# Questions tagged [performance-calculation]

Questions about calculating the various measures of performance of an aircraft.

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### Can this plane make it to an airport after dual engine failure?

If you are flying to the most remote airport(according to simple flying most remote airport is Mataveri International Airport), while flying on a typical airliner with normal weather, in the event of ...
• 3,337
1 vote
114 views

### Determining Required Fuel from Payload/Range Diagram

I would like to determine the amount of fuel required for a flight at a given range/payload combination - ideally from the payload/range-diagram [1] of the corresponding aircraft alone. I know that ...
• 1,704
214 views

### Why is higher V1 preferred over lower V1 in takeoff performance calculations?

I am using a takeoff performance application that seems to prioritize a higher V1 speed whenever there is extra runway available. It does this as long as the Acceleration-Stop Distance (ASD) remains ...
• 75
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### What are the parameters typically used by airlines to assess the fuel economy and efficiency for their flights?

Are there parameters that are typically being used by airlines to assess the fuel economy and efficiency done in their flights? And how exactly those parameters are being used to do the assessments ...
115 views

### How do you calculate the theoretical vertical speed of an aircraft? [duplicate]

I'm doing this for a High School research paper, so it would be preferable if little calculus is used for any calculations (up to Calculus I is probably okay). This should be based off of the flight ...
850 views

### What are the standard numbers for fuel consumption (kg), kg/NM, and kg/h, of Boeing 737-300?

I'm currently working on a school project regarding the analysis of Boeing 737-300 fuel consumption. I'm working on some parameters that my supervisor gave me, which are : Total fuel consumption (kg),...
78 views

### Material Shape Parameter (n)

In order to calculate the plasticity reduction factor given in Michael C.Y. Niu's book a constant (n) is being multiplied which is called the material shape parameter, does anyone know the meaning of ...
433 views

### 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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### Are UDF/Propfan Engines Thrust Producing or Power Producing? [duplicate]

For the purposes of aircraft performance (best endurance/range speeds, Vx, Vy, etc.) would a propfan be considered a power producing engine or a thrust producing engine? I would imagine it would be ...
245 views

### For a fixed density altitude, how does climb performance depend on pressure altitude?

Below is the climb performance from the 1978 Cessna 152 POH, which I've plotted as climb rate versus density altitude. It shows that higher pressure altitude gives decreased performance even when the ...
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### Is there an equation to solve for bank angle using load factor and wing loading as variables? If so, what is it?

The problem is that I'm looking for both wing loading and load factor as variables to solve for bank angle and cannot find any equation that represents this. After searching various websites and not ...
164 views

### 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 ...
1 vote
354 views

### Question about V1 Vr V2 computations

On ASA’s ATP test book they mention the following: “V1 is computed using the actual airplane gross weight, flap setting, pressure altitude and temperature.” I understand that v1 gets adjusted for ...
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### Confused about screen height definition

I’m a bit confused about screen height definition and I’m seeking help to understand it. I understand that this height for landings is at least 50 ft above the landing threshold for all airplane ...
• 159
1 vote
332 views

### Dispatch Landing vs. Inflight Landing Performance Calculation

What is the difference between Dispatch Landing and Inflight Landing Performance Calculations? Are you obliged to use both? Specifically concerned with EASA rules.
• 75
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### Help me understand the A220-100 takeoff chart

Here is the takeoff performance chart of the Airbus A220 (CS100). According to Wikipedia, the MTOW runway length needed is 1500 metres. However, this chart seems to suggest that a runway length of ...
• 225
1 vote
298 views

### How would Vy be adjusted for changes in gross weight?

For piston propeller aircraft, Vy calibrated airspeed[CAS] is equal to CAS for best Lift/drag at the plane's absolute ceiling, and at lower altitudes Vy increases above best L/D as excess power is ...
• 2,604
928 views

### takeoff and landing distance GRAPH for a Cessna 150

I cannot find a takeoff and landing distance GRAPH for a Cessna 150. The C172 is easy to come by but why no C150?
• 31
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### Is there a simple formula for estimating supercharger throttling losses?

I’ve noticed that in both Aerodynamics for Naval Aviators, and most old WWII engine power charts, power vs altitude seems to be composed almost entirely of linear relationships: at a given ...
1 vote
641 views

### what is ''extended runway centerline''?

When we calculate performance with fly smart，we see：‘‘Take off based on climbing on extended runway centerline‘‘. What is the meaning of‘‘extended runway centerline‘‘？How long is Extended？
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### How to measure fuel level from uneven tank?

If you measure the fuel level with a dipstick on the C172 I fly, you can get two different readings. This is because directly under the filler cap opening there is a cuboid-shaped sensor. Obviously, ...
1 vote
153 views

### Why does the airplane manual state S1 is equal to or greater than the higher of ground minimum control speed or critical engine failure speed

I don't understand why S1 is equal to or greater than the higher of Ground Minimum Control Speed or Critical Engine Failure Speed (Vcef). I do understand that S1 has to be the lowest of Refusal Speed, ...
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### How to calculate boundary layer thickness?

So I have a flat plate with a surface of 7sqm and an aspect ratio of 12 with air blowing straight at it (like a wing) at a speed of 50km/h. I would like to manually calculate the thickness of the ...
446 views

### What is the meaning of "airport pressure altitude" on a flight performance graph?

In a flight performance graph what is the meaning of airport pressure altitude? Is it the top of climb? Because if I set my altimeter to 29.92 it will give me the pressure altitude for an airport at ...
1 vote
887 views

### Calculating center of gravity when calculated CoG, T/O mass, fuel burn and fuel burn station are known

I'm practicing for my EASA PPL(A) exam and one of the questions I came across sound like this: Calculated take-off mass = 1082 kg, calculated CG = 0.254 m, fuel burn = 55 l on station 0.40 m. A. 24.6 ...
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### How is Fuel needed to be consumed calculated when MTOM and Actual Mass is known

I'm practicing for my EASA PPL(A) exams and one of the questions I came across looks like this: How much taxi fuel must be consumed before take-off to reduce the aircraft mass to the maximum take-off ...
• 397
1 vote
681 views

### How to calculate the climb performance of an A320

Recently I have been taking off in Innsbruck (LOWI) with my A320 (in Microsoft Flight Simulator, because I cannot afford the real one) and quickly found myself greeted by a GPWS Warning: "Terrain ...
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### Why do helicopter performance charts for hover out of ground effect (HOGE) have a "knee"?

Have a look at the following performance charts from Section 5 of Robinson R-22 Pilots Operating Handbook for hover out of ground effect (HOGE). If the temperature and gross weight are known, the ...
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1 vote
131 views

### Why does V2 decrease for intersection takeoff

I have noticed that the VR and V2 decreases for same FLEX when departing from an intersection runway even when sufficient stop margin is available. What is the reason for this? And also does EFB ...
163 views

### How useful were the wings and tail of Jean-Pierre Blanchard's balloon?

In 1784, Jean-Pierre Blanchard fitted a hand-powered propeller to a balloon, the first recorded means of propulsion carried aloft. In 1785, he crossed the English Channel in a balloon equipped with ...
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106 views

### Are there significant differences between EASA and FAA when teaching jet aircraft performance?

Both regulatory bodies did a great effort in regulation harmonization, but I'm looking for any significant differences (if any) in how is taught the subject from the pilot point of view, i.e. ...
• 1,383
361 views

### 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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### Do pilots of piston/prop aircraft have discretion to determine how much runway is required for an intersection departure?

For piston/prop aircraft requesting intersection departure, is it pilot discretion for the minimum amount of runway length required? Is there a takeoff calculator in conjunction with calculations?
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### How does a fighter pilot calculate approach/landing speeds?

Let's say an F/A-18C returns to land after expending some payload. Fuel burned and weapons released made the plane lighter. I guess the aircraft computer can tell the pilot the actual weight of the ...
• 1,383
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### Takeoff distances published in OEM manuals

Background For academic research purposes, I have developed a first-principle takeoff performance model that returns a takeoff distance required (TODR) based on the aircraft type (incl. its associated ...
1 vote
319 views

### How to read performance chart? [duplicate]

From the Flight Planning and Performance quiz for PPL, there is a question asking to calculate the distance needed for landing over 50ft barrier. According to the example shown by the manufacturer (...
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### Why is maximum zero fuel mass used in take off mass calculation?

In calculation we consider maximum takeoff weight , maximum landing weight and maximum zero fuel weight we selected the lowest of below mentioned Maximum Zero fuel weight + Take off fuel Regulated ...
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### Is there a way to calculate the braking distance for a light aircraft?

PPL student, I train in a C152. Reviewing its POH I cannot find a method to estimate brake performance roll (as I would do with T/O roll). Is there any method or rule to calculate brake roll in ...
• 707
621 views

### Why does Vr increase with lower air density and decrease with higher air density?

Can someone explain why Vr increase with lower air density and decrease with higher air density? I read such a phrase in my ATPL(A) performance textbook, but without further explanation. As far as I ...
• 2,035
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### Why does V1 increase with headwind and decrease with tailwind?

Can someone explain why V1 increases with headwind and decreases with tailwind? I read such a phrase in my ATPL(A) performance textbook, but without further explanation.
• 2,035
970 views

### Can the energy dissipated in a power-off descent be calculated and expressed in horsepower?

If the weight in pounds of an aircraft is known along with its sink rate in feet per minute at best power-off glide conditions, can the horsepower being dissipated by drag as the plane descends via ...
• 21.3k
987 views

### Why do we calculate 25% more of TODR?

In general aviation aircraft, we are being told to calculate TODR (takeoff distance required) using AFM and TODR x 1.25. Why do we need the value with 25% added?
275 views

### I don't quite understand the derivative in this vertical wind gust formula

First my english writing skill is still bad so pardon me if i accidentally made any mistake TT-TT. So recently I have learnt about how the vertical gust affect the load factor and the calculation ...
3k views

### Why do we still interpolate in performance tables?

I'm getting my Private Pilot License. In the coursework, we learn about flight planning, which requires looking at performance charts for your particular aircraft. These charts in my case are tables ...
531 views

### Is a ducted fan considered a jet or propeller for the performance parameters?

Right now I am working on a UAV design which will use ducted fan. But the performance calculations are a bit troublesome. For some calculations jet and propeller results are almost same but for the ...
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### Should a runway overrun be expected if takeoff is begun with one-engine-out?

Multi-engine aircraft have enough power to successfully takeoff if one engine fails after V1. But what if, on a runway equal to the specified takeoff distance, someone decided to roll with one engine ...
664 views

### Why is my calculated seat-miles per gallon of small aircraft higher than of big aircraft?

I've calculated the seat-miles per gallon for three planes. This factors in the speed; it basically means how much does it cost to transport 1 person 1 mile. Plane Seats Cruise (MPH) gph seat-mpg ...
1 vote
173 views

### What power have I obtained?

I am currently working on a question in aeronautical engineering. The question has asked me to provide the available power. I have calculated the drag, and am given the constant velocity. With that, I ...