The Rolls-Royce RB 145 and RB 145 R jet engines 
Development problems made the originally planned Rolls-Royce RB 153 with 1780 kp (17.4 kN) take-off thrust without afterburner not available. Rolls-Royce then offered the RB 145 with 1250 kp (12.2 kN) take-off thrust without afterburner. These engine was accepted for the unarmed experimental aircraft X1 and X2 not designed for pailoads. Six RB 145 powered the VJ-101 C X1. The RB 145 R with 1610 kp (15.8 kN) take-off thrust with afterburner increased the flight performance of the VJ-101 C X2. Two each were mounted in the swivelling engine pods on the wing ends while the two lift engines in the fuselage remained RB 145. Important for the V/STOL program was the low dry weight of both engines: 190 kg and 275 kg. 
 
 

370 x 370, 17k 
370 x 370, 21k 
380 x 320, 13k 
200 x 300, 12k 
Lift engines inlet behind the cockpit. Photo taken from the left wing. Lift engines inlet behind the cockpit. Photo taken from the cockpits right side. By moving forward the engine inlets, optimized for supersonic speed, an annular inlet opens for aditional air supply during V/STOL- maneuvers. The main engines in their swivelling engine pods in a Rolls-Royce test facility.