Junkers T 26
| Industry | Aerospace |
|---|---|
| Founded | 1895 in Germany |
| Headquarters | Germany |
The Junkers T 23 was an experimental two-seat, single-engine trainer crafted in Germany during the early 1920s. It was uniquely designed to be operated either as a parasol wing monoplane or as a biplane, facilitating direct comparison of flight handling between configurations. A total of four units were manufactured.
Design and development
Distinctive for its dual configuration capability, the T 23 could be set up as a monoplane or a biplane. The monoplane variant, designated T 23E (with "E" standing for Eindecker), employed a parasol wing design, while the biplane version, T 23D ("D" for Doppeldecker), was arranged as a sesquiplane. This model was developed as an enlarged, two-seat successor to the parasol-winged Junkers T 19, targeting the light aircraft segment and serving as an experimental platform to evaluate monoplane versus biplane handling characteristics for training applications.
In its monoplane form, the T 23 maintained construction principles similar to the T 19, featuring a duralumin tubular framework covered by corrugated metal sheets. The wing incorporated a constant chord center section with tapered outer panels and extended curved ailerons, resulting in a wingspan that exceeded the T 19’s by 2.5 m. The forward V-shaped cabane struts mirrored those on the T 19, whereas the rear struts resembled those found on the T 21. The cantilever parasol wing of the T 23E required no external bracing at the wingtips. Conversely, in the biplane T 23D configuration, the lower wing was mounted beneath the fuselage and supported by vertical V-shaped struts connecting it near its tips to the upper wing; this lower wing spanned approximately 77% of the upper wing’s length. This arrangement increased total wing area by 57% but added an additional 75 kg of structural weight.
The fuselage had flat sides and contained tandem cockpits: the front cockpit positioned beneath the leading edge for the pilot, and a second cockpit located aft under the wing, accessible through a door on the starboard side. The tailplane was mounted atop the fuselage and equipped with horn-balanced elevators; a triangular fin supported a flat-topped rudder extending between elevator cut-outs. While elevators were aerodynamically balanced, the rudder lacked such balance. The main landing gear consisted of shock-absorbing legs attached to upper fuselage longerons, reinforced by forward bracing struts and connected via a hinged axle beneath the fuselage housing both wheels. Propulsion was provided by an 80 hp (60 kW) Le Rhône rotary engine enclosed 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 configuration. Following several months of evaluation, it was converted into its monoplane form. Compared to its biplane setup, the monoplane T 23E exhibited higher take-off and landing speeds along with longer take-off runs due to greater wing loading. It also demonstrated a speed advantage of approximately 15 km/h and could transport roughly 9% more payload. Once testing was completed, all four produced units were sold to flying clubs.
Variants
- Junkers T 23D
- (D - Doppeldecker - biplane) This denotes the initial biplane model.
- Junkers T 23E
- (E - Eindecker - monoplane) The monoplane version, characterized by the absence of the lower wing.
- Junkers T 26
- A more aerodynamically optimized iteration of the T 23, equipped with a 62 kW (83 hp) air-cooled Junkers L1 6-cylinder inline engine. The powerplant was enclosed within a circular cowling, extending the aircraft's length by 280 mm (11 in). Produced in both D and E variants, it exhibited slightly reduced speed compared to the T 23 but nearly doubled its operational range to 345 km. Despite improvements, it remained financially impractical for flight training institutions. Its maiden flight occurred on 23 October 1923, with production limited to no more than eleven units.
- Junkers T 27
- A single T 26D model upgraded with a more powerful 95 kW (128 hp), 9-cylinder Clerget 9Z rotary engine, which first flew in 1925.