Canard Community Forum  

Go Back   Canard Community Forum > Firewall Backward and Forward
FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
  #1  
Old 09-25-2006, 12:13 PM
Dust's Avatar
Dust Dust is offline
Super Moderator
 
Join Date: Apr 2004
Location: Troy, Michigan
Posts: 7,963
Default Exhaust breaking

Buly, could you describe the exhaust failure - did a weld let go?
__________________
Enjoy the build,njut av byggandet, godere il costruire, nyd bygningen, geniesse den Bau, apolafse tin kataskevi, disfrute la construcción, curta a construção, Pidä hauskaa rakentamisen parissa, bouw lekker,uživaj grade?inaslajdaites postroikoi, geniet die bou
dust

maker of wood, fiberglass, foam dust, metal bits and one day a Cozy will pop out and swiftly whisk me from meeting old friends and family to adventures throughout the world
Reply With Quote
  #2  
Old 09-25-2006, 01:20 PM
Buly Buly is offline
Buly
 
Join Date: Dec 2005
Location: FLORIDA, USA
Posts: 213
Default Exhaust

Quote:
Originally Posted by Dust
Buly, could you describe the exhaust failure - did a weld let go?
Welds started cracking and two of them gave out completely after 2 hours.
The rotary has very high rate of exhaust pulses unlike piston engine. Also the exhaust pulses are very sharp and powerful. The whole system was 2 pipes joining into one oval tail piece 3-4" long.
I think the problem was the whole system was weded solid and had no room for expansion. The material was 0.049 and could have been supported better.
My next one (in the shop right now) will have slip joints, muffler can, minimum number of welds, 0.065 wall, 321 SS material for the main headers and supported much better. Hope it lasts longer
Reply With Quote
  #3  
Old 09-25-2006, 01:27 PM
Dust's Avatar
Dust Dust is offline
Super Moderator
 
Join Date: Apr 2004
Location: Troy, Michigan
Posts: 7,963
Default

Quote:
Originally Posted by Buly
My next one (in the shop right now) will have slip joints, muffler can, minimum number of welds, 0.065 wall, 321 SS material for the main headers and supported much better. Hope it lasts longer

Slip joints are the key, 321 moves a lot with heat, I have double slips on my collectors.

support, mmm, needs to be only to the engine, doesn't it?

did it trash the prop

can you safety wire in case of future breakage
__________________
Enjoy the build,njut av byggandet, godere il costruire, nyd bygningen, geniesse den Bau, apolafse tin kataskevi, disfrute la construcción, curta a construção, Pidä hauskaa rakentamisen parissa, bouw lekker,uživaj grade?inaslajdaites postroikoi, geniet die bou
dust

maker of wood, fiberglass, foam dust, metal bits and one day a Cozy will pop out and swiftly whisk me from meeting old friends and family to adventures throughout the world
Reply With Quote
  #4  
Old 09-25-2006, 01:48 PM
Buly Buly is offline
Buly
 
Join Date: Dec 2005
Location: FLORIDA, USA
Posts: 213
Default

Quote:
Originally Posted by Dust
Slip joints are the key, 321 moves a lot with heat, I have double slips on my collectors.

support, mmm, needs to be only to the engine, doesn't it?

did it trash the prop

can you safety wire in case of future breakage
Supported to the engine only.
Ivo prop took it at 2400 prop rpm and just one blade had one dime size dent. I sentthe blade to IVO and it cost me $ 35 to fix it.
Safety wire could have helped too. The biggest help was from the SS heat shields I had made. Do not use aluminum for that.
Reply With Quote
  #5  
Old 09-25-2006, 01:55 PM
Dust's Avatar
Dust Dust is offline
Super Moderator
 
Join Date: Apr 2004
Location: Troy, Michigan
Posts: 7,963
Default

Quote:
Originally Posted by Buly
The biggest help was from the SS heat shields I had made. Do not use aluminum for that.
Yeah - aluminum as a heat shield seems like a oxymoronic thing to do, seems to me that it is a heat sink, not a heat shield
__________________
Enjoy the build,njut av byggandet, godere il costruire, nyd bygningen, geniesse den Bau, apolafse tin kataskevi, disfrute la construcción, curta a construção, Pidä hauskaa rakentamisen parissa, bouw lekker,uživaj grade?inaslajdaites postroikoi, geniet die bou
dust

maker of wood, fiberglass, foam dust, metal bits and one day a Cozy will pop out and swiftly whisk me from meeting old friends and family to adventures throughout the world
Reply With Quote
  #6  
Old 09-25-2006, 04:55 PM
neverquit's Avatar
neverquit neverquit is offline
G.Norman
 
Join Date: Sep 2004
Location: Lathrup Village, MI
Posts: 1,481
Default

Sounds like you know what you're doing Buly. Probably a lot of heat from that turbo doesn't help. I used to work at a Tech Center that tested new exhaust designs. I remember seeing exhaust manifolds strech so much they'd shear off the threads of the bolts or leave thread imprints in the cast iron before they cracked. If you're in a fix I can refer you to someone there.
Reply With Quote
  #7  
Old 09-25-2006, 05:10 PM
Buly Buly is offline
Buly
 
Join Date: Dec 2005
Location: FLORIDA, USA
Posts: 213
Default

Quote:
Originally Posted by neverquit
If you're in a fix I can refer you to someone there.
I'm in a fix alright! I started work in a company that overhauls aircraft exhaust systems.
Reply With Quote
  #8  
Old 09-25-2006, 05:42 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
Member
 
Join Date: Dec 2004
Location: Canada
Posts: 578
Default

.065 wall 321 stainless should be the minimum used on any turbocharged engine. 304 will not last on the inlet side for long unless it is at least .125 thick.

Slip joints or bellows are also of great benefit if the pipes are long or heading in different directions. Never hang the turbo off tubular headers, it should have a solid support structure.

Cracking pipes are a big safety concern with turbocharged engines as these can quickly lead to an inflight fire. Be careful lads and don't skimp on the materials here, especially on fire breathing Wankels with their hot breath.
Reply With Quote
  #9  
Old 09-25-2006, 05:53 PM
Dust's Avatar
Dust Dust is offline
Super Moderator
 
Join Date: Apr 2004
Location: Troy, Michigan
Posts: 7,963
Default

I think Buly is currently N/A, (non turboed)
__________________
Enjoy the build,njut av byggandet, godere il costruire, nyd bygningen, geniesse den Bau, apolafse tin kataskevi, disfrute la construcción, curta a construção, Pidä hauskaa rakentamisen parissa, bouw lekker,uživaj grade?inaslajdaites postroikoi, geniet die bou
dust

maker of wood, fiberglass, foam dust, metal bits and one day a Cozy will pop out and swiftly whisk me from meeting old friends and family to adventures throughout the world
Reply With Quote
  #10  
Old 09-25-2006, 05:56 PM
neverquit's Avatar
neverquit neverquit is offline
G.Norman
 
Join Date: Sep 2004
Location: Lathrup Village, MI
Posts: 1,481
Default

Maybe I'm mistaken but it looks like one...

http://home.bellsouth.net/p/s/commun...eid=188045&ck=
Reply With Quote
  #11  
Old 09-25-2006, 06:37 PM
CBarber's Avatar
CBarber CBarber is offline
Member
 
Join Date: Apr 2004
Location: Houston, Texas
Posts: 802
Default

Quote:
Originally Posted by neverquit
Maybe I'm mistaken but it looks like one...

http://home.bellsouth.net/p/s/commun...eid=188045&ck=
True, but he has since removed it, if I understand correctly.

All the best,

Chris
__________________
Chris Barber
www.LoneStarVelocity.com
Houston, Texas
Reply With Quote
  #12  
Old 09-25-2006, 08:03 PM
Buly Buly is offline
Buly
 
Join Date: Dec 2005
Location: FLORIDA, USA
Posts: 213
Default

I removed the stock turbo after the first two flights. The boost was going out of control (50-60" MP). I'm lucky it did not blow the engine. That's why the exhaust. Here is the one that fell apart. It was a beauty, and people knew I was comming long before I showed on the radar screen. Most of the alligatores migrated to the west coast of FL.
Attached Thumbnails
Click image for larger version

Name:	exhaust06.jpg
Views:	28
Size:	82.8 KB
ID:	2883  
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 11:54 PM.


Powered by vBulletin® Version 3.6.7
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.