SHERDILL

My Feedback: (6)

Hello guys i am looking for a pitts style muffler for a tower hobbies 75 engine,it will be installed upright,please let me know if you know of one...thanks

MasterAlex

Look at tower's site for the .75. it states that the Bisson .76 Pitts muffler fits the Tower .75. www3.towerhobbies.com/cgi-bin/wti0001p

-MA

Rcpilot

My Feedback: (78)

[8D]

SHERDILL

My Feedback: (6)

Thanks master alex but that muffler is for a side mounted engine application,i am installing the .75 upright..

Rcpilot

My Feedback: (78)

No such muffler for that application.

Can you post a pic of the plane and setup? Maybe we can come up with a DIY mod to make it work the way you want?

SHERDILL

My Feedback: (6)

Here are few pics of engine/mount set up...

culver

Looks like a T-28, you could use the bisson but cut the tubes short and connect to tubes going out the scale exhaust area on the cowl. You could mod it to what you want and take it to a welder that can heli-arc it to work for you.

Gray Beard

My Feedback: (-1)

Ijust went out and looked thinking I had one for upright mounting but all of them were for side mounting. You can check Slimline and JTEC to see what they have. Bison isn't the only maker of Pitts mufflers. Seemed to me I had one in the shop someplace but can't find it. Could have been a JTEC, Ihave used a lot of there mufflers over the years.

BadSplice

My Feedback: (1)

could just be me, but it looks like the prop will be sitting awfully low in the cowling. If you moved the mount up and mounted the engine at 90* you could use one of the more available mufflers.

SHERDILL

My Feedback: (6)

Gray Beard you are right about the muffler,i was able to find a J'TEC muffler model JT-901which i think is going to work.Thanks for taking the time to look one up in your shop,much appreciated!

BadSpike i noticed the low angle of prop nut as well only after looking at the pic,i will try to raise it, changing the mount height is not possible cause it will make the engine stick out the top of cowl and 90 does not work becasue of the nose gear retract,Thank you for your input.

Another friend here mentioned that with the pitts muffler i may have tank pressure issues, letme know what you guys think please...?

vasek

My Feedback: (4)

to get the needed pressure you might have to restrict the openings of the muffler either by "squishing" the ends of tubes e bit or inserting a smaller dia alum tubing & JB weld OR just plug one shut.

check the outlet of the original muffler, you should get the total opening area close to that to get the same pressure

Rcpilot

My Feedback: (78)

You can plug one of the muffler outlets with a rubber plug. I've trimmed a tank stopper down before (lots of work) and put the whole assembly in the outlet tube. Then you can run the screw in and tighten it up, just like a tank stopper was designed. It'll squeeze down and hold itself in there.

I've also pinched them with a pair of vise grips. You can usually pinch one completely closed and that will get enough pressure in the fuel system. Or you can try to pinch both equally if you still want 2 exhaust outlets. I always thought it was easier to just pinch one of them completely closed.......... usually the one CLOSEST to the exhaust port of the motor. That forces the exhaust gas to stay in the muffler longer as it travels to the second tube. This helps with pressure in the fuel system.

Gray Beard

My Feedback: (-1)

Ihave seen the tank pressure problem but Ihave never had a problem with it myself. If you do have a problem you just close up the pipe outlet a little with JB weld until it is fixed. You can even completey fill in the pipes about a half inchwith JB and then start drilling them out a step at a time until you hit that sweet spot. A number of ways to get the job done but try it first, most folks don't have any trouble at all.
You may want to remount your engine though, that really is low. Maybe think about side mounting it or going inverted?? Maybe some point in between?? Just a thought.