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From: conor@inmos.co.uk (Conor O'Neill)
Newsgroups: sci.space.shuttle,sci.space
Subject: Exhaust velocity
Message-ID: <2639@ganymede.inmos.co.uk>
Date: 23 Oct 89 13:20:44 GMT
References: <538.252A3A3B@mamab.FIDONET.ORG> <34577@srcsip.UUCP> <126311@sun.Eng.Sun.COM> <1307@accuvax.nwu.edu> <15596@netnews.upenn.edu> <1321@accuvax.nwu.edu> <1989Oct18.174154.23242@utzoo.uucp>
Reply-To: conor@inmos.co.uk (Conor O'Neill)
Organization: INMOS Limited, Bristol, UK.
Lines: 15

In article <1989Oct18.174154.23242@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>In general, correct.  For one thing, it's easier to build solid motors
>in large sizes (i.e. high thrusts).  For another, the average molecular 
>weight of the exhaust is higher, which is bad for getting maximum velocity
>but good for getting maximum thrust.


I've seen this said before (many times) but never with a simple explanation.
My school physics seemed to imply that it is exhaust momentum which matters,
not simply velocity nor molecular weight. Could someone please elaborate.

-- 
Conor O'Neill, Software Group, INMOS Ltd., UK.
UK: conor@inmos.co.uk		US: conor@inmos.com
"It's state-of-the-art" "But it doesn't work!" "That is the state-of-the-art".