# Questions tagged [units]

For questions regarding units of measurement used in aviation

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### In what units is the Thrust-to-Weight ratio expressed?

is it correct to say the units for T/W is s^2/m? This is what I did: T/W= s/ft * ftlb/s * s^2/lbft
808 views

### On what basis is the weight unit of the FQIS selected by airlines of various countries?

On what basis is the weight unit of the FQIS (Fuel Quantity Indicating System) selected by airlines of various countries? Does it depend on the local country for using imperial or metric units?
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1 vote
85 views

### What units should use for velocity prediction equations?

I'm not an expert aviation but I'm designing my own RC Plane and I wanted to estimate the maximum velocity using equations (15-20) from this paper. Honestly, I am not quite sure on the units to use ...
11k views

### How could "aggressor" pilots fly foreign aircraft without speaking the language?

Context I watched a couple documentaries recently and found one where they were mentioning the training of American forces against Mi-24 that were captured and brought back to the US to test fly them....
1k views

### How much does the horizontal stabilizer on a 737 move for one unit of trim?

Inspired by this question, what exactly is the meaning of a stab trim unit? Is it exactly one degree of stabilizer movement? The 737 NG FCOMv2 (9.20.9 Flight Controls - System Description) only lists ...
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### What is a jet (unit) shown in Windows 10 calculator? [closed]

From Windows 10's calculator: What is a "jet" (physical unit)? And why does it equal 480 knots or 888,88 km/h, if a jetliner's cruising speed is around 950 km/s? Or why does it equal 0.73 M, if a ...
• 4,162
1 vote
3k views

### What is the official unit of airplane/aviation speed?

Some units I read/found are commonly used in aviation: mach, knot (nautical mile per hour), mile per hour (mph), kilometer per hour (km/h or kph). "Official" meaning like the units used by the flight ...
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430 views

### How to compare two SFCs, one in thrust, the other in power (both turbofans)?

I want to compare some recent turbofan engines in terms of fuel efficiency, particularly the PW535A and FJ44-4. I found the SFC for the PW535A to be 0.44 lb/h/lbf. I couldn't find anything on the ...
1 vote
946 views

### What is the unit for ground speed reported by ADS-B?

Strangely enough, I'm having trouble finding the unit reported by ADS-B on the Internet. Many sites simply refer to it as "ground speed". Is it measured in KPH?
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### What is the distance unit on a navigation display?

I want to learn what is the distance unit on a navigation display. I pointed the distance marks with red circles on the navigation display. What are these 10, 15 etc. values' unit? Are they ...
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### Does the US military use metric system?

Does the US military use the metric system for aviation? For example, does it use: feet or meters for altitude? nautical miles or kilometers for distance? knots or km/h for speed? inHg or hPa for ...
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331 views

### What units are used by western airliners? [duplicate]

Many different units can be used to designate the same things. Degrees Celsius va Fahrenheit Altitude in feets or meters, ... Sometime different units measure the same thing but have different ...
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### Does the Cessna POH state the fuel consumption in Imperial or US Gallons?

I'm planning a trip in a Cessna 182T and was calculating fuel requirements and started wondering. I have always assumed that fuel consumption is in US Gallons (or 3.785 litres) but I can't find a ...
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### How do pilots manage metric altitude?

A minority of the world, specifically Russia and China, uses the metric system in aviation. ATC will tell the pilots to "climb to 900 meters height". How do pilots of international flights manage ...
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### Still using knots, nautical miles, inches of Hg. Is that impossible to switch to SI units? [duplicate]

Why doesn't the aviation industry use SI units?. I believe only a few countries use meters and other SI units in air transportation, including India and China (please correct if wrong). Using kts ...
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