Prop mounted co-axially on tail tube

[helipaddy]

Hi
I was reading Chucks post on the mounting and resonance isssues with the tail he has on his gyro and am wondering if anyone has thought of running the tail tube through the prop centreline. I remember an ultralight aircraft I saw somewhere with the prop mounted on the 4" tail tube with a belt drive this setup would be good with a cruciform tail on the end, allowing the swinging of a large prop on a pusher gyro.
Paddy

[Rotor Rooter]

Are you thinking of something like these?
http://www.unicopter.com/0830.html
http://www.unicopter.com/0828.html


Years ago there was a person who had partially built a craft with this concept.


Dave

[helipaddy]

Close, Dave, but I was thinking of something like this..

Paddy

[dynacure]

Here is an example.
Another interesting concept was a plane designed by Ozzy Rolf Brand.

Kind regards,
Willem

[Alan_Cheatham]

Not coaxial but boom thru prop.....

[RayPierce]

My 503 Rotax shakes too much. It would soon shed anything over a couple of feet beyond that.

I've seen trikes that tow hang gliders that have the tow line attachment with a release mechanism on the prop hub.

[helipaddy]

Yep The vibration problem from the engine was on my mind. It was just a thought anyway Thanks All
Paddy

[bowns]

Ha,did draw a sketch to present the idea one or two years ago.Thought it could rise the cg and give me a low profile.Some bushing in the right place and engine mounted to the beam(tube) to pacificate the vibra.Never sure wether I will get a frugging tail or something.Should it work,there must be lots of what to take good care of.I kept it just for fun.

[Rotor Rooter]

Why are the tail feathers on gyrocopters not located further aft, particularly when pitch stability is a concern? Kaman went from a short tail boom on the Huskie to a longer tail boom on the K-Max.

Arguments for a longer tailboom;

The tail boom can be removed for ground transportation and storage.
The rudder can be made of unidirectional fiberglass over a Styrofoam core. The angle of the fiber thread on the rudder would be aligned with the span axis of a blade during an excessively rearward flap. The blade would easily chop off an upper portion of the rudder and leave a lower portion of the rudder in place. It will be cheaper to replace a rudder than a life.
Perhaps what is first need is a gyrocopter rotor that has a greater control authority (stronger rotor-fuselage coupling) than a basic teetering hinge.

:confused:
Dave

[Doug Riley]

A fellow named Dana Junkin used to show up at the Yankee Ultralight Flyin each summer. He was from somewhere around Kittery, Maine. He'd chat with me about gyros. He had plans for a small 1-place gyro whose prop was to be co-axial with the tail boom.

On one of his last visits, he showed me pictures of the machine, well along toward completion. It probably suffered from a low CG/HTL problem, since the Rotax engine was below the tail boom and the prop drive was offset upward.

I haven't seen or heard from him in several years. I don't know if he flew the machine.

[TomCarlisle]

The prop shaft on the Gy-rihno by Dick DeGraw goes all the way through. It is a unique mounting and helps to overspin the rotor for jump take-off.