Engines and fuel

The Su-27 has two turbofan engines with afterburners. You fly them with one throttle that moves both together.

#Starting up

There is no engine start to do. Every time you spawn or respawn, the engines are already running at idle. There is no battery, generator or starter to work, and the ENGINE START panel on the left console has no working switches. Its START lamps light when an engine has run down, for example out of fuel.

The engines can't be shut down either: they keep running as long as there is fuel and they are not destroyed.

#The throttle

The throttle moves at 40% a second, so idle to full afterburner takes 2.5 seconds. On the left console you can watch it slide past three marks:

The SYS page on the displays shows the throttle as a percentage.

#How the engines respond

• They take time. From idle the engines take about 3 seconds to reach 90% rpm and about 4.5 seconds to reach 96%. Spooling down, they lose the first 20% in about 2 seconds.
• The afterburner lights only near full power. Push the throttle past MIL (85%). Once the engines reach about 96% rpm, the afterburner lights after a short delay, about 0.7 seconds, with a thump you can hear. It then builds up to full thrust over about a second. From idle, the afterburner lights about 5 seconds after you push the throttle all the way forward.
• The afterburner is stepless. Anywhere between MIL and MAX gives you part afterburner.
• Altitude changes everything. Thrust falls as the air gets thinner, and so does the fuel burn. Speed helps: the engines give more thrust the faster you go.

#Fuel

How fast you burn it, roughly, with both engines, standing at sea level:

Flying fast at low level burns more: full afterburner at Mach 0.9 is nearer 38 tonnes an hour. Up high the burn is much lower, so climb for range. The SYS page shows your fuel, the burn right now and how many minutes that leaves you.

#Running low

• Below 1,000 kg (2,200 lb) the LOW FUEL lamp lights and a chime sounds once.
• When the tanks run dry, both engines wind down and give no thrust. The controls still work, so glide to the nearest runway. The engines come back by themselves after refuelling.

#Leaks

A hit can hole a tank, and the fuel leaks out. Losing a piece of the jet loses the fuel inside it. Keep an eye on the fuel after taking damage.

#Refuelling and rearming

The ground crew refuel you on the ground, from the WPN page of the displays:

1. Land and come to a complete stop. The crew won't work on a moving or crashed jet.
2. On the WPN page, use FUEL up and down to choose the load, in steps of a quarter of the tanks. You can take fuel off as well as on.
3. Wait. It takes a few seconds plus the time to pump the fuel. If the jet moves, the crew stop.

The same page lets the crew load missiles: see Displays.

#Engine fire and damage

• A hit on an engine can set it on fire. The FIRE L or FIRE R lamp lights.
• There is no fire extinguisher. A fire destroys its engine in about 40 seconds, and then the rear of the jet.
• A damaged engine gives less thrust, and a destroyed one none. The Su-27 flies on one engine, so you can still limp home.