How many degrees to the right, should the engine be mounted, to counter the thrust given by the engine?

• Great Planes (2-piece) engine mount
• OS .46FX
• Hobbico Avistar Mk II (40)

I've mounted the engine once already, but decided to buy a second mount and remount the engine correctly, using the "thrust correcting angle", in my first trainer airplane.

The engine will be mounted flat onto the mount(s), but I want to turn it toward the right... by what... 2°, 3°, 4°, 5°... or what?

Also, the engine-mounting screws that came with the ARF, are #6 phillips head...
I have decided to use "Du-Bro" #6 socket head (allen-head type) screws instead...
Am I suppose to use washers? I bought some lock-washers, but I've not seen ANY information regarding their use (engine-to-mount).
I am using those star-type washers for the mount-to-firewall.

I want to get this finished so I can begin to break-in the new engine so I can fly my "maiden voyage" on Thursday afternoon

Thank you.

"MacAir"

MacAir,

In answer to your question there is no thrust required to the right. In fact there is none to the left. According to the specs on the Hobbico Avistar II ARF sheet on the Tower Hobbie web page there is only supposed to be a -1-1/2 degrees down thrust. If you haven't seen those specs you might want to visit that web site and have a look. It also gives some other valuable preflight checking info.

Good luck!!

Tachone,

People have said that if the engine isn't mounted slightly to the right, that the trust from the spinning propeller (or whatever) would cause the plane to tip downward to the left, requiring a counter action of constant right aileron.

Even ever-so-slightly, this would be a giant pain in the rear, being new to flying RC.

Thanks for the tip on the Tower Hobbie specs. I just looked at them and that is what it says, "no thrust left or right, just 1 1/2° down.

Hmmm... cool! Thanks!

MacAir

I applaude your decision to use socket head screws to mount your engine. Wise choice. It is not nessesary to use washers but it will give them a little more support. Lock washers are a good insurance if you are using nuts, however if you use self locking nuts as I do you don't really nead them. If you tap directly into the mount and use no nuts just a lock washer under the head will work.

You are still going to have to apply right rudder to keep the plane in a straight line while taking off. My Eagle II has lots of down angle on the engine and a very noticeable tilt to the left, but corrections are still required. Once the plane gets moving fast enough for the vertical stab to start working no further correction is required. Once your plane is in the air (in the hands of an experienced pilot right!) some "trimming" will be required to get it flying straight and level without constant control input. Your INSTRUCTOR will show you how to do this, and it is definitley not in the class of "huge pain in the ass". Now, rebuilding your airplane after a self-taught maiden flight, that's a HUGE pain in the ass.

In case I haven't been clear on this point - GET AN INSTRUCTOR!

fly the plane ,then if needed add side thrust,some planes need none, other planes need a lot.
Have a goodun,John.

Thanks guys! I'll have a goodun! (with my instructor, Stan)

Thanks!!!

MacAir