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Sunday, February 01, 2015

CALCULATIONS

I knocked up an Excel spreadsheet to calculate the angles, locations etc. The problem is a tricky A level Mathematics-type question.

Assuming:
1. steady wind speed of 20 Km/h;
2. steady wind blowing from the east;
3. direct distance between location of photographer and proposed launch site of 7 Km;
4. time between launch and photograph of 2.5 minutes (30s from launch to strike, then another 2 minutes for photographer to take the photos) i.e. very generous time for photographer to get prepared;
5. angle between line of sight to launch site and wind direction was 45 degrees.

then the white plume would be directly over the east end of the village called Chervonyi Zhovten (Google Maps) and thus surely very visible to the inhabitants of that village and surrounding towns and villages.

However, a steady wind 20 Km/h is quite a strong wind given that the gusts were 13 Km/h maximum, i.e. a relatively calm day.

So assuming a steady wind of 12 Km/h speed, and the photo taken at 1 minute after launch (30s from launch to strike, then another 30s for the photographer to take the photos) then the plume would still be hanging over the field containing the proposed launch site and would be visible over the three ropeways in the photos.

If we assume a steady 15 Km/h wind and photo taken 2 minutes after launch then the plume would barely have left the field containing the proposed launch site.

I am not convinced, unless:
1. the wind speed about 50 m above ground level was a steady 20 Km/h at least;
and/or
2. the photographer took much longer than 2 minutes to take the photograph after hearing explosions.

I also think the white plume looks like it is a lot closer to the photographer than the launch site, suggesting a wind direction of SE or ESE, but records all state E or ENE.




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