Author Topic: Knots on Airspeed indicator - when started? (Read 1017 times)

artik · « **Reply #15 on:** October 12, 2004, 01:02:31 PM »

You right,

Once meter was defined as 1/N part of Grinwich Meridian...

However since then it was changed to be measured in wavelegthes.....

So all this is interesting..........
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HoHun · « **Reply #16 on:** October 12, 2004, 02:29:03 PM »

Hi Artik,

>Once meter was defined as 1/N part of Grinwich Meridian...

Definitely not! :-)

It was defined as fraction of the PARIS zero meridian :-)

I don't know how long the Paris meridian was actually used for navigation, but it was still indicated (along with the "international meridian") on the IGN maps of the 1980s!

By the way, the IGN operated some B-17s for surveying purposes, keeping them in flying condition for ages until selling them off to collectors.

Here's one of them that's still in flying condition:

Regards,

Henning (HoHun)

Urchin · « **Reply #17 on:** October 12, 2004, 02:49:35 PM »

Lol, they kept the guns on them? That just seems.. strange.

HoHun · « **Reply #18 on:** October 12, 2004, 02:59:16 PM »

Hi Urchin,

>Lol, they kept the guns on them? That just seems.. strange.

Of course they did. They also loaded bombs to attack the Greenwich meridian should it ever cross the French border.

Regards,

Henning (HoHun)

Broes · « **Reply #19 on:** October 12, 2004, 03:32:04 PM »

How fast is a knot compared to furlongs/fortnight?

HoHun · « **Reply #20 on:** October 12, 2004, 05:29:07 PM »

Hi Broes,

>How fast is a knot compared to furlongs/fortnight?

Easy in SI:

1 knot = 1,852 km/h = 1852/3600 m/s = 0,514 m/s

1 furlong/fortnight = 1609,34 km * 1/8 / (14 * 24 * 3600 s) = 0,166 mm/s

=>

1 knot / (furlong/fortnight) = 3093

Regards,

Henning (HoHun)

MiloMorai · « **Reply #21 on:** October 12, 2004, 05:35:41 PM »

Quote

Originally posted by Broes
How fast is a knot compared to furlongs/fortnight?

A fortnight is 14 days.

Angus · « **Reply #22 on:** October 12, 2004, 06:52:54 PM »

A fortnight usually contains the chance for 2 pubcrawl weekends

ubadger · « **Reply #23 on:** October 13, 2004, 01:54:35 AM »

Hice thread !

Still no one knows when US Navy planes started to use knots on airspeed indicators or did they use any other unit at all?

Casca · « **Reply #24 on:** October 14, 2004, 01:45:51 PM »

A knot is a measure of speed, not distance, ie. 1 nautical mile per hour.

A nautical mile is equal to one minute of latitude. A minute of latitude is always the same distance. The distance of a minute of longitude varies at each latitude due to the fact that the meridians converge at the poles.