Can you make a plane quieter

[John Smith 50]

Possibly a daft question, not too sure.

I have recently purchased an Edge 540 74" with a DEL 30CC. Its my first non electric plane and I am a little concerned that the noise may annoy the land owner where I fly.

Can they be made quieter at all? Silencers, mufflers? I don't really know a lot about this side.

[Simon Chaddock]

I presume you are flying with its factory exhaust silencer. If not then you will indeed annoy people and would most unlikely be allowed to fly like that at any club!

If you are asking to quieten it down more than the standard then a bigger more complex exhaust system certainly would but at a price. Ask Just Engines they may be able to advise.

Of course a two stroke is inherently noisier than a 4 stroke!

[Bob Cotsford]

Search for JMB, MTW or Krumsheid (KS) exhaust systems. Props style, size and material all make a difference too. Take a look at the large model build threads on here as you will find some good tips on exhaust installation for 2 strokes.

[John Smith 50]

Posted by Simon Chaddock on 25/10/2016 16:26:26:

I presume you are flying with its factory exhaust silencer. If not then you will indeed annoy people and would most unlikely be allowed to fly like that at any club!

If you are asking to quieten it down more than the standard then a bigger more complex exhaust system certainly would but at a price. Ask Just Engines they may be able to advise.

Of course a two stroke is inherently noisier than a 4 stroke!

Im not really sure if it is the factory exhaust or not, I think it has one of these on it. I will have a look and see what I find. Thanks guys

[Engine Doctor]

Hi John . Dump the standard /supplied silencer as they are not fit for purpose. As Bob suggests the Krumsheid silencers are excellent . Not cheap but good well made items, I can't vouch for the other makes. Open light weight airframes amplify noise caused by vibration so balance everything Inc spinner. Props are often a culprit  with large diameter props the tips go supersonic . Keep the pitch as high as you reasonably can.

[Peter Jenkins]

John, I run an AGM 30 (DLE 30 clone) using one of these canisters (about £46). The muffler supplied with these engines is useless. The Edge may well have a tunnel for a canister which will make this a viable solution. As mentioned, the choice of prop is also important. I use a Falcon Beechwood 17x10 (£11) and I also use an extended carb intake trumpet (£23) - this shields the intake noise by putting the carb intake inside the motor box - you may need to widen the hole in the box for the trumpet to fit. I got my intake trumpet from IAD Designs but there must be others who sell them as well. All of these have made the engine noise comparable with a 120 glow and quite acceptable. I've yet to measure the noise with a meter but I'm hopeful it will meet 82 db. The aircraft I'm flying is an HK Sbach 30 cc which tips the scales at 5.3 Kg and the vertical performance is unlimited.

A solution that will cost around £80 ain't bad value!

[cymaz]

The drumming effect caused by vibration on a lightly structured airframe can cause all sorts of issues as well.

Oops, sorry Engine Dr, didn't read your post fully until it was too late....

Edited By cymaz on 25/10/2016 19:45:41

[iqon]

try a 19 x 8 prop.....if you have the ground clearance.. as for exhausts, i have given up on the cheap ones and waiting for a better one to come into stock ( its only been 6 months )..

[eflightray]

Posted by John Smith 50 on 25/10/2016 15:45:51:

Possibly a daft question, not too sure.

I have recently purchased an Edge 540 74" with a DEL 30CC. Its my first non electric plane and I am a little concerned that the noise may annoy the land owner where I fly.

Can they be made quieter at all? Silencers, mufflers? I don't really know a lot about this side.

Almost answered your own question. Throw that noisy lump away and convert it to electric.

To be a little more politically correct, remove and sell the IC engine

Ray.

[John Smith 50]

Posted by eflightray on 25/10/2016 20:03:06:

Posted by John Smith 50 on 25/10/2016 15:45:51:

Possibly a daft question, not too sure.

I have recently purchased an Edge 540 74" with a DEL 30CC. Its my first non electric plane and I am a little concerned that the noise may annoy the land owner where I fly.

Can they be made quieter at all? Silencers, mufflers? I don't really know a lot about this side.

Almost answered your own question. Throw that noisy lump away and convert it to electric.

To be a little more politically correct, remove and sell the IC engine

Ray.

LOL If all IC's fly like this im ditching the leccys!!!

Im ordering a different prop as the one that came with it was turnigy, I think its an 18x10, I was going to get a XOAR either 18x10 or 19x8. I will have a look at the exhausts as there are far more options than I realised.

[John Smith 50]

Are falcon props any good? do they come balanced properly?

[John Smith 50]

Posted by Peter Jenkins on 25/10/2016 18:58:33:

John, I run an AGM 30 (DLE 30 clone) using one of these canisters (about £46). The muffler supplied with these engines is useless. The Edge may well have a tunnel for a canister which will make this a viable solution. As mentioned, the choice of prop is also important. I use a Falcon Beechwood 17x10 (£11) and I also use an extended carb intake trumpet (£23) - this shields the intake noise by putting the carb intake inside the motor box - you may need to widen the hole in the box for the trumpet to fit. I got my intake trumpet from IAD Designs but there must be others who sell them as well. All of these have made the engine noise comparable with a 120 glow and quite acceptable. I've yet to measure the noise with a meter but I'm hopeful it will meet 82 db. The aircraft I'm flying is an HK Sbach 30 cc which tips the scales at 5.3 Kg and the vertical performance is unlimited.

A solution that will cost around £80 ain't bad value!

I'm not sure it has room for one of those unfortunately.

[Former Member]

[This posting has been removed]

[Steve Balaam]

I fitted a DLE30 to a modified 1.20 Electric size GB Models Yak 55

I fitted a DUO silencer from Just Engines and a Falcon 18X8 prop for running in

This combo runs very quietly and I'm very impressed with it

Steve B

[Peter Jenkins]

John, I used to think Xoar props were great till I used Falcon. I now just use Falcon. No props are perfectly balanced IMHO. I've had to balance Xoar, Falcon, APC you name it. If you don't have a prop balancer then it's a great investment. Also, it is sometimes the hub/hole that is the problem so that the blades can be balanced with the heavy spot on the prop hub at the bottom but turn it round and it will not balance. You need to remove some weight from the edge of the hub - carefully!

[chris larkins]

A model can be modified to have a canister fitted even if it was not originally designed this way. The photo's below show my Seagull Edge 540 v2 fitted with an MLD 35cc petrol engine and an internal canister muffler. The firewall was opened up with an appropriate size hole saw, I also made up a liteply ring which fits around the rear of the canister to keep it secure, both the firewall and liteply ring are lined with silicon tube split along its length to keep it secure and reduce any vibration. This set-up with a Biela 20 x 8 prop came out at just under 82db measured on my club's noise meter.

[John Smith 50]

DO any or all of these exhaust options require the engine to be re-tuned at all? I bought it second hand so haven't had to touch the engine and wouldn't really know where to being tbh.

[Denis Watkins]

Chris Larkin's installation is "top drawer" and a fine example to us all on noise reduction. Some fine tuning will be needed with any pipe change, but the motor will not be far out

[stu knowles]

I agree that almost all of the generic exhausts (as standard) are useless as silencers, even the larger volume Pitts style do little to reduce noise. However, (IMHO) the main reason for this is that the outlet area is massive. I have two engines where I have blocked off one outlet completely and reduced the diameter of the remaining one by about half.

There is some loss of performance but the noise output is far more acceptable. Some in the club have used commercially available 'stinger' inserts which also reduce the outlet size and work well.

Canister silencers have the largest volume and are the most effective, although I note with interest that many have a single outlet of small diameter.

Most of my mods use the aluminium weld bought from the dutch? guy at the Nats which has allowed me to chop and modify standard exhausts to fit inside cowls AND be acceptable as silencers

 

 

 

 

Edited By stu knowles on 26/10/2016 10:12:56

[Bob Cotsford]

Re the Turnigy props - I've found the Turnigy Aerostar wood props to be quite good. I bought some expensive Fiala props for my Acrowot and WotsWot XLS and after trying them I'm going back to the 18*10 wood Aerostars.

It might be worth adding a couple of these to the Pitts outlets, they are available in 30 and 20 size so one or other should fit your silencers outlets.

[Engine Doctor]

Posted by John Smith 50 on 25/10/2016 20:48:27:

Are falcon props any good? do they come balanced properly?

Not sure about Falcon props but Xoar props are very good quality wood , well balanced and with a good finish. Any further balancing can usually be achieved by a coat of varnish on the light blade.

[John Smith 50]

Posted by Bob Cotsford on 26/10/2016 10:38:03:

Re the Turnigy props - I've found the Turnigy Aerostar wood props to be quite good. I bought some expensive Fiala props for my Acrowot and WotsWot XLS and after trying them I'm going back to the 18*10 wood Aerostars.

It might be worth adding a couple of these to the Pitts outlets, they are available in 30 and 20 size so one or other should fit your silencers outlets.

I have seen them on gashanger, does anyone know if they work ok or not?

[John Smith 50]

Posted by Engine Doctor on 26/10/2016 10:41:29:

Posted by John Smith 50 on 25/10/2016 20:48:27:

Are falcon props any good? do they come balanced properly?

Not sure about Falcon props but Xoar props are very good quality wood , well balanced and with a good finish. Any further balancing can usually be achieved by a coat of varnish on the light blade.

Cool, I have order a XOAR prop mainly as a spare but I will give it a go and see if it makes any difference to the noise as well.