Well, four days after having a main gear tire go down during landing (and grinding off about an inch of wheel pant), the -8 is fully flight-ready once again. As a matter of fact, I took it around the pattern just before sunset! It didn?t really take that much total time to do the work ? it?s just the waiting time for fiberglass to cure that took most of the week. Here are a few things I learned along the way (Remember, I built a metal airplane because I consider myself a novice at glass-work. Some of this will be glaringly obvious to those folks who?ve built plastic airplanes?)
1) The best place to find tires and tubes in my experience is Desser ? call ?em up, tell ?em what you need, and two days later, UPS drops them at your door ? no shipping charges above the price of the merchandise! I went with the Michelin tubes that everyone recommends.
2) Yeah, I know it?s not my native north-country, but it?s winter in Texas too (that means it is below 60 degrees at night?), so cure times out at the hangar with West Systems ?fast? catalyst are about six hours. That actually works out OK ? get up with the cows, drive to the airport, prep and glass for about a half hour, then go to work. After work, back to the airport for another layer or task. If you?re lucky, you can get another coat in about the time of the late news?that?s how I get it done quick!
3) There is still no substitute for power tools. I use a sanding disk on an angle-die grinder for major surgery, and an Orbital Sander with 120 grit for surface shaping. Final smoothing with 220 on a Mouse sander. I figure I?ll let the paint shop do the finish sanding before they paint.
4) The bottom curve of the wheel pant (mine was ground down about an inch) can be reshaped by taking a piece of peel-ply and taping it under the pant with a slight sag. This forms a female mold that you can lay glass inside (assuming the pant is right side up, and of course, you have the front half off). Lay your impregnated glass inside on the peel-ply, and overlap a sufficient amount to give structural integrity. When dry, turn it over, rip off the peel-ply, and add dry micro (I like peanut-butter consistency) to take it out to the mold line. When that is cured, use the Orbital sander to get the final shape. Once you like the shape, add a final layer of resin to make a hard finish, and sand that with the finish sander to give a nice, pinhole-free surface.
5) If, like me, you ground away the edges of the wheel opening in the pant, use the same technique as above with the peel-ply as a mold on the outside. Make it longer than necessary, and trim it when re-mounting.
6) Wheel clearances were discussed the other day in a thread, and all I can tell you for sure is mine weren?t big enough! Mine were about the width of a little finger. They are now about a thumb! I sure as heck don?t want to have THIS happen again!
7) I heard the pump on my West Systems gallon can of resin suck air as I mixed the last batch of epoxy ? I started that can at the start of the airplane project, so a gallon will build an -8, and do some repairs afterwards?.
8) Fitting the pant and checking the clearances is a lot quicker and easier if you use clecos instead of screws to temporarily mount it to check the fit (duh!! Like I shouldn?t have known that?). Silver clecos work perfect in #6 nut plates.
9) I figured out one thing I forgot the first time that might have been a strong contributor to my tire failure, since what I found was a razor-like slit in the sidewall. When I finished the wheel openings the first time, I neglected to smooth the edges of the openings when they were done?you know, when you get close to flying, you get fixated on the end! Take the time (once you have the clearance you want), to take them off and sand the edges just the way you would a piece of aluminum. No, it?s not to prevent cracks, it is to make an edge much less likely to slit the tire if you DO get contact! Mine are now nice and round.
OK, so much for confession, and with all this epoxy dust in what is left of my hair, I feel I have done enough penance?.
May you not have to need any of this information!
Paul
1) The best place to find tires and tubes in my experience is Desser ? call ?em up, tell ?em what you need, and two days later, UPS drops them at your door ? no shipping charges above the price of the merchandise! I went with the Michelin tubes that everyone recommends.
2) Yeah, I know it?s not my native north-country, but it?s winter in Texas too (that means it is below 60 degrees at night?), so cure times out at the hangar with West Systems ?fast? catalyst are about six hours. That actually works out OK ? get up with the cows, drive to the airport, prep and glass for about a half hour, then go to work. After work, back to the airport for another layer or task. If you?re lucky, you can get another coat in about the time of the late news?that?s how I get it done quick!
3) There is still no substitute for power tools. I use a sanding disk on an angle-die grinder for major surgery, and an Orbital Sander with 120 grit for surface shaping. Final smoothing with 220 on a Mouse sander. I figure I?ll let the paint shop do the finish sanding before they paint.
4) The bottom curve of the wheel pant (mine was ground down about an inch) can be reshaped by taking a piece of peel-ply and taping it under the pant with a slight sag. This forms a female mold that you can lay glass inside (assuming the pant is right side up, and of course, you have the front half off). Lay your impregnated glass inside on the peel-ply, and overlap a sufficient amount to give structural integrity. When dry, turn it over, rip off the peel-ply, and add dry micro (I like peanut-butter consistency) to take it out to the mold line. When that is cured, use the Orbital sander to get the final shape. Once you like the shape, add a final layer of resin to make a hard finish, and sand that with the finish sander to give a nice, pinhole-free surface.
5) If, like me, you ground away the edges of the wheel opening in the pant, use the same technique as above with the peel-ply as a mold on the outside. Make it longer than necessary, and trim it when re-mounting.
6) Wheel clearances were discussed the other day in a thread, and all I can tell you for sure is mine weren?t big enough! Mine were about the width of a little finger. They are now about a thumb! I sure as heck don?t want to have THIS happen again!
7) I heard the pump on my West Systems gallon can of resin suck air as I mixed the last batch of epoxy ? I started that can at the start of the airplane project, so a gallon will build an -8, and do some repairs afterwards?.
8) Fitting the pant and checking the clearances is a lot quicker and easier if you use clecos instead of screws to temporarily mount it to check the fit (duh!! Like I shouldn?t have known that?). Silver clecos work perfect in #6 nut plates.
9) I figured out one thing I forgot the first time that might have been a strong contributor to my tire failure, since what I found was a razor-like slit in the sidewall. When I finished the wheel openings the first time, I neglected to smooth the edges of the openings when they were done?you know, when you get close to flying, you get fixated on the end! Take the time (once you have the clearance you want), to take them off and sand the edges just the way you would a piece of aluminum. No, it?s not to prevent cracks, it is to make an edge much less likely to slit the tire if you DO get contact! Mine are now nice and round.
OK, so much for confession, and with all this epoxy dust in what is left of my hair, I feel I have done enough penance?.
May you not have to need any of this information!
Paul
