A friend of mine is building the electra kit, but both he & I are concerned about the seemingly excessive engine thrust angles on the plans. They put the engine centreline approx 5" up the rudder & about 3" into the left elevator. Can someone please tell me if this is correct and/or why so much of an angle on a glider when a glow powered aircraft doesn't have anywhere these angles?


ps the motor size is the recomended 550.

Hi, it seems that no one has written you back, so here goes.

I built an electra a long time ago and remember exactly what you're talking about. The reason an engine is placed at an angle is to reduce the slipstream effect from pushing on the side of the vertical stab. This is just theory of flight stuff. In fact, all planes whether models or the genuine article (ie. Cessna 150) have the engine mounted a few degrees off (on purpose).

As for the actual degree, it's related to the size, rpm, cruising airspeed, and "bite" of the prop. A propellor with less of a bite can actually be angled less. A pusher type plane (ie, a canard) doesn't require this offset since the slipstream doesn't affect any control or stabilising surface behind it!

I'm not sure how much testing Carl Goldberg did on the Electra, but hopefully it went through a few simulations and adjustments.

My balsa kit will be arriving on Friday ... so I'm interested to know if you modified it in any way, or left it alone...

Cheers.

-Patrick