reworked LA46

Somebody told me theres a artical in Stunt News on reworking a LA46, but I can't find it. Could somebody please tell me what page?

Mark: I haven't received the latest Stunt News yet, and I don't recall seeing that article in any previous issues.

My question is: Why would anyone want to rework an LA 46? These motors are ready to go as they are. The only change I make to the LA 46 is to use a tube muffler (or the old 40 FP CL muffler drilled out) in place of the stock muffler. I use the APC 12.25 x 3.75 CL Stunt prop (that's how it is listed in the APC catalog) cut down to 11.75.

I flew the Imitation with this setup in our contest this weekend and had no problem hanging with the full fuselage piped and 4S ships. The motor ran perfect every time.

>Somebody told me theres a artical in Stunt News on reworking
>a LA46, but I can't find it. Could somebody please tell me
>what page?

Stunt News, Sep/Oct 2003, page 74

Title: ENGINE TEST: OS LA46S

by Derek Pickard

Interesting stuff. I always enjoy reading what ever Derek has to say.

Cheers,

>Interesting stuff. I always enjoy reading what ever Derek
>has to say.
>
>Cheers,
>
>Warren W

Yeah, but some of it you may just want to keep to yourself. I certainly would not grind on a motor--as Derek suggests in the mentioned article--based upon his advice alone. Especially when the unit in question is a known quantity, hand-jive "rework" is so risky.

He's out to lunch on this motor. Sorry.

LAST EDITED ON Sep-01-03 AT 03:16 PM (CDT)
 
What Steve Moon said!

LAST EDITED ON Sep-01-03 AT 10:50 PM (CDT)
 
I thought it was the July/Aug issue, no wonder I coundn't find it. I'm with you guys, I can't see how it could be improved, so it seemed interesting to me what was written.

Its interesting that the prop is now listed as a CL stunt, I believe it was once listed as a R/C funfly.

Your right Mark, that prop is very popular for the RC fun fly crowd. They sell them like crazy at our LHS. Maybe they list them both ways in the catalog. I was using a dealer catalog in the past when I worked at a hobby shop, so maybe there is some difference; oh well.

THAT was an LA46? Awesome!!

Just thought I would let you all know that OS has changed the Crankshaft and piston on the LA 46. The crankshaft is heavier for better throttle response. Problem is it shakes more. The piston is machined now insted of cast, which is better. Also by redirecting the ports you can increase the fuel econony by about 15%. In doing so you increase the torque from 57.0 in oz to 59.2 in oz and the HP from 0.666 to 0.706 (APC 11.5X4 prop).

I do agree it still a great engine out of the box.

Larry Foster

Ron B.
F4Fguy

Go Larry!!:Exactly what I,ve been"preaching"all along!
Thanks for making the point and backing it up with numbers.

>Just thought I would let you all know that OS has changed
>the Crankshaft and piston on the LA 46. The crankshaft is
>heavier for better throttle response. Problem is it shakes
>more. (snip)

Heavier for better throttle response!??? Machining the piston I will buy, but making the crankshaft heavier???? OS has been making the crankshaft heavier with each evolution of the FP, which really meant one or two less machining operations, until they went to the cast crank that went into the LA. But now they made even that one heavier? I will also buy the shaking, since there is less counter balance built in, but I don't understand how this would in any way be related to better throttle response. The weight of the crankshaft makes a very poor flywheel, but any flywheel effect can only hurt throttle response as I see it. (Of course, these are the same people who claimed that skipping the operation of cutting the boost port in the case increases high end rpm when, in fact, it decreases it. Good for us, bad for RC which is its primary target.)

LAST EDITED ON Sep-06-03 AT 11:33 PM (CDT)
 
>
>Heavier for better throttle response!??? Machining the
>piston I will buy, but making the crankshaft heavier???? OS
>has been making the crankshaft heavier with each evolution
>of the FP, which really meant one or two less machining
>operations, until they went to the cast crank that went into
>the LA. But now they made even that one heavier? I will
>also buy the shaking, since there is less counter balance
>built in, but I don't understand how this would in any way
>be related to better throttle response. The weight of the
>crankshaft makes a very poor flywheel, but any flywheel
>effect can only hurt throttle response as I see it. (Of
>course, these are the same people who claimed that skipping
>the operation of cutting the boost port in the case
>increases high end rpm when, in fact, it decreases it. Good
>for us, bad for RC which is its primary target.)

Leonard, I e-mailed OS and that's the answer I got back, took 2 weeks. There is more weight at the piston pin now. The new crankshaft is 8 grams heavier. I would say your 100% right about the machining process. There is an upside to the new crank. It's more work to get it to balance but it's smoother when you’re done. The attached file is ACAD14. It shows the shape of the new crankshaft.
Larry

If you're worried about total weight, you can cut alot from the outside of the crankcase. It has no transfer for the boost port but still has the metal on the outside for it. I trimmed down my LA .40, I call it the LA lite.

Giffy
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I Fly