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I've been focusing on large lightweight rockets and my RC rocket glider kits I sell and haven't felt motivated to build anything model related for quite a while, I finally got the bug again...
I have a nice estes Master series Mercury Atlas kit that I have flown a bunch, I modified it to have permanently mounted clear fins which I like a lot better than the duck feet. won an opened but complete kit last summer at FITS(Fire in the sky) and wanted to do another but in a style similar to the Atlas 4B test flight with flattened heat sink re-entry warhead style. I had done this same model in a 10" version using a foam structure that weighs 6 pounds rtf. The front end is not exactly right but I wanted something that I could do easily without buying/making a lot of parts. I think the side tunnels on the 4B were both long, but I haven't found any drawings showing it, and I'll just ignore that part.
Kit assembly was as per the kit except I added a 1/8" kevlar strap mounted to the motor mount running forward to attach a 3/8" elastic to to. The elastic will go over the lip of the tube and help prevent zippers.
For the cone I cut it where the transition bells out to mate with the mercury capsule, flipped it over, and sliced it to reduce the wide diameter to match the transition, then glued it with an added tab. I added a styrene strip in the lower transition to help center it when gluing made from scrap from the kit vacu formed parts. For the warhead, I simply used the normally discarded piece at the front of the blow molded transition section sanded down to fit and glued it in place.
The fins are 1/32" polycarbonate slotted through to the inner tubes and glued in place. the 1/32 is very flexy and I designed the fins with no notches or sharp corners to prevent breakage. It's very easy to work with, just score, bend and it breaks clean. I've got it partially masked for painting, then starting the silver mylar wraps. I also added rail buttons with small standoffs instead of the usual launch lugs. This will fly in E-30-4 Aerotech motors.
I'll need to add some nose weight as the CP shifts forward.
I'll attach the very simple rocksim I made, this is not for CG or flight sims, just for shape to show me the CP locations before and after and to figure out where it will need to balance, ignore the weights or CG location shown.
My foam version that is 10" diameter...
I have a nice estes Master series Mercury Atlas kit that I have flown a bunch, I modified it to have permanently mounted clear fins which I like a lot better than the duck feet. won an opened but complete kit last summer at FITS(Fire in the sky) and wanted to do another but in a style similar to the Atlas 4B test flight with flattened heat sink re-entry warhead style. I had done this same model in a 10" version using a foam structure that weighs 6 pounds rtf. The front end is not exactly right but I wanted something that I could do easily without buying/making a lot of parts. I think the side tunnels on the 4B were both long, but I haven't found any drawings showing it, and I'll just ignore that part.
Kit assembly was as per the kit except I added a 1/8" kevlar strap mounted to the motor mount running forward to attach a 3/8" elastic to to. The elastic will go over the lip of the tube and help prevent zippers.
For the cone I cut it where the transition bells out to mate with the mercury capsule, flipped it over, and sliced it to reduce the wide diameter to match the transition, then glued it with an added tab. I added a styrene strip in the lower transition to help center it when gluing made from scrap from the kit vacu formed parts. For the warhead, I simply used the normally discarded piece at the front of the blow molded transition section sanded down to fit and glued it in place.
The fins are 1/32" polycarbonate slotted through to the inner tubes and glued in place. the 1/32 is very flexy and I designed the fins with no notches or sharp corners to prevent breakage. It's very easy to work with, just score, bend and it breaks clean. I've got it partially masked for painting, then starting the silver mylar wraps. I also added rail buttons with small standoffs instead of the usual launch lugs. This will fly in E-30-4 Aerotech motors.
I'll need to add some nose weight as the CP shifts forward.
I'll attach the very simple rocksim I made, this is not for CG or flight sims, just for shape to show me the CP locations before and after and to figure out where it will need to balance, ignore the weights or CG location shown.
My foam version that is 10" diameter...
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By using slots through the tubes it helps to support the fins and puts less strain on the glue joints. I've found normal CA will tend to weaken the polycarbonate and they can crack with a very very hard flexy hit, I have not found that with the insta flex...
