rakall wrote:Arun_S wrote:
This DRDO's Large Size Solid Booster
when used as a single stage ABM will be approximately:
Mass: 2,700 Kg (2.5tonne booster mass + 200Kg interceptor including terminal cross thrusters)
Length: 9-10 meter
Powered Flight time:38 sec
Final velocity: Mach 11.5 (3.5Km/sec)
Minimum intercept altitude: 45Km (that is how long the booster burns before it can release the kill vehicle)
A 2-stage ABM that has 500Kg second stage will be approximately:
Mass: 2,700 Kg (2.5tonne booster + 500Kg second stage + 200Kg interceptor including terminal cross thrusters)
Length: 10.5-11.5 meter
Powered Flight time:58 sec
Final velocity: Mach 15(4.5Km/sec)
Minimum intercept altitude: 70Km (that is how long the booster burns before it can release the kill vehicle)
These numbers correspond to firing at an angle such that terminal velocity is at 45 degree elevation (this also allow reader to roughly estimate the ground imprint when payload becomes active ).
Bheri bheri different from any other missile in world.
Arun -- are you not beeing very cute/cheeky in your first sentence.. "this booster when used as".. so the numbers are (only) for the case if this booster is used as ABM. But you are not revealig if it "is used" or "if you think it is used"..
1. The flight time as 1stage ABM is 38sec from the motor specs per DRDO release.. However per some reports the interception time is 110/117 seconds.. i think it is not too comfortable for the interceptor to be un-powered for so long (~70secs).. and with 200Kg total mass it may have very less powered flight of its own..
given that prithvi liq-fuelled Prithvi has a flight time of 300sec to reach a 150km target.. we can assume about the same or more for a solid-fuelled Prithvi (going longer range)6m long 1m dia motor..
total powered flight of it can be as low as 38sec? is that enough? (assuming 0.8m dia motor burn time will also be same as 1m dia counterpart)
2. please look at the 2-stage ABM mass calculations.. they dont add up..
You missed adding the 2nd stage mass to the total
You are right Rakall on Mass calculation.
On powered flight and non-powered one..it depends upon the situation. And for the terminal phase interceptor 70 secs unpowered flight is high.
To add..there are two ranges reported normally. One if max. range. And, other is max. range of flight. Max. range is range covered by powered flight. and max. range of flight is one including the non-powered flight time.
With that information, if you see the spec of Arrow-2, max range is 70km and max. range of flight is 90 km. With this information, if we did gross comparison, 70s non-powered flight is too high.
There is one more angle too, to show there is discrepancy in the data provided above.
For stage 1. Max. velocity is given as 3.5 km/sec. Initial velocity is 0. If we assume, uniform acceleration. Then average velocity is 1.75 km/sec. With 38 sec. duration its range is 66.5 km.
For stage 2. Intial velocity is 3.5 km/sec(due to first stage terminal velocity) and final velocity is given as 4.5 km/sec. So average velocity is 4km/sec(assuming uniform acceleration). For a duration of 58 secs, range convered is 232 km.
Now we add the first stage range + second stage, Then total range of AXO is 298.5 km.
Even if we consider, drift and change in g, and other data, this is too high compared to what is reported in the media the range as 100km.
I cautioned him on using the data which appeared some 6 yrs ago. Anyway its all boils to individual opinion.