VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
w/a Donation






VAF on Twitter:
@VansAirForceNet

  #1  
Old 05-16-2023, 05:11 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 6,851
Default ELT antenna

I mounted the "Yak" (ACK) ELT on a Vans mount per plans just behind the F706 baggage bulkhead. That was enough for the day. Dufficult job. Next up is the antenna. The manual says not to pass through any bulkheads.

Does that mean not to actually route the coax through a snap bushing or don't cross a bulkhead at all?

My 7A is a slider. The only place I can mount the antenna to comply with the DAR and Yak manual is centered top aft skin right in front of F708 bulkhead. That means passing F707. The F707 bulkhead is wide open. The coax can pass F707 without touching anything. Is that ok?

Should the coax be secured or just left hanging? If I tie it off, it could get severed in an accident.

I installed nutplates in all the locations on the mount for future use. So many builders have problems with the Yak, I will probably replace it. That mount is not coming out so hopefully the holes match other ELTs.
Click image for larger version

Name:	20230516_153519.jpg
Views:	87
Size:	171.1 KB
ID:	42519
__________________
Larry Larson
Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog: http://wirejockrv7a.blogspot.com
Donated 12/2022, plus a little extra.
RV-7A #73391, N511RV reserved
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
  #2  
Old 05-16-2023, 05:23 PM
terrye terrye is offline
 
Join Date: Feb 2010
Location: Vancouver, BC, Canada
Posts: 1,104
Default

My understanding is if the coax is routed through a bulkhead (whether a snap bushing or rubber grommet) it could get severed if the bulkhead deforms during a crash. So routing it around a bulkhead, and secured sufficiently, is preferrable.
__________________
Terry Edwards
RV-9A (Fuselage)
2023/2024 VAF Contribution Sent
Reply With Quote
  #3  
Old 05-16-2023, 05:27 PM
Mel's Avatar
Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
Posts: 11,941
Default

Quote:
Originally Posted by terrye View Post
My understanding is if the coax is routed through a bulkhead (whether a snap bushing or rubber grommet) it could get severed if the bulkhead deforms during a crash. So routing it around a bulkhead, and secured sufficiently, is preferrable.
What Terrye said.
__________________
Mel Asberry, DAR since the last century. Over 1,100 certifications accomplished. Discount for Veterans, Law Enforcement, Fire Fighters.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1, Lifetime EAA.
Recipient of EAA Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
Reply With Quote
  #4  
Old 05-16-2023, 05:42 PM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is offline
 
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 4,430
Default

If memory serves, this means that all RV-14s built per plans will not pass a DAR.

Carl
Reply With Quote
  #5  
Old 05-16-2023, 05:51 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 6,851
Default Route around

Quote:
Originally Posted by Mel View Post
What Terrye said.
Thanks Mel and Terry
Exactly what I needed.
__________________
Larry Larson
Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog: http://wirejockrv7a.blogspot.com
Donated 12/2022, plus a little extra.
RV-7A #73391, N511RV reserved
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
  #6  
Old 05-16-2023, 06:04 PM
Webb's Avatar
Webb Webb is offline
 
Join Date: Oct 2007
Location: Jackson, MS
Posts: 1,952
Default

What would be the preferred method of securing the coax when routing around a bulkhead?
__________________
Webb Willmott
KJVW
RV8 - Current Build
N414WW Reserved
V35B - Flying
RV7A - N32WW (Sold)
Reply With Quote
  #7  
Old 05-16-2023, 06:41 PM
Scott Hersha Scott Hersha is offline
 
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 2,761
Default

Getting around a bulkhead that is covered by a baggage bin cover panel that will also need some sort of hole drilled with a snap bushing or something similar, doesnít seem like it would alleviate the potential shearing of the antenna cable in a crash. To take the bulkhead question out of the equation, you would need to mount the antenna through the skin of the compartment the ELT is in - like through the top/side/bottom of the turtle area skin? What happens when you flip over or that tail cone skin is sacrificed? It doesnít seem like some non-standard installation would be worth the effort. Is there some data/information that the per plans installation hasnít worked?
__________________
SH
RV6 - Flying
Cincinnati, OH/KHAO
DEC2022
Reply With Quote
  #8  
Old 05-16-2023, 06:42 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 6,851
Default Securing cables

Quote:
Originally Posted by Webb View Post
What would be the preferred method of securing the coax when routing around a bulkhead?
I can't speak as an expert, but I hate zip ties with a passion. Not a single one on my airplane.
They hold great till they get brittle. New ones wouldn't release in an crash. Brittle ones just fall apart.
My plan is to leave service loops, aka crash loops secured with self fusing silicone tape. One near the antenna. One at the F707 bulkhead. One at the ELT. It holds very well and tears under pressure. Normally, I would put a tie of waxed lashing string, but that stuff will cut wire. Not a good idea.

If someone has another product, I'm listening.
__________________
Larry Larson
Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog: http://wirejockrv7a.blogspot.com
Donated 12/2022, plus a little extra.
RV-7A #73391, N511RV reserved
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
  #9  
Old 05-16-2023, 06:50 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 6,851
Default Bulkheads

Quote:
Originally Posted by Scott Hersha View Post
Getting around a bulkhead that is covered by a baggage bin cover panel that will also need some sort of hole drilled with a snap bushing or something similar, doesnít seem like it would alleviate the potential shearing of the antenna cable in a crash. To take the bulkhead question out of the equation, you would need to mount the antenna through the skin of the compartment the ELT is in - like through the top/side/bottom of the turtle area skin? What happens when you flip over or that tail cone skin is sacrificed? It doesnít seem like some non-standard installation would be worth the effort. Is there some data/information that the per plans installation hasnít worked?
I'm not passing coax through any bulkhead with a hole. The ELT is AFT of the baggage bulkhead per Vans on a Vans designed ELT mount. The only bulkhead the coax will pass is a huge open area. ELT and antenna are both aft of the fuse/tail cone seam. Antenna is recommended on top. Nothing I can do it if it goes wrong side up. Same problem if not worse to place it on the bottom or a side skin. Plans warn against placing it in wingtips or under fairings. It has to be a certain orientation from vertical.
Per Mel, DAR, it has to be installed per manual or be in violation.
Maybe I'm missing the point.
__________________
Larry Larson
Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog: http://wirejockrv7a.blogspot.com
Donated 12/2022, plus a little extra.
RV-7A #73391, N511RV reserved
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
  #10  
Old 05-16-2023, 07:03 PM
Webb's Avatar
Webb Webb is offline
 
Join Date: Oct 2007
Location: Jackson, MS
Posts: 1,952
Default

Maybe I’m being cynical but if a crash is sufficient to deform a rear bulkhead and severe a coax cable, then the forward compartment probably could be used for an aluminum coffin.

But to keep in the spirit of things, perhaps a loop in the coax between the bulkheads to provide the “slack” needed to prevent stretching and potential severing of the coax in the event of a crash.
__________________
Webb Willmott
KJVW
RV8 - Current Build
N414WW Reserved
V35B - Flying
RV7A - N32WW (Sold)
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 -6. The time now is 01:08 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.