Non RV-8 ACK 406 ELT Install

[twcroy]

Just a quick check to see if folks are/have installed the ACK 406 aft of the baggage compartment (I have a servo back there, but don't think it will interfere, and will look to mount it in the center somehow) with the antenna on top of the fuse about 1/2 way between canopy and VS? My old ELT failed and I bought the 406. I have a 396 and will probably try to connect it, hoping it's close to the instructions Bob Walden provided back in 2012 for the 496. I don't want to mess with the 430 right now.

Thanks for any thoughts,
Tim

[twcroy]

Hello all,

I wanted to provide what I've learned on this in case it can help others. I called Vans on the 406 ELT install and they recommended installing it on a plate of the horizontal stabilizer with the antenna bent 90 deg and pointing aft in/into the VS (vert stabilizer). I have a GRT magnetometer there also. GRT didn't think it would be an issue, and if so to recalibrate it. They thought periodic testing with the ELT transmitting shouldn't damage the magnetometer. If anyone has tried this, please advise.

Lastly, I had my pitot-static and transponder tests today. I'm certified VFR only at present. I tightened all the connections I could find, but still no luck. The A&P suggested using teflon tape to help stop the small leak. Any thoughts are appreciated. I'll also search the posts more.

Tim

[Bevan]

In my RV7A, I mounted the ACK 406 aft of the baggage bulkhead where I have made an equipment bay by closing up the next bulkhead and fabricating a floor. The shoulder harness cables go through this new compartment. The original upper baggage bulkhead is now hinged for access. This location has worked out well as it doesnt put the weight too far aft and allows the antenna to be placed close by in the rear of the cockpit under the plexi canopy as others have done.

An easier way would be to simply make a mount near the floor or fuse side immediately aft of the baggage area.

I wouldnt think the antenna should be enclosed by aluminum structure such as the VS.

Bevan

[Carl Froehlich]

Easy install is the ELT on the shelf in the baggage compartment, and ELT antenna mounted horizontally under the empennage fairing, the base mounted on the last full bulkhead in front of the VS. No reason not to mount the ELT on a bracket behind the baggage compartment other than access to the switch.

All you need for GPS position is a serial output from your 430 - or anything else that is compatible. Remember to register the ELT with NOAA. https://beaconregistration.noaa.gov/RGDB/index
Don't forget you need to provide power to this ELT to keep the battery alive. I just replaced my battery (five year expiration date) and the old one tested just fine on the bench.

You need a test rig to check for static leaks. Just tightening joints never fixes the problem. If you check everything and still don't find the leak, and if you have an old school airspeed instrument don't overlook the glass being the source of the static leak (the static line is connected to the inside of the can, the pitot goes to the internal bellows). Bypass the airspeed instrument and do another leak check to confirm/deny. If the glass is leaking, you can carefully put a very small amount of black RTV on the outside joint between the glass and the can to seal.

Carl

[twcroy]

Thanks Carl and Bevan. Yesterday I riveted the ELT bracket to the passenger-side of the baggage compartment's wall below the shelf where the old 121.5 was. It's a little off center (don't know if it's over 10deg), but I may remount it on the shelf it it's straighter. I'm still checking into the antenna mounting, Vans thought the fiberglass fairing would provide exposure for the signal, but I don't know if it's the best place for it.

The altimeter has two lines going to it and the airspeed indicator via a t-connector for each . I think this means it's not the old style since one line is likely the static line, but I'll check with my A&P to ensure. I guess my next step is teflon tape and ensure there are only three lines going to the air data computer that I could feel and tighten yesterday.

Thanks again for your help,
Tim