With the introduction of new high-performance twin-engine aircraft at the U.S. Army Air Corps at the start of the Second World War in Europe it was evident that new aircraft types would be needed for advanced training of future pilots. The gap between the T-6 and types like the B-25 and B-26 bombers had to be closed with a flying course on a twin-engine trainer. Also for the new Lockheed P-38 twin-engine fighter an advanced training course on a twin-engine type was considered as necessary. Beech and Cessna already had their AT-11 Kansas and AT-17 Bobcat twin-engine trainers, but these were more suitable for crew training.
At Curtiss the design and development was started on a twin-engine advanced trainer strictly for pilot training with two-seat capacity for instructor and pilot student which had the take-off and landing characteristics of a light bomber aircraft.
Owing much of its low-wing cantilever monoplane design to the earlier CW-19 trainer, the AT-9 was a relatively small twin-engine low-wing monoplane fitted with two radial air-cooled engines. It only had capacity for two seats; entrance was on both sides with a car-type door. The main wheels retracted partially backwards into the engine nacelles and the tail wheel was non-retractable. The CW-25 was powered by two Lycoming R-680-9 radial engines.
The single CW-25 prototype acquired for evaluation was built with a welded steel-tube fuselage covered with fabric. Also wing and tail planes were fabric covered. The production AT-6 was planned to be manufactured from aluminum with a modern monocoque construction and stressed-skin wings.
The prototype AT-9 first flew in 1941 and evaluation proving satisfactory, the type was ordered into production under the designation AT-9, officially named the Fledgling, the AT-9 was almost universally known as the Jeep. The production examples differing from the prototype by being of all-metal construction.
A total of 491 AT-9s was produced and these were followed into service by 300 generally similar AT-9A aircraft. They remained in use for a comparatively short time, for the USA’s involvement in World War II in late 1941 resulted in the early development of far more effective training aircraft.
Designated at Curtiss-Wright as CW-25, the new advanced trainer received the military type designation AT-9. Initially it was named the ‘Fledgling’ but it became much more known by its later name the ‘Jeep’. The flight characteristics of the new trainer were purposely made more demanding for the student pilot. Basically it was the intention that future P-38 pilots would made their first solo flight on this fighter after a 70 hours transition training on the AT-9.
When the test flying of the CW-25 was successfully completed in 1941 the Army Air Corps ordered in total 492 AT-9 production models.
Later a final order was placed for 300 additional slightly improved AT-9A models. Main difference was a later model Lycoming R-680-13 engine with slightly more power output (300 hp), and the undercarriage retraction hydraulics were revised and improved.
The AT-9 and AT-9A was produced at Curtiss between 1941 and 1943; production of the last AT-9A was completed in February 1943. The unit costs of the AT-6 model was U.S. $44,965. The unit costs of the AT-6A dropped to U.S. $ 40,286.
Production totals:
CW-25 prototype:
1
AT-9:
41-5754 to 41-5894 (150)
41-11931 to 41-12271 (341)
AT-9A: 42-56853 to 42-57152 (300)
Total: 792 including prototype
The AT-9 and the later AT-9A was assigned from 1942 on to various military flying schools. Although it was quite demanding to fly, it was fully aerobatic and much more maneuverable that the other twin-engine advanced trainers like the AT-11 and AT-17. In spite of this, there were continuous maintenance problems and because of its more difficult flying properties it had a quite high accident rate.
Since the AT-9 could not be used for crew training its operational use was in most cases restricted to P-38 training. By the end of 1943 most AT-9’s were removed from flying status.
Since it was only a two-seater it was hardly used as a civil plane after the war when many aircraft were offered as surplus. Some were used after the war as instructional airframes at technical schools.
The U.S.A.F. Museum at Dayton Ohio has an AT-9 on display carrying the serial number 41-12150 and field registration ‘909’. It was completely restored for static display inside the museum. The Pima Air & Space Museum in Arizona has a recovered and incomplete AT-9A wreckage (serial no. 42-56882) for future restoration.
Curtiss AT 9 Fledgling
Engine: 2 x Lycoming R-680-9 radial, 295 hp (220 kW)
Wingspan: 12.29 m / 40 ft 4 in
Length: 9.65 m / 31 ft 8 in
Height: 3.00 m / 9 ft 10 in
Wing area: 21.65 sq.m / 233.04 sq ft
Wing loading: 25.83 lb/sq.ft / 126.0 kg/sq.m
Max take-off weight: 2722 kg / 6001 lb
Empty weight: 2087 kg / 4601 lb
Max. speed: 171 kts / 317 km/h / 197 mph
Cruise speed: 152 kts / 282 km/h / 175 mph
Range: 652 nm / 1207 km / 750 miles
Service ceiling: 5,791 m / 19,000 ft
Climb to 3,050 m (10,000 ft): 8.6 min
Crew: 2
All Aero 