Impromptu

Well, instead of Wednesday, I had the girls Tuesday this week. My ex's hubbie (there ought to be a term for that. Step-brother-in-law?) was having fun with kidney stones, and it wasn't going to be a fun time for the girls to hang out in the ER waiting for their step-dad to pee rocks.

I know, I'm no doubt in for the same visit sooner or later, all the soda and booze I drink. And I'm a total baby about pain. Em describes her step-father, a former Marine, as 'tougher than a burnt chocolate chip cookie,' a description I doubt will ever be attributed to me.



Anyway, we hit Hobby Lobby. 30% off on rocket kits through May. Picked up a Skywriter (the Scribble V) and a Big Daddy (the first 3" diameter rocket for us).

As we were leaving the Hobby Lobby, a woman pulled her car up by me and told me 'I was watching you in there, and I wanted to commend you. You are such a patient father.' I thanked her, and when she said, 'It takes a lot,' I confessed that it sometimes takes more than I've got. Still, what a sweet compliment.



Thing is, it was really a very easy trip through Hobby Lobby. At the end, after Em talked me into buying her fabric for a doll dress, Mo wanted modeling clay and I agreed. Then she wanted Silly Putty. Then a candy bar. She had to choose, and she changed her mind about ten times. It wasn't stressful, I just wouldn't let her have more than one, and like all of us, she wanted to have her cake and eat it too.



I was worried she'd eat the modeling clay, and told her if I saw it go to her mouth even once it'd be gone forever. This seemed to make the Kit-Kat look better for a minute or two.

Then to the Purple Park at Mo's request. Kites, not rockets, it was way too windy for rockets. It also clouded up quite a bit, and I wondered if we'd pull a Ben Franklin, but there was no sign of lightning so I decided not to sweat it.



I got the seven-footer up and let it out to the limit of the 500 foot line. Blistered my thumb with the friction as a matter of fact. Couple that with the tick bite on my ass I got the other day and kites are looking pretty dangerous.

I put new streamers on the airfoil kite, too. Rainbow ribbon from Hobby Lobby to replace the cheap-ass easily tangled plastic streamers it came with.



I try to keep Mo from eating her sidewalk chalk, but she likes the way it colors more densely when wet, so she licks it more than I'd like.



Back home, Mo asked for her modeling clay and proceeded to make 18 smiley faces. And not once did she try to eat the clay (I know this shouldn't seem impressive, but it is).



While she was doing that, I started debating about what to do with this Big Daddy kit. I have a design for the decals in mind: a jazz theme this time. I think I'll scan Daahoud from the Real Book and run the head of that over the rocket. Maybe spiral it, maybe just wrap it around.



I might work up some photos of the pantheon: Bird, Sonny Rollins, Miles, Coltrane, etc. The rocket's name will be Bebop, and the base coat of paint will be metallic copper.



The kit comes with laser-cut fins, but they're balsa fins and I prefer basswood. Basswood is heavier, but much, much stronger. I worried, though, that such a short rocket could easily become tail-heavy and unstable in flight. Plus, I had these laser cut fins ready to sand and bevel, complete with through-the-wall tabs to the motor mount.



So then I think maybe I'll fiberglass them. But you're rapidly back to making the ass end of the rocket heavy: if the center of gravity is behind the center of pressure, it's like a car fish-tailing. I think I'll brush a thin coat of epoxy onto the fins and let it go at that.



The kit instructions tell you to tie the rubber-band type shock chord they give you through a slit in the forward centering tube, but be serious. Rubber bands melt easily. I tied 400lb test Kevlar line around a carbon fiber BT50-60 centering ring and reinforced that with another carbon fiber ring ahead of it. I also subbed out the motor mount Estes provides for one that gave me more room. I ditched the engine hook in favor of friction/tape as motor retention, and I wanted the motor tube to protrude further than it could without shrinking the fin tabs substantially on the provided fins.



I'll also substitute the parachute. Estes provides a 24" parachute, but it's a plastic dude and I have rip-stop nylon 'chutes that are much more reliable.



I also haven't decided whether to do epoxy-clay fillets. They add strength but also weight. And coating the fin tabs with epoxy and then sliding them into the fin slot builds a pretty nice fillet of straight epoxy.



I figure if the balsa fins turn out to be the liability, I can order some 3" tubing from Balsa Machining and make something to go with that monster nose cone.