Center Section Issues

longline · #1 12-03-2016, 03:17 PM

have been discovered on an RV8. (Moderators, move where you think this fits...)

My kit was purchased from the original buyer/builder. He seems to have done an adequate job on the fuselage... but I discovered that there are holes in the wing spar center section forward upper and lower carry through left open in case the kit is built as an RV8A. These holes should be filled with bolts in the case of an RV8.

These bolts were not installed in this case, and would be (nearly) impossible to install if the wings were on the aircraft. I am sure that, structurally, this is somewhat critical.

It might be wise to make sure that these fasteners are installed in any aircraft that uses common center section components for RVX/RVXA.

woody

RV8Squaz · #2 12-03-2016, 03:31 PM

https://www.vansaircraft.com/pdf/sb12-08-14.pdf

longline · #3 12-03-2016, 03:48 PM

that is not what the issue is, at all. The bolts you reference are for the wing attach. The open holes I am talking about are inboard from the spar attach area.

There are 6 open holes on the upper forward carry through. I think there are 4 on the lower forward carry through. These open holes are used to attach the -A aircraft landing gear weldments to the center section. In the case of the tail dragger, these open holes are to be filled with bolts.

I did not query Van's about other model aircraft, but the RV8/8A center section is, apparently, delivered from the factory completed, in the kit. It is up to the builder to ensure that these holes are filled with bolts if you are not building an 8A. It would be easy to miss this step during assembly, as witness my kit.

Sorry if my original explanation was not clear. This is an entirely different set of bolts.

woody

skyking902001 · #4 12-03-2016, 07:40 PM

Here is an entry from my kit-log on 2-2-12 which I believe addresses the issue:

"On the RV-8 quick build there are 12 bolts that are left out during assembly that need to be installed. The manual has you begin QB assembly on page 8-42. This skips the 2 or 3 lines on page 8-10 which refers to installing these bolts. The plans call for 12 AN4-11A bolts, AN960-416L washers and AN365-428 nuts. These bolts go thru the F804A2 center section bulkhead and the F804F1 center section bar. The bolt heads are on the forward side of the bulkhead and must be torqued from that side (no room in the spar cavity for a torque wrench). I did not want to turn the bolt heads against the anodized bulkhead, so I used an AN960-416L washer on the bolt head side. Now with a washer on each end, there is not enough threads showing after adding the nut. I substituted the bolts for AN4-12A, with a thin washer under the bolt head and a regular washer on the nut side. When tightened, it left 2 to 3 threads showing. Now that I got the hardware figured out the real fun began. If you are reading this log, install these bolts early?before the control column and rudder cables are installed. I taped a washer wrench to one end of a yard stick and a wrench to the other end. It was easy to get the washer on, but the nuts were not so much fun. Nancy turned the bolt heads while I ?fished? with the AN365 nuts taped into the wrench. Long story short, after a couple of hours, I had 9 of the bolts installed and torqued. Hope to get the rest tomorrow night."

longline · #5 12-03-2016, 10:58 PM

all I was trying to do was alert people of a gotcha that would be easy to overlook, especially if you did not do the early part of the build. Easy to overlook, easy to inspect to make sure it was done.
As has been pointed out, it is not so easy to fix later in the build.

A tip for those that need to do this: use a 1 inch wide piece of 1/4 plywood, about 2 feet long. Drill a hole in it such that a vise securely sets the nut in the hole. Superglue the washer to the nut with a little dab of glue. Use this extension thru the left and right spar access area to allow a helper to thread the nut/washer onto the bolt as you hold the fixture in place.

It is awkward to access the nuts to allow torque to be set on the bolts, but can be done. Once I figured this out it took all of 30 minutes for all of them to be finished.

woody