Altimeter settings: QNH versus QFE

I also know the classical arguments like "a nautical mile
equals a minute of latitude", but how often do you fly true north or
south?)

Airplane pilots like to look at the length of a course line, compare it
to the minutes latitude and know exactly the distance without the use of
any other tools. I understand that there are other tools. I was raised
as a Dutch man and brought up with the metric system - and prefer it.
But, to me nautical miles make sense, YMMV.

On another topic, why have horizontal speed in km/h and vertical speed
in meters/sec? To me, this is odd. If the units were the same, you could
simply divide one into the other and get the L/D - again, YMMV.

Tony V.

"Tony Verhulst" wrote in message
...
I also know the classical arguments like "a nautical mile
equals a minute of latitude", but how often do you fly true north or
south?)

Airplane pilots like to look at the length of a course line, compare it
to the minutes latitude and know exactly the distance without the use of
any other tools. I understand that there are other tools. I was raised
as a Dutch man and brought up with the metric system - and prefer it.
But, to me nautical miles make sense, YMMV.

On another topic, why have horizontal speed in km/h and vertical speed
in meters/sec? To me, this is odd. If the units were the same, you could
simply divide one into the other and get the L/D - again, YMMV.

Tony V.

Knots, MPH, KPH, meters/sec are just numbers. Just read the POH and fly the
numbers.

However, I have a beef with metric altimeters. The large hand reads 1000
meters per rev. An imperial units altimeter reads 1000 feet per rev. 1000
meters = 3281 feet so the metric altimeter is less than 1/3 as sensitive as
the one based on feet. To me, that seems inadequate.

I like to see the altimeter hand move with small changes in altitude.
That's confirmation that all is well in the instrument panel. I've seen
haywire varios insistently reading up while the altimeter was winding down.
I'm not sure I would have spotted that as quickly with a metric altimeter.

I suppose there is no reason that a metric altimeter could not be more
sensitive. With today's digital technology, 100 meters per rev should be
possible. I've never seen one that sensitive.

Bill Daniels

Bill Daniels wrote:

I like to see the altimeter hand move with small changes in altitude.
That's confirmation that all is well in the instrument panel. I've seen
haywire varios insistently reading up while the altimeter was winding down.
I'm not sure I would have spotted that as quickly with a metric altimeter.

I suppose there is no reason that a metric altimeter could not be more
sensitive. With today's digital technology, 100 meters per rev should be
possible. I've never seen one that sensitive.

Actually, even yesterday's digital technology already provides very
sensitive altimeters in our varios, GPS units, or flight computers.
These are digital readouts, of course, not hands, but I find myself
looking at my Cambridge 302 altimeter reading much more than the
mechanical one. You can use it in feet or meters, and have plenty of
sensitivity.

The next mechanical altimeter I buy will likely be an INsensitive unit,
like one of the 0-10,000' or 0-20,000 single hand units for less than $150.


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Eric Greenwell
Washington State
USA

In article ,
"Bill Daniels" wrote:

However, I have a beef with metric altimeters. The large hand reads 1000
meters per rev. An imperial units altimeter reads 1000 feet per rev. 1000
meters = 3281 feet so the metric altimeter is less than 1/3 as sensitive as
the one based on feet. To me, that seems inadequate.

Some gliders I have flown have altimeters marked in feet, but 3000 ft
per revolution rather than 1000.

Presumably it's possible to design a single unit for either metric or
imperial use and tweak the calibration by the 10% difference.

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Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------