Empennage / Front Bulkhead Riveting - 10

MSEYEFLY · #1 07-10-2018, 07:44 PM

I?m finishing up the tailcone riveting on my 10. The plans call out many times not to drill the front bulkhead/skin (to be matched when joining to the fuselage). I can understand not match drilling the skin/bulkhead.......but shouldn?t I drill and countersink a hole in the left/right longeron that matches with the skin/front bulkhead holes? If all other longeron holes are drilled/countersunk (with the few exceptions for the rear tail cone), shouldn?t the longeron hole that mates with the bulkhead/skin also be drilled and countersunk (and skin dimpled) before I trap the longeron in the tail cone via riveting? Any help is appreciated.

Bill.Peyton · #2 07-11-2018, 07:15 AM

It?s been too long for me to remember, but when in doubt, read ahead. You may find the answer there

MSEYEFLY · #3 07-11-2018, 07:28 AM

Thanks Bill for responding. Problem is instructions for this sections construction come with the fuselage kit (which I haven?t ordered yet) and I didn?t get a confident answer when I spoke with Van?s. Just want to check with others who have been through this part of the process.

ppilotmike · #4 07-11-2018, 08:45 AM

Mark,

You need to order the digital set of plans from Vans. It comes with all sections, in PDF format, loaded onto a thumb drive. It's very convenient to have all the plans at your finger tips. I believe the holes you are speaking of, at the foremost end of the tail cone top skin, get match-drilled with the top in place, which is why it's left undone at the point you're at. However, since I'm not sure exactly which holes you speak of, you should order the plans and check for yourself to be sure.. KPTR my friend!

bluskydreamin · #5 07-11-2018, 10:53 AM

Hi Mark,

I sent you a pm if you want to visit my build. I'm just down the road from you and on the finish kit...

Mike is spot on with the digital plans helping to give you the entire picture so you can "see into the future."

MSEYEFLY · #6 07-11-2018, 08:15 PM

Thanks Mike/Jeff for the advice. I?ll take your advice Mike and order the full plans. I really appreciate both of you taking time to respond!

Jeff - It?s awesome to know you are close by and I would love to take you up on your offer. As a first time builder, it?s great to know someone close by working on the same project!! My daughter is a junior at UF so I?m there quite frequently and I?ll give you a call to link up.

Mark

Tassie · #7 07-11-2018, 10:21 PM

Quote:

Originally Posted by MSEYEFLY

shouldn’t the longeron hole that mates with the bulkhead/skin also be drilled and countersunk (and skin dimpled) before I trap the longeron in the tail cone via riveting?

Getting back to your original post, you definitely want to countersink the longeron holes in question. For the skins, your choices are (a) drill #40, debur and dimple the holes that overlap the longerons now, or (b) leave enough rivets out along the longerons so that you can stretch the longeron away from the skin and dimple the last skin holes that overlap the longerons after match drilling with the fuselage.

I don't think you'll find anything in section 32 about the holes in question, I certainly didn't, this is one of many plan gotchas and well done to think about these holes in advance.

Now, if you are doing a slow build fuse and have your fuselage plans, go to page 32-6. There are two AN426AD3-6 rivets in the callouts, these are the only rivets that go in the overlapping of three skins - bottom, mid side, and tailcone. The tailcone attach instructions call for you to assemble everything, match drill the attachment points, pull everything apart, debur and dimple. These two holes are pretty much impossible to dimple if you have already assembled the fuselage per the plans, there's just not enough room to peel the skin back and the bottom fuse skin is really too thick to use pop rivet style dimplers. When you get to this point, think about dimpling these two holes before assembly, on both the bottom and mid side fuse skins (and the tailcone), it'll save you a whole load of angst. Another option is to leave out more rivets along the mid/bottom skin overlap, but that still doesn't help you to dimple the last hole in the mid side skins because the bottom skin is in the way.

Regards,

Adrian

flion · #8 07-12-2018, 08:10 AM

I have revision 2 of the plans and they tell you to machine countersink all the skin holes in the longerons except for the gap cover holes (Page 10-16, step 1). This would include the forward-most hole, in common with the F-1006 bulkhead. Step 3 has you dimple all the holes in the skins with a number of exceptions, including the F-1006 common holes. This is a confusion which may have been fixed in later versions but can be approached in two ways, whichever suit you.

The first is to go ahead and dimple the skin to match the longeron and dimple the corresponding skins to match later in sections 32 (joining the tailcone) and 43 (installing the cabin top - along with the top skin). This is probably the most natural thing to do.

The second is to neither countersink the longeron at this location or dimple the skin. If you read section 32, the forward longeron near this location is not countersunk. Instead, the forward sides and top skin are countersunk for rivets, and you could employ the same technique for the holes where the aft longeron meets the F1006. A variation, for people who riveted the aft skins before discovering the problem, is to countersink the aft skin and dimple the forward and top skins to fit over it.

Either method should be fine. The top skin, which is the overlying one, is thick enough for countersinking so there is no strength issue. I think dimpling looks more natural as the rest of that line is dimpled, but it's not going to be really visible on a finished airplane. Your choice.

ppilotmike · #9 07-12-2018, 09:14 AM

Quote:

Originally Posted by flion

I have revision 2 of the plans and they tell you to machine countersink all the skin holes in the longerons except for the gap cover holes (Page 10-16, step 1). This would include the forward-most hole, in common with the F-1006 bulkhead. Step 3 has you dimple all the holes in the skins with a number of exceptions, including the F-1006 common holes. This is a confusion which may have been fixed in later versions but can be approached in two ways, whichever suit you.

The first is to go ahead and dimple the skin to match the longeron and dimple the corresponding skins to match later in sections 32 (joining the tailcone) and 43 (installing the cabin top - along with the top skin). This is probably the most natural thing to do.

The second is to neither countersink the longeron at this location or dimple the skin. If you read section 32, the forward longeron near this location is not countersunk. Instead, the forward sides and top skin are countersunk for rivets, and you could employ the same technique for the holes where the aft longeron meets the F1006. A variation, for people who riveted the aft skins before discovering the problem, is to countersink the aft skin and dimple the forward and top skins to fit over it.

Either method should be fine. The top skin, which is the overlying one, is thick enough for countersinking so there is no strength issue. I think dimpling looks more natural as the rest of that line is dimpled, but it's not going to be really visible on a finished airplane. Your choice.

Well that explains why I don't remember having an issue in this area of my build. I guess my paper plans were up to date.

MSEYEFLY · #10 07-12-2018, 05:00 PM

Patrick/Adrian - Thank you for taking the time to reply. You?ve given me good options and I?m going to follow thru with countersinking and dimpling now. I see now I need to tap into this forum as a resource more often. I appreciate the time, ideas and help!!!