The Sprint: This Astron Sprint is from the original '70s kit. It uses streamer recovery, but I changed it out for a small 8" parachute. It is designed for high-performance altitude flights, and generally requires longer-burning ejection delays for maximum height. The engine must be tape-friction-fit as this model does not have a metal motor clip. Instead it has the boattail end designed to reduce drag. This rocket was later given my "Iris" modification, which extends the body tube about 5 inches above the streamer/parachute bay, and allows for a payload with an Altimeter One to measure altitudes.
After this payload section was tragically lost when the screw-eye/balsa joint failed, I built a newer, lighter and smaller payload section. It is now 3-1/8" vs. 4-1/2", and weighs 9.8 grams. I certianly hope now I can get that extra 12 inches of altitude out of this bird and finally crack that elusive 1200 foot mark!
Originally, I replaced the flimsy crepe paper streamer with plastic one, but the plastic seems to stick to body tube because of static electricity, so I replaced it again with a small 8" parachute. With this parachute it descends at about 9 mph, soft enough for a safe grass landing. The rather small size should prevent this from drifting too much - a real problem considering the height it can attain. (The Iris altimeter payload is named after the Greek god of the rainbow. She is a messenger of the gods, linking the gods with humanity.) This rocket has flown higher than the NY Times Building in NY, the John Hancock Tower, and the Aon Center in Chicago.
| Flight Date: | 2013-05-04 |
| Rocket Name: | Sprint |
| Kit Name: | Estes - Sprint {Kit} (1249) [1970-1983] |
| Flyer's Name: | Rich DeAngelis |
| Motors: | B6-6 |
| Expected Altitude: | 465.00 Feet |
| Wind Speed: | 5.00 mph |
| Launch Site: | Halifax, PA |
| Actual Altitude: | 559.00 Feet |
It has been just shy of a year since I lost the original payload on the Sprint Iris. I have reconstructed a new payload section and was now ready for a test flight. The goal again was to reach a new altitude record and I hoped the slightly smaller payload section would allow that. First, I wanted to send up a lower-powered test flight to see how the winds were up there, so I selected a B6 motor. A previous B6 flight showed it could use a longer delay.
The motor lit and the rocket took off, travelling fast, straight and high. The one second burn peaked at 17 Gs at liftoff and averaged a healthy 6 Gs of acceleration. This got the Sprint to a speed of 125 mph, bleeding off for the next 5 seconds to an apogee of 559 feet – very good for a B motor. It then turned over and started to descend for the next 7/10 seconds, falling only 5 feet before the ejection charge fired at 554 feet. The B6-6 was perfect for this rocket.
The tiny 8” parachute opened and the rocket drifted down at 10 mph to land a few hundred feet away in tall grass. Flight time was 44.1 seconds. It was a perfect flight, but we had to spend at least a half an hour or an hour trying to locate it in the grass, very frustrating because it was such a perfectly clear and cool day for flying. I realized I need to pay closer attention to where this rocket landed.
| Stage | Motor(s) |
|---|---|
| 1 | Estes B6-6 |
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