So I'm doing the numbers, and I'm getting altitudes on the order of 700+ feet for a boosted dart that looks like one of Gregorek's modified Alphas on a 2-liter water rocket. (Using Cd = 0.55, which is measured from many flights of unmodified Alphas.) Would like to prove it, and recover the boosted dart... without killing anyone. Problem is, I have the inside volume of an Alpha, and about 40 extra grams to fool around with.
I've used altimeters before, but never for deployment. It's about $125.00 riding on every attempt at Adept. Can anyone suggest a cheaper option? If this were a regular rocket, I'd use pyrotechnic mechanisms, but it's hard to synchronize everything on a water rocket.
Also, been thinking of flash paper as a deployment charge. It's cleaner than BP, and available in magic shops. It can be stored damp. I remember from an old nerd shop (Natural Wonders?) science experiment that the material will produce an audible report from an unsealed PVC tube. . Comments?