doodlebomber

Fact sheet · updated

A CLOTHING STORY

Sheepskin in,
leather out.

The sheepskin flying jacket began as a practical answer to one problem: cold.

How cold is it up there?
A brown leather flying jacket with a thick cream sheepskin collar hanging on a wooden peg against a plain plaster wall
AI-generated image, not a photograph of a real person or place.

−56 °Chigh above the clouds

Early aircraft had open cockpits, and the higher they flew, the colder the air became. This independent guide tells how a sheepskin flying jacket was designed to keep aircrew warm, from museum collections and the physics of the atmosphere. It is about clothing, not combat.

At a glance

≈ 6.5 °C

Cooling per kilometre of height

In the troposphere temperature decreases with height, at a lapse rate of about 6.5 °C for every kilometre of altitude.

LAPSE RATE · WESTERN OREGON UNIVERSITY

−56 °C

Standard temperature above 11 km

NASA's standard atmosphere holds the lower stratosphere, from 11,000 to 25,000 metres, at about −56 °C.

STRATOSPHERE · NASA

TWO NUMBERS WORTH KNOWING

Every kilometre
gets colder.

One figure for how fast air cools as you climb,
one for how cold it gets.

IWM notes that even the new closed cockpits of the 1930s were unheated, so pilots still needed sheepskin flying clothing.

HOW COLD IS IT UP THERE?

Pick a height,
see the temperature.

Choose an altitude to see the air temperature on a standard day, worked out from NASA's model of the atmosphere. The bar shows how cold it is.

Temperatures calculated from NASA Glenn Research Center's standard atmosphere curve fits (metric). Real days vary.

Altitude cold check

Choose an altitude
Ground levelabout 15 °C

NASA's standard atmosphere starts at about 15 °C at the surface, the warmest part of the lower atmosphere.

3,000 metresabout −4 °C

In the troposphere temperature falls steadily with height. By 3,000 metres the standard model is already below freezing.

6,000 metresabout −24 °C

At 6,000 metres the model gives about −24 °C. In an unheated cockpit, that cold reaches the crew directly.

9,000 metresabout −43 °C

At 9,000 metres the model gives about −43 °C, more than 55 degrees colder than the ground.

Above 11,000 metresabout −56 °C

Above 11,000 metres, in the lower stratosphere, NASA's model holds the temperature roughly constant at about −56 °C.

Source: NASA Glenn Research Center, Earth Atmosphere Model (metric units): T = 15.04 − 0.00649 × h in the troposphere, and −56.46 °C from 11,000 to 25,000 m.

THE SHORT ANSWER

Built to beat
the cold of height.

A jacket shaped by altitude.
Three things worth knowing.

THE JACKET

Sheepskin and leather

Imperial War Museums describes heavyweight sheepskin inside for insulation and leather outside for durability, cut to stay flexible in a cockpit.

Spot an original

THE PROBLEM

Open cockpits, thin cold air

Most 1920s aircraft had open cockpits. As they flew higher, sub-zero temperatures became a pressing problem for pilots.

How cold is it?

THE NAME

Bomber crews only

By 1943, IWM says, high costs and limited supply meant the sheepskin flying jacket was limited to bomber crews, though others still found them.

In the collections
A close-up of a cream sheepskin collar, a heavy brass zip and a leather buckle strap on an old flying jacket
AI-generated image, not a photograph of a real person or place.

HOW TO SPOT AN ORIGINAL

Look at the collar,
then the pockets.

These design features come from Imperial War Museums' account of the RAF sheepskin flying jacket.

  1. A big turn-up collar

    A large sheepskin collar could be turned up in flight to protect the neck and lower face.

  2. A heavy-duty zip and straps

    A heavy brass zip cut down the wind, and buckles and straps at the cuffs and waist kept cold air out.

  3. Few or no pockets

    Originals had few pockets: crews wore uniforms with pockets underneath. IWM says replicas often add hand-warmer pockets.

  4. Whole panels or patchwork

    Early jackets used large single sheepskin panels. Later wartime ones were sewn from smaller pieces, with more seams.

IN THE COLLECTIONS

Museum pieces,
everyday style.

The RAF Museum describes the 1938 pattern sheepskin jacket as widely issued and worn by RAF aircrew, and holds an example made in 1940. Canada's Ingenium collection holds one from 1944 to 1945, with a sheepskin lining and steel zips.

IWM says the design was approved by the British Air Ministry for pilots in 1932. Its function-first design, it adds, helped make the jacket a style icon, often seen in films and popular culture.

A plain cream vintage biplane with an open cockpit standing on a grass airfield under a pale sky
AI-generated image, not a photograph of a real person or place.

Questions

Questions people ask

Why is it linked with bomber crews?

IWM says that by 1943 high costs and limited supply restricted the sheepskin flying jacket to bomber crews, though fighter pilots and other aircrew still acquired them.

Why did pilots need sheepskin?

Most 1920s aircraft had open cockpits, and air gets colder with height. Even the closed cockpits of the 1930s had no heating, so insulation was essential.

How cold is it at high altitude?

NASA's standard atmosphere model gives about −24 °C at 6,000 metres and about −56 °C above 11,000 metres, compared with about 15 °C at the ground.

Who designed the sheepskin flying jacket?

IWM credits Leslie Irvin, a former stuntman and parachute maker, who set up a factory in Letchworth, Hertfordshire, in 1926. His design was approved by the Air Ministry in 1932.

How can I tell an original from a replica?

IWM says originals had few or no pockets, while replicas often add them. Early originals also used large single sheepskin panels with few seams.

Sources

Where the facts come from

  1. Imperial War Museums: How a Hollywood stunt man invented an iconic RAF sheepskin jacket
  2. RAF Museum Collections: 1938 pattern flying jacket (object 83/U/1061)
  3. Ingenium (Canada): Jacket, flying, 1944-1945 (1992.2314.001)
  4. NASA Glenn Research Center: Earth Atmosphere Model, metric units
  5. Western Oregon University: Temperature terms, lapse rate (lecture notes)

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