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April 01, 2020, 12:16:42 pm

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DLE 20cc going deaf from the noise

Started by paulinfrance, December 01, 2019, 08:07:44 am

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paulinfrance

Hi, I was contemplating getting a 2 metre Spitfire and a 35cc DLE for it ^-^ , however after flying my DLE 20cc after my OS .80 four stroke Hurricane, I decided that it would be too noisy and didn't go ahead with it. :embarassed:
 'But' now I have come up with the idea  :co of fixing 'back to back' another 20cc RA exhaust on my ME 109 and see what it sounds like, Has anyone tried this ?.
Mode 2 THE only way to fly

itsme

Yes, I did this on a ST90 powered MR Hurricane many years ago. A header to a silencer and a pipe to a home made can in the fuselage. It was whisper quiet. The DLE is a good make of engine, but the 'silencers' are rubbish. You will lose a bit of power, but that is a powerful engine. Incidentally, after market cans are available, try Just Engines.

FrankS

More silencer volume should reduce the noise. I've bought one of these to try on my DLA32cc https://www.ebay.co.uk/itm/Stainless-Steel-Silencer-Gas-Engine-Exhaust-Pipe-for-RC-Boat/192834998983?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D20190606144518%26meid%3D11c94d92a0ca4c9d85712e12acce304a%26pid%3D101072%26rk%3D2%26rkt%3D12%26sd%3D183310443634%26itm%3D192834998983%26pmt%3D0%26noa%3D1%26pg%3D2546172&_trksid=p2546172.c101072.m2109

But for now I've gone back to glow with a Laser 150!

paulinfrance

Quote from: FrankS on December 01, 2019, 08:49:16 amMore silencer volume should reduce the noise. I've bought one of these to try on my DLA32cc https://www.ebay.co.uk/itm/Stainless-Steel-Silencer-Gas-Engine-Exhaust-Pipe-for-RC-Boat/192834998983?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D20190606144518%26meid%3D11c94d92a0ca4c9d85712e12acce304a%26pid%3D101072%26rk%3D2%26rkt%3D12%26sd%3D183310443634%26itm%3D192834998983%26pmt%3D0%26noa%3D1%26pg%3D2546172&_trksid=p2546172.c101072.m2109

But for now I've gone back to glow with a Laser 150!

 Thanks but  your lien goes nowhere for me,,
Mode 2 THE only way to fly

British Victory

PIF, it should give you a clue. You should have googled instead of complaining. I did and it showed the item at £8.68.
Has CS gone out the window?
there's only one f in RCMF,
               John

paulinfrance

Quote from: British Victory on December 01, 2019, 10:17:07 amPIF, it should give you a clue. You should have googled instead of complaining. I did and it showed the item at £8.68.
Has CS gone out the window?


 ???? what's PIF and £8.68 ?.
Mode 2 THE only way to fly

RobC

flying's easy - it's getting it back down in one piece that's the hard part

paulinfrance

So I suppose that this is a PIF ?,

 I will order one ( or two ) and see how they go,,
 thanks to both.
Mode 2 THE only way to fly

itsme

be warned- it doesnt come with a battery! :)

paulinfrance

Thanks I have Ordered 2 with some tubing that I will solder on the side wall
to keep it in the cowling.
Mode 2 THE only way to fly

paulinfrance

All arrived today, the silencers weigh 100 grams each and the tubing a bit heavy at 85 grams the 20 cm, any cheap sources for the ptfe heat resistant tubing ?, I might also be in the market for 90° tubing but cheaper than Krumsheid ?.
Mode 2 THE only way to fly

itsme


paulinfrance

December 14, 2019, 12:30:28 pm #12 Last Edit: December 14, 2019, 12:37:15 pm by paulinfrance
Quote from: itsme on December 14, 2019, 12:18:48 pmMick Reeves do stainless tubing.

Thanks I will have a look before Britain sets sail for the USA in January,, ::)  :D

 Just looked, nothing big enough, I will se if our 'Helicopter' man has some bending gear,,
Mode 2 THE only way to fly

PDR

Might be worth talking to M-Machine. They stock a range of stainless tube, mainly 304 and 316. Either will work - 316 is better at high temps, but 304 is easier to machine and silver solder.

M-Machine usually have more stick than they list in the catalogue so it's always worth sending an email describing exactly what you're looking for and asking how close they can get to it. They'll also usually cut it to shorter lengths free, so if you want five 100mm lengths ask them to cut it for you rather than just asking for 500mm.

PDR
There are no shortcuts on the long, hard road to success. But if your dad's rich there could a limo service...

paulinfrance

Thanks, I was astounded today by the racket my OS .61 FS made in my SE5a today  :o yes flyable here,,  :''

102Db at 1 metre, flat out,,
Mode 2 THE only way to fly

paulinfrance

Dle 20 ra exhaust 2-2048.jpgDle 20ra exhaust 1-2048.jpgAnother Sunday flying,
OS .61fs on the grass only 92 Db
OS 120 two stroke on grass 102Db
Dle 20cc on grass 99 Db,

GLS didn't deliver my Tiger Moth as promised for the thirt time so I spent my day it making my exhaust / silencer for Dle 20ra powered  P 47,
200 grams,,
Mode 2 THE only way to fly

THE BLACKBIRD

Now that looks very neat work there Paul, i like it
The man that never made a mistake
Never made anything

flynn

December 16, 2019, 19:06:39 pm #17 Last Edit: December 16, 2019, 19:07:53 pm by flynn
Quote from: paulinfrance on December 16, 2019, 16:19:52 pmGLS didn't deliver my Tiger Moth as promised for the thirt time so I spent my day it making my exhaust / silencer for Dle 20ra powered  P 47,
200 grams,,

Wasn't it GLS that had a habit of not delivering stuff and charging you a bucket load to contact them on a premium rate number?.. I hope it arrives soon!  I think they also tried charging for a re-delivery when they claim you weren't there to accept delivery.......

https://www.trustpilot.com/review/gls-group.de

paulinfrance

Yes .90€ a minute >:(  only to be told to go on line with your delivery N°,
there is NO way to talk to the delivery end, I did get one person a Toulouse, who also gave me the same N° and another who only dealt with the 'sender' and who also gave me the crappy N°,,

If anyone wants it ( I have night mares over it ) it's 0806006006

The only problem is Hobby King give you them to deliver,, or rather to loose your parcel,, :banghead:
Mode 2 THE only way to fly

itsme

I got an 18x6 gf prop for my OS 40cc Four Stroke from HK (they were the only stockist) the other day. It came on time, but I had to explain to my other half that the massive box it came in only contained one prop.. and bundles of airbags. I could have got your Tiger in it.

paulinfrance

Some sellers are silly, I ordered 2 wiper blades for my Jag and a rear one for my Peugeot, the same company and all in stock, the jag ones came in a box
50 x 20 x 10cm and the Peugeot one came in a box 80 x 20 x 10cm both on the same day, saving the planet :study:


Ps NOT gls,, :-X
Mode 2 THE only way to fly

paulinfrance

Ready to finish off my silencer system,

92Db 8.700rpm for around 30 seconds then a steady 8.400 rpm,,
and a really nice sound,,  :af Dle twin muffelers 92db-2048.jpg
Mode 2 THE only way to fly

paulinfrance

All finished,,
90Db 8.550 rpm and 280 grams + the weight of the last two jubilee clips,,
Mode 2 THE only way to fly

FrankS

What distance was measured at that Paul?

paulinfrance

As in the French reglementation, 3 metres distance and 30cm from the ground in this case Grass,,,
Mode 2 THE only way to fly

FrankS

So that equates to 82.6 Db at 7m, so should be possible to get it meet the UK recommended 82 at 7m, thanks

paulinfrance

I flew it yesterday  without the engine cowling, the sound is really quiet in the air
it sounded more like an old 10cc methanol engine, so the cowl will be cut out so that
I can get it back on, the  receiver battery will be moved back to get the  the balance point right

 Finally 94Db 8.550 rpm on a  16 x 8 master airscrew
my friends one 102Db 7.550rpm on a 16 x 8 Graupner

 both the same Dle 20RA,,,

 Funny how the DB readings seem to change, all with the exception of my last readings and flight were taken in my garden with my plane and the DB meter in the same place and height,,,
Mode 2 THE only way to fly

itsme

Ground density can change it. It will be louder on tarmac than soft earth for instance.

paulinfrance

Yes, our regalement is 94Db on a tarmac or concrete surface and 92Db on earth or Grass
Mode 2 THE only way to fly

paulinfrance

I am having so much fun with my "quiet' P 47  :af that I decided to order the Dle, "canister" kit for my 20RA in my P 40,
So with the silencer delivered with the engine it gives me 100 Db at 8.550 rpm but on an APC 16 x 8,,, not a master airscrew,
rain next week so here we go,,dle.png
Mode 2 THE only way to fly

paulinfrance

Mode 2 THE only way to fly

paulinfrance

Run up in my garden this morning,, It sounds nice on the ground, especially at idle, but throttling up is now slow and rich in the mid range but finally it does goes full throttle;)
but down to 8.000 rpm ( 8.300 to start with ) after 30 seconds of running, the 'noise' is down to 95Db,  funny on the 90DB range 96 on the 100 DB range 94,,
I won't fiddle about with the carb settings to I fly it, :study: 
Mode 2 THE only way to fly

itsme

Couple of my buddies are building BN Islanders for two DLE20s. (Designed by Paul Hughes, Hughes Model Aircraft) The aim is to keep the engines in cowl, and a big discussion was held in the pub last night. Looking at the standard exhaust, it seems on the large size for a 20 - it is certainly larger than a standard Z38 exhaust, and the outlets are far larger. So the plan is to stiffen up the sides of the exhaust, to take away some of the crackle, with Ali strips welded to them, and then close off one of the outlets completely.
Not trying to get down to whisper quiet- we dont have any problems that way- but just to make them more pleasant to the ear. The BCM silencers bought for them are far too big, will stick right out, and would be enough size for a 50cc! Power is not a concern, two 20s will be overkill, and most of the time these models will be cruising at half throttle anyway. We will be doing a bench test of them soon, so I will keep you informed of the results.

paulinfrance

It won't work !, I made myself an exhaust from steel for my Rcgf 15cc,it's 30mm x 30mm x 100mm and the outlet is Dia 16mm, it weighs in at 200 grams and Dle 20cc ra exhaust weighs 98 grams with the two pieces of tube and hose clips, my steel one is as noisy the only other solution is two 'boat ones which I have fitted to my P 47.
I tried one boat exhaust but I lost so much power with the double ones only 300 rpm.DLE and Rcgf silencers.jpgDle 20 ra exhaust 2-2048.jpgdle 20 P 47 exhaust.jpg
Mode 2 THE only way to fly

paulinfrance

Quote from: paulinfrance on March 02, 2020, 10:25:50 amRun up in my garden this morning,, It sounds nice on the ground, especially at idle, but throttling up is now slow and rich in the mid range but finally it does goes full throttle;)
but down to 8.000 rpm ( 8.300 to start with ) after 30 seconds of running, the 'noise' is down to 95Db,  funny on the 90DB range 96 on the 100 DB range 94,,
I won't fiddle about with the carb settings to I fly it, :study: 


I lied, I just fiddled with the Carb settings ( Monday Afternoon ) $%&
Mode 2 THE only way to fly

paulinfrance

I flew it this afternoon, In the air it seemed to have the same power, it sounded like an old OS .61 Gold head on an oversized tuned pipe,, ::) , lovely,, :co 
 on the ground 8400 rpm, no stuttering and both flights went well.  :af
Mode 2 THE only way to fly