ApolloHoax.net
Apollo Discussions => The Reality of Apollo => Topic started by: Obviousman on February 11, 2017, 10:15:55 PM
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This is about the Chinese space programme, so apologies if I am in the wrong section of the board (it seemed appropriate here).
I was watching the launch of a manned Long March 2F booster (Shenzhou 7). From what I saw, I thought that - different from the Saturn and STS - it did not seem to have any hold-down clamps, and launched immediately upon booster ignition. I didn't see any thrust build up before release.
Is this correct?
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The Long March uses hypergolic propellants, so ignition might look a little different from rockets burning either kerosene or solid fuels. Sure that's not it?
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If you have a look at this video, there is a slight delay; perhaps I just didn't notice it in the clip I originally saw?
The delay doen't seem as long in this one:
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This rocket seems rather precariously balanced.
(https://dl.dropboxusercontent.com/u/98915197/ApolloHoax/Shenzou10.jpg)
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There should be some supports that retract just before liftoff otherwise it wouldn't stand long with high wind conditions.
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The Long March uses hypergolic propellants, so ignition might look a little different from rockets burning either kerosene or solid fuels. Sure that's not it?
LM-1 through to LM-4 have ICMB antecedents (hence their propellants) and you would expect a reasonably energetic departure from the pad.
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The Long March uses hypergolic propellants, so ignition might look a little different from rockets burning either kerosene or solid fuels. Sure that's not it?
Is this why the exhaust looks more "pinkish" and "see-through" rather that the bright orange/yellow we are used to seeing with LOX/Kerosene?
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The Long March uses hypergolic propellants, so ignition might look a little different from rockets burning either kerosene or solid fuels. Sure that's not it?
Is this why the exhaust looks more "pinkish" and "see-through" rather that the bright orange/yellow we are used to seeing with LOX/Kerosene?
Yes. More recent rockets use different propellants - LM-5 LH-LOX and RP1-LOX, LM-6 RP1-LOX, LM-7 RP1-LOX.
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Is this why the exhaust looks more "pinkish" and "see-through" rather that the bright orange/yellow we are used to seeing with LOX/Kerosene?
Yes, hypergolic propellants produce a characteristically faint plume even at sea level. See also videos of Gemini/Titan II launches, and of the early (pre-SRB) models of ESA's Ariane. You'll often see a tinge of red or orange from unreacted N2O4 during ignition.
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If you have a look at this video, there is a slight delay; perhaps I just didn't notice it in the clip I originally saw?
I see a hold-down delay in both clips: short, but definite. The engines probably reach "mainstage" (steady state operation) as soon as the transient ignition clouds disappear from under their nozzles, but there's still a definite pause before liftoff.
You want the hold-down to be long enough to allow all engines to reach operating pressure, but not so long that you just waste propellant.
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Many thanks!