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Archive for the ‘ELT’ Category

Installed ELT Antenna – 2 hrs

August 18, 2013 Leave a comment

Sunday Aug 18, 2013

I spent most of my time this weekend working on the computer planning out the electrical wiring schematics and building a parts list for an order to Steinair. This electrical network is more complicated than I expected.

The one visible accomplishment was the installation of the ELT antenna. I go the idea of mounting it behind the roll bar from Chad and Bekah’s web site. I don’t want to mount it outside the fuselage and this seems better than under the empennage fairing.

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Categories: Avionics, ELT

This Bird Has Legs – 8 hrs

December 1, 2012 Leave a comment

Saturday Dec 1, 2012

Today was one of those rare days where a bunch of significant things were completed. I started this morning working on the ELT mount. The parts needed to be primed so I scrubbed all the parts with Simple Green, rinsed and dried them. The weather was not great this morning and the humidity was kind of high but I was able to get a decent coat of primer shot onto the parts in the paint booth. After drying a while I riveted them together with the nutplates for the ELT tray. Here is the bracket by itself.

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And here is how it looks with the ELT tray installed. The ELT traps are clamped down under the tray by the mounting screws.

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I installed the bracket with the tray attached into the fuselage using CS4-4 pop rivets and installed the ELT to the tray. I’m guessing it is stiffer than the Vans bracket because it ties directly into those stringers without the large flat surface of the Vans bracket. This mount sure seems stiff. It also does not interfere with the rudder cable and it keeps the center of gravity as far forward as possible.

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Next I installed the Dynon remote transponder unit. It also has a tray which I mounted with three screws to the center rib behind the pitch autopilot servo. I drilled the holes in the rib and used locknuts to install it. This did not take long once I got my less-than-flexible body back there where I could reach this area. The transponder just snapped into the tray with a wire retaining clamp on the aft end. Next step with the ELT and transponder will be making coax cables and running wiring.

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Several months ago I purchased an engine crane at Harbor Freight in preparation for hanging the engine. Today was the day that I opened the crate and assembled this thing. It took about 45 minutes to put all the pieces together and get it operating. I have to say I am impressed with the quality of this thing. It lists for $200 but I bought it with a HF coupon for $100 and at that price it is a steal. It is perfect for this job and it looks pretty good too. I just wish I had more space to store it.

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I didn’t really plan this in advance but since I had the crane operating I lashed it to the engine mount and lifted the front end of the fuselage. That gave me enough clearance to insert the nose gear which has just been sitting in the corner anyway. I had to jiggle it quite a bit to get the bolt hole aligned but I got it in. At that point I had to decide to go ahead and put the two main gear legs on or remove the nose gear for another day. I thought, “It’s time to give this bird some legs.” With the crane attached I just lifted the front a little further and I could slide the main gear legs into the sockets and bolt them in. Wow, it is cool that this is done – it’s a major milestone.

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One lesson learned РI buggered up the threads on one of the gear leg bolts trying to get it in before the holes were perfectly lined up. After that I got smarter and went to the hardware store a picked up a 3-inch long, 5/16 diameter bolt that I ground down to make a tapered drift pin (see below). Once I got the holes close I tapped this pin in to center everything up before installing the real bolt. I will have to order a replacement for the one bolt I buggered.

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Installing ELT – 5 hrs

November 29, 2012 Leave a comment

Thursday Nov 29, 2012

This week I have been working out how I will install the ACK E-04 406 MHz ELT. For weight and balance reasons I want to mount it as far forward as possible. It’s only 1.8 lbs but every ounce behind the baggage compartment is important. Vans makes an ELT/ strobe power supply bracket that mounts to the side stringers in the bay behind the baggage compartment but I have read that the rudder cable rubs against it, so I am not inclined to go that way. I decided to try to make a custom bracket from Alclad scrap that mounts lower than the Vans bracket away from the rudder cable.

I started by sketching out a concept and then I cut out cardboard pieces as a model. It will have a shelf just large enough to mount the ELT tray and two ribs will attach it to the stringers of the fuselage. I transferred that pattern to some .020 alclad sheet which is easy to cut with snips and to bend to shape. After fitting it and making some tweaks to that, I was satisfied with the fit and I transferred the pattern to .032 alclad sheet which is thick enough to be quite stiff. Here is a photo of that design after I match drilled it to the two fuselage stringers.

Then I took the parts out out, drilled all the holes for rivets and nutplates, dimpled holes and deglossed it. If you look closely at the photo below you can see two diagonal gussets that support the ELT shelf where it overhangs the vertical rib. Those gussets are directly under the mounting points of the ELT tray so the loads are carried directly into the stringer.

My next step with this is to prime the parts and rivet them together first, then pop rivet the assembly into the fuselage. There will be nutplates for the four screws that mount the ELT tray so it will be easy to install and remove. This will all make more sense when I can post photos with the ELT installated.

Categories: ELT