does anyone know if helicopters were invented before/during ww2? the reason i m asking this is because on the box art of a german u boat kit appears to be what looks like a primitive form of a helicopter with german markings on it. if they were invented does anyone know their manufacturer etc?

The thing being towed by a sub is probably the Foche Achgelis 220, which was a more of a rotary wing glider (being unpowered) than a helicopter. The Germans experimented with many helicopter variants before / during WW2.

The first instance of a powered rotary wing flight I can think of took place ... right around WW1, as I recall.

Hope this helps,
Mika

Both the US and Germany employed early helicopters during WW2. I believe the US used them with their Air Commando units in the CBI theater. They were primarily for evacuation purposes.

Rotary wing craft were flying prior to WW2 in the form of autogyros where the engine drove a prop and the forward motion thus derived caused the rotor to auto-rotate and provide lift.
In Europe the Cierva autogyros were quite common in the thirties. In the US the Kellet company held the Cierva licence and developed the original design. By 1938 the US Army were trialing the Kellet YO-60 but I do not know if it ever saw service.
Sikorsky had a helipcopter flying in 1939, the VS-300. A development, the VS-316 was operated by the USAAF as the XR-4/YR-4/R-4B. It saw operational service in the Pacific theatre by 1944 but I fancy this was more experimantal than serious front line stuff. As with all early rotary wing craft power was always a problem with very limited payload and dodgy 'hot and high' performance.
Theres some utterly useless information for you!

Regards Dave