I have a few LA 40s that are either nearly new or new and I am considering putting them to use.

Have you got a success story using one?

What was the plane?
What prop, venturi, needle valve assembly, muffler and fuel do you recommend?

What RPM should I be looking for with what prop?

Thanks for any advice

            I flew a Oriental ARF with the LA .40 for quite some time using the APC 10.5x4.5. It was a very good running engine and dead reliable. Several people were surprised to see that it was a LA .40. I started out with a ABN FP.40 and just had horrible results. The FP would take off and run beautifully and within 5-6 laps, it would take off like a bullet. I changed venturi's, tanks, etc. I screwed with that POS for over a month.  I put the LA .40 in it and never looked back. I used a Randy Smith tongue muffler with the holes opened up to the next fractional drill size which I believe was 3/32". My tank was a ATF  4.5 Brodak Wedge running muffler pressure to the uniflow. While most don't recommend it, it was the most consistent when applied to the uniflow pipe.  The tank was new but required lots of repairing. I always wanted to do a plastic clunk in this plane.  One thing I noted was that I was using a 4.5 oz. tank I was  barely making the pattern in the cooler months while others with the LA.46 were just using 4 oz's. I never measured my venturi as it was stock due to being a LA-S version but I believe my venturi was larger than the .25 size. I still have the engine so I will look deeper into that. I own 3 of them in which 2 run identical and  the 3rd acts like that FP. Now all of my experimentation has been in the same plane with the same fuels, plugs, etc. I never checked the venturi sizes in the 3 LA .40's I own but I have always been suspicious in regards to all of them.

Thanks Brad, Kenneth and Allen

All useful stuff.

Allen - do you know what "Motor Man" did to your engine or what size of Venturi you are using?

Thanks again

I have a few LA 40s that are either nearly new or new and I am considering putting them to use.

Have you got a success story using one?

What was the plane?
What prop, venturi, needle valve assembly, muffler and fuel do you recommend?

What RPM should I be looking for with what prop?

Thanks for any advice

Use  the engine  with a  .255 venturi and  stock OS 20 needle,  or  PA Needle  and  .281 venturi
Head as is or  1   one   extra gasket, I recommend  stock  as it comes  first
11 x 4.5  TT Cyclone prop
use  22 percent oil fuel  mostly synthetic
lock tight rear plate or replace it with metal on
Merlin  2004 plug, OS 8   or   Sig RC Long
The above is an excellent proven setup

Randy

Pete Ferguson had an ARF Cardinal with a .40LA. With the stock muffler, it was nose heavy, so we put a Randy Aero CNC Tube muffler on it. It didn't like whatever prop he had on it, so we put a TT Cyclone 11 x 4.5 on. Probably PM 10-22 and Thunderbolt idle bar plug. These few changes fixed it right up.  Steve

Bump, I also use the thunderbolt idle bar plugs with powermaster 10/22 fuel.