A little update on this project - I started testing canisters on the 45GX this afternoon.
Since I didn't start until after work ... and I didn't want to upset my neighbors too much ... I didn't get very far into the test. I am using the Evolution 45.01 canister and header as a baseline only because its configuration will not fit in this plane. To use the 45.01, the engine has to lay on its side ... and the tall/narrow cowl would mean the head would protrude out the right side a good 3" or more [
] So ... I will just use that as a comparison to Pe's published performance numbers.
The second canister I will try is a prototype/one-off that I got from a friend that is a distributor for the canister manufacturer. From what I can see when looking down the inlet ... it is a simple pass-thru can with no baffling or chambers. It is a front inlet with a front stinger and its size falls between the Evolution 45 canister and the Evolution 58 canister.
The third "muffler" I will test is one that I made
I used altavillan's guidelines in his thread on building aluminum beer bottle mufflers: [link=http://www.rcuniverse.com/forum/m_7385806/anchors_7385806/mpage_1/key_bud%252Cbottle/anchor/tm.htm#7385806]"Building and tuning, Bud Bottle Mufflers"[/link]
I really just used today to get the baseline with the 45.01 and make sure my test stand was going to do what I needed. I will carry everything to the flying field this weekend and do the actual testing. I will have to make runs gathering the rpm data with 2 props, switch mufflers/canister ... and make runs with the same 2 props. I am starting out with a KS swan-neck header at full length, so after testing both cans with both props - I will cut the header - and perform the tests again - until I reach the best performance. Obviously, this would drive my neighbors crazy
I think my baseline is close to Pe's. His baseline numbers were gathered using a TD75K canister on a full length header with a 3W 21x10 prop - 6650 rpm. My baseline (45.01 can and header) with a NX 22x8 = 6650 (cold canister) and 6530 (hot canister)
I also got a baseline with the 45.01 setup using a 24x8. This one concerns me a bit. Although I got real close to Pe's numbers (24x10 + 45.01 = 5900 rpm), it seems the hotter the canister got the worse it ran. With a cold canister, I got 5880 with the 24x8 prop. As the canister got hotter and hotter, the performance continued to go down. I gave up when it reached 5400 rpm [&o]
Anyway - I will do more testing this weekend and hopefully find a sweet spot with the prototype canister.