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NewTimer
29th Nov 2013, 19:57
Having been parked in a hospital car park for over 45 minutes near a Sea King helicopter with either an engine or APU running, a friend asked me if Sea Kings were self starting from scratch without a ground power unit.

As an aeroplane driver I can think of several reasons why you might sit for 45 minutes with the engine or APU running, and it seems unlikely to me that an aircraft capable of landing "off piste" wouldn't be self sufficient, but I don't actually know the answer!

TIA if anyone can enlighten me.

John Eacott
29th Nov 2013, 20:05
Yes, the Sea King has a big thing in the nose called a battery, which produces wiggly amps to the starter generator which turns the engine around while also sending amps to the ignitors which clack away making sparks to ignite the combustible stuff which is sprayed into the appropriate part of the Gnome.

There is no APU, but the blades & No 2 engine can be stopped and the No 1 engine runs the accessory drive train (gens and hyd pumps).

ShyTorque
29th Nov 2013, 20:12
Most, if not all helicopters can start from internal power. The reason being that helicopters don't "in the main" tend to operate from near a ground power supply.

Fareastdriver
29th Nov 2013, 20:16
What JE is trying to say is. The pilot did not know when he was going to get airborne and he wa afraid to shut down completely on the off chance that the batteriy might not be man enough to kick the engines back into life,

It's called insurance. I never bothered. I would shut down and chat up the nurses.

29th Nov 2013, 21:40
You have a choice - either keep the number 1 engine running in accessory drive to pretty much guarantee being able to get home or shut down completely and hope the battery has enough oomph to get the first engine started.

All it needs is wet or failed start and suddenly the volts are dropping quickly - we start the number one in manual control as a precaution against low voltage causing fuel computer problems.

Sometimes the choice is dictated by how long the winchman will be handing over the casualty to the hospital staff - we try to get our kit back, especially stretchers, and it may take a while for the casualty to be in a stable enough condition to be safely removed from our stretcher.

Bizarrely, we only have one battery fitted to the Mk3 and 3A when there is appropriate provision for a second one.

We do know it pisses people off listening to jet noise in the middle of the night but a. we have to make sure we can get home and stay on operational state and b. jet noise is the sound of freedom so tough!

ShyTorque
29th Nov 2013, 21:50
All it needs is wet or failed start and suddenly the volts are dropping quickly - we start the number one in manual control as a precaution against low voltage causing fuel computer problems.

This ancient technology..... :E

NewTimer
29th Nov 2013, 22:11
Exactly as I suspected. Thanks for the enlightenment.

NT

jimf671
29th Nov 2013, 22:52
... I would shut down and chat up the nurses.

Dirty work but ...

skadi
30th Nov 2013, 07:45
Bizarrely, we only have one battery fitted to the Mk3 and 3A when there is appropriate provision for a second one.

Two batteries were standard in the german Mk 41s :)

skadi

crabbbo
30th Nov 2013, 07:50
Jungly Mk 4s also have 2 batteries. However, I never had a problem starting a Mk3 or 3a on battery if you did it in manual throttle. Some crews were/are just afraid of doing this.

TorqueOfTheDevil
30th Nov 2013, 08:43
I never had a problem starting a Mk3 or 3a on battery if you did it in manual throttle. Some crews were/are just afraid of doing this.


Lucky you, but many crews have been less fortunate...ergo if you have the fuel, why take the chance of ending up stuck on the ground, unable to respond to tasking?

WASALOADIE
30th Nov 2013, 11:23
Putting the port engine into accessory drive, small amount of fuel consumption, keeps all the Hydraulic and electrical systems etc online allowing a quicker rotor start and reducing the chance of a port engine start failure and quicker reaction time in the event of another callout also reducing the chance of blocking the helipad.

GrumpyGramps
30th Nov 2013, 15:56
In my day, before reliable(?) mobile phones, it was normal to keep the port engine running on the ground to provide wiggly amps, as opposed to 24v from the battery, to enable use of the HF radio to keep in contact with ARCC.