Peter Cowan/Lexi Cameron wrote:

Does anyone out there have any data on what wing, stab and engine
incidences are on a 170/172 with a 180 engine? After checking mine, it
appears I have 7.5 deg downthrust. Seems like way to much to me but
plane has been flying great (except on floats). thanks

regards,
       Peter.

I don't know.

I would suspect a high wing uses more than a low wing.
Some low wings use about 3 degrees downthrust. The higher 
number  I think is due to the drag of the wing being 
above the thrust line.

When you put floats on it the drag of the floats is below
the thrust line of course which changes the handling. Since
this is commonly done I don't know how one deals with this.
Perhaps changing the downthrust angle is part of the float
installation procedure. In short you got me there.
 
Paul Lamar
 
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