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
2
votes
1answer
65 views

BHP increases with Altitude

Searching on internet, I found some performance charts of the Merlin Engine BHP output: As you can see there is an increase in BHP,(mainting a constant Boost Setting), until reaching the critical ...
0
votes
0answers
63 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 ...
2
votes
1answer
95 views

Why is the RPM limit on a Lycoming IO-540 different in the -C and -D versions?

On a Lycoming IO-540, it seems there is a Max RPM difference between the -C and -D versions (and thus a max HP difference too). Does anybody know what is different in the engines that causes this, or ...
1
vote
2answers
126 views

Do aircraft travel faster at higher altitudes?

I'm aware of the difference between TAS and IAS, and how IAS gets lower in reference to TAS as you climb and the air gets thinner. What I'm trying to figure out is whether or not an aircraft's IAS ...
6
votes
1answer
976 views

Why is the Auto GCAS system on F-16s limited to only 5G?

The automated ground collision avoidance system (Auto GCAS) on the F-16 is set up for only 5G's. If the system predicts an imminent collision, an autonomous avoidance maneuver—a roll to wings-level ...
1
vote
3answers
181 views

What is the rate of climb of an airliner to reach cruise altitude?

Data from this question's answer states 2300 kg of fuel is used for takeoff/climb and 2500 kg of fuel per hour is used at cruise altitude. Half hour idle descent burns 600 kg per hour (2% of total ...
-1
votes
1answer
70 views

If aircraft specific energy is a combination of kinetic and potential energy, why is altitude not a variable in the energy-maneuverability theory? [closed]

The Energy-Manueverability formula is $$ P_S = V \left( \frac{T - D}{W} \right) $$ with velocity $V$, thrust $T$, drag $D$ and weight $W$. $P_s$ represents specific energy, which is a combination of ...
1
vote
1answer
165 views

How does a headwind affect the distance that a modern passenger jet can glide?

If in an emergency and a modern passenger aircraft had to glide, will it make a big difference if the aircraft had a headwind rather than having to glide downwind to nearest airport?
2
votes
1answer
141 views

Could we use ground effect (over water) to increase an airliner's range? [duplicate]

Theoretically, would it be possible to increase the range of a modern jetliner in ground effect over the sea?
4
votes
1answer
465 views

When is Vmo/Mmo applicable?

I have read that for most planes Vmo (maximum operating speed) is the limitation below 25000ft and Mmo (maximum operating Mach number) is the limitation above 25000ft. Is it correct to say this and, ...
0
votes
2answers
129 views

How to anticipate the radius and rate of turn under specific conditions?

Given that an aircraft would normally start a turn from straight and level, how would one go about calculating the rate/radius of turn since there would be a delay before the aircraft can get to full ...
5
votes
3answers
167 views

Ground effect and Lift coefficient

Is there a correlation between the lift coefficient and the proximity between the wing and the ground? I know that the lift coefficient is dependent on angle of attack; However, based on experiments ...
2
votes
1answer
146 views

When the F 16 landing the flaperons are used for rolling due to the functionality as ailerons, but after touching the ground it is the same?

In landing gains the flaperons are down 20 degrees. If you have to do corrections of the bank angle on approach then you move upward only one of the flaperons. But after touching the runaway it is ...
2
votes
1answer
179 views

Need help with calculation of engine airflow and jet velocity and efficiency

This is an image of a set of questions that are relevant to an Airbus A380 type of aircraft (4 engines): As the answers are incorrect, I'd like to understand how these need to be calculated. Q1) I ...
1
vote
1answer
53 views

Equations for Computing Temperature and Air Density Ratios at Different Altitudes

When computing aircraft performance at different altitudes, two useful variables are the air density ratio (dr) and temperature (T). Using a ratio is helpful because you can recompute values, such as ...
14
votes
1answer
2k views

How much oil did Charles Lindbergh have to bring along to fly the Atlantic?

A study of the Wright Whirlwind 200 hp J5 made me wonder if it could be matched to a Cessna 172 airframe. Radials have the ability to run on much lower grade 50 octane gasoline and have great air-...
3
votes
0answers
72 views

Matching the Drag Equation to Real Airplane Data

I am trying to compute airplane performance for a piston-driven airplane with constant speed prop using the standard equations for Lift, Thrust and Drag. I have found that there are a couple of useful ...
0
votes
0answers
44 views

Under what engine conditions is glide performance typically determined in performance charts?

The performance section of an information manual I am using states that the glide range indicated is "power off". Does this terminology definitely imply that the engine is not firing? or ...
1
vote
2answers
132 views

Conflicting A320 Climb Profiles

In the Airbus brochure (more like a book) Getting to Grips with Aircraft Performance, the standard climb profile for the A320 family is mentioned as 250 kt / 300 kt / M0.78 With this accompanying ...
0
votes
0answers
18 views

How to calculate Longitudinal dynamic stability derivative for a wing? Mq and Mα

How to calculate Moment due to rate of change in pitch(Mq) and Moment due to rate of change in AOA(Mα) manually and How to extract from CFD software? Consider a fighter aircraft is in Case 1- Cruise ...
5
votes
1answer
134 views

What was the most efficient cruising altitude of the Lancaster bomber?

An earlier question concerning lower high altitude cruising fuel efficiency of the B-29 bombers with 4 x Wright R-3350 air-cooled radial Cyclone engines made me wonder about the Lancaster bomber, ...
1
vote
0answers
63 views

Model of aircraft banked turn

I'm trying to write a model of aircraft motion during a banked turn, so for say a 60Degree roll angle constant altitude turn will require 2g lift. However to achieve this lift the aircraft has to ...
2
votes
1answer
56 views

How does maneuver g-load affect drag?

High-performance jets can use high-g turns to scrub airspeed and energy (e.g., in run-and-break landing patterns). What is the relationship between the aggressiveness of a turn and the rate of ...
2
votes
0answers
62 views

Coefficient of Parasitic Drag - What is the Preferred Basis of Measurement?

In attempting to determine the coefficient of Parasitic (Zero Lift) Drag - the cD0 - for various aircraft, I have discovered that there appear to be several ways this number is represented: by ...
6
votes
3answers
710 views

Mathematical function in performance diagrams

I have taken upon myself to digitise some scanned old performance diagrams, e.g. roll distance as function of mass and OAT, TAS as function of power setting, etc. The obvious goal is to allow the ...
2
votes
1answer
239 views

Other than fighters, which airplanes can fly straight up?

I would think, for example, all modern fighter jets can maintain 90 degree climbs due to having thrust to weight ratio greater than one. Are there any other air planes which can do that?
1
vote
1answer
91 views

How to calculate your landing ground roll distance with this chart?

Under these conditions: Pressure altitude 5,000 ft, Headwind Calm, Temperature 101 F I have no idea how to even start
3
votes
1answer
143 views

How could Airbus better tailor the A380 to the modern market? [closed]

I understand any company do things that give net profit. But, had not manufacturing newer engines that increase its Endurance and Range saved it from its decline? Airbus had designed the A380 to ...
4
votes
1answer
74 views

Performance metrics of a propulsion system - optimising a propulsive fan system [closed]

I'm designing an electric fan propulsion system for a hybrid-electric business jet. The hybrid business jet uses a series hybrid configuration and distributed electric propulsion. The electric fan ...
1
vote
1answer
110 views

How much money can be saved by removing seats?

If have an airbus A380, and I remove 500 of the seats entirely from the airplane (Along with their overhead compartments), and the remaining 300 or so seats I fill up normally with people, is the MPG ...
1
vote
1answer
108 views

Why does the Information Manual say "C172S - Flaps 10 (Preferred) for Normal Takeoff", when the models before S-model do not have this note?

Do Flaps 10 really do anything performance-wise other than reducing ground roll and distance over a 50-foot obstacle? If not worried about clearing an obstacle, does a Flaps UP-normal takeoff make ...
7
votes
1answer
507 views

What is "alternate takeoff" in this PT6A performance table?

I am flight mechanic, and I would like to know about this performance limitation: What is the definition of alternate take off? Why is the alternate take off temperature limit (ITT) lower than max. ...
2
votes
1answer
355 views

What are variable stator vanes?

Most turbofans nowadays use "variable stator vanes"; what are these, what is their purpose, and how does it affect a gas turbine's performance?
0
votes
2answers
79 views

Why Lift-induced Thrust Required(Tr) decreases and Zero-Lift Tr increases with the increase of velocity? [duplicate]

As the minimum Tr is at the point where L/D (lift/drag) ratio is the most. And Lift-induced Tr depends on the Coefficient of Lift, (Cl)^2 and Dynamic Pressure (q) which also increases as velocity ...
4
votes
2answers
203 views

In this F-104 V-n diagram, why does the stall speed (in terms of IAS) decrease with altitude in some parts of the flight envelope?

(This question has been edited to reflect a change in perspective: based on answers to the related question What is causing these "corners" on this F-104 V-n diagram?, I now believe that the ...
8
votes
1answer
447 views

What is causing these "corners" on this F-104 V-n diagram?

In this V-n diagram for an F-104 (source: this Wikipedia link), on the left-hand edge of the flight envelope, what is causing the "corners" that we see at the following points? (Numbers are ...
0
votes
0answers
18 views

For a supersonic inlet, does an increase in Mach number lead to an increase in adverse pressure gradients?

For a supersonic inlet, does an increase in Mach number lead to an increase in adverse pressure gradients because of the shock waves(which leads to boundary layer separations) and decrease in inlet ...
0
votes
1answer
34 views

How do I calculate the centre of gravity on the lateral (transverse) y-axis?

I have a real issue with determining the centre of gravity for the y axis of an aircraft, especially with selecting the reference/datum point and how to measure the displacement. Please I would really ...
0
votes
1answer
75 views

Aircraft thrust calculation

I had a question regarding thrust calculation for an aircraft during cruise. For an aircraft flying at a constant cruise altitude and a constant Mach number (level unaccelerated flight), what exactly ...
3
votes
1answer
154 views

What happens to Vyse and Vxse above the OEI ceiling?

An EASA ATPL question/answer insists, counterintuitively, that a twin which loses an engine and must drift down will find its least rate of sink at Vxse. I've been trying to understand this, but haven'...
-1
votes
3answers
198 views

In which part of the flight does a plane reach maximum lift?

In which part of the flight does a plane reach maximum lift? My logic: I think a plane reach maximum lift in a horizontal flight, when a plane start rolling on a runway, landing gear produce more ...
-2
votes
2answers
122 views

Will my CRI CRI twin engine plane fly if I replace the engine with a single 15hp gasoline engine? [closed]

I'm using a lighter materials to rebuild plane, to cut down plane weight to 56kg and a 1.2m 3blades propeller.
8
votes
3answers
1k views

What effect does a direct crosswind have on takeoff performance?

Is the take-off distance increased by a direct crosswind?
1
vote
1answer
72 views

How does deploying flaps change the gradient and rate of descent?

My understanding is: Using the gradient formula "(T-D)/W x 100", we can see that with the deployment of flaps, the gradient would reduce (due to the drag added). And since Rate of Descent (...
0
votes
1answer
184 views

What is the fuel burn rate for climb of a C-130J Hercules?

I am trying to graph the payload range for a C-130J Hercules and I need an approximate value for fuel burn rate which I cannot seem to find online. Does anyone know approximately how much fuel a C-...
0
votes
0answers
52 views

Ceiling parameter Derivation

I read the absolute ceiling of an adequately powered airplane is determined by the formula, $\frac{W}{S} = \frac{1.4}{2} p M^2 CL$ Where, $W/S =$ Wing Loading $M =$ Mach Number $CL =$ Lift Coefficient ...
4
votes
2answers
2k views

Do manufactures list the maximum speed of an aircraft based on its theoretical maximum speed or dive speed?

I know that the absolute maximum velocity of an aircraft is based on the thrust available. However the aircraft is usually limited beforehand by other speed limits such as dive speed and Mach Never ...
0
votes
1answer
110 views

Descent of Light attack aircraft to loiter altitude

How do Light Attack Aircraft (LAA) such as the Embraer Super Tucano descend from their cruise altitude to their loiter altitude to be on-station above ground troops? I want to know the way these ...
0
votes
1answer
91 views

What thrust is used for thrust to weight ratio?

Performing some preliminary calculations for an aircraft design I have and was wondering what thrust I should use to calculate thrust to weight? The thrust calculations I have, vary due to speed (...

1
2 3 4 5
16