Question for Ginetta G15 Girl
Discussion
Hi
Had a couple of visiting Hawks today and something occurred which I have not seen before(or never noticed).
On closing down both A/C deployed the RAT would this be an auto deployment due to low Hyd pressure?
Also Would the system normally be disarmed prior to engine shutdown?
Just seemed strange I had not noticed it before and for both A/C to do the same thing
TIA
Had a couple of visiting Hawks today and something occurred which I have not seen before(or never noticed).
On closing down both A/C deployed the RAT would this be an auto deployment due to low Hyd pressure?
Also Would the system normally be disarmed prior to engine shutdown?
Just seemed strange I had not noticed it before and for both A/C to do the same thing
TIA
The Hawk has two Hydraulic systems.
HYD 1 has an engine driven pump and gives you both flying controls (Aileron, Elevator, Rudder) as well as Services (Airbrake, Flap, U/C, Wheelbrakes).
HYD 2 also has a (seperate) engine driven pump and supplies pressure for Flying Controls only.
However, HYD 2 also has a RAT (Ram Air Turbine) that will deploy when the pressure drops below a certain value (1500 psi IIRC), thus ensure that there is always a Flying Controls back up in event of engine driven pump(s) failure or in the case of total engine failure/flameout.
When the RAT is deployed it runs a constant displacement pump, so system pressure is controlled by a PCV (Pressure Controlling Valve) - the upshot being that there will be a cyclic read out of pressure on the HYD 2 gauge (between 1500 and 2500 psi) and the pump can be heard as a pulsing 'whir' above the noise of the a/c.
On shut-down, the Hawk's hydraulic system pressures are depleted by the pilot 'stirring' the stick. Given that the RAT will deploy as the HYD 2 pressure decreases, it will extend through the rear spine of the a/c for a short period until the system is completely depleted, whereupon it will retract back into its housing.
HYD 1 has an engine driven pump and gives you both flying controls (Aileron, Elevator, Rudder) as well as Services (Airbrake, Flap, U/C, Wheelbrakes).
HYD 2 also has a (seperate) engine driven pump and supplies pressure for Flying Controls only.
However, HYD 2 also has a RAT (Ram Air Turbine) that will deploy when the pressure drops below a certain value (1500 psi IIRC), thus ensure that there is always a Flying Controls back up in event of engine driven pump(s) failure or in the case of total engine failure/flameout.
When the RAT is deployed it runs a constant displacement pump, so system pressure is controlled by a PCV (Pressure Controlling Valve) - the upshot being that there will be a cyclic read out of pressure on the HYD 2 gauge (between 1500 and 2500 psi) and the pump can be heard as a pulsing 'whir' above the noise of the a/c.
On shut-down, the Hawk's hydraulic system pressures are depleted by the pilot 'stirring' the stick. Given that the RAT will deploy as the HYD 2 pressure decreases, it will extend through the rear spine of the a/c for a short period until the system is completely depleted, whereupon it will retract back into its housing.
Ginetta G15 Girl said:
The Hawk has two Hydraulic systems.
HYD 1 has an engine driven pump and gives you both flying controls (Aileron, Elevator, Rudder) as well as Services (Airbrake, Flap, U/C, Wheelbrakes).
HYD 2 also has a (seperate) engine driven pump and supplies pressure for Flying Controls only.
However, HYD 2 also has a RAT (Ram Air Turbine) that will deploy when the pressure drops below a certain value (1500 psi IIRC), thus ensure that there is always a Flying Controls back up in event of engine driven pump(s) failure or in the case of total engine failure/flameout.
When the RAT is deployed it runs a constant displacement pump, so system pressure is controlled by a PCV (Pressure Controlling Valve) - the upshot being that there will be a cyclic read out of pressure on the HYD 2 gauge (between 1500 and 2500 psi) and the pump can be heard as a pulsing 'whir' above the noise of the a/c.
On shut-down, the Hawk's hydraulic system pressures are depleted by the pilot 'stirring' the stick. Given that the RAT will deploy as the HYD 2 pressure decreases, it will extend through the rear spine of the a/c for a short period until the system is completely depleted, whereupon it will retract back into its housing.
HYD 1 has an engine driven pump and gives you both flying controls (Aileron, Elevator, Rudder) as well as Services (Airbrake, Flap, U/C, Wheelbrakes).
HYD 2 also has a (seperate) engine driven pump and supplies pressure for Flying Controls only.
However, HYD 2 also has a RAT (Ram Air Turbine) that will deploy when the pressure drops below a certain value (1500 psi IIRC), thus ensure that there is always a Flying Controls back up in event of engine driven pump(s) failure or in the case of total engine failure/flameout.
When the RAT is deployed it runs a constant displacement pump, so system pressure is controlled by a PCV (Pressure Controlling Valve) - the upshot being that there will be a cyclic read out of pressure on the HYD 2 gauge (between 1500 and 2500 psi) and the pump can be heard as a pulsing 'whir' above the noise of the a/c.
On shut-down, the Hawk's hydraulic system pressures are depleted by the pilot 'stirring' the stick. Given that the RAT will deploy as the HYD 2 pressure decreases, it will extend through the rear spine of the a/c for a short period until the system is completely depleted, whereupon it will retract back into its housing.
Thanks for that explains it nicely.Ginetta G15 Girl said:
The Hawk has two Hydraulic systems.
HYD 1 has an engine driven pump and gives you both flying controls (Aileron, Elevator, Rudder) as well as Services (Airbrake, Flap, U/C, Wheelbrakes).
HYD 2 also has a (seperate) engine driven pump and supplies pressure for Flying Controls only.
However, HYD 2 also has a RAT (Ram Air Turbine) that will deploy when the pressure drops below a certain value (1500 psi IIRC), thus ensure that there is always a Flying Controls back up in event of engine driven pump(s) failure or in the case of total engine failure/flameout.
When the RAT is deployed it runs a constant displacement pump, so system pressure is controlled by a PCV (Pressure Controlling Valve) - the upshot being that there will be a cyclic read out of pressure on the HYD 2 gauge (between 1500 and 2500 psi) and the pump can be heard as a pulsing 'whir' above the noise of the a/c.
On shut-down, the Hawk's hydraulic system pressures are depleted by the pilot 'stirring' the stick. Given that the RAT will deploy as the HYD 2 pressure decreases, it will extend through the rear spine of the a/c for a short period until the system is completely depleted, whereupon it will retract back into its housing.
How do you remember all this stuff? I forgot it by the end of groundschool, at very best the end of valley...HYD 1 has an engine driven pump and gives you both flying controls (Aileron, Elevator, Rudder) as well as Services (Airbrake, Flap, U/C, Wheelbrakes).
HYD 2 also has a (seperate) engine driven pump and supplies pressure for Flying Controls only.
However, HYD 2 also has a RAT (Ram Air Turbine) that will deploy when the pressure drops below a certain value (1500 psi IIRC), thus ensure that there is always a Flying Controls back up in event of engine driven pump(s) failure or in the case of total engine failure/flameout.
When the RAT is deployed it runs a constant displacement pump, so system pressure is controlled by a PCV (Pressure Controlling Valve) - the upshot being that there will be a cyclic read out of pressure on the HYD 2 gauge (between 1500 and 2500 psi) and the pump can be heard as a pulsing 'whir' above the noise of the a/c.
On shut-down, the Hawk's hydraulic system pressures are depleted by the pilot 'stirring' the stick. Given that the RAT will deploy as the HYD 2 pressure decreases, it will extend through the rear spine of the a/c for a short period until the system is completely depleted, whereupon it will retract back into its housing.
GGibbo said:
PaulG40 said:
'Cos she's a geek!
The aircrew have GR4 ECS and Electrical Power Generation Diagrams and the Emergency Drill Failure Notes in their bogs at our place! ECS in Trap 1, lecky in trap 2.
You must be at Lossie 'cos we have copies of Nuts and Zoo in our traps!The aircrew have GR4 ECS and Electrical Power Generation Diagrams and the Emergency Drill Failure Notes in their bogs at our place! ECS in Trap 1, lecky in trap 2.
In the pilot trap someone keeps leaving a copy of GQ in there. No one will own up to buying it!
Ginetta G15 Girl said:
HYD 1 has an engine driven pump and gives you both flying controls (Aileron, Elevator, Rudder) as well as Services (Airbrake, Flap, U/C, Wheelbrakes).
Do RAF Hawks (TMk1 and TMk2) have a hydraulic powered rudder?It certainly wasn't a feature of some of the export variants I've worked on.
The Mk63 (UAE) and Mk64 (Kuwait) both had manual rudders. The Mk102 (UAE) if I remember correctly had a hydraulic rudder PCU (Powered Control Unit) as well as hydraulic nose wheel steering.
JoeBolt said:
Ginetta G15 Girl said:
HYD 1 has an engine driven pump and gives you both flying controls (Aileron, Elevator, Rudder) as well as Services (Airbrake, Flap, U/C, Wheelbrakes).
Do RAF Hawks (TMk1 and TMk2) have a hydraulic powered rudder?It certainly wasn't a feature of some of the export variants I've worked on.
The Mk63 (UAE) and Mk64 (Kuwait) both had manual rudders. The Mk102 (UAE) if I remember correctly had a hydraulic rudder PCU (Powered Control Unit) as well as hydraulic nose wheel steering.
JoeBolt said:
Do RAF Hawks (TMk1 and TMk2) have a hydraulic powered rudder?
You are quite correct - I had forgotten that the Hawk T1 and T1A have a manual rudder. As Eccles said, they also have a castoring nosewheel and steering on the ground is by differential braking.
As for the T2 I can't say, having never been near one.
GGibbo said:
PaulG40 said:
'Cos she's a geek!
The aircrew have GR4 ECS and Electrical Power Generation Diagrams and the Emergency Drill Failure Notes in their bogs at our place! ECS in Trap 1, lecky in trap 2.
You must be at Lossie 'cos we have copies of Nuts and Zoo in our traps!The aircrew have GR4 ECS and Electrical Power Generation Diagrams and the Emergency Drill Failure Notes in their bogs at our place! ECS in Trap 1, lecky in trap 2.
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