AKclimber wrote:Umm, your ASI is in mph and your tape converts it to mph as if the ASI was in knots.

I think he's referring to the paper at the bottom of the photo... I believe the white window in the ASI would be the TAS tape...

Gabe

ebag wrote:

AKclimber wrote:Umm, your ASI is in mph and your tape converts it to mph as if the ASI was in knots.

I think he's referring to the paper at the bottom of the photo... I believe the white window in the ASI would be the TAS tape...

Gabe

Ha!
True that!

CAVU wrote:I worry less about a satellite apocalypse than I do about batteries and electrical gremlins. I subscribe to Foreflight but still buy sectionals for big trips in case the iPad dies while I'm over unfamiliar terrain out of range of the ever-thinning number of VORTACs. I've had iPads shut down from heat and I've also had them down in the single digit percentages of battery with the display turned way down low after a 4 hour flight, even with a recharging brick.

I keep the charts with the E6B in the side pocket. I have two GPSs now, but I've also had enough electrical gremlins over time that I want paper with me when I'm traveling. When it comes to pilotage, knots are easier.


CAVU

MPH for me, my plane is slow enough.

Hell, I still carry one of the old style Flight Guides! Full of personal notes (a good close gas station, or bar or restaurant, here, my own travel guide). And how would I shade my windshield when tied down, without a paper sectional? Not to mention the (thankfully) very occasional use after taking a crap somewhere and then realizing the planes TP supply was gone. OK, I think I did that one time.... There is nothing more embarrassing then to call out a runway heading a few times as you set up a landing, and then realize as you get over the numbers, that due to the earth's wobble (or something like that) the numbers have changed! You may as well just broadcast in the blind, "I have old out of date info and am a dumbass."

I'm not a proponent of integration of instruments with contact flying, but GPS has made the choice of knots vs mph somewhat irrelevant. IMC, decrease in either means pitch up more accurately than artificial horizon. Increase means pitch down. We mostly are radar contact now so don't have to estimate compulsory reporting point to within three minutes.

Extra kinetic energy of staying in low ground effect doesn't care. Zoom reserve doesn't care. Target to target navigation, with two hour potty stops, doesn't care. Apparent rate of closure doesn't care.

courierguy wrote:
MPH for me, my plane is slow enough.

Hell, I still carry one of the old style Flight Guides! Full of personal notes (a good close gas station, or bar or restaurant, here, my own travel guide). And how would I shade my windshield when tied down, without a paper sectional? Not to mention the (thankfully) very occasional use after taking a crap somewhere and then realizing the planes TP supply was gone. OK, I think I did that one time.... There is nothing more embarrassing then to call out a runway heading a few times as you set up a landing, and then realize as you get over the numbers, that due to the earth's wobble (or something like that) the numbers have changed! You may as well just broadcast in the blind, "I have old out of date info and am a dumbass."

LOL! I think I'll pick up a D.C. TAC and keep it in the plane, just in case.

contactflying wrote:I'm not a proponent of integration of instruments with contact flying, but GPS has made the choice of knots vs mph somewhat irrelevant. IMC, decrease in either means pitch up more accurately than artificial horizon. Increase means pitch down. We mostly are radar contact now so don't have to estimate compulsory reporting point to within three minutes.

Extra kinetic energy of staying in low ground effect doesn't care. Zoom reserve doesn't care. Target to target navigation, with two hour potty stops, doesn't care. Apparent rate of closure doesn't care.

I agree, the numbers are irrelevant. I fly Yak's with km/hr and all I care about is where the needle is pointed and what happens when it's there.

They could measure it in potatoes per hour and it wouldn't change anything.

The international standard for aviation distance (set by the FAA at the time) changed from statute miles to nautical miles in 1969. That's good enough reason for me

The purist in me wants to switch to kilometres, but I just can't bring myself to do it

New personal groundspeed record set this afternoon, in knots!

We should all switch to feet per second!! That's the conversion I'm usually doing when off airport. It makes me visualize how hard and how far a bad hit would be.

1.5 x mph is a close approximation.

Aryana wrote:We should all switch to feet per second!! That's the conversion I'm usually doing when off airport. It makes me visualize how hard and how far a bad hit would be.

1.5 x mph is a close approximation.

Meters per second, if we want to join the rest of the planet.

Bagarre wrote:

Aryana wrote:We should all switch to feet per second!! That's the conversion I'm usually doing when off airport. It makes me visualize how hard and how far a bad hit would be.

1.5 x mph is a close approximation.

Meters per second, if we want to join the rest of the planet.

Ummm...pretty sure it's meters per metric second...sorry for making you look ignorant.

Hammer wrote:

Bagarre wrote:

Aryana wrote:We should all switch to feet per second!! That's the conversion I'm usually doing when off airport. It makes me visualize how hard and how far a bad hit would be.

1.5 x mph is a close approximation.

Meters per second, if we want to join the rest of the planet.

Ummm...pretty sure it's meters per metric second...sorry for making you look ignorant.

When converting to metric seconds, do you add or subtract 32? I always mix that up.

Haha!! You guys are great.

I'm a luddite...even all my machining is always done in Imperial measurements, any friends that speak to me in metric are immediately turned away.

So try flying in Australia or NZ to stretch your awareness of units. You have to fly X- FEET above or below cloud but you have to be Y- METERS horizontally from that cloud and your in flight visibility must be Z- KILOMETERS. Your fuel comes in liters and your tire pressure is in kilo pascals!? Don’t even ask what your mileage is because you will get it back in liters/100 Km.

No wonder we quickly resort to universal measurements of “that-looks-about-right”.

YB

dogpilot wrote:The reason we use knots has become somewhat obscure. Before the days of magenta lines on screens we actually had to use paper maps. Sometimes we did this in places that had no actual navaids. So 1 nautical mile was one arc second on the map. So we could dead rekon our position with some idea of where we might be. The nautical mile actually represented something we could relate to, not a wavelength of a hydrogen atom, or three barleycorns, which I never seem to have available when I need it.

So, while MPH might seem marginally useful, when all those satellites go dark from a solar storm or some pissy conflict when the powers decide to switch them off. Be thankful you have knots, you may need it someday...

I know you've been around for a while so I'm quite sure your response was poking a bit of fun. But to expand on what you said, nautical miles are flat out genius for navigating any large distances across the surface of the earth.

One minute of angle (1/60th of a degree) across the earth surface is 1 NM. The border between the US and Canada is the 49th parallel. The 45th parallel passes through Salem Oregon, and marks half way between the equator and the North Pole.

49-45 degrees is 4 degrees of angle, times 60 minutes/degree. Without even picking up a pencil or a paper chart I know it is 240 NM from Salem to the Canadian Border. Show me something cool about a statute mile that matches that. I'll wait right here.

And
Paper charts rock. Try beating the stuffing out of a yellow jacket with an iPad when they come out of the wing root vent.

Boats pioneered all that magic with nautical miles long before aircraft.

aftCG wrote:….Paper charts rock. Try beating the stuffing out of a yellow jacket with an iPad when they come out of the wing root vent.

"More than once" needs to be added to that.

hotrod180 wrote:

aftCG wrote:….Paper charts rock. Try beating the stuffing out of a yellow jacket with an iPad when they come out of the wing root vent.

"More than once" needs to be added to that.

My favorite saying is "You can do anything once!" LOL

When I had to replace the ASI in my 1963 P172D, I asked my IA if I could just do it with a knot-o-meter, since all of my flight planning had to be in knots anyway. He said that I couldn't, because of the certification. But when I had the Quattro installed, I had a choice of IAS in knots or MPH, so I chose knots. That way I have both, MPH on the round dial and knots on the strip.

My dual instruments are handy at times, but frankly it's not a big deal at the airspeeds our little birds fly (even the 180/185/205/206 crowd). At the lower speeds, subtract 10 to the MPH indication. At medium speeds, subtract 15. At higher speeds, subtract 20. Even those who can't "math" well can usually handle that one.

For instance:
65 mph = 56.48 knots = fly 55 knots
115 mph = 99.93 knots = fly 100 knots
150 mph = 130.34 knots = fly 130 knots

Or the reverse:
55 knots = 63.29 mph = fly 65 mph
100 knots = 115.08 mph = fly 115 mph
130 knots = 149.60 mph = fly 150 mph

None of us flies so precisely that a knot or two or mph or two makes a whit of difference.

Cary

whee wrote:A few things got me thinking about this. First was a fairly precise discussion about landing technique in my airplane. Some guys talking in knots with others in mph. It made for a convoluted discussion because you can't just SWAG the conversion when your talking about 30kts or whatever speed puts you on the cusp of a stall.

For precision landings, you should be discussing your airspeed in terms of Angle of Attack (AOA).