Specifications for LVL1.2 ZP Balloons

Envelope

Type: Constant-Altitude Zero Pressure
Material: Polyethylene
Thickness: 2 mil
Volume: As required
Takeoff Payload weight: 5.4kg (12lbs)
Ceiling altitude with takeoff payload: 250mb (10350m / 33950ft)
Mounting ring diameter: ~10 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.

Payload Attachment

Primary

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.

Future Valve Clearance

The primary supports should allow clearance for the a retrofitted mechanical valve operating mechanism that extends 8” out of the ring.

Auxiliary

A third auxiliary attachment point will be on 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 will need to be manufactured into the balloon in the upper 1/4 of the envelope. This tube assembly will be provided by LVL1 White Star for all balloons requiring it. 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.

The coupler will be provided with a .1” deep groove, 1/2” wide, made below the hex wrench flats to allow a hose clamp to be securely seated.

The weight of the sensor, batteries and tube is estimated to be approximately 110g.

Overflow Valve

Overflow valve should be standard polyethylene duct on all balloons. LVL1 may carefully remove the duct and replace with a different design on certain flights. Global western has agreed to provide LVL1 with a few extra cardboard rings cut to the same dimensions as the flight rings, for future vent R&D.

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.

Inversion rope: The rope will be provided and attached by the customer after receipt of the envelope.

balloons/zp/lvl1.2.txt · Last modified: 2010/11/11 00:09 by steamfire
 
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