10/23 Raptor Video

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BJC

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I would say that metric system is mush easy to work with, but I can fly in both systems - it's easy to convert them:
1mph = 1.6 kph
1knot = 1.8 kph
1000 feet = about 300 meters(1/3)
And if you can remember - 1 foot = about 0.3 meters and minute have 60 seconds, then you can figure your vertical/or wind speed too ;)
Converting doesn’t make sense for me. Work within one system, and don’t worry about the others. Time is the same in all systems.


BJC
 

Chilton

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As far as I know Russia uses metric, EASA still uses feet for altitude, with altimeter settings in hectopascals, speed in knots or Mach. Weight in kilograms and runway length in meters but distances are in Nautical miles.
 

BBerson

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Most airplanes and gliders manufactured in EU (and destined for the EU market) have airspeed indicators in kmh, altitude in m and vertical speed in m/sec.
The vario in my German motor glider is kts/second I think. But when the needle is on 4 that is roughly 400 fpm so no problem. (that's three systems)
 

Jerry Lytle

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I believe the metric system is the only system approved by a United States law. It is not a violation of the law to use miles, feet and inches but these were never the law of the land.
 

BBerson

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Knots per second? That would be a unit of acceleration, not velocity.

I've seen plenty of varios in knots and plenty in meters per second. One knot is about 0.5 m/sec.
Right. One knot is 1.6878 feet per second. I should have said one knot is 101.2 feet per minute.

So if the knot vario needle is on the 5 knot that is 506 feet per minute.
And the USA vario needle is on the 5 that is 500 feet per per minute. Close enough.
 

Aesquire

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I believe the metric system is the only system approved by a United States law. It is not a violation of the law to use miles, feet and inches but these were never the law of the land.
IIRC the U.S. went Metric in 1895. Few bothered to change. When your tools and tooling are all paid for, buying all new tools wasn't attractive.

It's a cascade effect. If you don't want to do extra math, you need measuring tools, reference gauges, ( Jo blocks! ) and every machine tool with a lead screw is obsolete. Total rebuild on every lathe, mill, etc. Since that was a bit before microprocessors, it's all dials and handles with dials, and all of them are Imperial.

Some tools like Shapers, ( I think I'm the last Generation to actually use one, and that was just in school ) and purely manual ( no precision carriages ) drills, mills, etc. convert over without a fuss to Metric.

The philosophical differences, "everything divisible by the fingers of a typical guy" and "Length of everything is based on a decent guess to the diameter of a Planet we happen to live on" Are logical, if a bit lazy. Metric lacks the romance of "a dead King's Thumb, or a certain number of barleycorns" & "Roman Infantry Marching standards" & "how much ale can you carry?" "Lift in a glass?" & "biggest barrel you want to roll onto a ship, up a wooden ramp with battens"....
 

Marc Zeitlin

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...but it does prove it didn't flutter at that speed and flew almost 3 hours.
It only proves it didn't flutter if he did flutter tests by exciting the control system with stick raps. Which, of course, he did not, because you don't do flutter testing that low. edit: <Well, that and because he's not actually testing anything...>. And with the extreme compliance in the roll system, stick raps won't tell you jack sh1t anyway. Pitch and MAYBE yaw could be flutter tested on that plane.
 
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TFF

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Standard as it should be. You have to know both here. Rare to convert. Just uses what is in front of you.
 

BBerson

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It only proves it didn't flutter if he did flutter tests by exciting the control system with stick raps. Which, of course, he did not, because you don't do flutter testing that low. edit: <Well, that and because he's not actually testing anything...>. And with the extreme compliance in the roll system, stick raps won't tell you jack sh1t anyway. Pitch and MAYBE yaw could be flutter tested on that plane.
I didn't suggest he was doing any flutter testing. Only that it didn't spontaneous flutter at that new speed as far as we know. Might have vibrated or something but we don't know details anymore without the video reports.
Each speed increase increment has some technical value.
Is there any public disclosure of flutter testing in the EA-B plans or kit industry?
 

Turd Ferguson

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It's a cascade effect. If you don't want to do extra math, you need measuring tools, reference gauges, ( Jo blocks! ) and every machine tool with a lead screw is obsolete. Total rebuild on every lathe, mill, etc. Since that was a bit before microprocessors, it's all dials and handles with dials, and all of them are Imperial.

Nah, they solved that decades ago. I have an Italian lathe, with English dials, that cuts English and metric threads despite having a lead screw with English threads.

Manual machines with dual reading dials have been around a long time. Most have English threads on the feeding screw so the English dial is "keyed" to the feed screw while the metric dial is "geared" to the feed screw. They make kits to to convert machine tool dials to dual scales.

Going back and forth is forever unavoidable. For example, a company specs a piston at 81.5 mm and then the instructions tell you the proper clearance in the cylinder bore is .006" -.008" (wth? lol)

english_mm.jpg
 

Turd Ferguson

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The US law was passed in 1975. The Metric Conversion Act is an Act of Congress that U.S. President Gerald Ford signed into law on December 23, 1975.
And since that day the US has slowly moved toward the metric system, inch by inch.

We will always have AN-6 bolts so don't throw your fractional spanners away ! ! !
 
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