Mr Parks and Mr Phillips

while I'm not Mr Parks or Mr Phillips, or any other form of expert, I seem to recall that Delta Wing airplanes have pretty bad lift to drag numbers relative to conventional wing planes (why I'm not sure...I hope others can explain further).

although the EuroFighter is a delta wing design so it can still be made effective.

 

While I'm not Chas or Mr. Parks or Mr. Phillips, I found this on wikipedia regarding military use of delta wing aircraft

"As the performance of jet engines grew, fighters with other planforms could perform as well as deltas, and do so while maneuvering much harder and at a wider range of altitudes."

 

One big problem was that they require an extreme angle of attack at low airspeeds, such as when landing. It was said that every landing in a B-58 was essentially an instrument landing because the nose was so high in the air that the pilot could not see anything out the windows.

 

I guess it depends if you consider only the American perspective, or also the European one.

As for fighters, or fighter-bombers, Dassault in France has had a very long flirtation with Delta configurations.

After the successful and combat-proven "Mirage III" of the sixties, which was, at least in its first generation, a "pure delta" without tailplanes or canards, Dassault reverted to the "standard configuration" (= with tailplanes) on the "Mirage F1" during the seventies. This was to avoid the main drawback of the "pure Delta", which is high induced drag causing very rapid bleed of energy in turns: the "Mirage III" was a very effective fighter at medium to high altitude, but not so at low altitude.

But in fact the "Mirage F1" was never considered fully satisfactory as a fighter, so they reverted back to a "pure delta" wing configuration for its successor, the "Mirage 2000" (well, if we do not take into account the two small vortex generators above the air intakes): the drawbacks of the delta having been compensated by electronic, fly by wire, controls and elaborate leading edge devices (slats).

As some of the late experiment on the aging "Mirage III" has shown in the meantime, canards were bringing an important amelioration in dogfighting capabilities, so the next aeroplane, the "Rafale", still has a Delta configuration but with canards, just as the Eurofighter.

The "Rafale" may be a thirty-years-old design, albeit pretty, but the Delta is still alive in our skies.

Rgds

 

While I'm not mr parks, phillips, woods, chas, or chad, Boeing's X32 entry in the Joint Strike Fighter was a delta wing design.

 

It has not ever been, nor is it, an abandoned design.

D-wings have their place / purpose as do conventional wings, and they each have different sets of pros / cons --- depends upon the desired performance characteristics and intended operational envelopes of the individual aircraft. It is a trade as to which will be the better optimized choice for a given design.

Currently, and traditionally, we have found conventional wings to be the correct choice for the majority of designs so more aircraft feature that configuration. But, D-wings still have a niche ---- and when the requirements call for it, it is always the best configuration.

 

Brian- For fighter aircraft, the main reason was very high drag at high angles of attack that lead to rapid energy bleed-off. At high AoAs, the delta wing design could also tend to blank both elevons and rudder, leading to a loss of lateral control. Often band-aided with strakes and other aerodynamic devices.

As mentioned, low speed handling characteristics were also not great, and the delta design, without a separate tailplane like the Mig-21, tended to complicate the fitting of high lift, high drag devices. As Convair discovered with the the XF-92, the delta wing also tends to be fairly high drag at even fairly low AoAs because of the large surface area of the wing. The resulting F-102 used area ruling (wasp waist) and wing conical camber to cut down on surface area problems and allow supersonic flight with the J57.

Designers basically just came up with more efficient wing designs. Eurofighter and Rafale, late 4th generation fighters, did stick with a delta wing design, with canards and very high thrust to weight ratios to make up for the aerodynamic deficiencies.

 

I'm not Mr. Parks, I'm ol' Bob. I'm not the duty expert on aerodynamics like some of the other Av-chatters in this forum but from what little I do know is that delta planforms don't fit all the objectives but they do have a place into which their performance does fit. I knew one pilot who flew the F-102 and he loved it. It seems obvious that the shortcomings of that planform in it's purest form have been addressed by modifying the section and breaking up the planform into different LE angles of sweep to control the vortexes over the wing at different AoA . The large amount of surface area adds to whetted area and drag. I don't think that it has been totally abandoned.

 

The old space shuttle was a delta, and I suspect that the new one will be too.

 

Shuttle wing I think would be called an ogival in its plan. Zat right?

 

James- On an RLV, you want all the drag and surface area you can get. At reentry speeds you are trading AoA against heating and bank angle against sink rate. Plus you have a reaction control system to control AoA, pitch, and bank until the atmosphere gets thick enough for the flight controls to work. Not exactly the same problem fighters have.

 

Yes, or some (like me, who do not know the word ogival) would say modified delta - the British Vulcan bomber also had a mild form of this in later versions to increase the efficiency in various modes of flight. But in reverse, it was more blunt at the roots and more raked at the wing tips. They actually built a manned flying model of that wing the size of a small fighter to test the configuration.

Also all true - I was just pointing out that the delta form still had a place in specialized purposes.

As long as I am up on this soap-box (I LIKE delta wings) - let us not forget the SR-71 Blackbird.

 

Don't forget the Concorde... ogival...

 

Yup - complete with the droop nose to handle the visibility problem during the high angle of attack on approach and landing.

 

You beat me to the punch....flew pretty well with a delta wing. I did read about why they decided on the delta for concorde.. of course im not smart enough to whip out the old slide rule and prove it to anyone, but the boys at Finton decided it was the only way to go....
doesn't hurt that its the best look plane ever built imho
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She was a beautiful bird..

 

The Vulcan wing started out as a straight forward delta planform but as it matured one can see the extension to the leading edge at about the 50% point in the length of the LE and at the same time the addition some conical camber at that point. The photo of the Concord shows extreme LE twist and prominent conical camber. Ogive would be the type of curve exhibited by the LE of the Concord wing, and the Shuttle wing, a modified delta.

 

The fact that Brian mentioned Col. Jack Brougthon in his first post, who is still alive at 89, and whose two books I have also read, that are centered on the F-105, and then the discussion about Deltas made an association in my mind...
An evocation of these well known but splendid NATO fighters meetings of the sixties; there are two Deltas in the pics, one small, one large; and a F-105...
Times of international tension, but how many beautiful planes we saw as kids in the sky...

916 Starfighter

916 Starfighter

Rgds

 

Another interesting aircraft which had the modified delta wing that Bob is talking about was the Douglas F4D Skyray - a pretty fast shipboard Navy fighter for it's day, nearly 700 mph. Of course, it did not have the weight and weapons capability to compete as the late '50s approached. An attempt was made to upgrade it as the F5D, but this failed to gain approval by the Navy.

I talked to a pilot who flew these for the Navy, and he said that they were a great handling plane, but were just short of level supersonic because the wing had a very thick structure. He said that they would go supersonic in a long dive.

I was in love with the bat shape of it as a kid, and I must have made a dozen plastic models of this plane. Still have one that I built in the 1980s.

 

Yep; the "Ford" (= F-4D) was indeed a very pretty aircraft...

 

Another promising bird that was essentially killed by the failure of the Westinghouse J40 jet engine...other than the power plant it had all the right stuff. It finally made it into the air with essentially a new engine, the J50.

Designed by Ed Heinemann based on German tailless and swept wing research in 1948, it did not see production until 1956, by which time it was out of date. It could have been a world class champion if it had been operational in 1952 - with an engine that made more heat than a Westinghouse toaster-oven.

 

About engines...there was also "some" german ADN in the french "Mirage III", but curiously not so much in the airframe + wing and its delta shape, but in the engine.

The french had access to german research on the delta shape just after the war, of course, but were in fact already quite familiar with that shape due to the work of a not-so-well-known french designer, Roland Payen, who did built a delta prototype in the thirties (admitted, Lippisch was already searching the subject in Germany during the thirties also).
So the choice of a delta shape was not so unexpected for the first prototypes of what was to become, ultimately, the "Mirage III".

But what made the definitive "Mirage III" possible was the availability of a good turbojet, the ATAR 9C, which descended from the German BMW 003 of second world war.
ATAR means "Atelier Technique d'Aéronautique de Rickenbach" ("Technical Works for Aeronautics in Rickenbach"), Rickenbach being a german town on the border of the Bodensee (Lake of Constance) were some members of the former BMW works were employed just after the end of the war to transfer their know-how and technology to the french, for what should become a very sucessful family of engines...

Rgds