Wax nostalgic about and learn from the history of early
mechanics and electronics. See articles from
Popular Mechanics,
published continuously since 1902. All copyrights hereby acknowledged.
Beginning in the early days
of World War II (September 1,
1939 - September 2, 1945), Hitler's navy was laying mines in the water that
were triggered by the magnetic field surrounding the metallic hulls of military and merchant ships.
They usually floated just below the surface or even lay on the sea floor near
shallow ports so as to avoid visual sighting, and
then would detonate when ships passed overhead. It was like laying a spring leg
trap on the ground and covering it with leaves. The ship's crew would never see it coming. The
magnetic mines were as deadly and menacing as any
U-Boat. The problem was so
dire that by January 8, 1940, British engineers and flight crews had
successfully designed and implemented a system for detonating the magnetic mines
using a Vickers Wellington bomber (an amazing feat of aeronautical engineering
in and of itself) fitted with a 51-foot diameter electromagnetic coil under its
belly, powered by a Ford V-8 engine. The system was called Directional Wireless
Installation (DWI). Because the war in Europe was still in progress, not much
detail could be obtained or printed in 1943 when this news bit appeared in
Popular Mechanics magazine. Now there are many good sources on the history
of the
Vickers Wellington DWI, including this great documentary video.
"Flying Hoop" Explodes Mines by Magnetism
When Hitler sprang magnetic mines as a secret weapon, Britain countered with
a secret of her own, a - plane that exploded them from the air.
Vickers Wellington DWI (Directional Wireless Installation) fitted with a
51-foot diameter metal hoop used
for exploding enemy water mines.
When magnetic mines threatened the sea lanes around England late in 1939, the
menace was met by equipping British bombers with a hoop device, holding a magnetic
coil to which current is supplied by a Ford V-8 engine inside the hull. The magnetic
field created within the ring is sufficient to explode the Nazi mines, which Hitler
considered a prime "secret weapon." Existence of the ring-equipped bombers, long
a secret, was revealed in the British Air Ministry's book, "Coastal Command."
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