VP-x access

I'm in the process of choosing a location to mount my VP-X box. I see most folks just mount them on rails between the firewall and sub pannel. I can't help but think that access will be terrible once that forward skin is riveted on. Has anyone come up with a better location? I've been trying to make a hinged setup work so it can swing down from behind the sub pannel, but so far I can't quite find the room for it.

That's were I mounted mine on my RV-10. However, lesson learned the hard way. I had my upper fuselage assembly upside down on my dining room table to build the wiring harness. I then drill the mounting hols and installed some nutplates on the bottom of the ribs.

Six months later after riveting the upper fuselage assembly to the fuselage and firewall, I attempt to install the VP/X. Should be a five minute job to install four bolts. Wrong! It turns out that I overlooked the alighnment of the ribs when I made the mounting tray for the VP/X. When the ribs were riveted to the firewall, they moved from where they were when I made the VP/X mounting brackets. Two of the four holes were off by about 1/4". Not a really big deal, but certainly a PITA having to work under the panel to fix that problem.

If I was doing it again, I would probably put it in the same place, but omit the nutplates.

cropdusterdave said:

I'm in the process of choosing a location to mount my VP-X box. I see most folks just mount them on rails between the firewall and sub pannel. I can't help but think that access will be terrible once that forward skin is riveted on. Has anyone come up with a better location? I've been trying to make a hinged setup work so it can swing down from behind the sub pannel, but so far I can't quite find the room for it.

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I don't have the VP-X but do have the VP-50 that has the main CPU (red box) mounted between the firewall and sub panel as you noted. I cut two access plates 8x11 inches directly in front of the windshield on either side of the center rib. Perhaps this is something you had not thought about and could work for you. I have had several occasions to open the plates and gain access to everything behind the sub panel. I am glad I put the access plates in although I spent a lot of time going back and forth on whether to do so during the build. I have no regrets of doing so.

Just food for thought.

I mounted mine in the recommended place - on two rails attached to ribs between the firewall and subpanel. I don't have the top skin on yet but access from below is fine as tested lying on my back under the panel. Will probably be much easier to remove the VP-X box than to run new wires for the next electro gadget.

I've handled them in various ways, the latest project I mounted both the Lightspeed Ign module and VP-X in layered brackets to the ribs, access thru panels cut in front of the w/shield.

I'm thinking for future projects with multiple modules, I'd create a larger shelf between the firewall & subpanel that would be hinged in the front & secured with 2 or 3 fasteners in the back. The whole panel would swing down for access. Considerations- be mindfull of obsticles like throttle cables, brake lines, etc., provide good grounding to this panel as some modules may require it, leave room for future toys.

A couple thoughts for Larry's installation- consider moving the Dynon back-up battery forward & mounting the transponder where the battery is currently mounted (I'm assuming this is a Dynon installation & the xpdr will fit in that position) as xpdrs are maintenance items & battery will probably never have to be touched again.

Hanging down

I don't have a good picture but will take one later. I mounted mine upside down between the center rib and the left rib. Fully accessible with nutplates mounted on the flanges of the ribs. I made my own brackets to make it work.

I highly modified the sub panel. I cut virtually everything away and fabricated doublers for strength. By pulling the EFIS screen on either side the components will all be accessible.

Also, be sure not to mount anything too close to the top. Otherwise you won't be able to buck the rivets for the top forward skin.

Lots of planning!!!!

Ralph Inkster said:

A couple thoughts for Larry's installation- consider moving the Dynon back-up battery forward & mounting the transponder where the battery is currently mounted.

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Thanks for the idea, Ralph. I will probably do exactly that. Make the antenna run easier, too. Everything is temp attached while I sort out changes like this.

I mounted the VP-X box on some aluminum angles that are held on with screws and nutplate on the forward panel ribs. Four screws removed from the bottom will drop this down for future maintenance.

Bruce's pictures show one of the standard methods, and the other descriptions above will work as well. Remember to leave plenty of room for the connectors on both sides, especially if you have the VP-X Pro instead of the VP-Sport (Bruce's picture shows the Sport). The black Molex connectors are fairly tight (in addition to locking in with a tab)--much more tight than the DB connectors shown, and you will appreciate any additional room you give yourself whenever you need to disconnect those J-8, J-10, and J-12 connectors.

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Stephen