page_title: Canon de 75 modèle 1897
section_title: Hydro-pneumatic recoil mechanism
hierarchical_section_title: Canon de 75 modèle 1897 / Development / Hydro-pneumatic recoil mechanism
context_page_description: The French 75 mm field gun was a quick-firing field artillery piece adopted in March 1898. Its official French designation was: Matériel de 75mm Mle 1897. It was commonly known as the French 75, simply the 75 and Soixante-Quinze. The French 75 was designed as an anti-personnel weapon system for delivering large volumes of time-fused shrapnel shells on enemy troops advancing in the open. After 1915 and the onset of trench warfare, other types of battlefield missions demanding impact-detonated high-explosive shells prevailed. By 1918 the 75s became the main agents of delivery for toxic gas shells. The 75s also became widely used as truck mounted anti-aircraft artillery. They were also the main armament of the Saint-Chamond tank in 1918.
  The French 75 is widely regarded as the first modern artillery piece. It was the first field gun to include a hydro-pneumatic recoil mechanism, which kept the gun's trail and wheels perfectly still during the firing sequence. Since it did not need to be re-aimed after each shot, the crew could reload and fire as soon as the barrel returned to its resting position.
context_section_description: The gun's barrel slid back on rollers, including a set at the muzzle, when the shot was fired. The barrel was attached near the breech to a piston rod extending into an oil-filled cylinder placed just underneath the gun. When the barrel recoiled, the piston was pulled back by the barrel's recoil and thus pushed the oil through a small orifice and into a second cylinder placed underneath. That second cylinder contained a freely floating piston which separated the surging oil from a confined volume of compressed air. During the barrel's recoil the floating piston was forced forward by the oil, compressing the air even further. This action absorbed the recoil progressively as the internal air pressure rose and, at the end of recoil, generated a strong but decreasing back pressure that returned the gun forward to its original position. The smoothness of this system had no equal in 1897, and for at least another ten years. Each recoil cycle on the French 75, including the return forward, lasted about two seconds, permitting a maximum attainable firing rate of about 30 rounds per minute.
caption: Canon de 75 breech mechanism.
exif: {"Image ImageDescription": "", "Image Make": "SONY", "Image Model": "DSC-T10", "Image Orientation": "Horizontal (normal)", "Image Software": "Microsoft Windows Photo Gallery 6.0.6001.18000", "Image DateTime": "2008:11:10 14:48:24", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "2320", "Image PrintIM": "[80, 114, 105, 110, 116, 73, 77, 0, 48, 51, 48, 48, 0, 0, 2, 0, 2, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0]", "Image Padding": "[]", "Image OffsetSchema": "44", "EXIF ExposureTime": "1/8", "EXIF FNumber": "4", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "320", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2008:11:10 19:43:09", "EXIF DateTimeDigitized": "2008:11:10 19:43:09", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "8", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "29/8", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "1203/100", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "2304", "EXIF ExifImageLength": "3072", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF Padding": "[]", "EXIF OffsetSchema": "4140"}