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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What is the mathematical relationship between mass and speed for constant thrust in level fight?
Imagine that we have a wing with constant thrust in level flight. Then imagine that we add mass to that wing. In order to maintain level flight, I would expect that the angle of attack would need to ...
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What is the difference between VMO and VNE? [closed]
What is classified as a low/ moderate/ severe exceedence? Is it based on a %?
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Why do I keep getting different results to an aircraft's turn radius when I plug variables into different calculators and solve on my own?
I'm trying to solve for an aircraft's turn radius at mach 3.17 (2432 mph) and a bank angle of 19.8; however, after using various online calculators and personally solving the equation, I keep getting ...
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Why does Vx increase with altitude and Vy decrease?
As an airplane climbs, the best angle of climb airspeed (Vx) increases and the best rate of climb airspeed (Vy) decreases.
I can't figure it out, why does it happen?
I Hope someone explains it to me
I ...
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Why was the Me 262's top speed at 6km?
The P-80 had its top speed at sea level, but the Me 262 achieved its top speed at 6km altitude. What were the reasons for this? Was it that the engine was designed for such an altitude to deal with ...
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Does AOA become 0 after the aircraft flies in a particular attitude for sometime as the relative airflow has changed and how does it affect Stall AOA?
As AOA is the angle between relative airflow and Chord Line. Then after you increase the angle of attack and fly at that angle of attack for some amount of time and the relative airflow changes ...
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Determine Vx and Vy from other climbing rate datas
I am developing a small program, working with Microsoft Flight Simulator 2020. For now, I can show my takeoff graph which display the altitude on the y axis and the distance in x axis. I would like to ...
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Sudden Drop in Speed at 1h53 [duplicate]
can someone explain why the speed dropped so sharply and suddenly before going back up at 1h53 here: https://fr.flightaware.com/live/flight/MSR799
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Actual non-axial airflow (sideslip) for a propeller driven aircraft
I am making a propeller model for a two-engine propeller driven aircraft (like a Dornier 228). I have expanded my model to include the non-axial airflow as well. $$ $$
By non axial airflow, I mean ...
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Does CG change airspeed in a descent or glide?
If the CG of an airplane moves forward, would it fly a faster or slower airspeed in a descent?
Usually during a descent or landing, you'd use pitch to change airspeed and power to control descent rate....
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Why the ADS-B out doesn't broadcast the True air speed in its ES message?
The ASTERIX (version 2.1) items of ADS-B GS cat 21 contain True air speed but when we check the Asterix data that we recieved by GS we did not find the True air speed value, why ?
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Is it possible to calculate Calibrated Airspeed from True Airspeed, Temp, and Pressure Altitude? [duplicate]
Looking at a digital E6B, there is a function for calculating CAS that I am trying to recreate and program myself.
Inputs:
Pressure Altitude
Temp in Celcius
True Airspeed
Outputs:
CAS
Mach #
...
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How to Calculate Required True Airspeed to maintain desired ground speed?
Working on programming my own E6B and am stuck trying to calculate the following problem from Sporty's E6B:
Given wind info and desired speed/course, what airspeed/heading should I have in order to ...
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Why do all trend vectors in the G1000 on airplanes indicate the status 6 seconds later? Why 6? Why not 5 or 10?
Why do all trend vectors in the G1000 on airplanes indicate the status 6 seconds later? Why 6? Why not 5 or 10? The fact that the trend vector shows after 6 seconds allows us to turn 3 degrees per ...
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How can TAS be calculated from indicated temperature and Mach number? [duplicate]
Situation
I am working on programming my own E6B while I learn more about aviation, but I have run into some confusion. Two pairs of the equations are very similar except for using true or indicated ...
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Why does an aircraft require less power when it is flying slower than the most efficient speed?
While I understand the derivation of Power required,
I fail to understand why minimum power required corresponds to a velocity that is lower than velocity corresponding to minimum thrust required.
My ...
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Why isnt the structure of the aircraft affected by high true air speeds or high ground speeds?
Let's suppose that in Cruise flight I exceed the VNE in TAS or in ground speed, why isn't the structure of the aircraft affected by the high speeds?
I am sorry for my english, I am not a native ...
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Why does elevator trim hold a given airspeed? [duplicate]
I'm trying to understand a principle described in the book Stick and Rudder by Wolfgang Langewiesche between angle of attack and airspeed in relation to the elevator trim. He states that as angle of ...
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how to calculate wind speed and direction using flight data, at some latitude and longitude? [duplicate]
I have a data file which has the aircraft state details with latitude and longitude recorded for certain radius.
Now, I'm trying to calculate wind direction and wind speed.
Example:
At lat=41 and long ...
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Mathematically calculate Mach number using CAS and PA WITHOUT flight computer
I am just wondering how to calculate the Mach number from CAS and Pressure Altitude WITHOUT the use of a flight calculator.
E.g Given FL300 (30000ft) and 325kt CAS find and Mach number.
I have always ...
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Why use indicated airspeed instead of dynamic pressure [closed]
It uses the difference between total pressure and static pressure, provided by the system, to either mechanically or electronically measure dynamic pressure. The dynamic pressure includes terms for ...
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Is my airspeed calculation code correct?
Not sure if I should ask here, on Drones SE, or on Code Review SE.
Is my Python code for calculating airspeed given ground speed, ground direction, wind speed, and direction from which the wind is ...
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Speed change in IFR flight in class C or D airspace
Can I change speed while flying IFR in class C or D airspace without having a clearance from ATC?
I tried to find it in some documents on EASA website but I did not find anything.
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Should the approach speed and wind be changed below 700ft on an A320?
The FCOM says:
When managed, the speed target is computed by the FMGS and may be
modified by the flight crew through the MCDU. At 700 ft RA, the
current speed target value is memorized by the ...
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Does the reduced aerodynamic damping at higher altitudes affect the Vno (maneuvering speed) of an airplane?
Since reduced aerodynamic damping at higher altitudes reduces the needed control input for maneuvers, is this just about the required force to move the controls or also about the speed of the ...
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Why does true airspeed decrease with altitude?
I was having a discussion with a friend who's going for a record speed over distance attempt. We were discussing which altitude will have the fastest TAS, and I suggested it would be the highest ...
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Air density factor when calculating Airspeed
I am making my own attitude indicator / AHRS, like a Garmin G5. I am using two pressure sensors to measure altitude & airspeed via static /pitot lines.
Now I know the formula for calculating ...
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Does optimum IAS for climb vary with altitude?
I was in an argument about aerodynamics and we eventually derived an equation as follows.
So I'm going by this equation:
$$RoC = \frac{\eta_p P-VD}{W}$$
Where $\eta$ represents propeller efficiency.
...
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How to determine the maximum forward airspeed of a plane in an unaccelerated flight?
What is the equation needed to determine the maximum forward airspeed of a propeller driven plane in an unaccelerated level flight? I need an example with units of measurements.
The engine is rated at ...
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Changing the missile's flight speed
I am interested in the range of velocity changes of missiles. Planes have a minimum speed set equal to the landing speed, helicopters also have a set speed - this is zero, but what about missiles? ...
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What is the speed of anti-ice bleed airflow in helicopter turboshaft engines?
If we consider the most modern turboshaft engines, what will the approximate speed for the bleed airflow when it's routed from the latter stages of the engine and supplied to the areas that require ...
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What about measuring airspeed from control surface forces on the framework?
I watch a lot of these videos that people make about air disasters.
One factor that seems (or hopefully seemed) to crop up is where pilots get hopelessly confused about airspeed, particularly (it ...
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Significance of $\frac{C_L^{3/2}}{C_D}$
I am aware that this value of lift coeff. over drag coeff. occurs when the zero lift drag is 3X the drag due to lift, and that this will correspond to a specific airspeed. What is the significance of ...
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Confused about best range speed and Carson speed
I have read that best lift /drag ratio gives maximum range which makes perfect sense to me.
I have also read Carson speed gives the best fuel consumption. which doesn’t make sense because this would ...
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Does Indicated Stall speed increase with altitude (Coffin Corner)?
It is my understanding that Indicated Stall speed is mostly constant with altitude, the one that increases is True Stall Speed. Given that PFD show speed as IAS, how come the yellow speed range ...
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What is the general mathematical relationship between increasing an airplane's weight and the needed thrust to fly?
I understand that increasing an aircraft's weight without changing any other properties means that its takeoff, stall and cruising speeds all increase since you need to generate additional lift. So ...
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How is a "turning polar" constructed?
To start with something familiar: here's a flight polar. As we learned, the best glide speed is found by starting at the 0,0 point, and drawing a line tangent to the sink rate line. The intersection ...
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How is CAS ans GS affected by instant wind changes at different altitudes
Okay, a theoretical example here which I hope will help me understand the physics better.
Conditions:
Altitude: 50 ft (over sea)
GS: 300 knts
CAS: 300 ktns
Wind: 0
If I now get a 10 knts head wind (...
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How to compute the airspeed change based on the Altitude change
The plot shows that: when I fly with fixed MACH, the true air speed decreases when the altitude increase; when I fly with fixed CAS, the true airspeed increases when altitude increase. So how could I ...
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Airspeed change in wind shear
The instrument questions I’m studying say that a decreasing tailwind will increase airspeed. I can’t wrap my head around why this would be the case.
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TAS from POH or e6b
I always calculated my TAS at any cruise altitude by
Using my planned cruise (pressure) altitude, temperature
Plug desired CAS, PA, temperature into e6b and get TAS
But I've also seen people get TAS ...
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Please describe ram pressure in simple terms [duplicate]
Please someone describe the following sentence in simple words:
The Airspeed Indicator is calibrated for 'standard' sea level density, so it will only read TAS if the density of the air through which ...
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Modern method to verify speed of a homebuilt aircraft
Summary: In 2001, airspeed of homebuilt aircraft was calculated by flying in a ⊔-shape and using trigonometry to subtract wind effects. Now that we have portable computers, is there a more modern ...
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What is the green arrow on the 777's airspeed tape? Does it exist on other types as well?
Image source: fsnews.eu
I found this green arrow on the primary flight display (PFD) of a 777. What does it show? I'm assuming it's for showing acceleration and deceleration but I am not too sure. Is ...
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Calculating airspeed by flying in a U shape: Horseshoe Heading Technique
I saw some equation in a log recently and I believe it went something as follows:
$v_1$ : flying North, $\ \ v_2$ : flying West, $\ \ v_3$ : flying South.
$$
\text{TAS} = \frac 1 2 \sqrt{v_1^2+v_2^2+...
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Strange airspeed indicator in the Douglas X-3 Stiletto
The cockpit of the Douglas X-3 Stiletto has a rather weird looking airspeed indicator. (The leftmost instrument in the top row.) Two concentric circular scales, the outer one goes from 0 to 20, the ...
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Why airflow travels faster on upper wings?
I have been looking for solutions and come up with two popular explanations:
Conservation of mass / Continuity
For a positive-cambered wing, the streamlines would be compressed/converged at the ...
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Power calculation of propeller
This is probably a very simple question, but I have been really struggling and need your help.
I have simulated a propeller with these parameters on Ansys:
Thrust: 2000 N
Angular Velocity: 314 rad/s
...
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Do pitot tubes account for reduced pressure at altitude?
Do pitot tubes account for reduced pressure at altitude?
Does indicated airspeed reduce with altitude? If so, how much?
Is it different for small planes vs big commercial airliners?
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How are IAS/CAS and TAS used in flight?
Could you please explain to me one moment in relation to IAS and TAS. In all books I read I see that the IAS is highlighted as a reference for stall, take-off, landing and other performance items. So, ...
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