#1
|
|||
|
|||
A model rocket model, K-7 Phantom scratch build
Sure, the Phantom isn't really a rocket. Heck, it has no fins. But, it is in the 1963 catalog and has a K-number designation, so it goes on my list to build the original kits starting from the beginning.
It all starts with a plastic tube. It probably was mylar back then, but as I mentioned on an earlier build, I found some plastic tubes at a Walgreens that were within a few thousandths of an inch with the correct radius. Of course, I also needed a model of the engine. According to the picture in the instructions - which I got from JimZ's site, as one could have expected, the model rocket engine model was filled like a C engine. But, I had just been launching with my class, and we used A engines. So, I sliced a used A engine case lengthwise, being careful to leave the engine rating exposed. I decided to build it to represent how an A engine is packed. Luckily, the clay nozzle was almost perfect when I split it, so it was good. I then used a launch rod to plug the nozzle, and a 1/2" dowel with some tape around it to plug both ends of the half engine casing. Once I poured in some polyurethane resin, I had a model rocket engine model. Before it set up really hard, I shaved of the top surface with my knife. Then, with some tape, acrylic paint, and a detail brush, I made a mock model engine. edit: Emphasizing that I didn't split a live engine lengthwise. It would go against everything that I tell my class about safety. And, everything that I hold dear about not burning off my fingers. Last edited by DavidQ : 06-22-2016 at 12:17 AM. |
#2
|
|||
|
|||
Once I finished the engine and tacked it into place, that was most of the work.
Except I needed an engine block. A green one to match the kits of the day, I think. And, I didn't have one and didn't want to order one. So, using an engine casing trimmed to 3/4" long, and some mint green acrylic paint, I made one. I used a 24mm green engine block that I did have as a color guide. Then, packing some recovery wadding, a parachute, a nose cone, elastic, etc. the model rocket model was done. It's sitting on my shelf next to my other K-7 Phantom, the later model which I built from a kit - it has fins and looks like an Alpha. It likely will appear in a later build. You can hardly tell them apart! (Oops! This picture from the catalog has a tube-colored engine block. Later pictures on the hang tag had the darker one, which I must have assumed to be the green one. Oh well. If this were government work, it would be good enough.) Last edited by DavidQ : 06-22-2016 at 12:39 AM. |
#3
|
|||
|
|||
Nice project!
Guess: That oversized engine block was one of the old-style balsa thrust rings. Hole drilled through the center. I made a few for my own "early days of Estes" projects. BT-30 balsa bulkheads that I hand drilled.
__________________
NAR #27085 - Oregon Rocketry - SAM |
#4
|
||||
|
||||
I saw an original Estes cutaway engine on Ebay a while back:
http://modelrocketbuilding.blogspot...mmy-engine.html Your engine looks better than what Estes produced. The Estes cutaway engine looks like it was cut in half with a bandsaw! Great work on your "K" kit builds!
__________________
Hans "Chris" Michielssen Old/New NAR # 19086 SR www.oddlrockets.com www.modelrocketbuilding.blogspot.com http://www.nar.org/educational-reso...ing-techniques/ Your results may vary "Nose cones roll, be careful with that." Every spaceman needs a ray gun. Look out - I'm the Meister Shyster! |
#5
|
|||
|
|||
Quote:
Good call! I missed that. The Phantom instructions clearly call it a "Balsa Engine Block # EB-20". The 1963 catalog even calls an EB-20 a BT-20 engine block, 3/4" long, made of balsa. That also explains why the engine block looks almost like recovery wadding in the B&W photo. My ignorance about the older engine blocks led me to totally miss that detail. Thanks! But, I'm not changing it. I really wanted the green engine block. |
Thread Tools | Search this Thread |
Display Modes | |
|
|