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Old 08-31-2018 | 08:30 AM
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question l have a dv8r new to me with a jetcat 80...plane flys flys good for what it is an the engine it has..the issue I'm having is a half to below 3/4 plane flys straight an level at full power she climbs...now l guess l could add a mix of down elev to solve that..but can l shim the engine...to avoid the problem almost like the ziroli turbinator like to climb at full until a thrust angle change was done..do l do the back or the front of the turbine...
Old 08-31-2018 | 11:15 AM
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Front, you want the back of the engine to point down, in flight the engine will push the plane down to keep it flying level when more trust is applied.

Last edited by CARS II; 08-31-2018 at 11:26 AM.
Old 08-31-2018 | 11:31 AM
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The DV8R is not blowing gasses under the tailplane like the BC you show, that’s the main reason the turbine is angled down on that, but it is still the front of the turbine that needs lifting.
Old 08-31-2018 | 11:39 AM
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ok thanks..I'll start with a washer an go from their..thanks
Old 08-31-2018 | 11:39 AM
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Agreed, pic is there to show the engine angle.

You may end up needing about 1/4 inch up on the front.

Last edited by CARS II; 08-31-2018 at 11:45 AM.
Old 08-31-2018 | 03:50 PM
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really that's more then I figured...think with maybe 2 washers then
Old 08-31-2018 | 03:57 PM
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Just remember that the more you angle the turbine to push the nose down at full power the harder it will be to take off. The dv8r already sits awfully flat on the gear. Pushing the nose down harder via the thrust line will make rotation more difficult.
Old 08-31-2018 | 06:15 PM
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so maybe the answer is a throttle to elev mix which should be possible on a jeti..
Old 08-31-2018 | 08:16 PM
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LGM G has a point, if you find it difficult to rotate then a partial throttle on TO my be better, then go full trust after rotation, you just have to fly the model to see what it wants to do.

Don't over think it, experiment to find a good combination of settings and enjoy and KISS it

Last edited by CARS II; 08-31-2018 at 08:23 PM.
Old 09-03-2018 | 06:11 PM
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By shimming the thrust angle you are not trimming to have the engine push the nose down, you are trimming to no longer have it push the nose up. Once shimmed for no pitch change at any power setting it will not be forcing the nose down on takeoff, just pushing it straight. If you use elevator trim to compensate for an incorrect thrust line then you will start to have trim issues while doing maneuvers. Trimming the elevator is fast and easy, but it is always better to take the time to do it correctly.

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