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Thrust angle question

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Old 04-08-2005 | 10:58 AM
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Default Thrust angle question

So I flew my glow Mini Funtana a few days ago and I noticed something unusual. It has a slight climb below 1/2 throttle and descends at higher throttle. I am under the impression that in general terms more speed generates more lift. It's slightly nose heavy. But I'm thinking I have too much down thrust at the firewall. I was only able to estimate the angles I used when I did the conversion.

Am I on the right track?
Old 04-08-2005 | 11:21 AM
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Default RE: Thrust angle question

Hmm... It sounds like you have too much down thrust and the c of g is too far back or wing incidence. Remember that the c of g around the centre of lift that speed doubles and lift quadroupls...

Kevin
Old 04-08-2005 | 12:20 PM
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Default RE: Thrust angle question

QDMG, first get the CG correct. It should be between 25-30%. That plane should fly superbly with no thrust angles at all. I would put that plane up on a flat table and do a thorough check of everything. Every surface and line should be flat, plumb and true to the centerline of the UNIVERSE!
Old 04-08-2005 | 12:39 PM
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Default RE: Thrust angle question

I measured the thrust angles from the motor mounting stick supplied with the kit and then transfered those angles to the glow mount. It is just slightly nose heavy using factory CG. This plane has two wing locations, I'm using the rear one. It's supposed to be the less areobatic more precision location.
I think I ended up with 3 degrees right and 2 down. I can check later.

CP, you think flat on the wall would be better?
Old 04-08-2005 | 01:30 PM
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Default RE: Thrust angle question

Why not measure the thrust angle and tell is what it is.
Old 04-08-2005 | 10:03 PM
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Default RE: Thrust angle question

Geistware

3 degrees right and 2 degrees down is correct.
Old 04-08-2005 | 11:32 PM
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Default RE: Thrust angle question

I fly mostly 1/2A to .15 sized stuff and have planes that will fly from here to JUPITER [straight up] with no working rudder, and zero-zero on the engine. Same goes with my .32 to .50 powered speed planes turning 8" and under props, no engine thrust. Hey for that matter, zero-zero with my Q-500 PREDATOR. Once you get into the 10, 11, 12" and larger prop zone, then right thrust is definitely welcome.You will see down thrust needed when you have a very low thrust line, or up thrust handy if you have an engine mounted high relative to where the wing is at.
Old 04-09-2005 | 08:59 AM
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Default RE: Thrust angle question

Well those motor mounts are cheap enough that I think I'll just shave it back to flat and see what happens.
Thanks for the input!

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