Turbo powered pre-rotator?

[Bell430]

Ok, here goes with my idea.

I am looking at building a three bladed gyro in the 'future' with flapping/feathering bearings etc. The reason being I want to try jump takeoffs etc.

I want to ask if there are any ideas out there that involve using a standard turbo to prerotate the rotors. I am thinking of using my EJ22 exhaust plus hot section turbo to drive a 3/4 inch SS shaft to the rotor head. Connecting the hot section shaft to the 'drive shaft' by way of a heat resistant flex coupling.........

Do you think a turbo would have the ability to run up a set of blades? I can't see why they couldn't, given enough time :google: probably the only concern is the high engine RPM to produce a decent rotor RPM, also the fact that there is alot of inertia and the hot section rotor will be subject to the hot gasses for a longer period of time at low RPM...

Let me know what you think

Cheers

Paul

[Sonnyj]

Paul
First let me say, I don't have much experance with Soob, or gasoline turbos.
My experance is on diesel turbos.
Under full load RPM, the turbo shaft will be turnin in exsess of 100,000 rpm, and at that rpm, its only producing about 24 pis. I have been told and have read that a gas motor turbo shaft speed is about the same, but only makes about 7 psi.
So IMHO if you connect a shaft and a coupler and a drive gear to a set of rotors, you'll induce so much drag that the turbo won't turn freely enough to hit any where close to the boost you need to get the turbo shaft turning fast enough to get the rotors up to speed.
On top of that you'll creat so much back pressure, that you'll proly damage the motor it's self becouse the CHT and the EGT are gonna shoot through the roof.
Just my two cents.

That being said, conseder this.
You could couple a 90 deg. gear box to the end of the crankshaft or the camshaft in the Soop motor. Sure, it'ed take a little doing. Put one of those electric adjustable props on so you can spin up the rotors without pushing the brake peddles though the floor board.
Geared right you should have no prob hitting flite RRPM. I've never seen this done but it seems to me it'ed work. Wadaya thinh of that idea.
Cheers
Sonny

[russ]

Ring jerry goodwin, he was trialing 3 bladed rotors.

And prerotators.............what about hydraulic [ them little suckers sure got sum go ] your engine already has the pulleys, all ya need is a pump and a motor, some hoses.............bingo........i think

[BeefBear]

What about something similar to that which is on the latest version by Larry and the Monarch. The new pulley system employed to pre rotate. Ask Mitch if there's any info that they might share or else blow up the images and get an idea from these.

[MechFx]

Hi Paul,

There is an article in the current Gyro News magazine (Spring 2006) about using exhaust gas to turn the innards of a modified pneumatic rattlegun to assist in getting rotors up to speed. I can forward you a contact for the author if you like.
cheers
Art
(GN Editor)

[Bell430]

Mechfx (Art),

That would be great mate, ta.

Sonnyj,
Yeah, I was told today by one of our engineers that the rpm of turbos was some astronomical amount with bugger all torque.... sort of snuffs that idea out. These ideas come out of nowhere and return there more often than not.

Russel, yeah have thought of hydraulics before but they seem inherently heavy..... I will have to condider it further though.

Paul

[ajm]

re, near jump start take off, to me, a simple idea is to modify a chain saw or similar engine with a clutch, a sliding flexible extension shaft and a manual operated bendix at the head. There is an obvious weight factor but at least you have power in abundance re pre-rotateing. The manual bendix (on a heavy return spring) allows engine warm up and construction simplicity. I saw a similar arrangment on a video on this site.

ajm

[russ]

Russel, yeah have thought of hydraulics before but they seem inherently heavy..... I will have to condider it further though. Not heavy at all mate, if you source the right gear. Have 3 machines up this way with hydraulics, they are bleedin brilliant. Givis a week or 2, and i will get some pickies of em. They really get the blades howling.Trick is rotate em as fast as poss with the brakes on, then brakes off,dial on the power as well as keeping the prerotator engaged, honk down the strip and then release prerotator............works a treat. Costs were approx $1800 .
was going that way with me new machine, but have now decided to go soft start electric.

[Brian]

Russel, yeah have thought of hydraulics before but they seem inherently heavy..... I will have to condider it further though. Not heavy at all mate, if you source the right gear. Have 3 machines up this way with hydraulics, they are bleedin brilliant. Givis a week or 2, and i will get some pickies of em. They really get the blades howling.Trick is rotate em as fast as poss with the brakes on, then brakes off,dial on the power as well as keeping the prerotator engaged, honk down the strip and then release prerotator............works a treat. Costs were approx $1800 .
was going that way with me new machine, but have now decided to go soft start electric.


Will look forward to seeing the pics Russ as I reckon hydraulics are the way to go, just been a bit too heavy and expensive up till now.

[russ]

Picky of the motor up top, small as, light too. Me camera battery went flat, so unable to take more shots...........standby

This gyro is here in town, the other 2 machines are on properties, so gettin there is not on till i get me new machine in the air..............sorry.

All 3 gyros have absolutely no probs with this system..........bullit proof. The other 2 are used daily, big hrs too

[MechFx]

HI,

Contact for exhaust driven pre-rotator is
Mick Kulow
precengkulow@centralonline.com.au
cheers
Art

[Bell430]

Thanks mate..

Paul