Engine Mounting Problem
 

I got the Nextstar and the wrong engine an O.S. .46LA and mounted itlater found out why I was having a hard time because the engine needs modifications to work like a different mounting bracket and to shim the firewall but I mounted it without knowing what I know now or I would have got the O.S. .46AX

I trimmed the side wall so the prop don't touch but it looks to cocked to the side will this still work or do I need to get a different engine.

upload don't work here is a pic. www.diggingmetal.com/plane.jpg

Any help would be appreciated.

RE: Engine Mounting Problem
 

In size and foot print I doubt there is much of a difference between the 46 AX and LA. as far as the engine being cocked is what is called an offset.
How much off set depends on the airplane...The Nexstar is bad about pulling on takeoff.....Have an experinced pilot take it up for you and trim her out the first flight.

RE: Engine Mounting Problem
 

The 46LA weighs 12.0 oz. whereas the 46AX weighs 17.2 oz.
Both crank threads are 1/4x28.
The 46AX is 3.6 mm wider at the engine mount than the 46LA.
The 46 LA is 10.5 mm shorter. - This is why you needed to trim the cowl "cheeks" to clear the prop.

If you look closely you'll see that even with the offset the center line of the spinner looks to be very close to the center line of the fuse. Most of the time the spinner center is offset to pilot's right (aka a couple of degrees of right offset)

Have you balanced the plane with respect to its center of gravity (CG)?

RE: Engine Mounting Problem
 

No not that far yet but your correct the 1/4-28 spindle is dead center 1-1/2" from either side and I have clearance for the prop not much but it did not touch at full throttle

RE: Engine Mounting Problem
 

On the airplanes I have the spinner is centered and the back of the engine is off set

RE: Engine Mounting Problem
 

Yeah I think that might be his issue. Offset is likely built into the firewall, with the engine mount location offset to put the prop in the center of the airframe- with an engine and mount with the firewall to backplate length it was designed for.

Maybe build a spacer to make up the length?

RE: Engine Mounting Problem
 

If the prop is going to touch the "cheeks" it will likely be at idle. At full-throttle the prop is being bent slightly away from the "cheeks," so check it at idle. MANY planes have the engine offset to counter the torque of the spinning engine-mass and prop. This torque makes the aircraft want to yaw to the left, so the engine is offset to the right to counter this tendency.

This is generally not much of a problem on a trike landing gear (lg) set-up, like you have, but will still be noticeable with rapid throttle increase, especially on the ground. Just don't "slap" the stick. Apply throttle gradually. Tail-draggers, especially short coupled (short distance between main and tail gear) such as the Cub, are notoriously hard to handle on the ground due to this condition. Just keep your throttle application gradual on take-off or touch-and-go, and all should be fine. This is a good idea for any situation except for emergencies, and later on, aerobatics.

If you don't have one, find an instructor. Just go to the field you'd like to fly at and ask. Then ask your instructor for if he has any hints/requirements for your assembly/training.

The LA comes in around 1.0 horsepower (by OS spex) and the AX around 1.6. The LA should be more than ample to tug your 5# trainer about unless you are at high altitude like Denver, for instance. (Denver R/C Eagles field is at 5,500' MSL). Hope this helps, not that others haven't give good ideas already.

Best of luck!