German radio-controlled explosive boat built in 1944 called the Tornado. It used the floats from a Junkers Ju-52T three-engined float plane and the jet engine Argus As 109-014 from a V-1 bomb.
Loaded with 700 kg of high explosives, it was to be piloted to within half a mile or less of an anchored enemy vessel by an onboard driver, who then bailed out to be retrieved later.
The jet boat was then piloted to the target by a radio control in a nearby command boat. After the enemy vessel was sunk, the command boat retrieved the Tornado pilot and headed back to port.
This technique had seen limited success using more conventional speed boats, and the Tornado was designed to up the ante in both speed and explosive power.
The Tornado was never used in combat, and no photos of it exist. It was tested and shown to work well enough in smooth water, with speeds up to 53 mph or so. The development area was over-run by advancing Allied troops before the Tornado was ever used as intended.
The single prototype was destroyed to keep it from falling into Allied hands.
Dimensions:Â 10 x 10 x 5 cm