VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 09-09-2018, 09:21 AM
Draker's Avatar
Draker Draker is offline
 
Join Date: Jun 2016
Location: Livermore, CA
Posts: 118
Default F-711 bulkhead prep

VAF searches show several builders encountering skin fit issues with this F-711 bulkhead. During prep I see mine are quite warped along the vertical axis:



Could this be related to later skin fit issues? Is there a way to straighten these so they lay flat? I know fluting tends to straighten about the horizontal axis (perpendicular to the flute) so I doubt that would help. I noticed other bulkhead ribs don't lay flat either.

Also, look at the flanges on F-711B as they come from Van's. Are these supposed to be squared like that? The instructions don't suggest it. I have an irresistible urge to round off those corners.
__________________
Ryan Drake
Livermore, CA
https://stiletto.smugmug.com/RV7
Donated 12/29/2017
RV-7A: Empennage and wing kits complete minus fiberglass, fuselage in progress!
Reply With Quote
  #2  
Old 09-09-2018, 11:54 AM
nilberg nilberg is offline
 
Join Date: Dec 2012
Location: Katy, TX
Posts: 163
Default

I donít think any adjustments are possible, they get riveted together back to back with some beefy flat aluminum bars (the ones used to bolt on the VS).

http://www.mykitlog.com/users/displa...252573&row=354

I donít think outside corners are as critical as inside corners (if at all ?). I took if the sharp edges because I didnít want them to scratch the skin when I fitted the skin.

Also remember, as both F-711 and F-712 are both two parts back to back, the flanges are bent in opposite directions, confirming to the cone shape of the tail.
__________________
__________________
Bjorn N - RV 7 in progress
Katy, TX
http://www.mykitlog.com/N741BN
Reply With Quote
  #3  
Old 09-09-2018, 12:04 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 2,950
Default Bulkheads

The single thickness bulkheads are not an issue. Don't mess with them much except to adjust the flanges so the fit against the skin properly. If you don't, lots of shims and frustrating riveting is ahead. Don't mess with any top skin flanges. You can adjust them when the time comes.
The double bulkheads require lots of flange adjusting. Forward side is different from aft side. Adjust all of them so they fit and the longeron is correctly positioned. Don't drill the skin to flange holes till everything fits. If you don't want the external rudder stops, look at Flyboy for a hidden Delrin stop.
Not an expert opinion. Just my $.02.
__________________
Larry Larson
Estes Park, CO
http://wirejockrv7a.blogspot.com
wirejock at yahoo dot com
Donated 12/01/2017. Plus a little extra.
RV-7A #73391, N511RV reserved (1,800+ hours)
HS SB, empennage, tanks, wings, fuse, working finishing kit
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
  #4  
Old 09-09-2018, 06:16 PM
PilotjohnS PilotjohnS is offline
 
Join Date: Jan 2016
Location: Los Angeles
Posts: 526
Default What i did

I tweaked them ever so slightly to make them flat. Also the flange needs to be at the proper angle with a tight bend. If the flanges tend to fan apart before the sharp flange bend, this could cause fit issues. I would suggest clecoing the double bulkheads together and then checking fit to side skin and bottom piece. Much easier to do this now before riveting the two bulkheads together. Also make sure front bulkhead is dead center on rear bulkhead before match drilling the rivets that hold the double bulkheads together. The more perfect the fit now, the easier assembly later.
__________________
John S

WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.

Extra dues paid 2018, worth every penny

RV9A- Status: tail feathers done less tips
Wings done less tips and avionics
Fuselage 30%
www.pilotjohnsrv9.blogspot.com
Reply With Quote
  #5  
Old 09-09-2018, 06:52 PM
Draker's Avatar
Draker Draker is offline
 
Join Date: Jun 2016
Location: Livermore, CA
Posts: 118
Default

Thanks, folks. I will do a test fit with the skins before riveting the bulkheads. I've also decided to round off those square flange corners. I can't believe that would hurt anything.

I remember when initially prepping all the ribs I squared the flanges on these pieces with a hand seamer. Looks like I may have to bend them back if the angle to the skin is not 90 degrees. Bad assumption based on all the wing work. For every step on the Fuselage, there are lots of other "unwritten" things you can do--the trick is to figure out which unwritten things you need to do and which unwritten things not to.
__________________
Ryan Drake
Livermore, CA
https://stiletto.smugmug.com/RV7
Donated 12/29/2017
RV-7A: Empennage and wing kits complete minus fiberglass, fuselage in progress!
Reply With Quote
  #6  
Old 09-09-2018, 06:53 PM
wjb's Avatar
wjb wjb is offline
 
Join Date: Nov 2012
Location: Half Moon Bay, CA
Posts: 771
Default

Hi Ryan,

Like the others said, just rivet them together. Mine looked very similar, but once you rivet them to the bars, you'll be fine.
__________________
Bill Bencze
N430WB (reserved) RV-7 #74152, tip-up. Engine hung!
Log at: http://rv7.wbencze.com
Defeating gravity one rivet at a time
VAF 2018 donation happily made
Reply With Quote
  #7  
Old 09-09-2018, 07:39 PM
jcarne's Avatar
jcarne jcarne is offline
 
Join Date: Jul 2016
Location: Worland, Wyoming
Posts: 573
Default

Yep the warpage you see won't be much issue. The problem is when the bottom skin goes on because it doesn't conform very well. This in turn will not let the holes on the side skins line up. Definitely round the corners a bit to help with this. All I can say is, no matter what you do you will fight this area to some degree. This was one of the most frustrating parts of the build for me. In the end I had to replace a few rivets with slightly larger rivets. You can use oops rivets to some degree but I like NAS1241 rivets better as they are only enlarged 1/64 of an inch.
__________________
Jereme Carne
PPL
RV-7A Emp. done
Wings mostly done
Working on Fuselage
Finish kit on order
Exempt but gladly paying!
Reply With Quote
  #8  
Old 09-09-2018, 10:26 PM
Draker's Avatar
Draker Draker is offline
 
Join Date: Jun 2016
Location: Livermore, CA
Posts: 118
Default

Great. After some "motivation" with a hand seamer, test fit against the bottom aft skin is... not too bad:





I'll make sure the flanges are the right angle before drilling through the skins, but I'm no longer concerned about riveting these bulkheads together now.
__________________
Ryan Drake
Livermore, CA
https://stiletto.smugmug.com/RV7
Donated 12/29/2017
RV-7A: Empennage and wing kits complete minus fiberglass, fuselage in progress!
Reply With Quote
  #9  
Old 09-10-2018, 09:08 AM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 2,950
Default Bottom skin

Quote:
Originally Posted by jcarne View Post
Yep the warpage you see won't be much issue. The problem is when the bottom skin goes on because it doesn't conform very well. This in turn will not let the holes on the side skins line up. Definitely round the corners a bit to help with this. All I can say is, no matter what you do you will fight this area to some degree. This was one of the most frustrating parts of the build for me. In the end I had to replace a few rivets with slightly larger rivets. You can use oops rivets to some degree but I like NAS1241 rivets better as they are only enlarged 1/64 of an inch.
Thanks for reminding me. Yes, that bottom aft cone skin is really thick. Took a lot of massaging to get the shape right.
__________________
Larry Larson
Estes Park, CO
http://wirejockrv7a.blogspot.com
wirejock at yahoo dot com
Donated 12/01/2017. Plus a little extra.
RV-7A #73391, N511RV reserved (1,800+ hours)
HS SB, empennage, tanks, wings, fuse, working finishing kit
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
  #10  
Old 09-11-2018, 04:00 AM
chris mitchell chris mitchell is offline
 
Join Date: Jul 2006
Location: near Harrogate, England
Posts: 365
Default

To make riveting the bulkhead slightly easier, you can ďsandwichĒ the empennage support bars in between the two bulkhead parts. But this only works on non-punched kits. With the bars sandwiched itís much easier to buck the rivets that otherwise are tricky to get to, especially along the bottom.

Chris
__________________
Chris Mitchell

Repeat offender;
RV-8, QB, built, flown 150 hours, sold;
RV-4 - attempted repair, rebuild and remediation - abandoned and junked ;
RV-4 fuselage and wing kits - both at QB stage;
2015-2018 dues paid!
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 12:20 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.