trying2fly
If the motor mount is mounted like the enclosed photo when the wing is launched will the motor (mounted off center) push the wing to the ground or will it cause it to rise?  The motor was inadvertently glued into this position.  Will I have to build in up elevator upon launching or will I need down?  thanx! Motor mount off center 005.jpg 
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solentlife
No ... it will tend to make wing leading edge pitch up as the motor pushes trailing edge down.

It is normal on a pusher prop to have it angled a couple degrees where bottom blade is slightly ahead of top blade. The opposite of what you have.

Why ? The wing generates lift that increases with speed - the lift tries to make wing pitch up and over ... resisted by tail, CoG and motor thrust line.
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Wildthing
Well from what I have been taught having it slightly lower should make it rise, but I think if it is just a few mm I don't think you will notice much difference. If you find it zooming under throttle you could just shim the motor no different then what we do on the parkjets if they have a zoom tendency.  If say the motor was mounted a few inches higher then the wing you would angle the motor so it is pointed at the cg mark otherwise it would want to push the nose down. 
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trying2fly
Wildthing wrote:
Well from what I have been taught having it slightly lower should make it rise, but I think if it is just a few mm I don't think you will notice much difference. If you find it zooming under throttle you could just shim the motor no different then what we do on the parkjets if they have a zoom tendency.  If say the motor was mounted a few inches higher then the wing you would angle the motor so it is pointed at the cg mark otherwise it would want to push the nose down. 
  I understand it now ....much like my Hawksky.  Thanx Jeff
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trying2fly
solentlife wrote:
No ... it will tend to make wing leading edge pitch up as the motor pushes trailing edge down.

It is normal on a pusher prop to have it angled a couple degrees where bottom blade is slightly ahead of top blade. The opposite of what you have.

Why ? The wing generates lift that increases with speed - the lift tries to make wing pitch up and over ... resisted by tail, CoG and motor thrust line.
  Thank you very much...as usual I am about 180 degrees off!! LOL
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solentlife
Not trying to be difficult - but I have never pointed motor at CoG mark ... 

With all Pushers / rear mounted props - I have always angled slightly so the prop is pulling tail UP and nose down ... to counter the pitch up tendency of wing lift.

Check out rear pod mounted models ... quite often the angle is significant ... 
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Wildthing
solentlife wrote:
Not trying to be difficult - but I have never pointed motor at CoG mark ... 

With all Pushers / rear mounted props - I have always angled slightly so the prop is pulling tail UP and nose down ... to counter the pitch up tendency of wing lift.

Check out rear pod mounted models ... quite often the angle is significant ... 


As a pusher and say on a wing type plane if my motor and prop are above the wing say 2 inches or so ,  my thrust line will be pointed towards the cg mark. 
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solentlife
Wildthing wrote:


As a pusher and say on a wing type plane if my motor and prop are above the wing say 2 inches or so ,  my thrust line will be pointed towards the cg mark. 


Ever built Polaris ? This has the motor above the wing sufficient to clear a 7" prop ... I admit it has s slight DOWNward thrust line to it - but its no more than 2 deg.
If you check out various gliders etc. with pod motors above wing - you see why I post ... 
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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