Author Topic: New SIG banshee.... engine choice? (Read 5761 times)

Dane Martin · « **on:** March 21, 2015, 08:21:40 PM »

So I'm building a new SIG banshee... I really love that plane! Everyone saw the OS 40 FS i put on the ugly banshee. Flew fine but now that I'm a little better at flying the pattern, I'm wondering if i need more power? It's strange. I flew the pattern just fine, the banshee was the first plane i completed the pattern on. Now that I'm trying to square up my squares, it feels like I'm lacking power. My RM800+P has an os52FS. It's WAY bigger, but lighter. The square maneuvers look much better, cuz there's no sag, or stalling. So I'm wondering...
Would a banshee benefit from an OS52FS?

Bill Little · « **Reply #1 on:** March 21, 2015, 08:41:50 PM »

Hi Dane,

As you know, all the tips on the Banshee deal with shorting the nose moment to balance and that LONG nose!

I don't know if you could come close even with the shortened nose moment with the 52 four stroke! Maybe an OS .46LA would be a lot better choice. Just sayin'

BIG Bear
RNMM/AMM

Tim Wescott · « **Reply #2 on:** March 21, 2015, 10:15:00 PM »

You cannot go wrong with a 46 LA
The Banshee has a fairly low aspect ratio wing, which translates to an airplane that will generate a lot of drag in the square corners if you bang them hard. An LA 46, or (probably) a Tower 40 is plenty of motor
I dunno nuthin' about them four strokes; if they truly go by the "less power than a 2-stroke" rule then a 40FS may not be adequate -- so if you're going to stick with four-bangers, do whatever a four-banger expert tells you to do
Shortening the nose is probably a Really Good Idea
If you're not too far along in the assembly, a really good way to shorten the nose in a Banshee is to move the wing forward in the fuselage. That shortens the nose at the same time that it gives you some Really Helpful tail volume. You may even want to add some area to the elevator while you're at it (basically Fancherizing the thing)

Bob Reeves · « **Reply #3 on:** March 22, 2015, 08:16:52 AM »

Ran properly the OS 40 FS will have as much if not more power than an LA 46, I know first hand a Saito 40 will fly anything an LA 46 will fly. The old days of 4 strokes being down in power verses the same displacement two stroke are long gone. The only reason you don't see many 4 strokes is because everyone started moving to electric about the same time we figured out how to really run a 4 stroke. If the electric movement hadn't taken off like it did I am positive you would see allot more 4 strokes being ran.

For sure move the wing forward, just cut out a rectangular section of the fuselage around the wing cutout. Elongate the cutout forward by however much you move the wing. Glue the section you cut out back into the fuselage at the new location and place the smaller section you cut out to move it forward at the back. I would move it forward far enough to just be able to mount a 4 ounce slant front Sullivan tank between the wing and rear of the engine.

This shows the nose of my Shoestring which is really a Brodak P-40. Little larger than a Banshee but the same idea.

Brett Buck · « **Reply #4 on:** March 22, 2015, 12:39:21 PM »

Quote from: Tim Wescott on March 21, 2015, 10:15:00 PM

I dunno nuthin' about them four strokes; if they truly go by the "less power than a 2-stroke" rule then a 40FS may not be adequate -- so if you're going to stick with four-bangers, do whatever a four-banger expert tells you to do

A 40 4-stroke is plenty of power for a Banshee. The "60% rule" is about right (or optimistic) if you look at the peak HP, but you can't use anything like the full power of a 46LA in a stunt plane, unless you can find a prop with 2" of pitch. You *can* use the full power of a 40 4-stroke, there's no real issue with flogging it within an inch of its life, since it's not going to over rev or get wild.

You could probably do OK with a 26 Surpass. It would still be better than a Fox/McCoy 35, but you definitely will have to flog it.

The only real question is how to run it, either the conventional 4.5" pitch revs (which liberates more power) or the Igor Panckenko/Bob Reeves way (which generates much less power but has more responsiveness, and is certainly much easier on the engine).

I would expect this combination to be a very good performer, if the wing is moved forward sufficiently.

Brett

Dane Martin · « **Reply #5 on:** March 22, 2015, 05:47:51 PM »

I would think the 40fs has to be enough power! People fly banshee's on a fox 35. My opinion is the 40fs is more power than that. My opinion, I'm a fox fan. Just saying.
Maybe I'm doing something else wrong. It's enough power to do the pattern, but the same banshee on a .40 la was noticeably more power.

So people fly these things on Fox 35's.... Does that mean an os25la would fly it? I've never tried it, but i would think the planes too big.

Bill Little · « **Reply #6 on:** March 22, 2015, 07:44:03 PM »

Hi Dane,

I have seen a stock Nobler ARF do extremely well in Classic (top 3) using a bone stock LA .25. And it was pretty turbulent!

I would go with a stock .46LA, myself

(and move the wing forward in the fuselage!)

BIG Bear
RNMM/AMM

Dane Martin · « **Reply #7 on:** March 22, 2015, 08:35:34 PM »

Excellent point Bill !
I too have an arf nobler with a 25la and it flys like a champ.
I talked to Bob Z on the phone today. I think we maybe isolated a problem with my 40FS as opposed to it not being enough. It's just a problem with my engine.
So with that, i might just be putting a rebuilt 40 on this one.

Brett Buck · « **Reply #8 on:** March 22, 2015, 08:37:33 PM »

Quote from: Dane Martin on March 22, 2015, 05:47:51 PM

\

So people fly these things on Fox 35's.... Does that mean an os25la would fly it? I've never tried it, but i would think the planes too big.

That works very well. One of the better airplanes I have ever flown, including many NATs-quality airplanes, was a Fancherized Twister with a 25FP. Bob Hazle built it, and I flew it at Golden State one year. It was better than my own airplane at the time, that I just got done using to win the contest, and qualified at 4-5 NATS. The Banshee is a very similar if not identical wing.

25FP and the "new" 25LA can fly a Green Box Nobler very well, no problem with a Banshee.

Brett

Dane Martin · « **Reply #9 on:** March 22, 2015, 08:41:33 PM »

So maybe a building tip more than a four stroke tip...
But the doublers are on and flush mounted. So i suppose if i cut out a rectangle and scootch the wing forward, that would be easy enough in the scroll saw. Is it a better idea to move it forward at this point than cutting off some nose? I plan on competing with this plane so whatever is the better choice, im am willing and able to do

Dane Martin · « **Reply #10 on:** March 22, 2015, 08:43:45 PM »

Cool, thanks Brett...
So what if i built the plane light and ran the newest os30fs? That's the same power, right? Then it'd be easier to balance

Tim Wescott · « **Reply #11 on:** March 22, 2015, 08:56:05 PM »

Quote from: Dane Martin on March 22, 2015, 08:41:33 PM

So maybe a building tip more than a four stroke tip...
But the doublers are on and flush mounted. So i suppose if i cut out a rectangle and scootch the wing forward, that would be easy enough in the scroll saw. Is it a better idea to move it forward at this point than cutting off some nose? I plan on competing with this plane so whatever is the better choice, im am willing and able to do

How did you flush mount the doublers?

In my opinion this is a worthwhile enough change that you should go ahead and rip things up as necessary and redo -- even if it means getting some wood from your LHS and making a new fuselage.

If you really, really can't stand the thought of all that work (and if your motor mounts extend back far enough) then just whack the nose off short.

Dane Martin · « **Reply #12 on:** March 23, 2015, 05:43:38 PM »

Ok, the wing is about 1.25" forward. If that ain't enough, then some nose will just come off. I think it will be fine, though. The .40FS ain't that much heavier than a 46LA with a muffler. This should be pretty close. I wanna keep enough room for a tank on the same side as the engine, if i can. Last time i did this combo, i needed about 4 oz for the pattern.

Dane Martin · « **Reply #13 on:** March 23, 2015, 05:47:30 PM »

Quote from: Tim Wescott on March 22, 2015, 08:56:05 PM

How did you flush mount the doublers?

Layed the doublers on the nose with the sheeting down, marked the sheeting and cut it. Then epoxied everything down together between two sheets of glass (my normal little laminating deal)
The fuse is sheeted with 1/16 balsa and the doublers are 1/16 ply.
It's something Pat Johnston turned me onto.

Author Topic: New SIG banshee.... engine choice? (Read 5761 times)

Dane Martin

New SIG banshee.... engine choice?

Bill Little

Re: New SIG banshee.... engine choice?

Tim Wescott

Re: New SIG banshee.... engine choice?

Bob Reeves

Re: New SIG banshee.... engine choice?

Brett Buck

Re: New SIG banshee.... engine choice?

Dane Martin

Re: New SIG banshee.... engine choice?

Bill Little

Re: New SIG banshee.... engine choice?

Dane Martin

Re: New SIG banshee.... engine choice?

Brett Buck

Re: New SIG banshee.... engine choice?

Dane Martin

Re: New SIG banshee.... engine choice?

Dane Martin

Re: New SIG banshee.... engine choice?

Tim Wescott

Re: New SIG banshee.... engine choice?

Dane Martin

Re: New SIG banshee.... engine choice?

Dane Martin

Re: New SIG banshee.... engine choice?