In most American designs, a gas-generator engine would dump the exhaust from the turbines overboard. In the case of the M-1, the resulting exhaust was relatively cool, and was instead directed into cooling pipes on the lower portion of the engine skirt. This meant that liquid hydrogen was needed for cooling only on the high-heat areas of the engine —the combustion chamber, nozzle and upper part of the skirt— reducing plumbing complexity considerably. The gas entered the skirt area at about , heating to about before being dumped through a series of small nozzles at the end of the skirt. The exhaust added of thrust.