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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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Super critical aerofoil advantages [on hold]

Advantages of Supercritical aerofoil?
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2answers
164 views

What is the correct abnormal procedure in case of vertical stabilizer failure?

What is the correct abnormal procedure in case of vertical stabilizer failure in cruise? Am I correct in guessing that one should descend to a lower altitude and decrease speed?
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3answers
210 views

How can I compute the minimum possible bank angle for a turn with a given radius?

I know that I can find an upper bound for the bank angle for a plane, if I know the maximum sustained load factor of that plane because the roll angle and the load factor $n_z$ in a turn are directly ...
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1answer
3k views

What role did the RAT (Ram Air Turbine) play on US Airways flight 1549?

An article in June 2018 Flying Magazine regarding the RAT by a Rob Mark explains that Capt. Sullunberger deployed the RAT for additional power to guide the plane down to the safe ditching on the ...
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1answer
135 views

How can I calculate the fuel required for a specific route and aircraft?

Okay, I'm writing a online game. I've got two airports and the equipment. For example: Heathrow - LAX on a 744. What I want to work out is the fuel required, as this will apply a cost to the airline. ...
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91 views
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1answer
80 views

Where can I find information on the DC-9's turn radius in flight?

Does anyone know where I can find information on a DC-9-30's turn radius at various altitudes and airspeeds? I've tried Googling it, but all I've found is information about its turn radius while ...
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2answers
102 views

Is c.g rear or fore of wing leading edge?

This video states that the c.g of most non tapered airplane is 25%-30% of wing chord REAR of the leading edge.The aerodynamic center(a.c) of most wing is 25% rear of the leading edge ....Does this ...
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114 views

Boeing 757-200 Fuel Burn

So up front, I'm aware of the high number of aircraft and environmental factors and how oversimplified my request is. After all, there is a reason that the aircraft manufacturers provide charts to ...
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2answers
300 views

Would putting several small propellers on a wing be efficient?

I saw this video that NASA posted, which presents the idea of putting several small propellers on a wing: They claim that by doing this you can force air to blow over the wing more quickly. This ...
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0answers
141 views

Will leaving the ducting on the propellers attached to a DIY aircraft give it more thrust? [duplicate]

I'm not sure if its the right place, I have a problem with a flying thingy, and you like flying thingies, don't you? I will be trying to add some means of propulsion to my friend's styrofoam plane (...
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1answer
175 views

What is the bank angle that should be sustained to move in a uniform circular motion? [duplicate]

I want to deduce the rate of turn of targets that move in a uniform circular motion. The radius of the different circles are known in advance. I have searched for my question and found the following ...
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2answers
123 views

Can lift be equated to how much air is moved?

The explanation for lift that I find easiest to visualize is that air is deflected downward by the wing. This downward action causes an equal and opposite reaction of an upward force against the plane,...
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0answers
149 views

What airspeed is required for a Hercules C-130J to do a loop?

Last Wednesday a Lockheed Martin LM-100J performed a loop at the world-famous Farnborough Air Show. This is was so impressive! I wonder what kind of airspeed is required for this kind of stunt?
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1answer
327 views

Is 1 propeller always more efficient than 2?

Based on other answers I've read here (1) (2) (3), a single large blade propeller is the most efficient type of thrust you can get. There are 2 reasons for this (as I understand it). Firstly, ...
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2answers
130 views

Are high lift wings bad for faster speeds

I notice a trend in many aircraft designs. If the aircraft was designed to go slowly but have shorter takeoffs/landings they use airfoils with a high lift. However for long endurance flights they use ...
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1answer
75 views

What does “E” stand for in a polar curve?

In the following polar curve, there is a symbol "E" with the number 33.5 next to it. What does this mean?
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1answer
152 views

In a jet, are Vy and Vx achieved at a constant AOA at all altitudes?

It is known that in terms of IAS, Vx (best climb angle speed) rises with altitude, and Vy (best climb rate speed) decreases with altitude, until they converge at the plane's absolute ceiling. http://...
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2answers
116 views

Why do some multi-engine aircraft have accelerate-go distance in their performance charts and some don’t?

I'm curious about why some airplanes have accelerate-stop distance (ASD) and accelerate-go distance (AGD) in their performance charts and some don’t include that. Does anyone know why?
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1answer
199 views

What procedures are in place at London City Airport for emergencies after V1?

Given the challenging operating environment at EGLC, what procedures are in place for emergencies after V1. Is it possible to return to the airport?
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3answers
336 views

Why was Energy Maneuverability theory not applied to the F-14?

In John Boyd's (declassified) 1966 Energy Maneuverability [PDF] report, studies were done on the F-4 and on the MiG-21 and those studies were applied to the F-15, F-16 and F-18. My questions: Why ...
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2answers
265 views

What is the difference between centripetal and centrifugal force?

In a homework problem I was asked: In a balanced banked turn an increase in angle of attack will :? Answers are : 1/ reduce indused drag. 2/ increase centripetal force . 3/ increase centrifugal ...
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5answers
249 views

Is wing sweep needed on supersonic aircraft?

Area rule states that bodies with the same crossectional area distribution have the same drag. Does that mean I could use a straight wing on mach 1.2 aircraft with performance as high as sweep winged ...
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0answers
40 views

What’s the steepest possible descent for big commercial jets? [duplicate]

What’s the highest descent rate, an A320/737/A380/younameit can achieve in safe controlled flight and how do they achieve it? E.g. can those jets do side slips to have a steep approach angle (maybe ...
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0answers
88 views

Is there a fixed ratio between highest L/D and max endurance L/D?

It can be demonstrated that, for any airplane, there is a fixed ratio between the maximum range and maximum endurance speeds (1.31607...). Does another, fixed ratio exist between highest L/D and L/D ...
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1answer
180 views

What is the stalling speed of a Cessna 172SP at an altitude of 2000 feet?

What is the stalling speed of the Cessna 172SP if the temperature is +11 degrees Celsius, the power is off, the CG is at the forward limit, the flaps are at 0 degrees and the altitude is 2000 feet?
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47 views

How many meters to take off and land on the sea for the Canadair CL-415?

The French version of the wikipedia article about Shinmaywa US-2 claims that this amphibious seaplane take off and land from and on water quite shortly : À masse maximale de décollage l'aéronef s'...
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1answer
359 views

How to calculate required thrust for take-off knowing gross weight and L/D?

I know that many variables play into the required thrust for a take-off and for climb. Most of those specs boil down to a targeted gross weight, wing loading and L/D ratio. Intended flying speed range ...
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1answer
104 views

How much speed is required to achieve lift on something that weighs 1000lbs? [closed]

I was wondering how much speed would be needed to get an object that weighs about 1000 pounds to generate enough lift to get off the ground and achieve flight?
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1answer
270 views

What causes this much engine damage?

EASA and FAA have placed a 300hr inspection AD on select Dreamliner Trent 1000 engines after multiple failures. Here is a photo of an AirNZ engine. https://leehamnews.com/2018/04/14/faa-ad-may-...
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1answer
90 views

How much does weight really affect the operation cost?

Hi given an information from a reliable new source article (https://www.nytimes.com/2008/06/11/business/worldbusiness/11iht-air.1.13628276.html), it was mentioned that "Every 25 pounds we remove, we ...
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1answer
93 views

What are the main factors that make an aircraft have good STOL performance?

What are some of the main characteristics and design principles utilized to make an aircraft have good STOL performance? As a bonus, what are some disadvantages to some of those characteristics and ...
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3answers
190 views

Will this simple equation (pic attached) produce a rough estimate of the top speed of a prop driven aircraft?

Calculating the approximate top speed of a vehicle is straightforward. $v = \sqrt[3]{\frac{2P}{c \cdot D \cdot A}}$ where v = velocity of the vehicle P = power of the engine c = coefficient of ...
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1answer
111 views

Does the parking brake provide additional deceleration in an abnormal situation?

During a rejected takeoff at a speed > V1, you obviously try to stop with all available means since a runway overrun is a very undesirable result. In this case, could using the parking brake in ...
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2answers
325 views

Why is V1 based only on using brakes?

V1 is the speed that an aircraft may abort a takeoff so long as the airspeed is below it, or is committed to flight if it is over that speed. V1 calculations are based only on the brakes (not sure ...
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1answer
134 views

Why is the thrust/drag increase much lower at a lower FL with weight the only variable?

From and related to: What is the relation between drag and weight? Friction drag is not affected by the angle of attack change. The [induced] drag will increase with the square of the mass ...
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4answers
183 views

Is it possible to determine the approximate climb rate of an aircraft knowing its top speed, engine power and weight?

Is it possible to determine the initial climb rate of a craft with a few key pieces of data such as top speed, engine power and weight? For example the XB-42 was an experimental bomber design from ...
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1answer
347 views

Are the vortex generators on the Cessna Caravan necessary and sufficient for safety of flight?

I've been doing some reading about the C208B (Cessna Caravan) in prep for my new job flying cargo; I came across this article which (as far as I can tell) is a transcription of litigation surrounding ...
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3answers
84 views

Does the speed of the air molecules matter in aircraft performance?

Does the fact that air molecules move slower in cold weather and faster in hot weather also affect the aircraft's performance or no? So if its cold there is a higher chance or air molecules hitting ...
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1answer
460 views

How an Engine thrust changes with airspeed? Why?

I'm interested in how the thrust of a turbofan engine is affected at higher airspeeds (TAS). I know (I believed) that engine thrust(at constant N1) was relatively constant like in the following graph (...
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2answers
212 views

What should be the minimum time spent in cruise (for e.g. a B737)?

Having a short sector to fly, it would not be convenient to climb all the way up to the best cruise altitude, since the time in climb would burn more fuel than that necessary for a flight at lower ...
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4answers
364 views

Why is there a relationship between maneuvering speed and weight? [duplicate]

Could you explain the relationship between maneuvering speed and weight? Why are they linked?
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1answer
316 views

What makes the left engine on a conventional twin-engine aircraft the critical one?

I already know that this is because of P-factor. But I don't know how to draw a picture or explain this simply?
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0answers
142 views

Why is a weight and balance graph lozenge-shaped?

(fireair.co.uk) Why is a weight and balance graph lozenge-shaped? I have tried to find the answer but it seems to be really hard to find. Why is it not a square?
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1answer
256 views

Can aircraft depart/arrive after another aircraft has sprayed snow on the runway?

Does snow spray affect runway surface friction? The weather was bitterly cold on March 18th, 2018 and Birmingham airport was covered with snow. As you can see in this video, an A380 sprays snow on the ...
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1answer
77 views

Need some help with a seemingly simple question [duplicate]

An aircraft flies from A to B, distance 155 nm, in 1 hour and 23 minutes. If there is a tailwind of 12 kts the TAS is?
2
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1answer
99 views

How does an increase in climb rate affect climb gradient?

I'm learning to take (and pass I hope ;)) my PPL exam and I've just found one question, that I'm not 100% sure about. How is climb gradient going to change (for small angles) while rate of climb ...
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1answer
562 views

Why is the landing distance increased on grass runways?

Checking the Cessna 152 POH it says to increase takeoff distance by 15% of ground roll (makes sense due to increased friction). Also says to increase landing distance by 45% (doesn't seem to make ...
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1answer
5k views

How could this weird shaped aircraft Airbus Beluga fly only with two engines and use short runways?

More than that! She could land and take off fully loaded on 2000 meters of runway at Hawarden Airport as seen here in this video. At my local airport the runway is 2500 meters long and an Airbus A300 ...
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What is the mathematical relation between Vstall and Vloiter?

I need to know this relation in order to know the loiter speed of my aircraft!