ORIGINAL: flycatch
Question, I'm building an ESM ARF and the manual states that you must drop the thrust line 1/4''/6mm. Doing so puts the crankshaft center in the middle of the cowl. Not doing so and the cosmetics are upset. I took all the measurements and the thrust line should be the first mentioned. Being somewhat familiar with thrust lines and angles would this new setting act like additional down thrust?
Moving a thrust line down won't cause extra down thrust. It would cause a small change in the thrust's relationship to the center of drag of the total airframe. Moving the thrust lower compared to the center of drag should cause a more upward pitch that increases with speed.
Want an easier way to see what the situation is? Visualize what would happen if you moved the thrust line down a couple of inches. The drag would be above the thrust and the airplane would pitch up.