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Need to quiet down my DL 50

Old 06-10-2008, 12:55 AM
  #51  
Rfabbre
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Default RE: Need to quiet down my DL 50


ORIGINAL: Cambo

ORIGINAL: dick Hanson


ORIGINAL: pe reivers

No,
In my .15 diesels, 8x6 graupner 3-blades, in my gassers I use Mejzlik.

Today I test flew my "new" 1/4 scale piper cub (@25lbs) with 58ccMVVS, side muffler and much reduced stinger outlet. Test prop was a 3W 22x12, and the engine was quite silent. Still enough power vor nearly vertical climb.
I had planned to put on a 22x10x3 Mejzlik, but the plane is a floater and needs a prop that puts the brakes on so I can land on the strip instead of the ditch at the strips end. So I will choose a 24x8x2 for the next tests. This goes to show, that there is not always freedom of choice. The plane has a voice in this as well.
No one will like this -as you actually have to construct it - but it is incowl
the problem is getting enough volume and no exhaust port restriction and NONE of th commercial Pitts do this as well as needed - the large Supersonic works well but noise is still high.
You can't have your Kate and Edith too-
I was thinking of doing such a thing myself. I asked before but seemed to get no reply. Why can't one just make a "canister like" large chamber can and run it back behind the engine. What if you placed a canister sideways parallel to the engine. Oh, and were do you get headers that make a full u turn.

Cameron

Cameron,

That's exactly what I did,

Here are a couple of pics. One shows the size of the can compared to the stock muffler. I don't have any way to measure sound level but it is quieter than the stock muffler.



Rich

PS-PM me if you are interested in specifics.
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Old 06-10-2008, 07:17 AM
  #52  
pe reivers
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Default RE: Need to quiet down my DL 50


ORIGINAL: JoeAirPort

ORIGINAL: pe reivers


ORIGINAL: ukmike

Hello.
The standard DL silencer can be easily modified to reduce the noise and with very little cost.
Just get some tube that is a tight slide fit into the existing outlet and blank off one end. Slide it into the outlet as far as it will go (blanked off end first ) then mark and cut it to the same length as the existing one also mark which part of the tube is actually inside of the cannister section.
Drill 4 x 1/4" holes evenly spaced into the new tube at a point that is inside the cannister body. You now have a restrictor that you can "tune" by adding more holes of varying sizes to acheive the desired effect. The 4 starting holes will be enough to get the engine to run. A little power loss will be inevitable.
The new restrictor is held in place by drilling a couple of holes thu' both tubes and secured with self tapping screws.
When you are happy with the "tuning" the fix can made permanent by smearing a little exhaust compound around the the restrictor tube as you finally fit it.

Good luck.
Mike.
This will severely reduce the available power. It is the system I use when I do not have much time (most of the time), and I can spare to wring in a few extra cubic inches to compensate for the stupid approach.

Much better is to eliminate as much of the prop noise first by:
as first and most important resource, increase disk load without increasing rpm
so: Increase engine LOAD AT LOWER RPM
DO SO BY INCREASING PITCH, NOT DIAMETER. This keeps tip speeds down and away from near sonic fluid flow over the airfoil (air also is a fluid)
As second consideration, increase the number of blades. In a three bladed prop, narrower blades will perform surprisingly well! (disc coverage factor) There is a limit to increasing blades, so increasing diameter is next.

PE, I wish people like you could get points for rudeness and banned from the site after 100 points. You would have been gone a long time ago. I don't like seeing people being rude to other people who come on this site to enjoy themselves. You ruin it !!!

I am not aware of being rude, and I certainly did not mean to be. Please explain where I went off the track.
I certainly do not like your comment, and think it is way off topic, without adding anything to the conversation at hand.
Old 06-10-2008, 07:54 AM
  #53  
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Default RE: Need to quiet down my DL 50


ORIGINAL: dogshome

ORIGINAL: buck1856

If just about every gas engine at your field failed then all you guys that failed just need to go find a place to fly by yourselves.We have an old abanded air strip that we found a hole in the fence,no one cares yet.

Buck, I totally disagree with that viewpoint. It won't do you any favours finding another site if someone DOES care and kicks you off because of the noise. I hope you were kidding [] ? Kweasel has put it bluntly but correctly - learn how to silence your aircraft [sm=49_49.gif].


PE Reivers:- You've not commented on the muffler insert? Granted it will lose some power but as a cheap solution to fly an unflyably noisy plane in a noise limited area, it works. Cambo, the original poster is going to try it, if it still gives the power he needs and gets the noise down then great! I need a newer car with a more efficient engine; but I can't afford to buy one just yet.
A muffler insert is of course one possibility. I fear that some people here take offence on my using the words "strupid approach", just because not much thought about the application is needed. I do think that it is just that, although I often use it myself. It is very effective in muffling the engine, but it does so by choking it. consequently, power is reduced too much.
Old 06-10-2008, 09:19 AM
  #54  
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Default RE: Need to quiet down my DL 50

ORIGINAL: Rfabbre


ORIGINAL: Cambo

ORIGINAL: dick Hanson


ORIGINAL: pe reivers

No,
In my .15 diesels, 8x6 graupner 3-blades, in my gassers I use Mejzlik.

Today I test flew my "new" 1/4 scale piper cub (@25lbs) with 58ccMVVS, side muffler and much reduced stinger outlet. Test prop was a 3W 22x12, and the engine was quite silent. Still enough power vor nearly vertical climb.
I had planned to put on a 22x10x3 Mejzlik, but the plane is a floater and needs a prop that puts the brakes on so I can land on the strip instead of the ditch at the strips end. So I will choose a 24x8x2 for the next tests. This goes to show, that there is not always freedom of choice. The plane has a voice in this as well.
No one will like this -as you actually have to construct it - but it is incowl
the problem is getting enough volume and no exhaust port restriction and NONE of th commercial Pitts do this as well as needed - the large Supersonic works well but noise is still high.
You can't have your Kate and Edith too-
I was thinking of doing such a thing myself. I asked before but seemed to get no reply. Why can't one just make a "canister like" large chamber can and run it back behind the engine. What if you placed a canister sideways parallel to the engine. Oh, and were do you get headers that make a full u turn.

Cameron

Cameron,

That's exactly what I did,

Here are a couple of pics. One shows the size of the can compared to the stock muffler. I don't have any way to measure sound level but it is quieter than the stock muffler.



Rich

PS-PM me if you are interested in specifics.
nice - If you want even more muffling use even larger can and make a double chamber inside .
The BEST two stroke muffling today is used on two stroke scooters and non performance small motorcycles - look at those designs
On a more POSSIBLE practical approach if possible select the largest can available - a little larger - can make a huge difference as th volume increases a LOT with only a bit larger outside dimension.
This then allows you to use a smaller moffler outlet -
The theory goes like this : each exhaust pulse can expand more easily (quickly) which brings in MORE fuel charge for next power stroke
the larger can also cools the charge more- as the pressure in the can reduces ( reduce pressure and you reduce temperature)
a smaller outlet is then permissible-each pulse then extends time wise and if the can were large enough and multiple changes in direction of flow happened -the outlet sound would become a "whoose" rather than a "pop" .
The theory is a 100 years old -at least . well proven.
The weight and power are the most inportant parts of selecting a gasser for a model and the cheaper products on the market simply do not address noise -why ?
the majority of buyers simply never have cared about it .
many want the noise -the louder the better "look at me!"
Old 06-10-2008, 10:30 AM
  #55  
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Default RE: Need to quiet down my DL 50

Dick, that is what i was thinking of doing. Taking a trip to the wallgreens and grabing some cans. Maybe a two chamber setup with baffle but not sure if that is practical.

So the questions i need answered to do this

1: Am I going to need to find access to a tourch to braze? or will GB weld hold up. (I have a couple buds that can probabley hook me up).

2. What type of material should i be using to make the can. Aluminum, tin, ect.

3. Were do i get headers that rap around like that and are really short. I need to find one.

4. Finally, were do i get the actual material for the exit pipe? I can't seem to find any thin metals



Thanks
Cameron
Old 06-10-2008, 10:49 AM
  #56  
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Default RE: Need to quiet down my DL 50

ORIGINAL: ukmike

Pe Reivers.
Sorry if you think my approach is "Stupid". but it does offer a very low cost alternative which is what the writer asked for originally.
Also, as I stated in my reply, I have used it many times to quiet existing installations which has made an unflyably noisey plane, flyable.
If the results are not liked then just remove the restrictor, refit the self tappers and fly away, Noisely.
Mike
PE, I guess both of us thought your comment was rude. You said his approach was stupid. Go back and read it. Maybe you didn't mean to be rude but that's how it reads.
Old 06-10-2008, 11:31 AM
  #57  
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Default RE: Need to quiet down my DL 50


ORIGINAL: Cambo

Dick, that is what i was thinking of doing. Taking a trip to the wallgreens and grabing some cans. Maybe a two chamber setup with baffle but not sure if that is practical.

So the questions i need answered to do this

1: Am I going to need to find access to a tourch to braze? or will GB weld hold up. (I have a couple buds that can probabley hook me up).

2. What type of material should i be using to make the can. Aluminum, tin, ect.

3. Were do i get headers that rap around like that and are really short. I need to find one.

4. Finally, were do i get the actual material for the exit pipe? I can't seem to find any thin metals



Thanks
Cameron
You do need a welding setup and th ebest cans are small liquid container paint cans they are all steel and very durable
th tubing - call Desert aircraft for tubing
- the headers - Mac's mufflers .
Old 06-10-2008, 11:38 AM
  #58  
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Default RE: Need to quiet down my DL 50

Dick does macs mufflers make mufflers for the DL/DA or do you have to order one custom biult.
Oh, and those paint cans are exactly what i was thinking.

Cameron
Old 06-10-2008, 12:14 PM
  #59  
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Default RE: Need to quiet down my DL 50

ORIGINAL: Cambo
So the questions i need answered to do this

1: Am I going to need to find access to a tourch to braze? or will GB weld hold up. (I have a couple buds that can probabley hook me up).

2. What type of material should i be using to make the can. Aluminum, tin, ect.

3. Were do i get headers that rap around like that and are really short. I need to find one.

4. Finally, were do i get the actual material for the exit pipe? I can't seem to find any thin metals



Thanks
Cameron
1) You can braze with a propane torch set that can be purchased at any Home Depot / Lowe's, etc. It's a great excuse to buy more tools and they are handy to have around for lots of things.

2) Aluminum is nice and light, but harder to find in the right wall thickness and container size. The aluminum Bud beer bottles work quite well and are available. Good excuse to drink more beer, too! Steel is quieter (the denser material transmits less sound through the walls of the can) and as Dick says, you can use paint cans as a source for containers. Bob Pastorello has a tutorial on building a muffler using the steel cans:

http://www.rcaerobats.net/

3) Mac's maybe or Karl Mueller will custom make anything you want for a pretty reasonable price with exceptional quality and workmanship.

4) Dick covered this one. You can also look for local steel suppliers in the yellow pages or online. I use Metals Supermarket here, but there are others around if you look.


Mark
Old 06-10-2008, 03:26 PM
  #60  
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Default RE: Need to quiet down my DL 50

Hi everyone, so one of my friends dad owns a big machine shop here in phoenix. I gave him a call and i think he will be able to weld this for me. I accidently baught some aluminum tubing for the inlet and outlet but now realize that those can't be welded to steal. So, i am going to have to find a steal thin material for welding. I ended up with 2 4oz paint cans. 2 7oz will just not fit in the plane. After venting them i began the procedure to set up the baffling and such. I really think this will work well.

After all the welding and such is done I am going to give Mueller call
Old 06-10-2008, 03:31 PM
  #61  
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Default RE: Need to quiet down my DL 50

I just tried the link and it worked perfect.Maybe its your browser.Its just the older AirHobbies,who was aero-sports,then they are now those people.
Old 06-10-2008, 10:01 PM
  #62  
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Default RE: Need to quiet down my DL 50

Change of plans. I am going to be using the beer bottle aproach because i found a source. Not sure how I will mount it. Probabley under the plane outside of the fuse. Might look cool. Still brainstorming.
Old 06-11-2008, 12:59 AM
  #63  
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Default RE: Need to quiet down my DL 50

Go look at the thread about building them.I think altavillan shows the bottom of his plane or somone else but theres pics there.Theres even a glow engine with a bottle underneath it.
Old 06-13-2008, 09:59 AM
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Default RE: Need to quiet down my DL 50

Okay, so my beer bottle muffler should be welded and finished by monday. I have started to look at headers. I am going to be placing this right under the fuse. I am assuming drop is the distance between the exhaust port and the inlet for the muffler? Is this correct? I am not sure if i need this thing custom made or not.

Cameron
Old 06-13-2008, 10:20 AM
  #65  
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Default RE: Need to quiet down my DL 50

Yes. Have a drawing ready to fax showing the drop from the engine ehaust port and center of the muffler inlet. Also the distance from the engine center line to the exhaust inlet. Then Call> http://www.macspro.com/ or some one and be ready to fax the paper if needed.
Also you can get all the parts to make up your own from> http://www.aircraftinternational.com/ including the silver solder. 3W's angled header flange will help start the exhaust down to the muffler and should be adjustable to fit your's or almost any engine. For straight shots the BME flange can be redrilled to fit your engines bolt pattern.
Old 06-13-2008, 10:21 AM
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Default RE: Need to quiet down my DL 50

correct
Old 06-13-2008, 11:18 AM
  #67  
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Default RE: Need to quiet down my DL 50

Cambo I don't know if you already seen this, but someone posted some photo's of a beer can setup in the galleries. Here is the link.

http://www.rcuniverse.com/gallery/ga...?itemid=144362

Edit: I'll try to link to his gallery.

http://www.rcuniverse.com/gallery/ga...emberId=121735


Old 06-13-2008, 12:07 PM
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Default RE: Need to quiet down my DL 50

Great, thanks everyone, that cleared it up.

I have been in contact with Karl Mueller who I am told does great work. The drop of all the comerciall avaible stuff is not enough. I am going to need something in the range of 4-5 drop rather than 2

Super08, I was looking at his setup. I set my muffler up slightly different. Closer to what a canister looks like.

Cameron
Old 06-13-2008, 12:30 PM
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Default RE: Need to quiet down my DL 50

ORIGINAL: pe reivers
This will severely reduce the available power. it is a system I use when I don't have much time (most of the time), and I can spare to wring in a few extra cubic inches to compensate for the stupid approach.

[/quote]

PE, I wish people like you could get points for rudeness and banned from the site after 100 points. You would have been gone a long time ago. I don't like seeing people being rude to other people who come on this site to enjoy themselves. You ruin it !!!

[/quote]

Joe

Just to mediate a bit, if you read Pe's quote above again you may realise he was being rude to no one but himself, after all is said and done English is not Pe's first language I just wished I could communicate in Norwegian as well as Pe does in English, a little bit of slack may be appropriate.

Mike
Old 06-13-2008, 01:20 PM
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Default RE: Need to quiet down my DL 50

BALDEAGEL:- Yes more a language problem than an intended insult. I took umbrage too

PE REIVERS:- 'Stupid' mainly refers to people not things. An incorrect choice of word [sm=thumbs_down.gif]
Old 06-13-2008, 02:02 PM
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Default RE: Need to quiet down my DL 50


ORIGINAL: BaldEagel

ORIGINAL: pe reivers
This will severely reduce the available power. it is a system I use when I don't have much time (most of the time), and I can spare to wring in a few extra cubic inches to compensate for the stupid approach.
PE, I wish people like you could get points for rudeness and banned from the site after 100 points. You would have been gone a long time ago. I don't like seeing people being rude to other people who come on this site to enjoy themselves. You ruin it !!!

[/quote]

Joe

Just to mediate a bit, if you read Pe's quote above again you may realise he was being rude to no one but himself, after all is said and done English is not Pe's first language I just wished I could communicate in Norwegian as well as Pe does in English, a little bit of slack may be appropriate.

Mike
[/quote]
Pe is now officially from Norway My Great Grandmother was from Jutland - and she also spoke Norwegian
strange
Old 06-13-2008, 03:28 PM
  #72  
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Default RE: Need to quiet down my DL 50

Hey! This "stupid" thing is going out of its proportions! Someone is touchy, others not... I actually also speak Norwegian. The ones that come from Jutland speaks Danish! but I'm not offended... This is ruining a very good thread about silencing those noisy gassers.

I'm also having a "noisy" 52cc gasser, and looking at good solutions to eliminate this problem. I've ordered a tuned pipe, actually designed for my 120AX, but I will test it on my gasser, just to see what will happen. If it reduces noise, then i can live with it. But I was actually hoping for a slight power increase. Based on what I have been reading, the shape and volume of the silencer is not crucial. It's the header length and backpressure that's matters.
Old 06-13-2008, 04:06 PM
  #73  
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Default RE: Need to quiet down my DL 50

Holland, where I live, is much more to the south I believe!
I do speak some Swedish, some Danish, and some norwegian, But Juttish not a single word!

@ dogshome:
Thanks for the comment.
If stupid is linked to people and not to approaches, I appologise to all that were offended by my wording. I humbly ask for proposals to rephrase my intent in the proper english language. I will then edit the original post.
I will however still take offence by one particular post, and demand he will appologise to me in DUTCH!
Old 06-13-2008, 04:09 PM
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Default RE: Need to quiet down my DL 50

Just FYI, i used the setup from this thread
http://www.rcuniverse.com/forum/m_47...tm.htm#4777330

I seems to me like it would quiet the plane down a bit more than the beer bottle muffler thread ideas. The reason is it has close to 1/2 more volume that a single bottle and the exhaust has to completely change drirection and and go through a baffle before it exits. Can't wait to try it.

Cameron
Old 06-13-2008, 04:14 PM
  #75  
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Default RE: Need to quiet down my DL 50

I have tried to use aerosols and pop (beer) cans, but found they did not last all that long. The thin walls also propagate a lot of noise.
Butane or propane tanks are much better suited, and so are oil filter housings! Any garage will have a collection in their dustbins. There is a weight penalty, but that will be offset by the results in sound attenuation and power gain.

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