2012-09-01 - Rich DeAngelis's EAC Viper

Flight Log - 2012-09-01 - Rich DeAngelis's EAC Viper

The Viper: A '70s kit offered to Estes Aerospace Club (EAC) members. It uses T motors. It is a good, economical flier with parachute recovery. The small 12-inch parachute is a good choice for this rocket, since it is limited to A-power only. I wouldn't waste the time using 1/4A motors unless it's extremely windy or you have an extremely small field, the larger motors are so much more satisfying.

This particular Viper was painted with Purple and Orange instead of the Purple and Yellow. I suppose that was because I had orange dope and no yellow, but that was 35 years ago, who knows?

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. With it’s most powerful A motor, I can’t seem to get this above the 200-foot mark. (Iris 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 Cape Hatteras Lighthouse in NC, the tallest lighthouse in the USA.

Flight Date:	2012-09-01
Rocket Name:	EAC Viper
Kit Name:	Estes - E.A.C. Viper {Kit} (0820) [1972-1986]
Flyer's Name:	Rich DeAngelis
Motors:	A3-4
Expected Altitude:	180.00 Feet
Wind Speed:	10.00 mph
Launch Site:	Fort Indiantown Gap, PA
Actual Altitude:	182.00 Feet

This was another good opportunity to compare the A3 and A10 motors. In general, the A10 is faster, but because of the higher drag forces at higher speed, doesn’t go as high – just like the theory goes.

This motor burned for 8/10ths second, peaking the acceleration at 10.6 Gs (half of the previous A10). The average G force was 3.6 (more than the previous A10). This got the Viper going to 65 mph (12 mph faster). By going slower for a longer time, it reached an apogee of 182 feet after a 2.8 second coast. As predicted, it was 34 feet higher than the “faster” A10.

The ejection was a tad early at 3.3 seconds, and during the last ½ second it fell 5 feet before ejection at 177 feet. With the well-deployed parachute it came back at 8 mph and landed 18.5 seconds later within 40 feet from the launch pad. I almost caught it in the air one-handed but a last-minute wind shift just over my head made me look like an un-coordinated nerd.

Stage	Motor(s)
1	Estes A3T-4

Post a Comment