DLE 20 - how much thrust angle?
 

I'm installing a DLE 20 in a trainer that was formerly glow powered. The trainer's firewall does not appear to have thrust angles built in and the manual for the DLE 20 does not mention thrust angle at all.


So I have a few questions...

1. Do I need to consider thrust angle?
2. If so, in what direction and how much?
3. What's the best way to accomplish this?

If I do need to accommodate thrust angles I'd like to know before I mount the engine so that I can position the mounting holes accordingly.




Cheers,


John.

if it flew fine without thrust angle with glow itll be fine without it with gas

I agree with above post.

If any, you may need right and down thrust most likely, for which some washers at the top and/or left spacers will suffice

However, first flights will tell you what is needed for fine tuning; 0 - 0 degrees will be absolutely fine for first flights.

Interesting... thanks for your thoughts.

Before suggesting where it should be I would be inclined to ask where the original placement was. I would then mimic the original installation but with an additional degree of right thrust. The DLE has a touch more rotational mass and a little more prop pitch.

Grosbeak, there is another thread on here that shows a product called something like thrust shims. Three plates come in the pack 1, 2, and 3 degree plates. Maybe they could work for you. If one isn't enough, you can try another since they are the same size, so swapping them out would be easy.

LOL.....it's called Dave Brown Motor Mount Shims....... Right now, it is 3 threads below this one.

Like most people I start out with zero/zero then fly the plane. At the field I just use washers to add the thrust if needed. When I get home I then make up a beveled thrust plate from ply and it goes behind the motor mount. Each plane is different so it's just part of how you trim. Most planes end up with a bit of right thrust and some want some down? You never really know until you fly the plane. Some kits and ARFs put the thrust they figure is best after a lot of flight testing and it's often very close.

More good info. Thank you.

Alot of it depends on the plane, my last one a Tiger 60 had 2 deg. right and down with full symmetrical wing, the 1/4 scale Spacewalker I'm building now has none and it has a semi symmetrical wing so it has something to do with the airframe. Fly it and adjust as nessessary.

Leroy

Leroy, that's the plan I've decided on. Fly it with no angles, add as needed. I am going to scratch build a cowl for this airplane but I'll wait until after the thrust angles are determined because of the changes they may make to the angle of the engine and the forward position.

:eek:Thats a good idea grosbeck because one thin washer will move the center at prop over more than most think. Heck 2deg. will change it 3/16 to 1/4" from center at fire wall to the prop center, same for down thrust.:eek:

Leroy

I forgot to mention that many fire walls are square to thrust line and If you have the manual or plans it will tell you to cock the engine on the mount to get the angles if needed on that plane. If you don't have them and know what your plane is you might ask that question and someone may have that info for you.

Leroy