor.

In other words it is simple and inexpensive. Just as important, is there any reason why the above would not be acceptable right now as a gyrocopter in the Sport Plane/Pilot category?

The next furture step would be to simply to add the collective.

The appeal of the collective is that;
~ It has very elementary hydraulics.
~ It has a spring to drop the blade pitch, should the hydraulics fail, and
~ a simple automatic governor could be added at some later date, if desired.

[autorotate]

these pics are from "pioneering with sikorski" the book is full if there initial ideas ,none preceding the vs300 were practical enough to be used

[Rotor Rooter]

autorotate,

..initial ideas ,none preceding the vs300 were practical enough to be used The early ideas that were used in the vs300 weren't very practical either. For example the use of 3 tail rotors instead of main rotor cyclic control.

This is a later idea. From the text, it appears that this 'invention' is the work of the author, William Hunt, and that it was done after he left Sikorsky after having worked on the XR-5 and 6.

[rtfm]

Hi Dave,
interesting design but quite "old-fashion".
in addition, hydraulics..hum...
isn't there a way to do simpler with the new materials ?
i mean you could imagine a flexible hub around a spherical wear, or kind of.
thanks
Zeeoo,
Hi. I'm not sure if I have this right... It seems to me that one of the reasons we don't see collective pitch control on gyros is that it is too complex/expensive for most folks to live with comfortably. I have to admit that the head described here is far from simple to me, and I would have thought quite expensive to manufacture also. As for old-fashioned, I wouldn't know...

You allude to simpler ways to acomplishthe same thing, yet I don't recall reading about anything which would satisfy the typical gyro enthusiasts lust for simplicity.

I would REALLY like to add collective to my new gyro - but I just can't find any way to do that without fitting a light helio head, swash plate etc.

Is there any help on the horison, or am I barking up the wrong tree?

Regards,
Duncan

[Victor Duarte]

Duncan,
adding collective on a teetering head asks for a re-engineering or at least re-design but you don't necesserly need a helo head.
maybe something like this sketch. but shure you will need blade pitch adjustment.
when i say simple, i refer to C.Beaty's rotorhead. On an helicopter, the hub needs to be linked to the engine, in a gyro it doesn't, so you don't really need an universal joint, just a system that allows the hub to be aligned with the rotor disk , like soft couplings.
sorry i have not C Beaty's rotorhead, you should have a look a it.
regards.

[Victor Duarte]

zeeoo,
~ a simple automatic governor could be added at some later date, if desired.

i will post a thread about a rotor governor a friend built and flies.

[Jim]

Dave,

Any more pictures that you can scan from the book these came from?

Thanks

Jim

[Rotor Rooter]

zeeoo,

I think that the commonality of the gyrocopter head and this head is that they both have; a universal joint (i.e. 2 hinges at 90-degrees to each other), a rotor rotational bearing located above the 'universal-joint', and two control rods.

The thinking is that of initially only building the gyrocopter aspects of the head, but designing the head so that it can incorporate the additional features, in a series of progressive steps, in the future. If each incremental step was acceptable to the FAA then eventually they would be accepting a helicopter. Of course, the tail rotor vs. twin rotor problem must be eventually addressed.
_____________________________

Jim,

I have not yet finished reading the book, but if other interesting pictures appear they will be scanned and posted.

The pictures on this posting (http://www.rotaryforum.com/forum/showthread.php?p=93249&highlight=Hunt#post93249) were from his book. If there is something that you would specifically like to see, just say so and I will post it.

Dave

[Victor Duarte]

Dave,
i fully understand what you try to do, and i must admit thet i, also, would do like this, try to build a head for a "cheap" gyro but keep in mind the possibility to upgade it for helo use... i also like evolutive designs. way to go.
At least , here, we can fly a gyro with a full cyclic feature, nothing forbidden excepted overweight... ow you guess what i have in mind...
something like : build a gyro with a cyclic....add a collective, it's still a gyro.... add something like tip-jets prerotation...it's still a gyro.... give full power from prop to rotor.. and it's not a gyro anymore.
My concernis : is it cheaper to build a cardan joint ? and an hydraulic piston ?
maybe, maybe not.

[Rotor Rooter]

The first posting in this thread has a link to a drawing of Hunt's simple rotorhead, plus a link to his text that relates to this rotorhead. I have just added the balance of the text, which was not included at the time of the original posting.

If simplicity is paramount, why could not a Bowden cable be used to control the collective? Then if a governor was desired at a later date, the cable could be replaced by a hydraulic system.