Posts: 1598
Joined: 9/1/2002 From: West Chester, OH, USA Status: online
Main gear doors (cont).
pic 1: Got the other (left) door working. The door was stopping about 70% open and the wheel was catching the corner of the door. I checked and sanded all the FG that may be touching the piano hinge pin: no luck. I put some pieces of ply on the door where the spring contacted the door for more force: no luck. I bent the part of the spring that rests on the fairing by putting a 90 degree bend in the wire for more force: luck. (just like putting engines in our planes: too much power is almost enough!).
pic 2/3: closed/open positions. This door opens farther than the other side: about a 1/2" more. Even though I did both sides, the suttle geometry of the strut, fairing placement, door curvature, etc makes them a little different. I won't have to worry about this fishing line breaking: I couldn't cut it with scissors and had to use a razor blade! Now we've got to fill in that hole on the fairing with a small door.
< Message edited by samparfitt -- 1/19/2007 5:01:56 AM >
Posts: 1598
Joined: 9/1/2002 From: West Chester, OH, USA Status: online
Belly pan.
pic 1: The bottom of the pan had a couple of 'bulge' spots on each side about 3" back from the front (along that ridge), that needed sanding down so the pan would lay flush on the wing.
pic 2: Masked off the area to keep 'slop' to a minimum. I'll be using the glassing resin used on glassing the wings to hold the pan down. I used it on the center section of the wing for re-inforcement with heavy duty FG. I've been told that glassing resin is just thinned out epoxy but this ZAP resin seems extremely hard and strong.
pic 3: I first pushed the front of the pan on and put screws into the front of the pan to insure the front was flush. I had to do this first before pushing down on the rest of the pan to the wing because the front was sticking out about an 1/8" past the LE and it looked pretty ugly. After the front was taped and screwed, I pushed down the rest of the pan and screwed it down to keep the pan edges flush with the wing. After the resin dries, I'll remove the screws and glass and smooth that area to blend into the wing. No use making the pan removable since there's nothing important to access under the pan. mmmm, I just noticed in the picture that I missed putting in a temporary screw on the back left side...better go do that!
< Message edited by samparfitt -- 1/19/2007 3:33:11 PM >
Posts: 1598
Joined: 9/1/2002 From: West Chester, OH, USA Status: online
belly pan (cont)
pic 1: Some tape on both sides of the work area to reduce unwanted sanding and keep the new materials being added to a confined space. I used a sheet of 120 grit paper folded over twice and just put my finger in the center to round over the edge of the belly pan where it meets the wing's surface. Some Bondo glazing putty (part 907) from my local auto store and a squeegee cut to about a 1/2" to apply the bondo to smooth out that transition from the belly pan to the wing.
Gear doors (cont) pic 2: That CA didn't seem to want to hold onto that fishing line so I got some more good use of those #0X3/16" screws. The screw fits perfectly in that 1/16" hole in the gusset at the left side of the fairing, and the screw is better anyhow since I can now easily adjust the fishing line length, if needed.
< Message edited by samparfitt -- 1/19/2007 6:16:38 PM >
Posts: 1598
Joined: 9/1/2002 From: West Chester, OH, USA Status: online
Belly Pan (cont)
pic 1: While the masking tape was still on the wing and belly pan, I wet sanded with 220 grit the glazing putting down to the masking tape. After removing the masking tape, I did the final wet sanding to make the glazing putty flush with the wing surface and belly pan. I had planned, but forgot, to glass the inside of the belly pan with heavy duty FG before attaching it to the wing. I was going to glass and put the belly pan on the wing at the same time since the belly pan is 'bent' a small amount to get it to be flush with the wing surface. I figured this would help keep the belly pan from cracking if I had to do a 'retract up' landing.
pic 2: I put some .5 oz FG along the belly pan edge to insure the glazing putty doesn't crack from all that engine vibration and wing stressing. I understand SIG no longer carries .5 oz FG but Hanger-9 does.
Machine gun access covers. pic 3: I sanded the bottom edges to give some 'tooth' for the epoxy to grab onto the edge of the covers. I also sanded the top edge of the lip so it would 'angle down' and be flush to the wing . Some box tape to hold them down and in place while the epoxy is drying. I moved the gun access over from where the drawings showed them. They were partially behind the servo covers but I wanted to make sure the rods connecting the servos to the flaps didn't hit the covers.
< Message edited by samparfitt -- 1/20/2007 6:17:45 PM >
Posts: 1598
Joined: 9/1/2002 From: West Chester, OH, USA Status: online
wing (cont) pic 1/2: To strengthen the wing center I glassed the center section with heavy duty FG. I left a 4" open area in the back to insure the wing seats properly with the fuse: the fuse has about a 3 1/5" lip on the back where the wing bolt attaches.
Stab and elevator (cont)
pic 3: I drilled holes for the four large hinges on each side of the elevator. Since the hinge pin is at the center of the LE radius, rectangular holes were cut for movement of the elevator.
pic 4: Elevator temporarily attached to the stab. The kit also has light balsa hinge support blocks that I CA'ed on each side of the elevator where the hinges are attached.
pic 5: This should be plenty of elevator movement.
pic 6: The kit has one metal elevator control horn plus two dowels. I put some masking tape on the end of the holes so no epoxy goes in them for our first 'glue up'.
pic 7: The dowels are epoxied into the elevators using the metal control horn as a guide for width and a couple of 'weights' on each elevator to keep them flat and level with each other.
pic 8: A 1/4" thick ply in the kit is notched for the metal control horn movement and then epoxied to the center of the stab.
pic 9: Forgot to mention that the LE edge of the elevator has to be 'grooved' out where the metal control horn runs parallel to it. I used an Xacto knife to cut a 'V' and then rounded it out with the top grinding bit in the picture. The bit is cylindrical shaped. I used the lower grinding bit to finish hollowing out the LE of the elevator where each hinge pin is located. This bit is ball shaped.
< Message edited by samparfitt -- 1/22/2007 7:31:09 PM >
Posts: 1598
Joined: 9/1/2002 From: West Chester, OH, USA Status: online
stab and elevator (cont)
pic 1: Stab and elevator temporarily connected with four large hinges on each side and metal control horn connecting the two elevators.
pic 2: Dubro's 4/40 steel threaded rod ends (part # 302) is connected to the top hole in the control horn. I used the top hole to give the movement a more 'gentle' and 'finer' movement. One side of the spit end is threaded so a provided screw threads through from the other side and a provided nut is then put on the end to keep the screw from coming loose (I also put locktite on it). The other end is threaded to easily connect/disconnect a 4/40 rod later on when we connect up the servos.
pic 3: Dubro's 5/32" nylon landing gear straps (part # 239) was used to hold the control horn to the stab. A 1/64" ply was needed as a shim to keep the control horn moving 'freely'.
pic 4: That 1/4" ply epoxied on the stab is needed to move the control horn out to the same radius that the hinge pins are located. This means a fairly deep groove is needed on the LE of the elevator that the LE of the control horn rests. All the hinge pins and LE of the control horn must be aligned to prevent any binding.
pic 5/6: Up/down elevator movement.
< Message edited by samparfitt -- 1/23/2007 12:30:25 AM >
pic 1: I'm looking for a 'cost effective' sliding canopy. I took some 3/16" square brass channel and a 45 degree 'groove' carbide routing bit, put a feather board on the router table to hold the square brass against the router fence and came up with this. I had the groove bit up just enough to cut a slot down one side of the square brass channel. I then put the ball end of a dubro 1/16" threaded ball link into the slot. It seems to work OK. I figure the other threaded end of the ball link can be screwed into the canopy. Any ideas or thoughts would be appreciated! The channel basically looks like this: [_]. The ball (pic 2, second from the right) then can slide in the middle.
< Message edited by samparfitt -- 1/23/2007 1:30:34 AM >
I did this on my sportman p40 after seeing a guy on warbirds site use this method on his Pica 1/5 P40 . He cut the ball link down a bit , glued a small ply rail onto the inside of the canopy then screded two balls links into each side at the appropriate height into the ply rail . You have to be careful that you dont get the canopy offsetting to far off the fuse vs so that it does not match when closed the front part of the canopy . I think his post is still active on warbirds.com , his was actuated by a small ait cylynder , mine was simply done by hand
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RE: Yellow P-40 build thread - 
