<p>Baldwin's design was typical. An openwork nacelle was slung below a cylindrical gas bag with pointed ends. At the forward end of the nacelle was a propeller, driven by a 22-ft (6.7-m) long shaft that extended from the Curtiss engine, mounted in the nacelle about one-third of the way back. Just behind the engine sat the forward pilot, who controlled the engine and the movements of the dirigible in a vertical plane. He operated a set of control surfaces like short-span wings extending from the sides of the nacelle. Toward the rear sat the second pilot, whose function was to man the rudder and provide directional control of the airship.
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<p>Final lift figure was approximately 1,350 lb (612 kg), 500 lb (227 kg) of which was charged to two pilots, ballast, fuel and useful load items.
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<p>Signal Corps Dirigible No. 1 was delivered to Ft Myer during the week of 20 July, and was ready for flight tests by 4 August. The first flight lasted seven minutes and reached an altitude of 250 ft (76 m), but proved the ability of the machine to fly. Over the next week, Baldwin and Curtiss, his co-pilot, made several tests, including two over the course that had been selected for the official speed trials.
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<p>On 12 August the official test flights began, and the engine promptly failed on the way. Repaired on the site by Curtiss, the engine was restarted and returned the dirigible to Ft Myer, but the test was a failure. On 14 August, the two aeronauts completed the course, at an average speed of 19.61 mph (31.56 km/h), and the trials board concluded that the figure was close enough.
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<p>The next day, the dirigible passed its endurance tests and on 18 August Baldwin was notified officially of its acceptance by the Corps. All that remained was to instruct two officers to fly it. Baldwin started with three pupils: Lieutenants Frank P. Lahm, Benjamin D. Foulois and Thomas E. Selfridge.
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<p>Dirigible No. 1 led a short life, first at Ft Myer and later at Ft Omaha, Nebraska, the Signal Corps' designated site for lighter-than-air development.
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<p>Hydrogen gas was made then by treating iron filings with sulphuric acid, and then collecting and separating the gas that resulted. A small quantity of moisture-laden gas, still holding some particles of acid, always got through the gas processors and into the envelope. It ate pinholes into the fabric, reducing the lift by allowing gas to escape. Within two years of its purchase, No. 1's lift had been reduced to the point where only small, light men were able to fly it from the forward position.
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<p>Finally, even that weight was too much, and the dirigible was jury-rigged to permit flights by a single pilot from the rear position. He also had to move fore and aft along the framework of the nacelle to change the trim of the ship, and it was soon apparent that this was no way to fly. Besides, the airplane was now coming into its own and offered more promise than an ungainly bag of gas. Signal Corps Dirigible No. 1 was condemned and publicly auctioned in 1912.
