HOW TO MAKE A PITTS STYLE MUFFLER QUIET!!

[ULTIMATE1]

If you drill the down tubes from the cannister of the pitts muffler from all directions so it looks like cheese or mesh leaving at least 1/2 inch not drilled then put a piece of aluminum pipe at least one inch bigger over it welded to the can cut a piece of 1/8 aluminum flat stock so it just snuggly fits inside the now larger down tube and tight to the original down tube pack it full of muffler packing you can get from any motorcycle shop and screw the 1/8 inch caps from the outside of the outer down tube into the cap you will be amazed at the noise level decrease and zero power loss. Try taking the spark arrester of a two stroke dirt bike and see how loud it is essentially they are just a glasspack as known in the muffler world hope you guys understand ? I drew a quick sketch that I attached I know these work awsome as I roadraced two stroke Honda Motorcycles for years and also wrenched on them I don't know why these r/c airplane exhaust companies don't make them like this I guess they know nothing about muffling just how to divert the exhaust out of the cowl There's my 2 cents worth OH! by the way how do you think silencers for guns are made ? LOOK FAMILIAR????I was making a set in my third year sheet metal apprenticeship class and my teacher took them away thought I was making silencers till I brought the motor and rest of the pitts muffler to prove I wasn't!!
Attached Thumbnails

[forgues research]

	Quote: Originally Posted by ULTIMATE1
	If you drill the down tubes from the cannister of the pitts muffler from all directions so it looks like cheese or mesh leaving at least 1/2 inch not drilled then put a piece of aluminum pipe at least one inch bigger over it welded to the can cut a piece of 1/8 aluminum flat stock so it just snuggly fits inside the now larger down tube and tight to the original down tube pack it full of muffler packing you can get from any motorcycle shop and screw the 1/8 inch caps from the outside of the outer down tube into the cap you will be amazed at the noise level decrease and zero power loss. Try taking the spark arrester of a two stroke dirt bike and see how loud it is essentially they are just a glasspack as known in the muffler world hope you guys understand ? I drew a quick sketch that I attached I know these work awsome as I roadraced two stroke Honda Motorcycles for years and also wrenched on them I don't know why these r/c airplane exhaust companies don't make them like this I guess they know nothing about muffling just how to divert the exhaust out of the cowl There's my 2 cents worth OH! by the way how do you think silencers for guns are made ? LOOK FAMILIAR????I was making a set in my third year sheet metal apprenticeship class and my teacher took them away thought I was making silencers till I brought the motor and rest of the pitts muffler to prove I wasn't!! Attached Thumbnails

I have also toyed with the idea of packing as you suggested but here where the problem could be, we use oil in our fuel, and this is going to get full of oil at one point....
If you do try it, let us know your results.

Roger

[ULTIMATE1]

Roger if you use the proper packing which motocyle shops sell for two stroke spark arrestors and if it is packed properly with the heat and velocity envolved I have never had a oil soaked packing. I had to repack as this stuff only puts up with the heat for so long that's why they sell repacking at the motorcycle shops cause eventually it breaks down and needs repacking all my two stroke race bikes used oil mixture too! In fact in my early days when we burnt real Castrol oil (love that smell) we ran 32/1 which is a high mixture ratio compared with most of todays sythetic oils.

[forgues research]

	Quote: Originally Posted by ULTIMATE1
	Roger if you use the proper packing which motocyle shops sell for two stroke spark arrestors and if it is packed properly with the heat and velocity envolved I have never cad a oil soaked packing. I had to repack as this stuff only puts up with the heat for so long that's why they sell repacking at the motorcycle shops cause eventually it breaks down and needs repacking all my two stroke race bikes used oil mixture too! In fact in my early days when we burnt real Castrol oil (love that smell) we ran 32/1 which is a high mixture ratio compared with most of todays sythetic oils.

That's very interesting Brian, I will have to look into this
Thanks for the info.

Roger

[ULTIMATE1]

Roger here it is and notice the muffler design

[forgues research]

	Quote: Originally Posted by ULTIMATE1
	Roger here it is and notice the muffler design

Thanks, can you tell me if going this route, will be acceptable in sound level , I am really interested in this mostly for my 4 cylinder 52% Edge since I am having problems installing proper mufflers

Roger

[ULTIMATE1]

Roger if you can find a 125cc dirt bike run it then take the spark arrestor off you'll be amazed at the difference of course the longer and larger you make the spark arrestor the quieter it will be IE:the more volume of packing to absorb the concushion of each explosion there is every time the motor fires

[dick hanson]

Once upon a time -- there were mufflers sold for automobiles ( quasi hot rods )- called "Smithy' or Glass pak etc., a very simple and highly ineffective design-
these took the "snap" frequencies out of the pulses and left that satisfying "Drive Inn" rumble (once you pulled the choke out a bit to make firing uneven.

Ah yes -history just repeats it's self.
Motorbike devices were much the same but on two stroke bikes these oiled up - I started with Hodaka - and all these type bikes were required to have as stock equipment " spark arresting "devices on the exhaust.
On our two stroke engine these are not very effective - for a few years , a "muffler(?) was on the market where one screwed in lawn mower canisters to do the same thing . There were wrenched onto the various converted chain saw engines of the period
And tho they were heavy and vibrated , at least they remained noisy and with low power .

[ULTIMATE1]

Snuffler Mufflers & Snuffler Kits

Double Snuffler with smoke for DA 85

Snufflers and Snuffler Mufflers

JTEC's patented Snufflers and Snuffler Mufflers are designed to quite your engine down without having to use a canister type exhaust system. Our patented Snufflers are available for almost any engine and can be bolted to your existing muffler or event mounted remotely.

Our Snuffler Mufflers are designed to be a direct bolt on replacement of your existing muffler and are available for 1.08 - 100cc engines. Snuffler mufflers are available as a single or double snuffler assuring the best performance available.

http://www.jtecrc.com/snufflermufflers.htm
And if i'm correct these don't even have any packing in them?

[ULTIMATE1]

	Quote: Originally Posted by dick hanson
	Once upon a time -- there were mufflers sold for automobiles ( quasi hot rods )- called "Smithy' or Glass pak etc., a very simple and highly ineffective design- these took the "snap" frequencies out of the pulses and left that satisfying "Drive Inn" rumble (once you pulled the choke out a bit to make firing uneven. Ah yes -history just repeats it's self. Motorbike devices were much the same but on two stroke bikes these oiled up - I started with Hodaka - and all these type bikes were required to have as stock equipment " spark arresting "devices on the exhaust. On our two stroke engine these are not very effective - for a few years , a "muffler(?) was on the market where one screwed in lawn mower canisters to do the same thing . There were wrenched onto the various converted chain saw engines of the period And tho they were heavy and vibrated , at least they remained noisy and with low power .

Dick if you actually read my post you would have seen that I actually had already said these were known as glass packs in the muffler world secondly you would think a man of your stature within this hobby and fields beeing lost do to noise would not bash an idea but yet offer some better advice thirdly I guess JTEC is just ripping people off acording to your great knowledge the fact is these do work !

[SURREYRCAV8R]

Mr. Mitchell,
Such animosity at the expense of trying to prove a point. I talked with JTEC, they in fact could NOT guarantee me that my plane would be any quieter using a DB scale, however they said the "snufflers" would take the annoying bite out of the sound of the plane.

Personally I find the sound of a screaming .46 engine more annoying than that of a 100 cc gasser, why, different frequency levels. Truth be known lower frequencies travel farther with a higher sound pressure level than higher frequencies, that is why it is important for guys flying large scale planes to quiet them down as much as possible, otherwise you can hear them a greater distance from the field. Most of the problems arise when you try to muffle an engine, you can also reduce it's performance. You want to reduce the noise of an engine WITHOUT affecting it's performance and/or find the happy medium between the two. Clubs that lose their fields to noise are always unfortunate but if you have a set of guidelines and adhere to them, you should be okay.

Now what I want to know is when did you become such an expert on muffling and quieting airplane engines when the largest plane anyone has ever seen you fly is a 60 sized ARF? Yes some of the technology of motor bikes may in fact spill over to model aircraft, but before you claim yourself as an expert don't you think it would be wise to have at least flown a plane with one of your experimental mufflers?

[dick hanson]

	Quote: Originally Posted by ULTIMATE1
	Dick if you actually read my post you would have seen that I actually had already said these were known as glass packs in the muffler world secondly you would think a man of your stature within this hobby and fields beeing lost do to noise would not bash an idea but yet offer some better advice thirdly I guess JTEC is just ripping people off acording to your great knowledge the fact is these do work !

Well - my experience is that they really are of no real value and the extra cantilevered weight on the basic POS muffler design -assures that the entire thing will overtax the mounting .
I calls em as I sees em. The prop and muffler noise of the oft seen 80cc setupis -to be sure - a pain in the ear -.
Making quiet without loosing power on a two stroke is a real exercise and unfortunately require a well thought out prop (more pitch usually) and a high volume expansion,multiple chamber device
the in cowl devices just don't do the job.
they can not , without seriously compromising power.

[ULTIMATE1]

well Dick I've made a few for sachs 3.2's and had great success but I agree having roadraced and tuned two strokes for many years and your never going to match a canister or tuned pipe which is my personal choice.just because of the volume youcan't do it with a pitts can butt you can knock of a few db's

[ULTIMATE1]

Another thing I've done is wrap the pitts system in thin glass cloth then use high temp silicone and give the whole thing a thin layer of silicone and the cloth keeps it from peeling and it takes a lot of ressonance out of the aluminum pitts can

[flyinglow]

Brian,

Thanks for the info in your post. If you or anyone else tries it in a 150cc or so and can get lower DB's, let us know.