Large Model Association Forum

I have a G38 that's mounted upright in a 1/4 SE5a and is direct drive. Currently fitted is a standard G38 silencer that has been modified to have two pipes exiting sideways and then turning downwards to exit the cowl. My problem is the noise it makes which is loud and unpleasant and needs reducing.

I know there are quite a few 38's about, many mounted upright. What method of silencing do you use?

The aftermarket units like BCM etc only seem to cater for inverted mounting.

Thanks
Chris

Have you got room for a canister exhaust instead?

Nope, no space other than in the tank bay, but then the tank is in the way.

What is the diameter of your two pipes chris. Total diameter too large can have a big effect on noise output.
If you have more than enough power in reserve you could reduce both of these.
Only other other alternative with the same silencer is to open the silencer and fit baffles.
Tony.

Thanks Tony, loads of power, so my next step is to pinch the outlets to reduce the diameter of the pipes and blank one off altogether if necessary.

Fitting baffles is plan B.

Just wondered if there is a common approach the G38 WWI brigade use, particularly on upright installations. I suspect its a custom approach for each application.

Cheers

The guys pack the silencers with, I think, a scouring pad, I will find out more, also, can you not utilise the long exhaust pipe that’s probably a dummy on the side of the fuselage?

As Alan has said, we use "Spontex" pan scourer from Tesco. It's a stainless steel mesh product, similar to wire wool, but doesn't mush up. Cram a good wad of it in the exhaust on the exit side of the internal baffle plate (if fitted), or just make sure it's well away from the engine exhaust port. You will be surprised at how much noise reduction there is. Hope this helps, David Jones.

Thanks for that chaps. I’ll they the cheap option of scourer first. Nice easy fix.... hopefully.
Cheers

Hello Chris I have made two silencers for 38s from the design by Sid King using steel box section and tubing bought from B&Q.

Works very well reducing noise and actually increases rpm by about 500 .

I haven’t got the design dimensions to hand ,but if you have a good torch for silver soldering I’ll try and find it if it’s of interest to you.


A couple of pics of an adapted one

Pete

I have made a few of sids design and they work brilliantly.
I have the drawings of you would like a copy , let me know .
Forget the rest of the so called “silencers, on the market and make one of sids !! I wouldn’t use anything else on a ZG38.

Hello Mike I remember sending you the drawings - what if you could send a copy of the article to Dave Parry to put in the journal,I’m sure it would be of interest to many members,
Can’t find my copy yet.
What do you think?
Sorry Chris for going on your posting but they really work very well.
Pete

I would love an article on this, I have a couple of 38's myself.

Hi Dave
I will send you sids drgs for inclusion in the journal.
It shows all the materials required and the dimensions.
I’m sure a lot of people will benefit from making these for a whole range or engines by just modifying the dimensions.

Thanks Peter and all. Very useful info. Dimensions would be very useful.

Cheers
Chris

Hi Chris using the Z38 standard mount,like youve probably used with the supplied Zenoah silencer ,these are the same thickness and will fit between engine and firewall. They can be made to a width to suit your model - the wider the better.
Hope that makes sense - I can’t find my copy of the specs and very useful instructions but if they go in the journal all the info will be there.
On an SE5 the weight could be useful.

Pete

Thanks Pete. I might have some drawings myself somewhere, as I think I saw something in a magazine once upon a time. I'll have to attempt to find them from wherever I buried them 20 years ago.

As is, the C of G is spot on with no weight, so might not vary too much, i'm happy I didn't need any extra weight, partly due to the lump of a 38 up front.

Mike Ellis wrote:Hi Dave
I will send you sids drgs for inclusion in the journal.
It shows all the materials required and the dimensions.
I’m sure a lot of people will benefit from making these for a whole range or engines by just modifying the dimensions.

Thanks Mike that would be great.

Off the shelf option pictured below.........mounted behind the firewall using the same bolts as the engines radial mount. Really intended for an inverted installation so the exhaust pipe exist the bottom, but no reason why it can't be used on an upright installation......you just have to cut the outlet pipe flush with the top of the engine cowling. You'd just have to move your tank back to fit in the Se5

SUPER quiet.....





Phil

Hi Phil,
We looked at that silencer, and moving the outlet pipe. However there are almost certainly internal baffles which may well complicate the insertion of the tube at the other end of the cylinder.
Dave Berry

Yes, there are 2 internal baffles IIRC making it a 3 chamber muffler. The outlet pipe runs end to end attaching to the 2 internal baffles but is perforated within each chamber allowing the gases to exit.

These are assembled by Toni Clark.........I can ask if they would assemble a 'special' with the pipe exiting the other end if you wish as I have a big order going off to them shortly to stock up various items ready for Haydock.

Phil