Junkers J 26
| Industry | Aerospace |
|---|---|
| Founded | 1895 |
| Headquarters | Germany |
The Junkers T 23 was a German experimental two-seat, single-engine training aircraft from the early 1920s. Its distinctive design permitted operation either as a parasol wing monoplane or as a biplane, allowing direct evaluation of their respective flight characteristics. A total of four units were produced.
Design and development
The T 23 belonged to a select category of aircraft that could be configured both as a monoplane and as a biplane. The monoplane variant, designated T 23E (with "E" standing for Eindecker), featured a parasol wing arrangement, while the biplane version, T 23D (Doppeldecker), was designed as a sesquiplane. This model was an enlarged, two-seat derivative of the parasol-winged Junkers T 19, intended for experimental evaluation and to explore the light aircraft market by determining whether the increased wing loading of the monoplane could still offer the forgiving handling qualities vital for pilot training.
Primarily constructed from duralumin, the airframe combined a tubular structure with corrugated sheet metal skinning, sharing numerous design traits with the T 19. The wing incorporated a constant chord center section complemented by tapered outer panels equipped with extended ailerons; its span exceeded that of the T 19 by 2.5 m. The forward V-shaped cabane struts were similar to those on the T 19, whereas the rear struts resembled those used on the T 21. The cantilever parasol wing of the monoplane required no external bracing, in contrast to the biplane setup which added a lower wing beneath the fuselage. This lower wing was supported by vertical V struts near its tips connecting it to the upper wing. It measured only 77% of the upper wing’s span, increasing overall wing area by 57% and adding approximately 75 kg to structural weight.
The fuselage, characterized by flat sides, accommodated tandem cockpits: the pilot’s seat positioned beneath the leading edge of the wing and an instructor’s cockpit directly aft under the wing, accessed through a door on the starboard side. The tail assembly featured a tailplane mounted atop the fuselage with horn-balanced elevators; a triangular fin carried a flat-topped rudder extending between elevator cut-outs. The main landing gear consisted of shock-absorbing legs attached to upper fuselage longerons with forward bracing struts and a centrally hinged axle connecting the wheels below.
Propulsion was provided by an 80 hp (60 kW) Le Rhône rotary engine housed within a circular cowling, driving a two-bladed propeller.
Operational history
The initial flight of the T 23 occurred on 14 September 1923 in its biplane form. Following several months of evaluation, it was converted into its monoplane configuration. Compared to its biplane counterpart, the T 23E demonstrated higher takeoff and landing speeds along with longer takeoff runs due to increased wing loading. It also achieved a speed advantage of 15 km/h and could carry roughly 9% more payload. Upon completion of testing, all four T 23 aircraft were sold to flying clubs.
Variants
- Junkers T 23D
- (D - Doppeldecker - biplane) The initial biplane model.
- Junkers T 23E
- (E - Eindecker - monoplane) Monoplane version eliminating the lower wing.
- Junkers T 26
- A more advanced iteration of the T 23, equipped with a 62 kW (83 hp) air-cooled Junkers L1 6-cylinder inline engine housed within a circular cowling. This modification extended the aircraft's length by 280 mm (11 in). Offered in both D and E variants, it exhibited a slight reduction in speed but nearly doubled its operational range to 345 km (214 mi). Despite these enhancements, it remained prohibitively expensive for use in flight training schools. Its maiden flight took place on 23 October 1923, with production limited to no more than 11 units.
- Junkers T 27
- A single T 26D model fitted with a more powerful 95 kW (128 hp), 9-cylinder Clerget 9Z rotary engine, which first flew in 1925.