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Exhaust routing


Edge 513

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No thought has been put into this what so-ever, but a thought pooped into my mind and I had to let it out.

 

Has anyone ever tried to transition the circular exhaust to a long thin rectangle? This way the exhaust stream is wider and thinner and should cool rapidly. Think of the long thin exhaust on the F117A to reduce the IR signiture.

 

This may be a solution to cooler exhaust temps at the prop (as well as more prop blade absorbing the same heat energy so less localised heating). Or this may be utter BS. Just a thoughty. The trick would be to keep the cross section area at the rectangle the same (or very slightly larger) as the circular exit to avoid any funny effects.

Adrian Smart

Cozy IV #1453

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Jack's having some PC problems. He's asked me to submit these for him....

 

 

 

Here is the broken exhaust and toasted lower cowl. Next is the fix. As always, great professional work.

 

...should I show more?

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Jack's having some PC problems. He's asked me to submit these for him....

 

 

 

Here is the broken exhaust and toasted lower cowl. Next is the fix. As always, great professional work.

 

...should I show more?

post-672-141090161822_thumb.jpg

post-672-141090161829_thumb.jpg

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Everybody builds to different levels. Some are just happy as clams to build a plane that flies and looks 'nice'...some take it to a work of art. Jacks game is so on...we should give him a Jerry West or Michael Jordon jersey with his Eracer silhouette printed on the back below the #'s....he's so at that level. This is a place where serious dough and serious talent meet marvelously.

Thanks for forwarding the pics.

Self confessed Wingnut.

Now think about it...wouldn't you rather LIVE your life, rather than watch someone else's, on Reality T.V.?

Get up off that couch!!! =)

 

Progress; Fuselage on all three, with outside and inside nearly complete. 8 inch extended nose. FHC done. Canard finished. ERacer wings done with blended winglets. IO540 starting rebuild. Mounting Spar. Starting strake ribs.

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  • 2 weeks later...

So, I'll tell the story as I understand it from Jannie Versfeld and Curt A Smith (ex USA) in ZU-DAR.

 

They were flying from FAMG (near the SA coast) to FALA. On flight plan (IIRC)

 

Jannie had the 3 into 1 pipes, these came out the single opening at the rear of the cowling.

 

The pipe broke at the last join - the tail piece vibrated somewhat & found its way out the cowling, taking a chunk out the prop as it left the plane.

 

The shorter exhaust did heat the cowling some, but I can't comment.

 

The chunk out the prop reduced the max RPM to about 1200 (IIRC) which allowed them to make their way from the Donnybrooke area (REAL hostile terrain) to FAPM, where they managed to organise the world from there ... :)

post-4196-141090161999_thumb.jpg

post-4196-141090162001_thumb.jpg

I live in my own little world! but its OK, they know me here!

Chris Van Hoof, Johannesburg, South Africa operate from FASY (Baragwanath)

Cozy Mk IV, ZU-CZZ, IO-360 (200hp) 70x80 prop

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Or maybe just move forward the single (or multiple) exhaust pipe with hot gases shooting 45degres downwards (see quick and dirty hand drawing attached)

This would let hot gases (here in red) cool up and mix with the cold free stream (in blue), and the air arriving on the prop would be cold if not cool enough...

post-8058-14109016201_thumb.jpg

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So, I'll tell the story as I understand it from Jannie Versfeld and Curt A Smith (ex USA) in ZU-DAR.

 

They were flying from FAMG (near the SA coast) to FALA. On flight plan (IIRC)

 

Jannie had the 3 into 1 pipes, these came out the single opening at the rear of the cowling.

 

The pipe broke at the last join - the tail piece vibrated somewhat & found its way out the cowling, taking a chunk out the prop as it left the plane.

 

The shorter exhaust did heat the cowling some, but I can't comment.

 

The chunk out the prop reduced the max RPM to about 1200 (IIRC) which allowed them to make their way from the Donnybrooke area (REAL hostile terrain) to FAPM, where they managed to organise the world from there ... :)

With no disrespect to Janie, I would kinda expect that exhaust system to fail. It has no slip joints to take up the expansion upon heating.

I think you gotta put slip joints (and maintain the movement (mouse milk) between areas so that the normal movement can take place without stressing the welds or they will crack and possibly leave the aircraft:mad: .

I Canardly contain myself!

Rich :D

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I also noticed that Rich. I have 3into one with slip joints between each cyl. Mine are also SS .062, very heavy but strong. In an earlier post when my right exhaust broke off, I had just changed the exhaust direction facing out to the side. It somehow set up a sonic pulse that broke the pipe in a matter of 15 minuets flying. That same pipe going straight back had been on the engine for 6 years without a failure. Also I consider myself a good welder but I had a professional welder in stainless and aluminum do the welding on the exhaust and my engine mount. You can never be too careful when it comes to securing items which could exit the rear and ruin your whole day and possibly much more. The sketch above in the previous reply is how Velocity exits their exhaust.

 

Jack

E Racer113

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And I might add to Jacks post that Velocities 3 pipe exit out the bottom on each side looks terrible aero-wise. Like the pipes sticking out the sides of the Munster-mobile...:bad:

Self confessed Wingnut.

Now think about it...wouldn't you rather LIVE your life, rather than watch someone else's, on Reality T.V.?

Get up off that couch!!! =)

 

Progress; Fuselage on all three, with outside and inside nearly complete. 8 inch extended nose. FHC done. Canard finished. ERacer wings done with blended winglets. IO540 starting rebuild. Mounting Spar. Starting strake ribs.

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With no disrespect to my friend Jannie either.

 

If you peruse the date on the picture (about 2003) of the exhausts and do a search in the Cozy archives, then you will notice that there was a discussion at that time regarding failures experienced in that type of set-up.

 

We did bring that to his attention (Gavin Lawson & myself), it was his choice to proceed with the design he had followed.

 

This does not make him a lesser friend, just a lucky one.:)

 

His new set-up looks like the attached photo.

post-4196-141090162016_thumb.jpg

post-4196-141090162018_thumb.jpg

I live in my own little world! but its OK, they know me here!

Chris Van Hoof, Johannesburg, South Africa operate from FASY (Baragwanath)

Cozy Mk IV, ZU-CZZ, IO-360 (200hp) 70x80 prop

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Just for grins- do you have a photo similar angle as the naked, cowl off photo- but with the cowl on? Theres a trailing opening in the cowl that is barely shown in the left pic- that I would like to see. I think it is exiting the airflow from the oilcooler on the engine aft boottom? I wonder if he is liking that setup? This lower cowl looks a little bit diff than the one a few posts before. How is his prop taking the exhaust from this vertical stacking? It looks great. Is he liking it?

While at Columbia Fly-in- I was looking at a V8 exhaust that had 4 per side in the trailing edge. I wondered how the owner liked that choice. They were all welded together within a few inches of the openings. I wondered about cracking. Looked very aero- sitting in the trailing edge. I liked that.

Self confessed Wingnut.

Now think about it...wouldn't you rather LIVE your life, rather than watch someone else's, on Reality T.V.?

Get up off that couch!!! =)

 

Progress; Fuselage on all three, with outside and inside nearly complete. 8 inch extended nose. FHC done. Canard finished. ERacer wings done with blended winglets. IO540 starting rebuild. Mounting Spar. Starting strake ribs.

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Edge,

 

if you are talking about jannie's set-up?

 

The LH picwas after he had fixed & done cosmetics.

 

The RH pics of the pipes was while he was fixing on the away site ...

 

I hear the English, but the actual meaning escapes me!

 

Jannie is doing his annual inspection this week, so the cowlings are off and I can go take any photo you want ... now what was your question?

 

Regards

 

Chris Van Hoof

I live in my own little world! but its OK, they know me here!

Chris Van Hoof, Johannesburg, South Africa operate from FASY (Baragwanath)

Cozy Mk IV, ZU-CZZ, IO-360 (200hp) 70x80 prop

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I have pointed Jannie to this thread, maybe he'll visit & give his own opinion :)

 

Don't have better picture, we all rushed out to help, so the camera batteries went etc ... and I had to deal with my Softness, sitting there complaining about being surrounded by Cozy Builders and she had to fly them around the country in her Cherokee 6 :) But I do love her!

 

Yes, the cowling is different, he is an extremely fast worker and thinks nothing of changing things (one way, the other way and back) in the time it takes me to type this ... he does not move, he hyperspaces! You simply have to see it, but don't blink! :)

 

IIRC he did report better cooling!

I live in my own little world! but its OK, they know me here!

Chris Van Hoof, Johannesburg, South Africa operate from FASY (Baragwanath)

Cozy Mk IV, ZU-CZZ, IO-360 (200hp) 70x80 prop

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Thanks ZUCZZ. Great pic with the cowl off. Got That there.

Just was looking for a pic from same angle- with the cowling on.

Thanks for your willingness to help.:)

Self confessed Wingnut.

Now think about it...wouldn't you rather LIVE your life, rather than watch someone else's, on Reality T.V.?

Get up off that couch!!! =)

 

Progress; Fuselage on all three, with outside and inside nearly complete. 8 inch extended nose. FHC done. Canard finished. ERacer wings done with blended winglets. IO540 starting rebuild. Mounting Spar. Starting strake ribs.

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Just for grins- do you have a photo similar angle as the naked, cowl off photo- but with the cowl on? Theres a trailing opening in the cowl that is barely shown in the left pic- that I would like to see. I think it is exiting the airflow from the oilcooler on the engine aft boottom? I wonder if he is liking that setup? This lower cowl looks a little bit diff than the one a few posts before. How is his prop taking the exhaust from this vertical stacking? It looks great. Is he liking it?

While at Columbia Fly-in- I was looking at a V8 exhaust that had 4 per side in the trailing edge. I wondered how the owner liked that choice. They were all welded together within a few inches of the openings. I wondered about cracking. Looked very aero- sitting in the trailing edge. I liked that.

If they are welded together, there will probably be cracking. Each stack is a different length and each will expand and contract (lengthwise) in an amount proportional to its individual length.

 

If allowances are not made for the stacks to exercise this right of expansion, it's cracksville:sad:

I Canardly contain myself!

Rich :D

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Hi all,

 

Here is a link to my Cozy WEB. http://www.cozysa.estart.org.za/cozy.htm

 

There are many pictures showing the cowling from different angles and inflight pics.

 

My exhaust is from Custom Aircraft Parts and they specifically designed and built it for me in a matter of 10 days delivered. Kudos to them.

 

I immediately noticed lower CHT's after the installation. The exhausts have slip joints and a safety strap where they are stacked. I tried to keep to the general Cozy cowl aesthetics as best as possible. At least this setup will containg a broken pipe should it happen, but I think the system is very vibration friendly. I have only about 25 hrs on the new exhaust at this stage so I cant comment on longevity yet.

 

Jannie Versfeld

Cozy MKIV O540

South Africa

http://www.cozysa.estart.org.za/cozy.htm

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Thanks for clearing that up Jannie!

 

Checked out your new site while I was at it ... forgot anout your brilliant fuel cap thinghy :)

I live in my own little world! but its OK, they know me here!

Chris Van Hoof, Johannesburg, South Africa operate from FASY (Baragwanath)

Cozy Mk IV, ZU-CZZ, IO-360 (200hp) 70x80 prop

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Heres the picture of the exhausts in the trailing edge, I was referring to from the Columbia fly-in. Can't remember these folks names.

post-4661-141090162055_thumb.jpg

Self confessed Wingnut.

Now think about it...wouldn't you rather LIVE your life, rather than watch someone else's, on Reality T.V.?

Get up off that couch!!! =)

 

Progress; Fuselage on all three, with outside and inside nearly complete. 8 inch extended nose. FHC done. Canard finished. ERacer wings done with blended winglets. IO540 starting rebuild. Mounting Spar. Starting strake ribs.

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From my uneducated view- this looks very very very nice. Just incredible! Great photo angle.

Self confessed Wingnut.

Now think about it...wouldn't you rather LIVE your life, rather than watch someone else's, on Reality T.V.?

Get up off that couch!!! =)

 

Progress; Fuselage on all three, with outside and inside nearly complete. 8 inch extended nose. FHC done. Canard finished. ERacer wings done with blended winglets. IO540 starting rebuild. Mounting Spar. Starting strake ribs.

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Folks, Jannie's plane looks even better in real life than on these photos!

I live in my own little world! but its OK, they know me here!

Chris Van Hoof, Johannesburg, South Africa operate from FASY (Baragwanath)

Cozy Mk IV, ZU-CZZ, IO-360 (200hp) 70x80 prop

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