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Reading this question, I was wondering if, at some point early in aviation history there may have been designs or concepts anticipating variable swept wing by "expendable wingspan wing"?

For example, a heavily loaded bomber barely able to take off with its full wingspan, could jettison part of its wingspan once its mission is completed (having dropped bombs & burnt most of its fuel), to flee more quickly from enemy skies.

Ok this is not exactly what I had in mind in the first place, but it's similar. The Hawker-Hillson FH.40 Hurricane experiment is a Hurricane with one additional jettisonable upper wing, making it a biplane allowing for better take off and climb performances.

hurricane biplane experiment (source)

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    $\begingroup$ Interesting concept! In reality, the lowered weight was used to climb higher, so the pursuit became harder. $\endgroup$ Aug 14, 2019 at 21:12
  • $\begingroup$ So, I'm flying an aircraft peppered with holes, and who knows what other damage. Do I really want to take a chance that part of one wing will detach while part of the other doesn't? $\endgroup$ Aug 15, 2019 at 3:20
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    $\begingroup$ Does the Short Mayo Composite count? en.wikipedia.org/wiki/Short_Mayo_Composite $\endgroup$ Aug 16, 2019 at 16:11
  • $\begingroup$ I guess yes, nice find ! $\endgroup$
    – user21228
    Aug 16, 2019 at 17:04
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    $\begingroup$ @CamilleGoudeseune expendable in the sense it is not reusable or recoverable with parachute, like say one SIVb Saturn V stage, which is in some way also jettisoned. Don't know which fits best, feel free to edit it's not my mother tongue :) $\endgroup$
    – user21228
    Dec 24, 2021 at 12:17

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US supersonic bomber concepts were studied in the Fifties where the outer wing could be jettisoned. The WS-110 concept by North American shown below (source) sported wing extensions with fuel tanks which could be jettisoned once tank fuel was depleted and could even return and land autonomously.

North American WS-110A concept drawing

As the wing planform indicates, with extensions the airplane would cruise subsonically and only accelerate to a supersonic dash with the outer wing jettisoned.

For a practical application I nominate the F-104 with tip tanks. The tanks extended the wingspan a bit and helped to reduce induced drag, but their added surface and mass increased drag overall. Also, even with tip and underwing tanks, the F-104 was not particularly suited to long-range flights.

Another version of extendable span puts the additional wing not in parallel, but in series. Both Arado (with the Ar-234) and Messerschmitt (with the Me-262) tried to extend the range of their jets by having them tow a fuel tank with its own wing ("Deichselschlepp").

Ar-234C towing a winged tank

Ar-234C towing a winged tank (picture source)

This PDF contains a NATO paper on morphing aircraft, including a brief historical overview.

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  • $\begingroup$ Trying to apply your work to cargo/passenger aircraft. A 747 uses around 6000 gallons of fuel to reach cruising altitude and speed. A detachable glider fuel tank may be able to give them over 1 hour additional flying time. $\endgroup$ Dec 23, 2021 at 8:27
  • $\begingroup$ @RobertDiGiovanni The towed glider flies in the downwash of the airplane. This makes it very inefficient - total induced drag is as if all the mass is carried by the airplane alone. Adding structure for tank and wing adds to the total mass and friction drag. $\endgroup$ Dec 23, 2021 at 8:49
  • $\begingroup$ Yes, but the 747 or C5 Galaxy may have sufficient thrust and structural integrity to do it, perhaps saving a much more expensive air-air refueling. (I'm also trying to show Virgin they might be able to put their rocket there too.) $\endgroup$ Dec 23, 2021 at 8:55

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