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Curtiss E-4, In-Line 4 Engine


Display Status:

This object is on display in the Early Flight exhibition at the National Air and Space Museum in Washington, DC.

Collection Item Summary:

It is believed this artifact is a 37 kW (50 hp) Curtiss E-4, operated at a lower than normal rotational speed. It was the first of Curtiss water-cooled engines, and the first of two engines to power the U.S. Army Signal Corps Dirigible No. 1, the first U.S. military airship. The engine drove a tubular steel shaft about 6.7 m (22 ft) long on which was mounted a wooden propeller designed by Lt. Thomas E. Selfridge.

In 1908, the Signal Corps awarded Thomas Baldwin a contract for the construction of an airship not to exceed 36.6 m (120 ft), to be completely maneuverable, and to obtain a speed of 32 km/hr (20 mph). Baldwin piloted the airship, and Glenn Curtiss was the engineer. In the official speed run, the Baldwin airship reached 31.38 km/hr (19.61 mph).

After service at Fort Meyer and Omaha, this engine was replaced by another Curtiss Model E-4 engine, also in the museum’s collection.

Collection Item Long Description:

Data Source

National Air and Space Museum


Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum


Glenn H. Curtiss

Credit Line

Gift of Charles R. Witteman.


metal, wood


  • Approximate: 91.4 × 61 × 91.4cm (36 × 24 × 36 in.)
  • Support: 171.5 × 106.7 × 82.6cm (67 1/2 in. × 42 in. × 32 1/2 in.)

Country of Origin

United States of America



Physical Description

  • Type: Reciprocating, in-line, 4 cylinders, water-cooled
  • Power rating: 14.9 KW (20 hp) at 450 rpm
  • Displacement: 6.4 L ( 393 cu in.)
  • Bore and Stroke: 127 mm (5 in.) x 127 mm (5 in.)
  • Weight: 114 kg (250 lb)


PROPULSION-Reciprocating & Rotary

Inventory Number