I have an alpha 60 trainer plane which has a few degrees of engine down thrust. My question is this normal for this plane? The plane was crashed and rebuilt with the down thrust alignment and I am wondering how the manufacturer sets the engine alignment. The plane does fly okay but does require more than expected down trim. Should the engine be aligned with the fuselage center line or does aligning the engine in this plane with down thrust have some purpose such as shorter take-offs or something? Thanks Wayne</p>

The Alpha 60 has a lot of positive incidence in the wing for beginners to be able to fly slowly. The downthrust might be to counteract that. You can also shim up the trailing edge of the wing to reduce the amount of positive angle. The angle is the reason for the excessive down trim. It will also probably really climb at full throttle.

Most highwing cabin types will require considerable down thrust and yes this is normal. If your airplane did not have that downthrust it would require even more down thrim power on.

Also remember most trainers use tail decaledge arrangements that are optimum for level flight at around half power. All power changes with any conventional aircraft will require retrimming for hands off flight every time a power change is made, this is also normal. A sudden power increase will cause the nose of the airplane to pitch up as will a sudden power reduction will cause the nose to drop. The down thrust will soften this pitch up effect when power is suddenly applied but will not totally eliminate it.

John

Yes there is considerable down thrust visible on the Alpha as it comes.

As already mentioned this is to counteract the climb tendancy at higher throttles and to even out the power on to power off transitions.