Hello,

I plan to make a purchase this Friday for my new LT 40 trainer.

I searched the engine forum and did not find an suitable answer for my question.

The dealer will give the following engines for these prices if I buy the entire plane package.

O.S. .46 for $64.99
Evolution .46 for $79.99

My questions is, is the evolution worth the extra money? If so, why? More power? Easier to operate?

I would greatly appreciate any recommendations or information.


Thanks,


Wings,

i cant really speak for the o.s engine but i own the evolution .46 and its a really good engine. everyone at my club loves it. evolutions first attempts at an engine fell short of even the starting line hah. but they definatly hit the nail on the head with this one. if you have access to model airplane news the new november issue has a review of the engine. hope this helps.

If you flip a coin you won't make a bad decision here. I have helped a few with the Evolution and it really is a user friendly engine. Idles like a champ and easy to start. So have the OS engines. One recently soloed flier was surprised at how easy the OS 46 FX was to run. No need for the electric started he had been using. Learning how to set and adjust an engine is part of the fun of flying.

EXCAP232

Just to clarify, is it the OS 46LA or the OS 46FX you're looking at?

I'll second the importance of that question!

O.S. .46 LA

By the way, I know FX is for more power and speed, but what exactly does FX and LA stand for? I do have the LA.

I don't know that LA and FX stand for anything in particular...probably just a way of differentiating the two lines of engines...

How the evolution and the OS46LA compare in terms of power, I'm not sure... but I have flown an LT40 with both an OS46LA and with a 46FX... the LT40 will fly on the LA, but I found that the FX was a better match for it... our field is surrounded by trees (actually make that TREEEEEEES!), so immediately after take-off you had to make an immediate climbing turn to get over the trees at the far end of the runway and continue climbing to get over the trees on the downwind side of the pattern... the LA, being weaker, made take-offs and go-arounds a little more "exciting" than was comfortable at the time. The FX made things much more comfortable.

Bear in mind, that this was relatively early in my flying... so things became "exciting" quite easily. If your field allows for more gentle climb outs from take-off, you can probably do OK with the LA...my particular combination of skill(or lack thereof) and terrain made the FX a better choice. What you might want to do is go to the field you'll be flying at and ask the instructors their opinion...

My opinion, if the evolution is roughly comparable to the OS 46FX, get the evolution.

What is the reasoning behind engines that have the same displacement but have different power? How can they have different power if they have the same displacement? Is it the internal friction that takes away from the power? How about the carb; does that change things up? Educate me.

I have read that the FX has a dual ball bearing supported crankshaft, while the LA has a bushing supported crankshaft; and that they also have different carbs...the LA has air bleed type while the FX has twin needle type. I think the FX also has a metal backplate, and the LA has a molded composite material backplate.

The FX is sturdier, more durable, and has a better carb that provides more power with easier starting than the LA.

chuck a OS46fx in it they have plent of power and then when upgrading u can put it in an aerobatic plane for a bit better performance

Chuckr53-RCU is pretty much right on with the differences between the OS FX and LA line. The big differences are that the FX line has a Ball Bearing (BB) supported crankshaft, while the LA line uses bushings. The carbs on the FX line are more advanced "two needle" design compared to the "air bleed" carb on the LAs.

As for why two engines with the same displacement have different power, thing about car engines. A racing 2 liter engine is a heck of a lot more powerful than what you find in a family sedan. The reasons are things like valve timing, compression ratios, fuel systems, etc etc etc.

Well, the exact same things affect model engines. The OS FX line of engines have carbs with larger thoats than the LA. The LA line, in fact, has some of the smallest carb throats you'll find on any engine in that class. A larger thoat means more air and fuel can get in to the engine, but it also means fuel draw is more critical. Smaller throat engines idle better and tolerate bad tank setups better, but produce less power.

The intake and exhaust timing is likely different between the FX and LA engines as well. I haven't timed them myself and I'm too lazy to go find reviews that give the numbers, but you can be sure that the FX line will have more "aggressive" timeing to get more fuel/air mixture in, and more exhaust out of the engine, giving more power, but at the expense of a harder to tune engine. The FX also has a higher compression than the LA, at least based on my experiences with the engines. Again, more power, but harder to tune.

So, why would OS bother to build the LA line? They are cheaper, and the OS FX line is rather expensive, that's one reason. The LA line is also designed to be easy to start, tune, and idle well. It does all those things quite well, it's one of the best behaved engines out there. The FX can be a bit tempermental at times if you are using the wrong glow plug or don't have it tuned right.

Back to the origional question, the Evolution engine is roughly equal to the OS FX line. BB supported crank, two needle carb, solid compression. In the air, the Evo and the FX are going to fly the same. Both the FX and the Evo produce a heck of a lot more power than the LA line. For that price difference, get the Evo, no question about it. If the choice was an FX or an Evo for the same price, flip a coin. For a beginner, I'd lean towards the Evo, for a 2nd plane, I'd lean towards the FX (again, assuming the same price)

Just as an example, the evolution in my alpha trainer with 15% fuel, no muffler baffle, and an APC 12x4 will leave the ground vertically from sitting on its tail and fly away. I grab it before it gets away because I'm a newby but it does pull.

SPEND THE EXTRA MONEY!!!!!!!

The OS 40 LA does not have bearings. The Evo does.

The OS 40 LA does not have much power. The Evo does.

The OS 40 LA does not come with a glow plug (You will have to spend about $10 more for one) The Evo comes with one.

Click on the "Magazine" tab at the top of this page, I just did a review of the Evolution Engine, and given a choice between it, or any of the OS LA series, I would buy an Evolution every time. (And I really LIKE OS Engines, but the Evo is a MUCH better deal than the LA series.)

I also vote for the Evo.......it's definitely worth the extra money over the LA. I got the chance to see one run for the first time last week.....very smooth, excellent idle, and great transition.

Go for the EVO, it's a hell of alot better the the OS LA, my evo runs over my dads 46 LA.

I'm an OS man,I have 3 46FX motors and I love them all.But I haven't tried the Evo yet I here they are good also.My FX is starts so easy all I have to do is hook up the glow starter and give the nose cone a flick with two fingers and it cranks right up.The key to any engine is to break it in right and dont abuse it.Any good motor can give you problems if not taken care of.If you chose to go with the OS stick withthe FX it may cost more but will last forever if run right.The LA will pull a trainer good but may have problems with a good second plane.Good luck and have fun![8D]

Get the Evo engine or better yet for about the same money get the Thunder Tiger Pro .46. I have run most of the engines in the .46 class and think the TT is the best for the money. I have a OS 46 FX, Magnun XL 46, Super Tiger .45, and the TT46. I like the way that the TT runs and it has the same power as the OS engine. The OS LA series engines do not make the same power as the rest of the ball bearing engines. The LA series engines run well though. I have had the 40 and a couple of 15's. I liked the way that the Evolution engines run. I have had the 40 and a friend has the 46. They start easy and are already broken in. You can install it and go fly. If it were my $ I would buy the Thunder Tiger.

Rick

$10 for a glow plug?

Ok, $5.

But you still have to drive to the LHS to get one. (In my case, that's a 2 hr drive)

I have an o.s.la40 and three evolutions, a .40, .46, and .61. There is no comparison between the evos and the o.s. la's. The evo's are much more powerfull, idle better, and are quieter. They also are all metal instead of using composites. They all start with a flip of the chicken stick. All three ran great right out of the box. I think the evo's are going to give the O.S. fx line a good run for the money also. I know a couple of O.S diehards who swear by them. But, they took a double take when they saw the evolution's run!!!

check out Sept. Model Airplane News... they have an extensive review of the Evo motor and give raving reviews... i don't have it in front of me but aparantly it's got more HP than pretty much anything in it's class. They're all broken in, pre-tuned, and once you're done training can really scream w/ a 2 blade prop.