Bristol Type 138.C - High Altitude Reconnaissance Aircraft 1939

[RAFF-35]

The Bristol Type 138 was conceived as a cutting-edge research aircraft designed to explore the limits of high-altitude flight. Developed by the Bristol Aeroplane Company in the 1930s, this single-engine, low-wing monoplane was a remarkable feat of aeronautical engineering.

On 30 June 1937, the aircraft secured its place in aviation history when it reached an altitude of 53,937 feet (16,440 m) during a 2¼-hour flight, setting a world altitude record. This achievement was not only a triumph for Bristol but also to the research conducted by the Royal Aircraft Establishment (RAE) and the National Physical Laboratory, who fine-tuned the aircraft's aerodynamics and developed a functional pressure suit to sustain the pilot at extreme altitudes.

The aircraft's wooden airframe was designed to be as lightweight as possible, using a plywood skin bonded to mahogany longerons and struts. To further minimize weight, the design featured a fixed undercarriage, which was more beneficial than a retractable alternative due to the extreme altitudes at which the aircraft operated.

With war looming over Europe, the success of the Type 138's high-altitude capabilities did not go unnoticed. Australian business man Sidney Cotton, who was working with the British intelligence service MI6, recognized its potential for strategic reconnaissance, especially in an era where aerial intelligence was still in its infancy.

After the interception of a Lockheed Hudson that had been performing clandestine reconnaissance over Nazi Germany, it became evident that a new type of aircraft was needed—one that would prove impossible to intercept. Two competing solutions emerged:

The first design was the Supermarine Spitfire PR.1, which relied on speed and maneuverability.
The second was the Bristol Type 138C, which would depend on extreme altitude.
In 1938, a single Type 138B airframe was modified into the Type 138C, optimized for high-altitude photographic reconnaissance. It was fitted with a new Bristol Pegasus XX-HPS engine, equipped with a powerful two-stage supercharger capable of delivering 975 horsepower. This enhanced powerplant allowed the 138C to reach speeds of 224 mph and an operational ceiling of over 56,000 feet, surpassing any contemporary aircraft in terms of altitude.

For its reconnaissance role, the 138C was equipped with a trimetrogon rig of F24 cameras with 20-inch lenses, positioned just behind the cockpit tub. Additional fuel tanks were also installed, extending the aircraft's range to 1,247 miles.

By 1939, five Bristol 138Cs had been secretly constructed for MI6, which initially operated them under   Heston Flight, the secretive unit responsible for aerial intelligence-gathering. Shortly thereafter, the unit was absorbed into No. 1 Photographic Development Unit (PDU), the RAF's burgeoning reconnaissance wing.

From the outset of World War II, the Type 138C proved invaluable. Operating from RAF Benson and other secret locations, these aircraft embarked on high-altitude intelligence missions over Nazi-occupied Europe. Throughout 1939 and 1940, they played a key role in monitoring the build-up and movements of Axis forces, providing intelligence that shaped British strategic planning.

Missions were typically flown at altitudes between 25,000 and 30,000 feet, which was sufficient to evade most Luftwaffe fighters of the time. However, when under threat of interception, the 138C could climb beyond 35,000 feet, placing it far beyond the reach of enemy aircraft.

The use of high-altitude reconnaissance was still in its infancy, but the Bristol 138C helped lay the foundation for what would become modern strategic aerial reconnaissance. The unit operating the aircraft evolved over time, eventually becoming No. 1 Photographic Reconnaissance Unit (PRU).

The work of pioneers such as Sidney Cotton,  who had outfitted civilian aircraft for reconnaissance missions, further advanced British aerial intelligence. Cotton's innovations—such as the trimetrogon camera mount and heated cameras to prevent fogging—were incorporated into the 138C's design, making it one of the most advanced reconnaissance platforms of its time.

By 1941, the RAF had fully embraced photographic reconnaissance, with No. 1 PRU at RAF Benson leading the effort. The intelligence gathered by the 138Cs and their successors contributed significantly to the war effort, from planning the Battle of Britain to mapping targets for the Allied bombing campaigns.

Despite its critical role in the early war years, the Bristol Type 138C remained a classified asset, its missions largely unknown to the public. As more advanced aircraft such as the Spitfire PR variants and the de Havilland Mosquito PR types entered service, the 138C was gradually retired.

[Old Wombat]

Kit's going to love this one!

[PR19_Kit]

Kit's going to love this one!

You BET I do, and the backstory as well. 

Were the 138Cs pressurised as well?

I wish Dad was still alive, I'd have asked him if he was ever on them too. 

[NARSES2]

That's come out well   

[RAFF-35]

Kit's going to love this one!

You BET I do, and the backstory as well. 

Were the 138Cs pressurised as well?

I wish Dad was still alive, I'd have asked him if he was ever on them too. 

They relied on the special pressure suits that were rated to 80,000ft. Oooh cool, what did your dad do?

[PR19_Kit]

They relied on the special pressure suits that were rated to 80,000ft. Oooh cool, what did your dad do?

Took pics of Germany and the Middle East from 35000 ft or so. 

[Glenn Gilbertson]

Really good modelling & a plausible story!

[Dizzyfugu]

Nice, and great paint job, too. 

[su27rules]

   Nice!!

[buzzbomb]

very good

[The Rat]

Lovely job on both model and story! Got a part-built one somewhere in the basement, one of these days...

[SPINNERS]

Very good backstory and model - love the scheme!

[Wardukw]

I like that ...lovely bit of work   

[RAFF-35]

Very kind words everyone. Thank you very much, it means a lot!

[RAFF-35]

Lovely job on both model and story! Got a part-built one somewhere in the basement, one of these days...

Ooooh interesting, what're you planning to do with yours?