# Tag Info

28

No, they were not designed separately. They were designed by people who had all participated in collaborations before. The origin was the research into unstable configurations performed by MBB in Germany in the late 1970s by a modified F-104, the control configured vehicle F-104 CCV. F-104 CCV (picture source) As a result, MBB designed the Taktisches ...

18

Tailless means no horizontal tail, but a vertical tail is still allowed. Examples are the Convair F-102 or Convair B-58. Convair B-58 Hustler (picture source) Compare this to a flying wing: Here even the vertical tail is left off. Since a classic delta would have too little lever arm for yaw control, this requires a higher aspect ratio wing. An example is ...

17

It was obvious to the design team that conventional aircraft could not satisfy the required specification; knowing little about high-speed flight and unable to glean much from the Royal Aircraft Establishment or the US, the team at Avro investigated German Second World War swept wing research. The team estimated that an otherwise conventional aircraft, with ...

15

You ask the right question. Given the amount of misinformation out there, I can understand why you are confused. First the tip vortices: They are neither a source of downward force not do they cause drag. They are only a consequence of lift creation by wings of limited span. This answer tries to explain this in more detail. If, however, you mean the wake ...

13

Because it was something of a Burt Rutan trademark since his early days. His first designs, the VariViggen and VariEze, had such a wing already, and apparently he saw no reason to optimize the wing of the Starship. Rutan VariEze in flight (picture source) The only true innovation was a variable geometry canard, which he even patented. Being only 85% scale, ...

12

Every airplane is a compromise of conflicting demands. While I am not intimately familiar with the Mirage family, I can easily see why flaps were never included. In the early Fifties when work on deltas started at Dassault, the most important design parameter was top speed. High landing speeds were accepted, and given the design alternatives to a delta (...

11

Benefits of a delta wing: Due to the large root chord, a delta wing combines low relative wing thickness with a sufficiently thick wing spar for a lightweight structure. Since a low relative thickness keeps wave drag down (a drag component which occurs only in supersonic flow), this makes delta wings especially attractive for supersonic aircraft. The large ...

11

The wing design is different between F-16 and F-22 (which is similar to YF-23) because the requirements were different. The wing of F-22 (and that of F-23) were designed with stealth in mind, with the wing (and control surface) edges parallel to each other. There was no such design requirement in case of F16. F-16 is a highly maneuverable aircraft in its ...

10

Aspect ratio. Look at your two images: both wings offer the same wingspan, but the former requires a lot more wing area for it. Wing area is weight. More wingspan for less wing area means better fuel efficiency and thus better range. Poor aspect ratio, leading to excess induced drag, is a major disadvantage of delta wings. Much of modern stealth design is ...

8

The F-15 wingtip is a "raked" tip configuration, which increases lift and decreases drag.1 []2 This is the design decided by the USAF after discovery of several design deficiencies during initial flight test which included aeroelastic deficiencies (wing bending) and aerodynamic effects (buffeting). "In early June 1974, the Air Force flew the “raked” tip ...

8

I would not say that no other bomber ever had delta wings. Convair B-58 Hustler and Mirage IV both have delta wings. They are both supersonic though. The B-52 did not have to worry too much about MTOW and empty weight since SAC already had bases with long runways capable of really heavy aircraft. That's thanks to B-52's predecessor B-36. The B-36 was the ...

7

The effect of a horizontal tail can be built into a tailless aeroplane in two ways: By integrating into the wing profile: a horizontal s-shape with the trailing edge turned up. By combining positive sweep with negative twist.

7

1. Aeroelasticity Unlike a tailplane, a delta wing is more rigid due to its much bigger chord and multiple spars, so control reversal due to aeroelasticity isn't a special concern. Big subsonic jetliners typically lock the outer ailerons at high speeds. Concorde featured a similar function for the outer elevon, but only if $V_{MO}$ is exceeded by 25 knots as ...

6

No, not at all - there are at least two Delta Wing aircraft that feature a conventional tail, and they are the Gloster Javelin and the Mig 21 https://en.wikipedia.org/wiki/Gloster_Javelin https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-21 (Courtesy of http://airheadsfly.com/) In addition (and I believe this is within the spirit of what you've asked) ...

6

Your question is about friction drag while the text is mainly about aspect ratio. You seem to explain the choice of aspect ratio to be based on friction drag. This is not correct. Here and here are some good answers to explain the choice of aspect ratio. You will see that it has mostly to do with structural strength and wing volume to pack enough fuel. For ...

6

No, a higher sweep angle will reduce lift even more. All aerodynamic forces scale with the dynamic pressure, the product of air density and the square of airspeed, divided by half. If a wing doesn't produce lift, move to denser air or speed up. However, drag will also scale with dynamic pressure, and there is more which influences lift. One is the angle of ...

6

"Tested on a small free flight glider" gets a +1, but here some book knowledge helps. At lower Reynolds numbers, the classic airfoil shape looks good, but most lift comes from the bottom. This is why insects have flat wings and birds have delta tails and heavily undercambered wings. Flaps work very well on straight winged aircraft at higher Reynolds ...

5

The Gripen and Eurofighter are canards with a delta wing (as is the J-37 Viggen). This, coupled with relaxed stability, gives the first two unmatched maneuverability, and good transsonic and short-field performance. While the Viggen is a stable design, it too has very good short-field performance. The Mirage III (and the F-102, F-106, B-58, J-35 Draken and ...

5

The beauty of the pure delta configuration was you could get a reasonably low supersonic drag configuration in a planform with a lot of wing area, essential for really high altitude cruise and for reasonable landing speeds without high lift devices. It was a good overall compromise for Concorde's mission. The Avro Arrow, produced then scrapped in Canada ...

4

First, thank you for unearthing this unorthodox design! However, it shows that paper airplanes don't scale well. Nevertheless, it follows the same laws of physics, so the same equations should apply for a quick performance evaluation. What have we got? A flat plate airfoil. Maximum lift coefficient will be between 0.7 and 0.8, so minimum speed at a given ...

4

Concorde did not have any flaps or slats as mentioned here. This is due the fact that they don't have any tails, and wing trailing edge devices do the elevator and aileron jobs and they are called elevons.

4

Another answer that gives yet another factor for why it probably wasn't done: it's not necessary for delta wings. One of the limitations you have in exploring the flight envelope of delta wings is that you have no active control over a free-flight glider: you cannot alter the characteristics in flight. If you have experience with RC planes you will notice ...

3

The actual answer is straightforward. The F-15 wing was originally just a swept wing with a given taper ratio which resulted in a slightly swept trailing edge. The inboard portion was straightened just to simplify the flap. Because the flap hinge was now perpendicular to the fuselage the end of the flap was effectively sealed against the "booms" ...

3

I know this was answered a while back but let me give you my two cents. As explained by Peter a combination of the wing swept and low aspect ratio affect the lift production of the wing. But another effect also takes place; vortex lift. aeroalias explains it very nicely on this post: What is vortex lift? In short vortex lift is lift generated by the ...

3

No, for several reasons What you want is to compensate for the additional lift from downward deflected flaps at the back of a flying wing with vectored thrust. As @Sean points out this will not bring a noticeable net benefit if the lengthwise location of both forces is similar. But that is not all. Besides the force equilibrium around the flying wing you ...

3

A slender delta wing is a delta with low aspect ratio. The use I have seen is in the study of vortex lift, which is present at high angles of attack. What is vortex lift?

2

Delta vs conventional wing has a good answer on some of the benefits/drawbacks of the design. European military aircraft designers tend to prefer delta designs, dating back to the original Mirage, and even the Avro Vulcan bomber, whose design was actually begun in WW2. The other two major makers of military aircraft, the US and the USSR/Russia, don't tend ...

2

Because, although we often conceptualize Lift as all acting through the "center of Pressure" of the wing surface, this is a fiction, done only to aid in visualizing the total lift, and it's effects, and to aid in doing simple calculations that rely on this approximation. In actuality, Lift itself is an artificial abstraction, as it is just a portion of the ...

2

'Rest of the world' hasn't gone towards delta- only the previous generation European combat aircraft have (along with India). Also, none of the fifth generation aircraft have anything resembling delta wing. In fact, there are few 'pure' delta wings aircraft anymore- most of them are modified delta or have canards. Delta wings have a few disadvantages- the ...

2

Design is compromise Would a tailplane+flaps have avoided the risk of high-speed tire failures? Quite possibly, but tire failures can still happen and the debris will still hit the underwing where the fuel tanks are. The solution to that would be a swing wing, which was studied and rejected because of the added weight and complexity. Ground studies, backed ...

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