Has anyone successfully shaved superfluous metal from the cases of some of the powerful but heavy IC's.  I look at the ST .51, the entire OS AX series, possibly the old Veco/K&B/Mecoa .61's, the teardrop rear of the Evo .60 case and head, and I can't help think that their cases are needlessly "beefy."  Not a machinist, my thoughts include files, rasps, and sanding discs!  I know, I know- "Horrors-I can't watch"....but since we're not opperating in screaming-lean R/C mode, I doubt that all the case strength or heat disippation is required for our application.

You can machine for hours, and expect  grams NOT ounces, I don't believe anyone can take 2 ounces off of an LA 46 and keep all parts and make the engine still work... nOw you can unbolt the muffler and do that,
I have machined on many engines for hours to lighten them, 1/2 ounce is a ton of metal shavings, and about what you can expect, unless you start with a very very beefy heavy motor

Randy

It's possible to get significant weight off an engine.  Typical F2D engine weighs about 130 gr.  A Magnum 15 or TT 15 weigh around 160 gr.  similarly equipped.  The main savings is in the case.  The lighter engine has a case with ~ 0.040 thick walls.  The TT 15 has ~ 0.090 walls plus a small amount of decoration.

The problem with making that kind of difference on an LA 45 is thinning the case overall by 40% or so, without cutting through the walls.  The only well-controlled way to do it would be with CNC machining.  That would require making a very accurate internal model of the engine to use as a machining guide.  Might be easier and cheaper to just design and cast your own case.

   That's not the only problem. Changing the thermal mass and other thermal characteristics matters, too. My help or hurt, but not likely to stay the same.

    Brett

  That's not the only problem. Changing the thermal mass and other thermal characteristics matters, too. My help or hurt, but not likely to stay the same.

    Brett

UH HUH  Exactly, that is also a large problem. Removing material in significant quantities , will almost NEVER ,result in a stunt engine running better.

And I can tell you I replaced many dozens heads that people ground the fins off of, trying to make the motor lighter, Then the motor would not run right, or cycle correctly for stunt.

Randy

Possibly grinding off the beam mounts and simply using the back plate bolts radial style and substituting the steel prop nut for a combined washer and alloy sleeve nut may help a little.

Grasping at straws here but are ceramic bearings any lighter than all steel ones?

  Yeah, Randy's right, I shouldn't used the term "ounces" so loosely, it isn't that much.
  I apologize ...

Hi Nothing to apologize for,
 You would not believe how large a pile ,an ounce of shavings from aluminum are coming off a lathe. it take a lot to remove ounces....

Randy

And I think John Wright shaved quite a bit off a Series 21 McCoy. LOOKED like a lot, anyway...

For those who may not remember them, the Series 21 McCoys had steel fin sleeves with Dykes ring aluminum pistons. the lower case was bulky, blocky and looked like it was made that way for appearance, not performance.

They ran well, and lasted pretty well if you took tender loving care of that (at that time, new) kind of ring. Performance was like we had wished alll the McCoys ran when they were most popular, and a bit better. But, an 8+ ounce 35 was a bit hefty.

John Wright never said how much weight he'd cut off. The bottom end on these engines had a lot of metal that could not have helped strength, or likely added much for cooling...