# Tag Info

## Hot answers tagged aircraft-design

38

Aesthetics are by far and away the last thing aircraft designers are optimising for. A better question might be, why do aerodynamically-efficient designs look pleasing, but that would likely be an art or psychology question and off-topic here. Since aircraft could travel at appreciable speeds, designs have focused primarily on drag reduction. Smooth curves ...

30

Surface 1 is a horizontal stabilizer with elevator, just the same as on any other aircraft with a T tail arrangement. Surface 2 is called a rear strake or a tail fin. There is one on each side of the fuselage. They provide extra stability during operation at high angles of attack when the fuselage is disturbing the airflow to the vertical tail. They are ...

26

The other way around - you set up the pilot for eye-to-HUD alignment. When you are in the right position then you can see all the data-fields on the HUD - if you can't see them, you move your seat.

25

It's mostly because of one of the most attractive things about aviation (shared with the marine world to a large degree). Form and function, aerodynamic necessity and aesthetics tend to coincide. Aerodynamically efficient shapes also tend to be the most artistically pleasing shapes. Airplanes that fly well tend to look good. Beyond that, you have the ...

21

Horsepower cannot be converted into thrust without knowing the speed at which this is done. In your case this is zero, so the special equation for static thrust applies. With $T$ for thrust, $P$ for power, $\rho$ for air density and $d_P$ and $\eta_P$ the propeller diameter and efficiency, respectively, this is T_0 = \sqrt[\LARGE{3\:}]{P^2\cdot\eta_{P}^2\...

21

To add to the other answer... The Pilatus PC-24 is billed as a business jet that can operate out of rough airfields. Comparing the pictures of the PC-24 to the Phenom 300 or CJ4, you can see that there is quite a bit of extra ground clearance. You can also see that the rear landing gear on the PC-24 are much more robust (dual wheels, longer travel length) ...

21

I have never heard of an ionization device being used on an aircraft, but when I searched Google for "Northrop B-2 ionization", I actually found a reference for this: Microwave frequencies emitted along the leading edge would readily ionize the approaching air and allow the B-2's high-voltage electric field to discharge a greater flux of positive ions. ...

20

You don't need to know much aerodynamics to build a plane if you follow plans for an existing design that somebody else has engineered and validated, and you don't make any modifications. If you are trying to design and build something new, even if superficially similar to existing aircraft, then yes you will need to study aerodynamics and other aspects of ...

19

A pilot will usually adjust his seat height to align his eyes roughly with the design eye-position in an aircraft. As there is almost no parallax error, even with the wrong seat height, HUD-elements will still align correctly with objects outside, however, some HUD-elements will be outside the projected field-of-view and not be visible to the pilot. The HUD ...

15

The huge support, or bulge, is a fairing, designed for reduction of wing root drag. So many people talk about wing tip vortex drag, but much more is created at the wing/fuselage interface, especially in uncoordinated flight. This improvement, first seen in 1930s vintage gliders (where else!), improves the airflow around the aircraft, resulting in ...

15

It's not compulsory as in there's no law requiring you to have studied aerodynamics in order to design an aircraft. It is however exceedingly hard to design an efficient and safe (and able to fly at all) aircraft without a thorough understanding of aerodynamics, so studying the field is a very good idea. What set the Wright brothers apart from many others ...

12

Complicated is a matter of opinion and I wont address that specifically since its somewhat subjective. But the core of the question is "why did the L-1049E have 3 tails" which is a legitimate question for this site. The design was to allow the aircraft to fit in hangars of the time A sleek fuselage, something like an elongated fish with smooth curves, ...

11

Their primary wing feathers have an unusual structure incorporating a fringed, comblike leading-edge, which reduces wind noise. The wing feathers also have an overall softness or flexibility. The trailing-edge of the wing is also dominated by soft, fringed edges. Even the underwing lining (covert) feathers have an unusual softness that plays a role in ...

10

One of the first was probably the unconventional XP-79. https://en.wikipedia.org/wiki/Northrop_XP-79 It never entered service of course, but does meet your criteria. Something that kinda meets your criteria would be the F7U Cutlass. Twin tails and twin rear mounted engines though the tails were in separate tail booms outboard of the engines, a similar ...

10

Firstly, it does not control the pitch of the helicopter, that can be achieved using the cyclic control. Secondly, it is named collective because it changes the pitch of of all the main rotor blades collectively, as in, at the same time and by the same amount. This is different from the cyclic control which adjusts the pitch of the blades as a function of ...

9

In addition to quiet flyer's excellent answer: Owls have large wings in relation to their body size and weight. One might think that no, their bodies are quite large, but actually owls are kind of flully flying feather balls: what you percieve as their bodies, is mostly air. This leads to two things: Low wing loading. Their large wings do not need to ...

8

They aren't holes they're flush screw heads.

7

As Jeffrey points out in his comment to the question: In flight, they are probably horizontal. When that plane is at cruise conditions, it will be in a very slightly nose-up pitch attitude. the thrust line from the props will then be in the direction of travel.

7

Thrust from a propeller aircraft will vary with airspeed, propeller efficiency, density altitude, etc. For a very rough guideline you can use 1 hp to equal approximately 3 lbs of thrust. So theoretically a 3,000 lb aircraft could hover if it had about 1,000 horsepower. The Lockheed XVF weighed approximately 15,000 lbs and could hover using about 5,000 hp. ...

7

Short answer: They're antenna(s) for the onboard VHF radio(s). Airplanes aren't actually required to have radios. But, if you want to fly into certain classes of airspace, you must have at least one VHF radio on board, to communicate with air traffic control. A lot of planes (in fact, I would say the majority of them) actually have two radios installed. ...

7

MCAS uses stabiliser input to retain full elevator authority in both directions for pilot input. MCAS is set up as an Inner Loop autopilot: it controls behaviour around the CoG of the aeroplane without displacing the cockpit flying controls. For aeroplane pitch control there are indeed two options: the stabiliser and the elevator. If the elevator is chosen ...

6

Go back to Estes rocket days. There is a whole class of competition rockets known as "heliroc" or helicopter recovery. These ascend like a conventional rocket, in a vertical(ish) path and fin stabilized; at (or near) apogee, they release a rotor by some means and the rotor spontaneously begins to autorotate, often giving a lower descent rate than a ...

6

No, it doesn't. Speculation about this was fueled by a Wikipedia circular citation.

6

The aerodynamic devices in question here were already present on MiG-29KUB which is a parent version of MiG-35: Wikipedia: MiG-35 The devices are in fact, as some have suggested, Krueger flaps, as Russian test pilot Pavel Vlasov describes in this article: The MiG-29KUB: in the Russian and Indian skies for 9 years "It is a modern multirole plane with ...

6

"Collective" is short for "Collective Pitch Control", which, you know, controls the pitch of the blades collectively. It's on the left side because the really fine motor control required of flying a helicopter with the cyclic is best suited to the right hand, and 90% of the population is right handed. A lot of machines (Hughes and others are exceptions) ...

5

The F-22 was developed in the 90's, primarily for use by the United States Air Force. This means it was designed to serve specific mission profiles. The F-35 however is going to replace the F-22 and serve all the air branches of the US Military. This means that it needed a broader mission profile. The last F-22 delivery was in 2016. For the F-22 Raptor: ...

5

I'm no expert on the plane, but wikipedia claims the Mig-21 has separate flaps and ailerons. On the trailing edge there are ailerons with an area of 1.18 m², and flaps with an area of 1.87 m². The common reasons for not combining flaps and ailerons are that it reduces aileron response and increases the chance of stalling the wing tip (which results in ...

4

No. 2 is a ventral strake and No. 3 is a canard. Neither have actuated control surfaces on the P.180. The ventral strakes are there to provide additional directional stability and the canards provide a more direct longitudinal balance and control, alleviating tailplane loads, and improving low speed handling. The Avanti was built for speed (400 KTAS in a ...

4

Why there so many pitch control surfaces on the Piaggio P180 Avanti? You mark 3 surfaces, but only one is movable, i.e. there is only one pitch control surface on the P180, not "so many". what is that device (number 2 in the picture), what is that name, and what is that for? Don't know the name myself, but it is there to guide the airflow around the ...

4

In order to hover in the air, you have to accelerate a mass of air downwards. Usually, this is done with a rotor, and the larger the rotor, the less the power you'd need to hover. The general expression (in theory...)for the power required, based upon momentum considerations, is: $P_{required}=T\sqrt{\frac{T}{2\rho\cdot A}}$ where T is the thrust (should ...

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