xxavier
  • Member for 5 years, 6 months
  • Last seen this week
  • Madrid, España
Is lift in fact a kind of drag?
55 votes

An 'aerodynamic force' (just one force...) appears when a body is immersed in a fluid stream. By convention, two components are chosen, one of them parallel to the stream direction, called 'drag', and ...

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Why do planes fly at a high angle of attack when flying slow?
37 votes

Lift is (among other things) a function of the airspeed and the angle of attack of the wing. Hence, if you reduce your speed, you have to compensate the associated lift loss by increasing the angle of ...

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What is the smallest manned aircraft with four engines?
Accepted answer
27 votes

The Short Scion Senior flying boat was powered by four 88 hp radial engines and its weight, empty, was 3,650 lb (1,637 kg).

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Would it be feasible to build a jet fighter plane based on a wooden construction?
24 votes

The wings and a few parts of the body of the Heinkel He 162 jet fighter were made of plywood. https://de.wikipedia.org/wiki/Heinkel_He_162#Konstruktion_und_Ausr.C3.BCstung The Bachem Ba 349 'Natter', ...

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Does lift equal weight in a climb?
23 votes

In an aircraft that is climbing at a constant vertical velocity, the total of the upward-directed vertical forces is the same as the total of the downward-directed vertical forces. Were it not so, ...

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Why are there different number of propeller blades on the inboard and outboard engines?
Accepted answer
18 votes

The inboard engines were of a different type, and more powerful than the outboard engines. Hence, the props had to absorb different power, so they were four-bladed for the inboard and two-bladed for ...

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Which commercial aircraft can stay in the air the longest?
18 votes

A commercial airship, like the 'Zeppelin NT' can stay airborne for 24 hours. The record (for a military US-Navy blimp in the 1950s) is 264 hours, 12 min. It covered more than 13,000 km. Record ...

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Why do pilots slowly give the plane more thrust during takeoff?
17 votes

High-powered single prop planes may react violently if the throttle is opened abruptly. Torque reaction and P-factor should be smoothly dealt with...

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Can a passenger drone perform auto-rotation?
17 votes

That drone has fixed-pitch rotors, and that pitch is optimized for thrust, not for autorotation. In the absence of power, those rotors won't autorotate. They will stop rotating 'in the right way' and ...

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Can anyone identify the plane in this old photo?
16 votes

It's probably a Stinson Junior. Built in the late 1920s and early 1930s.

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How does speed affect lift?
14 votes

The lift equation is $$L = \frac{1}{2} C_L · v^2 · S · \rho$$ where $S$ is wing area, $C_L$ coefficient of lift, $\rho$ air density, and $v$ airspeed. Using units of measure $\text{m}^2$ for $S$, $\...

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What is this vintage small airplane with low wings and twin propeller engines?
Accepted answer
14 votes

It's a LET L-200 Morava, a Czech plane... http://www.aviastar.org/air/czech/let_l-200.php

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Would a helicopter with the blades on the bottom fly the same, if at all?
14 votes

One of the first helicopters that really flew (c. 1918) was the 'Petróczy-Kármán-Žurovec', intended to be used by the Austro-Hungarian Army as a tethered observation platform. The observer stood above ...

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Why can't we extract more from exhaust gases in gas turbines?
14 votes

It can be done, but the better specific fuel consumption does not compensate for the extra weight. We all know that aero engines have to be as light as possible. In land, stationary installations, ...

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Is there a place where altitude while flying is negative?
13 votes

There are several regions where you could (at least in theory) fly below sea level. For example, in the Dead Sea depression, that is the lowest stretch of land on the planet, reaching a maximum depth ...

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Can an ultralight aircraft fly with a 18hp engine?
13 votes

It's possible to arrive at a rough estimate by assuming that the L/D ratio is 9. Now, the empty mass is 70 kg. Let's add 45 kg for the engine, transmission and propeller. And we must not forget the ...

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Is possible to stick two '2-blade' propellers to get multi-blade propeller?
12 votes

It's done sometimes, for ultralight aircraft and paramotors. Like this:

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An airplane has an engine that pushes its flight. What force pushes a glider to fly?
11 votes

The force that pushes a glider is a component of its weight. More precisely, it's the projection of the vector weight W on the glide path. It's exactly of the same value of drag D, if the glider is ...

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Throughout aviation history, what airships were metal clad?
Accepted answer
11 votes

At least two all-metal airships are known to have existed, the first one invented by David Schwarz, and test-flown in Tempelhof, in 1897. It flew, but crashed when landing. Another one, a really ...

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How fast were propeller planes during landing on aircraft carriers during WW2?
11 votes

The stall speed of the F4U Corsair may be 89mph, and a safe approach speed might be 95-100mph, but that's airspeed... Measured with reference to the carrier deck, you have to substract 20mph headwind (...

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What is this strange structure, of a type often seen by pilots in hilly regions?
Accepted answer
10 votes

It's a reflector for microwave links, a passive repeater. More info here (article in Spanish): http://notascordobesas.blogspot.com/2015/01/el-repetidor-pasivo-de-microondas.html

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What aircraft model is on this old photograph?
10 votes

It's a Carden-Baynes Bee... A British plane built in the 30s... https://en.wikipedia.org/wiki/Carden-Baynes_Bee

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What type of helicopter is shown in Star Wars The Last Jedi featurette?
10 votes

Googling the registration EI-ILS: Eurocopter EC135 T2 Irish Helicopters Ltd MAX. PASSENGERS 6 YEAR OF PRODUCTION 2008 HOMEBASE EIDW (DUB), Dublin Intl

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Would it take 7 to 10 times more energy to lift a turbofan-helicopter?
10 votes

Helicopter rotors are very large precisely for that reason. Lift from a rotor (or thrust from a propeller or fan) is obtained by accelerating a given mass of air m to a velocity v. The thrust obtained ...

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What is the purpose of the glazed round area atop the Ju 87 Stuka G?
10 votes

I think it's a transparent cover for a direction-finding loop antenna. The rear gunner doubled as navigator, and probably needed to check the position of the moveable loop antenna. Ref.: Luftfahrt ...

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Can the energy dissipated in a power-off descent be calculated and expressed in horsepower?
9 votes

That power is sink rate x glider weight. If you use m/s for sink rate and newton for weight, you'll get the power in watt. Advantages of SI... It's easy to understand why it is so. Within a uniform ...

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Is is possible to have an aircraft launched from a submarine or directly from under the water?
9 votes

The Japanese navy did that in WW2. https://en.wikipedia.org/wiki/I-400-class_submarine

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What is the 0-60mph time of an aircraft carrier catapult?
Accepted answer
9 votes

According to Wikipedia https://en.wikipedia.org/wiki/Aircraft_catapult an American carrier type Kitty Hawk has a catapult capable of accelerating a mass of 35000 kg to 139 knots (71,51 m/s), and the ...

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What is the typical angle of attack aircraft fly at and at what angle of attack do they stall?
9 votes

It depends basically on the wing section. Some of them stall at a higher angle of attack than others... To quote typical values (for wing + body, since not only the wing gives lift...) a given plane ...

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Has anyone burned hydrogen in a gas turbine?
8 votes

Von Ohain's first prototype of his HeS 3 turbojet, the HeS 1, burned hydrogen in the first runs. Only after some modifications was he able to make it work with a liquid fuel. https://en.wikipedia.org/...

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