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S61 - Hands on SSLs?

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S61 - Hands on SSLs?

Old 16th Sep 2016, 16:45
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S61 - Hands on SSLs?

Been curious about this for a while - why during takeoff/landing/hover in an S61/Sea King does the Pilot not flying hold the speed selector levers? My Sik experience is predominately H60 and we only guard the PCLs during ECU/DEC lockout operations and some maintenance checks.

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Old 16th Sep 2016, 16:58
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We didn't on the SK - no need. The S61 has a different throttle control system which I seem to remember was less automated than the SKs.

Last edited by Al-bert; 16th Sep 2016 at 21:00.
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Old 16th Sep 2016, 17:19
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The call in the event of an Engine out was "both SSLs fully forward" to maximize the NR before identifying the failed engine. After VTOSS (67 knots from 30+ year ago memory) gear up and climb then clean up the failed engine.
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Old 16th Sep 2016, 19:29
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tourque matching and droop compensation
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Old 16th Sep 2016, 22:49
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No such thing on SK.

S61 is a totally different matter. Required for Nr trimming on final approach due to a previous generation FCU, wasn't it? Bloody nuisance too when you had to complete a highly complex multi (perhaps 20) sector, multi pax/bags/freight inter/intra loadsheet to boot and figure out the implications for limited decks/limiting weights and fuel opportunities.

All in the only 90 seconds you had...

It weren't easy. Made manual jumps in the SK look like a doddle.
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Old 17th Sep 2016, 04:53
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Oh I remember that, "Speed selects fully forward not to exceed 106%". HA who needs FADECs when you had a full autonomous copilot LOL.

The engine governing system on the engines was very basic compared to nowadays, it would govern within a very narrow band and a pilot was always watching the NR to tweak up and down as required. Once in forward flight or in the hover it stabilised and didn't need much help.

Wow that brings back some memories, hopefully correct memories.

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Old 17th Sep 2016, 07:45
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To distribute the total torque requirements of the main transmission the NR has to change with increasing Tq. The S61 'droops' thus providing the necessary change of FCU datum. Moving the SSL's forward shifts the system datum thus compensating for 'droop' and at the same time increasing the rotor inertia - a good thing during take off and landing Cat A.

The SK's RR Gnomes use computer controlled FCU with electronic 'anticipators' connected to the collective so that as power is increased via the collective the computer datum is also raised. Torque sharing is again based on the need for a moving datum*, one that changes with collective position but this time it happens to go up rather than down as with the old CT58 hydro mechanical system.

*With the technology available to the S61 engine designers at the time (1950's) the problem of equalisation of engine output was one solved by scheduling each engine's torque output in line with a descending Nr. If you try it with a constant Nr datum then neither engine will be able to decide whether to add power or reduce power.

That's as best I can recall from the SK course in January 1970. :-)

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Old 17th Sep 2016, 11:46
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During the airline hiring boom of the mid 1980s an S61N pilot went for a sim assessment; given an engine failure on the take off roll he reverted to type and called for both speed selects fully forward. Doesn't really work well in a B767 at 80kt....
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Old 17th Sep 2016, 17:02
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You didn't the Coey to sit around all day while drawing huge piles of money doing nothing to earn it now would you?
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Old 17th Sep 2016, 17:42
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I have been told that during Heli-logging ops the copilot was a very busy person.
Perhaps someone who has do it can comment.
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