Specifications for LVL1.2 ZP Balloon Actually Received from Global Western


Type: Constant-Altitude Zero Pressure
Material: Polyethylene
Thickness: 2 mil
Volume: Unknown, LVL1 White star estimates around 660 cu ft
Takeoff Payload weight: 5.4kg (12lbs)
Ceiling altitude with takeoff payload: 33000ft +- 2000 ft per Global Western
Mounting ring diameter: ~9.5 inches

Functional block diagram of balloon envelope system:
Note: Lower wired sensor will likely not be present for polyethylene duct vents, only for mechanical vents.

Actual shape measured flat on ground:

Payload Attachment


Two point primary attachment for the payload are required. Two points should be provided to attach rope to instead of just one, approximately 0.5m below the load ring. These should be connected to the envelope in a manner designed to prevent full (more than 360 degree) yaw axis rotation of a payload mounted 0.5m below the load ring.


A third auxiliary attachment point is the sensor probe tube at the top corner of the envelope. It should be connected to the envelope in a manner strong enough to withstand 12lbs of payload being supported against the streamer drag of the falling empty envelope.

Sensor Mounting

A probe tube is manufactured into the balloon in the upper corner of the envelope. The assembly is made of thin-wall 1” PVC tube plus a slip-fitting/female threaded coupler. This will allow a temperature sensor to be mounted inside of a threaded plug to be inserted and sealed with teflon tape just before launch.

Overflow Valve

Overflow valve will be a spring loaded-plate valve.

Flight Termination System Requirements

Method: The payload will release it's standard connection to the envelope load ring for flight termination. This will leave the payload attached to the top of the envelope with one rope, above the center of lift. This will immediately induce full envelope rotation around the center of lift, eventually stabilizing when the envelope is upside down. The helium will escape fairly rapidly, and completely, through the now upward-pointing overflow valve.

balloons/zp/lvl1.2resultantpurchase.txt · Last modified: 2011/11/15 04:14 by steamfire
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