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The first thing that struck me is that the American flags are backwards. The unit came complete with removable engine bells, though, that I managed to retain for display purposes. Only the four outer ones are there, but it still looks cool, and the rocket is small enough to make a desktop discussion piece. The bird has the shape of a Saturn V first and second stage with an absolutely huge payload fairing. While such vehicles were proposed to boost large payloads into LEO for construction of a space station and missions to Mars, the closest one to ever fly was the Saturn INT-21 for Skylab which looks little like my bird.
The unit came appart in three pieces as shown at left. This made adding nose weight (¾ oz. of lead and clay!) to the payload section, the recovery system (12" Estes 'chute, 12" each of 1/8" elastic and Pratt safety line) to the second stage and the motor mount (13 mm) to the first stage a snap. The first stage is just the right size for a BT-20, and while I considered 18 mm motors for her, they weighed too much.
She's a little thing, only being an inch in diameter and just under seven inches long (excluding the bells), so the 1/8" launch lug looks huge tacked to her side. Massing about 12/3 oz. dry, she was gonna be a real missile if she's unstable. I gave her enough margin to meet my stubby bird ROT (static stability need only be 1/10th L/D) and RockSim claims she's more than OK, but it still doesn't "feel" right. If she was stable, her low Cd would let her perform well. The ½A3 does have a maximum liftoff weight of 2 oz., so I'll have to run her on the A10 first. I was wanting to do that with no one else around!
But it wasn't to be. She languished in my rocket box for weeks before I got up the nerve, and I just wasn't going to wait any more. I loaded her with the big A10, wrote "HEADS UP!!!" on the flight card, and after some sidelong looks from the RSO, off she went. While she did wobble quite a bit, she was stable, and the flight went just about as well as I could have hoped for. She even weathercocked a bit, though I suspect it was rod whip. The 'chute had some second thoughts about inflating, but eventually did, and even though she landed on gravel, not a bit of damage. Ha! I can't believe this thing flies!
Her next flight wasn't quite so good; she was stable off the pad on the A10-3, but at ejection the 'chute didn't open. My fault, I didn't prep it properly, not inflating it prior to packing. While she came down fast, there was no damage and she was ready to go again. Another A10-3 produced a stable flight and a late-opening 'chute; a little corn starch is probably in order.
Her fourth flight was on the A3, which I didn't even bother to check when I first ran her simmulations, believing the four second delay to be too long. While it is a bit after apogee, both in software and in practice, its well within the realm of safety. This motor is a lot better for her than the A10; the extra altitude and long coast makes her seem like a real rocket, and she doesn't seem to wiggle as much. I had applied some powder to the 'chute prior to that effort, and while it still took a while to open, it wasn't as bad. She spit her motor, so descent rate was lower than usual. The safety line is starting to unravel, and the tangle after this flight is Gordian in nature, so I'll be rebuilding the recovery system shortly. Gotta tell ya that I never expected to find this girl worthy of such an effort, the A3 makes her a great little bird.
| Engine(s) | AGL (ft.) | Speed (ft./sec.) | Accel (Gs) |
|---|---|---|---|
| ½A3-2 | 60 | 60 | 13.6 |
| A3-4 | 215 | 105 | 9.7 |
| A10-3 | 200 | 100 | 22.7 |
| B7-6 | 890 | 265 | 25.8 |
