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  #1  
Old 03-28-2021, 06:39 PM
Pilot8 Pilot8 is offline
 
Join Date: Sep 2018
Location: California
Posts: 78
Default RV8 cooling ramp cracks

Any RV8's out there with the 0.025" thick cooling ramp that has cracked? Getting ready to fix my 0.020" cracked ramp- checking to see if 0.025 is a winner.
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  #2  
Old 03-29-2021, 05:37 AM
phapp phapp is offline
 
Join Date: Mar 2008
Location: Walpole, NH
Posts: 58
Default Turn Downs

For those who answer please include whether you had the exhaust turn-down kit from Vetterman.
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  #3  
Old 03-29-2021, 07:37 AM
jbDC9 jbDC9 is offline
 
Join Date: Jan 2005
Location: Houston, TX
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Default

I donít know the ramp skin gauge on my -8, itís whatever was standard on a 2004 vintage QB kit... I had multiple ramp cracks within the first hundred hours running a 4 into 1 exhaust pipe with no downturned tip. I stop drilled the cracks, laid patches over the top, then installed a downturned exhaust tip. No more cracks at 1800 hours.
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  #4  
Old 03-29-2021, 09:50 AM
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Ironflight Ironflight is offline
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Join Date: Jan 2005
Location: Dayton, NV
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Default

Quote:
Originally Posted by jbDC9 View Post
I donít know the ramp skin gauge on my -8, itís whatever was standard on a 2004 vintage QB kit... I had multiple ramp cracks within the first hundred hours running a 4 into 1 exhaust pipe with no downturned tip. I stop drilled the cracks, laid patches over the top, then installed a downturned exhaust tip. No more cracks at 1800 hours.
Ditto all that for me, except that I have the standard four-in-to-two cross-over exhaust. The stop-drilled cracks have been there now for fifteen years, and my thought is that the down-turned tips ďfixedĒ the problem of beating up the skin.... yet I am but a single data point blowing in the exhaust stream.....
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  #5  
Old 03-29-2021, 10:37 AM
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Carl Froehlich Carl Froehlich is offline
 
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Location: Dogwood Airpark (VA42)
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Default

For those still building, consider replacing the provided aluminum cooling ramp with 0.015” SS. This also complements firewalls insulated with Fiberfrax and a thin SS clad.

Use the provided aluminum cooling ramp as a template to fabricate this SS replacement. It only takes a few minutes to get the curved front end just right.



Carl

Last edited by Carl Froehlich : 03-29-2021 at 11:04 AM.
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  #6  
Old 03-29-2021, 10:53 AM
scsmith scsmith is offline
 
Join Date: Jan 2008
Location: Ashland, OR
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Quote:
Originally Posted by Carl Froehlich View Post
For those still building, consider replacing the provided aluminum cooling ramp with 0.15” SS. This also complements firewalls insulated with Fiberfrax and a thin SS clad.

Use the provided aluminum cooling ramp as a template to fabricate this SS replacement. It only takes a few minutes to get the curved front end just right.



Carl
Plus one on making a stainless steel ramp. Carl meant 0.015”.

As a datapoint, I have a vetterman crossover exhaust with downturns.( or should I say turn-downs? ) I pop-riveted external stiffeners to the stock ramp (0.020) when built. Still got a couple of cracks.
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Last edited by scsmith : 03-29-2021 at 10:55 AM.
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  #7  
Old 03-29-2021, 11:12 AM
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fl-mike fl-mike is offline
 
Join Date: Jul 2005
Posts: 1,511
Default

Quote:
Originally Posted by Carl Froehlich View Post
For those still building, consider replacing the provided aluminum cooling ramp with 0.015Ē SS. This also complements firewalls insulated with Fiberfrax and a thin SS clad.

Use the provided aluminum cooling ramp as a template to fabricate this SS replacement. It only takes a few minutes to get the curved front end just right.

Carl
That's what I did. Flatten the provided ramp to make the template for a stainless version. I also put some Dynamat on the inside to dampen any drumming.
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  #8  
Old 03-29-2021, 04:09 PM
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DanH DanH is offline
 
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Location: 08A
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One piece, and while you're at it, get rid of the useless hinge.
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  #9  
Old 03-29-2021, 07:02 PM
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fl-mike fl-mike is offline
 
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The newer kits donít have the hinge. Not sure when the change happened.
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  #10  
Old 04-05-2021, 09:03 PM
Berchmans Berchmans is offline
 
Join Date: Nov 2009
Location: Anchorage, Alaska
Posts: 464
Default Cracking

I have a 2011 vintage fuselage kit, YIO360M1B, Vetterman 4 into 2 exhaust with turn down tips...plane flying since 2013 with 250 hours TT so far...no cracks. Another data point
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