Krystal: Success!

Success!

Krsytal flew well! Twice, to ensure it wasn't a fluke. All four engines lit both times: three in the booster, one in the sustainer. Booster pods deployed their chutes just fine.

Cliff asked me to write an article for the'Clips.

Krystal Ready to Fly

I finished Krystal yesterday evening, attaching the pair of 30cm chutes to the booster pods' shock cords. In retrospect, I should have gone with BT-50 pods, to allow for at least a nylon chute and a heat shield, maybe even 45cm chutes.

Tomorrow's the big day, then: first flight. I'm hoping to get some good photos and maybe a slow motion video (if Cliff's at the launch). Watch this space and the Rocket Works Web site!

Minor Snag: Nose Cone Interference

A minor snag on Krystal, at least slightly anticipated. The pod nose cones interfere slightly with the booster main body tube. I thought this might happen: I probably should have just built a shim onto the pod in the design. I caught this flaw during test fit, before gluing the pods to the booster, so it's easy to add the shim: cut a couple of thin strips of 1/32" balsa (one for each pod), paint the edges flat black to match the pod. Shouldn't be a big problem, just a minor delay.

Krystal Update

I mentioned this rocket called Krystal that I'm building, in Display Nozzles and Other Distractions and The Joys of Tools. For details on the rocket, see its section on the Rocketworks Web site.

Painting is now almost complete. The final color scheme has a red body, gold fins with a few red highlights, black pod body, gold nose cones and transition, and white vent fairings. The only bit left is to paint the fairings.

Assembly remaining: attach the pods, parachutes, and parachute protectors.

I discovered what would have been a big mistake last night while painting. I'd not yet glued the sustainer motor mount into the body tube! The fit is pretty tight, so it didn't simply fall out, nor did the rocket slide around while painting (I use a stick inside the motor mount tube to hold the rocket). I'll correct the oversight this weekend, I expect.

Epoxy and Wrap Edges

It worked!

I was very nervous about securing the few remaining edges and corners of the main tube wrap, given my experience with melting CyA when the plastic is under any stress (radial or tangential). Last night, I tried 60 second epoxy to secure a few of the errant edges: seems to work very, very well. Plan now is to finish those up, then get the tunnels sized, shaped, and sealed, and move on to whatever's next.

Display Nozzles and Other Distractions

I've been working on the display nozzles. That might seem like it wouldn't take much time: just glue them together, assemble the base (to which you attach the nozzles, which is then inserted in the bottom of the rocket), and paint. Well, the base was a bit snug inside the bottom of the rocket, so it was time to sand it down. I then wanted to ensure the base didn't fray, so I applied a light coating of thin CyA, which, as expected, required a bit more sanding. I've finally masked off the nozzle attach posts and sockets, and once the weather clears I'll prime and paint.

I'm also distracted by an interesting scratch-built two-stage rocket, unrelated to the Saturn, that's required some engaging engineering solutions. (See the October 18 entry, The Joys of Tools for one example, and there've been numerous others.) That rocket, called Krystal, is now mostly assembled and in primer. It needs some sanding of the primer (especially the booster fins and the interstage transition, which will be tricky—for which reasons you'll have to await a future posting), then painting. Painting won't be trivial: dark red body (booster and sustainer), gold fins and interstage, white interstage vent fairings and nose cones, gold pods.