# Could Concorde have used swing wings?

Would it have been possible to equip the Concorde with swing-wings to help with lift at lower speeds? The delta wings on the aircraft worked well at high speeds, but it took a long time for it to achieve takeoff speed. A swing-wing would give it the aspect ratio for low speeds and delta form for the high speeds.

• The advantages of Variable Geometry Wings are that they give more range and payload capacity over a conventional design. But on the downside the mechanism needed to operate was heavy and complex. So the Concorde would be better off without it in my opinion. It had not much payload other than 100 passengers. Less weight and subsequently less fuel consumption would be better off than some low speed maneuvarability. – user12782 Dec 27 '15 at 16:54

Actually, the Boeing design for the SST (Super Sonic Transport), the Boeing 2707 had a swing wing (swing wing was the hot thing during that time). It is instructive to look at what happened to that design.

Image from up-ship.com

The 2707 concept was a larger aircraft, with a 174' wingspan for TO/landing and low speed regime (In comparison, Concorde had a 84' wingspan and carried half the passengers). While the wings were swept back, the wing area increased from 1828 $m^{2}$ to 2743 $m^{2}$.

The engines were carried on the stabilizers. During the development Boeing had significant problems associated with the swing wing mechanism. Concerns about stability and payload capability lead the design to be lengthened and added canard to the front to meet rotation requirements, though the new design 2707-200 kept the swing wings.

Image from up-ship.com

However, these changes did little to solve the problems. When kept near the centerline, the hinge mechanism interfered with the undercarriage. The hinge mechanism was so heavy that it negated the advantages of swing wing, leading to a very poor payload to weight ratio. Studies indicated that the aircraft would run out of fuel halfway across the Atlantic, essentially killing the project.

Due to this, Boeing decided to use a fixed wing platform in its next iteration, the 2707-300, which looked quite similar to Concorde.

"Boeing 2707-300 3-view" by Nubifer - Own work. Licensed under CC BY-SA 3.0 via Commons.

• While the wings were swept back, the wing area increased from 1828 m2 to 2743 m2 Why does swinging the wings backward increase the area? – ROIMaison Jan 25 at 13:31

Well, it would help with low speed lift, but it would have the following problems:

1. The fuel tanks in the wings would have to be rearranged significantly affecting the CG, CL, and CP. As seen in the diagram below, the fuel tanks fill most of the wing, so the wing at low-speed mode would create stresses on the airframe as well.

1. The engines would also have to be relocated to another position, which without even more modifications to this airframe could not have been done.

2. The swinging mechanism for the wing would have taken up much room because it had to move a wing of such size.

So, if the Concorde would have had swing-wings, it would have been a radically different airframe. However, because of the difficulty of making a swing-wing mechanism for such a large aircraft (Existing swing-wing aircraft are either small compared to airliners or have plenty of room for the mechanism) and the many more forces involved with this, it would not have been a good idea.

Diagram and source here

• "Existing swing-wing aircraft are relatively small compared to passenger airliners" - I don't agree, the MTOW of the Rockwell B-1 Lancer (swing-wing) is higher than that of the Concorde and the A321-200, to name a few – ROIMaison Dec 23 '15 at 12:31
• @ROIMaison Will change that – SMS von der Tann Dec 23 '15 at 13:16