Inch Worm (oz3584)

About this Plan

Inch Worm. A2 free flight sailplane. Wingspan 64 in.

Note the Inch Worm appeared as a kit in 1955 from Contest Kits. This here is a later plan redrawn by Martyn Pressnell, that appeared in 1997(?) Aeromodeller.

Quote: "Next a very interesting article on Mick King's classic 1954 Nordic A2 Sailplane Inch Worm by Marty Pressnell. Martyn has recreated the Contest Kits plan and it was printed as a quarter page reproduction with the article. Have once again scanned it at my highest setting and it should be usable blown up to full size. There is a current Inch Worm thread to be found here: http://www.rcgroups.com/forums/showthread.php?t=1753244"

Quote: "Inch Worm. Mick King's 1954 Nordic A2 Sailplane, recalled by Martyn Pressnell.

Each model has a history. It starts life full of hope and promise, and sometimes this is realised in that the model proves a thoroughbred and achieves sparkling success in its time. 'Inch Worm' is one such model, tracing its origins to the first A2 competitions staged in the UK before 1950.

The designer, Mick King, was the secretary and general factotum of the Belfairs MAC, of Leigh-on-Sea, Essex. He had completed National Service and, with other energetic members, influenced the club to be strongly competitive at that time. Major success came to him when he was selected to fly for Britain in the A2 championships staged in Austria in 1952. The model flown was of a higher aspect ratio than 'Inch Worm', complied with the fuselage cross-section rule, but otherwise established the design style of subse-quent A2s built in the club.

'Inch Worm', named after a song made popular by Danny Kaye in the film 'Hans Christian Andersen', was developed to gain advantage from a fast tow and zoom launch which, as a tall and strong person, Mick could exploit. This explains the lower aspect ratio and strong wing structure. The wing section probably owes its origins to the Danish Hansen school. However, Mick experimented systematically with trailing, edge droop, and settled on a rather unusual, fairly thick section. The highly curved leading edge was equipped with three spanwise threads to support the covering, and this was one of the first applications of turhulators on such a model. The fuselage is minimal to reduce wetted area, and to minimise pitching inertia.The nose is very short, and perhaps initiated that trend also.

The performance of this A2, and particularly its tight turning thermal flight, surpassed expecta-tions. In the hands of many flyers over the next decade it was to prove almost unassailable in rough British competition conditions, and built up a remarkable record of national successes. It was fitting that it should be one of the first models to be kilted by Contest Kits in 1955 when that company was founded by Mick King. Before the end of the decade the company was sold to Keil Kraft, who continued to produce 'Inch Worm' for a short time.

As a young member of the Belfairs club, my own initiation to contest flying took place with similar gliders. and it was my pleasure at that time to help pack the kit boxes for Inch Worm, Empress (oz11069), Calypso (oz10559) and several others. As the name implies, Contest Kits aimed to produce the best in com-petition models, and 'Inch Worm' was the leader in that stable.

The SAM competition rules have recently been revised to make glider designs to 1956 eligible, so that the 'Inch Worm' becomes a very useful contender. Of course, it continues to meet the modern F1B rules and it would probably be quite competitive in rough weather conditions, with the usual clockwork systems. I have re-drawn the 'Inch Worm' plan as a full engineering draw-ing (illustrated here at reduced size) and would be pleased to offer copies to interested readers."

Supplementary file notes

Planfile includes article.

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