This feature and the fact that the second skin fastened with hook and pile fasteners, made the whole assembly prone to leaks, a serious design flaw. The second skin wasn't sewn to the bottom of the hood, in order to pull the bottom of the hood over the outlet valve to maintain positive pressure in the hood. The butyl rubber "second skin" fastened to the facepiece with hook and pile fasteners near the bottom of the exhale valve, where a part of the hood curled under that had the patches to fasten on. To provide protection from persistent chemical warfare agents, the mask was issued with a special hood made of butyl rubber-coated nylon and had a specially made sheet of butyl rubber, sewn into the hood, that covered the facepiece, protecting the silicone facepiece from the harmful effects of persistent chemical warfare agents. The facepiece is made of olive-colored silicone rubber, as in the XM40 Series. M40A1 with Neutral Grey Outserts next to an M40 Carrying bag Inside, the mask has an inverted peripheral seal, and the chin cup has a slit to allow sweat to pass down to the exhale valve. The oralnasal cup is the same type as on the MCU-2/P. It used a 40mm threaded C2 canister which could be switched out on either side with a secondary side voice diaphragm (used for telephone communication) to accommodate left and right-handed rifle users.Ī soldier from the 70th Brigade Support Battalion, 210th Fires Brigade, 2nd Infantry Division wears the M40 during an NBC exercise in South Korea. The outlet valve had a drinking tube built into it, which wrapped around the outlet valve cover and fit in a pocket on the cover (again, similar to the MCU Series). It had a large voice diaphragm (same as on the MCU-2/P Series) which had threads on the inside to fit an M7 or MSA Voice Amplification Unit. It had two large, polygonal, binocular sight polycarbonate eyepieces, which came with a separate pair of ballistic lens "outserts", like its cousin, the M17, but these outserts also came in a neutral grey (tinted) version for protection against UV rays and flashbang grenades. The Scott Avaition version was ultimately selected. The ILC Dover and the Scott Aviation version of the XM42. It was mass-produced and mainstay issued from 1992 onwards. There were complaints about bulk, and so the mask was developed further.Īround the late 1980s, the XM40 was finalized as the M40 Field Protective Mask, but it did not enter service until after the Gulf War (in which the M17A2 was mainly used). It was similar to the first but more rigid. Later, another XM40 prototype was designed. The initial prototype was heavily influenced by the M17A1/M17A2 masks and featured a dimple under the voice diaphragm for clearing the mask, a feature dropped in later prototypes. It was a very loose design, but it helped pave the way towards the development of the M40. In 1983, the ILC Dover company came out with the first prototype of the mask - the XM40. Learning from their mistakes, the Army decided to start over. The Navy and Air Force decided to develop the design further and finalized it as the MCU-2/P. These masks, however, had several problems with the panoramic eyepiece as well as the fact that the silicone rubber it was made of was vulnerable to persistent chemical warfare agents, which diffused into the silicone and eventually exposed the wearer to that agent. In the 1970s the Army experimented with two new masks, the XM29 and XM30 series. ![]() The M17 series lacked the latest seal design, leaving it susceptible to seal breakage during strenuous military activities.Surfaces in contact with the face weren't textured, and the mask was made from stiff blended natural and butyl rubber, making it stronger, but more rigid than previous masks. M17 series masks could be quite uncomfortable with long-term wear.The use of internal filters added bulk and weight to the mask.The M17 series M13 filters were difficult and time-consuming to change and couldn't be replaced while wearing the mask.However, the M17 series had a number of shortcomings: The M17 introduced a number of innovative features absent on the previous service masks, such as a voice diaphragm and a drinking system. 8.5 Preventative Maintenance Service Check (PMSC) Flash Cards.5 M40A1 (Universal Pattern Second Skin).
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