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The next step after window installation, as documented in the Builder's Manual, is to create the doors. Seems logical to me. The doors are created by cutting them out of the existing fuselage structure which saves the time and effort of having to build them from scratch, and insures a perfect fit. Once removed, the doors are strengthened, as is the fuselage around the door cutout, and latching hardware is installed. Before any of this can happen, however, the manual very clearly states that the hinges should be rigged into place, and the door stops should be fabricated. Door Stops
I did this in 4 separate sessions, upper
and lower stop for each door, because working above the window Door Hinge Dilemma Now comes the frustrating part. When I first received my fuselage sub-kit from Glassic Composites, they backordered all my door hardware, including the hinges. Then they went bankrupt, but you already knew that. I contacted KLS Composites and inquired about getting this badly needed hardware. They said that their machine shop people were pretty busy working on the landing gear, so it would be a while. Not the answer I was hoping for, but at least it was honest. The hinge arrangement on the factory demonstrator SQ2000 was really nothing to brag about--some might even say it was a bit on the cheesy side--so I thought I'd try to come up with a new design.
A few weeks later, when I was strolling around the parts tents at the Arlington Air Show, I happened across a bin of surplus gooseneck hinges. I bought 4 of them. Grand total: $2.00. Pretty nifty. Now to build a test section to see
if these hinges would actually work. I used the scrap piece that was cut out of the bottom of the fuselage as my test article.
The curvature wasn't exactly right, but it was a valid By now I was getting a bit frustrated. Although cheesy, I thought maybe I would forget trying to reinvent the wheel and just use the factory hardware... if I could get it, that is. A few gentle reminders (and a couple of months) later, I received a box of door hardware at my front door. Kudos to KLS Composites for sending this stuff to me at no charge, which they were under no obligation to do. The box contained center cams, push rods, locking pins, guide sleeves, but no hinges! Another email to the factory saying, basically, "wazzzuppppp?" My reply was that they didn't send hinges because another builder had come up with a better way to hinge the doors by adapting Velocity hardware. That was good info to get, and I called my fellow builder who was quite helpful, but why didn't they tell me that 2 months ago? Sheesh. So I contacted Hiroo, a Velocity SUV builder, who sent me some shots of his hinge installation. I also got in touch with a fellow SQ2000 builder, Norman Caruana, who was very helpful and sent me some photos and drawings of his installation. He also gave me Velocity's part number for the hinges, so I placed a call the Florida and ordered 4. They cost around $50, if I recall correctly. Turns out their hinges are just MS20001 piano hinge extrusion, which is available from Wicks, cut into 2" widths. Moving Forward
Once the plies had cured, I roughly faired the edges with SuperFil, then marked the new cut line. There was no template for this... I just took a few measurements and drew what looked reasonable. Transferring the design to a piece of mylar allowed me to flip it over for use on the other side. Now there was nothing left to do but break out the saw and start cutting. Nothing too tricky about that; just had to keep a steady hand so that the cut lines would be smooth.
After cure, the door stops were trimmed and sanded so that they projected about .15" into the door opening. The next step was to build the door seal backstop. The backstop is 2 plies of S2 glass layed up over a temporary foam spacer to provide a fixed (3/8") distance from the door stops. After the cure, the foam was removed by means of plastic scrapers and a Dremel tool then trimmed to project ½" beyond the door stop. This "backstop" now serves as a mounting platform for the door seal, which clips in places and will provide a tight seal (hopefully) when the doors are closed. There is mention in the Builders' Manual of an inflatable door seal option, but I don't know of any SQ2000 builders who actually have such a thing. Hinge Installation The nice thing about the
KLS Composites hinge design was that it used spherical bearings at the On the fuselage side, I
began by removing the foam core where the
hinges would reside. By The door side of the hinges were tapped with 10-32 thread, so each door can be easily removed from the airplane by removing 8 screws. With that complete, I finished the layups on the inside of the fuselage around the hinges to close out the area and provide a constant sealing surface. The photo at right is shown before the peel ply and surplus foam core was removed (fuselage upside-down in the photo). Door
Reinforcement Now that the hinges were basically complete, the next step was to strengthen the doors. This was accomplished by fabricating and bonding a ¾ inch thick by 2 inch wide "frame" of foam core around the door, then glassing over it with S2 glass. It was a fairly straight forward process, but care had to be taken to avoid messing up the windows. This photo shows the foam bonded in place, shaped and smoothed before the fiberglass was installed over it.
Tweak Now for the crappy part. When I originally cut out the R/H door, I noticed that it "stress relieved" itself a little bit. By that I mean that the contour changed slightly. The L/H door did not do this and went back into the cutout perfectly. I didn't worry too much about it, figuring that between the hinge attach points and the latching mechanism it would be forced into conformity. Well, that was a bad decision. I should have corrected the problem before doing the door reinforcement because now I had stiffened the door into the improper contour. I attempted to re-contour the door by bending it with clamps, dead weight, and straps while heating it to 175° F. I had marginal success getting it back into shape, but the fit was still unacceptable.
There were some other areas around the door that were just a bit beyond flush, but a little SuperFil on the fuselage took care of that. I also found that the gaps around both doors where pretty good, but could be better. Strategic applications of epoxy/flox, epoxy/micro, and/or SuperFil combined with duct tape and mold release remedied this. Oh yeah, and sanding. Was I spending too much time on this? Would anybody even notice the gaps around the doors? Weeks were turning into months. Yeah, it's got to be right. I don't like doing things "half assed." After reading Paul Lee's web page, I see that he had a similar problem with his door(s), but he was smart enough to correct it before adding the stiffeners. Hardware Getting near the end of this long chapter now. All I had left to do at this point was to install the handles and latching hardware. I opted not to use the KLS Composites door handles since they projected into the air stream about 2 inches. Instead I bought 2 door handle assemblies from Lancair. Pretty slick design with (nearly) flush handles. A bit pricey at $300 for the pair, but what the heck. There wasn't much modification required to adapt the Lancair parts since the locking action was similar to KLS's system. I used KLS's locking pins
despite the fact that they're over-designed by a large margin: 7/16"
diameter steel pins, 4 The last piece
of the puzzle was to install the gas struts. The struts hold the
doors in the open position, and due That about wraps up the door chapter. Certainly that was the most challenging task to date. According to my construction log, I invested 318 hours in the doors. No wonder it's taking me so long to build this airplane.
Final Touches
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