Fabric and Finishing

Fabric and Finishing

• The P1 was covered with PolyFiber materials and supplies, which were easy to work with and produced nice results.

  All planes get covered up to the tapes in the same manner (fabric weight depending on airplane size and speed). For certified airplanes, the only acceptable fabric schedule is 3 cross-coats of PolyBrush (a weave-filler and all-over adhesive), 3 cross-coats of PolySpray (to completely block UV, which breaks down polyester fabric), and then 3 cross-coats of PolyTone. There's enough material thickness there that defects can be filled and sanded out, and the finished product will be show-quality.

  The STC manual suggests covering an ultralight with only Polytone, but with a UV blocker added that provides minimal protection. It'll look rougher, and the fabric life outdoors would be only a few months.

  I split the difference and did a beefed-up version of the ultralight system. After tapes, a single cross-coat of a 75%PolySpray/25%PolyBrush was sprayed on. The uniform silver color highlights all the defects that didn't get ironed out earlier, and there's enough thickness to allow sanding of most small defects without hitting fabric. Then another spray over the tapes (where the silver was usually sanded off). The final finish was done with PolyTone with UV blocker added: one coat that was sanded, and a final finish cross-coat that hid the silver and gave a uniform finish.

  

  The results are very pretty, very light (I'd estimate less than 1/2 the weight of regular 2.7oz dozen-coat covering), and should give the airplane some protection from the sun. This is my own homebrew mix - copy at your own risk.

• The first fabric attempt wasn't pretty (I took a mulligan and stripped it), but a perfectly-timed fabric class at OSH '09 refreshed all the skills from the glider restoration and the weekend classes at Aircraft Spruce.

  

  

  The elevator was covered and painted in the re-constructed paint booth from the pod painting.

  

  The shortened horizontal stabilizers were covered and painted around the same time as the elevator. BCS games provided motivation/entertainment.

  

  The ailerons were covered in mid-Feb 2010. A temporary paint booth was built between the wings.

  

  The wings were covered in May and June of 2010. The first spray coats were done in a quick-and-dirty booth made by stretching a tarp between the trailing edges. For final coats a full booth was built, extending the booth used for the pod.