os engine

[John Desrosiers]

Im thinking of bolting an os 20 on a sig akromaster. Would it be too much power?

[Tim Wescott]

Which one?  Was there a 20S? 

The FP 20 is definitely too much -- I have one on a 34 ounce Ringmaster, which it flies with authority on 60 foot lines.  I won two trophies with that Ringmaster (in Sportsman Profile and Classic) at the Fall Follies in Salem Oregon this October.

An Acromaster with that engine probably wouldn't shed parts if it was well built, but it'd have way too much engine for stunt.

[John Desrosiers]

Yes it is an fp 20 with a muffler

[Duke.Johnson]

I use the Fox .15's no mufflers and my sons use the OS .15FP's and LA's. No mufflers.  You want light.  We have had a few Akromasters now.  Great plane.

[Tim Wescott]

John, the FP 20 is perfect for a Ringmaster -- even a porky one like mine.  It's good on a Sig Skyray as long as its not too heavy (toward the end of its life, my Skyray was more epoxy than balsa and preferred an LA-25 in the nose, but it flew OK on an FP 20).  These are planes in the 420-450 square inch range -- not 250 like an Akromaster.

[John Desrosiers]

Would the Brodak cosmic wind be ok. Im thinking of buying one.

[Tim Wescott]

What do you want to do with it?

If the answer is "have fun", then yes, it looks like a good choice.  It won't be the best stunter in the world -- the tail's too short.

If the answer is "buckle down and learn stunt", then based on Brett Buck's extensive reporting, and my own meager experience, I think your best bet would be a Sig Skyray with the wing ribs done in 3/32" balsa instead of the ply supplied with the kit and otherwise bone stock.  Buy one kit, then build one or two extra planes from the plans.  Then start burning fuel.

[Duke.Johnson]

I think the Cosmic Wind designed for an old 35 (Fox).  Mine had an OS .25FP and flew great (for fun flies).

[Dave_Trible]

John if you already have the Acromaster and need an engine I have a few Enya .19s here and will send you one.  They aren't too much for a Flying Clown which is smaller.  Just let me know.

[John Desrosiers]

MMMMM. Ok let me know how much you want for it.

[Russell Shaffer]

If the Akromaster isn't built yet, think real hard about not cutting down the wing spars.  You have to make a couple of extra ribs, but a longer wing will fly better. 

[Dave_Trible]

MMMMM. Ok let me know how much you want for it.

Just PM me your address and it will magically appear at your door soon.

Dave

[John Desrosiers]

Dave, I sent you my address on a pm. hope you got it.

[Dave_Trible]

Dave, I sent you my address on a pm. hope you got it.

Got it.

[Ara Dedekian]

John

    I've built three Sig Akromasters. Engines were a McCoy 19 Redhead, OS 20 four cycle, Veco 19 ball bearing, and the last one, shown below, is powered with a Fox 19 plain bearing which still show up at RC auctions and e-bay. ( I have many of them!) I lengthened the rear fuselage by 2", as Russell suggested,stretched the wing to 39", covered the entire plane (markings included) in Micafilm for light weight and stiffness, and fly without a muffler. Next project is to make a tongue muffler for it.

    When the Fox 19 is working properly, it's a terrific combo. 27% lube, 10% nitro. Some years back at a stunt contest at Westover Air Force Base in Massachusettsthe winds were blowing 20-30 mph and out of a field of 13 in intermediate all but Guerry Byers and myself dropped out. The Akromaster handeled it like it was a 5mph breeze and I completed my version of the pattern. (A loop with a wiggle in place of the Hourglass, etc.)

Ara

[Ara Dedekian]

Here's the other side

Ara

[John Desrosiers]

Thank you all for your help. I,ll make the wing longer and use Daves engine.

[Russell Shaffer]

Another good tip is to use brackets and bolt the landing gear on like in Ara's picture.  The "shock absorbing" kit gear with the rubber band will fold back and break the bottom wing spar in a hard landing.  You will have fun with this - it is a great little airplane.