POWER PLANTS

TYPE:

 STRAIGHT-FLOW TURBO-JET ENGINES WITH REHEAT PIPES

ENGINES:

 AVON MK 302C

THRUST:

12,580 lb (dry), 16,300 lb (reheat)

Each of the two engines is a straight-flow turbojet having a sixteen-stage  compressor driven by  a two-stage turbine. The  engines are mounted in the fuselage, with No 2 engine to the rear of and above No 1.

Systems for each engine includes, as well as associated systems;

  • High-pressure fuel system
  • Jet-pipe temperature control
  • Airflow control
  • Self-contained oil system
  • Liquid fuel starting
  • Relighting
  • Anti-icing 
  • Reheat

Starting

Each engine is started by a  liquid fuel starter, which uses the gasses from the decomposition of the fuel to drive the starter turbine, connected to the engine by a reduction gear. The starters use a common 3-gallon fuel tank installed in the fuselage spine; in ideal conditions ,a total of six engine starts may be obtained.

Pressing the starter button initiates a timed sequence of operations.

  1. The starter motor combustion chamber is scavenged by compressed air.
  2. A fuel charge is pumped into the combustion chamber.
  3. The mixture of fuel and air is ignited by two high-frequency igniter plugs.
  4. The starter turns the engine and the engine high energy ignition plugs light up the engine.
  5. When the engine reaches approximately 20% RPM the starter is shut down.

Reheat

Engine thrust may be increased by reheat (after-burning). This is achieved by injecting fuel into the jet pipe and burning the fuel in the unconsumed oxygen in the gas stream as it passes through the jet pipe. Combustion of the injected fuel raises the temperature and efflux velocity of the exhaust gas, and hence, increases the thrust.

Accessory Drives

Hydraulic Pumps - Hydraulic pressure for the flying controls and services is supplied by four pumps, two on each engine. The pumps are mounted on the external wheel-case on the port side of the compressor casing, and are secured by quick-release clamps.

Fueldraulic Pumps - An engine driven fueldraulic pressure pump is fitted on the starboard side of each engine. These pumps supply fuel pressure to drive the motors of the fueldraulic booster pumps in the aircraft fuel system.

 

FUEL CONSUMPTION

Fuel consumption remained the Lightning's Achilles heel throughout its career, effectively limiting its range. Later variants, with the addition of extra tanks had much improved range, but fuel consumption remained steady. The average car tank holds 60-70 litres of fuel, which in the lightning would last approximately 7 seconds with re-heat engaged!! though far better during cruising, such ravenous consumption rendered the lightning 'fuel critical' by the time it reached the end of the runway!  hence the requirement for flight refueling probes during combat air patrols or loiter missions.

Many comment that the 'fuel problem' should have been addressed early in its career. However there was no deficiency from an operational point of view. It wasn't until later years that the Lightning required longer range. The P1 was designed as fast interception platform that required little range for its intended use. The Lightning had plenty of range for a fast climb to meet Russian bomber incursion, and counter with missiles, before returning to base or ditching. The lightning became a multi role platform for which it was not intially designed for, only then did fuel and range become an issue.