Friday, December 31, 2010
Review: Mini V-2
My Mini-V2 (2nd from left) is a semi-scale model based on BT-50 tubing. I was motivated to build this V2 after seeing plans for a BT-20 version that appeared in the January 1989 issue of American SpaceModeling. The Mini-V2 is a simple model and was constructed using "scrap" materials laying around from other projects.
1. Two PNC-50 nose cones (2.75" long), one is used for the tail cone
2. BT-50 (4")
3. BT-5 (~2 ¼")
4. Used engine casings for centering ring (24mm, 18mm)
5. 1/8" balsa fin stock
6. Motor hook for mini motors
7. 1/8" wide elastic shock cord
8. Plastic streamer
9. Launch lug
10. Clay for nose weight
Tail cone assembly: Insert the tip of one cone into the BT-5 tubing and mark. Cut the end of the cone off (~1 3/16") so that the BT-5 tube will just fit. Also, cut off the end of the nose cone immediately before the shock cord attachment. Using ½" sections of the 24mm and 18mm casings, make a ring to center the BT-5 in the nose cone shoulder. This requires some peeling and, of course, other materials can be used. Install the engine clip so that the engine extends about 3/8" from the motor tube. Make a 3/8" long x 1/8" wide notch in the end of the boat-tail to accommodate the engine hook. Test fit the engine mount and make sure the engine hook works when installed in the tail cone (engine tube flush with the end of the tail cone). Glue it all together.
Nose weight: Add clay to the nose so that the CG without an engine is 3 7/8" from the tip of the nose cone.
So far, this model has flown 13 times on A10-3 engines. On the first try, the nozzle blew through. The Mini-V2 attained an altitude of about 10 feet and ejected on the ground. The second try was picture perfect. A ¾" x 3" plastic streamer brought it down safely about 50 feet from the pad. This is a good model for small fields. On the third try, the 1/4" lug bound on the 3/16" launch rod and the V2 stuck there. The rest of the flights have been successful.