Help required in making a 50cc silencer

[Paul Hill]

I'm sure it has been asked before and I have searched but not found a great deal. I have a CCPRO 50cc petrol engine, it came with a very lite weight box silencer, poor choice of words as it does anything but silence, since then I have purchased a pits style muffler which has two 14mm ID outlets which is only slightly better. I have been looking at canister silencers all measure from 280 (large diameter) to 325mm in length which is no good to me in a Black Horse Chipmunk. I have room behind the engine to accomedate a box 80x80x130mm I'm now planning on building my own silencer from 2mm ali sheet I have ali tubing 25mm OD for inlet and 16mm OD for outlet and some perforated ali sheet for internal baffles.

My plan was to route the gas flow through internal perforated tubes up to four times in this box (each end of the box will be a compartment) my question is do I fill the box around the baffle tubes with ceramic fibre material or do I leave it empty.

Any thoughts or suggestions please or if you know of a supplier of good small silencers that work I'd be very please to hear from you.

Regards Paul

[John Greenfield]

Paul

Do not fill the box with ceramic or any other material. The oil and burnt carbon in the exhaust gasses will very quickly clog up and fine material in the silencer making it useless. For the same reason if you drill any holes in the tubes for gas flow they should be a min of 5 mm dia, any smaller and they will also clog up after time.

John

[Mike Ellis]

Good effective silencers dont come cheap ! I made silencers for 25 years when I owned Ratby Aeroplanes but even then I wouldnt guarantee 84db @ 7 metres !

If you want an " incowl only" job due to having little or no space behind the firewall to accomodate Krumcheild canisters,then I would suggest you use the type i make for myself now using the principle of a gun silencer, and we all know how quiet those are !!
If you would like to call me I will send you a drawing that I use to make them for ZG 38s. However its just a case of adjusting the expansion chamber slightly to accomodate the 50cc motor . DO NOT RESTRICT THE EXPANSION CHAMBER

The real secret is in the outlet pipes !!

Cant guarantee how quiet it will be, BUT it will be far better than the ones som shops etc sell as " silencers" for DA/and other motors for 50 quid !! and those are a total waste of time !! and should be placed in the nearest dustbin !

Mike Ellis LMA 652

07941024610

[Bob Thompson1894]

Mike- how about letting us all into the secrets? An article with pics in the journal, or post them on here? I am sure that we all all be grateful...

[Chris Lane]

I forget whether or not I have offered this one before. It's old but is from one of the masters.

Chris

Silence.pdf

(234.6 KiB) Downloaded 186 times

[Dave Parry]

Mike- how about letting us all into the secrets? An article with pics in the journal, or post them on here? I am sure that we all all be grateful...

Yes Mike, that would be a great article for the Journal, don't put it on here it will disappear in a few weeks. Good thinking there Bob.

[Paul Hill]

Thanks guys for your advice, I'm looking forward to using your info and having a go at building a silencer to fit the space available all inside the cowl. Have read Chris's attachment has given me some new ideas I'd like to try, if it fails I'll be calling you Mike to purchase one of yours.
I will keep you posted on progress and display some photos when finished.
regards
Paul