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  #1  
Old 10-04-2017, 05:18 PM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,304
Default RV14 Exhaust hanger

I am noticing a bit of vibration in the tunnel and side skins of the RV14. The aircraft is also a bit louder in the cockpit then I am used to.
When I installed the aft exhaust pipe hanger I wondered why such a solid metal arrangement had been used.
In the following picture you can see the stock hanger on the right side and the "rubber" isolator that I fabricated on the left. I made the hanger from automotive exhaust pipe hanger material. Both sides now have the modified hangars and I will test fly it tomorrow. I have never seen, on any equipment, such a rigid exhaust pipe hanger as was supplied by Vans' for the RV14. The new set up securely holds the pipe and I can not help but think it will help with both vibration and sound. I will report back

Finally something on the RV14 that looks like it was made by a homebuilder;-)


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Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger flying #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
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  #2  
Old 10-04-2017, 08:13 PM
VA Maule VA Maule is offline
 
Join Date: Apr 2016
Location: Bucking ham, Virginia
Posts: 52
Default

Really good looking riveting. On the rubber hanger strap I would use one on each side exhaust systems don't like to be rigid.
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  #3  
Old 10-04-2017, 10:02 PM
pilotkms pilotkms is offline
 
Join Date: Mar 2007
Location: WARNER ROBINS, GA
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I think u will be happy. I used the same rubber material for my RV7A rather than the slippery tube and hose fittings per plans. More solid retention but the same or better flex. Has worked fine for my first 30 hours of phase 1.
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  #4  
Old 10-04-2017, 10:42 PM
kgood kgood is offline
 
Join Date: Mar 2009
Location: Boulder City, NV
Posts: 150
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I did the same thing with the exhaust on my Diesel Sportsman. The rubber ended up getting brittle and melting. So i cut 3/4" x 2" strips from a silicone turbo hose, and they have worked flawlessly for over 400 hours. They have remained soft and flexible; still look like the day i installed them.

FWIW....

Kurt Goodfellow
RV9 / WAM diesel 570 hours
Sportsman / CD155 Diesel 440 hours
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  #5  
Old 10-05-2017, 06:46 AM
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DanH DanH is offline
 
Join Date: Oct 2005
Location: 08A
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The cable loop hangers in this photo have been bulletproof, 700 hrs so far. Credit where due; they came with the pipes.

https://awi-ami.com/

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  #6  
Old 10-05-2017, 08:01 AM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
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1st flight with new isolators on exhaust got rid of almost all tunnel vibrations. Sound is subjective but seemed a lot quieter at all rpms.
So far I am impressed with the difference. The stock isolators are not at all similar to Dan's cable mounts. I can see how his to work as they allow the pipe to move. More flight tests yet today but it this looks like a step in the right direction.
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Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger flying #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com

Last edited by Tom Martin : 10-05-2017 at 03:03 PM.
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  #7  
Old 10-05-2017, 09:25 AM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 7,048
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The stock exhaust installation uses links that act very similar to links in a chain and do allow for a lot of movement if they are installed per the plans (the bolts are not meant to be torqued up fully which would crush the nylon bearing inserts and prevent movement).

The prototypes haven't experienced a lot of vibration transfer from the exhaust.
Perhaps they were installed incorrectly or a dynamic prop balance is in order.

Noise level is subjective without using an actual sound meter. The noise level has been measured in the prototypes and was found to be on par with the other 2 seat RV's with similar engine size. This was done during the exhaust development while comparing the benefits of a muffler vs performance penalty.

On any of the four cyl RV's, when compared to an RV-10 (or Rocket) that uses a 6 cyl engine, the 6 cyl seems quieter because the exhaust note is toned down somewhat but the actual db level in the cockpit is not much different.

BTW, in your photo it looks like the aft part of your Y pipe is not centered. Either you never got it aligned properly or the slip joint on the left side has moved.
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Last edited by rvbuilder2002 : 10-05-2017 at 09:28 AM.
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  #8  
Old 10-05-2017, 12:06 PM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
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Scott
Yes you are correct the pipe has move a bit off centre, I will correct
that. Every aircraft is different. The supplied hangers were installed as per plans and the bolts not too tight. Sound is subjective but I am hearing Garmin altitude alerts today that I have not heard for the first 15 hours. Vibrations are noticeably less with none in the tunnel area and now only slight on forward side skins. It has gone from a noisy aircraft to one smooth and quiet. Again every aircraft is different but my out of pocket cost are $5 and one hour of labour. Hard to argue about someone else trying it and reporting back
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Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger flying #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com

Last edited by Tom Martin : 10-05-2017 at 03:12 PM.
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  #9  
Old 10-05-2017, 01:45 PM
GigAir GigAir is offline
 
Join Date: Apr 2013
Location: Gig Harbor, WA
Posts: 41
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Tom,
Not related to noise, but I too was having issues with my exhaust hangers, which I discussed with Vans. In response Vans published a short new video, found under the "Service Info and Revisions for the RV14" menu. Also there is a new exhaust installation step 8 in Section 48-02, both dated 9/12/17.

Congratulations on your beautiful aircraft!

Greg Novotny
RV-14a N14ZP
Tacoma Narrows Airport
Gig Harbor, WA
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  #10  
Old 10-05-2017, 03:09 PM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,304
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Thanks Greg. I checked out the plans and saw the video and I am not really sure what they are trying to demonstrate in the 3 sec shot? Perhaps my system did not download the sound file?
I will keep monitoring the current rubber isolators, 4.7 hours today and they show no signs of heat damage or any other issues.



Quote:
Originally Posted by GigAir View Post
Tom,
Not related to noise, but I too was having issues with my exhaust hangers, which I discussed with Vans. In response Vans published a short new video, found under the "Service Info and Revisions for the RV14" menu. Also there is a new exhaust installation step 8 in Section 48-02, both dated 9/12/17.

Congratulations on your beautiful aircraft!

Greg Novotny
RV-14a N14ZP
Tacoma Narrows Airport
Gig Harbor, WA
__________________
Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger flying #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
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