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unsure of cockpit rails

J

jscottpilot

Active Member
I have a new fuselage kit. All has gone together pretty easy to this point. I am on page 8-28 of the instructions where it says "Align the outboard edge of the 816 Cockpit rails so they are flush with the outer surface of the F-823-1 Mid Side Skins and clamp in position. Note: Pay particular attention to the fwd end of the cockpit rail."

I have done exactly what they have said to do. I can align the edge of the cockpit rails with the outer skin all the way up to the wing center section and I can align the forward part of the rail. Where I run into a problem is where the two skins meet up. I am about .070 inside of the outer skin. Frankly I dont see how you can align with the outer edge of the skin because the cockpit rail is straight and does not take into account the thickness of the outer skin.

If someone has experience with this I would appreciate some help.
 
I just got through with the same experience. Vans said that it was because the flange that the skin attaches to at this location was no bent to 90 degrees Sorry I do not have the part numbers. I pulled both forward and mid skins off and made sure they were 90dgrees. It helped a little bit but it still did not line up perfectly with the edge of the skin. They also said if the upper longeron was not bent correctly it might cause a problem. Correctly being slightly tilted inward at this location. Mine are still not perfect but it's drilled so I will press on.
This was the first thing I have ran across on the match hole kit that did not fit like a glove I guess no one is perfect but they are getting close.
Chad
 
I drilled the cockpit rails as close as I could according to the instructions. They are still not perfect. I have a friend that bought a quickbuild fuselage. I drove forty miles to look at the "factory work", mine are closer to perfect than his. The instructions say the edges of the cockpit rails should be perfectly aligned with the outside edge of the mid side skin. What it should say is align it as closely as possible using clamps. Clamp it tighlty without distorting things and accept whatever differences there are. I think this is the final word in this.
 
jscottpilot said:
What it should say is align it as closely as possible using clamps. Clamp it tighlty without distorting things and accept whatever differences there are. I think this is the final word in this.
Click to expand...


Amen, brother.
 
Cockpit Rail Fun

Hi folks,

I ran into this very same problem. I fiddled with it and got an opinion from Van's. Sounds like we have about the same tolerance. I had a much more interesting problem with the step of drilling the holes up through the seat back support into the rails. It also goes through a spacer. My first holes seemed really close to the edge so I moved the next ones over and really screwed it up. New parts on order. My advice here is, look really carefully at the alignment of the spacer, seat back support and rails before you drill.

Regards,

Michael Wynn
RV 8 Pre-punch Fuselage
San Ramon, CA
 
I am at this step and am glad that others are somewhat confused. My biggest concern is that when I cleco the cockpit rail into the top of the 804 bulkheads, the rail is not even close to edge of the skins. Am I missing something?
 
find someone who has a quick build kit and look at it. do go forward until you know you have it right. pictures would probably help.
 
Two types of -8QB

Interesting thread. I am not even close to this step but I did learn after getting my first QB kit that there are two types, one is built up from non matched hole parts, not sure if this is the same as what you call pre-punched and the other is made from matched hole parts. They sent me one that was not matched hole. After I learned of this I took the first one back and picked up one from matched hole parts. Van's tried to convince me to keep the old style on, said it would save me time. The turtle deck skin was already installed, but I wanted the matched hole technology, sure hope I made the right decision. What type of kit are you guys working from, was the turtle deck on or off when the QB arrived. Mine is a 8A QB. I just picked up my kit this past summer.

Cheers
 
I'm at the point of fitting the F-816 cockpit rails. I have run into the same issue at the center section bulkheads also. The outboard edge of the right side rail is about an 1/8" shy of skins and the left side is about 5/32". I've rechecked the bulkhead flanges to make sure they are 90* to the skins and I believe the longerons are correct also. I read the previous post about clamping around the fuselage and trying to pull the bulkheads inboard before drilling into the upper longeron.

Before I do this, can someone tell me what the width of the center section should be at this point? Measuring across to the outside edges of the upper longerons at the reference mark made for the notch in the cockpit rails, I have 31.75". At the same point to the outside edges of the skins, I have 31.875". Is the width a critical factor?

I'm also considering removing the clecos holding the rails to the top flanges of the center section bulkheads, sliding them outboard until they are flush with the skins, installing doublers under the flanges, then redrilling back down into the flanges. Any thoughts, ideas...?
 
I am at this point. I am less than 1/16" from being flush wih the side skin. I think it will be fine to proceed. Anybody got any advice?
 
Cockpit Rail woes

Hankies for everyone!!!... Including me. I wondered if I was the only one. I do have a unique twist though. I bought a partially built fuselage and after installing the roll bar, and later the rails I find that now the front cowl doesn't fit. The plans show dimensions from the firewall to the back of the roll bar and from the rear of the cockpit the the back of the roll bar. I used the distance from the the back of the cockpit. Turns out the there's an extra 5/8 of an inch somewhere between the firewall and the back of the cockpit. Anyone seen this before? I'm moving the rollbar to match the dims from the front but now my rails are short. Plus the the forward hole on the two hole inside tab isn't touching anything.

Lance
 
original question

During installation of upper longeron, directions stated to lay it in and pull, with a strap around the fuselage, at the gear boxes, to get the gear box flanges flush with the upper longeron. By doing this, it aligns the longerons properly. After that when it comes time to install cockpit rails they are very close, and only requiring a little adjustment and clamping for drilling. Mine came out flush. Howeve,r keep in mind that where the front and mid side skins meet, they are overlapped. This is above the spar center-section. The overlap only will be the thickness of the forward skin out. Hope this helps.

bird
 
Good information here. I’m at this step and about 0.05” inboards on the mid skin. The fwd skin at the overlap is obviously a bit more outboard. I’m going to accept this and move forward. Pictures attached in case others run into the same issue.

9D224A4E-E3FA-48FB-9CBF-F72E25C3E9AD.jpeg



84773E47-EDD7-4FFB-9095-16F80C4252C2.jpeg


And if I uncleco to align the rail with the outer surface, then the pre-drilled holes don't line up:

C8C0056F-FDB6-46B6-BA03-C1E80EE33D29.jpeg


On we go.

- Paolo
 
Presmini said:
Good information here. I’m at this step and about 0.05” inboards on the mid skin. The fwd skin at the overlap is obviously a bit more outboard. I’m going to accept this and move forward. Pictures attached in case others run into the same issue.

And if I uncleco to align the rail with the outer surface, then the pre-drilled holes don't line up:
Click to expand...

I think you will be ok to proceed and I think it's hard to get it perfect in this area given the longeron bend around the center section bulkheads.

But I do think you may get it closer if you can get the outboard edge of the upper longerons to be flush with the outboard edge of the upper flange on the gear tower face (which rivets onto the longeron).

You have a gap between the edge of the flange and the edge of the longeron, which I think is common, but you may be able to get the longeron flush.

For me the thick plate on the outboard side of the gear towers pushed the skins and longeron outboard. Maybe if you bend that piece more inboard at the top or match drill the longeron to the gear tower flange before drilling the cockpit rails then you can get it flush. Just my two cents.
 
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