Specifications for LVL1.1 ZP Balloons

Envelope

Type: Constant-Altitude Zero Pressure
Material: Polyethylene
Thickness: 0.75 mil to 2 mil
Volume: As required
Takeoff Payload weight: 5.4kg (12lbs)
Ceiling altitude with takeoff payload: 250mb (11800m / 38600ft)

Functional block diagram of balloon envelope system:

Top envelope Sensor: Direct Connect
Middle Envelope Sensor: 1x Tee
Bottom Envelope Sensor 1: 1x Tee
Bottom Envelope Sensor 2: 1x Tee
Vent tube will extend out the vent valve, and the end of the tube must be pointed up.

Payload Attachment

Primary

Two point primary attachment for the SpeedBall payload is required. Two points should be provided to attach rope to instead of just one, not more than 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.

Valve Clearance

The primary supports should allow X clearance for the valve operating mechanism.

Auxiliary

A third auxiliary attachment point should be provided on the outside at the top 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 System

An assembly of wires, pneumatic tubing and sensors will be suspended from the center of the envelope. Sensors are detailed at the Balloon Sensor Nodes v1 page. The total weight of this assembly will be between 150g and 200g. The overflow valve with have a sensor to indicate open/closed status. The weight of these sensors are to be considered part of the 12lb payload.

Overflow Valve

Overflow valve should standard polyethylene duct on all balloons. LVL1 may carefully

will be constructed and installed by LVL1 White Star team to be built into the balloon by the manufacturer.
Dimensions: Valve assembly diameter will be smaller than the inner diameter of the load ring.
Sensor Porting: Sensor wires and tubing will exit the envelope through dedicated, marked, holes provided in the vent. The sensor wires/tubes will be supplied already threaded and sealed through the vent assembly.

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. Please specify an inversion rope length and diameter that is appropriate to allow the payload to swing in all directions, relative to the envelope, without damaging the envelope.

balloons/zp/lvl1.1.txt · Last modified: 2011/01/07 04:13 by bradluyster
 
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