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Flying at 7500ft is fairly handy in my 170 as the indicated mph is pretty close to true knots. |
Knots
Learned to fly in an old 172 with MPH. My instructor told me to use the inner numbers (knots) not the outer ring with the wrong numbers. Since then I have been flying newer 172's with knots. Learned to fly IFR using knots. Started visiting this site and many RV'ers were using the MPH and I am thinking "What the heck".
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"Back in the day" when I bought my used B-55 Baron, it was equipped with a dual scale A/S with knots on the inside ring. I sent the gauge off to the instrument shop where they rescreened the face to show only knots. Come to think of it, the last airplane I had with an MPH A/S was my J3 Cub, which I sold in 1970 :rolleyes:
John Clark ATP, CFI FAAST Team Representative EAA Flight Advisor RV8 N18U "Sunshine" KSBA |
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Heh, I vaguely remember "slugs" from my aerodynamic days at uni. But I don't think I ever did understand why someone came up with such a unit! :)
Hey Vlad, if it's any consolation, I like the metric system and think it makes emminent sense (we converted down under several decades ago, and I speak "both" languages despite my public disdain for mph). But I think the hotchpotch of "standard" aeronautical units is here to stay for a while! ;) |
I've actually never understood why certain manufacturers (certificated or experimental) would mark their systems in mph. The *system*, at least in the U.S., uses knots and nautical miles. I've never heard an ATC specialist ask for or assign any speed in miles per hour.
As some of us know all too well, mixing measurement systems can be a recipe for disaster... At least nautical miles and meters are related to measurements of the earth...1 nm = 1 minute of arc, 1 meter = 1/10,000,000th of the distance from the equator to the pole). Statue miles are essentially arbitrary. :) (BTW, a Roman pace was *two* steps, not one...) (I don't know if it's actually true or not, but my physics prof asserted that if you use the furlongs/fortnight/slug system, virtually all physical constants end up being approximately 1 x 10^some power :) I suspect he just made that up to see if we were listening!) Can you tell I'm up late and bored tonight? LOL! |
The ATC already mixes systems...
Wx is reported in statute miles and therefore the visibility portion of approach minima are published in statute miles... why do we use Feet instead of meters? |
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I think the feet verses meters issues was decided by Pan Am. Much of the worlds conventions on how we fly date back to their early days where there were no standards. Not all nations however use the ICAO standard of feet. Its a pain in the ____ flying in countries that do not with a aircraft set up for feet. Leveling at 11100 meters is one thing but when they ask you your altitude passing and its 26,700 feet by the time my slow brain has done the conversion to meters the number is history not where we are at the moment. Approaches get especially tricky because they often convert from meters standard to local altimeters at very low altitudes like 1200 meters. Add in another conversion since the same countries often use QFE instead of QNH for altimeter settings and things get interesting for the math inept among us. George |
Actually it's Both!
I fly left seat. Ann flies right seat.
Left side of the panel is knots. Right side is mph. She goes faster than I do, but has further to go. We usually get there about the same time. |
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What I use
Personally I use the universal standard of all measurements, the Horse length.
http://en.wikipedia.org/wiki/Horse_length Currently my RV-7 goes 151,840 horse lengths / hour or 2531 horse lengths / sec, commonly referred to in the industry as HLPS. Matter of fact, I was racing a B-55 the other day and on the start, he had me by "the slimmest fraction of a nose." However, by the end of the 2 mile course I had pulled head by at least 25 horse lengths. It was at this point that he noticed a dark substance streaming from my aircraft. He radioed and asked what was coming out of the back end of my trusty steed. To which I replied, "It's horse......" Well, you get the picture. :D |
How far across your EFIS screen does a 6 digit speed tape go? :eek:
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Has anyone notice the performance numbers published by Van's Aircraft for our airplanes is in MPH? Hmmmm?
http://www.vansaircraft.com/public/rv-6per.htm Why would we change what the engineers of our aircraft have determined to be a better unit of measure? ;) |
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From the Reno Air Race web site "Five days of racing action. Six classes of aircraft and speeds exceeding 500 mph." It reads and sounds better than 434.48 knots. But here, clearly the KNOTS have it. Or is it we have KNOTS. :) |
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Knots or MPH, the important thing is get out there and fly. ;) |
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It's all relative
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Airworthiness standards for Normal, Utility, Acrobatic and Commuter Category Airplanes, Title 14, Part 23, specify that distances are to be in nautical miles, and speeds in knots. From a practical point of view, a nautical mile is identical to a minute of latitude, a distance in nautical miles on a chart can easily be measured by using dividers and the latitude scales on the sides of the chart. OK, now I have identified myself as someone who flew long before GPS.
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You mean people actually did aviate prior to GPS? How crude! :)
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ELT Ant locations Certified GPS ant installation requirements Pilot Operating Manuals Adherence to engine RPM and other limits such as Vne Max Gross Weight deviations etc... my .01 |
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Good one Mel. I always thought you were a little slower than your bride. ;) |
I used primer...
...have tricycle gear, a slider canopy and use knots for my airspeed.
There that covers all of them. |
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My airspeed indicator has MPH on the outer (easy to read) scale so I could quickly verify my numbers against Vans. 402 hours later I glance at it occasionally like when in turbulence or while in the pattern. I think most of fly by the seat of our pants after a while anyway. |
Knots or MPH?
Think big. Use Mach.
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Warp Factor?
During bomber competitions, one word indicated a direct hit:
Shack! |
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