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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Do symmetrical airfoils generate induced drag?

Cambered airfoils generate induced drag because they have a pressure differential between the upper and lower surface. However symmetrical airfoils don't. So does this mean that symmetrical airfoils ...
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9 votes
1 answer
1k views

Can TCAS and GPWS work at the same time?

A manoeuvre to avoid a collision with terrain, might put you onto a collision course with traffic above you. Can TCAS and (E)GPWS work at the same time? Are they coordinating?
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-5 votes
2 answers
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If you are in a terrain escape maneuver, would you be able to see traffic above you displayed in the cockpit of airliners [closed]

nayed If you are in a terrain escape maneuver, would you be able to see traffic above you in the cockpit of big airliners
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-2 votes
1 answer
149 views

Do airlines record the plane roll, yaw, pitch angles during a landing? (eg every 100 milliseconds)

We had a very wobbly landing in Washington DC today with United airlines. I was curious what the maximum roll angle (left right angle with ground) was during it. Other information that I'd find ...
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3 answers
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Which countries use qfe field pressure?

I heard that acrobatic flight, Russians, Americans use qfe but is it always the case? Also why doesn't everyone use it? Isn't qfe field pressure better than qnh local pressure... Does a pilot ever use ...
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0 votes
1 answer
62 views

If while landing ,a surface inversion occured close to the ground would atc or atis know?

A change in temperature, pressure and many factors might happen in a surface inversion.Thus affecting landing performance and calculation.The local peessure might change suddenly as well...
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1 vote
2 answers
129 views

CoG Envelope Calculation - Am I Doing Something Wrong?

I'm doing some pre-planning for a bush flight with the Icon A5, and I'm at CoG calculation. This is the W&B form from the A5's POH: I weigh 225 lbs. I'm simulating 111.6 lbs of gear which can be ...
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0 votes
1 answer
151 views

Ice Protection System for supersonic aircraft

How does a supersonic transport aircraft IPS system work? Does it work only for the engine nacelle or both engine and wing. I was thinking only for nacelle since the wings are usually highly swept. ...
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16 votes
1 answer
1k views

At what angle to the ground track does wind become favorable to lower fuel consumption?

We can all agree, flying from point A to B, a headwind will increase fuel consumption, and a tail wind will reduce it. The "jet stream" inspires these types of thoughts. Quartering headwind,...
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0 votes
0 answers
112 views

Does does turning into the wind increase airspeed and/or climb rate?

At 5:24 to 6:10 in the video linked below, Kelsey appears to be claiming that turning into the wind tends to create 1) an increase in airspeed and 2) and an increase in climb rate. Are either of ...
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3 votes
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UH1 fin under chin bubble

What is the purpose of the fin under the nose. It’s close to the co pilot side and starts at the bottom of the battery compartment and ends Near the bottom of the chin bubble. Wikipedia Photo
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0 votes
1 answer
103 views

How to calculate lift and drag of commerical aircraft in different phases of flight?

What is the best way to mathematically calculate values of lift and drag forces, in different phases of flight: takeoff, climb, cruise, descent, and approach? Edit: I have the idea of calculating the ...
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Is a yaw string better than an inclinometer in determining coordinated flight in a steep turn?

I feel obligated to go out and try this my self, but maybe someone has done this already and can help. The issue is that a centered "ball" position is affected by gravity more and more as ...
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1 vote
2 answers
140 views

What does deploying landing flaps do to the (L/D)max and minimum drag speed of an airplane?

I thought that deploying flaps will increase both the drag and lift, thus increasing L/D ratio? But do they increase proportionately? And how exactly does that correlate with the increase/decrease of ...
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1 vote
0 answers
79 views

Change of absolute ceiling with weight

Let's say an aircraft has an abs ceiling of some value at the start of its cruise and then it consumes some percentage of its fuel during cruise. How will this change the new abs ceiling at the end of ...
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2 votes
1 answer
197 views

Will this helicopter fly?

There is a helicopter that can lift 1000 kg. I'm going to suspend a very large 250 kg square piece of plywood underneath it, wider than the rotors. On the first try it will be attached directly to the ...
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3 votes
2 answers
318 views

how is ITT peak temperature affected by altitude during an airstart?

another T-6 Texan II (turboprop aircraft) question. When reading the airstart prodedure in the engine failure during flight section of the manual, I found something that Id appreciate the ...
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12 votes
2 answers
998 views

How does the weight affect the altitude that can be reached by trading speed after a total engine failure?

I recently read in the manual for The Beechcraft T-6 Texan II (a turboprop aircraft) about engine failure during flight at different altitudes and the gains from pitching up after the engine failure ...
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1 vote
1 answer
78 views

Extrapolating Oswald Efficiency Factor from CL^2 vs CD Graph

I have plotted this CL^2 vs CD graph for a glide test performed in a flight simulator. I want to find the Oswald Efficiency Factor, e from it and I assume I can do that from its gradient. With a wing ...
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2 votes
0 answers
116 views

Is there a difference from alignment with the fuselage between J79 and Spey engine versions used in the F4?

Is there a difference between the J79 and Spey engine versions used in the F4 Phantom in terms of alignment with the fuselage? It looks to me like the Spey nozzles are pointing downward.
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3 votes
4 answers
345 views

Can a plane still climb even if it has exceeded the critical AoA?

According to this answer here, an airplane requires less lift for a climb than horizontal flight because the thrust of the engines will point up. Now if the wing was in a stall condition, could the ...
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2 votes
2 answers
230 views

Will the electric motor work well in ultralight aircraft?

I'm trying to replace the 20hp gasoline engine in my ultralight aircraft (trike) to 10kw BLDC motor, asking to know if the 10kw BLDC motor will work Motor+battery weight, is less than the actual ...
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33 votes
1 answer
3k views

What is the operating altitude of jetliners?

I am performing a science project, and this involves knowing the average operating altitude at which commercial passenger airplanes (jetliners) fly. I am trying to find minimum operating altitudes and ...
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-1 votes
1 answer
243 views

Why does the aileron on this jetliner swing?

The picture I took here is left wing of a jetliner and it shows how the flap works during take off and landing. In that video is the inboard aileron, and it shows that the inboard aileron is not ...
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-3 votes
4 answers
221 views

How can ground speed be higher than airspeed? [duplicate]

I've heard that ground speed is higher than air speed when the plane is being pushed by wind wind. But how is this possible? Wouldn't your AirSpeed also increase since you're going faster?
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2 votes
2 answers
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At what bank angle does load factor's effect on performance increase?

I had this question on my Part 107 exam today. After some thought, I opted for a) 15 degrees, since that is the minimum bank angle at which the load begins to increase. Was I right? Load factors have ...
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3 votes
3 answers
308 views

What's a typical maximum acceleration of a turbofan-powered airliner taking off?

Whenever I fly on a turbofan-powered airliner, I always notice how much acceleration there is, which seems like more than any car I've ever owned could do. (That might be an illusion, I realize; ...
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1 answer
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Do critical angles of attack vary from plane to plane? Can a plane have higher or lower critical AoA than the other?

I have done a lot of research and I have found out that different planes have different climb angles. Some look like they are climbing at a higher rate than others. Why is this? Do some aircraft have ...
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0 votes
3 answers
160 views

Constant Speed Propeller [closed]

Dear All I know that this topic is not new, but I really tried to grasp the concept using available sources (which are actually pretty much the same). So, if possible (really appreciated): I'd ask ...
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What is the lift coefficient of the B767-400ER?

Can anyone tell me what is the lift coefficient of B767-400ER please? I have searched it in Boeing website and Delta Airlines website but still couldn't find the data of the aircraft performances. ...
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2 votes
1 answer
178 views

Why do transport-category aircraft have hard tailwind limitations?

With most transport-category aircraft, even with a 5 km runway, gross weight close to ZFW, using maximum flaps for takeoff, performing an unpressurized, full-power takeoff, the maximum legal tailwind ...
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3 votes
0 answers
180 views

What is the origin/history/background for performance categories A,B,C?

What is the thought process behind performance categories A,B and C? I know they were done based on MTOW 5700 kg, 9 pax and engine drive. I understand the table of classification, but I would like to ...
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1 vote
0 answers
94 views

How are IAS/CAS and TAS used in flight?

Could you please explain to me one moment in relation to IAS and TAS. In all books I read I see that the IAS is highlighted as a reference for stall, take-off, landing and other performance items. So, ...
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2 votes
0 answers
174 views

What is the Eurofighter's altitude record?

The Eurofighter Typhoon is a pretty nimble fighter jet, and many European countries use it in their military. Its service ceiling is 65,000 ft, but what is its current altitude record from a zoom ...
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8 votes
6 answers
3k views

Why is it that only prop planes have mixture?

Prop driven planes have mixture control yet jets don't. Why is this? Even turbine powered props like the SOCATA/Daher TBM have mixture control.
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1 vote
1 answer
92 views

The Effect of Pitching Moment on Aircraft Stability

I'm designing a small RC plane and I'm currently at the first iteration of airfoil selection. I have converged to Clark-Y, NACA-2412, NACA-2415, and S-8036. In comparing the four, I noticed that all ...
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3 votes
1 answer
222 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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2 votes
0 answers
99 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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3 votes
1 answer
220 views

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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0 votes
0 answers
54 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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4 votes
3 answers
719 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, ...
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4 votes
1 answer
190 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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4 votes
3 answers
237 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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4 votes
1 answer
273 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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3 votes
1 answer
144 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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8 votes
2 answers
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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-4 votes
1 answer
84 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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0 votes
2 answers
188 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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8 votes
1 answer
403 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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11 votes
4 answers
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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