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: | 2013-06-30 |
| Rocket Name: | Sprint |
| Kit Name: | Estes - Sprint {Kit} (1249) [1970-1983] |
| Flyer's Name: | Rich DeAngelis |
| Motors: | C6-7 |
| Expected Altitude: | 1,168.00 Feet |
| Wind Speed: | 4.00 mph |
| Launch Site: | Fort Indiantown Gap, PA |
| Actual Altitude: | 1,183.00 Feet |
This was going to be the day, I could feel it. It was sooo…hot and humid and the winds were very light. I knew in this thin air I could finally break the 1200 foot mark, and still have this tiny rocket fall in the field. To make it more likely to happen just like that, I changed out my normal 8” hex chute for an even smaller 6” square chute – yes – square, with only 4 shroud lines.
The Sprint leapt off the pad at a powerful 18.6 Gs of acceleration, and for the 1.9 seconds of thrust it averaged 5 Gs. It attained a top speed of 209 mph before coasting for 6 seconds. Bummer the ejection fired a full second early, stopping this blistering pace but only after a rather long ½ second, where the rocket climbed an additional 12 feet, peaking at an apogee of 1183 feet. Another second of delay could have allowed an additional 17 feet and a new record altitude, but it was not meant to be.
Although it was way too high for me to see, someone else spotted the rocket’s little brown 6” parachute shimmering in the sunlight. It must have caught a thermal because the rocket descended at 11 mph but achieved a record-breaking flight duration of 76 seconds. Great flight!
| Stage | Motor(s) |
|---|---|
| 1 | Estes C6-7 |
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