I've been working on a way to lighten up the load of bombs/drop tanks on my Flightline 1600mm P-51D Hurry Home Honey. The PLA bombs I printed and have successfully flown and dropped on flights were good and realistic, but the hard desert floor we have here in NW Wyoming is very hard on things that go bump in the night. Sometimes they come back without a scratch, sometimes damaged on impact but usually repairable, and sometimes they just go missing and not found again.
Elbee clued me in to a filament called TPU, a type of Polyurethane mix that is very flexible and more resistant to damage when they hit the hard ground., in theory. I have had some problems working with some of the larger parts I have printed in TPU, but did manage to make two simulated 500# bombs and have tested the finished prototypes on the bench for drop testing this afternoon. TPU hopefully will be very impact resistant, but it is not as well and cleanly printed as are other filaments like PLA. But then, these bombs are strictly for demonstrating successful dropping from a model airplane at altitude, and not for up close inspection. The others I have already printed and flown in some cases are the ones to show for static viewing.
If weather is good tomorrow morning, I'm going to try at least one drop test with them, possibly two and see how they survive, if they DO survive. Should be an interesting test. If this goes well, I'll print up the larger scale 110 gallon drop tanks that have flown printed in the heavier and more fragile and stiff PLA material.
Below are a couple pics of my work in the past couple of days. One pic shows the under-development TPU bombs (silver) with two earlier PLA bombs. The other photo shows the TPU bombs painted as I will fly them tomorrow. I had to open a slit in the bombs so that they could slide into the stock Flightline wing pylon. The material of the bomb is so thin that it is very pliable but fits well onto the pylon and does well in drop tests on the bench today. They are substantially lighter than the PLA bombs, weighing under 2 ounces each.
Cheers
Davegee
Elbee clued me in to a filament called TPU, a type of Polyurethane mix that is very flexible and more resistant to damage when they hit the hard ground., in theory. I have had some problems working with some of the larger parts I have printed in TPU, but did manage to make two simulated 500# bombs and have tested the finished prototypes on the bench for drop testing this afternoon. TPU hopefully will be very impact resistant, but it is not as well and cleanly printed as are other filaments like PLA. But then, these bombs are strictly for demonstrating successful dropping from a model airplane at altitude, and not for up close inspection. The others I have already printed and flown in some cases are the ones to show for static viewing.
If weather is good tomorrow morning, I'm going to try at least one drop test with them, possibly two and see how they survive, if they DO survive. Should be an interesting test. If this goes well, I'll print up the larger scale 110 gallon drop tanks that have flown printed in the heavier and more fragile and stiff PLA material.
Below are a couple pics of my work in the past couple of days. One pic shows the under-development TPU bombs (silver) with two earlier PLA bombs. The other photo shows the TPU bombs painted as I will fly them tomorrow. I had to open a slit in the bombs so that they could slide into the stock Flightline wing pylon. The material of the bomb is so thin that it is very pliable but fits well onto the pylon and does well in drop tests on the bench today. They are substantially lighter than the PLA bombs, weighing under 2 ounces each.
Cheers
Davegee
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