Which engine?

[Jere L]

I'm just beginning to build an Eagle 2 by Carl Goldberg models, and was wondering which engine I should go with.

The trainer calls for a .40 engine, and I have an opportunity to get one of 2 O.S. Max engines at a great price. The problem is, I'm not sure which I should go with.

The first one is the .40 LA series which I understand is reliable, and pretty quiet, but a bit on the low end of the .40 power scale.

The next one is the .40 FX, which I don't have any real information about. But costs about $20.00 more than the LA.

They both come with mufflers, and I've been told that either one of them would be good engines to go with.

As I don't have any great knowledge of glow engines, I'm at a bit of an impass, so any opinions you have would be appreciated.

[Dave Robelen]

Hi Jere,
I have had some experience with both engines. The .40LA is one of the most "user-friendly" glow engines I have operated in a long time. Yes, the power is lower than the FX model, but unless you are planning on serious aerobatics that should not be an issue. .40 engines with the horsepower of the FX model were not even anticipated when the Eagle II kit was designed. With the LA version you would be able to rOG from short grass, loop, roll and genarally toss the Eagle around. All of this assumes that you will use fairly standard weight equipment with servos similar to the Futaba S-148, and that you will not empty the glue bottle on every joint;)
Regards, Dave Robelen

[Jere L]

Well thanks for the response. I have also heard that the LA engine was user friendly, so its nice to have that response validated by someone else.

I've also heard that it has good range on the throttle, but that it can be a bit of a bear to start by hand. Which shouldn't be a problem because I will be using a starter motor.

As for my building skills, I'm not exactly using a WHOLE bottle of glue each joint, only half of one :D. And my equipment is all Futaba with standard servos, battery and reciever so weight won't be a problem.

I'd still like people's thoughts on the FX engine though, like what the differences in construction between the two are, and what if any advantages there is from one to another.

Clear skies.

[Dave Robelen]

Hi Jere,
The principal difference between the two engines is the top end RPM they are designed for. The FX has ball bearings, different porting, higher compression, and a generally more rugged construction. For applications that involve higher flight speeds and smaller props the FX style has the edge. In exchange the tuning is a bit more touchy and the fuel consumption is considerably greater. If you were looking for a powerplant for serious aerobatics, that would be the way to go. Both of the engines have similar life expectancies. Beyond this kind of description, it is difficult to get into detail.
Regards, Dave Robelen

[BrokenChild]

I would say that if I were in your possistion I would get a BB.46 engine to put in this plane. A 40 will pull it fine, but with a BB.46 and an 11-5 or an 11-6 prop you would have more pulling power and more speed (not that you would want to fly this set up at full stick!) Even an 11-4 prop would be nice for this set up, it would pull more like a 4 stroke, more power for steep climbing, and with an 11-4 on a BB.46 in this plane, it would pull better than a 10-6 on an average .40...the one I flew had a K&B .45 sporster on it and its around the power of an average bushing 40, thats why I suggest more motor. I just look forward on things like this... The engine will last longer than the airplane in most cases, so then you could move up to a sport plane the same size, and not be lacking any power...

Hope I helped

brokenhawk