S 61 Sikorsky Helicopter taking off from GKT

[timmyo848]

The port (left) ECU (engine) starts first, the freepower turbine at the rear of the ECU passes through a linear actuated freewheel allowing drive to the accessorises hydraulic pumps, ac generators and transmission lubrication pump. This is called acc drive and allows the pilot to test all systems before rotor engagement such as ac power and flying controls. The stbd (right) ECU is then started taken to around 70% torque at that point the rotor brake is released and the ECU power is increased,

[timmyo848]

the difference between the two ECUs is the stbd ECU is a direct drive into the gearbox and rotors being held by the rotor brake. Once the rotor are running the port ECU is throttled back and the freewheel unit within the rear of the gearbox supplies power to the accessorises. The linear actuator is the operated from acc driver to flight driver via switch in the cockpit, the port ECU is then matched to the stbd ECU and the helicopter is ready for flight.

[carmelo580]

lol, what is that smoke at the distance?

[5695q]

Left engine starts first, with input to accessories like generators and hydrauluc pumps bypassing transmission. When right engine is started and stabilized left engine input is shifted to transmission and rotor brake is released, both engines are throttled up and spin up the rotor. The engines have a power turbine that can be held by the rotor brake at idle so when brake is released and power increased rotor spins up quick.

[bymorningslight]

I believe it is a hydraulic system that allows the turbine engines to be engaged to the rotor system and come up to speed so quickly. The rotor system has a brake (much like a disc brake on a car) on it which keeps the blades stationary until they are ready to be engaged.

[Rottmad]

beautiful helicopter

[michaelmiller85]

I'm not exactly sure what system they have, but some type of clutch that they fully engage once all the gauges are in the green.

[britishbulldoggy1]

how is it that the engine is running and the rotor isnt turning then it comes up to speed so fast?