New Exhaust

[weasel]

I been working on a new exhaust system for the Classic in an effort to prepare for making a cowling.

Keeping it light is hard.

I made the first sections from 1-1/4" .049 steel then transitioned to Brass 1-1/4" .028 brass drain tubing.

It may or may not hold up...we will see.

[PropMan]

Hey Weasel,
I cant see the pics, sure would like a play by play. Want to do this for the 4A084.

[weasel]

Can you see them now Frank?

I wanted to use 1-1/4" .035 wall for the first 4-6 inches of each stack but I cant find .035 wall stock that has mandrel bends.

Got any connections that will supply any? or better yet .028 wall mandrel bend steel or stainless

[PropMan]

Yeah,  looks good. Sorry no contacts. Keep the photos coming.

hey, I like how you slipped the prop in the pic. Thanks

[Steve]

Try Jack Burns @ BurnsStainless.com for a special order or referral to another vendor...

[docmatt]

Looks good!  When the time comes, I may look for titanium.  I wonder if it is available with the right bends?  Does anyone have thoughts about the pros and cons of directing the exhaust up instead of down, to decrease the noise heard from the ground?

[scottiniowa]

Looks good!  When the time comes, I may look for titanium.  I wonder if it is available with the right bends?  Does anyone have thoughts about the pros and cons of directing the exhaust up instead of down, to decrease the noise heard from the ground?

Ti, cost  might scare you, and if you using the rule, of $100 per pound of weight savings as max, you might have again a hard time to justify. And of the 5 alloys, I am not sure which you would need. Pure would be to soft and Grade 5 perhaps to hard.  Bending is very hard to do, do to the memory of it. (what looks good today, might not tomorrow)

I’m not sure what the “right bends” would be that your thinking about, but generally affordable tubing with bends already done, is bent tubing that works for exhaust but already made up for another commercial purpose.  i.e. stainless banister or hand rails.

Directing tubes up, brings the NOISE to you…and we sure don’t want that…Consider all the engines of far higher power with NO exhaust, yours will be far less noisy and not as much of a concern.

Best of success.

[Tom H]

I can relate to the exhaust noise issue.  DE Stubby has four separate cheap steel pipes from each exhaust port, each 12 to 18 in long, angled down and to the rear.  A very common comment from observers of the airplane flying is "it is loud - but sounds great!"

(An aside: I'd like to insert a picture, but the box opens and asks for a URL, starting with http:...    What does it want, how do you insert pictures??)

Back to exhaust - I was helping a friend get his Sonex GP 2180 engine running, and was amazed at how quiet it was.  It had two-into-one pipes on each side.  Can't remember the exact configuration or lengths, but it did not have any mufflers.

We started talking out loud about looking into changing over to that configuration.

I don't know why it is quieter, and don't know if it helps or hurts the engine power.  Anybody know?

[Bob S.]

An aside: I'd like to insert a picture, but the box opens and asks for a URL, starting with http:... What does it want, how do you insert pictures?

You have to have the picture located on a website somewhere....

[Steve]

An aside: I'd like to insert a picture, but the box opens and asks for a URL, starting with http:... What does it want, how do you insert pictures?

You have to have the picture located on a website somewhere....

Bob S:
You have Forum Gallery rights - if you look at my Gallery you will see a Sub Category of pic's I embedd in Posts -ie your Gallery url's are a place on the Web...
Steve

[Dan_]

An aside: I'd like to insert a picture, but the box opens and asks for a URL, starting with http:... What does it want, how do you insert pictures?

You have to have the picture located on a website somewhere....

Bob,
Just hit "attachments and other options" at the bottom of the post box...  You can then navigate to a pic on your computer and send it.  It shows up as a rather large thumbnail which can be clicked on to see in 1027X768.  No need to reduce high resolution pics, they are automatically reduced to 1027X768 or if smaller... remain at their native res.  If you click the hypertext link below the attached pic you can download and save to your computer...

[docmatt]

Ti, cost  might scare you

Sometimes surplus stuff turns up on E bay.  Might be worth watching for it.

I’m not sure what the “right bends” would be that your thinking about, but generally affordable tubing with bends already done, is bent tubing that works for exhaust but already made up for another commercial purpose.  i.e. stainless banister or hand rails.

I've seen steel "donuts" of different sizes, intended to be cut and welded for exhausts.  Don't know about Ti though.

Consider all the engines of far higher power with NO exhaust, yours will be far less noisy and not as much of a concern.

You are right, low powered planes often have more prop noise than engine noise.   Still, I may experiment with light weight, possibly consumable, mufflers.  I'd really like cabin heat too, so maybe combine that with a muffler.  On the other hand, heated clothing would probably be simpler and lighter.  
Sorry for the thread creep.  Maybe should start a new one.

[Tom H]

Ok, trying to follow Dan's instructions to attach a pic from my computer.  If successful, the pic should show DE Stubby's exhaust pipes.

[Dan_]

Ok, trying to follow Dan's instructions to attach a pic from my computer.  If successful, the pic should show DE Stubby's exhaust pipes.

Works like a charm...

To do what Bob and Steve were talking about you reference a URL on the net by clicking the pic icon in the post editor.  This could be a location in your Google "Picassa" account, Flickr, cloud storage or any web page... 

[scottiniowa]

Doc, I don’t think you have taken your thread to far off the beaten path and I would like to elaborate a bit more on some of your thoughts.

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Ti, cost  might scare you

Sometimes surplus stuff turns up on E bay.  Might be worth watching for it.
  While this is true in the fact that things may show up, I have found that on Ebay, often Ti is listed but a grade is not or is listed incorrectly. Both bad.  Just be aware of what you may be getting.  Presently of the 5 grades, I would do a bit of research to determine which would be best for this.  I’m not aware of any commercial offered pipes for any aircraft that are such. I presume this is for more than just a cost factor..would be worth checking out.

Quote

I’m not sure what the “right bends” would be that your thinking about, but generally affordable tubing with bends already done, is bent tubing that works for exhaust but already made up for another commercial purpose.  i.e. stainless banister or hand rails.

I've seen steel "donuts" of different sizes, intended to be cut and welded for exhausts.  Don't know about Ti though.
Certainly could be out there, but knowing that Ti needs to be carefully T I G welded, with back purge and air excluded box with the Ti fill rod, this knocks it out for many reasons (most are not set up for this) So if you add a curve from the standard donut piece you have added two additional welds plus the flange and attach brackets.  You really shouldn’t weld in open air like you would do stainless or common steels with your T I G set up.

Quote

Consider all the engines of far higher power with NO exhaust, yours will be far less noisy and not as much of a concern.

You are right, low powered planes often have more prop noise than engine noise.   Still, I may experiment with light weight, possibly consumable, mufflers.  I'd really like cabin heat too, so maybe combine that with a muffler.  On the other hand, heated clothing would probably be simpler and lighter.   
     Excellent comment, as heated clothing has really come along… with nearly all having a “heating time” lasting longer than your fuel capacity, even if on high.  The pants may be harder to come by, but the coats/socks are really out there. And use standard cordless batteries like Dewalt/Milwaukee (if you can call any of these standard)  And like you say, simpler by far if needed just a few times per year.  Weight wise, it may be a trade off,  but colder temps, equal more performance and it could keep the line pretty level. Good thoughts Doc.