|Preserved Bristol Thor|
|National origin||United Kingdom|
|Manufacturer||Bristol Aero Engines|
|Major applications||Bristol Bloodhound|
The Bristol Thor, latterly Bristol Siddeley BS.1009 Thor, was a 16" diameter ramjet engine developed by Bristol Aero Engines (later Bristol Siddeley Engines) for the Bristol Bloodhound anti-aircraft missile.
Although Bristol Aero Engines acquired ramjet technology from the US company Marquardt, BAE put considerable effort into developing the Thor unit, including the construction of a high altitude test plant (HATP) at their Patchway site, with a supersonic test cell.
- BT.1 Thor
- BT.2 Thor
- BT.4 Thor
- BS.1009 Thor
Specifications (BT.2 Thor)
Data from 
- Type: Ramjet
- Length: 103.9 in (2,639 mm)
- Diameter: 15.75 in (400 mm)
- Dry weight:
- Maximum thrust: (BT.1) - 5,275 lbf (23 kN) at M2.0 at sea level
- Specific fuel consumption: 2.5 lb/lbf-hr (254.84 kg/kN-hr) at full thrust at sea level
- Power-to-weight ratio: 1.2
- Taylor, John W.R. FRHistS. ARAeS (1962). Jane's All the World's Aircraft 1962-63. London: Sampson, Low, Marston & Co Ltd.