[Captain Avgas]

I'm interested in recommendations for a PROVEN route for the wires that exit the most rear bulkhead on an RV7A and enter the lower rudder fairing (for the Whelen Nav/strobe light).

Does any body have any pix of their successful set-up.

I've checked the archives and I've seen a few pix of taildraggers with holes drilled through the spar of the vertical stabiliser. That of course will present a problem if the rudder needs to be removed.

At any rate I'm interested in the nose gear model solution.

 

[hevansrv7a]

VS Spar not a problem

..I've checked the archives and I've seen a few pix of taildraggers with holes drilled through the spar of the vertical stabiliser. That of course will present a problem if the rudder needs to be removed...

I don't see why that is a problem for rudder removal. Mine is through the VS just below the lowest hinge. The wires to the tail light(s) should have a disconnect plug in them. My rudder was removed for painting. No issues. Allow slack which will lay in the rudder bottom. Allow for rubbing issues, too, of course.

 

[Captain Avgas]

I don't see why that is a problem for rudder removal. Mine is through the VS just below the lowest hinge. The wires to the tail light(s) should have a disconnect plug in them. My rudder was removed for painting. No issues. Allow slack which will lay in the rudder bottom. Allow for rubbing issues, too, of course.

Ooops sorry, I meant to say running wires throught the VS spar would be a problem for removal of the vertical stabiliser.

I'm still a bit perplexed as to how you get your rudder off. I am imagining that you have a disconnect plug(s) for the tail lights inside the lower rudder tip. If so, how do you get the plugs out throught the rear of the tip. I am imagining that a hole for a grommet would not have sufficient diameter to pull the plugs through.

On the other hand you might have the disconnect plugs located between the rear bulkhead and the fairing. Is that a reasonable place for a plug.

Do you have any pix of your installation.

 

[hevansrv7a]

Ooops sorry, I meant to say running wires throught the VS spar would be a problem for removal of the vertical stabiliser.

I'm still a bit perplexed as to how you get your rudder off. I am imagining that you have a disconnect plug(s) for the tail lights inside the lower rudder tip. If so, how do you get the plugs out throught the rear of the tip. I am imagining that a hole for a grommet would not have sufficient diameter to pull the plugs through.

On the other hand you might have the disconnect plugs located between the rear bulkhead and the fairing. Is that a reasonable place for a plug.

Do you have any pix of your installation.

Sorry, can't find any pics of that. The tail lamp is the combo from Whelen and comes with plugs if I remember right. If not, just install on the wire ends. I cut a large enough hole (>1"?) in the aft surface of the rudder bottom to allow the lamp base housing to stick through it and that was large enough to extract the plug(s) through, too. I left enough wire inside the rudder bottom to come out through the end. I must have threaded the wires through the VS spar and lowest hinge bottom half before attaching the plugs. There is plenty of room at the forward end of the rudder bottom to draw the plug out completely for rudder removal. I just used some stiff wire to pull the real wires through. You are right that the plug would have to come off for VS removal, but I did all this after the VS was installed.

 

[Captain Avgas]

I must have threaded the wires through the VS spar and lowest hinge bottom half before attaching the plugs.

Thanks for the info.

If you drilled through the bottom half of the lowest rudder hinge then I am presuming that you also drilled through the rear fuse tie-down extrusion that is rivetted inside the last bulkhead. That's pretty tight in there....and maybe too thick for a bushing.

I'm also presuming that you did not drill a hole and use a grommet in the forward end of the rudder tip....rather you simply let the wires hang over the top edge of the tip. If so, are you concerned about the tip edge chaffing the wires.

 

[hevansrv7a]

Correct

Thanks for the info.

If you drilled through the bottom half of the lowest rudder hinge then I am presuming that you also drilled through the rear fuse tie-down extrusion that is rivetted inside the last bulkhead. That's pretty tight in there....and maybe too thick for a bushing.

I'm also presuming that you did not drill a hole and use a grommet in the forward end of the rudder tip....rather you simply let the wires hang over the top edge of the tip. If so, are you concerned about the tip edge chaffing the wires.

Correct on both deductions. I protected the wires where they go over the lip of the rudder bottom - some corrugated conduit. Easy to inspect, too.

 

[zkvii]

Possible options

Hi,

We have 7A with whelen stobe / light in the rudder tip. What we have done so far....

Drilled and snap bushed the rear bulk head

And after trying a simple snap bush on the rudder tip - I've evolved it to a 'funnel' duct.

The strobe and 2 nav light wires go through and I may well add some heat srink / sleaving just to help any chaffing. The plugs connections are in the rudder tip - will require removal of the pin from the connectors to remove the rudder - but not something I expect to do often..... Not flying yet - but looks good on the ground.....

HTH,

Carl

 

[lrfrey]

Excellent photo's Carl. I just finished mine a few days ago, I came thru the VS exactly as you did. I used a 1" hole and rubber gromet with a large opening. To guide the wires to the exact center, I used an adel clamp attached with the lower left bolt. It sits at a small angle, probably would vary depending on the relationship of the VS hole and Rudder hole.

Larry

 

[Captain Avgas]

Excellent photo's Carl. I just finished mine a few days ago, I came thru the VS exactly as you did.
Larry

Hi Larry, it seems from Carl's pix that he did not in fact come through the VS...he drilled through the aft bulkhead MISSING the the VS. Is that what you did also. This is one of those threads where a photo would be worth a 1000 words.

 

[zkvii]

To clarify - For us - the snap bushing is lower and outboard of the VS spar - the VS comes on and off without affecting it. The disadvantage of being that low is the cables have a real Z form. I'm don't know if there is a 'right' - just what Ive done so far....

Carl

 

[Captain Avgas]

Maybe for the sake of anyone who looks this up in the archives I'll post what I did for my final solution. Remember this is an RV7A and might not apply to other models..

1. Firstly I came through the rear bulkhead in the same location as Carl Morgan (the Kiwi)...extreme lower left corner (see photo). REASON: The Kiwis are pretty smart....and it means I can remove the vertical stabiliser without touching the wiring. It also means I can use a bushing through the bulkhead...I like that.

2. Secondly I routed the wiring up through an Adel clamp attached to the left bolt at the lower rudder hinge bracket. This positions the wiring to enter the forward end of the rudder tip. I also sleeved the wiring in this area. REASON: Wiring is properly clamped...no chaffing possible.

3. Thirdly I removed some of the upper lip of the rudder tip (forward end). I had to do this anyway because I found that the original tip was hitting the aft fuselage at full rudder deflection. REASON: Allows the wiring to enter the rudder tip over the top of the rudder tip without chaffing on the tip lip (no holes or grommets etc required in forward end of tip). Also enables me to remove the rudder by simply pulling the plugs out the back of the rudder tip.

4. Fourthly I used nutplates and ss screws and ss tinnerman washers to fix the rudder tip to the rudder. REASON: Good to be able to get in there to inspect the wiring...or to remove the tip for repairs if damaged.

5. Fifthly I installed an Adel clamp in the bottom of the rudder tip to direct the wiring as it enters the tip. It's an oversize clamp so it allows the wiring to slide but keeps it orientated in the right direction to eliminate chaffing as it enters the tip. REASON: No chaffing.

6. Finally I put a wiring loop inside the tip behind the Adel clamp. REASON: Allows me to pull out the light fitting from the rear to change bulbs without unscrewing the entire tip.

Here's a few pix to illustrate what I mean. You can left click on the pix to enlarge them and improve resolution.







Archive: tail light aft wire wiring route routing rudder navlight light strobe bulkhead tip fairing

 

[Rockyjs]

Is there suppose to be a drain hole(s) in this lower fairing? It seems like it would be easy for water and dirt to collect in there. I notice several builders cutting the leading edge even with the horn. Are interference issues common here?

 

[Captain Avgas]

Is there suppose to be a drain hole(s) in this lower fairing? It seems like it would be easy for water and dirt to collect in there. I notice several builders cutting the leading edge even with the horn. Are interference issues common here?

Yes, there is supposed to be a 1/4" drain hole at the "low point" of the fairing. It's called out on DWG 7. In reality water will gain entry to this fairing whether it is cut back or not. There is an aperture in the rudder at every rod end bearing where water can enter and run down the front face of the rudder spar...with it all finally being collected in the lower fairing.

And yes again....other builders have also reported interference of the fairing with the aft fuselage at full deflection. Maybe the latter could be remedied by adjusting all the rudder rod end bearings. But I wanted to run my wiring through the fairing aperture without chaffing so I removed the lip.

 

[Rockyjs]

Thanks Bob for pointing out the drain hole note on DWG 7. It's amazing how you can look and look and not see some things.