06-28-2013, 08:12 AM
First Indian RV's never fly at a speed determined by terminal velocity (its a sitting duck for even simple ABM systems). So any projection/estimation using that approach is incorrect.
I earlier just put some calcuation (quoted below) based on the assumptions that the RV flew a ballistic trajectory.
[quote name='Arun_S' date='23 June 2013 - 12:03 PM' timestamp='1371968715' post='116688']
Atmospheric pressure changes quite sharply during re-entry into denser part of altitude. Almost always RV's don't reach terminal velocity. Simulations give proper answers.
A1 for maximum range enters at near 45 degree inclination. Thus not knowing the cross angle of camera shot can be overcome by only requiring change in vertical altitude.
Some information to consider for A1 with 1,000 Kg warhead at full range:
Now that can give an idea of the payload yield because there is an optimum air-burst altitude for a given payload.
[/quote]
However A1 RV are known to be maneuvering kind (MaRV), and they can fly level (or sloped / gliding) where their vertical decent speed can be vastly slower compared to decend rate for a ballistic re-entry. Thus it is impossible to estimate HOB with that one video (too little information). The only conclusion that can be made with certainty was the RV sparked very very close to the boxed space and the camera was stationary and looking at a tiney space (defined by the kill box),, meaning the RV showed up where it was expected (aimed at).
I earlier just put some calcuation (quoted below) based on the assumptions that the RV flew a ballistic trajectory.
[quote name='Arun_S' date='23 June 2013 - 12:03 PM' timestamp='1371968715' post='116688']
Atmospheric pressure changes quite sharply during re-entry into denser part of altitude. Almost always RV's don't reach terminal velocity. Simulations give proper answers.
A1 for maximum range enters at near 45 degree inclination. Thus not knowing the cross angle of camera shot can be overcome by only requiring change in vertical altitude.
Some information to consider for A1 with 1,000 Kg warhead at full range:
- Air speed : 1,750 m/sec (at 3 Km altitude)
- Angle: 45 deg (thus vertical component of velocity is 1.24km/sec)
- Time from air burst altitude to half the air-burst altitude: ~ 1 second. (during this time the velocity did not noticeably change; to be expected due to disfigured payload and change of Cd there of.
- The camera distance was >> air bust altitude, so the sine ~ tan
- Thus the air-burst was at about 2.5 Km altitude (The error depends on time measurement. If one gets finer time stamp measurement teh estimate will be more accurate )
Now that can give an idea of the payload yield because there is an optimum air-burst altitude for a given payload.
[/quote]
However A1 RV are known to be maneuvering kind (MaRV), and they can fly level (or sloped / gliding) where their vertical decent speed can be vastly slower compared to decend rate for a ballistic re-entry. Thus it is impossible to estimate HOB with that one video (too little information). The only conclusion that can be made with certainty was the RV sparked very very close to the boxed space and the camera was stationary and looking at a tiney space (defined by the kill box),, meaning the RV showed up where it was expected (aimed at).