During the protracted period when Hamilton-Standard, Sikorsky, and Chance Vought found the going rough as they endeavored to create new products that could be sold to a reluctant government, Pratt and Whitney for a while made much smoother weather of it. The Wasp engine had proved so outstanding that no other power plant had challenged it, and in a field that offered the greatest volume. Subsequent engines, while not outclassing all competition, as had the Wasp, won a fair share of the market. As a matter of fact, it was Pratt and Whitney that had provided most of the resources out of which the other divisions had prosecuted their new developments. But now as the year 1937 arrived, even the bellwether of our flock began to find the pickings scarce. For certain ones in the Army Air Corps still persisted in advocating liquid cooling, and now, as they began occupying positions of power, they pressed harder than ever, this despite the fact that the brilliant performance of the air-cooled radials had all but driven liquid-cooled in-line engines out of the country. In England, however, where the Bristol air-cooled engines had not attained to the same leadership as had the Pratt and Whitney and Wright radials in America, Rolls Royce had done an outstanding job with a racing-plane engine which they had later developed into a fine pursuit engine. In Germany, where tremendous effort was being made to rehabilitate aviation after the terms of the Treaty of Versailles had been modified, Junkers had taken a license to build Pratt and Whitney engines but, as usual, had not built power plants wholly comparable with the original. Simultaneously B.M.W. had prosecuted the development of their own liquid-cooled engines, a type in which they had background and experience. These facts, plus some new liquid-cooling developments, had encouraged certain men in the Army to promote an American liquid-cooled program. By using Ethylene Glycol, or Prestone as we know it in our automobile antifreeze mixtures, many of the difficulties inherent in liquid-cooling were ameliorated. The new “pressure-cooling” systems became competitive with the “baffles” of the radials in so far as weight and performance were concerned; they still retained the old handicaps of leaky plumbing. In order to exploit this progress, the Army Engineering Division at Wright Field had designed a liquid-cooled, in-line engine of its own, and turned over the job of building and testing it to the Allison Engineering Company, of Indianapolis, Indiana.