Differences

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--- projects:splat [2011/10/19 21:50] – [Test Balloons] rocketboy
+++ projects:splat [2023/02/19 12:10] (current) – [Project aim] rocketboy
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 ====== SPLAT – Super Pressure Low Altitude Tests ======
-{{:projects:splat.jpg|}}
 ===== Project aim =====
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 Confirm Super Pressure balloon theory by using large “foil” party balloons and lightweight payload.
-Currently the project is in the balloon testing phase - test rig with 10Kpa differential pressure sensor under construction.
+Currently the project is in the balloon testing phase - test rig with 10Kpa differential pressure sensor constructed and used to burst test a balloon.
+This Project dates from around 2010.
-===== Payload =====
-  * Battery 1100mAH Li-ion   24g
-  * GPS – WD-G-ZX4120 + patch antenna - 20g
-  * PIC18F2680 + NTX2 + LE33 + DS1820 - 18g
 ===== Super Pressure Musings =====
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 The ascent rate will be more or less linear until the envelope fully inflates (this is because the drag effects due to increasing size of the balloon cancels out that of the reducing air density). Beyond that the ascent rate should continue to reduce as the float altitude is approached.
-A spreadsheet SP pressure calculator {{:projects:float1b.xls|float1b}} has been written to calculate float altitude and differential pressure to confirm this theory.
+A spreadsheet SP pressure calculator {{:projects:float1g.xls|float1g}} has been written to calculate float altitude and differential pressure to confirm this theory. Previous versions here:{{:projects:float1b.xls|float1b}}  {{:projects:float1c.xls|float1c}}  {{:projects:float1d.xls|float1d}} {{:projects:float1e.xls|float1e}}
@@ Line 50: / Line 46: @@
 ==== Test Balloons ====
-The 36” Qualatex balloons to be used have a mass of 37g and have a measured volume of approx. 0.10 (measured by helium lift) to 0.11cu m (measured by water fill) when nicely "full".  Two balloons have been pressure tested - the first with a manometer the second with a pressure sensor MPX5010.  The results were burst at about 4.7Kpa (0.7PSI) and 5.4Kpa (0.8PSI) respectively. Testing suggests volume increases by about 33% at burst (due to stretch). Both tests resulted in a diagonal rips - see pictures.
+The 36” Qualatex balloons to be used have a mass of 37g and have a measured volume of approx. 0.10 (measured by helium lift) to 0.11cu m (measured by water fill) when nicely "full" (i.e. not yet stretched).  Two balloons have been pressure tested - the first with a manometer the second with a pressure sensor MPX5010.  The results were burst at about 4.7Kpa (0.7PSI) and 5.4Kpa (0.8PSI) respectively.
+[[http://www.youtube.com/watch?v=hr6x3r8phvE]]
+Testing suggests volume increases by about 33% - 50% at burst (due to stretch). Both tests resulted in a diagonal rips - see pictures.
 {{:projects:balloonburst.jpg|}}{{:projects:2ndburst.jpg?406|}}
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 The balloon material is 31um thick - probably nylon.
-Silver balloons will be been used to minimise any solar gain.
+Silver balloons will be used to minimise any solar gain.
 ===== Theoretical check =====
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-===== Measurement of Ascent rate against free lift ====
-^ Neck Lift (g) ^ Payload (g) ^ Free Lift (g) ^ Ascent Rate (m/sec) ^
-| 0.7 | 0.0 | 0.7 | 0.37 |
-| 4.0 | 0.0 | 4.0 | 0.87 |
-| 4.0 | 2.0 | 2.0 | 0.58 |
-| 10.0 | 6.0 | 4.0 | 0.76 |
-| 10.0 | 8.0 | 2.0 | 0.60 |
-| 10.0 | 9.0 | 1.0 | 0.49 |
-| 19.0 | 18.0 | 1.0 | 0.40 |
-| 31.0 | 27.0 | 4.0 | 0.72 |
-| 31.0 | 29.0 | 2.0 | 0.56 |
-| 31.0 | 30.0 | 1.0 | 0.46 |