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Knots or MPH?? That Is The Question

Do you use Knots , MPH, or Kilometers To Describe Your Speed?

  • I use Knots.

    Votes: 279 74.2%
  • I use MPH

    Votes: 93 24.7%
  • I use kilometers per hour.

    Votes: 4 1.1%

  • Total voters
    376
I have always used MPH, no real reason, the airspeed was calibrated that way, and it made more sense to me somehow.
 
Knots. A holdover from IFR training and I've stayed with that. Except, there's a guy on the field with a Lancair 320 - so for him, I speak in Km/H.

Dan
 
Km/h

I brag in kilometers per hour because the numbers are impressive but system requires knots that's what I use :)
 
That would be mighty embarrassing, while on an IFR flight, to report your speed in MPH when prompted by ATC. You might get asked if your riding a tricycle or something :).
 
Knots are for ships. No one cares how fast a ship goes. ;) No one (the general public) knows how fast a knot is so you have to sit there and explain it every time. This is a waste of time, spent only attempting to make the pilot feel superior over the person asking. (Right Marty!??;))

Think of how many time you have had to ask; "Knots or MPH" at OSH or any other time you are talking speed. Folks! We are talking about wasting time at OSH! There should be a law against that!

MPH is for airplanes. Most pilots uses statue miles to a destination when traveling they usually don't use nautical miles. There is that term again "nautical".... is for ships! Why confuse the issue?

I hereby declare MPH the official measure of speed for RV's. ;)
 
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Yeah, what Larry said.

Soon as they start marking maps with knots to show distance from place to place, then it will make sense to use them.
 
Yeah, what Larry said.

Soon as they start marking maps with knots to show distance from place to place, then it will make sense to use them.

Sort of like an aviation chart with nautical miles shown between stations? I guess it makes sense to use knots then.
 
Knots for speed because that how the ASI reads and what ATC uses to tell me what the wind is doing, feet for altitude, litres for fuel (we're in Australia), millibars for atmospheric pressure, psi for tire (tyre) pressure, miles for distance (should be kilometres), deg centigrade for air temperature, deg fahrenheit for the engine, etc ....

Aviation must win the prize for the most bizarre set of units of measurement ever devised :confused:
 
Yeah, what Larry said.

Soon as they start marking maps with knots to show distance from place to place, then it will make sense to use them.

Seriously? I did not know that! ;) When was the last time anyone used a paper map? Do they still make them? :rolleyes:
 
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Hybrid knots and MPH. I always refer to groundspeed in knots, and airspeed in MPH. I learned to fly in Cessnas which had MPH on their ASIs. My Cherokee that I flew for 10 years was also in MPH. Every taildragger I flew (C140, Cub, Supercub, Citabria) and learned tailwheel flying, was also in MPH. The RV-4 that I really learned how to fly RVs in, was also in MPH. My friend's RV-8 that I currently fly has a Dynon D-100, which makes it easy to change back and forth, is generally always left in MPH because the owner prefers it that way too. I've just gotten accustomed to learning all the airspeed numbers in MPH and old habits are hard to break. The RV-6 I'm looking to buy has steam gauges, and its ASI is in knots, so I guess I'll just have to learn a new set of numbers if I do end up buying that plane.
 
The ATC system uses knots. That is good enough for me. It makes things nice and simple when they assign you a speed or ask your speed.

George
 
The military use knots. The airlines use knots. ATC uses knots. Team RV uses knots.

You can use furlongs per fortnight in your own airplane. Use knots only if you want to fit in.
 
The military use knots. The airlines use knots. ATC uses knots. Team RV uses knots.

You can use furlongs per fortnight in your own airplane. Use knots only if you want to fit in.

And, only the vain use MPH, cause they want to see a higher speed. lol!! :):):)
 
Virtually every single reference to speed and distance in every aeronautical document, chart, sectional, AIM, FAR, not to mention every controller uses nautical miles.

It's the unit for the system. Anything else is just for bragging rights.
 
I use mph when bragging about the speed of my 6 to my nonaviator friends just so I don't have to explain the difference between mph and knots to them but use knots when with my aviator friends and talking to atc. And even they ask me mph or knots? May be easier to use mach. "I was cruising along at .23,..." sounds good.
 
Mph is easier

A mile is based on 1,000 Roman paces.

A nautical mile is one minute of latitude.

Charts use latitude and longitude, and thus have distance scales all over them.

Sectionals are charts.

But if you want to use miles all you haft to do is measure the distance against the latitude scale to determine the number of minutes multiply by 6,080 (apx) and divide by 5,280.

Who uses Mach?
 
Knots

The earth is surveyed in Deg, min and sec. 1 Minute of latitude is 1 NM, anywhere.

The cosine of your Lat position is equal to the decimal value of one Minute of Longitude at your current Lat.

It's the foundation of all naval and aviation navigation.:)
 
A mile is based on 1,000 Roman paces.


Who uses Mach?

True story, happened to a friend of mine instructing in a T2. The T2 was slow but could fly very high. I don't even think it had a mach meter. Flying a new student on his first cross country. Near El Paso at 39000 feet they are asked to say their Mach. The student quickly replied that he was Maching the 090 radial at 78 miles. The follow on laughter on the control freq my friend found quite embarrassing!!! A discussion with the student on the ground about the difference between Mark and Mach took place.

George
 
I use knots for airplanes - even a Stearman (which makes for some really sad numbers). The only time I use MPH is when talking to my mom because she can understand MPH.
 
KMH are faster

Km/h are faster come on guys I can not be alone in the poll. Who else is using metrics?
 
I use kts and mph depending on the situation

Saying speed in kts to a driver gives them a unit of measure that means nothing except in their mind the airplane is slower than it really is.

When talking to pilots and ATC I use kts.

When reporting race results I use both because you don't know the preference of the reader.

I guess I can't vote.

Bob Axsom

I voted KM/HR because it doesn't mean anything and I was tired of Vlad sitting there all alone.
 
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A mile is based on 1,000 Roman paces.

A nautical mile is one minute of latitude.

Charts use latitude and longitude, and thus have distance scales all over them.

Sectionals are charts.

But if you want to use miles all you haft to do is measure the distance against the latitude scale to determine the number of minutes multiply by 6,080 (apx) and divide by 5,280.

Who uses Mach?

They must have had long legs :)
 
Knots. A statute mile per hour means nothing to me.

Aside from the minor fact it's impossible to get a plane certified here with a mph airspeed indicator, 1 knot = 1 nautical mile per hour = 1 minute of latitude per hour = graduations which are marked on aeronautical charts the world over = internationally accepted aviation standard for airspeed/tas/groundspeed.

If you can read lat/long on an aeronautical chart, then you know what a "nautical mile" is by default. If you can't read lat/long on an aeronautical chart, why are you flying a plane? I've never understood the morbid fascination with continuing to measure speed in statute miles per hour in an aircraft. ;)

Mike
Down Under
No offence intended! :D
 
RV's are fast enough to use Knots and get respectable numbers..well OK, not the RV12...:)

The serious answer is one talks to ATC continuosly while flying IFR, speed comes up quite often (either cus there is a Cessna put put in front of you or a jet behind you) and your better off using the same language.

As an engineer that is fluent in both metric and Imperial units, I have to say the metric system is by far the best.

You have no idea how hard it is for an English guy to admit that anything invented in France is better..:)
 
Knots are for ships. No one cares how fast a ship goes. ;) No one (the general public) knows how fast a knot is so you have to sit there and explain it every time.

MPH is for airplanes. Most pilots uses statue miles to a destination when traveling they usually don't use nautical miles. There is that term again "nautical".... is for ships! Why confuse the issue?

I hereby declare MPH the official measure of speed for RV's. ;)

Larry, That is the most ridiculous thing I have heard in a long, long time.
 
No!! Not what Larry said.... knots are what have always been used in my world and thats the way our charts are made. I don't ever feel the need to explain anything to non-aviation types who don't understand the difference - it doesn't matter. Just say "it's about the same", because as far as they are concerned it is. Just say that that is the way we do it in aviation. One nautical mile is equal to one minute of arc at any lattitude and equal to one minute of arc of longitude at the equator. One degree is 60 minutes or 60NM of lattitude anywhere or 60NM at the equator. It actually means something when you reference an aeronautical chart - or your gps lat/long. Statute miles is for lesser earthbound beings. Nascar likes to reference mph because it's good for advertising. When ATC asks you or assigns you a speed, they are talking knots. When you shoot an instrument approach, you are dealing with nautical miles and knots on timed portions of the approach. You can get a plastic 'ruler' that reads both from Sporty's to break it down if you're using a sectional, but why make it so difficult? Pilots use knots Drivers use mph.... if 60 mph is your min safe speed over the fence, then use 60K instead - you'll be safer!!
 
I'm old-fashioned. I recall that the first airplanes used MPH, so that I what I have my instruments set to use.

Greg
 
And yet ...

The metric system is the standard in the united States as determined by Congress L-o-o-o-o-o-o-o-g ago. They have spent a fortune to make us convert to it for many decades and yet we still commonly use the English system. Strange isn't it. The only thing it has achieved is force me to buy more wrenches.

Bob Axsom
 
Use Knots. It is the standard. MPH is unprofesional, and braging

I use Knots...but today I needed to do some bragging. So before work I took a short flight over the ice fisherman at the Annual Perch Derby. Zipped by them at 150agl(offset 350') doing 205MPH just to show them what 200mph looks like. At the end I pulled into a ~3000fpm climb.

Life is good at 178kts, but 205mph makes a better fishing story.
 
MPH for me. In training I used knots and Nautical miles. Once training was completed, I bought an old airplane, 69' Cherokee. Only had MPH. Sold that and bought another old airplane, 65' Mooney. Again, only MPH. 500 hours in planes using MPH, so I'm still using MPH. IFR is not in my interest, so no need to worry. :)
 
The average 6 foot tall male has about a 3 foot stride. In the example of a mile equal to a thousand Roman paces, their stride had to be 5' 3" long!! And YES.... that would require some very tall legs.

BTW......... How did the 201 Mooney get it's name?
 
I learned to fly in beat up, slow, old planes marked in mph. The only other plane I owned was old and slow and marked in mph. I associate ASI's marked in mph with old and slow. It's a source of pride having a plane marked in knots that easily gets into 3 digits! Knots for me:D I also find it makes more sense with the charts and ATC.

Jeremy
 
Most pilots uses statue miles to a destination when traveling they usually don't use nautical miles.

EVERYONE we fly with uses nautical miles ... because that is what is on all the charts.
Where would one get charts with statue miles? AAA:eek:
 
You have no idea how hard it is for an English guy to admit that anything invented in France is better..:)

I do love this forum!
 
So Larry, just how many buckets of popcorn have you enjoyed since stirring this pot up, eh! ;)

And "nobody cares about how fast a ship goes"?...I dunno, how fast the carrier was going made a fair bit of difference in the "quality" of the air behind it (more natural wind = less burble), so we cared how fast it was going! (We also cared how fast it was going when it was headed into port! :cool:)

Hey Mike, all those Class B, C, D, Mode C, etc rings and things on charts (and yes, in GPSs too)...what kinda miles are those in...hmmmm ;)

So there are a lotta knots out there...the only ones I don't like are the ones that get in my headset cord...pesky dern things! :rolleyes:

MPH sounds good to U.S. race fans (500 MPH Unlimiteds and 400 MPH Sports does sound pretty cool, ya gotta admit)...and it sounds good to U.S. airline passengers (they'll get there faster...and happier...at 500-600 MPH...yessir!). If you're quick, or do it 6-10 times a day (outbound and inbound...AMHIK), you can convert KTS to MPH on the fly, just like C to F temps, which we also have to do, since C is on the paperwork, but is still a mystery to most folks here (and as Bob Ax said...we were going to be converted by 1975!

If you really want to brag, state top speed in MPH, and stall speed in KTS, then you win on both ends! Don't screw it up though! ;)

And have you guys forgotten? Girls like knotty boys...so what are ya thinkin'!?! :D

Cheers,
Bob
 
RV's are fast enough to use Knots and get respectable numbers..well OK, not the RV12...:)

The serious answer is one talks to ATC continuosly while flying IFR, speed comes up quite often (either cus there is a Cessna put put in front of you or a jet behind you) and your better off using the same language.

As an engineer that is fluent in both metric and Imperial units, I have to say the metric system is by far the best.

You have no idea how hard it is for an English guy to admit that anything invented in France is better..:)

The American (Imperial?) system is an engineering pain and a mistake waiting to happen for anything involving mass because it uses the same units for mass and weight or force.

Jim Sharkey
 
So Larry, just how many buckets of popcorn have you enjoyed since stirring this pot up, eh! ;)

And "nobody cares about how fast a ship goes"?...I dunno, how fast the carrier was going made a fair bit of difference in the "quality" of the air behind it (more natural wind = less burble), so we cared how fast it was going! (We also cared how fast it was going when it was headed into port! :cool:)

Hey Mike, all those Class B, C, D, Mode C, etc rings and things on charts (and yes, in GPSs too)...what kinda miles are those in...hmmmm ;)

So there are a lotta knots out there...the only ones I don't like are the ones that get in my headset cord...pesky dern things! :rolleyes:

MPH sounds good to U.S. race fans (500 MPH Unlimiteds and 400 MPH Sports does sound pretty cool, ya gotta admit)...and it sounds good to U.S. airline passengers (they'll get there faster...and happier...at 500-600 MPH...yessir!). If you're quick, or do it 6-10 times a day (outbound and inbound...AMHIK), you can convert KTS to MPH on the fly, just like C to F temps, which we also have to do, since C is on the paperwork, but is still a mystery to most folks here (and as Bob Ax said...we were going to be converted by 1975!

If you really want to brag, state top speed in MPH, and stall speed in KTS, then you win on both ends! Don't screw it up though! ;)

And have you guys forgotten? Girls like knotty boys...so what are ya thinkin'!?! :D

Cheers,
Bob


It's January, cold, windy, a little "cabin fever" setting in. This is what happens when there is no build in the shop.

" No one cares how fast a ship goes!" Did I really say that? :eek:. I was in the Navy, yes we cared. :D

We have been debating this for some time in another group and it spilled over into this one as an after thought. Just having some fun.
 
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I am just having some fun. It's January, cold, windy, a little "cabin fever" setting in. " No one cares how fast a ship goes!" Did I really say that? :eek:


Your fun was taken seriously by the majority of VAFers. How come nobody uses metrics? I heard one favoring Mach but the unit was not in the poll. :D
 
Hey, we decided this issue years ago, right here on VAF. Everyone was happy with the Mock System.

100 mph = Mock 1....cocktail party bragging rights for RV-12 owners.

200 mph = Mock 2....routine for the rest of us, although -9 owners really should fix their static system leak.

300 mph = Mock 3....used by a small group of Rocketeers, or the airport liar.
 
A question...

All the reasons for using knots are valid. However, I use MPH because that is what every plane I have piloted since I started flying in 1968 has the ASI in MPH. I was instructed in MPH. I don't fly IFR, and the guys I fly with use MPH.

Does anyone know why, if knots is the standard for aviation (charts, ATC, ect.), it seems virtually all civilian aircraft made in the last 50 years have ASI's in MPH? It seems like the manufacturers should have used knots, but they didn't. Or would that be an option when the plane was manufactured and the buyers selected MPH?
 
Klik

Your fun was taken seriously by the majority of VAFers. How come nobody uses metrics? I heard one favoring Mach but the unit was not in the poll. :D

Vlad! Everything on VAF is taken seriously...Larry saw a Saturday Night Live opportunity and took it. Proud of you Larry! Of course everyone is right because the airplane doesn't care and soon they will all be flying without pilots anyway (we just get in the way). And yes, the metric system is used in the states by the US Army...just ask any grunt what a klik is...and always has been.

Pete
 
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