Questions tagged [aircraft-performance]

Aircraft performance covers areas such as the amount of runway required to takeoff or land and how fast an airplane can climb or descend.

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3answers
197 views

Are there aircraft that fly without fuel or electricity?

I was browsing through Wikipedia when I saw this: An electric aircraft is an aircraft powered by electric motors. Electricity may be supplied by a variety of methods including batteries, ground ...
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1answer
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How to reduce the noise of the supersonic passage(bang)?

as you know the transonic phase is often associate with the bang. The principal cons of the transonic phase is the noise,it's why there is not supersonic passenger aircraft( cause the end of the ...
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Question related to efficiency [closed]

A 4 x T56 Allison Turboprop equipped aircraft holding at a lower than optimum altitude. If you shut down one or more engines you could run the remaining engines at a higher, more efficient RPM ...
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1answer
100 views

Would it be beneficial to limit AOA in fly by wire type a/c like F16 jet in dogfights? [closed]

Would limiting the angle of attack to a maximum of 13 degrees by the fly by wire system help pilot gain advantage over his/her enemy during aerial one to one combat? Using such limits would reduce the ...
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2answers
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Why does camouflage make some planes fly slower?

Why does camouflage decrease some airplanes' speed? I have noticed that some planes fly slower with camouflage than without it. For example, when the RAF applied camo on the P-51 Mustang, they noticed ...
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First Boeing 757-200 N757A 'Catfish' was modified with a Canard foreplane. How did it behave?

The aircraft had these changes made around 2006 to act as an F-22 Avionics test bed. One would expect that the fore plane changed many performances of machine, including take off and landing attitude ...
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How to choose airfoil for High Subsonic small UAV?

I am trying to make a concept for a small UAV. The UAV shall be flying at Mach=0.75 , shortly 0.9 For this, I am looking for an adequate airfoil, which allows me, to avoid Mach=1 on the airfoil. From ...
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1answer
84 views

What does performance speed refers to? Aircraft performance in general

For example C172R specifications: Cruise speed:122 knots What does this mean? Maximum achievable Indicated airspeed At specific conditions? Another example - rate of climb: 721 ft/min For what ...
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1answer
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What is the climb-out angle of a twinjet upon one engine failure scenario?

Take a typical 737-800 or A320 at MTOW how much difference in take off angle does a 1 engine out failure scenario make, compared with a normal 6-8 degree take off angle with full engines.
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1answer
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Does the phrase “.78/280/250” have a standard meaning to an airline pilot, in the context of a long descent?

Does the phrase ".78/280/250" have a standard meaning to an airline pilot, in the context of a long descent? Specific context-- the table in this answer-- Is the descent performance of the PMDG 737-...
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1answer
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What is an airliner's “green dot speed”, and how does it vary with weight, and why?

A related question told us, quoting from an Airbus performance manual, Green dot speed (minimum gradient) is a function of weight. Comments under the question stated that the "green dot speed" ...
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Why does an airliner have a shallow descent when heavier, opposite to gliders with ballast?

Gliders utilize water ballast to, among other things, descend faster: But sometimes you need to get down fast: This is when water ballast is added. In airliners however, the heavier the plane, the ...
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Why does increasing a glider's weight using water ballast improve its speed and performance? [duplicate]

I was studying gliders and how they fly. There is a point that's not clear to me: why does using water ballast improve the performance/speed of a glider? If I understand correctly, my glider jumps ...
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1answer
54 views

Which Velocity is used to measure Dynamic Pressure?

Suppose an airplane is flying in windy conditions. Now, for the calculation of the dynamic pressure should I use the relative velocity or the absolute velocity as the free stream airspeed?
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1answer
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Why does the Pratt & Whitney 747 have an extra engine on the right side but not left side? [duplicate]

What’s the purpose of this design, and why only on one side?
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Flight management System(FMS) related to Performance Managment

What are the recommends criteria and requirements for a Flight Management System (FMS) for transport aircraft related to Performance Database or Performance Management
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2answers
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Transonic Airfoil with high critical mach number

does anyone know, how I can find a transonic airfoil (high subsonic, Ma=0.88) with a high critical mach number? I know that if I know c,0,min = minimal pressure coefficient of the airfoil, then I can ...
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1answer
101 views

Is there a graph that shows the thrust required for a given airspeed? [duplicate]

I would like to see the graphical relationship between thrust required and airspeed for a typical general aviation aircraft, e.g. C-150 or C172 series.
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Carpet Plots for Aircraft Sizing

Generally, Carpet Plots are constructed to find out an optimal design which will satisfy all the performance needs and is least in weight & cost. I want to know how to construct a carpet plot? I ...
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5answers
336 views

Can you fly 2000 miles on an engine that costs less than $500k? If so, what type of engine?

Ok so Im exploring ways to bring cargo and medical supplies to various rural cities in say Africa without relying on ground infrastructure. Just short and cheap runways spread around the continent. It ...
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1answer
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What's the relation between TAS and Mach in tropopause?

I understand that TAS decreases with altitude with constant Mach number in troposphere, however I'm not sure what happens in tropospause, as the temperature is constant, however the density is still ...
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2answers
159 views

Are there any examples of sustained human-powered flight above ground effect?

Every video of human-powered flight has the plane or helicopter so close to the ground that it benefits from ground-effect. Is there any exception to this rule, i.e. a still-air-level-ground human ...
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3answers
159 views

What is physics explanation for minimum sink rate airspeed?

I did some research on Minimum Sink Rate, and saw much information defining it, (such as it is the speed at which the aircraft will remain in the air for the longest time, etc.) and how it is ...
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2answers
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Do helicopter rotors have anti-ice systems like propellers and wings?

Icing disrupts the aerodynamic qualities of wings and props, is there a similar danger with helicopter rotors? Are there de-icing systems to prevent this?
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1answer
525 views

What happens if an aircraft tries to land at MTOW (if greater than MLW)? [duplicate]

Here's a scenario: Just after Take-Off, there's an emergency on-board and pilot wants to land immediately. But, the weight of the plane wouldn't have decreased by large margins (usually 0.02*MTOW). ...
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Cruise Mach Number less or more than Critical Mach Number

Do commercial airplanes cruise at Mach number higher than the critical Mach number? And what is the critical Mach number of airplanes like B777 or A330?
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1answer
79 views

During which phase of the mission profile, the airplane fastest?

In a mission profile, there are various phases such as Climb, Cruise, and Descent (excluding other phases). My question is during which of these phases, the Mach number of the airplane is highest? Is ...
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1answer
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How can I identify the aircraft’s phase of flight in this picture?

It’s me again, can anyone explain how to know the aircraft’s phase from this picture? Is it cruising or descending if so why its flaps up?
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1answer
307 views

Why is 51,000 ft a common service ceiling for business jets?

According to this article on aerospace-technology.com, many of the larger business jets seem to have a service ceiling of 51,000 feet. Other sources verify this trend. What is the reason for this, if ...
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What are the most powerful airplanes that ever flew?

This question What are the least powerful airplanes that ever flew? made me wonder what the most powerful manned airplanes are that ever flew. There are two sensible categories, I suppose: Most ...
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3answers
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Could an airliner be as efficient lower and slower?

Could an airliner ever be as efficient at 15 or so meters using ground effect as it is at 50,000 km even if it has to go slower and be shaped differently?
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5answers
358 views

How efficient would an airliner be if it did not have to carry its own fuel?

Hypothetically, if all the fuel was supplied externally or pulled from the atmosphere to where the plane had never to carry any fuel on board, how much more efficient would an airliner be? The plane ...
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1answer
51 views

Can I use any reference area for lift and drag coefficient?

I know that for rockets they often use the circular cross-section S_reference for the drag prediction: drag = rho/2 v^2 * c_D * S_reference For aircrafts they use the chord length of a wing as ...
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2answers
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What is the method to find the resonance frequency of a PowerFlow exhaust?

I asked a related question about PowerFlow Exhaust systems, which produced another question for me: How do they go about finding the resonance frequency so they know how long to make the exhaust pipe? ...
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4answers
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Would a 50 mph aircraft holding a ground pattern in a 20 mph cross wind risk stalling by abruptly rolling away from a crosswind?

This is another play on the "down wind turn myth". We all know a plane flying in a "uniformly moving airmass" is not affected by wind direction and speed. But a plane following a ground track must ...
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51 views

Can aerodynamic forces move the stabilizer by itself? [duplicate]

So if a plane is accelerating with nose down trim, and the electric trim motors are turned off by the crew, can the aerodynamic forces move the stabilizer and make the situation worse?
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3answers
225 views

How can I calculate the maximum range of an aircraft descending with power (not gliding)?

Let's assume I have an aircraft, for which the thrust is not enough to keep the altitude. So over time I will lose some altitude. But it will still go further then it would without having an engine (...
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If the Concorde had an engine fail at cruise altitude, would they enter the coffin corner?

I know the coffin corner is only meant for subsonic aircraft, but if the Concorde is just cruising at Mach 1 and had an engine failure and also lost that afterburner, would it enter a coffin corner ...
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2answers
238 views

Why does a higher load factor increase stall speed?

I think that’s self explanatory, why does load factor (G) affect stall speed? Why does load factor result reaching the critical angle of attack at higher airspeed?
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6answers
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What is the commercial passenger aircraft top speed record?

Aircraft manufacturers claims commercial passenger aircrafts cruise at the speed of 400-500 knots. But is the top speed of a commercial passenger aircraft recorded (while in air)? If so, what is the ...
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Do modern aircraft still have PCMCIA?

Do modern aircraft still have PCMCIA for engine monitoring?
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1answer
194 views

If the modern airliner was redesigned from scratch, would it look functionally different? [duplicate]

If the modern airliner (Boeing/Airbus) was redesigned from scratch today without any need for "backward compatibility", would it look functionally different from the current design? And if so, what ...
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0answers
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What is the stall speed of the Antonov An-225?

Under certain circumstances - maximum gross weight, unaccelerated 1G flight, clean configuration (landing gear up and flaps)? Indicated airspeed (KIAS) of course.
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1answer
160 views

What is the physical-based/theoretical reason why supersonic area ruling works?

Supersonic area ruling is used to reduce the drag rise that occurs as aircraft pass through the transonic regime. While it has been validated experimentally, what is the theoretical/physics-based ...
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2answers
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Which aircraft can fly at FL600 or above?

I would like to know some examples of aircraft (specific models) which can fly at FL600 or higher. I am interested in aircraft which can or could fly at that altitude on a regular basis (service ...
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1answer
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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 ...
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2answers
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In WW2 aircraft, where were gun cameras mounted, and did they suffer performance penalties?

During WW2, some aircraft had gun cameras that activated whenever the guns fired, so that people on the ground could evaluate performance and help with kill ratios and other statistics. These were ...
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1answer
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Is there a rule of thumb for aircraft design? [duplicate]

I'm wondering how to best scratch build an rc aircraft and what rough proportions the aircraft should be in. I'm aware of the fineness ratio that determines the width to length ratio of a cross ...
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1answer
132 views

What would the point to point range of the current Virgin Galactic Spaceship 2 launch system be?

Many people have suggested that the next step for Virgin Galactic after single point "space tourism" flights begin would be passenger suborbital flights, providing travel times many times faster than ...
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2answers
128 views

Why do airfoils in an airplane's wings have different shape and size along its span?

Why wings of an airplane consist of different shape and size of airfoil. What will happen if the thickness of wing are same throughout the wing?

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