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Tip Up F-774 Front Rivets

boom3

boom3

Well Known Member
I'm hoping to rivet the front of the F-774 tip up skin and there seems to be no option at this point other than blind rivets. (I cannot buck the 3 inside the frame area)

I've seen other planes with blind rivets in this area but where do I find longer ones? I've only seen the MK-319-BS at Vans and it is way too short.

Ideas? Thanks!

774a.jpg


774b.jpg


774d.jpg
 
I haven't riveted that skin on yet, but in anticipation of this problem I prepared those holes to take CherryMax rivets (CR3212-4-4 most forward, -4-3 for the next two, IIRC). The thing about them though is that they are very long before pulling, so I had to notch out the big angle bracket quite a bit before I riveted it in. Looks like you did that too, but you'll have to determine if your notches are deep enough for these particular rivets.

Good luck!
 
I haven't riveted those yet, but in anticipation of this, I also haven't riveted the big honkin' angle piece in place that blocks access to the shop heads (don't have the plans handy, so can't give the part #). I believe I should be able to rivet the skins in place with regular AN426s, then the angle to the bulkhead and the cross-member, then whatever else is around there, no?
 
Flying Scotsman said:
... I believe I should be able to rivet the skins in place with regular AN426s, then the angle to the bulkhead and the cross-member, then whatever else is around there, no?
Click to expand...

Yes, I think so. For me it was mainly a convenience factor of being able to finish up everything in that area, do interior paint, plumbing, wiring, etc. while there's still good access without the skin in the way. But that's certainly not the only way to go. Lots of possible ways to paint yourself into a corner here, but also lots of possible ways to avoid it. Unfortunately, boom3 has already riveted his angle brackets and most of the skin, so that is his current situation that needs to be solved. Hopefully there's some flavor of pop rivet that'll work.
 
Angle last

For anyone who hasn't got to this point yet the instructions have you rivet the skins before putting the angles in for this very reason.

Looks like cherry rivets will be needed in this case.

Peter
 
Those cherry max rivets are 1/8 rivets. They wont work with out modifying the holes and dimple (or countersink).

I will be in the same predicament soon, and I have yet been unable to find a 3/32" pop rivet that has a depth greater than 1/8th. There must be something out there.
 
Or...

There's also the 3/32" Avdel CCCS-03-04 which has a grip range of .126-.250". It has a 120° head, but it may work.

Hanson Rivet lists the shear and tensile for the CCCS-03-04 as 230 and 280 pounds respectively.
 
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I'll email Vans and get their input too. I'll share that info as soon as I hear back.
 
jmjula said:
Those cherry max rivets are 1/8 rivets. They wont work with out modifying the holes and dimple (or countersink).
Click to expand...

That's right... I forgot. I drilled and dimpled mine for 1/8", but boom3's are already dimpled for 3/32". Ughh...

So maybe the CCR264 "nutplate rivets" would be a good solution. I actually don't think that tensile strength would be much of an issue here, especially given that there are also two #8 screws right above securing the skin to the roll bar. But I'll be curious to hear what Van's says.
 
If I'm not mistaken the CR 3212-4-6 work perfectly there. I used a couple of those further forward on places that the QB folks forgot. Those holes too were in locations where I could see 'em only w/a mirror and could not buck them dependably. I countersunk the holes at 100 degrees (after I drilled 'em out to #30) in the fuse side/ canopy deck and the 3212's fit perfectly. Other than a tiny hole in the center, they fit as well as solid rivets. I bought extras of those rivets to put in the F-774 locations you're talking about.
 
Grip length

Rupester said:
If I'm not mistaken the CR 3212-4-6 work perfectly there.
Click to expand...

Be sure to check the CherryMax grip length chart (or use a gauge). CherryMax rivets are very particular about their grip length ranges. I think -6 is too long here. I could be mistaken so don't take my word for it, but be sure to check for yourself.

Gotcha: Beware that the dash number of a CherryMax rivet is not the same as the dash number of the solid rivet that it would replace. The dash number of a solid (AN426) rivet specifies the overall length of the rivet before squeezing/driving it. The dash number of a CherryMax rivet specifies the maximum grip length.
 
Since I have the cherry max rivets ordered, I may still be able to use them by drilling to 1/8, dimpling the F-774 skin and machine countersinking the side skin and longeron.

(Kind of like the empennage gap cover F-794A, only those are #6 screws.)

I'll see what Van's says.
 
Just got an email back from Van's and they said, are you ready for this....?????

3/32 blind rivets are what you'd need. Any would do, but we don't sell them in that length, and they're not commonly available. Try someone like

http://www.gen-aircraft-hardware.com/default.asp

I think I'm going to look into those nut plate rivets as they are 3/32 and I won't have to drill, re-dimple or countersink.
 
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HA! It's like they've been following along.

I like to support Tom (VAF: GAHco) any chance I get, but you may have to buy them in larger quantities than you'll need. If so, I would be interested in buying a few from you to help reduce your overall costs.

Otherwise Wick's sells them in smaller quantities.
 
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Here is a trick-Modified Cherry Max

Here is what I did.

I knew this area was going to be problematic. I cut reliefs in the 3/16 angle where the shop head of the rivets would be (as the original poster did). I drilled and countersunk the longeron angle to accept the #3 rivet dimpled skin per the plans. I opened the hole up to 1/8" but left the #3 dimple in the skin as is. I then took a 1/8" (#4 rivet size) Cherrymax rivet of the right length and removed the mandrel. Filled down the head of the Cherrymax to the same head diameter of a 426 #3 rivet, reassembled the Cherrymax with the mandrel. Now I had a #3 head on a 1/8" diameter Cherrymax to set in these "challenged" locations. Worked great. Better then countersinking the longeron to accept a #4 dimple in skin.

Cherry used to make exactly this type of rivet. I don't know if they still do or are available affordability in small quantities.

So improvise.................
 
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Ok based on Van's response...

"3/32 blind rivets are what you'd need. Any would do, but we don't sell them in that length, and they're not commonly available."

The only 3/32 blind rivets I could find that were long enough were the CCR264SS-3's. Thanks for the suggestions!

Due to the thickness of my material and recommended rivet "Grip lenth" I elected to use CCR264SS-3-3's for the rear two and a CCR264SS-3-4 for the front one. (You can buy them individually from Wick's)

Anyway I'm happy for now and can't wait for the next drama to come along on this project.:eek:

blind1.jpg


blind2.jpg


Although they look alot like solid rivets from this angle, they aren't.

blind3.jpg
 
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