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Builders Help, Please

W

WSBuilder

Well Known Member
What did most of you do to integrate the lower F-450 longeron into the F-404 bulkhead: Sandwich in between the U-plate and the -404 flange or just rivet against the U-plate/404 web flange stack?
I assume you want a minimal step off the U-plate for skin smoothness so wouldn't the sandwich approach be best? Same question concerning the floor rib, F-415 on the aft side of -404? Also, did you slightly bend the longeron at F-402?
Thanks for any help!
 
pkill said:
Here is a couple Google hits which might give you a lead until Van?s Tech Support opens on Monday ?
pk
Click to expand...

Thanks, PK. These show the exact same challenges I'm dealing with, without answers. I called Van's about this last week and after their obligatory sigh hearing it was an antique -4, I was told to "just make it work." Gee, thanks.
 
None

DSC_0004.jpg


DSC_0003.jpg


My airplane?

Forward angle extrusion is notched, rear is bent, shim sandwiched below. No right or wrong method; builder to choose.
 
F-450

Thanks, Brian. But I was asking opinions on the lower longeron (top-most while in the jig), the F-450 with the 1" flanges and obtuse angle on the very bottom. I think you're showing the 3/4" longeron. I know these transmit a lot of load into the F-404 but the most attention goes to a smooth skin transition. Just looking for some options.:)
 
I can email a few more photos of the area you are questioning. Too much hassle to post. On the side, I cut a step in 450 (table saw). 450 is straight, no bends in either plain, from 404 to firewall. The bottom of 450 does not overlap the bottom flange on front 404 bulkhead, which also has the narrow sheet piece that holds them together at the bottom. I used a gusset at the intersection of 450 and 404 bottom flange.
 
Bill,
Here's what I did on my 4. For what it's worth, It's the way I decided to make it work, you may want to do something different. Did a lot of research before I finalized it and it's the best way I found.
Now hopefully, I can figure the way to insert a picture.

Looks like I'm not having any luck, or I'm to impatient. Send me
and email address and I'll return a couple.

Ross Scroggs
RV-4 #3911
Locust Grove, GA
 
Photos

Hi

Sorry I missed the original post for some reason?

I will look up these parts and try to photograph them tonight.
 
F450 picture

WSBuilder said:
What did most of you do to integrate the lower F-450 longeron into the F-404 bulkhead: Sandwich in between the U-plate and the -404 flange or just rivet against the U-plate/404 web flange stack?
I assume you want a minimal step off the U-plate for skin smoothness so wouldn't the sandwich approach be best? Same question concerning the floor rib, F-415 on the aft side of -404? Also, did you slightly bend the longeron at F-402?
Thanks for any help!
Click to expand...

Hi,

I'm currently at the same stage of construction as you. I found a picture of the F450 intersection (someone elses aircraft) on this forum, hope this helps.

F405.jpg
 
WSBuilder said:
I called Van's about this last week and after their obligatory sigh hearing it was an antique -4, I was told to "just make it work." Gee, thanks.
Click to expand...
Probably won't make you feel any better but depending on who answered the phone this was a typical answer even before -4's became 'outdated'.

I'm about to walk out to the shop and see if I can get a few clear pictures of how I dealt with it.
 
nauga said:
I'm about to walk out to the shop and see if I can get a few clear pictures of how I dealt with it.
Click to expand...
Excuse the trash, I'm drilling new wiring runs.

Is this what you're looking for (minus the FOD :eek:)?

Left side, F404 at the bottom:
2jziut.jpg


Right side, F404 at the bottom:
2eelr8x.jpg


I ground back the vertical web of the longeron to clear the 404 doubler, but not very much. I seem to recall getting advice to do so from Vans, but that would've been years ago. I'll check my log.
 
Correct

Hi

I can confirm Nauga has built it as per plans, I checked mine last night and the plans show the F450 behind the U and the F405 (the dashed line) is the 450 hidden behind the other parts.

Not sure if you know this and not wanting to teach anyone to suck eggs but solid lines are thins on top...... dashed lines things hidden behind other parts.

Another point all this is hidden by the wing root so cannot be seen anyway.

Nauga has done a good job!
 
I agree

WAM120RV said:
Hi

I can confirm Nauga has built it as per plans, I checked mine last night and the plans show the F450 behind the U and the F405 (the dashed line) is the 450 hidden behind the other parts.

Not sure if you know this and not wanting to teach anyone to suck eggs but solid lines are thins on top...... dashed lines things hidden behind other parts.

Another point all this is hidden by the wing root so cannot be seen anyway.

Nauga has done a good job!
Click to expand...

Without a doubt, I would have the most confidence in Nauga's installation. It is definitely the best approach from a structural standpoint. And as you point out WAM, the skin transition over this assembly is hidden. I may install some shims to ease the skin transition so as to inhibit potential skin cracks.

I would add this specific issue on my list of things to look at when shopping for a used -4.
 
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