Number 78 of 100 in 100: The Cessna AT-17 Bobcat 🪖
Conceptualization:
The Cessna AT-17 Bobcat, also known as the Cessna Crane in Canadian service, was a twin-engine advanced trainer aircraft developed during the late 1930s and early 1940s. Designed to bridge the gap between single-engine trainers and larger multi-engine combat aircraft, the Bobcat played a pivotal role during World War II in preparing pilots for the complexities of flying multi-engine planes. Based on the commercial Model T-50, the Bobcat was adapted for military use, to train bomber and transport pilots. Its role as a trainer made it an indispensable part of wartime pilot development programs, helping to address the urgent need for skilled multi-engine crews during the conflict.
Original Design:
Built with a wood and tubular steel frame covered in fabric, the Cessna AT-17 was designed as a lightweight, affordable twin-engine aircraft for training pilots during World War II. Powered by two Jacobs R-755-9 radial engines, the Bobcat provided essential hands-on experience for trainees, including practicing engine-out scenarios. Its straightforward construction made it cost-effective to produce and easy to repair, meeting the practical demands of wartime operations while effectively bridging the gap between single-engine trainers and larger multi-engine aircraft.
The AT-17’s low-wing configuration and fixed tailwheel undercarriage also provided stability and ease of handling, critical for beginners. The side-by-side seating arrangement in the cockpit facilitated close communication between the instructor and trainee, while dual controls ensured comprehensive hands-on learning. These features, combined with the aircraft’s modest speeds and forgiving handling characteristics, made the AT-17 an ideal trainer for pilots transitioning to more complex multi-engine aircraft.
Photo Credit: airliners.net - Marc Lehmann
Principal Designer:
The Cessna AT-17 was developed under the guidance of Dwane Wallace. He was pivotal figure in shaping the Cessna Aircraft Company during one of its most transformative periods. As the nephew of Cessna founder Clyde Cessna, Wallace brought a strong engineering background and a forward-thinking vision that helped steer the company through the challenges of the Great Depression. His leadership not only kept the company afloat during tough times but also set the stage for innovative aircraft like the Bobcat.
Wallace’s impact on aviation didn’t stop with the AT-17. He later played a critical role in the creation of iconic post-war models like the Cessna 140 series and the Cessna 207, which became staples of personal aviation. His knack for blending technical excellence with practical, cost-effective design ensured that the Bobcat met the military's training needs while cementing its place as a milestone in Cessna’s legacy of reliable and versatile aircraft.
Production Run:
Production of the Cessna AT-17 kicked off in December 1939 and ran through 1944, right in the thick of World War II. Originally adapted from the civilian Model T-50, the AT-17 became a critical twin-engine trainer for the U.S. Army Air Corps. With about 5,422 units produced, it’s clear just how valuable and reliable this aircraft was during its time.
As the war ramped up, so did production, reflecting the urgent need to train multi-engine pilots quickly and effectively. After the war ended, production stopped, and many AT-17s found new life in civilian roles or were retired altogether. The Bobcat’s production history is a testament to its importance as a workhorse of the war effort, bridging the gap between basic training and preparing pilots for the challenges of operational missions.
Evolution:
The AT-17 went through several variations during its production to meet the ever-changing needs of the military and its allies. Powered by reliable Jacobs R-755-9 radial engines, the AT-17 saw upgrades in later models like the AT-17A and AT-17B, which featured metal propellers and equipment tweaks to enhance performance. Some versions were equipped with advanced radio systems for better communications training, while others were lightened to improve handling. These changes weren’t just about keeping up with the times—they ensured the AT-17 stayed a dependable and versatile training platform, ready to handle the demands of its critical role throughout its service life.
Photo Credit: airliners.net - Fred Willemsen
Specifications:
General Characteristics:
- Crew: pilot + four
- Length: 32 ft 9 in (9.98 m)
- Wingspan: 41 ft 11 in (12.78 m)
- Height: 9 ft 11 in (3.02 m)
- Wing area: 295 sq ft (27.4 m2)
- Empty weight: 3,500 lb (1,588 kg)
- Gross weight: 5,700 lb (2,585 kg)
- Max takeoff weight: 6,062 lb (2,750 kg)
- Powerplant: 2 × Jacobs R-755-9 seven-cylinder, air-cooled, radial piston engine, 245 hp (183 kW) each
Performance:
- Maximum speed: 195 mph (314 km/h, 169 kn)
- Cruise speed: 175 mph (282 km/h, 152 kn)
- Stall speed: 63–66 mph (101–106 km/h, 55–57 kn)
- Range: 750 mi (1,210 km, 650 nmi)
- Service ceiling: 22,000 ft (6,700 m)
- Rate of climb: 1,150 ft/min (5.8 m/s)
- Take-off run: 650 ft (200 m) to 50 ft (15 m)
- Landing run: 1,400 ft (430 m) from 50 ft (15 m) with a 90 mph (140 km/h) approach speed
In Comparison to Other Aircraft in its Class:
When compared to other twin-engine trainer aircraft of its era, such as the Beechcraft Model 18 and the Avro Anson, the Cessna AT-17 Bobcat stood out as a practical and cost-effective option. Powered by 245-horsepower Jacobs R-755-9 engines, the Bobcat delivered sufficient power for multi-engine training while maintaining a manageable top speed of 195 mph. Its stall speed of 63–66 mph, coupled with forgiving handling, made it particularly well-suited for novice pilots transitioning from single-engine aircraft. The Beechcraft Model 18, with its higher maximum speed of 225 mph and all-metal construction, offered superior performance but came at a higher production and maintenance cost, making the Bobcat a more accessible choice for widespread training. Similarly, the Avro Anson, another key twin-engine trainer, shared similar performance metrics but lacked the Bobcat’s unique blend of simplicity and reliability. With its straightforward design, moderate performance envelope, and focus on training-specific features, the AT-17 solidified its reputation as a dependable workhorse for pilot development during World War II.
Performance:
Cessna AT-17 Bobcat Performance Envelope:
V-Speeds:
- V_NE (Never Exceed Speed): 195 mph (314 km/h)
- V_NO (Maximum Structural Cruising Speed): 175 mph (282 km/h)
- V_FE (Maximum Flap Extended Speed): 100 mph (161 km/h)
- V_A (Maneuvering Speed): 115 mph (185 km/h)
- V_S0 (Stall Speed in Landing Configuration): 63 mph (101 km/h)
- V_S1 (Stall Speed in Clean Configuration): 66 mph (106 km/h)
G-Load Limitations:
- Positive G Limit: +3.8 G
- Negative G Limit: -1.52 G
Performance Assessment:
The Cessna AT-17 Bobcat's performance envelope made it well-suited for its military role as a light transport, liaison aircraft, and navigation trainer during World War II. With a maximum speed of 195 mph and a cruising speed of 175 mph, it offered sufficient performance for personnel transport and supply missions over short to medium distances. Its low stall speeds of 63 mph (landing configuration) and 66 mph (clean) allowed safe operations on shorter or makeshift airstrips, while its moderate G-load limits (+3.8 G, -1.52 G) provided the structural stability needed for reliable and predictable handling. While it wasn’t built for combat or advanced maneuvers, the Bobcat’s simplicity, stability, and forgiving flight characteristics made it an invaluable workhorse for non-combat missions and essential support roles, playing a key part in the logistical backbone of military aviation during the war.
Photo Credit: airliners.net - Viktor Horst
Safety Record:
The safety record of the Cessna AT-17 reflects the challenges of its era and its role as a trainer. Incidents often stemmed from pilot inexperience or training-related risks, such as engine failures or structural issues like wing fabric separation. For example, in 1942, a crash in Vanscoy, Saskatchewan, vividly underscored the aircraft’s limits. Shortly after takeoff from Vanscoy Airport, the AT-17 encountered a structural failure at an altitude of about 100 feet. The aircraft dove into the ground and burst into flames, resulting in the tragic loss of three crew members and injuring two others. The investigation revealed that the pilot had performed unauthorized aerobatics, causing the fabric to peel off from the right wing. This overstressing led to a loss of control and highlighted the critical importance of adhering to the aircraft's operational guidelines. The incident served as a sobering reminder that while the Bobcat was reliable within its intended flight envelope, it was not designed to withstand the stresses of aerobatic maneuvers.
Despite this example, the AT-17’s safety record was comparable to other aircraft in its class, like the Beechcraft Model 18. Most incidents were tied to the high-pressure training environment rather than flaws in the aircraft itself, affirming its reputation as a reliable and forgiving trainer.
Conclusion:
The Cessna AT-17 Bobcat is a shining example of practical design meeting the urgent needs of wartime aviation. As a twin-engine trainer during World War II, it played a vital role in preparing pilots for the complexities of multi-engine operations, thanks to its reliable performance, simple construction, and forgiving handling. While its active service days are long over, the Bobcat holds a special place in aviation history. Restored examples continue to honor its contributions to the Allied war effort and the countless pilots it helped train. Today, it’s celebrated by enthusiasts as a lasting symbol of the golden age of aviation training.
Photo Credit: airliners.net - Toshiro Hara
Bibliography:
National Museum of the United States Air Force
Cessna Textron Aviation Official Website
Delaware Aviation Museum - U78 Bobcat
Wikipedia – Cessna AT-17 Bobcat
Airliners.net – Cessna T-50 Bobcat
Essco Links:
Piper PA-23 Aztec