1) What are the advantages/disadvantages of crimped on lead outs vs wrapped. I have the correct hardware to do either but can't decide. I purchased copper wire from Brodak for wrapping but it seams a bit stiff and the diameter seems a bit to large and I couldn't get a tight wrap on my mock up piece. I have done the crimped version several times but would like to wrap the ones on my new plane.

2) I'm afraid it's going to come out to nose heavy to use the factory muffler. I have seen the little rectangle headers that seam to do nothing more than duct the exhaust outside the cowl, is this assumption correct? I have access to the mill at work and can make it if that all it is.

Thanks
David

1) Improperly done crimps can set up a stress riser in the cables, possibly causing failure. If you don't have a high quality crimper, then it's probably better to use the AMA style wrapping. I use some 28g brass wire from some picture framing supplies I had, seems to work fine.

Here's one nice how-to:
http://www.clstunt.com/htdocs/dcforu...ID1/11840.html

An another:
http://www.clstunt.com/htdocs/dcforu...ID1/10973.html

2) Du-Bro makes little extender stacks, and it wouldn't be hard to make one since you have a mill. Do you have muffler requirements where you fly? If you do, then you may need at least a tongue muffler.

What airplane/engine/muffler are you thinking about? It might be all right for balance, or the stock muffler might be lightened a bit (the mill, again).

Kelvin

Thanks Kelvin, I have framed up a Brodak since Christmas.

David

The Brodak Nobler looks good in them bare bones. What are you going to finish it with? Anyway as far as leadouts I still use the wrap method. I get my wrapping wire from MBS Model Supply. Which is Melvin Schuette in Topeka, Kansas. I am working with the crimp stuff on lesser machines with my own crimmper like Carl Shoupe shows. If you need more help let me know. -DOC

I wrap with beading wire from the craft section of WalMart. It comes in different colors and sizes. I have more faith in wraps than I do in my crimps, but I will often crimp leadouts. The thing you have to worry about is having a hard point where all the flexing happens.

Jim

Thanks guys, do you have any idea what the diameter of the wire you are using? Like I say, what I have seems a little large at .022". It may be that I need more practice.

jehold-I'm covering it in Monokote, I have a picture of a Geiseke Nobler from a book that I might somewhat duplicate the trim scheme, might try some carved wheel pants also. Oh yea, it's a Brodak Nobler, I left off some words from my previous post.

Thanks
David

David,

As far as the muffler, you may be referring to what is known as a tongue muffler. The end has many holes drilled in it to disperse the sound. It is not as quiet as a full-size muffler but it is a bit lighter.

George

David,
I hae always used the bare copper wire that Sig sells to wrap lines. It measures 0.013 inches in diameter. I don't doubt that you are having trouble with the 0.022".
Chuck

gcb- The tongue muffler sound exactly what I have seen, with the holes and all. Is the end suppose to be open or does it have holes in it too?

r8893- I will try some smaller wire, I assumed I would be getting exactly what I need because I got it from Brodak and it was labeled for wrapping lead outs.

Thanks again
David

David,
The tongue muffler is not open on the end. Only exit openings are the small holes drilled on the side.
Lee TGD

David, I will attempt to post a picture of a tongue muffler I just made/remade.
Lee TGD Yikes,,, I over loaded!!

That's what I need! I plan to start making one tomorrow, I'll post the results, with a picture of the new Nobler.

I finished my tougue muffler today, it fits like a glove! I also wrapped my leadouts this evening, not the neatest job in the world but it's good and solid. I used some brass wire from WalMart as Jim Thomerson suggested, it's .020" in diameter and much more pliable and it made a huge difference. I'm waiting for my new irons to come in tomorrow and I'll be ready to cover it.

Thanks for all your help.
David Thomas

David,
Next time you make a tongue muffler, keep the exit holes down in size to about 1/16". I have the correct hole size at work. The factory built one that I copied had 20 holes. I will post the correct size in the morning. Looks like you done a great job making your muffler.
Lee TGD

My buddy sent me a picture of his muffler and it had 10 holes that I would guess about .125" in diameter. I made 9 holes .160", I don't know why I did it this way, I just did what I thought looked right. I thought the only purpose was to get the exhaust out of the cowl and didn't think it mattered much about the holes. Anyway...I should have it about ready to fly this weekend but the weather looks pretty grim. I don't plan to test fly until a nice day but I'll let you know how it goes.

David

Hey David,
There is probably some rhyme and reason about the holes sizes. Far be it for me to have those answers. I was just a copy cat on that. I just shortened the one in the picture I posted earlier. It has less than 20 holes, but they are just a bit larger that in my store bought for 35/40 engines. Maybe if DOC or Bob Reeves reads this they can shed some light on the numbers. Let me know how it works and how quiet it is. Actually here at our field, we are not required to run the mufflers.
Lee TGD

David, I measured the holes in the store bought muffler, and they measured out at .0735 thousands.
Lee TGD

You can also put a pressure tap on and run muffler pressure to your fuel tank. The size/number of the holes has to do with how much back pressure the muffler gives. This can affect, for bad or good, how the engine runs. There is a lot of arm waving about this. It also affects the sound. One of the posts on another forum talked about making a lot of very tiny holes. Fly it, fool with it, and tell us what you think.

Jim

It's possible to fine tune the noise level and back pressure by plugging holes with 4/40 screws. I can't say that I've needed to do that, but I have seen it done. I suspect that a motor that was running away might be regulated by plugging holes.

All my OS 20s and 40s meet the 90dbA rule with tongue mufflers and aren't subjectively very noisy. We measure and log noise levels as part of our deal with the city for the flying site.

Might fly it tomorrow.

Hey, lookin good David. Let us know how it flys. Did you monocote the fuse, or is that painted?
Lee TGD

Didn't get to fly it this weekend, my only chance was today and it rained all day long, maybe next week?

fox4evr- The whole plane is covered in Monokote.

I was wondering what some of you are using for connectors from the eyelets on the handle and leadouts to the cables? I searched this on a couple of forums but no alternatives popped up. The line connectors I got from Tower in the ARF Streak bundle look very flimsy. I know about Sullivan slide connectors. Are there good substitutes or scratch built alternatives. Waiting on the weather...............

Rick

I use the Perfect slide connectors or the ones Brodak sells, they seem like exactly the same thing.

Do not and I repeat do not use the slide type connectors unless you like building airplanes. Go to mbsmodelsupply on the internet as Melvin has the scissor type that we use and recommend. He also has goodies for control line also. -DOC