Section 10 - Tailcone

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	Section Hours: 148.5	Section Status: Complete

July 27, 2006 (10-3 step 1): Sooo… now I have an excuse to get started on the tailcone! 1st step… well actually, the first step is to tap the tail tie down. We don't have a tap & die set yet so I'll skip ahead a bit… 1st step… I'm going to "unbend" the horizontal stabilizer attachment bars. Due to the punching operation during manufacturing these guys are bowed a bit as you can see. I followed the steps in the plans on how to straighten them and it seemed to work well.

Before...

After...

After they were straight I spent some time at the scotchbrite wheel deburring them. The edges were pretty jagged on these things! And due to their thickness it took a little longer than usual to get them smooth.

July 28, 2006 (10-2 step 1): We went and picked up a tap and die set an hour or so ago so I decided to try it out ;-) Here I'm tapping the AEX tie down bar that will eventually become the place where the tail tie down ring will be. I'm tapping first incase I screw it up. We'll eventually cut off about 2" or so when we cut this thing to length. That means the bar is long enough that if you screw up your first attempt you can turn it around and try again simply cutting off the boogered up end.

July 29, 2006 (10-2 steps 1-3): Angela came out and jumped on the tailcone tasks. She started out by deburring the F-1012A&B bulkheads. These are the aft-most bulkheads on the airplane. The vertical tail assembly will bolt to these, and the tail tie down will also attach to them (visible in the second picture). So her next step was to cut the tail tie down bar to shape and get it ready for fitting to the bulkheads. After deburring she got to match drill various holes for attaching the tie down bar.

(10-2 step 4): Angela's next step was to cut the rudder cable angle from some of the .063 angle stock in the kit. After that a couple of #12 holes were put in it. The next step is to attach a couple of nutplates over these holes to locate the rivet holes that will be used to attach them.

(10-2 step 5): Angela got the nut plate holes located in the rudder cable angle. Once the holes were located and drilled, she countersunk them for flush rivets. Here you can see the rudder cable angle (with the nut plate holes countersunk) sitting on the F-1011 bulkhead approximately where it will eventually attach (not in the correct orientation though).

(10-3 step 2): After that she started deburring the F-1011 bulkhead.

August 5, 2006 (10-3 step 2): Got a lot to do today, but unfortunately it doesn't involve the plane. So, I'm going to try and sneak a few things in real quick. We're going to give the proseal on the elevators one more day to cure so I'm going to move on with the tailcone duties. Here I've clecoed, and I'm final drilling the horizontal stabilizer attachment bars to the F-1011 bulkhead.

(10-3 step 3): Next step was to clamp the bulkhead stiffener I cut from one of the 6' J-channels to the bulkhead. There are no holes pre-punched in this so care must be taken to center it and get the top edge 1/4" above the row of holes in the bulkhead. Here you can see I've got it clamped in place. After that I simply flipped the assembly over and match drilled the bulkhead holes into the stiffener.

(10-3 steps 4 & 5): Using the same technique as above I match drilled the 4 holes used to attach the rudder cable angle to the bulkhead. After that I opened up the two 1/8" holes in the bulkhead that the rudder cables will pass through to 5/8".

(10-4 step 1): Angela decided to join in on the fun so she cut the F-1010A horizontal stabilizer attachment angle from some of the .125x1x1 angle stock. This angle will form part of the structural mounting point for the forward edge of the horizontal stabilizer to the tail of the aircraft.

(10-5 steps 2 & 3): We also decided to cut all the J-stiffeners for the tailcone to length. There are 12 of these of varying length and they will run the length of the tailcone providing a mounting point for the skins.

August 12, 2006 (10-4 step 2): I wasn't able to contribute to airplane building today, but Angela did just fine without me. She continued on with the tailcone. Even though she's excited about being on a new section she's come to a conclusion that she doesn't like deburring bulkheads! They have lots of edges ;-) So, after suffering through the F-1010 bulkhead she then clamped the horizontal stabilizer attachment bracket in place and match drilled the 7 holes that'll be used to attach it. This angle bracket is where the front half of the horizontal stabilizer will attach to the tail of the aircraft.

(10-4 step 3): After the F-1010 bulkhead next came the F-1008 bulkheads. (we're basically working from the rear to the front of the plane) This one is big enough that it comes in 2 pieces, a left and right. Angela once again slaved through the deburring process, and then clecoed the 2 sides together. At the bottom joint the F-1085 rudder cable bracket is also attached. Once all clecoed together the common holes were final drilled.

August 13, 2006 (10-4 step 4): Angela continued deburring the bulkheads for the tailcone. Here she's messing with one of the F-1007's.

August 20, 2006: Yesterday Angela picked us up some brackets and 2x4's to make our own saw horses. The tailcone assembly requires a couple of these, plus we could use some extra "table" space. We could buy them ready made for about $25 each (the cheapest we found) or we could make them for about $9.50 in materials (a pair of brackets, and two 2x4s). The tailcone requires 38" minimum height on these so we cut the legs to 36". The horizontal is the leftover piece of a 10' 2x4 after 2 legs were cut from it. The height winds up being about 38-3/8". I only got one of these done this morning... We have materials to do 3 total.

August 21, 2006 (10-4 step 4): No pics tonight… I finished up the saw horses, while Angela continued deburring bulkheads. Have we mentioned how much she likes deburring ;-)

August 27, 2006 (10-5 step 3): This morning Angela duburred all the ends of the F-1047 fuselage stiffeners.

(10-5 step 4): After the stiffeners were deburred we put together this little contraption to mark the rivet centerline holes. It's a 2x4 scrap piece with a spacer and a pen taped to it… basically its just whatever was laying around that provided the correct spacing for the line we needed to draw! We just rest the 2x4 against the edge of the stiffener, and the pen is spaced perfectly 5/16" from the edge. Slide it down the length of the stiffener and we've got our rivet centerline!

(10-4 steps 4 & 5): I jumped in and clecoed the F-1007 frame together and final drilled the common holes. After that I used a unibit to open up the indicated holes to 5/8".

(10-5 step 1): Next I began deburring the F-1006 bulkhead pieces. While doing this Angela started setting up to begin the pre-assembly of the tailcone… Well, I just couldn't let her do that alone so I didn't get very far with the deburring!

(10-7 step 2): So… now that my attention was thoroughly diverted away from my deburring duties, Angela & I teamed up to cleco the bulkhead frames to the bottom skin of the aircraft tailcone. Once the bulkhead frames were in place (ok, all of them except for the one I haven't finished deburring yet) we slid the two F-1047F stiffeners into position until the rivet marks on them were visible with the last hole on the skine. Once in place, I clamped it still and match drilled the hole. A quick cleco to hold it in place and we were done for the day... gotta go to work... again... Way too much OT lately!

September 1, 2006 (10-7 step 2): An 11 and a half hour day at work today… ugh… even though I got home about 10:00, I just felt the need to do something on the plane. So I popped out in the shop for a bit and match drilled the first of the two F-1047F stiffeners with the lower skin of the tailcone. This is the first of the twelve stiffeners we cut a little while ago. These will go from front to rear all around the circumference of the tailcone. Once I had the 50 or so holes drilled, I was ok... I could now call it a night.

September 4, 2006 (10-5 step 1): Today has turned out to be frustrating! Finally a chance to devote some time to building and 30min into deburring I come upon this… This is the lower portion of the F-1006 bulkhead. I pretty much had the entire thing deburred when I noticed these cracks in the lightening holes. These are definitely from the manufacturing process, and there is one in the exact same spot on all 4 lightening holes... uugghh! A quick search of the Matronics forums and apparently I'm not alone. It seems the solution ranges from a replacement part from Van's to a suggestion from Van's to stop drill the crack(s), and then open them up and smooth them similar to the opening between two flanges. I'm not real keen on the fix-it idea... especially since there are 4 cracks. Oh well, I'll check for more and then move on to something else [sigh].

(10-7 steps 2 & 3): I checked over a few more parts and didn't find any additional cracks… hopefully I won't from here on! So, on to other things. Next up, I finished match drilling the F-1047F stiffeners (I did one the other night, and still had the second one left). After that, I slid the F-1047G stiffener in and match drilled it. This one goes right down the center of the bottom skin of the tailcone.

(10-7 step 4): Next I clecoed in the belcrank ribs and final drilled them to the F-1007 frame (the whole tailcone assembly is upside down right now). Interestingly the plans don't mention final drilling the skins to the belcrank ribs. I made a quick check a few pages ahead and didn't see any mention of it in later steps. I think for now instead of spending a lot of time trying to figure it out I'll just mark the holes as needing to be drilled and move on. If I get to the teardown stage and they still haven't been drilled, I'll handle it then.

(10-6 step 2): I wanted to get one of the side skins clecoed on, but I soon realized I needed to use the skin to measure my bend in the longerons. So, instead I located the longerons, cleaned them off and then marked them for their bends (I'm going to bend them before cutting to length incase I screw one up) The plans call for padding your bench vise with aluminum prior to clamping in the longeron. I had been wanting to reface the pads in the bench vise so I used this oportunity do do something about it. I cut some of our scrap aluminum sheets to fit the pads, duburred them and then scuffed one side. I then cleaned both them and the bench vise pads with acetone. After that I mixed up some JB Weld, spread it on the scuffed side of each of the sheets, placed each sheet in the bench vise glueing it to the bench vise pad, and then clamped the bench vise down on them. I'll let this sit overnight and then I should have some nice smooth pads in my bench vise.

September 5, 2006 (10-6 step 2): I wanted to get the right side skin clecoed on tonight so I needed to get the longeron bent. This was definitely an exercise in patience! Using the mark I made earlier as the bend point the process went as follows… place the longeron in the bench vise with the mark just sticking out of the side. Pre-load the longeron in the bend direction and then with a soft mallet strike the longeron close to the bench vise... and then strike it again... and again... and again... and again. You see, what we're trying to accomplish here is bending a piece of angle-aluminum in the direction of one of the flanges. Not exactly an easy thing to do. It turns out to be a tedious process because not only does it bend in the direction intended, but since the flange in the direction of the bend doesn't exactly want to compress on itself, it forces the longeron to bend in another direction. So, while you're beating the bejeezus out of it, its bending in two directions... one you want, one you don't. Anyway, the gist of it is clamp it in, bend it in the direction you want, clamp it in another way, unbend it in the direction you don't want it bent, remove it and lay it against the skin to check your progress... and then repeat. Keep doing this until it's finally bent the amount needed, while still being straight along the other flange. I think I'll wait and do the other one another night :-)

(10-7 step 5): Now we're getting to the stuff that shows progress! Here I slid the three stiffeners that go down the right side of the tailcone into place. After that I also "massaged" the flanges of the frames and bulkheads to better mate to the skins.

(10-7 step 6): After the stiffeners the side skin was positioned, and clecoed into place. After it was clecoed on I lined up the marks on the front edge of the stiffeners with the foreward-most holes and went ahead and match drilled them (the 3 clecos along the side skin in the foreground). Next time we're set up to go ahead and final drill all the holes in these stiffeners.