Show me your rudder cable/spar location

Is this where your rudder cable passes through your spar?
Here is why I ask.
Since I am running rear seat rudder pedals, after the cable exits the spar you can see it heads uphill to connect to the rear pedal idler. The F-805 cable support aft of the spar is equally high up. Place the low spar pass through between the two high mounting points and you have yourself a great stainless steel saw to attack the spar. I assumed that was the reason for the length of poly tube except mine is not long enough to protect both the spar and the F-805 support. I was looking at various way to achieve both when I noticed drawings depicting the rudder cable passing through the spar much higher up.
So, where does your rudder cable penetrate your spar? This is a QB fuselage.

Rudder Cable

Sam, my fuselage is not a QB, and I do not have rear seat pedals. My rudder cable penetrates the spar web about the same height as your idler attach point. Seems to be on a direct line from guide immediately to the rear of the spar.
Do you have a unused pre drilled hole at the top of the spar web?

Nope. The two larger holes you see down towards my fuel line are the only two holes of that size (on this side, same two holes on the other side). I looked again this evening and can confirm there are no pre-drilled holes up higher that are not visible in this picture. Even the two small #40-ish size holes you can see on the front of this spar do not appear on the aft face of the spar. It is a mystery. I will shoot Van's a question and see what they have to say.

It seems I missed a note on DWG 64 about enlarging holes for the rudder cables during the audit of the QB fuselage. The next time I get back to the hangar I need to revisit those small pilot holes. I was pretty sure they did not line up front and back side but maybe they do.

Now I need to go back through my build manual when I audited my QB and figure out where I missed that.

I see the instruction now, right there in step 1 of the center section build up on page 8-9. I can only assume I saw the written instruction, noted the approximate position on the drawing, looked at my QB spar and saw a hole of the correct size in about the right place and moved on to the next step. I can even recall measuring to confirm the correct hole size.

Big thanks to Greg Blanck for pointing me in the right direction.

It is things like this that make this place is well worth the donation to DR. I am paid up for 15 but it is almost time to pony up for 16.

Be sure to note that the cable passthrough is different for tricycle and taildragger planes. And quintuple-check that you have the right hole before enlarging. I got in a hurry and enlarged the wrong hole while prepping my center section, and I'm quite sure that was the loudest I've cursed for the duration of this build. I was very concerned that I'd ruined the center section, but I got an approved repair plan from the mothership and moved on.

Made it out to the hangar this afternoon.
Yep Phillip, knowing there wa a 50/50 chance of making a mistake I bet I looked, counted rivets, re-checked and the re-checked again 27 times before I went to work with the unibit. I even put a piece of red tape over the 8A hole.


Taking a look at everything I can see how I thought that one hole (the correct hole for a TW) did not go all the way through. The hole on the aft side of the spar is very well hidden by the floor support. I couldn't see it unless I used a mirror. Thanks again for everybody's input.

Sam, If you have concerns of cutting through the bushing, you can take a smaller bushing cut it with a Razer blade, slip it over the cable and snap it in place. It can be replaced (removed) with a piece of alum tubing slotted to fit over the cable and tapered on the end to disengage the locking tabs.

You will never wear out the original bushing.

wrong holes, damm it!!!!

Hi Guys,
I commited the same mistake, and I'm still cursing about...
I used the unibit to enlarge the spar holes up to 1/2". Then I discovered I enlarged the wrong ones on the rear side of the spar...&$%/(%"%... not sleeping well since.
Asked Vans for the proper solution and they suggest me to rivet a doubler covering the hole..
I don't like much the idea of adding even more holes to the spar!
Wandering if I may place a 1/2" Bolton thight in the wrong holes... wouldn't it be a better solution?
Regards! Alex

Not sure what you mean by "1/2" Bolton thight," but my main concern when I misdrilled my hole was less that I had an extra hole, and more that I was going to have two large holes in very close proximity without much material between them. Here's what the web looked like after I'd enlarged the second hole and laid out my doubler:



Calipers put the material width between the holes at about 5/32". My abortive engineering education was quite a whole ago, but my gut says that that little piece of material could easily be a stress concentration. And on a similar I'm-not-an-engineer note, I don't think that adding more holes to the spar is a problem (within reason, of course), provided they're spaced appropriately and filled with rivets.

Here's my finished doubler after riveting, from the inside of the spar web:



And from the outside:



Note that the doubler shares four rivets with the floor angle, and that I've then added two rows of five rivets at the top and bottom edges. This was the exact repair plan I suggested to Van's when I emailed about my foul-up, and they approved of my proposal, so I went with it.