Questions tagged [performance-calculation]
Questions about calculating the various measures of performance of an aircraft.
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How do I determine the engine thrust required to give a specific climb rate?
New pilot here and I am playing around with a flight simulator game for the B737-800. I need some help understanding where/how one can find out if one has enough engine thrust (%N1) to meet a required ...
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Propeller Characteristics at Different Altitudes
Assuming I have a propeller with a given diameter (D), pitch, blade twist, and number of blades, I can theoretically analyze discrete airfoil sections in XFOIL and come up with lift and drag polars ...
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What are the Boeing 777 thrust calculations? [closed]
Can someone show typical calculations for a Boeing 777 jet engine for the following criteria:
Take off thrust of the engine at 170 mph take off speed and 45 degrees F
Cruising thrust required at 500 ...
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How can I determine specific heats of gases for turbojet engine calculations?
I'm in a combustion lab and we are performing experiments on a turbojet engine. However, I am having some trouble calculating the exit velocity and compressor/turbine powers of the engine.
Consider ...
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Why are the positive points in a V-n diagram associated with pitch maneuvers?
For an aircraft with such flight envelope, the flight conditions in point A, C and D are ...
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How to calculate the Gust Envelope?
I am trying to draw the V-n Diagram for a small aircraft I built, but I am stuck in the gust envelope part. I know how it is supposed to look. However, I am having a hard time calculating it. I would ...
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Why do some multi-engine aircraft have accelerate-go distance in their performance charts and some don’t?
I'm curious about why some airplanes have accelerate-stop distance (ASD) and accelerate-go distance (AGD) in their performance charts and some don’t include that. Does anyone know why?
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Calculating Ground Speed - E6B vs Pythagorean Theorem
I have been trying to create an excel formula for calculating the ground speed of an airplane using the TAS, Course, Wind Dir, and Wind Velocity.
The issue that I am finding is that I can't properly ...
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How to realistically model propeller static thrust?
I am graphing static thrust vs prop diameter for a 600 kW motor and a prop diameter up to 5 m. I have seen the post 'What is the equation for calculating static thrust?' and using its formula and ...
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How are the landing, takeoff, and cruise speeds calculated for my homebuilt ultralight?
How can I calculate the takeoff, landing, and cruise speeds of my ultralight with a total weight (with load) of 120 kg, average air density of 1.23 kg/m3, wing area of 13.18 m2, and a coefficient of ...
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How to calculate required thrust for take-off knowing gross weight and L/D?
I know that many variables play into the required thrust for a take-off and for climb. Most of those specs boil down to a targeted gross weight, wing loading and L/D ratio. Intended flying speed range ...
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How do we calculate top of descent (TOD) in flight? [duplicate]
What is the in-flight trick?
I know how to calculate it in theory, but how can I calculate it fast? For example, I know I can use this formula for calculating the rate of descent:
[ground speed + ...
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What experimental techniques should one employ during cruise flight to determine correct airspeed to fly for max range in a headwind or tailwind?
Theory demonstrates that one ought to increase speed in an headwind, and decrease speed in a tailwind to achieve maximum range. A lengthy discussion on the theoretical solution was answered, though ...
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How to perform a "first principle" performance calculation?
I am a PhD student on flight dynamics and control. This week I was given an assignment to do some research on methods of aircraft performance calculation. After some search on the Internet, I found ...
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How to ballpark IAS vs TAS?
Is there some reasonably accurate ballparking formula to allow for quick conversions between IAS and TAS as a function of pressure altitude and difference of ground temperature relative to standard ...
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How should I interpret the Douglas DC-4 approach climb performance chart?
Can someone explain what "C = .04 Vso2" means as the "denotes required rate of climb?". I assumed the point at 6500 ft altitude and 60,000lbs landing weight will mean that the required rate of climb ...
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Does the dew point affect density altitude?
I am looking for the most accurate formula to calculate the Density Altitude (DA) to use it for calculating aircraft performances during landing.
Now I found the following formula:
DA = PA + [120*(...
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Why do DC-4 landing performance charts have different values for the intended and alternate destinations?
I am studying the landing performances of the old Douglas DC-4 and there are a lot of different landing performance charts available. The pilots can use different flap settings during landing like 45, ...
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What is the formula for estimating the maximum stationary thrust of a rotor as function of its diameter?
I am new! New to this forum and new to aviation (i normally deal with statics) so thanks in advance for beeing patient with me.
Recently i was trying to figure out how much weight a rotor can lift as ...
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How to calculate the DC-4 landing distance with this graph?
Can someone give me a clear explanation on how to calculate the landing distance of the Douglas DC-4 with the following graph? And why is the Temperature variable not in the graph, because temperature ...
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What's exactly meant by the "slippery when wet" report on ATIS?
I read this discussion and discovered the definition of "slippery when wet" from this advisory circular but I'm still having a hard time understanding why the runway condition is expressed as "...
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Why does lower atmospheric pressure produce higher EPR (thrust)?
Recently, I read manual about engine, PW JT8D-217A/C, and there is a chart making me so confused.
Manual show the reference table tells you what number, EPR, is normal in specific temperature and ...
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Is there a specific formula or way to calculate flex temperature for an Airbus A320?
I have hear of RTOW charts but I haven't seen any calculations with the runway length or slope. What is the formula or equation to finding flex temperature and V-Speeds?
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Is it possible to determine a rotation speed (Vr) using other known V-Speeds?
Is it possible to come up with a good estimate of rotation speed using other known V-Speeds?
For example: if I know a plane has a Vs @ 55kt. and a ...
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What makes V1 one or two knots less than Vr on this performance table?
(B738 AFM, 0-2000 feet elevation, up to 27°C) Example of V1 and Vr differences.
The table shows that the V1 speeds are invariably one or two knots lower than their matching Vr speeds. Given that V1 ...
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Is reducing V1 a viable option for pilots when the ASDA is shorter than the ASDR?
Let's say you were planning to ferry some passengers and cargo in a jet but after some calculations found out the ASDR (Accelerate-Stop Distance Required) was greater than ASDA (Accelerate-Stop ...
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How does the FOVE system work with the Airbus FMS?
The Flight Operations Versatile Environment (FOVE) is a separate software system used with Airbus aircraft by dispatchers to determine performance data to enter into the FMS. There seems to be little ...
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What calculations are needed for counter-weight balancing on a propeller?
I am designing a small-scale propeller and i have managed to design on optimized geometry for the blade. However the blade pitch angle adjusts according to different flow speeds so i need to mount ...
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How is the zero-lift drag coefficient calculated?
The drag coefficient is usually given as a funtion of the lift coefficient and the zero-lift drag coefficient ($c_{D0}$):
$c_D=c_{D0}+k\cdot c_L^2$
How can I calculate/estimate $c_{D0}$?
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How to calculate the performance parameters of an hexacopter (UAV)? [closed]
I need to calculate the performance parameters like cruise speed, endurance, range of my hexacopter but how can I do that!
Also, is there a way to obtain motor-propeller performance parameters ...
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What are fuel biases?
Does anyone have an idea of what is it? From what I gathered from the web, it seems that this is the margin of error between the actual, real fuel consumption of the aircraft and the fuel consumption ...
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Is there a formula to calculate ground distance traveled given rate of climb and true airspeed?
I'm looking for a formula to calculate the horizontal distance (guess it is the Ground Distance) passed during the phase of ascent (or descent), having the rate of climb in ft/min and the TAS in knots....
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How does blade solidity ratio relate to thrust/power/torque of a propeller?
for quite some time I was using ABBOTT formula for static thrust estimation on a two-bladed propellers:
$$
T=6.8\times10^{-5}\times D^{3}\times p\times RPM^{2}
$$
$T$ is Static Thrust (N); $D$ is ...
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Is there a difference in aerodynamic efficiency between single engine and twin engine airplanes?
I've learned a lot of great information about aviation on this website. One insight I learned from a poster here is that, all else equal, for every doubling of engine power that you give an airplane, ...
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How do you calculate trip fuel based on hourly fuel burn rates?
I am working on a small personal project that uses fuel burn data about specific aircraft to calculate the total fuel required for a trip. The data looks like this:
...
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How can the wind speed and direction be calculated from on-board measurements?
I am currently learning C++ on my own in my spare time. I am writing a little application that will help me while at work. I have come across a situation where I have some given values, but im not ...
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Is the takeoff power always maximum?
I used to think that for commercial aircraft from Airbus, Boeing, Embraer, etc., the take off power was always maximum and selected by the TOGA selection on the thrust levers. But I have been told ...
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How to calculate W/V from true HDG/TRK/GS using a CRP-5 flight computer?
I am currently studying for my EASA ATPL (airline transport pilot license) and one of my subjects is General Navigation.
I have stumbled across this question (picture) that has completely stumped me, ...
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What are the takeoff and landing speeds of a Learjet 45?
I am a fairly new enthusiast to flight simulation.
I would like to know what are the takeoff and landing speeds of a Learjet 45? If they are not fixed, what factors influence those speeds?
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How can this single-prop drone maintain stable (rotating) attitude and position?
The short BBC news item and video The drone designed to fly on one propeller shows the flight of something that looks like quadcopter missing three of its propellors and motors. It continuously ...
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Why is Cessna 172 POH performance chart based on Pressure Altitude and Temperature instead of Density Altitude?
While calculating takeoff distance for Cessna 172, POH need to be used. POH charts has pressure altitude and temperature and then distance for those two known parameters.
Does this mean if we have ...
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why are airplane propellers always undersized?
While calculating propeller static thrust by using a famous Prop-power-calculator.xls (by Pé Reivers),
I've noticed that no matter what "stock" configuration I put into the calculator, I do always get ...
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What is the maths behind the descent rate calculation?
The descent rate calculation states that descent rate is calculated by 'groundspeed / 2 * 10'.
Another document stated that the ground speed should be multiplied by 5 (or more accurately 5.2) to ...
user16863
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Why is "clearway minus stopway" used in V1 adjustments?
Illustrations and/or satellite imagery to explain the difference between clearway and stopway and explaining how they are used by turbine aircraft would be great.
From B787 FCOM.
user14897
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For jets, how can we show that 1/2*ρ*V^2 is equivalent to 1481.3*δ*M^2?
In Roskam's book, we find the following relationship given for climb performance in jet aircraft:
Thrust requested = $D$ = $C_d \cdot (1/2 \cdot \rho \cdot V^2) \cdot S = C_d \cdot (1481.3 \cdot \...
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How to calculate the thrust of a piston or turboprop engine? [duplicate]
This spawns from a related question. Propeller-drive engines (piston/turboprops) seem to always list their output in horsepower or kilowatts, which are units of power.
I want to know the engine's ...
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How does the FAA compute the values in TPP's Climb/Descent Table?
The inside back cover of the FAA Terminal Procedures Publication contains a table headed “CLIMB/DESCENT TABLE,” excerpted below.
Source: FAA, p. 19
How do required ascent or descent ...
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How can true altitude be calculated from pressure altitude, temperature and altimeter setting?
The manual that came with my Jeppensen E6B has the following sample...
If an aircraft is flying at 12,500 feet with an outside air
temperature of -20C and the altimeter is set on 30.42 inches of
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How do you convert true airspeed to indicated airspeed?
Is this something found in the POH? I know there is a IAS and CAS chart.
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How do you calculate indicated airspeed on a flight plan?
I'm planning my cross country journey for my flight test and it seems I forgot how to calculate my indicated airspeed.
The indicated airspeed must be from the POH, right?
The the true airspeed is ...
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