Sunday, January 02, 2011

Review: A trio of post-BAR LPR designs

This review covers three LPR rockets that I built after becoming a BAR - The GI Joe, the Tiger Shark, and the XR-71 Green Burd.


GI Joe


This is a scratch rocket built with parts from an Estes "Designer's Special". It features a BT-55 to BT-50 transition and a rear "nozzle".

Construction:

This rocket was built around the mid 80's and there is nothing unique in its construction. The nose cone is plastic and the transition and nozzle are paper wraps. These wraps and the fin pattern were all provided in the Designer Special.

I added stickers from one of my son's GI Joe toys to complement the camo paint job.

Flight:
This flew on A, B, and C motors. There were several flights even though there is only one in the my flight log.






Tiger Shark

The Tiger Shark was also built with parts from an Estes "Designer's Special". It includes a BT-20 main tube and a BT-50 payload.

Construction:
This rocket was built around the mid 80's and there is nothing unique in its construction. The nose cone is plastic and the transition is balsa. The fin pattern was also provided in the Designer Special. Reflecting its name, the paint scheme resembles a tiger and a shark.

Flight:

This flew several times on A and B motors. The rocket has been inactive because it is just too much of a pain to pack a chute in the BT-20.

XR-71 Green Burd

This is a scratch built jet fighter that is roughly patterned after the SR-71 Blackbird. As you can see, I wasn’t terribly creative in the naming department.


Construction:

This rocket was also built around the mid 80’s after I became a BAR. The main body tube is BT-50 and the wing-mounted tubes are BT-20. The main nose cone was originally constructed from a balsa bulkhead and a plastic missile from one of my son’s toys. I have since replaced it with a plastic Estes cone. The nose cones on the pods are balsa and there is a small piece of BT-5 mounted in the rear of each pod. It has an 18mm motor mount and an old rubber band shock cord. The main wings are 3/8” balsa. The long forward sections and the stabilizers mounted on the pods are 1” balsa strips that taper from 9/16” to 3/16”. Finally, the cockpit was carved from a section of ½-oval balsa (kind of like oblong ½-round molding).

After performing a swing-test, I added a couple of lead pellets as nose weight. After RockSim-9 came out, I confirmed its stability the newfangled way.


Finishing:
I started to paint the top of the rocket in Day-Glo green and the bottom solid gray. Even back then, I tended to 'use what I got'. I mixed the Day-Glo green with some regular green (both Testor’s) so I could transition from a darker green on the body to a lighter green on the fins. However, I ran out of Day-Glo paint and, rather than replace it, the body ahead of the side fins is camo green. You can see the additional white and Day-Glo orange trim. The protruding BT-5 tubes on the pods are painted gold.

 

Flight:
In recorded history, it has flown twice on C6-5's and once on a B6-4. The rocket exhibits the slow roll/swooping profile that is typical for winged rockets. All flights were successful.

Summary:
This design is not unique, but is much more interesting than a 3/4FNC rocket. The tapered slats worked out nicely. No comments on the paint job, please.