In Stock SKU: 2527

Vintage Ryan STA, 2 inch, Brass Venturi Tube

The majority of gyroscopic instruments in today's modern aircraft, particularly military and larger commercial aircraft such as the Turn/Bank, Directional Gyro and Artificial Horizon indicators rely on a vacuum generated by an independent electrical pump or vacuum pump driven by the aircraft’s main engines, but this wasn't always the case.

Early vintage aircraft instrumentation achieved their vacuum power source through the use of a simple Venturi Tube mounted on the fuselage or wind strut parallel with the longitudinal axis of the aircraft. 

The Venturi tube works on the same scientific law known as the Bernoulli effect as an airfoil.

The pressure in a stream of fluid is reduced as the speed of the flow is increased. When that fluid is air passing over the cambered upper surface of an airfoil, the result is lift. When it flows through a Venturi tube, the result is suction.

As air passes through the narrow throat of the tube, its speed increases and its pressure drops. A small port inside the constricted area taps this pressure to create suction in a line connected to the port. The line is plumbed back to the gyroscopic instruments.

With no moving parts and no power-source other than a slipstream it is still used today, as relatively inexpensive way of producing the vacuum needed to suck air into the instruments’ inlet port to spin the gyro rotor activating the instrument for smaller recreational and vintage aircraft.

It’s only downside is that it requires that slipstream to operate and is ineffective until the aircraft gains enough speed to create a flow through the tube.

Venturi tubes can be seen two of the most recognised and popular biplane aircraft - the De Havilland Tiger Moth and the Boeing Stearman.

This beautiful brass Venturi Tube, mounted on its 100yr old Mango Wood stand with a highly detailed, hand built scale model of this iconic 1930’s sports trainer aircraft would be the perfect gift for any aviation enthusiast. Together with is laminated Fact Sheet detailing the history of the instrument and the Ryan ST A it’s a fantastic original memento of a bygone era.

This Ryan STA Sports Trainer Instrument comes complete with detailed Scale Model, Mango Wood Stand & Plaque plus Printed Fact Sheet featuring photo of instrument in aircraft cockpit

Return to Ryan STA MAIN PAGE

Your Ryan STA, Brass Venturi Tube, Original Recovery Curios Warbird Collectable includes:

Original Warbird instrument
Highly detailed hand-built and airbrushed 1/48 plastic scale model of the aircraft,*
Hand-crafted and beautifully finished 100yr, Far North Queensland Mango Wood display stand
Detailed, 2-sided, printed and laminated Instrument Fact Sheet detailing aircraft and instrument
Removable Magnetic Display Arm

The 1/48 scale hand-built and airbrushed plastic model comes with a choice of two Squadron markings and camouflage.

Upon order placement you will receive an email asking for your preferred configuration.

Your complete Recovery Curios Original Instrument Collectable is securely packed and delivery normally takes between 4 - 6 weeks approx.

Did you fly or maintain a Ryan STA Sports Trainer or have a friend, colleague or family member who did? Check out our PERSONALISED ORIGINAL INSTRUMENT COLLECTABLE OPTION here.