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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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F15 Startup Intake drop

So I’m aware that the F15 has intake Ramps that adjust to airspeed and AOA, in order to ensure that the airflow is entering the engine smoothly and not too fast. But why does the system drop the first ...
Boeing787's user avatar
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9 votes
3 answers
1k views

Does weight of an aircraft affect its ability to pull G?

This question includes the quote: A C42 doesn't weigh much, so to pull the 5+ G required to exceed the design specifications of it's wing spar and fixings would require extreme speeds. I'm not an ...
DJClayworth's user avatar
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5 votes
3 answers
136 views

How can I find the minimum and maximum airspeeds for efficiency with a specific prop/engine combination?

I'm operating a Cessna 180 with various wing and weight mods with a TCM IO550D engine and a McCauley Black Mac (D3A34C401/90DFA-2 3 blade (88 inch) seaplane prop. I operate Lean of Peak (LOP) for most ...
DustyFlier's user avatar
4 votes
1 answer
91 views

How does the lift-to-drag ratio depend on absolute sizes?

A dependency is provided here $$(L/D)_{\max} = \frac{1}{2} \sqrt{\frac{\pi \varepsilon ~ \mathrm{AR}}{C_{D,0}}}$$ AR significantly affects the outcome in this dependency. AR varies significantly among ...
Imyaf's user avatar
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-5 votes
1 answer
185 views

Why use the F-35

The F-35B has been troubled by "problems with its stealth coating, sustained supersonic flight, helmet-mounted display, excessive vibration from its cannon, and even vulnerability to being hit by ...
VFA-34's user avatar
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0 answers
37 views

What is the landing requirement for Klein Vision AirCar?

The Klein Vision AirCar is said to require a runway of only 1,000 ft and a speed of only 75 mph for take off. But I cannot find any information on its landing requirement such as: Minimum runway ...
GratefulDisciple's user avatar
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60 views

What was the fastest single engine plane with predominantly wood frame and fabric skin construction?

I've been doing some research and I haven't found a satisfying answer. The Mosquito was quite fast but it was wood skinned and had two engines. The Bellanca Viking was fabric skinned but used a metal ...
WhiskeyHammer's user avatar
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2 answers
190 views

How much fuel can be saved in a half full of passengers plane?

On a typical airliner (let's say A320 / B737 / or similar), comparing a plane full of passengers vs one half full, how much fuel an airline can save on a trip when the plane is only half full? (This ...
Gabe's user avatar
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9 votes
2 answers
3k views

Is there a valid case to do the imposible turn(180)?

It has been said many times not to do the imposible turn(180) after takeoff since almost always it ends in a fatal crash. My question is, if you are flying a Cesnna 172, or any single for that matter,...
Gabe's user avatar
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5 votes
1 answer
135 views

Comparing a Flight In Turbulent Conditions At Va And Vb

First, let's cover definitions for both airspeeds: Turbulence penetration airspeed (Vb) is the design speed for maximum gust intensity (i.e. the intersection between the 66 fps gust line and the ...
Darjan's user avatar
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Lift distribution of a swept wing with twist, dihedral, taper

I am trying to get the lift distribution of a swept wing with taper (in chord and thickness along the span), twist, and dihedral. I know that Kuchemann Index method is used for swept wings but I am ...
RNG's user avatar
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1 vote
0 answers
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How to calculate EGT Margin for P&W engines (PW1100g) ? (Theta parameter correction)

My goal is to obtain engine baselines and calculate EGT Margin for Pratt&Whitney PW1100g engines (specifically, PW1133GA-JM) I have a large dataset of engine reports recorded during takeoff. I ...
Bogdan's user avatar
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2 votes
0 answers
116 views

What is the precision of the Fuel Quantity Indication System (FQIS) of the Boeing 777?

What is the precision of the Boeing 777-300ER ultrasonic FQIS? If for example it is 2% when 100 tonnes of fuel are loaded, there could be anything between 98 tonnes and 102 tonnes. How is this ...
FlyARP's user avatar
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7 votes
4 answers
513 views

Which airplane has the biggest ratio of Vne to stall speed?

Of airplanes that cannot hover (rotorcraft, VTOL), which one has the biggest ratio of $V_{NE}$ (speed that it may never exceed) to stall speed? To be precise, "stall speed" here means the ...
Camille Goudeseune's user avatar
0 votes
1 answer
71 views

Can a single-bladed rotor with cyclically varying torque emulate a swashplate?

Instead of a swash-plate cyclically varying the pitch of the rotor blade(s), could a similar effect be generated by cyclically varying the thrust of the motor on a fixed-pitch single-blade rotor? The ...
Albeit's user avatar
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3 votes
4 answers
598 views

What are the correct Cd0 and Cdi values for a NACA 2412 airfoil?

According to an answer to this question, at best L/D the the drag coefficient is evenly split between Cd0 and Cdi. I'm going to limit the question to the Cessna 172 and its NACA 2412 wing with an ...
Robert DiGiovanni's user avatar
1 vote
1 answer
106 views

Computing the eigenvalues of the longitudinal dynamics _analytically_: is there a method to simplify the task, or must it be brute force?

I understand how to go about finding the eigenvalues and eigenvectors in principle, in order to distinguish the phugoid modes, but the first exercise in Lavretsky & Wise tells to compute those ...
avs's user avatar
  • 111
0 votes
5 answers
325 views

How/why does engine torque and horsepower affect aircraft speed? [duplicate]

I'm curious as to why torque and horsepower affect an aircraft's speed. AFAIK, it's only the engines RPM that affect speed, right? Does this mean an engine's torque/horsepower only affects the speed ...
aleks lacroix's user avatar
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How do you determine VMCG, if its yawing moment by the inoperative engine is only be corrected by the rudder?

The requirement of VMCG is: VMCG, the minimum control speed on the ground, is the calibrated airspeed during the takeoff run at which, when the critical engine is suddenly made inoperative, it is ...
TRON's user avatar
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50 views

Does the downwash velocity calculation apply to hovering flight? [duplicate]

After reading a very interesting interplay between two writers attempting to answer this question of helicopter downwash velocity, it occurred to me that, although this calculation: $V_i = \sqrt{\...
Robert DiGiovanni's user avatar
0 votes
2 answers
122 views

Where can I find aircraft design data? [closed]

I am looking for a library of different aircraft data, variables such as coefficient of lift, drag, etc. I've gotten access to the POH/AFMS and the FAA TCDS' but they often modify the core data for ...
JeffreyMG's user avatar
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2 answers
147 views

Is less right rudder pressure needed for right chandelles

It is said on the Internet and the FAA Airplane Flying handbook that when rolling out from a right chandelle, the yawing moment is to the right, which partially cancelled some of the left turning ...
Hitomhi's user avatar
  • 349
5 votes
1 answer
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Why single engine turbine helicopters can operate on higher altitudes than multi engine helicopters?

Probably you knew the example where H125 landed on Mount Everest (8848 m), and H145 highest landing was on Aconcagua (6962 m), almost 2000m difference.
cirica's user avatar
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What is the effect of changing RPM on pitch attitude?

Considering a light aircraft like C172, what happens to pitch attitude of the aircraft when increasing or decreasing RPM? And more importantly why this happens?
AIRWAYLOVER's user avatar
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0 answers
127 views

IDLE Factor determination

The Flight Management System (FMS) utilises the Idle Factor to modify the computation of the vertical profile whilst descending. During this phase, the FMS calculates the vertical profile and ...
alQ's user avatar
  • 75
2 votes
1 answer
203 views

A transfer function relating jet engine thrust to pitch angle during a phugoid motion

Crossposted on Mathematics SE I am doing a school project that requires me to find a transfer function that relates the thrust of a jet engine (which could change with time in one way or another) and ...
Faito Dayo's user avatar
0 votes
2 answers
99 views

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 ...
Sauerkraut9's user avatar
2 votes
1 answer
240 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 ...
Chris's user avatar
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0 votes
1 answer
155 views

Why are these characteristics of the FT-180 highlighted?

I have been checking the FT-180 engine used to establish speed record for remotely controlled aircraft (i.e. model airplanes). There are some specific features highlighted on the manufacturer site. I'...
totalMongot's user avatar
2 votes
2 answers
748 views

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 ...
Aasena's user avatar
  • 23
0 votes
0 answers
46 views

climb angle of 737-800 performance [duplicate]

I am doing a report on 737-800 and I have questions about its climb angle performance; I am plotting a climb angle VS altitude graph for the aircraft, why does the climb angle take off at an angle and ...
user65712's user avatar
2 votes
1 answer
585 views

Why does the climb angle of 737-800 peak shortly after take-off before reducing again?

I am doing a report on 737-800 and I have questions about its climb angle performance; I am plotting a climb angle VS altitude graph for the aircraft, why does the climb angle take off at an angle and ...
user65712's user avatar
1 vote
0 answers
75 views

Engine Performance Data for GE F414-400

I am currently in Capstone for ASE, and for our course we have been tasked with reverse engineering the X-59 QueSST created by NASA and Lockheed Martin. I am the propulsion lead for our team and I ...
Derrick John's user avatar
3 votes
1 answer
400 views

How would you know the difference between a compressor stall and a surge based on indications in the cockpit?

I understand the difference between a compressor stall and surge. Stall: One or two blade stages exceed the critical AoA, the airflow is turbulent, and the smooth airflow through the compressor is ...
Breaach's user avatar
  • 159
1 vote
0 answers
153 views

Is my understanding about Balanced Field correct?

We have two definitions: Balanced Field where Takeoff Distance Required = Accelerated Stop Distance Required Balanced V1 = This is the speed where on a balanced field length (TODR=ASDR) if we have ...
Breaach's user avatar
  • 159
0 votes
1 answer
97 views

What are the effects of whiteout (snow) and brownout (sand/dust) on helos?

Is there any other effect besides low visibility? Both seem to show very similar conditions.
BanzaiFighterbomber's user avatar
0 votes
0 answers
233 views

What type of ailerons does the Piper Seminole has?

I understand that the PA44 has differential type ailerons, but do they also have frise type ailerons? Making them a combination of differential and frise type similar to the Cessna 150/152/172 models? ...
Breaach's user avatar
  • 159
0 votes
0 answers
30 views

Is the Lift required for a steady-state climb and descent equal for the same absolute value of the kinematic climb angle? [duplicate]

Here is my confusion : I found in my lecture script the following equation for the steady-state climb and descent (wings level) ...
Christian Mändle's user avatar
1 vote
2 answers
172 views

What differences would a helicopter designed to withstand many negative Gs have compared with a normal one?

There are a few helicopters that are able to take negative G's, and to this day only one can actually perform aerobatics (ie. Chuck Aaron's BO-105). The BO 105 is a rigid rotor helicopter that has ...
BanzaiFighterbomber's user avatar
6 votes
2 answers
3k views

Why is a flat turn less efficient than a coordinated turn?

How I understand a flat (rudder-only) turn: AOA between relative wind and the fuselage of the airplane causes a sideslip in the direction of yaw. Vertical stabilizer weathervanes into the relative ...
astroball's user avatar
1 vote
1 answer
209 views

Is the Reference Speed (Vref) the same as the speed at which the aircraft cross the runway threshold in landing phase?

Just a little confuse when I learned about the aircraft classification based on approach speed. Can anyone help me to have an accuracy look about this question?
Harry Huynh's user avatar
-1 votes
1 answer
381 views

What velocity is used to calculate maximum range and maximum endurance?

These are my data; $C_{L_0} = 0.4$ $C_{L_{\alpha}} = 5.7$ $C_{L_{minD}} = 0.14$ $C_{D_{min}} = 0.022$ $k = 0.035$ $\alpha_{stall} = 15$ $S_{ref} = 20m^2$ Mass Data $W_{total} = 2500 \text{ kg}$ $W_{...
Bugra's user avatar
  • 11
1 vote
2 answers
173 views

Can vortex ring state (VRS) be solved by shaping the blades so that the vortexes they produce are weak enough not to form a vortex ring?

Vortex Ring State is one of the hazardous states a helicopter can find itself into. VRS happens when a helicopter has low airspeed (and usually hovering OGE) and is descending. If the helicpoter is ...
BanzaiFighterbomber's user avatar
1 vote
2 answers
255 views

Does the ground effect change with temperature changes?

The title is my question. Does the ground effect change as the temperature of the ground changes? In cold weather, a more cushion effect can be expected, and in hot weather vice versa?
lemonincider's user avatar
  • 7,565
1 vote
1 answer
315 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 ...
Breaach's user avatar
  • 159
0 votes
1 answer
1k views

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 ...
Breaach's user avatar
  • 159
0 votes
2 answers
123 views

Can supercharger/turbocharger increase absolute ceiling

Superchargers and turbochargers can increase the service ceiling. Then what about the absolute ceiling? Can superchargers or turbochargers increase it?
Hitomhi's user avatar
  • 349
8 votes
4 answers
3k views

If I am at absolute ceiling, can I climb further by trading airspeed for altitude?

If I am flying at absolute ceiling, can I still climb by trading airspeed for altitude?
Hitomhi's user avatar
  • 349
1 vote
1 answer
88 views

What are the key differentiating factors between the flight control systems employed in unmanned drones and those utilized in piloted aerial vehicles?

"I've come across open-source projects like ArduPilot that are commonly used with microcontrollers like Pixhawk for unmanned aircraft. However, I'm unsure whether these systems can be adapted for ...
Rohit Anand's user avatar
16 votes
2 answers
4k views

Why is this plane indicating an altitude of 117,200 feet?

Looking at a plane tracker, I found something where the altitude is crazy high. Could it be a plane masking identity?
Josh's user avatar
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