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.

Filter by
Sorted by
Tagged with
1
vote
1answer
82 views

Flying a twin engine aircraft with 2-axis control

I believe a twin engine aircraft, with 2-axis control (i.e. Rudder and Elevator), under normal circumstances is flyable. But is it safe at all? If one of the engine dies, will the rudder alone be ...
1
vote
0answers
47 views

Are there any lift or lift coefficient equations which factor in the flap deflection angle?

I'm asking this because I tested a NACA 2412 wing with an adjustable flap in a subsonic wind tunnel and I'm getting the lowest Cl values for the highest flap deflection angle.. which to my knowledge ...
4
votes
2answers
258 views

What is the impact of thermal Anti-Ice on descent performance?

I am just another one of the passionate flight simmers trying to understand more about Anti-ice system mechanics. I am talking about the Boeing 737-800 here if it makes a difference. What bothers me ...
1
vote
0answers
58 views

What is the maximum (unloaded) range of the Beluga XL?

Airbus states that the range of the Beluga XL is 4000 km at maximum payload. Does anyone have a figure (or estimate) for it's maximum range with no payload?
1
vote
1answer
48 views

Can accelerations be used to calculate load factors?

Can I use the z accelerations to calculate the load factor in that axis? Please explain how or why not.
5
votes
3answers
280 views

How do flaps help an aircraft take off at a lower speed, yet cause drag at the same time?

Wouldn’t the drag caused by the flaps just decrease the acceleration, so, although they can lift off at a lower speed, wouldn’t it be faster to just use no flaps and rotate at the higher speed that is ...
0
votes
0answers
61 views

What's the difference between hover power and maximum continuous power?

What's the difference between hover power and maximum continuous power? Is a pilot clear to fly when its hover power is more than maximum continuous power calculated by table?
0
votes
4answers
184 views

What makes airplanes pitch up during landing?

So what exactly pitches the plane upward with the rear end down? Do flaps help lower the nose when deployed 80%-100% down with such low speeds?
3
votes
5answers
206 views

How much of an airplane's forward energy is lost to lift?

An airplane needs to move forward to generate lift, and because energy isn't created from nothing, all the kinetic energy of lift comes in the form of drag, where air (air resistance) turns forward ...
40
votes
6answers
14k views

Do airplanes need brakes in the air?

A few days ago I flew on a Boeing 737-900ER. Luckily I was sitting just beside the left wing, seat 26B. I observed that the spoilers were activated (opened) just after the pilot spoke on the Passenger ...
2
votes
1answer
92 views

What is the range difference between LEAP and PW1000 powered A320 and A321 NEOs?

Mounted on the same aircraft, PW 1000G and CFM LEAP are two very different engines, with different performances, that should have an impact on range. And we know range is a very important aircraft ...
2
votes
0answers
82 views

How can I approach analyzing the basic performance characteristics of an unknown aircraft?

I am working on a project for one of my classes. My group and I have been given information on an unknown aircraft, and we must find the max velocity, max R/C, max range, and max endurance of the ...
2
votes
1answer
54 views

Why does lift curve slope increase when Fowler Flaps are deployed?

Below is an image for a Fowler Flap: Notice that as the flap is deployed, both the camber and the area increase. This change in wing shape modifies the lift curve as follows: (source: Development of ...
0
votes
1answer
160 views

Why do pilots wait for a positive rate to put the gear up, When V1 means “commit to takeoff”?

To explain further, V1 means they cannot stop in time if anything happens. Therefore they must commit to taking off. So why wait for a positive rate? Shouldn’t it be retracted as soon as they see a ...
0
votes
2answers
279 views

What is an airliner pilot's first go-to if he or she doesn’t have a positive climb rate immediately after take off?

Take for example a 737. Would the pilot just lower the nose to pick up airspeed, then raise it back up once they’re satisfied? Or maybe retract the flaps a bit? Assuming the throttle is at 94% N1, ...
-1
votes
1answer
112 views

How can a runaway trim become so difficult to fight when all a pilot has to do, is “grasp and hold?” [closed]

and how can you even tell the pilots did “grasp and hold” during an investigation? Is it determined based off what they say?
0
votes
1answer
79 views

Is there a relationship between transonic buffet magnitude and altitude?

Transonic buffet happens at mach 0.95. The correlated true airspeed varies with altitude. Does the transonic buffet magnitude also vary with altitude, and if so, how?
0
votes
1answer
84 views

External Batteries [closed]

As a part of a project for a class we were tasked with trying to cut emissions/energy waste of airplanes. Now we've realized that running the apu on the ground at the gate and taxiing is a serious ...
3
votes
1answer
137 views

Do aircraft need special modifications for polar routes?

Does an aircraft need special modification for polar routes?
1
vote
1answer
171 views

Where and when would a 737-700 be taking off at an altitude of 19 kft?

Another question triggered by reading the 737 technical site; according to this section of the page on the 737's pressurisation system, the 737-700 comes with an option that allows it to safely take ...
2
votes
1answer
111 views

Why does IAS decrease with lower air density if power is constant?

TAS increases with less dense air, which is intuitive. What I don't understand is why IAS decreases. This is assuming sub-transonic speeds where compressibility effects are negligible. To phrase ...
3
votes
2answers
184 views

What is the explanation of this airfoil phenomenon? Why the air from below the leading edge's tip deflected up?

I have difficulties to understand this air phenomenon, why the air from below the leading edge's tip (from below the horizontal line) is deflected up and not just follow the bottom wing's surface? ...
1
vote
0answers
166 views

If an fighter jet that it have twin rudders, in use the angle of deployment it is not identical. Which is more deflected and why?

If an aircraft have two vertical tails then pilot push in the rudder pedal the rudders will not be deployed at the same angle.It is used throughout the all envelope of flight or is it possible only ...
0
votes
1answer
57 views

How many tendencies are affected by Gyroscopic precession for single propeller airplane?

I have heard about LEFT turning tendency affected by gyroscopic precession of propeller (which is turning clockwise or counter clockwise if seen from front side). But I just watched a video on Youtube ...
0
votes
0answers
92 views

In flat spin is rudder deflection used for recovery of the F16?

If the horizontal tails is used due MPO switch in recovery of the flat spin, is the rudder used for stopping the yaw of the F16 ? I know that for inverted flat spin is surely used, but I believe ...
-2
votes
3answers
219 views

Why the pitch control of helicopter is named Collective Control? And why does it located at the left side of the pilot seat?

This is probably a very trivial for some of you. But sometimes a name not representing the function become a question, just like this Collective Control, which its function is to pitch up the blade ...
3
votes
1answer
82 views

What is a Second Segment Weight Limit?

I am very interested in the principles of take-off performance optimization. During my research I found an interesting picture, showing the software used by a European carrier. However, the output ...
7
votes
2answers
2k views

Why is the empennage design of this Lockheed 1049E so complicated?

Photo. What is the reason for making the empennage of this Lockheed L-1049E Super Constellation's design look so complicated with two vertical horizontal stabilizers? In my understanding, the more ...
0
votes
0answers
79 views

How does the maneuverability of the FJ-2 Fury and F-86 compare?

The North American FJ-2 Fury was the US Navy version of the F-86 Sabre jet. I want to know if G maneuver limits were in favor of the F-86 or the FJ-2 Fury.
1
vote
1answer
67 views

How do I get a copy of a Pilot Operating Handbook? [closed]

I need the POH for a Cassutt Plus or any variation for a University Project but I can't seem to find anything on the plane. Any other information (flight capabilities etc) would be helpful - with ...
1
vote
1answer
58 views

What is the differance between gliding for maximum range and gliding for maximum endurance? [duplicate]

Is there a difference between gliding for maximum range vs. endurance? Is the glide speed the same for max. endurance and max. range?
1
vote
1answer
92 views

What are the take-off parameters for the B-25 Mitchell?

What is the take-off distance and speed in standard atmosphere (59°F, 29.92 inHg, 0% humidity) for the B-25 Mitchell with max, minimum, or average payload?
2
votes
0answers
78 views

Can the assumed temperature be lower than the flat rated temperature?

I was playing with reduced takeoff thrust in a Boeing 737-800 simulator yesterday and was surprised that I could enter assumed temperatures below the flat rated temperature of the engines. The ...
7
votes
2answers
2k views

Would a 737 pilot use flaps in nose dive?

Since flaps help lift the plane, would they deploy flaps if the plane was nosediving? And what would they do if the back pressure was too much? I know speed increases lift, but can full throttle make ...
6
votes
5answers
3k views

How much horsepower to weight is required for a 1:1 thrust ratio?

I did a math experiment today, but wanted to verify the results. I wanted to figure out how much horsepower is needed for an aircraft to hover in midair with no wings/lifting body (1:1 thrust/weight)....
0
votes
1answer
105 views

What is the average climb gradient of an aircraft during the takeoff and early phase of a departure procedure?

On chart plates it is written the minimum climb gradient with which an aircraft should climb for obstacle clearance or after ATC request (for traffic flow management etc.). However, since this is the ...
5
votes
2answers
308 views

Why are the engines of the Airbus A400M slightly tilted down?

Picture: Youtube. Firstly, are the engines really tilted down? I have tried to check another picture over the net, seems they are really tilted down slightly. But need confirmation from you experts, ...
2
votes
1answer
263 views

Why couldn’t Boeing just use the stab trim system to do MCAS job?

If I’m incorrect in the question, please correct me. From what I’ve read and gathered the stab trim system essentially did the same before hand? It relies on AoA? And if so, did the computer for that ...
1
vote
2answers
145 views

Does the AOA and G-Force increase if a fighter uses the afterburner during a max G level turn?

My understanding is that if you apply power (increase the thrust) for a jet in level flight, it will momentarily pitch up, and then gain some speed. So, if a fighter pilot lights their afterburner ...
2
votes
3answers
161 views

What is lifting force of V-22 Osprey? Is any other than the two rotors?

Picture is from here. Is any other force to lift the V22 other than its rotors? Is any possibility that the power plants their self are not generating thrust? I was just wondered that such short ...
2
votes
1answer
187 views

Why is an F22 slower than an F15?

An F22 has a higher thrust to weight ratio. The F22 has around ~70,000lbf thrust from its F119 engines, where as the F15 has around ~48,000lbf thrust from its F100 engines. But every metric I can ...
1
vote
1answer
52 views

Calculate parasite drag coefficient from drag polar

The drag polar of an electric-powered unmanned aircraft is $$ C_D = 0.038 + 0.0458 C_L^2 $$ What is the parasite drag coefficient?
14
votes
4answers
3k views

Why there so many pitch control surfaces on the Piaggio P180 Avanti?

Picture source. I have seen that there is kind of sonic aircraft like B-1B Lancer that used elevator and canard or fins at the same time for pitch control. That quite understandable because it is ...
13
votes
1answer
5k views

Why does Canada recommend a minimum rate of climb for ultralights of 300 ft/min?

What is a safe minimum rate of climb for ultralights? I understand most ultralights climb at least 300-800 ft/min and in fact the Canadian ultralight specs recommend a minimum rate of climb of 300 ft/...
5
votes
4answers
1k views

What are the advantages and disadvantages of tail wheels that cause modern airplanes to not use them?

Photos' source: Cessna 140 and Cessna 150. According to Wikipedia here, the Cessna 150 is successor of Cessna 140. Both have two-seat capacity and a single engine. Why was the Cessna 150 changed to ...
3
votes
1answer
92 views

Does lift coefficient for maximum range change for a glider experiencing headwind?

When a glider or unpropelled aircraft experiences headwind, I understand that the flight velocity and sink velocity for the "new" maximum possible range both increase (see velocity polar from How does ...
3
votes
1answer
150 views

Why does the spool speed increase with altitude for a turbofan engine (single spool & double spool)?

So, I want to see the effect of altitude on the compressor characteristic of a single spool & double spool turbofan engine at constant flight speed and TIT (turbine inlet temp). I am aware that ...
1
vote
2answers
248 views

What bank angle creates the least energy loss in an emergency engine out 180 degree turn? [duplicate]

A situation we all hope to never have: engine quits at a low distance AGL. What bank angle will produce the least altitude loss for a 180 degree turn? Is this common for all aircraft? Readings have ...
20
votes
4answers
4k views

How does turbine efficiency compare with internal combustion engines if all the turbine power is converted to mechanical energy?

It is widely know that early turbojets guzzled fuel and created thrust simply by spewing accelerated matter out the back. Modern jets have come a long way in earning a better reputation with ...
0
votes
0answers
40 views

Non-dimensional variables choked nozzle

I understand that a choked nozzle removes the dependance on the static pressure $p_a$ because if M>1 in a choked nozzle then waves cannot travel upstream in the nozzle (as explained in the paragraph ...