Fox 35 mufflers

[Marty Hammersmith]

Can a Fox 35 tolerate a tongue muffler without overheating? The particular Fox 35 is an oval port completely open without tabs.

[Robert Zambelli]

Yes.
I have been using them for years without any problems.
Bolt on for the modern engines, strap on for the older versions - the ones without muffler lugs.
Bob Z.

[Dennis Toth]

Marty,
Yes, the Fox will run fine with the tongue muffler but mine like 7% nitro, 26% total oil. I mix a qt of Brodak 5%N, 29% all Castor with a qt of 10%N, 23% all synthetic. In the heat of summer if you hear it crackle (this is pre-ignition) I cut the prop diameter to 9 1/2" and run a 6.5" pitch, this keep rpm around 9800 at launch and lap times around 4.7sec.

Randy Smith, Brodak have good tongue mufflers for those with mount tubes or tabs. For the older case with tabs I JB Weld pieces of aluminum tube along the case exhaust to the muffler. This supports the case and prevents the case from squeezing and distorting the cylinder as you tighten the muffler mount bolts.

For the cases without tabs or molded in mount bosses, Stan Frady over on facebook in the PAMPA group makes excellent tongue mufflers for the Fox that have side mount sets screws to secure it, they work great and don't distort the case when tighten them like the older strap on mufflers did.

Best,  DennisT

[Marty Hammersmith]

Marty,
Yes, the Fox will run fine with the tongue muffler but mine like 7% nitro, 26% total oil. I mix a qt of Brodak 5%N, 29% all Castor with a qt of 10%N, 23% all synthetic. In the heat of summer if you hear it crackle (this is pre-ignition) I cut the prop diameter to 9 1/2" and run a 6.5" pitch, this keep rpm around 9800 at launch and lap times around 4.7sec.

Randy Smith, Brodak have good tongue mufflers for those with mount tubes or tabs. For the older case with tabs I JB Weld pieces of aluminum tube along the case exhaust to the muffler. This supports the case and prevents the case from squeezing and distorting the cylinder as you tighten the muffler mount bolts.

For the cases without tabs or molded in mount bosses, Stan Frady over on facebook in the PAMPA group makes excellent tongue mufflers for the Fox that have side mount sets screws to secure it, they work great and don't distort the case when tighten them like the older strap on mufflers did.

Best,  DennisT

Yes, I have one of those setscrew mounted mufflers for an open port Super Tigre. It's a nice design with EXCELLENT fit and finish. They offer the same for the tabless Fox and that's the one I'm looking at.

[Colin McRae]

I also use a tongue muffler on my Fox 35 Stunt engines. Mine are from Brodak and work well. The Brodak mufflers are designed for engines w/ ears. My stunt engines are circa 1975 and have muffler mounting ears. Just have to be careful not to tighten the mounting bolts too tight as the ears are fragile and can break off if over tightened. I have not had any issues so far.

And I run 5% nitro / 29% all castor fuel on my Foxes & McCoys.

[john e. holliday]

As stated in an earlier post,  cut some brass tubing to fit between the muffler ears and the Fox ears.  I also use J-B Welt to hold the tubes in place.

[Colin McRae]

As stated in an earlier post,  cut some brass tubing to fit between the muffler ears and the Fox ears.  I also use J-B Welt to hold the tubes in place.

Thanks Doc (I don't remember seeing the past post you reference.) I will look into adding brass tubing to reinforce the muffler mount as you describe.

I do use a split ring type lock washer on the muffler screws and just make the screws snug and seat the lock washer without over-tightening. Has not been a problem so far. Muffler has not vibrated loose. But the brass tubes will be added assurance to protect the ears which is a good thing.