How many people have a hemi head on their .46LAs?  Wondering if it would help or not.  Still looking for a wet 2 run.

BIG Bear
RNMM/AMM

  Hey Coach, We (in the Baton Rouge area) are runnung LA 46 engines withe the "squish" band opened up, or reduced.
  This reduces the compression some what and gives a softer 4-2 break.
  Years ago, before he died, Charley Melancon would do this for us, and we really liked the way it ran, since that time Curtis Shipp has been doing them for us.

  Tell him that I said to make the up like he does for me, I think that you will like them..
  We are running 10-22 fuel with Thunder Bolt idle bar plugs, and APC 12x5 props.

  Hope that this helps...

Hi Gil,

Thanks!  Are you running a "true" 4-2?  I haven't tried that with the .46LA.

I'll get hold of Curtis, already have several of his back plates!

Bill "Coach" Little
AKA: BIG Bear
AKA: Mongo (race team nick name, we lost a car in the ARCA race at Daytona, totalled)

A late reply to Mr. Little's question about LA hemi heads.

I have two LA engines that had a clear pinging problem. So I was advised to have the heads modified, by indeed cleaning up the squish band(hemi head shape). And it helped! Only thing is I am still looking for the optimal prop.
I have used the APC 12x4 , APC 12,25x3,75 and Zinger 11x5, but I have the impression that I am over loading the engine?

However, the pinging is gone.
I use 5% nitro and 20% castor oil(1:4).

A late reply to Mr. Little's question about LA hemi heads.

I have two LA engines that had a clear pinging problem. So I was advised to have the heads modified, by indeed cleaning up the squish band(hemi head shape). And it helped! Only thing is I am still looking for the optimal prop.
I have used the APC 12x4 , APC 12,25x3,75 and Zinger 11x5, but I have the impression that I am over loading the engine?

However, the pinging is gone.
I use 5% nitro and 20% castor oil(1:4).

I've had very good luck with the APC 11.5 X 4 for most airplanes...Seems to load the engine just right at about 9500 RPM ground launch speed.
I would definitely reccommend fuel with 22% oil but half castor and half Klotz.  Works very well.

I have tried hemi heads and increased squish band areas and can see no difference between that and simply adding a shim under the stock head.  In fact some changes to the squish band area give erratic results and greater fuel consumption with a loss in power.

Randy Cuberly

Back when I ran an LA-46 in my yellow Time Machine 50, it was stock head, .285 venturi with a ST NVA, APC 12.25x3.75 cut down to 11.75" diameter.  On Powermaster 10/18 it tended to run a wet two stroke, on 5/18 it ran a very crisp 4-2-4 run.  So, my setup at least was very sensitive to nitro in terms of what run you had.  I tested a hemi head for the LA made by a sekrit engine shop down in Florida, but did not observe a massive change in engine run.

The biggest problem by far with LA based engine research was that some of the engines "went away" in as little as 300 flights.  Often insp[ection of the engine would reveal not a peeled liner, but a liner that had areas where the nickel was so thin that you could see through it down to the brass.  Liner scuffs or wear would change power output or run quality to a degree that confused any other experiments.

I forgot plug, which may or may not make a huge difference.  I ran the Sig 003 in my LAs and FPs.

I have now gained some experience in flying my Stunt Rocket with my modified OS 46LA. Using an Enya 3 plug and a Zinger Wood 11x5(unmodified!), I have a perfect 4-2-4. Flying level in wind the engine switches nicely, and after  five loops (OTS) it will come back to fourstroke as well. So I am a happy person at present . And it starts on one flick!

I am glade you like the LA 46 and how it starts and runs and after a while as it gets more wear it will be harder to start-especialy when it is hot but the good news is it has a good crankshaft bearing and it can be made to run brand new with new piston and sleave and maybe new connecting rod. In any case it is a good stunt engine right out of the box and it would be a real shame if OS quit making them so I think we all should let OS know how well you like this engine and so far know chinese copy on the market. I wish it was a true ABC with a chromed sleeve instead of a nickle one as it would be a longer lasting engine and if they did it this way it would be OK to raise the price to pay for the change.

I'm sure OS is noticing the sales numbers for the C/L 46LA !  A cardinal rule of business:  if your product is selling, just keep on making it!  (Yearly modifications are for the auto industry).

F.C.

Actually, the rule for OS (with C/L stunt engines anyway) is to stop making them just when everybody is using them. See OS 35S, OS 40 VF, 46 VF, 35 and 40 and 20 FP, etc.