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Engine basics => Engine set up tips => Topic started by: Allen Eshleman on March 14, 2015, 08:12:24 PM
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I just obtained a used OS LA 40 Cl with front needle valve. What is the right fuel? Anything special I should know about setup?
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Allen, When I ran them I always used 5% or 10% Nitro and 22 % oil half/half and ran from 10x4 to 11x4 or 11x5 props depending on what was needed at the time.
Hope that this helps...
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- The LA 40 has a mixed reputation -- some say it's crap, some say it's OK. Nearly everyone agrees that the LA 46 is a much easier engine to deal with for CL
- I would suggest the same fuel Ed does. Some people have success with all synthetic, I haven't had the courage to try in my LA 46
- I would start with an APC 11.5-4, then try the APC 11-4, the APC 12.25 x 3.75 (it'll probably be too big). If you can get your hands on any Thunder Tiger 11.5x4 props don't use them -- send them to me instead. They're much too good a fit with that engine for a beginner. I'll dispose of them safely, in broken bits at the edges of my flying circle
- AFAIK, the LA 40 is just as good as the LA 46 for RC. So if you have an RC buddy, or if you fly RC, you can swap all the "control line" and "RC" parts between an RC LA 46 and your LA 40, use the LA 40 to fly an RC plane (or give it away to a deserving RC guy, or a carrier guy), and have a really nice CL stunt engine
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I run mine on 10/11/11 fuel also. Good stuff. I talked to the dudes at OS a few times about fuel recommendation, that seems to be pretty good. I've also run it on ys20/20 it works.
I usually run like a 10x4 or 10x3 prop on the LA 40. I think the 11x3 and 4 worked pretty darn good also.
I've had good luck with the 40LA, but i think the 46 is better. Not grounds to stop using the 40 by any means. Just saying, like Tim said. If someone would trade, that would be neat.
Oh, and Use the venturi for the 25 LA.
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Thanks guys for the advice. I think I'll use it. I bought it for $25.00 at a swap meet. I would guess that it's equal to or better than the FP 40. Sounds like I need to get it a venturi insert.
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How big is the venturi now?
A really helpful hint that I got from a local flyer is to cut a bunch of little squares from some pantyhose (ask a female acquaintance if she has any used pantyhose she'll give you: that should go over well), and put them on the intake. The more you pile up, the more that you effectively narrow the venturi. Not only do you tune the engine's power level this way, but you keep the air going in nice and clean.
You can hold the stuff on with a rubber band, but it'll turn to goo in a few months -- I picked up a few O-rings of the right size at the local hardware store: they seem to last forever.
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I think I can get some panty hose from my wife. I also have venturi insert made at Lee Machining for an FP 40. This seems to have a stock Control Line NVA.
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Cool, the venturis are interchangeable between 20,25,35,40 fp to 25, 40, and 46 LA engines.
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The thing to beware of is too much prop load on the .40LA. Also, too restrictive a muffler. The TT Cyclone 11-4.5 would be the biggest I'd try. My guess it it'll work very well, because I've seen it work nicely on a .40LA. The APC 11-4...maybe, and the 10.5 x 4.5 is also worth a shot. Use muffler pressure. Most everything works well with a .272" bore venturi with a .156" spraybar through. Apparently, some .40LA's had boost ports, and some did not. The ones without should be easier to deal with. You could block the boost port easily enough, with JB Weld or a fitted block of soft balsa.
Personally, I didn't like the stock rear NV setup on my .25LA. I'd choke it and get fuel into the engine, but it would run out of the hose and would quit running before it drew fuel back up to the venturi. I'm sure it'd work fine with an "electric finger", tho. I've also seen some frustration with the plastic backplates, and I'd rather not deal with that...but they can also work ok, until they don't. D>K Steve
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How big of a tank? What tank, to get a sufficiently long run? This will be put on a Banshee with the nose shortened by 1 1/2 inches and the wing moved forward one inch. It will need to be a short and deep.
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I would expect the Hayes 4 oz standard clunk tank would work well. Most plastic tanks hold at least the nominal amount, or more. Drill out the optional spigot and plumb the muffler pressure to the lower of the two spigots. VERY nice tanks.
If you need a wee bit more run time, a little Coleman fuel added to your glow fuel will get it. No more than 6 oz per gallon, it's said to improve starting, too. D>K Steve
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DuBro or Sulivan tanks if you can't get a Hayes -- but the Hayes is superior.
If you don't have room for the tank on the engine side, put it on the opposite side of the fuse. You'll be staring at it as you fly, but they feed well that way and there's plenty of room.