For us old guys and other nostalgia fans, I cleaned up and examined my Park Plastics rocket that I played with back in the 60s. The set had two of the red and blue rockets seen in the photo, a small red plastic funnel and a yellow pump with a red hold-down and handle. One of the rockets had its fins crack off at the body seam while it was still being flown. You can see some cracks starting in the plastic near the nozzle in the photo of the other rocket. The fins extend slightly below the nozzle and the ends are bent to make the rocket spin. The plastic fins are also warped, possibly from spending too many years in a hot attic. There are water fill lines in the red nose marked 75 and 100 ft. That seems optimistic to me from what I remember of my luck with it.
The pump had a very short tube that fit into the nozzle, and a rubber washer that sealed against the bottom of the nozzle. That tube eventually broke off, making it almost impossible to seal the rocket anymore. Too bad I didn’t know how to fix it back then. A longer launch tube might have made a difference. I have the rockets and funnel but I haven’t been able to find the pump so I suspect that it was lost in one of several floods that my childhood house endured.
Here is the data on the rocket as best as I could measure it. Maybe someone is interested in figuring out just how well it could have been flown.
The fin is marked “PARK PLASTICS LINDEN N.J. PAT. NO. 2,732,657”
weight empty: 15 grams
total volume: 69 ml.
water filled to 100 ft. mark: 20 ml.
water ratio at 100 ft. mark: 29%
length nose to nozzle: 5 1/2 inches (140 mm.)
center of gravity empty: 2 3/4 inches (70 mm.) from nose
diameter at center seam: 1 3/8 inches (35 mm.)
nozzle opening: 11/64 inches (4.5 mm.)
nozzle flange diameter: 15/32 inches (12 mm.)
width at fins: 2 1/2 inches (63 mm.)