Flight Log - 2013-06-30 - Rich DeAngelis's Sprint

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: B6-6
Expected Altitude: 465.00 Feet
Wind Speed: 4.00 mph
Launch Site: Fort Indiantown Gap, PA
Actual Altitude: 555.00 Feet

Another test flight using long-delay motors. This time I changed the parachute back to my usual 8” hexagon.  (Parachutes are so much easier to pack then the stock paper streamer.)
The B6 flexed its muscle by thrusting off the pad with 16.5 Gs of acceleration, burning for one full second and sustaining 5.9 Gs. After that the Sprint was travelling at 123 mph and coasted for another 5.3 seconds to apogee of 555 feet.
Turning over at apogee, only 1/10 second went by before the ejection fired 5.4 seconds after thrust, with the rocket only falling 4 feet. The small 8” chute opened cleanly and the rocket came back at 15 mph.  Flight time was 31.7 seconds.  This was the second very successful flight of the Sprint today, and it wouldn’t be its last.

StageMotor(s)
1Estes B6-6

 

comment Post a Comment