ORIGINAL: akschu

Down thrust is when you engine points slightly down. This is because you have a flat bottom wing which produces a lot of lift the faster the plane flys. To directly cancel this lift the engine is mounted pointing down so the more throttle you have the faster it goes, the more lift you have, and the more then engine pulls the nose down to cancel it all out.

Right thrust is when the engine is pointing to the right. This is usually done by putting washers under the left engine mount or by mounting the firewall so that it points right. The reason you want this is because the prop is slightly more efficient on the left side which causes the airplane to want to yaw left as you give it more throttle. Right thrust cancels that out.

To setup the right thrust on my trainer I put a laser pointer inbetween the fins on the head ( I figure they are inline with the crank) pointing backward and when the laser points to about 3/4" to the right (looking from front to back) of the rudder I call it good.