Super Loki Dart & Booster

There are several different styles of super-loki boosters and darts with slightly different specifications. Ours had a designation PWN-10D. Typical specifications are shown below.

In each case, the lower stage (the booster) provides a very rapid acceleration to about mach 5. Once the booster engine cuts off, the dart and booster separate and the dart continues to coast for about 2 minutes. The upper stage (the dart) carries the instrument payload and an ejection charge, but does not include additional propellant.

Launch Weight: 68 lb
Burnout Weight: 31 lb
Instrument Dart Weight: 18 lb
Booster Weight: 50 lb
(A 4.5 lb ballast weight is added to the booster for launches near populated areas. The ballast gives the booster aerodynamic stability on descent)
Propellant: ammonium perchlorate based
Burn time: 2.1 seconds
Height, Total: 10.5 ft
Height, Booster: 6.5 ft
Height, Instrument Dart: 4 ft
Booster diameter: 4 inches (excluding fins)
Altitude for booster/dart separation: approx 30,000 ft
Maximum Altitude (instrument dart): approx 250,000 ft
(185,000 ft w/ballast)
Time to apogee: 110 to 120 seconds
Top speed: 1 mile/sec (approx. mach 5)
Spin rate during ascent: approx 16 rev/sec (1000 rpm)
Payload: (main portion) 1 11/16 inch dia. x 11.2" long
Payload descent time: to 20km: 30 - 45 min with 10ft starute
to ground: 1.5 + hours (weather dependent)
Max Payload Weight: 4 lb (but is typically about 1 lb)
Initial acceleration (vertical): 60 g's (up)
Initial coasting acceleration due to air resistance: approx 30 g's (down)
Maximum centripetal acceleration on payload: 20 g's (horizontal)
Acceleration upon ejection: 100 to 250 g's along trajectory (depending on who you ask)

Super Loki Launch Rail
The Super-Loki is launched from a 12 ft rail which is raised to near vertical just before launch. The twist in the rails gives the rocket a 16 revolution per second spin as it exits the rail. The rocket clears the rail approximately one tenth of one second after ignition.

Click here for a still picture of a Super Loki Launch (approx. 110 Kbytes)
Click here for another still picture of a Super Loki Launch (approx. 61 Kbytes)
Click here for a schematic of the dart assembly

Click here to watch a loki launch (0.85MB, MOV) or here for an AVI file (6.7MB, AVI)

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