Changing engine orientation

[Lee Damms]

Hi,  I've been given a damaged Priory Models Sillhouette and while this looks a very nice model I'm not keen on inverted engines.  Now somewhere on the net I remember seeing a thread stating if you don't like the engine inverted simply turn the engine mount and cowl round the other way, altering the engine thrust line will not affect the model.    Is this true or will it screw up the flight characteristics?  Should I leave well alone. 

[Doug Ireland]

Hi Lee,

 

Rotating the engine mount 180 degrees shouldn't affect the thrust line provided the centreline of the crankshaft is the same. One thing you should look at though is the height of the carb in relation to the tank.

[Lee Damms]

Hi Doug

 

Thanks for the reply,  I'll check the tank carb relationship and see if I can keep the crankshaft centreline the same before I start meddling.

 

Lee

[PatMc]

I think you'd have to lower the thrust line quite a bit or dig out some foam from the top turtle deck to get the tank high enough.

 

Here's some  some sketches I did of mine that had an old Irvine 40 in it.

 

BTW I had no problems with an inverted motor but if you really don't like that a more practical alternative might be side mounted.

 

[fly boy3]

Hi Lee, as already stated,the carb centre line and tank position is very important during aerobatic movements.Also from what I remember the sillhouette is a fast and slippery model. flyboy3.