[BFlyer]

Is there a difference between front and rear exhaust canisters of a given size in terms of noise reduction and engine power?

I am looking to use a pair of MTW75 front or rear exhaust canisters for a DA 100. These canisters are quite long (355 mm). The rear exhaust version is less convenient to install because of the added length of the exhaust pipe. However it appears to be closer to a tuned pipe than a front exhaust canister, so I am naively guessing that it allows the engine to develop more power than the front exhaust version would allow. Is my naive conjecture true or false?

I would appreciate any guidance on resolving this question.

[rpm]

In my opinion your conjecture is true but I don't have any numbers to prove it. I think it makes sense that rear exit cans will have freer flow. I have had both front and rear exhaust canisters and have been happy with both. Currently using MTW75 rear exhaust with a DA120 and it runs great. Have had DA100 with front exhaust cans and it ran great. I doubt you would notice very much difference, so it the front exhaust better suits the install I would do that.

[RAMJET]

On a 2 cycle they require an expansion chamber to optimize performance , all cans used on R/C models are way to small to have any real power affect . yes it may or may not cause the engine to produce power in a different place then a standard muffler but they are not even close to having a large enough volume to optimize performance to any real degree . as far as the exit port ,it is used more as a pressure relief valve to keep pressure constant in the pipe, This combination of a expansion chamber that should be equal to the expanding gasses (not possible in a R/C aircraft) and the size of the exit port need to be in balance to keep the incoming fuel charge from going straight out the exhaust port . The size of the can and the diameter of the exit port will have more effect then the location of the exit port . Pressure will drop at the same rate inside a tire no matter where you puncture it. LOL. cheers

[grizak]

You won't notice much (if any) difference in performance between an MTW front or rear dump canister.

If you really want to maximize performance, you may want to consider the MTW TD80 instead of the TD75 - the TD75 is essentially discontinued now. The 75s work very well - but the 80 is an improvement - it is slightly longer (just a few mms).

[BFlyer]

Thank you for all the advice. My next question is probably the subject of an ongoing debate. Do canisters improve or reduce the engine power output compared to standard mufflers?

John and Jase Dussia’s YouTube videos on Extreme Flight airplane assembly and setup show their preference for standard mufflers. Is it because of power, weight or engine spool-up time?

Interestingly the new Extreme Flight airplanes that use carbon fiber for fuselage structure don’t have canister wells. Is this because most customers install standard mufflers, or because modern canisters plus header pipes isolate the exhaust flow to the exhaust pipe really well?