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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.aviation
Subject: drag
Message-ID: <6311@utzoo.UUCP>
Date: Tue, 21-Jan-86 17:02:17 EST
Article-I.D.: utzoo.6311
Posted: Tue Jan 21 17:02:17 1986
Date-Received: Tue, 21-Jan-86 17:02:17 EST
References: <196@hropus.UUCP> <968@terak.UUCP> <865@masscomp.UUCP>, <185@aplvax.UUCP>
Organization: U of Toronto Zoology
Lines: 17

> ...  A lot of research is presently being done to...
> find a way to decrease the effects of the shock waves...

It's worth remembering that if you are sneaky enough, some of those effects
can be beneficial.  The XB-70A, in particular, was shaped so that at cruising
speed (Mach 3!) the shockwaves from various parts of its body and wing
combined to pack air under the wing, producing a tremendous improvement in
lift/drag ratio.  I believe the XB-70A wing had the highest L/D ratio ever
seen in a supersonic wing, given optimum conditions.  Which was why the
XB-70A had a range of 6000+ miles at Mach 3, while most other supersonic
aircraft have negligible range at anything much beyond Mach 1.

Alas, the XB-70A was kind of expensive, and the optimization for a single
speed doesn't adapt well to things like orbital vehicles.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry