Seems that I read a few years ago how to make stunt engines out of the osla engines.  Could somebody fill me in and what fuel do you suggest.  Dudley Lang

If you look in the "Engine Setup Tips" forum, there is a "pinned" topic on the .46LA, and a search will show up info on the .25LA, and some on the .40LA. I don't recall seeing anything on the .15LA or .10LA, but that doesn't mean much these days! Steve

Seems that I read a few years ago how to make stunt engines out of the osla engines.  Could somebody fill me in and what fuel do you suggest.  Dudley Lang

   They are already stunt engines!!!!  The 46LA works very nicely straight out of the box, no significant modifications are needed.

    Brett

I have seen too many fly way awesome right out of the box, with minimum break-in, to consider any reworking of this motor.
Personally, I would prefer Randy's AeroTiger. But for the money, I think those LA motors are hard to beat.

Larry, Buttafucco Stunt Team

I'm running several OS 46LA engines.  Sometimes, only an extra head shim is called for to get a more consistent run.  Otherwise, they need nothing else for stunt.

Floyd

Seems that I read a few years ago how to make stunt engines out of the osla engines.  

Still trying to figure what an 'osla' engine is, but anyway ............ define what a stunt engine is, and I assume that you mean a good one and you will get as many differing opinions as there are stars in the sky.

As mentioned they are perfectly fine as stock but they can be 'improved' to taste.

Try 'Rustler' from this forum, he has massaged osla's for sale.

rustler@aero.fslife.co.uk

I think Ian has massaged the Merco engine for stunt.  Hard to imagine doing mods to the OS 46LA.

Floyd

Hi Floyd,
                he gets them done though and from memory its with his own style of hemi head, venturi and backplate.

Hopefully he chimes in here to confirm.

From his price listing -

A short, possibly inaccurate, and (if it's coming from me) hearsay-based history:

When the Schnuerle-port engines first came out they were a great puzzlement to people used to run baffle-piston engines in 2-4-2 mode.  Correspondingly great effort was expended trying to make the engines behave as expected.  (I wasn't flying stunt at this time -- I was making it through college then raising kids, which took up all my time and energy).

After a time, it was discovered that the way to run these engines is in a fast, wet two-stroke with a flat prop (I see the APC 12.5-3.75 prop recommended a lot).  When you do this you get lots of power, only when you need it, and not too much speed.

Not all schnuerle-ported screaming-fast engines make good stunt engines -- you still have to ask what works well.  The LA 46 is reputed to work well, as you can see in this thread.

What you've read is probably a leftover from the "make it work like a Fox 35" period.

Some people still seem to feel that such an engine needs to be reworked to run correctly -- I refuse to opine on that.

The reason these 46LAs work may be that it has three ports.  There is no port directly opposite the exhaust port.  The Adamissins blocked off this port on the 40fps when they came out.  I don't know the port arrangement on the 25LA. 

The reason these 46LAs work may be that it has three ports.  There is no port directly opposite the exhaust port.  The Adamissins blocked off this port on the 40fps when they came out.  I don't know the port arrangement on the 25LA. 

That is not the reason they work

Randy

Ok Randy.  I did say may work.  You are the expert.

So why do they work, or why does the LA46 work better than the LA40 or FP40.  I'm sure there are many reasons but the ports are an obvious difference.  Also there are some reports that the more recent LA25's seem to run better, anyway seems like somebody reported this somewhere on the forum.

The motors like Aero Tigers, Enya, Magnums, PA, Merlin, HP,  and many other with boost ports all can and most times do run very very well, The OS LA 46 works just as well , if not better  with the boost port cut into the sleeve, Normally the larger the same case motors with larger bore are inherently smoother..if that is the best way to say it. As far as the 40 LA  I have setup many of them that run great, and to compare you can look at the G21 40, and G21 46, they are very much like the 40 /46 LA , the big bore engine runs better. But both can be made to work well, and many times better

Randy

The 25LA setup is just a simple bypass port, very similar to a Fox 35.

   No, it isn't. It is NOTHING LIKE a Fox 35 inside. First, it has no baffled piston, its a classic schneurle loop scavenging (with two intake ports). There is no boost port, but that is just an addition to the original schneurle design. It still counts on the intake charge looping up to the top while displacing the exhaust based on the geometry. The Fox has a baffle that deflects the single intake charge up along one side of the cylinder and counting on that pushing out the exhaust.

   Secondly - everything else. Aside from having a front rotary valve like most engines after the Brown Jr. era, just about everything else in there is different. Not surprisingly the handling qualities and resulting performance is utterly different as well.

    The 25LA (or any similar current production engine) is about as utterly different from a Fox 35 as it could possibly be within the constraints of a single-cylinder glow engine. You are comparing a flathead Ford with an Indy Car engine.

   As always, people may well prefer flathead Fords to and Indy Car engine for whatever reason, but they are NOT the same.

    Brett