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Falcon 1 Staging Recontact - Engine Burp
Likkle vernier rockets pointing upwards?
Brian -- Brian Gaff....Note, this account does not accept Bcc: email. graphics are great, but the blind can't hear them Email: __________________________________________________ __________________________________________________ __________ "Alan Erskine" wrote in message ... "richard schumacher" wrote in message ... Or something as simple as thrust created by gas exhausting from the (new) cooling system. Geez Louise. Does Falcon 1 use anything other than explosive bolts and springs for stage separation? How many more basic errors can they afford to re-discover? Other than the two mentioned, what can be used for stage sep? |
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Falcon 1 Staging Recontact - Engine Burp
Alan Erskine wrote: One word for both Pat and Derek on this: mass. Surely a shaped charge, even a small one, No, it need not be heavy at all, just a thin strip of Det Cord in a housing to focus the blast somewhat. Total weight would probably be in the ten pound range, and since it can be activated from any point on the ring and sever the two stages in a millisecond or two you save a lot of wiring weight as well compared to multiple explosive bolts. would be fairly heavy. Explosive bolts are used regularly on spacecraft, and only fail once in a while. I think the old addage of "Better the devil you know..." In this case it's a known quantity; it's used in solid-fuel missiles to separate stages and vent the casing when thrust termination is desired. The concept goes clean back to WW II when the Germans were going to use cord-type shaped charges to cut apart Wasserfall SAMs that missed their targets to prevent large pieces of them falling onto German cities. The self-destruct system on both liquid and solid-fueled boosters generally use a shaped charge down the length of the rocket to rip it open in case it goes out of control. Pat |
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Falcon 1 Staging Recontact - Engine Burp
Brian Gaff wrote: Likkle vernier rockets pointing upwards? That's been done many a time, up to using upward pointing solid engines to slow down the Saturn V first stage, as the other ones on the interstage push the second stage away from it. Another technique is to ignite the second stage just before the first stage shuts down, and let its thrust carry it away from the first stage as its trust decays In that case you also avoid the need for ullage motors to seat the propellants in the second stage after first stage shut down. The Russians are particularly fond of using that technique, which is why on a lot of their rockets the stages are connected by trusswork so that the exhaust of the stage being started can escape until the stage below it separates. We used the same idea on the Titan II missile. Pat |
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Falcon 1 Staging Recontact - Engine Burp
"Alan Erskine" wrote:
"Pat Flannery" wrote in message hdakotatelephone... You could sever them using a linear shaped charge around the body of the vehicle. One word for both Pat and Derek on this: mass. Surely a shaped charge, even a small one, would be fairly heavy. Explosive bolts and all the associated hardware (bolt retainers and catchers) aren't exactly light either. Shape charges and zip tubes have the advantage of a hell of a lot less wiring. Explosive bolts are used regularly on spacecraft, and only fail once in a while. I think the old addage of "Better the devil you know...". The methods I described are regularly used as well and also only fail once in a while. D. -- Touch-twice life. Eat. Drink. Laugh. http://derekl1963.livejournal.com/ -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL |
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Falcon 1 Staging Recontact - Engine Burp
On Aug 5, 7:09*am, Pat Flannery wrote:
Brian Gaff wrote: Likkle vernier *rockets pointing upwards? That's been done many a time, up to using upward pointing solid engines to slow down the Saturn V first stage, as the other ones on the interstage push the second stage away from it. Another technique is to ignite the second stage just before the first stage shuts down, and let its thrust carry it away from the first stage as its trust decays Wouldn't that damage the first stage, which is supposed to be recovered for re-use? In that case you also avoid the need for ullage motors to seat the propellants in the second stage after first stage shut down. The Russians are particularly fond of using that technique, which is why on a lot of their rockets the stages are connected by trusswork so that the exhaust of the stage being started can escape until the stage below it separates. We used the same idea on the Titan II missile. Pat |
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Falcon 1 Staging Recontact - Engine Burp
"Pat Flannery" wrote in message dakotatelephone... Alan Erskine wrote: Other than the two mentioned, what can be used for stage sep? You could sever them using a linear shaped charge around the body of the vehicle. This would have a advantage over multiple explosive bolts in that the whole thing would fire at once from a single detonation point, improving reliability. The odd stage separation of flight two makes it look like one explosive bolt fired late or not at all, causing the engine bell to hit the interstage structure as the first stage fell away. In the flight 2 report they said the bump was due to using a wrong fuel mixture curve. Too lean at low altitude, so reduced thrust and the staging took place at a much lower altitiude than planned. Which means the staging happened while still under aerodynamic forces...and...while the space craft wasn't aligned with the wind. Pat |
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Falcon 1 Staging Recontact - Engine Burp
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Falcon 1 Staging Recontact - Engine Burp
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Falcon 1 Staging Recontact - Engine Burp
That is what I was thinking, hence my thought on the deceleration motors,
but this is weight taken away from payload, I suppose. Whichever way you look at it, you cannot just assume that the two bodies coasting for a short time will give the desired separation. If you coast too long, in order to protect your first stage from plume damage, you run the risk of sloshing in the upper stage suddenly released from thrust with no continuation within the time you have before it goes float about in the tank. Brian -- Brian Gaff - Note:- In order to reduce spam, any email without 'Brian Gaff' in the display name may be lost. Blind user, so no pictures please! wrote in message ... On Aug 5, 7:09 am, Pat Flannery wrote: Brian Gaff wrote: Likkle vernier rockets pointing upwards? That's been done many a time, up to using upward pointing solid engines to slow down the Saturn V first stage, as the other ones on the interstage push the second stage away from it. Another technique is to ignite the second stage just before the first stage shuts down, and let its thrust carry it away from the first stage as its trust decays Wouldn't that damage the first stage, which is supposed to be recovered for re-use? In that case you also avoid the need for ullage motors to seat the propellants in the second stage after first stage shut down. The Russians are particularly fond of using that technique, which is why on a lot of their rockets the stages are connected by trusswork so that the exhaust of the stage being started can escape until the stage below it separates. We used the same idea on the Titan II missile. Pat |
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