Hello,
I'm a neophyte-retread and brought home my first kit in over 20 years, a Sig Twister.
After perusing my engine arsenal, I have the following choices:
- OS .30 max (bought used, I've never run it)
-OS .40 max (converted from R/C and haven't run it)
-a fistful of Fox .35s (burp)

I wouldn't necessarily be against buying a new engine, and have been looking at the B-40.
 However, though I know they're FANTASTIC engines, I can't get past the look of the new OS LA engines (blue?!  Good lord...) so I don't think they're an option.  I would prefer to use what I have unless there is a compelling not to.

Thanks for any and all suggestions.

Semper Fi,
Danan

Frank,
Good point on the muffler.  I keep forgetting that they are more or less mandatory these days.  None of them have mufflers.  I'll try Tower..

Does a .30 or .40 OS max have any redeeming qualities for stunt or would I have better luck with the venerable Fox?
Thanks again,
Danan

If it were me, none of the above.. If the 40 is an FP and not reworked you might get it to work but the odds are against it. Everything else is vibration looking for an airplane to shake problems in.

Get yourself the Brodak 40 and be flying instead of messing with engine run problems.

I've flown a modified (the Fancher version) of the Twister for a few years with an FP 25.  I'm currently in the process of mounting a 40 on it.  For lessor skilled flyers (like myself) I think the extra power is wise.

I just put a Brodak 40 on my son's Primary Force ARF after an unsatisfactory experience with the highly touted FP 20.  Just didn't have enough umph.  First impressions are very high.  Changing the stock tank to a uniflow arrangement cuz the B40 was going lean 1/3 of the way through the flight.

The LA series of engines are actually quite good, inexpensive and readily available.  I'm flying a Top Flite Tutor II ARF with the LA 46 and very, very happy with that.

I also don't like the blue color but you can order the R/C version in natural aluminum finish then put a C/L venturi and NVA on it.  I have the LA 40 slated for the above Twister.  Hope to fly it tonight or tomorrow.

Both OS engines are regular old Max's; the ones that predate the FPs.  I have had some agonizing moments with engine runs/fuel tanks and appreciate the suggestion that I buy a B-40. 

Danan;

If your Max 40 is the older Max-H 40 (ball bearing raced), then you have an engine well suited for the Twister.  My only suggestion is to replace the front doublers with 1/8" five ply plywood rather that the lightply that Sig sends with the kit.  It will definitely make the front end stiffer and less prone to vibration.

The Twister will also fly with the Max-S 30, but you will have to use a prop similar to a 10-5 and run it on a wet two.  Line length should be 58' to 60' when using the .30.

V/r

Bob Kruger