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--- projects:splat [2020/11/14 10:28] – [Super Pressure Musings] rocketboy
+++ projects:splat [2023/02/19 12:10] (current) – [Project aim] rocketboy
@@ Line 6: / Line 6: @@
 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:float1f.xls|float1f}} 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}}
+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 48: / 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.
+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% at burst (due to stretch). Both tests resulted in a diagonal rips - see pictures.
+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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-===== 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 |