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: | C6-7 |
| Expected Altitude: | 1,168.00 Feet |
| Wind Speed: | 5.00 mph |
| Launch Site: | Halifax, PA |
| Actual Altitude: | 1,084.00 Feet |
It was now time to go for the record altitude again. The previous B6 flight went well and showed that the new, smaller payload could very well make the difference and let this model break 1200 feet.
The C6 motor fired up and accelerated the Sprint to a record-high 19.4 Gs at liftoff. The motor burned for two seconds and averaged 4.8 Gs of acceleration, higher than any other C motor in this rocket. This brought the Sprint to a new speed record of 213 mph!
The ejection charge fired after 6.8 seconds, just a bit early, stopping the rocket’s upward coast a little early, at 1084 feet up. In the last 1/10 second the rocket halted its climb, gaining the last 23 feet of altitude where it reached its apogee of 1107 feet, far short of the record.
A good parachute brought this rocket back at 12 mph, landing in the tall grass again after a 67.3 second flight. It was a perfect and a spectacularly high flight.
This particular C6 motor was a fast burner, creating record acceleration and speeds, but that was likely what prevented it from reaching a new altitude record. A slow burner could have done better.
This time I noted exactly the line from where I was standing and where the rocket landed. My wife, standing about 400 feet to the East, also noted a line where the rocket landed. We were able to pinpoint the exact area of the landfall, yet when we arrived there, the rocket was nowhere to be seen. It took another half hour before the rocket was found, after I gave up looking in circles and started an exhaustive (and exhausting) search in a large X-Y grid pattern. And yes, the rocket did land where we thought it did, but was still hidden in the grass.
I decided it was time to fly only larger rockets in this field today, and I couldn’t risk any multi-stage rockets because the smaller booster stages would most certainly disappear from sight.
| Stage | Motor(s) |
|---|---|
| 1 | Estes C6-7 |
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