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====== Balloon Data ======

Totex balloon Data:

^Balloon Weight (gr)^200^300^350^450^500^600^700^800^1000^1200^1500^2000^3000^
|Diameter at Release (cm)|117|123|125|130|133|142|146|150|157|179|185|195|212|
|Volume at Release (cu.m)|0.83|0.97|1.03|1.1|1.22|1.5|1.63|1.76|2.01|2.99|3.33|3.89|4.97|
|Gross Lift (gr)|960|1110|1185|1335|1405|1720|1870|2020|2310|3440|3830|4470|5720|
|Nozzle Lift (gr)|760|810|835|885|905|1120|1170|1220|1310|2240|2330|2470|2720|
|Payload (gr)|250|250|250|250|250|250|250|250|250|1050|1050|1050|1050|
|Recommended Free Lift (gr) |510|560|585|635|655|870|920|970|1060|1190|1280|1420|1670|
|Rate of Ascent (m/min)|320|320|320|320|320|320|320|320|320|320|320|320|320|
|Diameter at Burst (cm)|300|378|412|472|499|602|653|700|786|863|944|1054|1300|
|Volume at Burst (cu m)|14.1|28.3|36.6|55.1|65.1|114.2|145.8|179.6|254.3|336.5|440.5|613.1|1150.3|
|Bursting Altitude (km)|21.2|24.7|25.9|27.7|28.4|30.8|31.8|32.6|33.9|33.2|34.2|35.4|37.9|

Its worth noting that the data above is based on the use of Hydrogen rather than Helium.

Hwoyee Balloon Data:

^Balloon Size (g)^100^300^350^500^600^800^1000^1200^1600^2000^
|Neck Diameter (cm)|≤4.5|≤6.4|≤6.4|≤6.4|≤6.4|≤6.4|≤7.7|≤8.3|≤8.3|≤8.3|
|Diameter at Burst (cm)|180|380|410|500|580|680|750|850|1050|1100|
|Average Burst Altitude (m)|16000|19000|21000|27000|28000|30000|32000|33000|36000|38000|
|Average Ascent Rate (m/min)|200|≥340|≥340|≥340|≥340|≥340|≥340|≥340|≥340|≥340|

The Balloon **Gross Lift** is the lift generated by the volume of Gas.  Hydrogen has a density of about 0.09 kg/cu m and air about 1.2 kg/cu m at normal atmospheric pressure - generating a lift of a bit over 1.1kg/cu m. Helium has a density of about 0.17Kg/cu m - generating a lift of a bit over 1.0Kg/cu m.   Subtract the **Balloon Weight** plus the **Payload** weight form the **Gross Lift** to give the //free lift//. The **Recommended Free Lift** gives a **Rate of Ascent** of 320m/min (a bit over 1000ft per minute).

Heavier payloads can be carried than the values above - this will either reduce ascent rate, burst altitude (if the balloon is further inflated to compensate) or both. The following spreadsheet allows you to calculate the affect on burst altitude and ascent rates of various levels of fill and payload. To use: choose the balloon size and fill in the payload weight - then adjust the launch diameter until you get the desired ascent rate (normally about 320m/min) -  the volume at launch will tell you how much gas you will need.

{{guides:burst3.xls|:guides:burst3.xls}} by [[ukhas:members#Steve Randall (RocketBoy/G8KHW) - UK| Steve Randall]]


[[http://www.srcf.ucam.org/~cuspaceflight/calc/|CUSF Online calculator]]

[[http://nearspaceventures.com/cgi-bin/ascent.pl|Online Ascent Calculator (imperial units)]]




====== Keep it simple beginners table ======

^Balloon size^Payload weight^Helium needed^Free lift^aprox. Burst^ParaChute size^
|300g|150g|0.84 cu m|410g|84,000ft|18"|
|500g|250g|1.29 cu m|570g|93,000ft|18"|
|800g|400g|1.84 cu m|690g|108,000ft|24"|
|1000g|500g|2.23 cu m|780g|112,000 ft|24"|
|1200g|600g|2.62 cu m|890g|115,000 ft|24"|
|1500g|750g|3.21 cu m|1040g|117,000 ft|30"|

(the above assuming about 1000ft/min ascent rate)         

"Free lift" is the amount of extra lift the balloon will have after lifting itself and the payload - its the thing that sets the ascent rate.  Free lift is the extra weight that should be added (to the payload weight) when filling the balloon to nutral boyancy.  Don't forget to take the extra weight off before launch.

















====== Helium Cylinder Data ======

^Size^Volume (cu m)^Approx Price^ Price /cu m^ 
|Small| 0.25 | BOC (Disposable Cannister)| |
|Large| 0.4 | BOC (Disposable Cannister)| |
|L 10| 1.81| LBG | |
|PT 10| 1.81 | Air Products £90 via Click4Balloons.co.uk | £49.70 |
| V | 1.81 | BOC £74.99 via BalloonHeluim.co.uk| £41.43 |
|N 10| 2.61 | £105.00 Air Products via Click4Balloons.co.uk | £40 |
|G 10| 2.61 | £89.99 BOC via BalloonHeluim.co.uk | £34.34 |
|L 20| 3.62 | LBG | |
| T | 3.62 | BOC £105 via BalloonHeluim.co.uk | £29 |
|N 20| 5.2 | Air products £130 via Click4Balloons.co.uk | £25 |
|G 20| 5.2 | BOC £116.99 via BalloonHeluim.co.uk | £22.50 | 
|N 30| 7.82 | £165 Air products via Click4Balloons.co.uk| £21 |
| L | 9.0 | BOC £165.95 via BalloonHeluim.co.uk (Jumbo) | £18.43 |
|L 47| 9.05 | LBG | |

Retail inc. VAT prices displayed on websites as of 08/06/2017 - see rental prices to get the whole picture.

28/09/2016:   * A single N20 (5.2cu m) of Air Products Balloonium from Click For Balloons: £115.00inc VAT - includes 3 months rental.
* A single G20 (5.2 cu m) of BOC Balloon Gas from BalloonsHelium.co.uk: £110.99inc VAT - includes 28 day rental.
* Both products are quoted as 97% Helium by their manufacturers.
* A single G20 of BOC Hydrogen via BOC account: £94.18 inc VAT and 28 day rental