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Ovation pitch trim in cruise


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Hi all,

Looking for feedback from other long body drivers regarding your aircraft's stab and elevator trim in cruise. 

In our Ovation with the STEC55x managing pitch, stab trim is always very nose down, yet elevator trim is slightly nose up.

From the picture, you can see the elevator counterweight protruding downward in to the air stream during level cruise.

Is this the same in other Ovations (or Bravos or Acclaims)?

Appreciate any feedback.

Hayden

VH-OVH

20201011 Stab trim in flight.jpeg

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Normal. The original design trimmed in trail. Lengthening the fuselage and adding heavier engines/props have necessitated changes to the trim system on later models. Js for instance trim trailing edge down. Long bodies trim trailing edge up. 

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6 hours ago, JT said:

Seems like this would have to be somewhat inefficient, no? 

@GeeBee is right. The effect is very small. If it were not, Mooney would have fixed it long ago. Supposedly, Roy Lopresti analyzed this during the development of the 201 and decided it wasn't worth correcting. And he was looking for every knot of improvement he could economically get. Sometimes people think this deflection creates "trim drag." But that's not the major source of drag. The tail generates a tail down force to balance the airplane. This force adds to weight and increases the amount of lift the wing has to generate. The additional lift creates additional induced drag. This additional drag is the "trim drag". Any drag from the elevator being slightly out of trail is negligible by comparison.

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