Questions tagged [airspeed]

The speed of an aircraft relative to the air. Among the common conventions for qualifying airspeed are: indicated airspeed ("IAS"), calibrated airspeed ("CAS"), true airspeed ("TAS"), equivalent airspeed ("EAS") and density airspeed.

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4
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1answer
103 views

What is the power curve [closed]

Someone help me understand this thing in a simple way. I understand it helps determine Vx.
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0answers
80 views

What plane has the widest range in speed in which it can operate? [duplicate]

What propellor plane, other than planes with vertical takeoff capability, has the largest gap in speed between its slowest stall speed and its maximum airspeed? I am looking for a plane with a short ...
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1answer
51 views

Constant turn radius with Δ airspeed and bank

Can someone explain how speed impacts rate of turn and and degree of bank required? I'm trying to understand this practice problem but can't get the concept: Say you have 2 vehicles travelling at ...
7
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4answers
347 views

Does “trimmed for current speed” mean that the plane will do whatever to maintain the current airspeed?

If I understand right, when you are trimmed for current speed, let’s say 290 KTAS, does that mean if airspeed increases to 295, the plane will pitch up to slow it back down? And vice versa for the ...
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1answer
38 views

Linking equivalent airspeed with waypoints, altitude, time and speed

Say I want to find out EAS and I'm given a time that a pilot will reach a waypoint that is "X" Nautical Miles away, an altitude & I'm also given a ground speed that is increased by a tailwind. Is ...
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1answer
93 views

What are the equation linking static air temperature with true airspeed & altitude?

If I want to calculate static air temperature (OAT), but I'm only given an altitude and a true airspeed. Is there such an equation that relates these principles together. I've had a look at wikipedia ...
15
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1answer
4k views

Why is a 737 Original speed-restricted below 10 kft with inoperative windscreen heating?

According to this page on the 737's operational limitations, the Original 737s (737-100/-200) are limited to 250 KIAS below 10 kilofeet if the windscreen-heating system is inoperative: Anti-Ice &...
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4answers
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Is any device installed on airplane to measure wind speed relative to the ground, and its direction?

A device or tool which can measure actual wind speed to the ground rather than to the airplane. Also a device which detect the wind direction to the plane. The device I meant is something like this ...
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2answers
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Is it right to extend flaps only in the white arc?

If the cruise speed is >80kts on the downwind leg but I can only extend flaps in the white arc, am I right in saying I need to get to the white arc, even if I'm on - for example - 100kts? For ...
4
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1answer
197 views

Why use Mach number for describing the speed of aircraft?

What does Mach speed mean for describing aircraft speed if the speed of sound changes with temperature?
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1answer
230 views

Why does the F16 HUD give you one number for your speed and the analogue gauge another?

Why does the F16 HUD give you one number for your speed and the analogue gauge another different number?
6
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4answers
2k views

How does speed affect lift?

I understand the lift coefficient shown above. But does lift increase with speed, and how? I understand I can't apply this to the graph as it is a coefficient, but if I had an angle of attack of 10 ...
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2answers
213 views

What is a jet engine's fuel flow at constant IAS?

Here is my assumption: In straight and level flight of a jet turbine engine: One IAS = One drag = One thrust = One fuel flow Therefore, the fuel flow will be approximately the same for a ...
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1answer
81 views

Airspeed Calibration alternate static source, what is this for?

I found a 'Airspeed Calibration Alternate Static Source' Figure in C172R POH. There are three kinds of Figure, 1. Heater off, Vents and Windows Closed 2. Heater On, Vents Open and Windows Closed 3. ...
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0answers
249 views

What is the highest indicated airspeed ever achieved in a traditional aircraft?

It is fairly well known that the SR-71 holds the record for highest speed for a traditional aircraft (not a rocket/able to land and takeoff under its own power). However since the SR-71 flies much ...
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3answers
936 views

What is the difference between TAS and GS? [duplicate]

I'm looking for an explanation of true airspeed and ground speed.
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2answers
198 views

Are there locations/altitudes with minimum speed requirements?

For example, a slower aircraft operating on the North Atlantic Track System would have an operational impact on surrounding/overtaking aircraft as well as potentially increasing ATC workload to ensure ...
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2answers
83 views

How can I calculate the speed gain from using multiple STC modifications together?

Looking at a parts manufacturer website, they list various STC'd modifications for Mooneys with estimated (cruise?) speed gains for each. However, I've heard that those gains are not additive. For ...
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2answers
450 views

What is the fastest unpressurized aircraft?

What is the fastest unpressurized aircraft with oxygen masks that can carry people?
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1answer
108 views

How do I calculate TAS from IAS in this question?

How can I calculate the answer to this EASA PPL ECQB question? An aircraft cruises at altitude 5000 ft on a heading of 180° with an indicated airspeed of 100 kt. The wind vector is 180° with 30 ...
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4answers
2k views

What is the regular stall speed of an F-16 flying in a straight-and-level path?

I want to know what is the minimum speed that an F-16 can fly at without stalling. I have searched the web, but found no exact information answering my question. Most of them say that it depends on ...
4
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1answer
223 views

Does the MU-2 have a crossover airspeed?

Airplanes generally have a crossover airspeed (a minimum airspeed below which directional control of the airplane cannot be maintained in the event of a rudder hardover). This is because, as airspeed ...
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1answer
297 views

How does an airspeed indicator look from the inside?

How does a typical GA airspeed indicator look from the inside and how does it work?
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1answer
185 views

What will be the performance penalties of increasing the wing area of a delta winged aircraft to obtain a lower approach speed?

Delta winged aircraft such as the Dassault Mirage III have an approach speed of 170 knots as specified by the manufacturer. The Mirage F1 was designed to have a lower take off and landing speed than ...
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0answers
291 views

How to find TAS for given CAS, FL and OAT?

Here is another question for my PPL Exam. If anyone can illuminate me with explaining every step to achieve TAS with given parameters, it would be great. Given: Calibrated airspeed (CAS): 155 kt. ...
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1answer
900 views

How to calculate Equivalent Airspeed immediate from Calibrated Airspeed?

I want to calculate each step like IAS -> CAS -> EAS -> TAS as a chain. Each chain step should depend on the previous chain step. IAS is clear. This is function of pressures. With Bernoulli equation, ...
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4answers
473 views

Does diving after a take-off help gaining altitude?

I have often read fictions about aircraft, where a pilot does an action that I cannot explain: During a takeoff with an heavy aircraft (four motors for example), the pilot rolls to the end of the ...
6
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1answer
137 views

Airliner speed when descending through 10,000 feet

How do airliners get to 250 kts when descending through 10,000 feet as required by the FAA? Do you level off at 10,500 feet until speed is less than 250 and then descend further? Must pilots ask ATC ...
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3answers
314 views

Why does an increase of airspeed result in a decrease of angle of attack?

In Chapter 02: Aerodynamics of Flight of Helicopter Flying Handbook, on page 10, it says: Induced flow velocity is increased, resulting in a decrease in AOA. I don't understand how airspeed can ...
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1answer
192 views

How do changes in flight affect L/D max and the speed at which I must travel to maintain it?

I have an plane flying at L/D max and I want to maintain L/D max. Firstly, if this plane burns through a portion of fuel and becomes lighter, how would I have to change the speed to maintain it? My ...
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2answers
160 views

What’s the speed for lowest sink rate on a DA20?

In the DA20, the POH lists for glide speed (flaps up) only one speed giving the best glide angle / furthest distance (73 KIAS). But what about, if I don’t need that much distance to glide (e.g. ...
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2answers
276 views

Why is airspeed different in climbs and descents although the AoA doesn't change?

Here are the background facts: This excercise has the objective to familiarise the student with the slow flight characteristics. The steps are: 1)Establish straight and level, 90% RPM, 15 units ...
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2answers
1k views

What is the effect of altitude on true airspeed?

I know that wind is taken into account when we compute the TAS(true airspeed) and GS(ground speed). However what is the relationship between the TAS and altitude? For example: What is the true ...
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1answer
238 views

How is altitude correlated with true airspeed?

I am trying to understand the BADA 3.0 dataset (specifically I am looking at Performance Summary Tables): E.g. What is not obvious to me is why those tables mention only single TAS for specific FL. ...
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1answer
115 views

Is there an increased concern for stall safety in a 1G steep turn?

Most people know the standard, "At a 60 degree bank, an aircraft experiences 2G's" checkpoint for load-factor on an airplane. I assume that this statement has an underlying, unspoken assumption that ...
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6answers
7k views

Why is indicated airspeed rather than ground speed used during the takeoff roll?

My instructor asked me this question during my lesson and I couldn't come up with any answers. He asked why do I need to look at the indicated airspeed rather than ground speed when in takeoff roll or ...
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2answers
99 views

Pitot tube pressure question

I have this question is the pressure measured in the entry of the pitot tube the same when the plane is flying headwind or turning a 360 degree turn while maintaining the same indicated airspeed?
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2answers
182 views

Why is trim for take off affected to Vmc(Speed maintain control)?

I am studying in Vmc part, but I have hard time to understand that trim for take off is affected to Vmc. How and why does it make Vmc speed increase?
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2answers
3k views

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 ...
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1answer
130 views

Temperature sensor are needed to compute True Airspeed for low speed aircrafts?

I know standard air data computer can produce true air speed with total air pressure, static air pressure, and total air temperature. But for a low speed aircraft <100 knots, do I need to install a ...
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1answer
263 views

Why were the space shuttle’s flight controls only certified for low airspeeds?

Somewhat ironically for a vehicle designed to reach orbital speed, the space shuttle’s flight control system was only certified for airspeeds up to 333 KIAS, and exceeding 470 KIAS (the maximum ...
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2answers
128 views

How should I answer this question about measuring airspeed using dynamic pressure?

I have come across a question in the PPL Principle of Flight material which I can't understand how to answer: Give your opinion on the statement "Measuring dynamic pressure is the way to ...
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2answers
421 views

What are the consequences of touching down at too low of a speed?

The consequences of a high speed touchdown / high vertical speed are very much obvious. However, what will the consequences be of a low speed touchdown? How severe are they (if any)?
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1answer
341 views

Why are the positions of an aircraft's angle-of-attack vanes dependent on airspeed?

According to this answer to an earlier question of mine, the positions of the angle-of-attack sensor vanes on the A330/A340 are dependent not only on AoA, but also on airspeed (and, according to @ymb1'...
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1answer
85 views

What is a simple way to explain why best range airspeed is below normal cruise airspeed? [closed]

Without using complex mathematics, please explain why best range airspeed is less than normal cruise airspeed.
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4answers
993 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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2answers
1k views

Why do aircraft have a crossover airspeed, and why does it increase at higher vertical load factors?

According to the NTSB accident report on the crash of USAir Flight 427, all commercial aircraft have a crossover speed (the speed at which the maximum rolling force from the aircraft’s ailerons and ...
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4answers
247 views

Do airline pilots use speed stability to cope with unreliable airspeed indications? If not, why not?

There have been a couple of airline accidents in which unreliable airspeed indications (or the fear thereof) have played a role: Birgenair Flight 301 in 1996, where one of the pitot tubes was blocked,...
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2answers
1k views

Why do pilots normally fly by CAS rather than TAS?

I think I know the answer to this question, but I want to confirm. Airline pilots normally fly a CAS/Mach profile, which means that above the CAS/Mach transition altitude they fly by Mach, and below ...
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2answers
350 views

What is an accurate expression to calculate IAS as a function of TAS? [duplicate]

Does anyone know a good source for an expression of IAS as a funtion of TAS? I was hoping to find an accurate IAS equation that is only dependent upon TAS, static pressure and static temperature.