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From: mccolm@ucla-cs.UUCP
Newsgroups: net.games.frp
Subject: Re: net.games.frp.physics - flying with a tail wind
Message-ID: <5610@ucla-cs.ARPA>
Date: Tue, 21-May-85 20:26:22 EDT
Article-I.D.: ucla-cs.5610
Posted: Tue May 21 20:26:22 1985
Date-Received: Sun, 26-May-85 21:50:14 EDT
References: <868@mhuxt.UUCP>
Reply-To: mccolm@ucla-cs.UUCP (Eric McColm)
Organization: UCLA Computer Science Department
Lines: 56
Keywords: movement rates before taxes
Summary: 

(This line has come face-to-face with the Universal Oneness.  Urk!)
   ...there's something here about two people on a flying carpet...
>one member being towed behind them with a rope and a ring of levitation, two
>members with the druidical form changing abilities, and two members riding
>two hippogriffs.

Sounds like a moving tourist attraction.

>    I decided to have my druid character use a Control Winds spell to give us
>a 30 mph tail wind.  Working through the conversions, I found that 30 mph
>works out to be 68"/rnd; adding in our flying speed, we should have been
>moving at around 90"/rnd, about 5 times the speed we could have gone on
>horseback.  Unfortunately, the DM ruled that wind speed and flying speeds are
>not additive.  I guess there may be some justification for this in the case
>of the carpet, since it doesn't use aerodynamics to fly.

What?  68"/rnd (outdoors) = 3*680 ft/min = 34 ft/sec = 21 mph (about).
Remember, 2mph = 3'/sec, or very close.  So human running speed is about
9'/sec (in armor), or 180 yds/min, or 18"/rnd (outdoors).  180"/turn?  Yep.

Keep in mind that movement speeds in AD&D are at *mapping* speed, which is
a very inventive way to express movement rates for animal-intelligence
monsters. <insert deranged-looking face here>

A flying object, like an animal, has a groundspeed G=A+nW, where A=airspeed,
W=wind velocity, and 0<=n<=1 is the efficiency of the object in using the
wind to accentuate velocity (or avoid wind effects; W can be negative).
For magic objects, a warning:  if you decide magic carpets are unaffected
by wind (n=0), watch out, because they'll fly into the teeth of a gale at
full speed.

This is, of course, a simplification, but it's fast and easy, except for
when you try to deal with crosswinds.  (Can you say Trigonometry?  Good.)

Levitating people are effectively weightless, but not massless, and they
still have wind resistance.  So they'll slow you down if you tow them.
And in a force 14 gale, they'd better have heard of New England Life...

>And what is the average flying speed of a laden hippogriff?  <English or
>African? ... Aaaaah!>

Depends.  Where's the nearest candy shop?  (Creepin' Chocoholics, Batman!)

>Jeff Sonntag
>ihnp4!mhuxt!js2j
--fini--

Eric McColm
UCLA (oo' - kluh) Funny Farm for the Criminally Harmless
UUCP:  ...!{ihnp4,trwspp,cepu,ucbvax,sdcrdcf}!ucla-cs!mccolm
ARPA:  (still) mccolm@UCLA-CS.ARPA  (someday) mccolm@LOCUS.UCLA.EDU

Q1:  "The world is round.  With all else, it's up to us."
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