ELT Antenna Placement

A forum in which to discuss topics specific to the assembly of the RV 8/8A
clreding
Class E
Posts: 117
Joined: Mon Jun 18, 2007 4:09 pm

ELT Antenna Placement

Postby clreding » Sat Aug 13, 2016 2:49 pm

Question for all of those guys who have built an RV-8
I know a lot of people place their antennas horizontally under the fairing for the horizontal stabilizer. Im not a big fan of doing it that way for my own reasons.
I am thinking of placing my ELT antenna on the upper skin passing through the fairing just behind the canopy when its fully open. I added a picture in the Gallery of my planned location (I can't seem to get the picture here :) )
I understand that it will be a bear removing the antenna if I ever needed to replace it but is there any other reason NOT to mount it here that any of you can see?

Thanks for the input

User avatar
bruceh
Class D
Posts: 361
Joined: Sun Apr 06, 2008 11:11 pm
Location: Ramona, CA
Contact:

Re: ELT Antenna Placement

Postby bruceh » Sat Aug 13, 2016 4:18 pm

The ELT may just save a live. Maybe yours? Why not just follow the manufacturer's recommendations for where to mount it (like on the outside of the fuselage)?
Bruce Hill
RV-9A N5771H flying over 700 hours!
http://www.overthehills.com/RV-9A-Project
APRS Tracking: http://aprs.fi/#!mt=roadmap&z=11&call=a ... tail=21600
EAA Tech Counselor

User avatar
bullojm1
Chief Rivet Banger
Posts: 1317
Joined: Sat Mar 25, 2006 6:37 pm
Location: KDMW
Contact:

Re: ELT Antenna Placement

Postby bullojm1 » Sun Aug 14, 2016 6:40 am

Craig,

Here is the picture you were trying to post. Apologies for the Gallery being so cludgey - it is a left over artifact from the previous owner of RB. I keep it around just to make sure the picture links still work from previous posts. I suggest using PhotoBucket to post pictures in. It's a fantastic product.

Image

While I don't have a RV-8, I'd be concerned with putting the ELT antenna so close to the vertical stabilizer. I could see in an accident, either the antenna bending backwards and grounding itself against the VS, or vice versa. Is there not any room on the top of the fuselage between the aft end of where the canopy is when open and the vertical stabilizer?
Mike Bullock
http://www.rvplane.com
RV-7 | Superior IO-360 | Whirlwind 200RV
Garmin GTN650 | GRT Dual Sport SX EFIS
Status: FLYING!

clreding
Class E
Posts: 117
Joined: Mon Jun 18, 2007 4:09 pm

Re: ELT Antenna Placement

Postby clreding » Sun Aug 14, 2016 7:52 am

Mike
Thanks for posting the pic. Unfortunately all antenna mounting on the 8 is a compromise of one kind or another. The sliding canopy covers virtually all of the upper skin between open and closed positions. the purple fiberglass in the picture is the rear fairing of the canopy The yellow fiberglass is the front fairing of the VS.
The only other place I can see to mount this to meet my requirements is in the same basic location but at an angle (up to 30 degrees left or right) but since this is a taildragger i would be concerned that someone would get a poke in the eye.... not good
For my purposes, technically I think this is the best "compromise" location I have. I have checked everything I can think of to see if this location will interfere with anything. With the canopy closed obviously there is no issue, Withe the canopy fully open I will loose about 1/8" to the fully open position
The antenna is stiff enough that I don't think it will whip and hit the sides of the VS in flight but time will tell on that one.
Any thoughts from any of the 8 builders out there would be appreciated

User avatar
bullojm1
Chief Rivet Banger
Posts: 1317
Joined: Sat Mar 25, 2006 6:37 pm
Location: KDMW
Contact:

Re: ELT Antenna Placement

Postby bullojm1 » Sun Aug 14, 2016 10:50 am

Craig,

I went through a similar dilemma on my RV-7 on where to put the antenna. Most of my concern was it ripping off the fuselage during an accident. After analyzing all of the different locations, I decided putting it under the empennage fairing provided the most protection of the antenna during an accident, with minimal chance of the antenna ripping off of the structure. I also put my ELT on the aft portion of the fuselage - during a bad accident I have seen the two skins of the fuselage separate - the the ELT and the antenna were on different skins, then the ELT would become separated from the antenna.
Mike Bullock
http://www.rvplane.com
RV-7 | Superior IO-360 | Whirlwind 200RV
Garmin GTN650 | GRT Dual Sport SX EFIS
Status: FLYING!

User avatar
leffler
Class E
Posts: 170
Joined: Sat Sep 19, 2009 10:31 pm
Location: KDLZ
Contact:

Re: ELT Antenna Placement

Postby leffler » Mon Aug 15, 2016 10:12 am

The problem with this type of dialogue is that nobody knows what position the aircraft will be in after an incident. It may flip and be upside down or it may not be.

I ended up putting mine in front of the vertical stab per manufacturers recommendations. My thoughts were that I should know when there is any issue and be able to hit the button on the panel before landing. This would give the first responders a chance to get my gps positioning prior to landing. Then if the antenna is destroyed in the landing some position information would have already been broadcast.

The downside is if a situation where I or the passenger couldn't or don't have time to hit the button.

In my mind there a too many variables in either scenarios. There isn't any perfect answer, but at least with my way of thinking, I have a better chance of broadcasting my position while still in the air than afterwards on the ground.

If you are really paranoid, you could carry a spare antenna if you antenna is destroyed during the landing.
Bob Leffler
RV-10 - Flying
http://mykitlog.com/rleffler


Return to “RV 8/8A”

Who is online

Users browsing this forum: No registered users and 3 guests