Turtle deck forward and aft bulk head fabrication

Sorry for no post lately I went on a great vacation with my family for 8 days. Anyway this post is a three day roll up of yet more turtledeck fabrication. I started off wednesday night (11jan12) by laying in some tape at the aft bulk head to mask the line so I could lay up a couple of tapes for the turtle deck flange. I also cut the straight line on the turtle deck tails so that they could be re-glued straight as to not chaffe the fabric so the plans say. After I masked the turtle deck side I laid up 3 layers of 5.8 oz 282 carbon fiber. I also clamped and taped the cut lines back together with 2 layers of 282.

The next day (thursday 12Jan12) I marked the cut line on the out side of the turtle deck and cut the mask line using my dremel tool being careful not to cut into the new flange. This worked ok, not quite as smooth of a line as I wanted but it worked good enough. I also worked on ideas for the forward mold.

Saturday (14jan12) I decided to work on the mold for the forward bulkhead. I used my mold cut out blank and taped up the edges then I cut the same shape out of 0.016 2024-T3 I had laying around. I used the sheet metal because it gives a nice and perfect glossy finish. I then used my mid bulk head blank and trimmed it also radius the corners for to complete the “hole” space. and finally I used a block of wood that I taped with packing tape so that it wouldn’t stick. This one was a bit trickier since it had to be set at an angle and then screwed down into the wood of the cut out. I sandwiched everything together with dry wall screws and ratchet strapped in place which can be a big pain in the ass because of the angles/tapers of everything. I finally got it sitting in there nice and neat and laid up 3 layers of 5.8 oz 282 carbon graphite bi-weave into the mold.

Sunday (15Jan12) I removed the mold and I was pleasantly surprised to find a perfectly molded beautiful forward bulk head. I trimmed it up and sanded the corners to a nice smooth radius. It fit well. I threw my canopy up on the fuselage to see how it fit and it fit well but then I noticed that I will be making a new canopy sheet metal since I tilt the turtle deck aft the metal no longer is long enough (see below picture) oh well, I’m replacing everything else might as well replace that too. I then spent most of the day building the mold for the aft bulkhead. This was done similarly to the forward bulkhead but instead of wood for the center piece I used a old plastic tub that just happened to be the right diameter. I again used sheet metal and tape for mold release. This time I laid up 4 layers since this one would be supporting fabric tension. The flange will be now 7 layers thick so nice and stiff hopefully. I spent the rest of my time cleaning up and playing around with the elevator trim cable since it came in the other day.

Time spent over 3 days: 20 hours
Total time spent: 1044 hours

Rib stitching and taping the lower right wing, turtle deck mid bulk head flange

Today I spent most of the day simply rib stitching the lower right wing. The long rib took about 40 minutes to complete where each smaller rib took about 20 minutes with breaks for my sore fingers it took me most of he day. After the stitching was completed, I started to tape the top of the wing’s ribs and spar. After all that was done I decided to work on the turtle deck some more. I used my wooden cut out of the mid section of my mold and I traced the correct location of the bulkhead while it was installed on the fuse. I then covered the wooden cut out with plastic for a releasing agent and held everything in turtle deck with straps. I laid in 2 layers of 5.8 oz 282 carbon graphite bi-weave and let it sit overnight. In the morning I removed the wood which release fairly easily and trimmed it up. And What do you know it fit perfectly. I will need to lay at least one more layer in there to stiffen it up a bit but I am happy with the results.

Time spent today 10 hours
Total time spent 1024 hours

Covering the lower right wing

Yesterday and today I worked on covering the lower right wing. I started by installing anti-chaffe tape on the the ribs and I double checked all the push pull tubes and bearings to make sure I didn’t forget anything. I then pre-glued all the edges that I was going to stick the bottom fabric to and then laid the fabric on just like the top wings. I trimmed the extra fabric off and then stuck the fabric into the dried yet tacky glue and then ironed it down. Once every thing was ironed down I added glue to all the pre-glued areas I just ironed. Once everything was dry I ironed it down to 250 deg F. After it was ironed I cut diagonals on the lower wing plywood inspection hole and ironed the fabric to the shape. The diagonals relieved the stress so that the fabric could take the shape of the square cut out.

The next day I glued the top fabric on rinse and repeat like the lower side. After all was dry I ironed it down to 250 deg F then 300 and finally 350 (both sides). I marked out all the rib stitches making sure to avoid the control tubes and then pre-punched them (both sides). Next I installed the rib reinforcing tape on both sides. I had just enough time to rib stitch one of the aileron bay ribs. Did I also mention I have been battling a head cold all week I’m pretty wiped so I will probably head to bed.

Time spent 12 hours
Total time spent 1014 hours

Lower wing sanding and final assembly, making a carbon fiber turtle deck

Sorry for 2 week no post but i have been working on things. I have been sanding the clear coat on the lower wings with 320 open coat to smooth them out and to provide some grip for the glue. I then final installed the the lower wing control rods. Because small amount of clearance between the 90 deg bell crank control rod bearing bolt and the drag wire I had to install one of the control rod bearing bolts upside down for proper clearance of 1/4″ I used a castellated nut and cotter pin which proved to be a pain the ass to install under the I-strut wooden sheet panels.

I have been toying with building a carbon fiber turtle deck for awhile so I decided I was going to do that. I thought for awhile I could build it out of 1 layer of 282 (5.6 oz graphite) and 1 layer of 5.6 oz fiberglass but it came out too flimsy so I added yet another later of 282 and 5.6 oz fiberglass. Unfortunately it doubled the weight and now the skin weighs 3.25 lb which is the same as 0.025 2024T3. I probably could have saved some weight by using less layers and instead 2 total layers and some nomex however that stuff is expensive. The second layer really helped stiffen the skin up
Anyway I used this simple aluminum form made from particle board and 0.025 2024T3. I sprayed several layers of really cheep aerosol hair spray like Aqua Net super extra hold to keep the epoxy from sticking to the aluminum. As it turns out the higher the hold the better the anti-stick quality of the hairspray for molds.

Time spent 20 hours
Total time spent 1002 hours

Elevators and horizontal stabilizers rib and finishing tapes

Roll up post for the last two days. After I got the rib stitching completed I started in on the rib tapes and finishing tapes. I cut and started all the one side of tapes after I was done I finished the gluing the rest of the tapes. I flipped the surfaces over and rinse and repeat. Now on the finishing tapes, which are a little more complicated, I worked for several hours getting them to curve around the radius. I had a little order issue the the trim tab cutout it will be fine, but maybe not quite as clean as I hoped. besides this isn’t a show plane its a go plane. Anyway here are the photos for the day. So the stabilizers and elevators are covered and ready for final ironing and then some brush coats of the Eko-Fill.

Time spent 10 hours
Total time spent 982 hours

Final Clear coat on the lower wings, Rib stitching the horizontal tail and elevators, eko fill on the upper wing

Yet another roll up post, I have been bad at not updating daily what I have been doing sorry! I was able to get the second brush coat on the upper side of the upper wing on the 7 dec after that I did the second coat of clear coat on the bottom side of the lower wings. The next day I was able to flip the lower wings over and get the clear done on that side too (8 dec). Last night (9 dec) was able to complete the rib stitching on one of the horizontal stabilizers and the elevators.

Time spent 10 hours.
Total time spent 972 hours

Breather tube and coating the upper wing with Eko-Fill

I finished off the breather tube install just to realized I will probably take it back out to make covering the bottom of the fuselage easier, oh well. Anyway here is the photo.

The last two days I have been working on the upper wing eko-fill. I started by ironing the tapes to make sure they were down. I then masked off everything I didn’t want painted. I then vacuumed the wings to get the big particles off, followed by the eko-clean and rinsing as showing the stewart’s manual. I then brushed the first coat and the next day I finished the bottom side of the top wing with the second brush coat so 1 cross coat. I have decided that I will never use terry towels again because they shead little balls of cotton on the taps and that gets into the eko fill and I you have to sand it off later, not hard to do but annoying. So I switched to jersey towels and they don’t shed and work just as good. So anyway I finished cleaning the upper side of the upper wing and brushed the eko-fill first coat on the wing to let dry overnight.

Time spent 10 hours
Total time spent 962 hours

Fuselage sheet metal

A roll up of several days work I measured and cut and folded the left and right fuselage side panels. Since the side panels were installed already and had the nut plates in place. I used my hole transfer tools to drill new holes. The right side panel came out better than the left but with some careful coursing I was able to make the panel work. I may still redo the left panel but only time will tell. The bottom panel needed to be drilled for screw holes along with new holes for the new panel brackets. Also I spent quite a bit of time notching the panel to clear the spar brackets.

I tried the Kimball sheet metal screw trick and it worked, but I saw it starting to break down in the near future and the screws stripping so I decided to install #8 nut plates.

With some feedback from Stuart on post covering of this fuselage with the set back angles on the stringer it noted that the stringers looked like two bumps because the covering sagged between. I thought I would fix that by adding a piece of sheet metal bridged between the two stringers. This is two fold because I also need to make sure that my torque tube doesn’t touch the fabric either if the fabric sags between by more than 1/4 to 1/2 inch I will be contacting. So the sheet metal just made sense. I made mine out of 0.032 6061T6 and screwed it to the stringers.

Time spent 8 hours
Total time spent 952 hours

Finishing the tapes on the upper wing, Making rudder cable fairleads, Taping the ribs of the left horiz stab

Yesterday I got in an order from Aircraft Spruce which had a 1 ft stick of 3/4″ delrin plastic and 6″ Ceconite 102 light for the the aileron coves. I also got some other stuff but they are unimportant to this post. The reason I needed the delrin plastic is that I 4 of my rudder cable fair leads are 3/4″ 0.049 tub rather than the standard 7/8″ 0.049 tube. Well I couldn’t find a parts supplier that has the fair lead so I decided to make my own for the 4 that I needed. I used my drill press and angle grinder similar technique as a lathe and turned out 4 new fair leads. After the fair leads were fabricated I started working on the large tip tapes on the upper wing. I cut out another tip tape for the right side of the upper wing. I went ahead and installed the two tapes and glued them down. They tape alot of heat to get them to conform to the shape but they do. I then cut out a finishing tape for the aileron coves and glued them in. While things were drying I marked out and started tapes for the left horizontal stabilizer.

Time spent today 5 hours
Total time spent 944

Finishing the Elevator trim tab and covering the right elevator

Today I got right to work finishing the elevator trim tab which I folded last night. I got everything situated (piano hinge and tab) then I drilled 9 holes and use some cherry blind rivets to secure everything I checked the fit and everything was good so I started in on covering the elevator. I got the elevator completely covered by the nights end.

Time spent today 4.5 hours
Total time spent 939 hours