ELT/strobe mount

[prkaye]

I bought both the left and right ELT/strobe mounts with my fuse kit (one for ELT, one for strobe supply). Looking at installing them now, before the upper skin is on my aft fuse and before it is mated to the center fuse.
I am confused about two things:

1) Based on the location the instructions have you put these, won't the ELT/strobe power supply end-up right where teh rudder cable is supposed to go? I'm basing this on the position of the rudder cable holes in the adjacent bulkhead.

2) How the heck can I drill up through the 4 holes in the bottom flange of the mounting bracket into the j-stringer?? The skins are totally in the way. Only solution i can see is to drill 3 or 4 new holes down through the stringer into new holes in the flange of the bracket.

[jlfernan]

The brackets come close to the cables but they won't touch. I did make a indentation with my dremel where the cable pass just to give them a little extra room. To drill the holes thru the lower stringer, after the top holes are drilled and clecoed, use side cleco clamps to position the bracket on the stiffner, then lay an inspection mirror on the bottom skin to allow you to see the holes. Use a side angle drill to make the holes. A problem you will also run into is you probably won't be able to insert the blind rivets and the puller below the stringer. One trick is to bend the stem of the blind rivet to allow the puller to grab the the stem and allow you to pull it.

[LettersFromFlyoverCountry]

This was my experience.

[Oldgeezer]

Originally Posted by prkaye

I bought both the left and right ELT/strobe mounts with my fuse kit (one for ELT, one for strobe supply). Looking at installing them now, before the upper skin is on my aft fuse and before it is mated to the center fuse.
I am confused about two things:

1) Based on the location the instructions have you put these, won't the ELT/strobe power supply end-up right where teh rudder cable is supposed to go? I'm basing this on the position of the rudder cable holes in the adjacent bulkhead.

2) How the heck can I drill up through the 4 holes in the bottom flange of the mounting bracket into the j-stringer?? The skins are totally in the way. Only solution i can see is to drill 3 or 4 new holes down through the stringer into new holes in the flange of the bracket.

Phil
when I mounted mine, I marked the location on the J stringers and the bracket and then attached the lower half to the J stringer, then held it out on an angle and used a 12" #30 drill to drill straight down thru the J stringer and the bracket. Then you can pop rivet the lower half the same way instead of trying to come up from the bottom. Then push the top in and drill down thru again. You will have to grind out a section of the top J stringers at each rivet location to get the head of the pop rivet gun in there.
Before you rivet the bracket in, you might want to mark the rudder cable locations and using a dremel drum sander, grind a recess on each side to give the cables more clearance. Also if you plan on grounding at that location, you can drill and mount a nutplate on the bracket for a later grounding point.
Hope this helps
Oldgeezer
RV9A wiring

[prkaye]

Thanks guys, great write-up Bob.
So the rudde cables go *behind* the mounting brackets, between the mounting brackets and the skin?

One thing i may do, isntead of pop riveting the brackets to the j-stringers, is to put a nutplates on the j-stringers themselves and screw the bracket in place. This way I can remove them easily if i later have a problem with rudder cable clearance or want to modify them for some other reason.

[LettersFromFlyoverCountry]

Originally Posted by prkaye

Thanks guys, great write-up Bob.
So the rudde cables go *behind* the mounting brackets, between the mounting brackets and the skin?

Yes, that's correct. The nutplate thing is up to you but really, we're only talking about a piece of aluminum with a flange here. About the only modification you could do here is bend the flange a little, if that were to end up being a problem. I'm not sure nutplates give you any flexibility you don't already have here.

[prkaye]

True, but what i was thinking is that if I needed to take it off for any reason during the build, it would be easier. Might also be easier to get a stubby screwdriver down under the bottom stringer than a pop riveter too. Of course getting a sequeezer in there to rivet the nutplates on to the stringer may be impossible... I'll have a good look at it later.

[LettersFromFlyoverCountry]

Originally Posted by prkaye

True, but what i was thinking is that if I needed to take it off for any reason during the build, it would be easier. Might also be easier to get a stubby screwdriver down under the bottom stringer than a pop riveter too. Of course getting a sequeezer in there to rivet the nutplates on to the stringer may be impossible... I'll have a good look at it later.

Right, but just keep in mind Van's constant building advice to us: keep it light. Theoretically, there might be a need to unassemble, any of the parts we assemble. But you have to calculate what are the possibilities of needing to unassemble a particular part.

I have no qualms with the science behind putting nutplates here. I guess I would assess the usual assessment, especially, when building the fuse: the benefit vs. the weight penalty. Two nutplates (or four or whatever) doesn't seem like much until you add them to all the other stuff on an RV that doesn't seem like much.

[prkaye]

yeah, that's very true. Especially after putting nutplates on EVERY hole in my floor for stainless steel screws, I'm starting to worry a bit about weight. Looks like I'll definately have to keep things like interior bells and whistles (fancy side panels etc) to a minimum.