VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Main > RV General Discussion/News
Register FAQ Members List Calendar Today's Posts

View Poll Results: Do you use Knots , MPH, or Kilometers To Describe Your Speed?
I use Knots. 279 74.20%
I use MPH 93 24.73%
I use kilometers per hour. 4 1.06%
Voters: 376. You may not vote on this poll

Reply
 
Thread Tools Search this Thread Display Modes
  #21  
Old 01-28-2012, 05:36 PM
DaveLS DaveLS is offline
 
Join Date: Oct 2007
Location: Pensacola, FL & 2R4, Loveland, CO
Posts: 222
Default 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?
__________________
120500
Reply With Quote
  #22  
Old 01-28-2012, 05:42 PM
F1R F1R is offline
 
Join Date: Nov 2010
Location: ____
Posts: 829
Default 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.
Reply With Quote
  #23  
Old 01-28-2012, 05:44 PM
jsharkey's Avatar
jsharkey jsharkey is offline
 
Join Date: Nov 2006
Location: Bennington, Vermont USA
Posts: 1,301
Default

Knots fit well with charts and winds.

Jim Sharkey
RV-6
Reply With Quote
  #24  
Old 01-28-2012, 05:46 PM
sailvi767 sailvi767 is offline
 
Join Date: Sep 2010
Location: Charlotte NC
Posts: 1,167
Default

Quote:
Originally Posted by DaveLS View Post
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
Reply With Quote
  #25  
Old 01-28-2012, 05:47 PM
humptybump humptybump is offline
 
Join Date: Feb 2011
Location: USA
Posts: 3,179
Default

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.
Reply With Quote
  #26  
Old 01-28-2012, 05:47 PM
Vlad's Avatar
Vlad Vlad is online now
 
Join Date: Oct 2008
Location: Utah
Posts: 8,151
Default KMH are faster

Km/h are faster come on guys I can not be alone in the poll. Who else is using metrics?
__________________
Where is N666BK?

Не имей сто рублей, а имей сто друзей.
Reply With Quote
  #27  
Old 01-28-2012, 06:04 PM
Bob Axsom Bob Axsom is offline
 
Join Date: Mar 2005
Posts: 5,685
Default 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.

Last edited by Bob Axsom : 01-29-2012 at 11:41 PM.
Reply With Quote
  #28  
Old 01-28-2012, 06:30 PM
jsharkey's Avatar
jsharkey jsharkey is offline
 
Join Date: Nov 2006
Location: Bennington, Vermont USA
Posts: 1,301
Default

Quote:
Originally Posted by DaveLS View Post
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
Reply With Quote
  #29  
Old 01-28-2012, 06:46 PM
dutchroll dutchroll is offline
 
Join Date: Jun 2010
Location: Sydney, Australia
Posts: 123
Default

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!
Reply With Quote
  #30  
Old 01-28-2012, 07:23 PM
frankh's Avatar
frankh frankh is offline
 
Join Date: Jul 2006
Location: Corvallis Oregon
Posts: 3,547
Default

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..
Reply With Quote
Reply



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 06:47 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.