Junkers T 23
| Industry | Aerospace |
|---|---|
| Founded | 1895 |
| Headquarters | Dessau , Germany |
The Junkers T 23 was a German-built, two-seat, single-engine experimental trainer developed in the early 1920s. It was uniquely designed to operate either as a parasol wing monoplane or as a biplane, enabling direct comparison of flight characteristics. A total of four units were manufactured.
Design and development
Among a limited number of aircraft engineered for conversion between monoplane and biplane forms, the Junkers T 23 stood out. The monoplane variant, designated T 23E (E for Eindecker), utilized a parasol wing configuration, whereas the biplane version, T 23D (Doppeldecker), employed a sesquiplane layout. This model represented an enlarged, two-seat successor to the parasol-winged Junkers T 19 and was intended to penetrate the light aircraft market while facilitating experimental evaluation of handling differences between monoplane and biplane designs for training purposes.
In its monoplane setup, the T 23 incorporated construction techniques similar to those of the T 19, predominantly featuring a tubular duralumin framework covered with corrugated metal panels. The wing structure consisted of a constant chord center section flanked by tapered outer panels with extended curved ailerons; its wingspan exceeded that of the T 19 by 2.5 m. Forward V-shaped cabane struts connected the wing to the upper fuselage, while rear struts mirrored those found on the T 21. The parasol wing on the T 23E was cantilevered without external bracing at the tips. Conversely, in the T 23D biplane configuration, a smaller lower wing—measuring approximately 77% of the upper wing's span—was installed beneath the fuselage and supported by vertical V struts near its extremities. This addition increased total wing area by 57% and added roughly 75 kg to the aircraft’s structural weight.
The fuselage featured flat sides and housed tandem cockpits: the forward pilot’s seat was located beneath the wing’s leading edge, with a second cockpit positioned aft and accessible via a door on the starboard side. The tail assembly included a horizontal stabilizer mounted atop the fuselage with horn-balanced elevators; the vertical fin was triangular with a flat-topped rudder extending below into an elevator cut-out. The main landing gear comprised shock-absorbing legs attached to upper fuselage longerons and braced forward to lower fuselage points, with wheels connected by a centrally hinged axle beneath. 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 transformed into its monoplane configuration. Compared to the biplane, the T 23E monoplane exhibited increased landing and takeoff speeds along with extended takeoff distances due to higher wing loading. It also achieved roughly a 15 km/h increase in speed and could carry approximately 9% more payload than its biplane counterpart. After completing experimental trials, all four produced T 23 aircraft were sold to flying clubs for operational use.
Variants
- Junkers T 23D
- (D - Doppeldecker - biplane) This represents the initial biplane design of the model.
- Junkers T 23E
- (E - Eindecker - monoplane) A monoplane adaptation featuring the removal of the lower wing.
- Junkers T 26
- An aerodynamically enhanced iteration of the T 23, equipped with a 62 kW (83 hp) air-cooled Junkers L1 six-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 marginally reduced speed but nearly doubled its operational range to 345 km (214 mi). Despite these advancements, it remained prohibitively expensive for use by 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 95 kW (128 hp), nine-cylinder Clerget 9Z engine, which first took to the air in 1925.