Right and down thrust on arf please help
 

I am currently building a Phoenix Extra 300S ARF. I have had 4 or 5 planes and always either bought them used and built or had a flying buddy help me build them. This will be the first one I did by myself. The engine mount comes preinstalled on the plane does that mean the right and down thrust is already "built in" or do I have to do it myself. If so how do you do it without all the special tools they make for it. It calls for 1 degree down and 5 degrees right the engine mounts at 90 degrees. Also the control surfaces come preinstalled they look like they have plenty of glue and are very strong should I try and add more glue to reinforce or should they be ok. Thanks for any help I would really like to get to where I can build a plane by myself without worries.

RE: Right and down thrust on arf please help
 

Just look at the firewall. It would be obvious if some thrust angle has been added. The mounting holes are usually off center to make up for the thrust angle and the firewall would not be perpendicular to the center-line. This allows the thrust washer / prop to be on the center line of the fuse when thrust angle has been built in. Most ARFs already add the thrust angle for you. If you ever have to add thrust angle, you can do it using washers between the engine mount and firewall as follows: With the nose pointing at you, add two washers to the upper right, one washer to the upper left, one washer to the lower right and no washers to the lower left. This gives you some down and right thrust angle. Go back and do this after the engine has been mounted because the engine and engine mounts must move together as one unit when shimmed.

RE: Right and down thrust on arf please help
 

Thanks

RE: Right and down thrust on arf please help
 

also dont forget to re-adjust the throttle linkage after adding washers (or ernst thrust plate) because the linkage adjustment will change.

for ernst thrust plates, click on link below.

http://www3.towerhobbies.com/cgi-bin...late&search=Go

RE: Right and down thrust on arf please help
 

If it ain't broke, don't fix it. ;)

RE: Right and down thrust on arf please help
 

Most all ARFs these days already have built in thrust angles based on the recommended engine sizes and other factors. Deviations from the planed engines, will call for slight changes in thrust among other things, but if you stay within their recommendations, you should be fine. Even if it is a little off, it won't be unflyable, it will just require more trim and quicker responses on fast power changes.

If you can't tell by looking, after you have your engine mounted and the prop installed, measure from each prop tip back to the back of the vertical stab (not the rudder). The measurement on the right side should be slightly less than what you get on the left, if the factory set it up for you. If they are the same, just add washers under the left half (about 2-3 deg is good usually). I don't use down thrust on a plane with symmetrical wings