flightcrazed

My Feedback: (13)

Hello everyone,

I decided to try to come up with my own moose cans after seeing one in a thread somewhere. I used a mic light aluminum bottle and a tower hobbies header. Originally I used JB Weld to hold it together, but it doesn't work. Then I found a thread on spadtothebone about moose cans, and tried the RTV silicone. That stuff is INCREDIBLE.. I also tried to connect a copper 90 into the back fo the bottle on the first couple, nothing would hold it in. I noticed on the spadtothebone plans they just drilled a hole in the can so that is what I will try next.. How big or small the hole should be I'm not sure, I tried one that I just pulled the 90 out of but the hole was too big, at least I think it was, it was VERY loud and only gave it a little more kick, we'll see the next time I fly how they do, I have a few made up now, I made the hole about the same size as the hole in the tower muffler...

Thom

flightcrazed

My Feedback: (13)

Hey ya'll,

I just took my plane out back and ran it with the new can. I drilled a 7/32 hole in the new muffler. Seems to run ALOT better. Throttle response was AWSOME!!! Tuned a lot easier, I dont have a tach so I'm not sure about the numbers.. A buddy of mine has a tach but it seems to read very eratic. Hopefully the weather will let me fly this weekend and I'll be able to report further.. Thanks for lookin!!!

Thom

flightcrazed

My Feedback: (13)

O.K. ,

I have never used a tach before today so according to the directions I'm doing it right.. I had my son hold the tach really steady while I tuned the engine to max RPM's then backed it down about 150 RPM's. He was about 3 inches from the prop and got a very steady reading so her is what I found..

I am running a Thunder Tiger Pro 46 with a 12.25 X 3.75 APC prop the motor is less than a year old but was broke in very well and has PLENTY of flights on it.

Tower Muffler @ WOT : 8000 RPM's
My "Beer Can" @ WOT : 11040 RPM's

the tach is the tower hobbies digital mini tach

I hope the flight tests are as good!!!!

Thom

gplarry

Thom,

I would expect the TTPro 46 to hit about 12,000 with that prop.

I wonder if you had the tach set to 3 blades.

If you did then your reading with the beer can muffler is awesome.

I have the same engine and muffler and am interested in making a tuned muffler like the one you made.

The pics are dark. Do you have any that are lighter?

How is the sound level?

Larry

rrh

These things are a lot of fun to play with If you are not flying in any competitions that limit muffler length, you can really get em singing I am always on the look out for the perfect mousse can. I have standing orders in with all the women in the family to save their empties for me and I always roam the hair-do aisles looking for the "perfect" can. There are some beauties in those fancy mall hair styling stores but I have yet to pay 10 bucks to squirt that can full down the drain [:'(] and can't get my wife to buy it either

When you get to really fine tuning them in, get a knife blade that you can shave a little bit of metal at a time out of the exhaust hole. You will keep picking up rpm as you gradually enlarge the hole and hit a point where you don't gain any more. Stop there or you will start to loose rpm by continuing to make the hole bigger.

I had a 9" can on a .25 Norvel and it would turn just under 20K [X(] You have to be careful at those high rpms to not run too lean or you can sieze one up [:@] ask me how I know []

rrh

flightcrazed

My Feedback: (13)

Hello gplarry & rrh,

Well, I have made three of these and have them on two TT46 and one on a Royal 46. It really helps.... The tach was set right, I am sure those readings were bad because I did the test on an overcast day. I checked it out at the field on a sunny day and I am getting about 13,200 rpms from a 12 X 4 prop with my muffler on the Thunder Tigers, running 10% cool fuel. I am not sure about the Royal, I do know it wouldn't hover my Magic Fun Fly before my muffler and it will now. Haven't checked the tower muffler to see what RPM's I get from that. But I really like the throttle response I'm getting, also they are a lot quieter than my original. Just a little louder than the tower muffler. High end needle is about 2 1/4 turns out. I did not put in the "tube" in the inside like the one on spadtothebone, its just a open chamber. I am not sure what is gained from the "tube".

Thom

rrh

Use the tube and you will really see some results The tube inside the can basically makes the pipe twice as long. By varying the length of the tube is another way to"tune" these dudes in. It's all about the reflection of the exhaust pulse and when you get everything reflecting around just right in there, the exhaust pulse helps suck the new fuel charge into the combustion chamber, more than with a standard muffler, and that's where you get your big performance boost. As in any performance boosting devices, there are some trade offs. When you find the peak performance set-up you are going to loose some low speed reliability - won't idle or transition that great- but when it "get's up on the pipe" it will really scream

rrh

flightcrazed

My Feedback: (13)

ok... so should the exhaust port be located at the front of the muffler in order to get the full "double the length" effect?

rrh

Correct, and I try to put it on the bottom so the unburned oil has a place to go

rrh

flightcrazed

My Feedback: (13)

how much space should there be at the back, between the inner "tube" and the can??? I was thinking about using some aluminum from a can and rolling it so its the perfect size and light weight, would this work?

rrh

I like about a 1/4" space between the tube and the can. I've had less but don't want to get restrictive on the flow.

Rolling yer own would probably work. I'm always on the lookout for the perfect tube, too I have used towel bars and fishing net handles and lawn chair legs. The best was one of those telescoping lite bulb removers that someone threw in our work dumpster after the head broke off. Still got a good length of that laying around

rrh

gplarry

I have a Menace fun fly airplane and want to make a tuned muffler for it.

The midrange and response are as important as top end. (but top end is important)

Another important thing is noise.

The Menace is down low and close a lot and can be irritating if it is loud.

I wear ear plugs even with a stock muffler.

There are a lot of old ears like mine in our club that are annoyed by a screaming 2 stroke.

I have been researching the idea of a tuned muffler with an after-muffler that is very quiet but does not restrict.

Oh and it would need to be light and small and cheap and look good.

Any ideas?

Dave McDonald

My Feedback: (19)

Here's my favorite way of making a MCP.

http://webpages.charter.net/rcfu/ConstGuide/MCM.html

gplarry

I have seen the mufflers in the link and they work well.

They are still a bit loud for me so I am back to the question of an after-muffler.

A second mousse can attached to the first might be the ticket.

I expect that there is a way to design a mousse can type tuned pipe that is really quiet and still adds good power.

Has anyone tried this?

GPLarry

rrh

It depends on what you are willing to accept as "good power". The quieter you make it the more you choke the power down. You have to decide what is an acceptable noise level for the power you want and start building your perfect tuned muffler.

rh

flightcrazed

My Feedback: (13)

o.k. I made up a can with an inner "tube"... tube goes back to about 1/2 inch from the back of the muffler, drilled the exhaust toward the front of the muffler. Gained about 300 rpm's, not a noticable difference in power for the weight gain, so I'm leaving them out from now on, they seem to work great without them.. I'm not sure how much I'm gaining over a stock muffler because I dont have a stock muffler. I will check it against a tower muffler again next time I go out.

Thom

VeeAte

I used to race go-karts and to quieten them down in the end they attached a big black plastic airbox onto the carb which believe it or not quietened them down considerably. As long as the tubes running from the airbox to the carb arent smaller than the carb opening we didnt lose too much power. Make sure the air box has double the carb barrel size holes in it.

Not sure how you would go with the prop right there. And not sure if it would lose more power than the Yamaha 100S 2 stroke engines we used to use.

Might be worth a shot to see if it makes them quiet tho. Providing you can find the materials to make it with cheaply of course.