Gürkan Çetin
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7 answers
17 votes
7k views
Is it possible to accurately measure airspeed without pitot tube?
Accepted answer
17 votes

Technically speaking, inertial measurements are not sufficient to derive airspeed. You need pressure measurement (or airspeed measurement, see LIDAR). Pitot-static probes are the most usual and ...

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5 answers
5 votes
28k views
What is the highest possible thrust generated by 15cm ducted fan?
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9 votes

A 15 cm diameter fan could maybe lift 4 kg of mass with a tip speed of 0.6M. By increasing the power and the blade chord length (in other words, increasing the solidity of the rotor), this may be ...

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6 answers
34 votes
21k views
What simulation software do airlines use?
8 votes

Airliners train their pilots using flight training devices (simulators) to keep them current with their licenses. "Simulators" range from single PC applications for procedural training to Full ...

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4 answers
49 votes
8k views
Why do helicopters have such limited range?
6 votes

Basically, for the same gross mass, a rotorcraft requires considerably more power than a fixed-wing. This is due to the fact that fixed wing aircraft propulsion system needs to create thrust that is ...

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1 answers
2 votes
864 views
What are the following documents about aircraft maintenance?
5 votes

A service bulletin is a document that the manufacturer of an aircraft issues directly to operators of related aircraft. It mandates some maintenance / replacement / check activities. A rapid ...

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3 answers
14 votes
5k views
How do manufacturers engineer their aircraft to deal with tail strikes?
5 votes

Firstly, this article from Boeing explains how tail strikes occur. And this Boeing informational note gives more practical information on tail strikes and prevention: A short excerpt from that note: ...

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4 answers
11 votes
10k views
How are aircraft wings protected against flutter - aerodynamic oscillations that can break bridges?
4 votes

The discipline that deals with flutter and other air-structure interactions is called "aeroelasticity". Aeroelasticity analyses the dynamic modes of the structure taking into account the coupled ...

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5 answers
16 votes
11k views
Why do some fighters have two engines and other have only one but still give the same performance?
4 votes

Number and placement of engines is one of the initial trade-offs that a scratch-built aircraft design deals with. There are several criteria for the trade-off of the basic configuration. Here are a ...

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4 answers
5 votes
884 views
Is Fluid Structure Interaction considered in aircraft design?
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4 votes

deflections must be considered, if relevant in the force (pressure) distributions and if relevant for the aerodynamic and structural design of the aircraft. In addition to that, flutter, buffeting and ...

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1 answers
1 votes
365 views
What is the relation between hinge moment at the control surface and servo torque?
Accepted answer
3 votes

The servo torque depends on the mechanism. If it has a gear ratio of 1, they will be equal. If the servo is driving larger angular deflections than its own, the servo torque will be higher. Another ...

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1 answers
3 votes
493 views
What is the reference chord for AoA measurement or calculation in a twisted wing?
Accepted answer
3 votes

In short: it’s up to the designer to pick any definition as long as the design and analysis always obeys that definition. Usually, it’s a general practice to define a root chord and then calculate ...

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4 answers
12 votes
2k views
Can a small GA plane maintain level flight with a significant nose-down attitude?
3 votes

As long as the wing (the whole aircraft) has lift, theoretically, with higher speeds the pitch should go lower and lower. This means with full thrust, keeping the altitude constant, time will show ...

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3 answers
1 votes
784 views
Why would one wing stall before the other?
3 votes

In general, aircraft aerodynamics can be affected from manufacturing tolerances or consistent asymmetries. The reason can be due to any asymmetry in the wings or fuselage shapes, or wing-to-fuselage ...

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2 answers
5 votes
615 views
How many hours of test flight does a general aviation aircraft go through before delivery?
3 votes

All manufacturers have a quality system in place, and they also have a production baseline (which is a result of certification). so, as long as the quality system is utilized, there is technically no ...

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3 answers
6 votes
2k views
How does take off mass impact induced drag?
3 votes

Induced drag is caused by lift. (historically, Induced Drag was named "lift induced drag"). If weight(mass) of the aircraft decreases, the lift required to fly the aircraft decreases. And the drag ...

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8 answers
18 votes
14k views
How quickly can someone learn to fly?
3 votes

Regarding possibility to do it in 2-3 months time, yes a PPL is quite possible, but a Ground study before even the course starts will allow a much better experience. I'm an aerospace engineer, and ...

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1 answers
1 votes
3k views
Which airfoil would be optimum for a glider?
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2 votes

For a particular task of optimizing an airplane design for a specific point, you will need to consider the following characteristics, together with the endurance parameter: The pitching moment of the ...

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1 answers
4 votes
550 views
What does M mean in A400M Atlas?
Accepted answer
2 votes

Without the M, people would simply confuse the military cargo plane with the civil airliners that Airbus builds (e.g. A320, A380, etc).

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1 answers
2 votes
322 views
Lift and Drag Coefficients using load cell data
2 votes

I guess your design is a conventional one. One approach could be integrating two load cells in between the tail and wing sections. You can measure drag force and moment. And the moment may help you ...

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2 answers
2 votes
562 views
What is a minimal step angle deflection for flight control surfaces?
2 votes

There are several phenomena that may affect the asked resolution. The easier one is the static (steady case), and the dynamic case which requires several more analyses. Statically, the resolution of ...

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1 answers
3 votes
151 views
How do small unmanned fixed wing aircraft protect themselves against lightning strikes?
2 votes

You design your structure, as in larger aircraft, considering where the strike could potentially hit first, and where it would leave. The rest is electrically bonding everything together, and ...

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1 answers
3 votes
207 views
Beside payload size, what precise factors are considered to choose the fuselages shape?
2 votes

Assuming an engineering background, here’s a short list of factors affecting fuselage shape and size. aerodynamic considerations volume considerations structural and elastic considerations ...

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3 answers
3 votes
762 views
Why does ADS-B broadcast velocity?
2 votes

It sounds logical to have the velocity (speed) data in the ADS-B messages rather than computing it. One of the reasons is the computational cost on the receiver side. In order to calculate the speed ...

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2 answers
0 votes
827 views
How far should the two propellers on a twin engine plane be apart?
2 votes

For twin fuselage aircraft, the propeller distance is not the only parameter to look out for. Safety-wise, the distance of propellers affect the size of the vertical tail and rudder. Because, the ...

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2 answers
4 votes
247 views
How do UAV designers improve visual quality without compromising computational efficiency in mini UAVs?
2 votes

First, The low frequency dynamics that you mention probably comes from the movement of the aircraft, due to wind, gust, etc. one idea is to have a neutrally stable aircraft in pitching motion due to ...

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2 answers
4 votes
3k views
How are forces on the landing gear reduced or compensated for at touchdown?
2 votes

The second part of the question is simpler. Aircraft are designed to handle all operational loads (=limit loads) as defined in the FAR or other regulations. Plus they have reserve strength ...

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2 answers
7 votes
7k views
How is Maximum Take Off Weight determined?
2 votes

MTOW is defined and then verified by the manufacturer. During "verification", tests and other analyses are conducted to show compliance to all MTOW related requirements. For example, landing gear ...

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5 answers
12 votes
3k views
How do pilots maintain level flight after launching missile?
2 votes

The f-18 is a fly-by-wire aircraft. This means its automatic flight control system takes care of stabilizing the aircraft for cg changes, or other sudden forces (turbulence, bird strike, engine loss, ...

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4 answers
6 votes
9k views
How is engine thrust measured in flight?
2 votes

For simple platforms, load-cells can be attached in between the propulsion system and the airframe. This allows the propulsion force to be measured. This force data excludes aerodynamic integration ...

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2 answers
4 votes
245 views
How are performance variables accounted for when testing solar-powered aircraft?
2 votes

For large solar aircraft, it is advantageous to be flying above the clouds, for predictable and uninterrupted solar performance. There are flight test areas (airfields with a large-enough flight ...

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