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A number of years ago, I read about a technique for cargo pickup and recovery at remote sites using a low-and-slow-flying plane. The plane would enter a slow orbit around a point on the ground and lower a bag to the ground on a long (hundreds of feet? A thousand feet?) line. Once the bag was down, the plane would maintain its turn around a point so that the line stayed slack and the bag stayed in position. Cargo (perhaps mail?) could be retrieved from or placed in the bag, then once the transfer was complete, the plane exits the circle and lifts the bag. I'm a lot less clear on that part.

However, I don't have any idea where I read about this, and haven't been able to find any more descriptions of this. Can anyone tell me if this technique is real, what it's called, where/when it's been used?

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  • $\begingroup$ This title probably isn't great, either--it's not THAT similar to the skyhook, but it's what comes to mind. Would appreciate help there. $\endgroup$
    – Erin Anne
    Apr 1, 2015 at 4:10
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    $\begingroup$ Surprised to see this question getting love three years later, but after some initial "who moved my cheese" skepticism I like the new title. Thanks. $\endgroup$
    – Erin Anne
    Jun 5, 2018 at 21:17
  • $\begingroup$ I like cheese... $\endgroup$
    – Pilothead
    Jun 6, 2018 at 19:16

5 Answers 5

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See the notes on this page under the "Delivery" section. Looks like its formally called " long-line loiter". There is a brief note on it here and a US Patent here and this manual from the 70's that seems to show how to do it and some related research on it.

Here is a nice image of the maneuver enter image description here

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  • $\begingroup$ Brilliant. There's a ton of information in the military "manual", which is actually a report on the feasibility of retrieving personnel via this method. Spoiler: <2G max acceleration! $\endgroup$
    – Erin Anne
    Apr 2, 2015 at 3:29
  • $\begingroup$ Happy To Help ! $\endgroup$
    – Dave
    Apr 2, 2015 at 3:31
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Most people credit it to Nate Saint's technique (and it's probably been rediscovered many times), but there are much earlier references.

Popular Science, December 1934:

Picture of long-line-loiter from 1934

...at Tulsa, Okla. Circling an air field at 1,500-foot altitude, [A. V. Muzzey, credited here as inventing the technique] lowered a sack of eggs safely to the ground, and hauled aloft a live chicken that a ground assistant attached to the cable in exchange.

And, although it's not technically long-line loiter, a patent from 1942 using multiple aircraft:

Patent for circling pickup

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    $\begingroup$ Wonderful answer. I hope you and the community will indulge my edit, which elevates a quote from the Popular Mechanics article about the chicken/egg exchange into the answer text. $\endgroup$
    – Erin Anne
    Jul 2, 2020 at 21:09
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I don't know the name of the technique, but I know Mission Aviation Fellowship pilots used it in Ecuador in the 1950's. You can achieve a similar effect by whirling a the end piece of dog-chain or similar hanging from your hand around in small circles. The chain will form a bow shape, and the bottom will stay roughly in the same place. Hand = plane, rope = chain... put the bucket on a swivel... Changes in speed or hand orbit can lift the end of the chain.

Wish I could fly like that...

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Developed by the USAF Aeronautical Systems Division (ASD), the gunship applied a principle adopted by bush pilots in South America. This was the use of a weighted bucket suspended on a rope from an aircraft flying a very tight continuous turn to keep the bucket stationary at the tip of an imaginary cone for the collection of mail and the like from inaccessible sites.

Source: Defenders: a comprehensive guide to the warplanes of the USA, Oriole, 1989.

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I saw a similar technique to pick up personnel. A balloon was floated up, and a plane with a big V in front collected the line and pulled the person up. Pictures and more description here CIA's Fulton surface-to-air recovery system (STARS)

This was used in a couple of the early James Bond (007) movies also.

Similar can be done to what banner tow pilots do. A line is strung between two poles, the plane flies above with a hook on a rope to grab the line and then takes off full power, with lots of slack to give the plane time to climb and gain some speed before the load's drag kicks in.

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    $\begingroup$ The Skyhook method used to be mentioned in the title, and is explicitly not what this question is about. $\endgroup$
    – Erin Anne
    Jun 6, 2018 at 20:33

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