Skip to main content
56 votes
Accepted

Does a carbon fiber fuselage suffer wear from pressurization/depressurization?

Yes, it does. CFRP's fatigue manifests through multiple mechanisms. It usually begins with matrix cracks, causing a loss of bonding, and grows through delamination, i.e. loss of adhesion between the ...
Therac's user avatar
  • 27k
51 votes

Why are there no helicopters with the rotor mounted on the bottom?

If the rotor would be underneath the helicopter, then: The helicopter body would still generate vertical drag from being exposed to the vertical airflow, but now above the rotor, The rotor would work ...
DeltaLima's user avatar
  • 83.5k
45 votes
Accepted

Is there a common name for ailerons, elevators and rudder?

Primary control surfaces is the typical name for ailerons, elevators, rudders, etc. Auxiliary flight controls include things like flaps, slats, slots, spoilers, leading edge devices, etc. Secondary ...
Wyatt's user avatar
  • 2,135
37 votes

Why don't Airbus planes have perfectly smooth front sections?

It is not about Boeing versus Airbus, but rather about old versus new. Your representative image for Airbus is an A320, whose technological competitor by Boeing is the 777. Juxtaposing the two, we ...
Aditya Sharma's user avatar
36 votes

Why are there no helicopters with the rotor mounted on the bottom?

Actually, there are/were (nearly/sort-of) Have a look at: Lackner HZ-1 Aerocycle on Wiki
MikeB's user avatar
  • 779
36 votes
Accepted

What is this little "rod" thing on the back of the F-22 for?

According to this cutaway (source) it is a "runaway emergency arrest hook housing":
sophit's user avatar
  • 12k
26 votes
Accepted

What does Line imply in Line Replaceable Unit?

"Line" refers to "Air Line" or "Flight Line". It's the same "line" as when you refer to "line operations" or, for pilots, "line indoctrination&...
John K's user avatar
  • 131k
26 votes
Accepted

How can a passenger have opened an emergency exit on an Airbus A321 in flight?

According to the FlightGlobal article you linked, the L3 door was opened (the emergency door behind the wing on the left side). All 8 doors on the A321ceo are plug type doors that cannot be opened ...
Bianfable's user avatar
  • 55.9k
26 votes
Accepted

Is there an aerodynamic reason for airship fins to be at the tail?

Yes. With fins in the middle the airship would be impossible to control. In order to work, fins need a lever arm with respect to the center of gravity. The longer, the better. Almost all air vehicles ...
Peter Kämpf's user avatar
23 votes

Do fighter jets have windshield wipers?

No modern US fighter jets are equipped with windshield wipers. At faster speeds they aren't needed as moderate rain simply blows off. Heavy rain at slower approach speeds will sometimes present a ...
Michael Hall's user avatar
  • 26.1k
22 votes

Why don't Airbus planes have perfectly smooth front sections?

The pinched-nose airplane has its (flat) frontmost windshield panels almost touching and raked back, which forces the vertical crease. The corresponding panels on the other airplane are farther apart, ...
Camille Goudeseune's user avatar
21 votes

Why isn't the rudder below the tail?

It is bad to put things below the tail because they might hit the ground. Even with nothing below the tail sometimes there is still a tail strike. http://avherald.com/h?article=42b2d053
Anonymous Physicist's user avatar
19 votes

Why do most light aircraft not have AoA indicators?

Historical inertia, mainly. AoA indicators aren't too terribly expensive to install anymore, but they were until very recently. We are now in a period where AoA indicators are fairly inexpensive and ...
Chris's user avatar
  • 15.6k
18 votes

Visually see flap settings from passenger window behind wing

Yes, you can definitely tell how much the flaps are deployed just by looking at the numbers on the flap itself, close to the root of the wing, which gives the angle in degrees (original picture): I'...
sophit's user avatar
  • 12k
16 votes

Is the DC-6 Supercharged? And what is a Turbosupercharger?

Yes, the DC-6 is supercharged with mechanically driven centrifugal superchargers. A “turbosupercharger” is another name for “turbocharger” which is an exhaust driven centrifugal supercharger. The DC-...
Mike Sowsun's user avatar
  • 37.8k
16 votes

Why are there no helicopters with the rotor mounted on the bottom?

Some AAVs have the rotors mounted outboard and mostly below the cabin. Whether that's a 'helicopter' or not is arguable. Some definitions specify overhead rotor(s). So it seems more practical when ...
Spehro Pefhany's user avatar
16 votes

Why isn't the rudder below the tail?

The MQ-1 Predator does have a V-tail ruddervator below the tail. Does the Predator drone's design make a tail strike more likely on takeoff and landing? The MQ-1 is already at high risk of a rear ...
Anonymous Physicist's user avatar
15 votes

What is this little "rod" thing on the back of the F-22 for?

It is the tailhook housing. Looking for a definitive picture, but can't find one.
WPNSGuy's user avatar
  • 8,904
14 votes

Why do most light aircraft not have AoA indicators?

One reason is just that it is hard to build as a console instrument for light aircraft. Just having an indicator on the side is easy, but having it show up in instrument cluster requires measuring an ...
GremlinWranger's user avatar
14 votes
Accepted

Location on the wing where obstacles least disturb airflow

Generally, the farther aft a small obstacle is, the less turbulence and drag it makes, because farther aft the boundary layer is more likely to be already turbulent. However, if the obstacle is heavy, ...
Camille Goudeseune's user avatar
12 votes

How can a passenger have opened an emergency exit on an Airbus A321 in flight?

CNN reported that the passenger "opened the door when the aircraft was about 700 feet (213 meters) above the ground and about two to three minutes from landing in the city 150 miles (240 ...
abelenky's user avatar
  • 30.7k
12 votes

Is there a common name for ailerons, elevators and rudder?

All of the aileron, rudder, and elevator surfaces may be considered "aerodynamic control surfaces." This would also cover the primary, secondary, and auxiliary control surfaces, as noted by ...
cessnao3's user avatar
  • 121
12 votes
Accepted

Why does the F/A-18 have so many lift supplementing devices?

The leading edge strake extension is there to solve a handling qualities problem the airframe had at high angle of attack without it. Not only does the aircraft need to fly at high speeds (which ...
Rob McDonald's user avatar
  • 11.9k
12 votes

Do fighter jets have windshield wipers?

Fighters or other airplanes without special provisions like boundary layer blowers or wiper systems, that fly in rain a lot, can/will apply water-beading coatings like "Rain-X" or an ...
John K's user avatar
  • 131k
11 votes

What are the effects of having the aileron hinge line on the pressure side vs the suction side of a wing?

Here's one thing large endurance aircraft can do: they use spoilerons instead of ailerons and rudders. You simply leave off the downward pointing off-side aileron, which creates adverse yaw. The ...
Robert DiGiovanni's user avatar
11 votes
Accepted

Why does the trailing edge have a more pronounced taper than the leading edge on the Cessna 172?

That's just the natural taper you get when the spar is straight in plan view, and the spar depth and airfoil is shrinking as it gets to the tip.. The chord is constant out to the strut attachment so ...
John K's user avatar
  • 131k
11 votes

Why isn't the rudder below the tail?

Why isn't the rudder below the tail? Compromises, as usual in the aerospace world. From an aerodynamic and flight mechanics point of view the best location for the vertical tailplane would be ...
sophit's user avatar
  • 12k
11 votes

Are accident reviews comprehensive enough?

Yes, they are very comprehensive. As officially stated, reports do provide details about the accident, analysis of the factual data, conclusions and the probable cause of the accident, and the related ...
Therac's user avatar
  • 27k
11 votes

Why aren’t flaperons seen on many aircraft?

Usually a simple solution is best. Complexity adds weight, cost, maintenance, failure modes, certification challenge, etc. In aviation, we should always strive for the most simple solution possible -...
Rob McDonald's user avatar
  • 11.9k
10 votes

Why does the F/A-18 have so many lift supplementing devices?

The F/A-18 Hornet was designed to take off and land on an aircraft carrier. It also needed a very high maximum speed. To fly very slow (to land on the deck) and very fast, different aircraft shapes ...
Anonymous Physicist's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible