With the stock muffler, my O.S. 50 Sx was turning an APC 12.25X3.75 @ 12,400 rpm
With a Tower Hobbies muffler same prop. 13,200 rpm.
I took the muffler into pieces and I made a longer tube for a total capacity of 200 cc., the same capacity of my Macs tuned pipe including header and silicone hose.
Now my engine with same propeller is turning at 13,800 rpm.
The original tube for the tower muffler is 90 mm long for a total volume capacity of 150 cc, mine is 120mm long.
Hope this will be usefull for somebody.

Regards.

Good job. I just put a Tower Muffler on a 50 SX about a month ago. It worked well.

Where did you get the thin wall aluminum tube?

Enjoy,

Jim

Great post Tiroloco - nice piece of Research & Development you did there! Thanks a lot!

That's a real gem of wisdom I definitely won't be passing on to my ".40 sized Trainer Pylon Racing Class" flying buddies! Heh Heh Heh!!

Thanks again!

Wow! I ALWAYS run the Tower muff. on OS-46/50SX, Irvine-53/ TT Pro-46 etc. and I swear by them--- Good to see you started off with an 800RPM gain!

I am not very good at fabricating stuff so I would probably have trouble extending mine like you mentioned there---

That is awesome for that fun-fly prop.!

Let's see or get a little more info on how you extended it.

Thanks,

Ernie

to late harry you opened your mouth cant wait for my 50 sx amd tower muffler to arrive


let the carnage begin

sideshow racing hahaha

Jim, Razor and Ernie, I made myself at the lathe the thin wall tube from an aluminium ISSP 1 5/8" tube (you can buy this tube where you can buy steel, aluminium, brass for a workshop, this kind of pipe or tube is used for high pressure applications and is seamless).
The original ISSP tube has an internal diameter of 1 3/8 " so you may need to bore it to 38 mm internal diameter and for each side you may need to bore to 39 mm, 1/4" deep to make the front and back plate of the TH muffler fit o.k.
Then make the external diameter VERY CAREFULLY to 40 mm, thatĀ“s because you have a thin wall at the tube.
What is very important to make this mod. work fine is that you also may need to make the pressure fitting hole a little bit bigger, IĀ“ve opened mine to 2mm to get more pressure for the tank, if you donĀ“t make this, you will have problems with the fuel supply airborne resulting in a dead stick (it is my experience!).
Finally, you may need to buy 4mm threaded stainless steel rod and cut it to the new length also you may need a couple of security nuts (those nuts have a piece of nylon in one side) to fit it back again.
I would like to send you all a sample, but it will be expensive to me to send you this from Mexico.
I will post a picture of it when I can get it.

Regards.

Tiroloco,

Thanks. That's a good description.

Enjoy,

Jim

Thanks, thanks! Opening up the hole in the pressure fitting is interesting. I didn't realize that would be the limiting factor in the pressure line. Maybe we should do that on all of them.

Ernie

Thanks Trioloco, You have made some interesting points here. I think the muffler doesn't provide enough pressure on my application and I may try opening up pressure tap a bit as you have suggested. I would like to experiment with muffler length but don't have machinging capability. The original Tower Muffler is an improvement and should be tried by all.