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Aero Ae.04

Single-Seat Biplane Fighter Prototype

The Aero Ae.04 biplane fighter succeeded the abandoned Ae.02 series though, again, only one flayable prototype was made.
Authored By: Staff Writer | Edited: 6/21/2018
National Flag Graphic


Year: 1921
Status: Cancelled
Manufacturer(s): Aero Vodochody (Aero) - Czechoslovakia
Production: 1
Capabilities: Fighter; X-Plane;
Crew: 1
Length: 18.37 ft (5.6 m)
Width: 25.26 ft (7.7 m)
Height: 8.86 ft (2.7 m)
Weight (Empty): 1,477 lb (670 kg)
Weight (MTOW): 1,984 lb (900 kg)
Power: 1 x BMW IIIa 6-cylinder water-cooled inline piston engine developing 185 horsepower and driving a two-bladed propeller at the nose.
Speed: 140 mph (225 kph; 121 kts)
Ceiling: 19,685 feet (6,000 m; 3.73 miles)
Range: 140 miles (225 km; 121 nm)
Rate-of-Climb: 1,140 ft/min (347 m/min)
Operators: Czechoslovakia (cancelled)
Further work by Aero (of Czechoslovakia) on the Ae.02 of 1920 - Czechoslovakia's first indigenous fighter - resulted in the evolved Ae.04 of 1921. This design took all that worked in the Ae.02 and introduced some Czech air service required changes to it to produce the new aircraft. Like the Ae.02 before it, however, the Ae.04 was only produced in one flying prototype and this form was also not accepted into service with any one world power - even Czechoslovakia.

Part of the Czech air service changes included installation of the German BMW IIIa 6-cylinder water-cooled inline piston engine of 185 horsepower (locally-made under license). This was used to drive the two-bladed propeller at the nose. The fuel tank was relocated to the fuselage and an automobile-style radiator was seated behind the propeller unit. The wings (unequal-span, I-frame struts) were retained from the earlier Ae.02 as was the single-seat, open-air cockpit and twin 7.7mm Vickers machine gun arrangement.

A first-flight was had in 1921 and performance included a maximum speed of 140 miles per hour (cruising speed of 115mph), a service ceiling of 20,000 feet and mission endurance window of one hour flight time. 16,000 feet cold be achieved in about fourteen minutes. The prototype claimed a new altitude record of 20,869 feet during its time aloft. Later in its life, the aircraft sported a revised engine cowl and chin-mounted radiator unit which revised the appearance of the nose considerably.

Beyond additional flight testing and an appearance at the 2nd International Aircraft Exhibition in Prague, the Ae.04 followed the Ae-02 into Czech air history by being superseded by another design, this becoming the Aero A.18 of 1923.


2 x 7.7mm Vickers Machine Guns synchronized to fire through the spinning propeller blades.

Graphical image of an aircraft medium machine gun

Variants / Models

• Ae.04 - Base Series Designation; single prototype completed.
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