Sender: "Marvin Kaye" <marv@lancaironline.net>
To: lml@lancaironline.net
Date: Sat, 18 Dec 2004 19:57:25 -0500
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From: "Dominic V. Crain" <domcrain@pacific.net.au>
Subject: RE: [LML] Re: MPH?
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In-Reply-To: <list-572505@logan.com>

Thanks Marv for the reply.
The reason I question the terminology is because there are many posts
which refer to MPH.
The recent one which precipitated my question is a classic example.
I am aware that in the US the use of MPH is not all that uncommon, but
it seems important that when referring to performance data, in the
Lancair particularly, the use of knots as conventional terminology
should be clarified.
I have seen many posts where approach and over the fence speeds are
referred to in MPH. If that's what is meant, then the speeds need to be
discounted to knots when making comparisons.
The statement, for example, "I approach at 90 MPH" may well mean 79
knots, unless the contributor actually means 90 knots, but is using the
US convention of terminology, "MPH".
The reason it is important is because inexperienced pilots, or those of
us who have forgotten, need to know that 79 knots does not represent
1.3Vs for the approach.
My aircraft stalls at 64 knots in the approach configuration, and that
means a minimum approach speed of 84 knots, which is 96 MPH.
Given the vast majority of pilots own aircraft which have ASI's
calibrated in knots, I simply hold to the view that if anyone uses MPH
terminology, then they must mean MPH, unless they mean knots, because I
am aware that MPH is a very common American expression, and someone may
well mean knots - but maybe not.
No - I am not being obtuse, but adding a little levity to an important
question.

Regards
Dom