RSM tongue muffler with FOX 35, how many holes?

I am sort of new to c/l and I have never ran a FOX 35 before. I just put a Nobler together to try the FOX 35 for fun and feel what this combo is all about. I have bolt on an RSM tongue muffler and it seems I'll need to open a few more holes, power was weak and it was taking too long to kick in 2 cycles when the nose went up.

I am using ThdrBlt glow plug, 10% Nitro 29% Oil(most castor), RSM 10x6 wood prop.

Any tips about how many holes I'll need on this tongue muffler?



Thanks,

Martin

I suspect you are runnimg your Fox too rich. I would first try leaning it out a bit. Can't answer your question, but one can always drill more holes, or close holes by taping them 4-40 and inserting a set screw.

If you can, don't use a muffler.

There is nothing like the sound of a unmuffled Fox 35 Stunt. That is a sound I grew up with and unfortunatly, don't hear much these days.

Music!

Chris Sterner

I drilled another row of holes, if that aint good enough, I'll bust the end of it wide open

I just need the oil to find a away out of the cowl.

thank you,

Martin

>
>I drilled another row of holes, if that aint good enough, I'll
>bust the end of it wide open
>
>I just need the oil to find a away out of the cowl.
>
>thank you,
>
>Martin


You may, indeed, be adding far more holes to this muffler than what you need. A quick check is to put it on a test stand with no muffler and fire it up to operating rpm. Put your tach on it and then hold the muffler up to the exhaust and check what rpm you lose. You shouldn't lose more than a hundred or two rpm if the muffler is good. If it is dragging you way down, then you have a problem. Ironically, some of the stock mufflers will drag it down pretty much.

>You may, indeed, be adding far more holes to this muffler than
>what you need. A quick check is to put it on a test stand
>with no muffler and fire it up to operating rpm. Put your
>tach on it and then hold the muffler up to the exhaust and
>check what rpm you lose. You shouldn't lose more than a
>hundred or two rpm if the muffler is good. If it is dragging
>you way down, then you have a problem. Ironically, some of
>the stock mufflers will drag it down pretty much.

Heya Len!

The RSM TM comes with 2 rows of holes, drilling a third row of holes did improve my engine run. That is a good tip for trying different mufflers, will try that on a few engine and muffler I have here.


Martin

My Foxes do not seem to like the RSM wood 10 X 6 props for some reason. You might try the 10 X 5 APC, de flashed and balanced. That is what mine seem to like best. (that is currently available that is) I have run them with open exhausts as well as Tongue and stock factory mufflers with no problems with that prop and the same fuel mix that you seem to be running.
Bigiron

Well today I flew with it and the engine sound much happier, but still not as strong as I have hoped for. I will try diferent props next weekend and open up the muffler a little more.

What is the typical cable lenght for a Nobler/Fox 35?

Martin

If I recall correctly, in conversation with Larry Foster (L&J fame) the Hobby Fastners (RSM) muffler was designed for the Fox 35. No drilling required. But certainly it would not hurt to open it up some of even run without it at all...

There is alot that can be done of course to the Fox... the RSM prop is an replica of the Top Flight paddle style so it "should" work fine, but my L&J's seem to like the APC real well.

One quick way to pump a little more grunt is to up your nitro to 15% as recommended by Larry Foster. Some would argue that "mostly castor" needs to be entirely castor...

Could even be you need a little more run-in time. Running a gallon through on the ground would not hurt...might help

Lines... .12 X 58' for the Fox equipt. LA/ FP/ Brodak .40 go with 60' I would like to know what others think on lines for this combo. I fly with 58' on anything powered with a Fox 35.

Thanks for keeping us posted...

The RSM props came out at VSC 19, and I was there. Eric Rule told me that they took pitch and chord specs for the TF paddle and Rev-Up, and averaged them. Bart Klapinski tried one, which solved his engine run problem (thought to be vibration related) and used it to win OTS. I believe it was a Fox .35, but maybe not. So, I wouldn't put the RSM prop away just yet! Still, what works on OTS may not be the hot ticket for a light Noblur.

A fair number of locals use the 10-5 APC on Fox .35 Stunts, to good effect. A few use the 10.5 x 4.5 APC. Thunder Tiger has a 10 x 5.5 that could be killa dilla, and Graupner has a 10-5, too. The G's are a lot of load (like APC's)...more than TT's, but they often work very well! Steve

Steve Helmick
Renton, Washington
USA

I like 11 x 5's on Fox stunt 35's. Flying a Taipan 11 x 5 at present.

here is one of my problems then, I was using .015x62' lines that I was using on my RingMaster powered by an Enya SS30.


Well I guess with a little less muffler restriction, a bit more of nitro and 58' lines will get me where I need to be.

Did any of you tried a TopFlite PowerPoint 11x6 with the Fox 35? It seems it will load the engine almost the same as other 10x6 props with wider blades like RMS 10x6 and Rev Up 10x6, isn't that right?


Martin

(snip)
>Did any of you tried a TopFlite PowerPoint 11x6 with the Fox
>35? It seems it will load the engine almost the same as other
>10x6 props with wider blades like RMS 10x6 and Rev Up 10x6,
>isn't that right?
>
>
>Martin
>


Not at all. The Power Point prop is very thick--has a very harsh airfoil. Even with it trimmed down it will load the engine like an 11-6. I have cut 13 inch Power Point props down to 12 1/2 and tried with both the tapered tip and a squared off tip. Didn't seem to make any difference in engine load or performance in the air. Perhaps this is why no other prop manufacturer has gone this direction. Seems to be a gimmic, nothing more. But these will still load like an 11-6 which is what they are.