I've been researching the types of engines out there and I can't find any good answers on the matter; what is the difference between LA, AX, FX, ringed etc.?

The LA series is more of an entry level engine that has bushings instead of bearings for the crankshaft, fairly mild porting, etc. They do work very well for trainers and a lot of sport planes though and they are economical.

The AX series is more of a sport/performance engine with ball bearings, more aggressive porting, larger carburetors and other features. They produce more power given similar displacement than the LA series.

The FX was basically the forerunner to the AX series and served a similar place in the market.

Ringed engines use a metal piston ring just like most other small engines, cars, and other stuff. Non-ringed engines use very tight machining tolerances and special plating/coatings to create the piston seal. Most, but not all, 2-stroke RC engines are non-ringed while most 4-strokes are ringed.

The LA engines also use more plastic parts than the AX, for example the crank cover and fuel nipples. Also the 65 LA has 4 philips head screws where the 61 AX has 6 allen screws. Even if you are not flying them hard the AX's are just better built engines.

The LA series engines use bronze bushings rather than ball bearings (like the AX or FX series) to support the crankshaft. This makes the LA series engines better suited for applications like float flying where the engine might get wet regularly.

The LA series engines are also lighter weight than AX or FX series of similar displacement. The .46 LA engine weighs in around 13 ounces or so with muffler, where a .46 AX is 17.2 ounces. An LA series engine can be a better choice for airframes that balance better with a lighter engine on the nose.

The LA series of engines also feature an air bleed carburetor rather than a twin needle carburetor like those found on the AX/FX series engines. Air bleed carburetors tend to be less finicky and more user friendly than most twin needle carburetors. They don't need to be adjusted all the time as weather conditions such as temperature and humidity vary over the course of a flying season. Air bleed carburetors can be dialed in at the beginning of the season and only require the occasional adjustment.

Only top engine manufactures such as O.S. Max, Thunder Tiger, Enya, and K&B still make plain bearing engines with air bleed carburetors. They are user friendly, reliable, and well suited for many RC flying applications.

And to clarify:

LA "fairly mild porting, etc. " = FAR Less power than the AX series of engines of the same size.


As someone here once said....

"The LA .46 is the BEST .32 engine I've every flown!"

And just for clarity - LA, FX and AX are all OS Engine product lines. Other manufacturers have their own mind-numbing naming convention (just kidding).

[link=http://www.osengines.com/engines/airplane.html] OS-Engines Airplane Engines[/link]

Check the links at the bottom for parts lists and manuals if you're so inclined. OS also had a "model / engine" recommendation page where you can look up some manufacturer's planes and see what OS suggests as an appropriate "economy" engine and what they consider "modeler's choice". Gives you a chance to stand back and see how things align.

When you get to the point where you are matching an engine to and a plane - open another thread and ask for opinions. Gawd forbid, this being such a modest group 'an all you may have to "plead" for replies.

Inoticed that you're at about 2500 feet. Just know that these little beggers loose power at elevation. I'm at 5500' and am down maybe 25%. I'm very cautious when someone rants and raves about a certain engine / plane combo and they fly at sea level. We typically up-size (sometimes over the top) to compenstate. Local gurus can be very helpful.

Good luck.

Btw, Ihave a spreadsheet (sourced from a database)that includes 12 or 13 manufacturer offerings, links to sales and technical sites, weights and dimensions and to some degree "technical profile"that includes piston / cylinder sealing (ringed, ABC, etc.). If you are interested PMme.

According to OS:
46LA = 1.2 H.P. @ 16,000
46ABL = 1.65 hp @ 16,000

That's a 37% increase in power!

Yup and there is a slight increase going to the AX series as well.

All too often here newbies seem to believe that the LA series are similiar to other ABL engines in terms of power.


I installed an OS .46 LA engine in a light Modeltech .32 Extra 300, and the plane could use a bit more power!

I believe the GMS .32 is rated at 1.2 HP, and it's performance and use in smaller racing & combat planes seems to bear this out.

The O.S. Max .65 LA actually out-turns the .61 FX on a number of different propellers.

I shot a video of my buddy Fred flying his GP Combat Corsair with a .25 LA on it, and it's no slouch either:

[youtube]http://www.youtube.com/watch?v=MxWBU5BXSPc[/youtube]

The .40 LA was definitely no screamer, and the .46 LA seems to be an average performer, but some of the other LA series 2-strokes can definitely pour on the power.