User talk:Bobblewik/units of force

Units of force

BQM-74

Hi again Bobblewik. Two comments on your last edit to this article: 1. Expressing thrust in lb rather than lbf is a very widely used convention in aerospace circles and publications. Since the vast majority of our articles here use lb, it probably makes more sense to follow this convention ourselves. 2. I'm not sure why you changed the metric conversion for 40,000 ft. 40,000 ft is 12,195 m - I could understand rounding to 12,200 m but to 12,000? Cheers --Rlandmann 23:20, 22 Jun 2005 (UTC)

1. I am sure that lots of people would have an opinion on this. Could we discuss the issue in a generic talk page?

2. I am never very comfortable with conversions of altitude. In this case, the article mentioned a range expressed by the manufacturers. This depends on when the rocket motor runs out of fuel. It also depends on the number and extent of direction changes during the flight to follow an uncooperative target. Just like a service ceiling, the boundary from fully functioning to non-functioning is not sharply defined. It is a manufacturer nominal specification which is variable in operation.

I did first round it to 12,200 m because this is usually the precision I use for aircraft. But then I changed my mind because it seemed excessive precision given the very wide operating range to almost ground level. But it was a somewhat arbitrary decision. Feel free to put the value you think is best. Thanks for the questions. Bobblewik  (talk) 08:11, 23 Jun 2005 (UTC)

1. I've asked for comments on the WikiProject Aircraft talk page.

2. I hear your misgivings and agree with them. Indeed, all our performance specifications are subject to the same kinds of qualification - speed, range, climb are all highly variable. We simply have to accept published figures at their face value; indeed, since the figures provided by manufacturers/users of these vehicles are already "somewhat arbitrary", I feel that converting them is really more like a "translation" than anything else. If we were following rules about significant figures, then 40,000 ft would simply be 10,000 m, even further away! --Rlandmann 05:06, 24 Jun 2005 (UTC)