Hi guys, I am about finished with my first kit, a Sig LT 40. I need some advice on engine choices. My LHS suggested that I put in a .46. I looked at tower hobbies and such sites as those and I am a little confused as to which model to get. I know it should be ball bearings for the crank shaft.

How about ABC vs ringed. And what does FX, LA, FS stand for. I want an engine that I don't have to modify the fuse to get to the needle valve.

I also want this engine to be able to up grade to the next step i.e low wing sport type. How big should I go. Any suggestions would be helpful. I would like to by from my LHS as it is a mom pop establishment and I support the little guys.

Almost any 46 engine would be fine. There are several to choose from like OS 46FX, Thunder Tiger Pro 46, Magnum XL 46, etc. All of the above mentioned are good engines. It just depends on how muchyou want to spend. Personally I would go for the Thunder tiger because it is about $30.00 less than an OS. The choice is yours. You really can't go wrong.


I would however stay away from the LA line of engines. They just don't seem to have alot of power for their size.

firefighter56,

I can't really give much advive on the Thinder Tigers or Magnums, but I have 4 OS engines that I purchased used from my instructor and they are great. I do know that care for them after flight and the proper break-in should be a must for any type of engine to keep it performing up to par. Good luck with the Sig and have fun

Just stay away from the OS 46LA, it has no power and grow tired of it quickly

An OS 46fx or Thunder Tiger 46Pro would serve you well for both years and models to come. They're both ABC-type ball-bearing engines that have a reputation for user-friendliness and good power. I've got a 46fx that is a sweetheart of an engine, and a couple of Thunder Tigers that I've been nothing but pleased with. It's hard to go wrong with either of them. The main difference is cost and needle valve location. The Thunder Tiger is a lot less expensive, and the OS has the needle vavle further from the prop. What that means is that when you go to make adjustments to the engine your fingers won't have to come as close to the spinning prop. If you're mindful of what you're doing it won't matter much.

ABC and ringed are the two methods engines can use to generate compression in the cyclinder. Aluminum, Brass, Chrome (ABC) uses the different thermodynamic qualities of the metals to achieve compression through piston fit. Ringed engines use a compression ring around the piston. For all intents and purposes you won't notice much difference between the two anymore, and the majority of sport engines are ABC-type.

The other big difference is ball-bearing vs. bushing supported crank shafts. BB engines have noticeably higher performance, but a bit higher weight. OS's LA series is a bushing engine, as is Thunder Tiger's GP series. They cost less, but you get considerably less performance. The other side of the coin is that these engines tend to last a long time.