Balloon DATA
Balloon Parameters explained. (© Random Engineering 2017)
Name: e.g. Hwoyee HY-100, Totex TA-1500, Pawan CPR-800. The letters denote the manufacturer and type of balloon, the numeric part designates the nominal weight of the balloon.
Colour: Colour of the latex used. As standard only the smaller balloons are offered in colours other than natural (uncoloured - which is a creamy white). The small pilot balloons are typically red.
Weight: This is the approximate weight of the balloon. Totex and Pawan specify an average weight, Hwoyee specify a weight range.
Neck Length: The length of the thicker portion of the neck – used for filling and tying off the balloon.
Neck Diameter: The approximate diameter of the neck when opened out (its folded flat in packaging).
Flaccid Body Length: the length of the empty balloon when laid out.
Barely inflated diameter: the diameter at which the balloon envelope first fills out completely (i.e before becoming taught).
The remaining parameters can be viewed as a reference set of values:
Lifting Gas: Often this isn't explicitly specified (but can be worked out from the gross lift and volume at release). Typically Hydrogen is used as it provides the best results.
Payload Weight: the weight of the reference payload. For pilot balloons (usually those less than 200g) this is typically 0 (these balloons are visually tracked), for balloons between 200g and 1000g the Payload Weight used is typically 250g and for balloons above that 1050g is typically used.
Volume at release: the amount of Lifting Gas to achieve the Rate of Ascent with the Payload Weight.
Diameter at release: The diameter of the balloon when filled with the above amount of gas – typically manufacturers just assume a spherical shape.
Gross Lift: The total lift provided by the Lifting Gas enclosed by the balloon (i.e. The weight of the displaced air less the weight of the lifting gas).
Nozzle Lift: the lift measured at the balloon neck (without the payload attached) – i.e. the Gross Lift less the Weight of the balloon itself. Nozzle Lift must always be more than the payload weight for obvious reasons.
Free lift: the lift left after taking the payload into account. Free lift = Nozzle Lift – Payload weight.
Rate of Ascent: Average rate of ascent with given payload and gas volume.
Diameter at Burst: as the title implies - the diameter of the balloon at the point it is expected burst.
Bursting Pressure: The external atmospheric pressure at which the balloon is expected to reach its burst diameter when filled as specified (i.e. Lifting Gas & Volume at Release) and carrying the specified Payload Weight.
Bursting Altitude: The altitude at which the balloon is expected to reach its bursting diameter using the standard atmospheric pressure to height model.
Things that aren't specified by the manufacturers:
Maximum lift (neck load): This will vary from manufacturer to manufacturer as neck designs vary considerably. As a guide we are generally unconformable exceeding 5 times the balloon weight. In some instances payloads of up to ten times the ballon weight have been used on small balloons without failure – but these should be seen as working at the extremes.
Page Updated 3rd March 2017
(© Random Engineering 2017)
Balloon Datasheets
