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Post by grmcdorman on Jul 16, 2007 12:08:16 GMT -4
(He also just posted another one, about the Columbia disaster - forums.randi.org/showthread.php?p=2771100 if you want to take a look). To this non-engineer, it again seems that he's making inappropriate assumptions). The calculations Greening is describing sounds very similar to the type of thing I've done on many occasions. Although I have no desire to to spend time on this particular problem nor to debate Greening, the coefficients of lift and drag he's using look very suspect to me. I think his L/D ratio is way too high. I'm not surprised. Dr. Greening seems to value his own conclusions in areas outside his expertise too highly. I did respond to his comment about this, but I've basically said I'm not going to pursue it. I don't want to be going off on multiple wild-goose chases; one at a time - and pretty much Apollo related, for that matter - is enough for me.
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Post by Obviousman on Jul 17, 2007 4:45:44 GMT -4
I remember reading that the docked leakage rate was originally specified an <0.1 lb/hr but got revised down to <0.05 lb/hr. I probably have the report I read that from here somewhere, if required. According to the Apollo 11 Lunar Landing Mission Press Kit, the nominal oxygen usage rates were: NOMINAL OXYGEN USAGE RATES
CM METABOLIC RATE 0.08 LB/HR CM LEAKAGE RATE 0.20 LB/HR TUNNEL LEAKAGE 0.10 LB/HR
LM METABOLIC RATE 0.16 LB/HR LM LEAKAGE 0.20 LB/HR FLOW THRU LM CABIN PRESURE RELIEF VALVE 0.06 LB/HR Could it be the tunnel leakage rate that you're remembering? Quite possibly. I'll have a look for the values and quote the proper context.
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Post by Obviousman on Jul 17, 2007 5:08:13 GMT -4
here we go:
LM-A Preliminary Design Review Case 620 dated 21 OCT 68 (available via NTRS, NASA CR-100219?).
Page 2, Para 1 (sub-heading OSCPCS ), sub-para (e):
"Reduce the docked interface leak rate from 0.1 lb/hr to 0.05 lb/hr. MSC feel that NR data supports a lower leak rate."
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Jul 17, 2007 9:13:02 GMT -4
"Reduce the docked interface leak rate from 0.1 lb/hr to 0.05 lb/hr. MSC feel that NR data supports a lower leak rate." "Docked interface leak rate" definitely sounds like the same thing as "tunnel leakage" as referenced in the press kit. It seems then that the press kit is using outdated data. This does not surprise me. I have often found old data being used in the NASA press kits. For instance, there is the following Saturn V News Reference: history.msfc.nasa.gov/saturn_apollo/documents/Introduction.pdfThe specifications on page 5 are what almost always appears in the Apollo press literature even though it is from December 1968 and was outdated by the time of Apollo 9*. It seems NASA had a habit of reusing old data sheets without always taking the care to update it. We have to realize that the press kits were just general information circulated to the news media and can't always be taken as gospel truth. Serious research requires one to did deeper. * For example, note that the 1st stage thrust is given as 7,500,000 lb. After Apollo 8 an uprated F-1 engine was used giving a 1st stage thrust of 7,610,000 lb. Despite the upgrade, you almost always hear the 7,500,000 lb. number incorrectly used by the press.
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Post by JayUtah on Jul 17, 2007 23:43:44 GMT -4
I've found a number of errors in press kits over the years. It doesn't bother me, because I've seen firsthand how such errors can arise innocently and persist. Nor is it a problem for legitimate historians.
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