In looking at Bft4/5 kites I have been reminded of the successful use of the box design as an emergency radio antenna lifter by air forces in WW2.
The most well known is Box Kite M-357-A, made in the thousands by the Bendix Aviation Co. from 1941. The design is of interest as it’s collapsible and ‘idiot proof’. The aluminium frame used an ingenious ‘pop-out spider’ to make assembly easy. It was made to lift 260 feet of stainless steel wire antenna as flying line. So it was a good lifter too.
The instructions are printed on it:
The famous emergency radio (from which the ‘Gibson Girl’ nickname is derived- it had an ‘hour glass’ shaped case) and its box kite lifted antenna was developed from a 1941 captured German example which used a winged box (see Louis Meutlstee’s excellent account here). The British adopted the system and it went into mass production in the US. 11,600 sets were ordered to be made as standard issue for all aircraft operating over sea. It was in use as US air force kit up to the 1970s. The complete emergency radio kit included a balloon and hydrogen generator as an alternate to the kite.
A good description of the system is posted on the excellent Carnet deVol website by Patrick and Patricia Mouchague here.
The risks of raising the antenna by hydrogen balloon and kite had to be spelled out in the manual!
It appears that by1943 the RAF antenna raising system was refined further. They seemed happy with the radio but the box kite was superseded by a Conyne design which could be rocket launched from a Very pistol:
I am unsure as to why the RAF went for this, perhaps supply problems with the Bendix kite or a research team gripped by kite fever- who knows? I assume the Very pistol would have been onboard any aircraft so the rocket launched Conyne kite would be less bulky than the box, or perhaps there was a fear of launch failure. Maybe it was felt that downed pilots and crew shouldn’t have to assemble the kite? Here is the kit :
Launch procedure was pretty scary but straight forward:
A rocket launched kite seems very appealing, it would be a good method of getting a kite clear of ‘dirty’ airflow at ground level. Mind you I can see some problems, having to deal with an instant 200′ of line might create more problems than it solves if the kite swings into the wind and drags the line over the usual obstructions- best used at sea I suppose!
I’m left with a few unanswered questions about the use of kites in WW2 as emergency radio antennae:
- Why did the RAF appear to drop the Bendix box kite so soon after it went into production?
- What was the advantage of the rocket launch system?
- The ‘Rocket’ Conyne has a full sail, most examples of the design are open between the cells, why was this?
- How did the rocket launched Conyne work in practice? How does the ‘runner’ work?
- The German winged box kite seems to have a central ‘spacer’ spar as part of its ‘pop-up’ assembly mechanism-how did it work?
- There are 3 kite designs deployed : a winged box, a box and a Conyne: which is best as a Bft4/5 KAP lifter?
I know many examples of the M357A survive (they were a popular post war toy for many!) but info on the British ‘Rocket Conyne’ and the German winged box is scarce, it would be fun to find and fly these warkites, their designs have the robust utility of working tools that appeals!
B
