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Junkers D I

The Junkers D I was a monoplane fighter aircraft produced in Germany late in World War I,

Significant for becoming the first all-metal fighter to enter service. 

The prototype, a private venture by Junkers named the J 7, first flew on 17 September 1917, going through nearly a half-dozen detail changes in its design during its tests.

When it was demonstrated to the Idflieg early the following year it proved impressive enough to result in an order for three additional aircraft for trials.

The changes made by Junkers were significant enough for the firm to rename the next example the J 9, which was supplied to the Idflieg instead of the three J 7s ordered.

During tests, the J 9 lacked the manoeuvrability necessary for a front-line fighter but was judged fit for a naval fighter and a batch of 12 was ordered.

These were supplied to a naval unit by September 1918, which then moved to the Eastern Front after the Armistice.


J 7

Company designation for early prototype variants, one built (three completed as J 9s).

J 9

Company designation for late prototypes and production models

J 9/II

Company designation for lengthened fuselage version


Idflieg designation



One pilot


7.25 m (23 ft 9.4 in)


9.00 m (29 ft 6.3 in)


2.60 m (8 ft 6 in)

Empty weight

654 kg (1,438 lb)

Gross weight

834 kg (1,834 lb)


1 × BMW IIIa water-cooled 6-cylinder inline,

138 kW (185 hp)


Maximum speed

176 km/h (109 mph, 95 kn)


1.5 hours

Service ceiling

6,000 m (19,700 ft)

Rate of climb

3.5 m/s (683 ft/min)


2 × fixed, forward-firing Spandau machine guns.



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