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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1answer
136 views

How do I calculate the correct rotation speed for a given density altitude?

The Airlines calculate the rotation speed of every takeoff based off the weight given to them from their operations people and also the density altitude conditions. In General Aviation we don't ...
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0answers
85 views

Could anyone provide me with the performance charts for Boeing KC-135R Stratotanker?

I am looking for the Long Range Cruise Maximum Operating Altitude performance against the weight of the plane, all engines operating. Would be grateful if someone could point me the way.
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2answers
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Is V best endurance configuration the best way to save a heavily overloaded aircraft?

After reading this, we all agree "the experienced pilot takes over, lowers the nose, and the plane is saved". Not bad advice, but what speed offers the greatest amount of excess thrust ...
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Plot Turn Chart in CAS with acceleration performance [closed]

I want to plot Turn Chart and the ft-Ma chart for the pilots with CAS. I have given the data in TAS. For example my specific excess Power has the unit m/s At first i calculate the TAS into CAS. Can I ...
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45 views

What is the meaning of "Contra-Rotating Propeller Increases Efficiency"? How is it calculated?

This picture is taken from here. In that video is mentioned that contra-rotating propeller increases efficiency up to 6-16%. Regardless of the number that could be vary from one airplane to another, ...
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3answers
672 views

Can prop wash from a live engine contribute a sideways force on the aircraft?

A recent response to this question, it was posited in the accepted answer that: the rudder "also creates a side force" (as well as a torque) that is countered by banking the aircraft, ...
4
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1answer
173 views

Can a jet-engine aircraft fly all the way to its service ceiling at its maximum takeoff weight? [closed]

I am trying to understand how high an aircraft can get to at its maximum takeoff weight (minus whatever fuel is consumed in getting to that altitude). Can it make it all the way to its service ceiling?...
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3answers
193 views

Could catalytic combustion improve the efficiency of jet engines?

Catalytic converters have come into common use with the millions of automobiles on the road these days, greatly reducing their emissions of unburnt fuel and NOx. Because the converter is outside the ...
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1answer
238 views

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 ...
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1answer
129 views

Why do you have to turn off the prop sync when changing the engine rpm? [closed]

I understand how prop sync works, I just don't understand why you have to have to turn it off to switch the rpm. Is there something that I am missing?
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2answers
4k views

Why does a Boeing 747-8 take more runway length to take off, compared to an Airbus A380?

The Airbus A380 is the largest passenger airliner. That also includes the Boeing 747-8. Meaning, the Boeing 747-8 is smaller than the Airbus A380. As far as I know, smaller planes use less runway ...
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1answer
83 views

Air Pollution and High Pass engines [closed]

If Air is use. “High Bypass Turbines”. Where does air pollution come in that is mentioned frequently by Politicians and media I’m a total layman at this
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2answers
182 views

Airplane accidents that happen during take off and landing [closed]

I have just seen some documentary about Munich Air Disaster in 1958. I found that the real reason behind this disaster is related to the aircraft performance with the thick snow runway during take off....
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1answer
379 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 ...
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4answers
3k views

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.
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76 views

Why do F15 air intakes move up and down? [duplicate]

I see it during startup. What is the propose of this?
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3answers
347 views

What is the difference between "cruise" and "en-route"?

I have a little misunderstanding about the two concepts: Cruise and En-route. Could you guys help me to compare the similarities and differences between these two concepts, maybe in some aspect like ...
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2answers
466 views

What's the optimal zoom climb angle for a fighter jet to reach its highest possible altitude in a parabola?

If a supersonic fighter jet wanted to reach the highest possible apogee it could in a parabola, what's the optimal pitch angle to do so? A too high pitch may result in insufficient thrust and a sooner ...
3
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1answer
167 views

Will a jet flown on a parabolic arc reach its highest altitude on a warm day or a cold one?

In level flight, on cold days jet-powered planes can fly higher because the air is denser. However, at the same time the true airspeed is lower because of the denser air. At warmer temperatures a ...
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1answer
42 views

Does the optimum LRC speed increase or decrease as the GW of the aircraft decreases during a long range flight?

I do not know what defines the optimum LRC speed for each aircraft, aeronautically speaking. I suspect it has something to do with optimum AoA but even then I am not sure if the LRC speed should ...
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102 views

Why they don't refuel A-340 airliners in flight? [duplicate]

The A-340 by Airbus was cancelled for ultra-long flying time operations, because fuel load at takeoff had to be enormous, limiting payload, putting it below the costs threshold. I copy this text from ...
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2answers
156 views

why do Lycoming piston engine aircraft operate at 75% best power? [closed]

What happens to the remaining 25%, is the remaining 25% lost due to friction?
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1answer
207 views

What is the name of the profession that makes RTOW charts?

What is the name of the profession an aerodrome operator would need if they wanted to make an aerodrome RTOW (Regulatory Takeoff Weight) chart for a specific aircraft? I've researched and found some ...
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692 views

Why does the optimum cruise altitude depend on the weight of the airplane?

In this answer, Bianfable notes: [O]ptimum cruise altitude for a 777-200LR at a weight of 340 t is only FL285, but after burning 100 t of fuel it has increased to FL360 Why is that? Is it simply ...
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1answer
86 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 ...
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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 ...
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1answer
109 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 ...
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2answers
137 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 ...
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1answer
1k 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 ...
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3answers
243 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 ...
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1answer
73 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 ...
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1answer
271 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?
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1answer
150 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?
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1answer
631 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, ...
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2answers
152 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 ...
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3answers
213 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 ...
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1answer
162 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 ...
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1answer
215 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 ...
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1answer
84 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 ...
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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-...
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78 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 ...
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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 ...
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2answers
228 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 ...
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19 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 ...
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1answer
163 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, ...
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0answers
64 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 ...
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1answer
70 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 ...
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0answers
67 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 ...
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3answers
717 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 ...

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