Aft Battery cable interference problems

Task - run a battery cable from the back of the plane to the front. I thought I could do this but I'm running into interference problems around the wing spar box.

I have drilled the holes in the location identified in OP11. This causes areas of possible interference.

The first problem is possible interference with the aileron pushrod. See the attached pictures. I've put a piece of straight fuel tube to represent where the aileron pushrod would be if it was actually rubbing on the holes in which it runs. Of course that won't happen but I want to keep as much clearance from that position as possible.







On the aft side, even keeping the cable as low as possible, it looks like it will come very close to the aileron pushrod when I install it. Highly undesirable I expect. I could put some silicon down and glue the battery cable to the floor to hold it down but I don't know whether that would be strong enough. Perhaps I could get a P-clamp and attach it to F814A-L close to the aileron pushrod hole to hold the cable close to the floor there. But it will be difficult to get the cable back up to the hole in the spar web then.

I have looked again at drawings 25 and 31 and they show the cable travelling further inboard and higher than the holes shown on OP11 suggest. If I run the cable along the top of F814A-L and then bring it back down to the OP11 hole location it will run directly through the space where the aileron pushrod will run.

Has anyone else found this problem and if so, how have you solved it?

The next problem is interference with the rudder cable on the forward side of the spar box. Bringing the battery cable up to where the P-Clamp is shown attached to the F-878PP -L mid cabin brace on drawing 31 means the rudder cable will rub on the battery cable. Once again undesirable. See the attached picture. The rudder cable is not actually hooked up to the idler bar for the rear rudder pedals. it is haning down in this picture but even when hooked up it will rub on the battery cable.



I could just put some tube over the rudder cable and possibly tie that to the battery cable to prevent friction between the two. Or once I have installed the fuel lines around the fuel selector valve I could move the battery cable more outboard, attaching the P-clamp with a piece of angle at an appropriate place, perhaps on the F883A Fuel valve bracket.

Has anyone encountered this before and how did you fix it?

Thanks for your help.

BTW, will there ever be a simple job that can be completed without having to solve other problems? I've been doing this for three years so far and the moment I think, "I'll just do [insert the simple looking task]," I am bound to be in for a depressing bout of creating problem then solution then problem caused by the solution, seemingly forever! I'll get there in the end I suppose but man I find it frustrating. I try to think carefully about things before I drill any holes but I still find I don't think of everything even when I think I must have!

I just want to fly but I don't want to carelessly rush either. I reckon I've got another 3 years or so before I can do that. What a character developing project this is!

Ken Stanton
RV8QB

Use Google!

I just did a google search on rv8 battery cable and I came up with some pictures. Here is the link:

http://www.rv8.ch/index.php?topic=wiring&page=2

Some of the pictures are from an article on the comm antenna mount, but you can see the orange battery cable.

There are a lot of areas in the kit that require you to think in 3d to try to figure out how things will be affected. I've had to re-do many parts due to interference that I didn't see until the part was on. The most recent one is the battery mount in the tail. It was too far forward, and interfered with the baggage area.

I'm sure I will be much faster building my 2nd RV8!

Thanks for the thoughts Mickey. Your website is a wonderful help to those of us following behind.

Part of the problem is that there appears to be an inconsistency between drawings 25 and 31 and OP11. I'll wait to see if someone else has some pictures or solutions too.

Thanks

Ken Stanton
RV8QB

Hi Ken:

Regarding clearance between the battery cable and aileron push rod... what I did was to anchor the battery cable with an adel clamp in the in the lowest most forward position possible, just aft of the spar.

If I place a long dowel through all the lightning holes I get about 1/4 inch clearance between the cable and the dowel.

Considering that the cable will not budge and that the aileron push rod will not be resting on the bottom of the lightning holes, this should work.


I too have pondered the clearance between the battery cable and rudder cable on the forward side of the spar box. I initially had my battery cable clamped to F-878. However, I removed the clamp after noting the interference and now just have straight run to the gear box. It is still on my punch list to check during final assembly.

-Mike Draper
RV-8 finish

Above the aileron pushrod

I believe the main difference between the way you did it and the way I did it is I ran the cable above the aileron pushrod. Check this pic:

Thanks Mike.

Do you have a photo of the Adele clamp location? I think I have the idea however and I will try that for the aft problem.

I also thought I would remove the clamp and just run the cable straight to the gear leg tower. Do you have the fuel lines in there yet and if so how are clearance issues with them and how do you make sure the battery cable and the fuel lines stay separated? Any pictures available?

Thanks for your pictures Mickey. On reflection I think I would have preferred to run the battery cable as you did but I figured there was a good reason drawing OP11 put the holes where it did so I ran with that. Wish i'ld looked more closely at your pcitures first!

Ken Stanton
RV8QB