DOUGLAS AE-1 SKYRAIDER OUTSIDE AIR TEMPERATURE (OAT) GAUGE

When the Douglas Skyraider first entered operational service with the US Navy in 1946, issues concerning wing icing did not arise until its deployment during the Korean War, where due to the extreme cold, the high speed ground attack aircraft found itself restricted to low altitudes to avoid the dangerous phenomenon. A solution was needed quickly.

During WWII, inflatable de-icing boots were fitted along the leading edges of many USAAF bombers such as the high altitude B-17 and B-29 but the system had never really been investigated for single engine high speed fighters such as the Douglas Skyraider.

Knowing the outside air temperature does not on the face of it, seem all that important but to a pilot, it provides the information necessary to make true airspeed and altitude density calculations essential to flight planning and aircraft fuel consumption.

The OAT gauge also serves as a critical early warning to potential icing conditions. Changes in altitude and passing through cloud or precipitation can cause the rapid formation of ice on the wing surfaces that can have dramatic effect on flight surfaces and aircraft stability.

At outside temperatures of between zero and minus 10 C the pilot is likely to encounter ‘clear icing’ where a glossy, thin and transparent layer of ice forms slowly over the wing surfaces reducing clean airflow over the wing increasing drag and reducing lift.

As OAT falls further, Rime ice can form which is a rougher and faster forming ice trapping air pockets which reduce air flow and further increases drag. At higher altitudes in extreme conditions, rough Mixed ice can also form which will dangerously impact the aircraft’s aerodynamics.

As ice formation is difficult for the pilot to see from the cockpit, its often called the silent creeper in aviation circles and without keeping an eye on the OAT, the first thing a pilot might experience is significant loss of wing lift resulting in a sudden stall which may be difficult to recover from.

BF Goodrich were tasked with developing a low weight, low profile de-icing system for the Skyraider and within a couple of months, flight testing had been completed on a new system incorporating of a series of small low-profile rubber tubes, activated by twice the conventional air pressure and cemented to the wings supplemented by the traditional screwed on fairing strip. 

The rubberised ‘boots’ were then inflated via a simple solenoid operated, engine driven air pump.The Skyraider was set to go.

The upper illustration shows a leading edge boot as it is held against the leading edge contour (normal in-flight condition). The lower illustration shows a leading edge boot in an inflated condition; the boot is typically in this position only for a short time to remove an accumulation of ice.

Installed at the upper right of the Skyraider’s flying panel just above the aircraft’s combined Fuel/Oil Pressure gauge, the Free Air or Outside Air Temperature (OAT) indicator alerted the pilot to the outside air temperature

This is an extremely rare, original cockpit instrument from one of the last propeller-driven fighter/bombers used by the USN.

Manufactured by the Lewis Engineering Company, this MS28008, this Outside Air Temperature cockpit indicator (OAT) comes complete with its 100yr old mango wood display stand and highly detailed 1/72 or super detailed 1/48 scale model mounted above on its magnetic arm.

Complete with its detailed laminated Fact Sheet, this Recovery Curios Original Vintage Aircraft Instrument Collectable would make an unforgettable and highly prized gift for any aviation enthusiast. 

This Douglas Skyraider Instrument comes complete with detailed Scale Model, Mango Wood Stand & Plaque plus Printed Fact Sheet featuring photo of instrument in aircraft cockpit. 

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