[USMA:33412] RE: metric usage in launch vehicle

[Philip S Hall]

This example from Boeing does show signs of progress. Note that the first of the specification data is dual but with some preference for feet in that the second page showing the rockets side by side has grid lines in 5, 25 ft intervals, and the final page shows a thrust figure in lb with no metric equivalent.   The second document (nov 2002 update) is however all metric with no non-metric equivalents. Also note the dV (delta-V) in m/s (instead of quoting thrust) and the masses all in metric tonnes.   Phil Hall ----- Original Message ----- From: Terry Simpson To: U.S. Metric Association Sent: Thursday, June 30, 2005 12:50 PM Subject: [USMA:33409] RE: metric usage in launch vehicle >This does not necessarily mean that the rocket was designed in metric units, >although that might be true (?), only that it’s marketed metrically, I suspect for the non-U.S. market.   Delta IV marketing information: http://www.boeing.com/defense-space/space/delta/backgrounders/delta_4_backgrounder.htm   Delta IV specification information has metric dominant (pdf): http://www.boeing.com/defense-space/space/delta/product_card/pc_d4_tech_print.pdf http://www.boeing.com/defense-space/space/delta/docs/Delta_IV_PPG_Update_Nov_2002_change_pages.pdf     Boeing 737 publications now give meters rather than feet for runway lengths. ************************************************** http://www.b737.org.uk/bfos.htm Question “Performance information comes in different units for different 737 variants, shouldn’t the units be standardized since many pilots fly numerous variants in daily operations? <ANSWER> Boeing has traditionally customized performance data to accommodate individual airline operators' units preferences. In general, data in LB and KG is available for almost all airplane-engine combinations. In the distant past, runway lengths from common airport information sources and incidentally, the AFM, were published in FT, which is why metric unit (KG-C) performance data was presented with English unit distances (i.e. FT) in our older books. As more sources of runway data became available in meters, we received increasing operator requests for runway distances to be published in meters. Beginning with the 777, the digital AFM (AFM-DPI) also provided the option to calculate runway distances in meters, and so we began publishing metric-units books in meters rather than feet. This policy was carried over on the newer 737 "next generation" models, which created an inconsistency between runway length units for mixed fleet operators of 737 "classic" and 737 "next generation" airplanes. For mixed fleet operators of airplanes purchased or leased new from Boeing, we will convert the distance units as desired by the operator at no charge. However, under the current economic environment, we cannot guarantee a firm schedule on when this can be completed.” **************************************************