<text id=00he0112><title>The Corps Buys a Dirigible</title>
<history>US Air Force: Events History</history>
<article><hdr>The Corps Buys a Dirigible</hdr><body>
<p>Brigadier General James Allen, then Chief Signal Officer, was an official observer at the 1907 James Gordon Bennett International Balloon Race in St Louis. An air meet was scheduled to follow the races, and Genera; Allen stayed on to watch the flying.
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<p>A dirigible competition was a feature of the air meet, and one of them was well demonstrated by Thomas Scott Baldwin, a former wire-walker, parachute jumper and general daredevil. Allen talked with Baldwin about acquiring a dirigible for the Corps, and Baldwin was interested.
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<p>Soon after, the Corps issued a specification and a request for bids for a dirigible to carry two persons plus 100 lb (45 kg) of ballast at a maximum speed of 20 mph (32 km/h). The material for the envelope, a lamination of silk and rubber, would be furnished by the government.
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<p>Most prospective bidders were furious; they knew nothing about the proposed material which, in fact, was one of Baldwin's ideas turned to reality by a fabric manufacturer. It was an unfair restriction, they argued, and they won. The Corps issued revised Specification S.C. 483 on 21 January 1908. It made the contractor responsible for choosing the envelope material, but it specified a breaking strength for the fabric, and the restriction that varnished material could not be used.
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<p>Hydrogen was to be the lifting gas; developed lift had to be sufficient to carry two persons weighing a total of 350 lb (158 kg), plus ballast weighing 100 lb (45 kg). Dimensions were left to the contractor with the single restriction that overall length could not exceed 120 ft (36 m). Required speed was still 20 mph (32 km/h), with penalties for every mile per hour below that speed and rejection if the craft did not exceed 16 mph (26 km/h). Endurance was to be two hours. Three speed and three endurance trials were allowed, to be conducted by the contractor within 30 days after delivery of the craft to Ft Myer, and the costs of the trials were to be borne by the contractor.
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<p>Baldwin was the low bidder, at $6,750 and 150 days until delivery, and received a contract on 24 February 1908. Other bids varied to a high of $33,000 and a delivery time of 250 days. Glenn Curtiss, whose lightweight engines had powered Baldwin's earlier dirigibles, began work on a new, water-cooled, four-cylinder engine to deliver 20 hp (16 kW).
