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Crawling into the tailcone...???

txaviator

Well Known Member
I've been searching the forums for specific tips on how to crawl into the tailcone without damaging the bulkheads, bottom skins, etc. Nothing real specific on what you folks have done?

I'm on the last pages of the fuselage kit and expect to jump into the finishing kit within a week or so. Thinking ahead (my avionics are on the way) I've been wondering what folks did whenever they needed to crawl back into the tailcone? By the time I get to this point, I'll be on the gears and will build a tail support to hold all of that up. The bulkheads surely don't seem strong enough to simply lay sheets of plywood over them!?

I spoke to a local -12 builder a few months ago, and they had cut foam pieces to lay between the bulkheads (much higher than the bulkheads, then it compressed) then laid plywood on top of that. However, I think their fuse was still on tables- but I am not too sure about that.

Any thoughts or suggestions? I sure don't want to screw something up this late in the build. I'm 5'11" and 215#, so it may be interesting crawling in and out, to say the least :confused: I'm also hoping there's a good 'construction beer' shelf back in there too? I'd better crawl in with my cellphone in case I can't get my big #*@ back out, lol. :eek:

Take care,
 
I was wondering about that issue. Could you leave off the top skins or at least only cleco them until the wiring is laid? Hopefully I'll be able to integrate that into the build at the time since I'll be ordering the finish kit with the wings and fuse.

Bob
 
I don't play one [RV-12 builder] on TV and I didn't stay at a Holiday Inn, last night. That said, for the other RV models, Vans recommends that you fabricate some temporary wooden floor boards so that you can rivet the top turtle deck skin on and do other work back there without damaging anything.
Naturally, I overdo everything. I figured why do a shoddy job on this, as I will need to get back there for the annual condition inspection every year. I glued two layers of the thin finish plywood that Vans uses for shipping boxes, then cut the temporary floors to size. I sanded the edges round [makes them easier to install and remove] and coated them with 2 coats of varnish [A friend had given me what was left of a gallon can]
I made cardboard templates first to test the fit. Best to make these BEFORE you rivet the turtle deck skins on. Round all the edges so that you can get them in and out with the turtle deck on. See photo below. These are for an 8A.

tailconeviewofbatterybuh.jpg


Multiple pieces will be easier to install and remove. If you plan to save them for future use, be sure to make cut outs for the elevator bell-crank and any other obstructions which will exist in the finished tail-cone.
Hope this gives you some ideas.
Charlie
 
I used wooden platforms to access the back of the RV-8 when I built it, and found them uncomfortable and worrisome as to the point loads on the bulkheads.

On the -3, we did something different, and it worked out great! We had a large stack of moving and hospital blankets laying around, and we used those to fill the space between the bulkheads on the "floor" of the fuselage, then when they were as thick as the bottom of the bulkhead openings, we added a few more to make a continuous soft floor on which to lay (or is it lie - I never get that grammar right!). Very comfortable, and the loads were well distributed. Easy to install and remove as well - you just grab and pull - no way to damage the structure with hard sharp corners.

It worked well for us.

Paul
 
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snipped I'm 5'11" and 215#, so it may be interesting crawling in and out, to say the least :confused: I'm also hoping there's a good 'construction beer' shelf back in there too? I'd better crawl in with my cellphone in case I can't get my big #*@ back out, lol. :eek:

Take care,

The trick is to use some of that beer as a bribe to get a smaller friend to crawl in there for you! ;) If you have grandchildren, candy works and is cheaper than beer. Besides, now they will like you better than grandma!

Got to say, Paul's suggestion is a lot less work than mine. I did not have any worries about stress on the bulkheads, as my wooden flooring also contacts the lower longerons along the sides.

Charlie
 
Tailcone access

Make a platform out of crate wood. Block it up on the bulkhead so it doesn't rest on the control cables.
This will get you access as far back as you need to go to build the plane.
CTT_3288-L.jpg


Tony
 
Bean bag chair

I have one I use weekly at work. I can throw some wood over it to. A couple of bags of packing peanuts with wood overlay does the trick to. Speaking of bean bags, I also have a vanity mirror that is carpet taped to a small bag of "peanuts". It stays just how I lay it no hands.
 
All you will ever need access to back there is the ADAHRS stuff. I was able to reach that stuff without ever leaving the baggage area floor. I did spend some uncomfortable minutes with the edge of the rear bulkhead digging into my back, but I never needed to put any pressure at all on the relatively weaker skins and formers back there. I did support the tail, though, with a scaffold I picked up at Lowes.

tailcone.jpg


scaffold.jpg
 
Support the tail!

... I did support the tail, though, with a scaffold I picked up at Lowes...[/IMG]

Tail support is very good idea.

The slow teeter-totter fall onto the unsupported tail would have been interesting to see from the outside ("Dad, that airplane is trying to fly without an engine!"); the uphill and backwards crawl was less so.

Add the time pondering the damage you just heard, the time spent wondering who saw your "first flight", and actual repair time to the time spent explaining the damage, and the 15 minutes arranging the tail support is a no-brainer. Of course, that's after the fact.

YMMV
 
Foam on the skins between the bulkheads and a board laying on top of that is how I did and do it on my 7. It works for my fat butt. May have to be more careful with the 12 however since its construction is lighter.
 
Foam on the skins between the bulkheads and a board laying on top of that is how I did and do it on my 7. It works for my fat butt. May have to be more careful with the 12 however since its construction is lighter.

I just spent some time in the tail of my -3 recently and this is what I did also. Lots of smaller peices of styrofoam "board" with some thin wood on top (the real thin backing board type stuff) with a bunch of blankets/padding on top of that.

BTW: The time I spent in the tail was to modify it to carry my ski's (documented at Ski Truck Epilogue) - can't wait for the ski season to start!!!
 
If you follow VANs directions while you build there should be no need to crawl into the tail cone. I didn't need to for my build and everything worked out.
 
If you follow VANs directions while you build there should be no need to crawl into the tail cone. I didn't need to for my build and everything worked out.

This may be true during the build process (I'm not a -12 builder). If talking about after the build, there is a need for inspection and maintenance back there. Probably could be done with inspection panels though. Inspection panels would kind of take the adventure out of the event though!! :D
 
If you follow VANs directions while you build there should be no need to crawl into the tail cone. I didn't need to for my build and everything worked out.

I have followed the plans to the letter...never strayed out of order at all. But I'm thinking there is a need to get back into there, after the main plane is built, to install some of the Skyview avionics components? As some have pointed out, you don't have to go in there very far, but I will need to enter the tailcone a few feet for component installation. This is per the plans, to install the ADAHRS box, I think (**edit: yep, just as Dave points out in his post and photos)...I'm not that far yet, but there is an ADAHRS bracket at the very top of the tailcone- a few feet in, that gets something hooked up. I'm hoping that I can kind of reach that from the cockpit, as did Dave and others.

Thanks for the replies and ideas, everyone!
 
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What we did: It turned out not to be too big of a problem crawling back there. We layed down strips of foam on the closest tailcone bulkhead and then place a board on top of that. Since we had already run our control cables we were careful to place them between the strips of foam and not squish them into the bulkhead. There is also a plastic control cable guide that is attached to the bulkhead, and it sticks up above it about a half inch. We were careful not to lay the board on this, and were also careful not to shift the board when we were laying on it.

What we should have done: If you can, leave the tailcone off as long as possible. It will be alot easier to access the tailcone and the fuselage section if they are seperate.

Support your tailcone before you climb in it on a sawhorse or other retaining device!!
 
Foam Blocks

I made Styrofoam to put in the tailcone. I used 1" foam,stacked to 3 inches.
I used white glue and let the panels dry under weigh of books or wood for a couple or more days.

It is easier if you find 3" foam but this is what I had.

Cut to shape once the foam is ready on a band saw, put the foam in and do what you need to. DO NOT fly with this foam in the aircraft.
 
This is per the plans, to install the ADHARS box, I think
I failed to mention that I followed the advice of a rather sharp fellow builder who suggested that it would be easier to mount the ADAHRS box to the mounts and then rivet the whole assembly in at once. He was absolutely correct!
 
I took a different approach, I added 4" inspection ports one the side near the tail (for counter weight access) and along the bottom centerline for wear plate access and autopilot servo inspection.
 
I failed to mention that I followed the advice of a rather sharp fellow builder who suggested that it would be easier to mount the ADAHRS box to the mounts and then rivet the whole assembly in at once. He was absolutely correct!

Sounds like GREAT advice, but I have already riveted the mount to the top of the fuse. I'm not where I can view the plans, but if IIRC, that's just held on with a 4-6 rivets. Sounds like I'll remove the bracket if able, mount up the ADAHRS equipment, then re-rivet!

I should have left the tailcone off, but again, I just followed the plans. If I build another one I'll leave the tailcone off for sure until some of these steps are done!

Thanks everyone.
 
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I had my grand daughter crawl in the tail cone and secure the wiring and clean up a few things. I let her sign her name on it with a marker. :D
 
I had my grand daughter crawl in the tail cone and secure the wiring and clean up a few things. I let her sign her name on it with a marker. :D

Can you fly her down to Arlington, TX? :D Sounds like your idea worked better than anyone elses! That was a GREAT idea!

My grandfather owned an airport and specialized in rebuilding severely damaged Cessna's. I was the skinny kid designated to buck rivets in the tail areas of the Cessna fuselages. Of course we didn't even think to use hearing protection back then, which is why I still have a terrible ringing sensation in my ears, to this day :(
 
Great suggestions! I'm going to combine a few of these together. I have loads of packing peanuts laying around. And I have a stack of furniture moving pads. I'm going to make up some "peanut bags". I can toss those it to start to level out all the odd spaces. Then finish with some pads.
 
Child Labor

I looked at something yesterday back in the tail I wanted to do.

It can wait till Saturday. Then 1 of my 3 little ones can earn their ice cream.;)

Regards,

Scott
 
Great suggestions! I'm going to combine a few of these together. I have loads of packing peanuts laying around.

Man oh man ! why didn't this thread happen 2 years ago ?!

I finally had to start the install of the remote compass in the tail cone. I took a plethora of packing peanuts and very loosely filled two garbage bags. Then I grabbed an old bed sheet (aka now a paint drop cloth). I draped the sheet on the floor of the RV-8, dropped in the two bags of packing peanuts, and covered them over with the rest of the sheet.

SERIOUSLY COMFORTABLE ! No more being poked by the front seat crotch strap bracket, the seat belt brackets, or the rear stick mount ! Even shimmying up to the front rudder pedals is relatively comfortable.

20130104-145740-452x640.jpg
Now, does someone have an automated tool retrieval solution ?
 
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Tail Access Door ?

To get access to the tailcone would be much easier with an opening like the one in the Mooneys tail. Anything against installing an access door like this one into the RV9 tail between bulkheads F707 and 706? :rolleyes:

Any thoughts from the experts?

regards Pit
 
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I'm not an expert and I assume you're talking about the RV-9, but cutting any access or inspection opening in the fuselage will inevitably weaken it. Whether or not it weakens it enough to seriously compromise the safety of the airframe is really a question for Van's engineers, and their response would probably be that they haven't designed it that way, haven't tested it, and therefore you are on your own.
I was not too concerned about splitting the baggage bulkhead in the RV-12 to allow easier access to the rear fuselage, but there is no way I would cut any additional access holes in the fuselage skin, especially in the vicinity of the stabilator. I would rather know that the tail will stay on for the loads it was designed for, than hope that it will.
 
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Blocks of soft scrap foam rubber given away from a local mattress maker. Yes, prop up the tail.
 
Good ideas, I wonder though about the foam/packing materials. Wouldn't that put he weight of my 200# body on the skins? Would it be better to distribute that weight on the bulkheads?

The reason I'm asking is...My tailcone is still separate, haven't started the fuse yet. I did discover an issue with a rivet that one of my helpers put in at the top of the f-1209 bulkhead. The rivet was probably forced in and pushed the bulkhead tab away from the skin, so that when the rivet was set it was not set holding the skin and the bulkhead together. I'll need to get back there (second bulkhead back from the front end) and bend the tab back to reset the rivet.

I've been leery of putting my weight in the tailcone to fix it.

Bob
 
Bob,
I just laid the seat and backrest cushions in the tail cone and got the job done. Beads or foam will work fine too. The cone will carry any fairly uniformly distributed load without any problems. I think the main thing is to protect the bottom J stiffener from being damaged, and to ensure the whole thing won't tip up when you crawl in the back. It's really not a big deal. If you're anything like me, you are more likely to damage yourself than the aircraft.
 
Tailcone access

One idea is to make a platform out of some of the scrap crate lumber. The far end is blocked up on the bulkhead with openings between the blocks for the control cables so they are not forced onto the bulkhead.
CTT_3288-M.jpg


Tony
 
As the starter of this thread, way back when, I can now tell you it was no big deal! I used some old pillows between the stiffeners and cables, and laid some short 1"x8" boards out across the bulkheads. A sawhorse with a blanket on top of it went under the tail, and everything worked fine. As someone else mentioned, getting in and out was the most laborious part! Think out your tools, materials, spare beers, whatever, before you crawl in :)
This saves multiple in/out trips into the tailcone. It really was NO big deal. Kind of reminds me of the fear me (and lots of others had) on bending the longerons correctly. Instead of the barbaric hammer and vice method, buy the longeron bending dies. Simple, accurate, and on to the next step in the plans!
 
I never had to climb into the tail end of an RV, yet...

But, I have climbed into the tail of a few Cessnas and Pipers.

The way I did it was to put heavy moving blankets like the ones you rent from U-Haul, down along the webs and control cables, then lay the thick pink insulation foam sheets down on top of that. Those foam insulation sheets are very sturdy and will distribute your body weight without damaging the web flanges.

Word of warning: empty your pockets first. The best way to loose a screw driver is to put it in your back pocket, then climb into the tail of an aircraft.

You tend to find it again at the most inopportune time.
 
Bob,
I just laid the seat and backrest cushions in the tail cone and got the job done. Beads or foam will work fine too. The cone will carry any fairly uniformly distributed load without any problems. I think the main thing is to protect the bottom J stiffener from being damaged, and to ensure the whole thing won't tip up when you crawl in the back. It's really not a big deal. If you're anything like me, you are more likely to damage yourself than the aircraft.

Thanks for the comments!

I was going to set the tailcone on the garage floor (on those interlocking floor pads) and then crawl in.

Right now the tailcone is hanging from the garage ceiling...

Bob
 
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