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Old 01-21-13, 07:24 PM   #6
NeonSamurai
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Join Date: Jan 2002
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Mission 4: Rocket tests series KV-2
Objective: Multi stage liquid fueled rocket testing.

Launch 1 mission parameters: KV-2 vertical launch and vertical ascent to maximum altitude. KV-2 is a two stage rocket

Payload: various scientific instruments contained inside the nose cone of stage 2.

Another day dawns and the new KV-2 rocket stands ready on the launchpad


Stage 1 engine ignition is a go and KV-2 Lifts off into the air


As the rocket reaches an altitude of 13km fuel runs out in stage 1


At t:+ 00:00:55 the stage two successfully separates, but the stage 2 engine refuses to ignite despite multiple attempts.


Stage two falls back to Kerbin and crashes.

Looking around for some sort of evidence of kerbalnauts messing with the launch, the scientists cannot find any reason for the launch to have failed.

Debriefing, Launch 1:
The cause for the engine failure was undetermined.

5 further launches were attempted with this rocket, all resulting in failure during the second stage, In 3 of the launches, stage two exploded on ignition, in one launch the stage 2 engine pulsed to life and exploded a fraction of a second later, the last launch failed to ignite on separation but did ignite, stutter fired for 2 seconds then cut out as it plunged nose down back to Kerbin.

Several different theories were proposed, such as their being a flaw with the engine design, or their was not enough insulating cheese in the engine system (or any cheese for that matter), or that it had to do with the wrong Koodoo chants being given before launch. One particularly dimwitted scientist suggested that the problem may have to do with the loss of gravitational forces on the rocket during engine shutdown, creating a micro gravity situation, which cause the liquid fuels to float away from the motor inlets and entering a slushy state of gas, liquid, and solid. These "ullage" gasses were what was causing the failures with the second stage. He proposed adding micro thrusters to stage two, which would fire just before main engine ignition, to push the liquid fuel back against the inlets.

Of course he was taunted mercilessly by the other scientists for being a total knee biter, until he demonstrated he was right by showing the other scientists telemetry data from the stage two fuel tank which showed fluctuations in the fuel. Grudgingly the other scientists decided to fit ullage motors to the second stage of launch 7, along with a redesigned ignition system, The rocket is re-designated as KV-2A


Launch 7 mission parameters: KV-2A vertical launch and vertical ascent to maximum altitude.

Payload: various scientific instruments contained inside the nose cone of stage 2.


Main engine for stage 1 is a go, and as with the previous 6 launches, it takes to the air without problem


As before stage 1 runs out of fuel and the scientists prepare to go to stage two


Everyone holds their breath as the ullage motors fire with stage separation


2 seconds later stage 2's engine roars to life, all readings nominal. A cheer rings through mission control!


As the fuel runs out, scientists look at the calculated apogee for stage and are stunned
The craft manages to reach a staggering 2175km altitude, even thought it has 3/4 the fuel capacity of the KV-1

Signal is lost from KV-2A 20 minutes before reentry due to the power running out. Radar shows it crashing just off the coast


Debriefing, Launch 7:
Launch 7 is a stunning success. Kerbal scientists can't believe the altitude achieved even though KV-1 has 1.33333 times the fuel of KV-2A and KV-2A is functionally heavier after the fuel weight difference is calculated in, due to carrying two rocket engines (KV-1 weighs 6.81 metric tones (with fuel), and KV-2A weighs 6.26 metric tones), yet KV-2A hit an altitude almost 10 times as high as KV-1.

The scientist who found and came up with the solution to the ullage problem suggested that this was due to the effect of having a multi-stage craft, as it is able to shed excess weight during flight, and use a more efficient upper stage rocket engine designed for high altitiude, vastly increasing it's total potential DeltaV. But the other scientists felt the result was because of the new Koodoo priestess they found for this flight. The brilliant young scientist was later chased off by a roving mob of torch and pitchfork wielding scientists, who had decided that the one thing they hated more than those blasted kerbalnauts, was a smartypants.


Debriefing Mission 4:
This mission demonstrated the need for ullage motors during flight for multi stage rockets, it also demonstrated how much more efficient staged rocket designs are. On another note the Van Kerman radation belt theory was shown to be valid thanks to the extreme altitude KV-2A reached
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