New answers tagged

0

The forward tilt of the main rotors with respect to the fuselage is not related to the tandem rotor design, but to a combination of fuselage lift and the need to also provide thrust with the main rotor. First off, a review of other tandem designs shows that those not related to the CH-47 do not always share the forward tilt: Bell XHSL-1 prototype Filper ...


-2

A rare double answer on this one. Very simple. Based on the principle of lifting any heavier than air object, such a table. Lift it at its center of gravity, it will not tip. Away from the center of gravity, it will lean towards the center of gravity, unless you apply downforce at the other end. The reason this concept works well for aircraft to explain ...


13

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 ...


18

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 ...


-3

I would start with slebetman's fine comment about indoor competition throwing models, which was my inspiration (Paper Airplane Guy record indoor throw) for delving into the theoretical why's of design, after having so many of my first paper airplane models pitch up crazily when I threw them hard. With the help of many threads and some practical experience ...


3

For propellers, there is a minimum ground clearance according to the EASA Easy Access Rules for Normal, Utility, Aerobatic and Commuter Category Aeroplanes (CS-23): CS 23.925 Propeller clearance Propeller clearances with the aeroplane at the most adverse combination of weight and centre of gravity and with the propeller in the most adverse pitch ...


4

Struts every which way, uncowled engines, wheels with fenders hanging out, wires, bits sticking out here, bits sticking out there, corrugated skins, fabric wings and tail... it's a mess; a flying Truss Bridge. There's just too much to try to quantify it like that. You could probably take a DC-3 and start adding all those things one at a time, and each item ...


0

In the case of biplane and a monoplane where all the wings involved have the same aspect ratio, the extra wingtips of the biplane should cause no loss of efficiency. On the other hand, interference between the top and bottom wings of the biplane will cause some loss of efficiency.


3

The Rutan Voyager (World Flight, 1986) two wings are not at the same position along the length of the aircraft. To save weight, their non-tapered spars are bolted together in the fuselage, so one wing is one spar thickness ahead of the other. With a wingspan of over 100 feet, it isn't very noticeable. It also has two vertical stabilizers but only the ...


0

The shape will be driven almost purely by functional concerns. How are those functional concerns tkane into account? It's not aircraft noses specifically, but the paper "Geometric Programming for Aircraft Design Optimization" explains how geometric programming, a form of convex optimization, can be used to efficiently extract optimal shapes and trade-off ...


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 ...


4

Based on this cabin layout of a Gulfstream G500 found on flexjet.com, I measured the aisle width at various places: The total width is given as 7' 11'' = 241.3cm. The aisle width at the marked positions is then: 63cm (2' 1'') 68cm (2' 3'') 44cm (1' 5'') 51cm (1' 8'') 46cm (1' 6'') 57cm (1' 10'') 50cm (1' 8'') This would give an average of 54cm (1' 9'') ...


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 ...


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 ...


0

Ok, first a sort-of-an-answer, and after that a solid whack on the back of your head: You propably are well aware of the crowdfunding scene: Kickstarter, Seedrs, Patreon etc. and you might be aware of how they work. I'd say they are your best bet on testing the lift coefficient of your project. Next option would be contacting local or global experimental ...


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) ...


3

Both the cyclic and the collective change the pitch angle of the main rotor blades. The cyclic is typically located in front of the pilot and is controlled with the right hand (presumably because most people are right handed), while the collective is controlled with the left hand. (image from Wikimedia, from Helicopter flight controls) The pitch angle of ...


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 ...


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 ...


4

No, aerodynamics study is not compulsory for building an aircraft, or parts of it. Some aircraft have been built by thousands of people, none of whom were asked for their diplomas. But if you want to legally fly what you've build, in USA airspace, then you must choose which category it falls into and what laws apply to it. https://www.eaa.org/eaa/aircraft-...


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 ...


0

Food for thought: perhaps the design of the Constellation's tail was inherited -- aesthetically if not engineering-wise-- from the Lockheed P-38 Lightning, where the position of the two vertical fins was selected to put them in the optimal position relative to the propwash from the two engines. Even on the P-38, it seems it might have been possible to ...


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, ...


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 ...


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. ...


3

The vertical tail of the A380 in the last photo is swept back. Surface sweep is used for high subsonic wings and tail surfaces, to postpone the effects pf compressibility when approaching the speed of sound. And when the vertical tail is swept back, the rudder hinge will be at an angle as well: the rudder chord will be a relatively constant percentage of the ...


0

Reduce the amount of the side sliping when jet bank. F16 have that.


1

Prototype only: the YF-12A. This was an A-12 derived fighter plane. The A-12 is better known for its other derivative, the SR-71 Blackbird. Both the A-12 and the SR-71 were intended for reconnaissance tasks, but the YF-12 would have been a fighter. With a first flight in 1963, it beats the Mig-25 by a year.


3

In any aircraft where the flaps produce lift the minimum speed will be achieved in a flaps down configuration.


0

Here is an explanation of a contra-rotating propeller, explained its advantage and disadvantage. 2 - Why contra rotating propellers? As explained, each blade of an airplane propeller is essentially a rotating wing. As a result, the propeller blades are like airfoils and produce forces that create the thrust to pull, or push, the airplane through the air. ...


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 ...


2

The reason to use ailerons as flaperons on delta wings is twofold: Delta wings reach maximum lift at a much higher angle of attack, which entails high pitch angle on landing, which is impractical. A way to generate enough lift at a reasonable angle is required. With low aspect ratio, space on the trailing edge is very limited, so there is a desire to use ...


1

Probably the MiG-25. Near as I know, it was the first to use the ‘four poster’ layout.


-1

Possibly might be the WW-2 era Me-262? I believe the prototype had twin tails.


8

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


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 ...


3

The load path is rotor blade to hub, to mast, to mast bearing set inside transmission, to transmission housing, to transmission mounts/struts, to airframe.


1

The force is transmitted through the mast bearing. Gearbox diagrams often omit that because they're already so complicated.


6

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


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. ...


3

Its for energy-maneuverability reasons. Like everything else in engineering its a trade off. 1st important fact to understand is this: In airliners, and most previous gen combat aircraft, designs are (primarily) made for flying in level (ie cruise) most effectively. At this optimal cruise point/line, the best engine fuel efficiency and aerodynamic efficiency,...


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) ...


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 ...


4

...how I can start autorotation with blades that have essential zero angular momentum... By using the collective pitch control mentioned in OP. At release, the blades should be aligned with the free stream like a feathering propeller, then gradually be set with decreasing blade AoA as the rotor speeds up. ...are there special considerations for the use ...


3

The term "3 point landing" is derived from old taildragger (3rd wheel in back) designs. In reality a 3 pointer is not desirable, as the wheel, front or back, being away from the center of gravity, can produce a nasty pitch if it bounces. At landing speeds this can be uncontrollable. The term "3 pointer" does imply good landing speed management, as the ...


1

You're after the landing gear oleo Source Control Drawings. You need to contact Cirrus' tech support and request the drawings from their engineering organization via their support organization, who may or may not want to help you, or may charge for them if they do. I expect they won't want to provide them because they'll suspect that it's for someone who ...


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 ...


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: ...


1

Normally the retrofitting path is from passenger service to freight service. In my experience, many freight operations already have the necessary airpacs, as certain cargo (zoo animals, livestock, biologicals and chemicals) may require environmental control. The cost comes in outfitting the aircraft for people, with the accouterments of modern air travel. ...


2

There is no technical obstacle to building tail mounted air brakes and APU. The Fokker 70 has a tail air brake, APU and also thrust reversers and spoilers as seen in this great photo from airliners.net: Fokker 70 landing in AMS


Top 50 recent answers are included