New answers tagged

3

Short answer: yes. Control effectiveness: We do care about ailerons The fact that there is an aileron at the wingtip implies that flow separation (stall) at the wingtip results in significant decrease or complete loss of aileron effectiveness during a tip stall. As a result, as you imply by your question, designing aircraft to begin their stall at the wing ...


2

Two points appear relevant here. First, all aircraft designers have exactly the same laws of physics to work against, and the same rules of materials science to work with, and those considerations also define the design of the engines used to power their aircraft. This means that an Airbus is going to closely resemble a Boeing that was designed for the same ...


1

Conventional gear is the term that includes both tail-wheel and tail-dragger, because there may only be a simple skid in place of the tailwheel. It is simple to construct, lighter and lower cost for a given strength than tricycle. Tricycle or nose-wheel gear. The main gear is very similar to conventional main gear it is just moved slightly behind the center ...


22

There are several reasons to have the pressure sensors in the front section of the fuselage. The further aft the more turbulent the airflow is and the thicker the boundary layer caused by the fuselage. This would cause strong fluctuations of the measured pressure and the reading could be inaccurate. Far forward the boundary layer is the thinnest because the ...


7

The boundary layer grows in thickness as you move aft on a fuselage. It is thinnest near the nose. A pitot tube near the nose only has to protrude a small distance away from the fuselage skin in order to extend out of the boundary layer and into undisturbed air.


3

This C-5 cutaway indicates it's a "Heat Exchanger Inlet (76)" or "Ground Cooling Fan (78)" EDIT: Upon closer inspection of this higher-res image, it may be the intake for the Ground Cooling Fan.


3

Notwithstanding the case that Quiet Flyer mentioned, generally no, because aerodynamic forms are inherently beautiful, so the need for dedicated stylists isn't there because an un-artistic designer striving for the best configuration will tend to produce an attractive shape by default (with exceptions of course, but overall). This tends to fit in with the ...


1

It depends on the aircraft. While not the norm, at least a few airplanes have been designed with input from "style" designers. At 4:58 on this FlightChannel video on You Tube about the Icon A5 amphibious lightsport airpane, we read that "the cockpit interior was designed by BMW designers, and the exterior was designed by Nissan designer ...


2

I was able to find this Panavia Tornado cutaway picture (took about 5 seconds): (Air International 1984-09 / P.Jackson - Tornado) Inside the left hand wing you can see a part labelled 197, with notation "Swivelling pylon control rod". This rod is tied to the main body of the plane, and while the wing changes its position, the rod pushes the ...


2

So, the probable exploitation was that the payload is rotated to keep it straight. However, at first, I haven't found any photo/info on google to support that explanation. But, I have found the answer to my own question. You can see the scratch marks generated by the movements of the racks (possibly pantograph) on the Panavia Tornado aircraft (for full size ...


4

Mechanically this can be done using the simplest form of pantograph, as a hinged parallelogram with one end fixed to the fuselage and the other to the ordnance pylon. Or, I suppose you could implement a digital one.


1

I think that this crevice which you have noticed is the hinge line for its aileron. This might not actually be an aileron hinge line, as later model B-52s don't actually have ailerons - if this is a later model B-52, then this may just be the remnants of what the ailerons once were. My answer is based upon this diagram of a B-52D.


12

They are Vortilons, a type of vortex generator. The placement of the vortilon low on the leading edge limits its vortex generation to high angles of attack (where the air meeting it is going over the top of the wing), and at low angles of attack, it's just a little fin sticking out, not creating too much drag (but not none). They are used to improve aileron ...


27

They are called vortilons. They can induce a vortex to the upper surface of the wing at high angles of attack, which allows flying at higher angles of attack before stalling. Additionally, four vortilons were installed on the lower surface leading edge of the outboard wing panel. Their interaction with the wing sidewash at high angles of attack produce ...


19

That is called a Survey Tail Boom and includes sensitive instruments that need to be mounted away from the aircraft body for clean measurements. You can see the name of the manufacturer LCAS printed on the boom. In this case, it seems to be a tail boom for magnetic field measurements installed on a Douglas DC-3, which is used for Survey according to Borek ...


2

Reciprocating engines are somewhat more efficient, but they don't scale up well. A larger piston engine can't have as large RPM, but that means weight grows much faster than power. That's not a problem for ships, where huge diesel engines are common, but it is a big problem for aircraft. On the other hand, turbines are very light for power even when large, ...


0

Fleet-wide fuel and parts standardization, and use of an approved and well-known powerplant; and the UAV is likely derived from a piloted vehicle which had been built around the turboprop.


1

Because of the air pressure at 26000ft the IC engine would have very little power without forced induction (turbocharger/supercharger) you then need boost control at lower altitudes to stop the engine exploding from cylinder pressure. You can't use a carburettor because you would get carb icing too, so it necessitates fuel injection. All these things make ...


4

Mostly reliability, and weight. A TP is far more reliable than a piston engine, and much lighter. The TP's lighter installed weight makes up some for its higher specific fuel consumption. You would use a piston engine to get operating costs as low as possible, and you're willing to live with lower reliability (you're forced to use turbocharging or ...


6

So how does the A320 design address this? Longer landing gear with attachment points further outward on the wing [...]? Yes, the A320 has a longer and therefore wider landing gear. You can find general aircraft dimensions in the Airplane Characteristics for Airport Planning documents. Airbus A320-200: 7.59m wide landing gear Boeing 737-800: 5.72m wide ...


35

When flying non-combat missions, many low-observability aircraft are fitted with radar reflectors. Here is a photo of an F-22 Raptor with a Radar Reflector fitted to it. That little tin can increases the RCS one hundred-fold! The role of the Radar Reflector is two-fold. For one thing, it makes the plane visible to other aircraft and to ground stations via ...


0

A stealth aircraft isn't actually invisible to radar. It's just harder for current radars to see stealthy aircraft at longer distances. This gives a stealthy aircraft the element of surprise against an enemy. So at a long-range a stealthy aircraft radar signature will be a lot smaller than a regular one perhaps the size of a small bird which will get ignored....


5

the "front-end nozzles" you mention are the air inlets for the plane's jet engines- one inlet per engine. The outlet that emits exhaust gases at great speed is in the rear of the engine. Some jets have only one engine, and one inlet. Some have two, some three, some four engines; the B-52 has eight engines and eight inlets. Greater numbers of ...


40

Like most military aircraft, the F-22 has a military equivalent of a transponder, an IFF system (Wikipedia): Identification, friend or foe (IFF) is a radar-based identification system designed for command and control. It uses a transponder that listens for an interrogation signal and then sends a response that identifies the broadcaster. It enables military ...


3

Circulation may be controlled via either air blown through spanwise slots or horizontal-axis rotors, alone or in combination. Experiments on wing systems go back at least as far as 1902 and since then almost every variation imaginable has been tried. The problems come in the engineering implementation. Where investigations have reached the stage of flight ...


1

It's because the center axis for the ellipses has to be along the thickest section of the wing, because there is also a taper in thickness that must be accommodated as the ribs get smaller and smaller toward the tip. In your sketch, the thickest section is at 40% of chord and the taper in both planform and thickness must be oriented to that 40% chord line, ...


1

Most light aircraft sit slightly nose-up in flight. This simplifies the design parameters for the wing mounting, as the wing needs to angle slightly up. The designer seeks to maximise thrust by angling the engine down so it points straight forward. On a high-wing type, angling the engine down also adjust the thrust line so it passes closer to the centre of ...


0

@knovics, you mean width as in fuselage diameter or include wings and engine mounting geometry too? Maybe this answer is at cross purposes to the question, but a long airplane can have advantages too . . it provides a greater 'moment-arm' for the rudder and this can actually help to control the yaw during engine failure. Such airplanes have much lower ...


3

In general, you can get good general dimensions from the Airplane Characteristics for Airport Planning documents (Boeing). These documents include the overall dimensions and everything relevant for the airport. This does not include the chord length though. To get more accurate dimensions, you can download CAD drawings from Boeing. I did this for the 747-400 ...


1

You might have heard of the "coffin corner" the U-2 pilots flew in. The U-2, at 90,000 feet, had only 9 knots between stall speed and Vmo. Airliners fly in a similar, but wider corner, with circa 15-30 knots between stall and Vmo. Vmo is where shockwaves start appearing on the upper wing surface, buffeting, engine surge and all kinds of bad stuff ...


1

As others have stated, tandem cockpits have advantages in that they create more slender bodies and require minimal modifications from single seat variants. The twin-seat modification is not always an issue, as many airplanes are designed from the get-go as two seaters, such as the F-4, F-14 and F-15. F-15 single and twin seaters share the same canopy, the ...


7

I think the idea "Cessna put bigger engines in the C-172 as bigger engines were certified" is a bit simplistic. Compare an early model Skyhawk to a late model - they have very different empty weights, which is reflective of how the basic design got heavier over time. Electric flaps, g-rated seats, seatbelts (and now airbags), more avionics, ...


18

Older planes were simpler and lighter, in part to make certification easier and in part to minimize the selling price and therefore maximize volume. Once that minimalist plane hits the market, though, customers invariably ask for things to be added, which nearly always means more weight. (Indeed, more weight itself is often the request, either payload or ...


2

In general, the smaller the engine the less challenging the initial development and the cheaper and sooner the new airframe will hit the marketplace. Early adopters provide valuable feedback, while the sales force soon get to know what extras the market is most desperate for. Meanwhile engines are also evolving and market expectations advancing. The designer ...


10

Increasing engine size allows improvements in performance. This can be used to open up new use models for the same or very similar airframe (putting 150HP in a piper cub, for example). It also supports practical use of seating capacity with full tanks in an existing airplane or safer operation at high & hot conditions or quicker climb outs, etc. All of ...


2

Generally, you are right. Reducing wing area is reducing overall drag. Within limits. Induced drag depends on speed and span loading. If the reduced wetted surface allows you to fly faster, reduced drag will be lower, leaving more of the power budget to overcome viscous drag. However, if wing span is reduced, induced drag will be higher at the same speed, so ...


23

The Cessna 172 first flew in 1955. The Continental IO-360 was FAA certified in 1962. The math is pretty simple. Yes, we (Americans, at least) are getting fatter, but that still doesn't allow for use of an engine that isn't yet certified. It's the same for GA as well as commercial aviation. Improvements in fuel efficiency and power tend to lead the ...


Top 50 recent answers are included