The steam collected in the separators was vented separately from the liquid coolant. The steam did not require mechanical pumping to do this, and the buildup of pressure inside the separator was sufficient. The steam was piped down the lower right side of the engine bay and led into the open spaces between the upper and lower wing skins of the outer wing panels. There, it further expanded and condensed by cooling through the skins. The entire outer wing, both ahead of and behind the main spar, was used for this purpose covering that portion of the span containing the ailerons (the fuel was also carried entirely in the wings and occupied the areas behind the main spar in the center section and immediately ahead of the outboard flaps). The condensate was scavenged by electrically-driven centrifugal pumps and fed to the header tanks. Sources indicate as many as 22 separate pumps were used for this, each with their own attendant pilot light on the instrument panel, but it is not clear whether that number includes all of the pumps in the entire water- and oil-cooling systems or merely the number of pumps in the outer wing panels. The former is generally accepted.