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Mar 13, 2007, 04:08 PM
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JochenK's Avatar
Video

Pusher Prop Wash Compensation


Behaviour of a pusher gyro without and with prop wash compensation.

Jochen
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Jun 21, 2013, 05:27 AM
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britinoz's Avatar
Prop wash test
Jun 22, 2013, 12:40 AM
Needs More Go Fast....
MaydayMayday's Avatar
Is this an issue with wash over the tail?
Jun 22, 2013, 01:21 AM
Lou
Lou
#define answer_universe 42
Hmmm ... well my interest is piqued. After looking at the vid several times I am missing what you did to correct 'prop wash' .... but then I am about half drunk.

Nice looking model though.
Jun 22, 2013, 02:56 AM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
Quote:
Originally Posted by Obake
fter looking at the vid several times I am missing what you did to correct 'prop wash' ....
The rotation is caused by the spiral slip stream corkscrewing off the prop and hitting the vertical stabiliser at an angle causing it to generate 'sideways lift'..

Two ways you can fix it either offset the vertical stab or add thrust offset, thrust offset is best because it varies with motor power, so it doesn't upset low power/glide trim as offsetting the vertical stab would do.

If it were be I'd have offset the motor thrust line so that (looking from the rear) the motor was angled to the right slightly (right thrust). Looks like the OP decided to move the entire motor over to the right, this is another way of doing it which should work just as well, but it looks a bit odd.
Jun 22, 2013, 06:20 AM
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flypaper 2's Avatar
A little left rudder would stop it too. If it's for a gyrocopter it will need a lot of rudder at any rate.

Gord
Jun 22, 2013, 07:45 AM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
Only problem with using rudder (exact same thing as offsetting the vertical stab) is that it will only be 'right' at one power setting. One option with computer Tx's is to program in a throttle to rudder mix, that would work well.
Jun 22, 2013, 08:34 AM
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flypaper 2's Avatar
Yeah, I don't see a moveable rudder on it. Maybe weight shifting like a hanglider. Used to fly those things. You move the bar and wait for something to happen. It was great fun just the same. Lucky I didn't kill myself.

Gord.
Jun 22, 2013, 08:49 AM
Lou
Lou
#define answer_universe 42
Quote:
Originally Posted by JetPlaneFlyer
The rotation is caused by the spiral slip stream corkscrewing off the prop and hitting the vertical stabiliser at an angle causing it to generate 'sideways lift'..

Two ways you can fix it either offset the vertical stab or add thrust offset, thrust offset is best because it varies with motor power, so it doesn't upset low power/glide trim as offsetting the vertical stab would do.

If it were be I'd have offset the motor thrust line so that (looking from the rear) the motor was angled to the right slightly (right thrust). Looks like the OP decided to move the entire motor over to the right, this is another way of doing it which should work just as well, but it looks a bit odd.
Ahhh .. thank you. I see now. I looked again at the vid and I do see where he offset the motor. I was 'seeing' the back of the black mount as a shadow.
Apr 12, 2016, 05:49 PM
Registered User

Autogyro scratch build


Hi and thanks to everyone who has contributed to this thread on autogyro.
I'm going to scratch build an autogyro and have been mulling over the concept of using a cyclic pitch head from a 450 helli. I have a 2 blade flybar head and a 3 blade fbl head to choose from and will use aerobalsa blades for this build.
The post about gyros by M. Nowell, and the head used there is really good but its a fixed pitch head and I'm not sure how to transform that theory into a cyclic pitch head version.
Has anyone tried a cyclic pitch head?
Has anyone got any ideas or theory they can share?
All and any help will be much appreciated and combined with the info that has already been posted in this thread I hope this build will fly successfully.


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