“G and You” is a 1943 U.S. Navy training film about the measurement of G-force, a force per unit mass, and its effects on the body regarding flying and gravity. To help counter the effects g-force when flying fighter and dive bomber aircraft, pilots are given anti-blackout g-suits that provide essential pressure points that help blood flow normally. Classified as a confidential film, it was originally released for the viewing of authorized personnel only. The film was produced under the supervision of the Bureau of Aeronautics for the Bureau of Medicine and Surgery. The animated segments in the film were likely made by the Walt Disney Co., which contributed to many wartime training films.

(0:49) As airplanes fly, energy is required to change direction, with this momentum having an effect on the human body. A harness protects the pilot from the resulting momentum from a crash landing. Centrifugal force feeds this momentum that launches you forward (3:22) Your resulting weight is due to the force of gravity, and centrifugal force changes your effective weight, so it is measured in terms of the pull of gravity with the expression “G”. One G is normal, can be positive or negative, and can change when you turn the plane. It can be measured with an accelerometer (6:10) A pull-out from a dive can increase the G acting downwards x7 or more, resulting in you and the plane weighing x7 normal. Your blood will be heavy and not circulate, resulting in you blacking out (8:00) The effects of G can also be studied on a human centrifuge in a controlled environment with cameras on the subject (11:31) Blackouts result from effects on blood circulation and G. Blood gets heavier during tight maneuvers of the plane, with the blood driving downward in the bloody. Blood pools in your lower regions with the blood trying to return to your heart and go to other organs in your head slowing down. Everyone’s threshold can vary, but most will black out at 6 G (17:25) Negative G acts on the blood in the same way, but in the opposite direction in the body, with blood forced toward the head. This results in more mental confusion and you can black out at a lower level. However, good physical condition, sleep, a full stomach, and crouching and raising your feet while in flight can help reduce effects and increase your threshold (23:25) Anti-blackout suits with tubes that push pressurized air to specific regions can equalize pressure in flight and prevent veins from expanding too much, resulting in equilibrium in the body. Attached to the plane, it activates once a certain G level is reached. A demonstration of the suit is done using a pilot in a lab (30:12) The suits are fitted carefully to each pilot. Various zippers and lacings help ensure a snug fit (34:53) A flight test is conducted on a plane fitted with a camera. When flight levels reach above 7 G, it is possible to still black out even with the suit. However, the suit can raise the human threshold by several G despite not being fully G-proof (36:23) Even though the suit protects you, the plane still has a limit. Fighter planes can take 7 to 8 G, with dive bombers at 9 G but this can vary depending on the plane’s load (39:27) Despite knowing the plane’s G limits and having a suit, it’s still important to get exercise, stay healthy, and avoid negative G where possible. It gives you an edge over the Japanese and the Nazis, who may or may not know about this science yet—therefore this knowledge must be kept secret.

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This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD, 2k and 4k. For more information visit http://www.PeriscopeFilm.com