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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2
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5answers
146 views

Is (L/D)max achieved at a specific speed or AOA?

I'm little bit confused about the (L/D)max. So I've read this blog: https://joeclarksblog.com/?p=4155 and the author shows this graph: So if I understand it ...
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3answers
514 views

Would a Chinook helicopter fly better with contra-rotating along with counter-rotating propellers?

Would a Chinook perform better or have any advantage with dual contra-rotating propellers over a Chinook with just normal counter-rotating propellers?
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1answer
86 views

Do takeoff (or other) performance calculations for jet aircraft take into account the type of fuel being used?

Jet aircraft can use any of a number of different fuels:1 Jet A-1 is a straight kerosene, not that much different from what you used to buy for committing arson fuelling portable space heaters. JP-8 ...
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1answer
81 views

What does the “test result indicator” indicate on a cockpit voice recorder?

I am really curious as to what the “green/red” strip of led indicate and the numbers below it. Having read around the web, i speculated that it could be an audio quality rating scale. Would help alot ...
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1answer
2k views

Is the location of an aircraft spoiler really that vital?

I was wondering that spoilers in most of the aircraft are always placed aft (towards the tail) the CG location. Why aren't they placed ahead of the wings or near the nose of the aircraft? The same is ...
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1answer
124 views

What is the average time and distance needed to reach cruising height?

I am trying to compare trains with airplanes and the distances where taking a train is more viable than an airplane. I guess this would depend on the type of plane, but the Airbus 320 seems like a ...
6
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2answers
324 views

What makes the Antonov An-2 have no stall speed?

The Antonov An-2 is notable for being able to fly at a very low speed. However, what confuses me is that it has no stall speed: The An-2 has no stall speed, a fact which is quoted in the operating ...
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1answer
4k views

How long did the SR-71 take to get to cruising altitude?

How long did it take for the SR-71 to go from taking off to 80,000 ft, including refueling?
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1answer
70 views

What is the effect of aileron deflection on the centre of pressure?

Deflecting an aileron will increase or decrease the camber of the outer wing where the aileron is attached. I learnt on this platform that centre of pressure (c.p.) moves fore and aft with aileron ...
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1answer
108 views

How does landing gear affect thrust on a light twin-engine airplane?

I'm working on my commercial multiengine rating. And I got this question from my examiner, and I answered: landing gear produces penalty drag, so it decreases thrust. But the examiner says this isn'...
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2answers
1k views

The Mig 21 and the Mirage III have been criticized for lack of range, is this a limitation of the wing configuration?

Mig 21 Range: 1,470 km (910 mi; 790 nmi) at 10,000 m (32,800 ft) with 2 × K-13A missiles and 800 l (180 imp gal; 210 US gal) (Wikipeda) J-7 Combat radius: 850 km (459 nmi, 528 mi) (air superiority, ...
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3answers
297 views

Why are Vertical tails generally tapered?

I'm just intrigued to know why the vertical tail of a majority of aircraft is tapered? Is it due to aerodynamics, structural design or due to some instrumentation or multiple other reasons?
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2answers
161 views

Are modern commercial airliners flyable without operational computer systems?

Do modern commercial airliners have manual control capability to fly and land if electric power remains on but all computer systems and digital communication/guidance fails?
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1answer
56 views

Propeller effect on the L/D of an aircraft (Pusher Propeller configuration)

I recently performed an aerodynamic analysis of a fixed-wing UAV with a pusher propeller configuration. I found out that the L/D reduced by about 15% when compared to the body alone without propeller. ...
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1answer
84 views

Best Glide with Flaps T/O in DA20-A1

The Diamond Katana DA20-A1 Manual says that the best glide angle can be achieved with flaps in the t/o position at 72kn at maximum weight. My naive understanding would be that a flaps up position ...
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1answer
383 views

Could this helicopter's body be a flying wing?

This question: Could a helicopter fly like a plane this way? asks if a helicopter can turn sideways using additional wings to tip forward to allow the rotor blades to act as a propeller. The tail-...
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1answer
73 views

How is maximum rate of climb defined in aircraft specifications?

In common aircraft specifications a "rate of climb", or "maximum rate of climb" is specified. For example the wikipedia page for a Spitfire, or C172. However my intuition is that the rate of climb ...
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1answer
109 views

What will be the performance penalties of increasing the wing area of a delta winged aircraft to obtain a lower approach speed?

Delta winged aircraft such as the Dassault Mirage III have an approach speed of 170 knots as specified by the manufacturer. The Mirage F1 was designed to have a lower take off and landing speed than ...
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1answer
241 views

Do all airplanes have the same turning radius when operating under the same conditions regardless of size and weight?

Would any airplane in coordinated, turning, level flight have the same turn radius at a given combination of no-wind ground speed, bank angle, and density altitude as another airplane of significant ...
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1answer
221 views

Why was the Graf Zeppelin's endurance when fully fuelled with both fuels less than the sum of its endurances with each fuel separately?

The LZ-127 Graf Zeppelin used a unique dual-fuel system, with both a gasoline tank and a set of gas cells filled with blau gas; the airship could be flown using either fuel or both. The purpose of ...
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2answers
707 views

Would this be a dangerous impeller to use for a drone?

I am considering using a 3D printer to make unconventional impellers for a custom-made drone that I am planning to build. I am concerned that these plastic impellers may explode if their motors' RPMs ...
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0answers
47 views

How are the weights of sumo wrestlers shown on the load&trimsheet form? [duplicate]

Under normal circumstances most airlines use standard weights to calculate passenger weights. Sometimes, passenger groups with different weight than the normal passenger profile can also travel. How ...
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1answer
60 views

Do aircraft performance figures include corrections for areas with especially strong or weak gravity?

The strength of gravity at the Earth's surface is not constant, but varies from place to place by as much as a few percent: (Image by NASA.) As a result, an identically-loaded aircraft weighs less ...
5
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1answer
191 views

What is “Carson cruise” and can I determine it myself?

Mike Y. just posted an answer containing the following: With today’s fuel costs, the Carson cruise angle of attack, which represents the most efficient way to fly fast with the least increase in ...
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2answers
203 views

What ISA temperature to use in the density altitude calculation?

In the density altitude formula: DA = PA + [120 x (OAT - ISA Temp.)], should one use the ISA temperature at the field elevation or the ISA temperature at the pressure altitude?
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0answers
56 views

What could cause a lower manifold pressure at full power after an annual?

I recently completed the annual on my E33 Bonanza. I notice on takeoff at full power that the MAP is about 1" less pressure than it was in the past at my home airport. It is also about 1.5" less ...
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3answers
140 views

How can I best prepare for my first lesson on stalls? [closed]

I am a flight student preparing to practice stalls and stall recovery in a Tecnam P-2002. I have already done spin recovery. On top of that, what preparation techniques have others found useful?
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0answers
59 views

What is 737-8 cg range

How does the Boeing 737MAX-8 CG range in percent mac compare with other Boeing airplanes? Forward cg is more stable but more difficult to control. Does the FAA require a certain cg range? Adding the "...
5
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1answer
277 views

How are elliptical winglets better than blended winglets?

I've read in few papers that elliptical winglets give better performance than blended in terms of their L/D ratio. I am not able to find why elliptical winglets are better. the two differ by their ...
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1answer
185 views

Which helicopter can auto rotate the farthest? [closed]

Could the rotors be modified to perform better at auto rotating and maybe less at powered performance?
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2answers
415 views

How to calculate the glide distance?

Can somebody please explain how I go about this problem? A Cessna 172S is flying at 9842.52 ft from the ground and the engines stop producing power. If the aircraft is in a glide configuration and ...
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0answers
39 views

Bird strikes and engine protection [duplicate]

I am just wondering why the creators of aircraft cannot come up with some sort of high utility screens to mitigate bird.srikes. Thank you!
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0answers
102 views

Why is the F-16's service ceiling 50,000ft? [duplicate]

What defines the service ceiling for aircraft, in particular the F-16? I suppose, as with almost everything, this depends on the aircraft, the engine type, etc. While I'm fine with a comprehensive ...
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1answer
209 views

Is overall pressure ratio same as compressor pressure ratio for a gas turbine engine?

For a typical gas turbine engine, turbofan in particular, is the compressor pressure ratio same as the overall pressure ratio? For modelling purposes can we use the same value of overall pressure ...
0
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1answer
365 views

Why is Boeing being blamed for the recent 737 Max crashes? [closed]

Boeing has received more than 5,000 orders for the aircraft, it has delivered 350 so far and only 2 of them have crashed. That's not a very high crash rate. The FAA, until just a day ago, was very ...
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0answers
43 views

Can high G aircraft handle extreme turbulent weather?

Can aircraft that can handle high G forces, such as military or aerobatic aircraft, enter extreme weather like thunderstorms or lenticular clouds without structural damage?
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1answer
133 views

How energy efficient is an aircraft take off?

How much work is generally done by an aircraft (e.g. B737NG) in order to reach V_rotate, and how does this compare to the energy content of the fuel that is used?
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2answers
384 views

Does altitude influence the flight range of an engine driven aircraft?

I'm reading a chapter about flight performance during the cruise phase and the influence of altitude. My book (Aerodynamica, prestatieleer en vliegtuigtechniek by Bas Vrijhof on page 155, written in ...
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2answers
297 views

Why do the B747 of NASA Shuttle Carrier Aircrafts (SCAs) need additional vertical stabilizer?

Here is picture of B747 SCA of NASA and the AN-225 SCA. There are additional vertical stabilizer in the tip of the elevator to the Boeing's, while the AN-225 is designed with the vertical stabilizer ...
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2answers
91 views

Which one is more effective produce power of this two turbine's location?

Consider we have the exactly same turbine which is possible to be mounted to the tail (left picture) and to the wing (right picture) as picture below. Which one will produce more power to the airplane?...
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1answer
88 views

Does heavy air pollution improve takeoff performance?

As you all probably know by now, aircraft have much better takeoff performance when and where the air is denser; this is why flights need to either use longer runways or jettison passengers and cargo ...
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1answer
154 views

Air flow over an airfoil

We know that in real viscous flow, boundary layer exists around the airfoil and there will be a separation point which flow starts to separate from the back of the airfoil( velocity gradient equal ...
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3answers
482 views

For how long after the last A380 delivery does Airbus have to provide spare parts for it?

After Airbus's announcement that they plan to discontinue A380 production in 2021 after the last orders are filled, how long will they have to guarantee the availability of A380 spare parts?
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2answers
217 views

Would this hybrid impeller design create enough thrust for a VTOL aircraft?

I am wondering if combining a centrifugal blower impeller with an Archimedes screw impeller would create a hybrid impeller that would create enough thrust to lift up a VTOL aircraft. Please reference ...
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6answers
2k views

What is Density Altitude?

I'm trying to get a deep understanding of the term: Density Altitude. So I have read the explanations in my instruction book, and online articles. One source explained it differently then the other ...
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1answer
254 views

Since when had fighter jet designer stopped caring about Whitcomb's Area Rule?

According to this source, designers of military fighter jets seemed to have stopped centering their design on Whitcomb's Area Rule for quite a while. Yet even the twin series fighters struggle to ...
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4answers
96 views

Would a propeller extracting air from a cylinder with holes in it be an ideal lift apparatus for a VTOL aircraft?

I am wondering if enough lift can be created for a VTOL aircraft using a propeller that is extracting air from a cylinder which is closed at one end and has holes in the top half of the cylinder. ...
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1answer
602 views

What's the difference of Vs from Vs0 or Vs1?

Vs: Stall speed or minimum steady flight speed for which the aircraft is still controllable Vs0: Stall speed or minimum flight speed in landing configuration. Vs1: Stall speed or minimum ...
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1answer
1k views

Why is the A330neo more efficient than the A350 on shorter routes?

For A330neo Wikipedia page, is written: A330neo enables profitability on shorter ranges where the longer-range A350 and Boeing 787 aren't optimized. For what reasons it is true? A330 and A350 ...
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1answer
82 views

What is a simple way to explain why best range airspeed is below normal cruise airspeed? [closed]

Without using complex mathematics, please explain why best range airspeed is less than normal cruise airspeed.