Prerotator Jet engine [Archive]

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rfonseca

10-31-2003, 11:29 PM

Pls have a look at this: http://www.rqriley.com/gluharef.html Could a jet engine be used as a prerotator in a Gyro as in the Hiller helicos in the late 50's? Ramón

quadrirotor

10-31-2003, 11:36 PM

of course you can!... as long as your neighbour doesn't shoot at you because of the noise!... ;D

DougKspokane

11-02-2003, 11:08 AM

Take a look at this: http://taggart.glg.msu.edu/gyro/evdu.htm He experimented with several different types and came up with this VERY different pre-rotator for the Gyrobee.  I don't know how it would work with "more efficient" rotors that take more energy to spin up, though.

Screw

11-02-2003, 01:25 PM

I wouldn't want to try it.  It looks like more trouble than it's worth??? What would be the advantage over the existing prerotators we currently use?

splashdown

11-02-2003, 05:47 PM

It does look like more trouble than it is worth. There is one very significant advantage however, no torque is imparted into the head plates and mast. One thing I do not like about the electric starters is that they throw in significant torque when they first start.

DougKspokane

11-03-2003, 07:02 AM

First, let me remind everybody that I'm NOT flying yet, but I've been READING as much as I can from all of you.  The main reason Taggart sights for using the "electric pre-rotator" was weight... he wants to keep the total under the Part 103 ultralight limit.  I notice that John Landry flies a Gyrobee with an "N" number, and the picture of it shows why.  It looks great, by the way, but me thinks it's a weee bit over 254#.  Taggart mentioned in the article that he tried gas engines, too, but they were hard to start and messy.  I have read other comments about the pre-rotator flexshaft creating a push against the rotor head.  To me, Taggart's solution just seems clean and simple.

gyropilot

11-03-2003, 07:12 AM

Doug K. squirted:I notice that John Landry flies a Gyrobee with an "N" number, and the picture of it shows why.  It looks great, by the way, but me thinks it's a weee bit over 254#.My Bee weighs about 300 pounds empty to be exact.

11-03-2003, 11:19 AM

*http://www.littlewingautogyro.com   Starter motors are under 2 hp at best and don't do any damage to the rotor head or mast that I can detect *in 9 years of useage. They are a bit aggressive but it seems worse than it actually is. *Engines on the rotor blades is not the answer.

rfonseca

11-03-2003, 10:29 PM

There are powerful and light jet engines in the model airplane market. http://www.wren-turbines.com/ http://www.amtjets.com/ http://www.rcturbine.com/ http://www.bairdtech.com/bmt/ http://www.gtba.co.uk/ Maybe they could bring the blades to flight rpm's instead of normal gasoline model airplane engines. Just food for thought. Ramón

Screw

11-04-2003, 02:35 AM

Back in the old days, they used a pulley wheel around the head.  Face the gyro into the wind and wrapped a rope around the wheel. Pilot strapped himself in, and a ground crew member pulled the rope spinning the rotors.  The pilot taxied up the rotors to speed and went flying. Cheaper form of pre rotator. Hey, you could use a series of pullies, keeping the rope out of the prop.  Stake the rope to the ground so you can initiate rotor spin as you taxie to the flight line ;D

Screw

11-04-2003, 02:37 AM

Wait, www.hodgeshobbies.com The Photo of the month is a 1/7th scale Bell X-1 with a larger than normal rocket engine.  Put two of those suckers on your rotors ;D

GyroRon

11-04-2003, 09:07 AM

John I believe Ernie Boyette played around with using small electric model airplane motors on the blades for a pre rotator. The power was fed to these motors with the same type of disc and contacts as your car uses to work the horn. Once the blades got to spinning on their own the motors recharged the small battery used to start the spinning. Looks like a neat cheap way to get prerotation, but I would guess the blades wouldn't get much more than 50-70 RRPM with the small motors. And if anything happened to those motors in flight the rotor could be thrown WAY out of balance!

Russell

11-04-2003, 09:50 PM

I bought the gyro with the "Airplane" motors on the rotor blades. The gyro was 1 lb under the legal ultralite weight. (253 lbs) And the blades RRPM was about 120 Russ ;D

GyroRon

11-04-2003, 11:50 PM

Wow Russ 120 RRPM? Maybe this system ought to be used more often? :o

joeheli

03-19-2004, 05:00 PM

The best way is to use the normal prerotator
whith main gyro engine a turbine ;D

joeheli

03-19-2004, 05:10 PM

I fly radio control jets and heli, I have a Stingray Jet with
a Jet cat Turbine with 16 pound of trust , they normal Jet A fuel and beliveme they are expencive. With out the tank
, pre fire system Etc, etc. the cost is $2.700. I think is to much just for spining a blade :P