It is used in the -60F for the sonar and hoist. I suspect that the R also uses it.
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Silencing Rotor Blades
- Thread starter mmx1
- Start date
No, it is mechanically powered off of the transmission. It is mounted back by the rotor brake.
The B has two pumps driven off the transmission and one electrically powered backup pump. The F has three pumps on the trans and one electric. (On the B there is a blanking plate on the transmission in the place of that third pump- no need for it without a reeling machine.)
With all the extra hydraulics I heard there was even an option for a Cheech & Chong low-rider style landing gear, along with chain cyclics and collectives, giant fuzzy dice, and spinning hubcaps. But the Navy had to pay for the JSF...
Do you lose anything if one of the main pumps fails, what systems does the electrical pump power, and does it go into effect automatically or does that need to be initiated by crew?
The electric pump is designed to automatically turn on and take over for the lost pump in flight. (There is some other logic in place where the system attempts to automatically islolate whatever leak may have caused the pump to fail.) It's a bit complex to write up in a post.
The simple answer is that the backup pump comes on under the 5 following circumstances:
#1 Hyd pump fail
#1 Tail rotor servo fail
#1 Hyd resevoir low
#2 Hyd pump fail
APU Accumulator low
(3 ones, a two and a poo)
Instructor pilots will tell you those are the five lights that bring on the backup pump. In actuality, the lights don't do it. The sensors that bring on those lights provide a redundant signal to the #2 logic module, which then turns on the backup pump and sets the depressurization of the pump for 3-5 seconds or .5 seconds if K4 relay is not energized (main generators online)
Bringing it back on topic..Did you know the wide chord blades have no BIM indicators? AND..no track and balance is required when replacing a tip cap of a wide chord blade!
Yeah, I know. Being a maintenance guy is pretty geeky!
#1 Hyd pump fail
#1 Tail rotor servo fail
#1 Hyd resevoir low
#2 Hyd pump fail
APU Accumulator low
(3 ones, a two and a poo)
Instructor pilots will tell you those are the five lights that bring on the backup pump. In actuality, the lights don't do it. The sensors that bring on those lights provide a redundant signal to the #2 logic module, which then turns on the backup pump and sets the depressurization of the pump for 3-5 seconds or .5 seconds if K4 relay is not energized (main generators online)
Bringing it back on topic..Did you know the wide chord blades have no BIM indicators? AND..no track and balance is required when replacing a tip cap of a wide chord blade!
Yeah, I know. Being a maintenance guy is pretty geeky!
Out of curiosity...
Does your B/U pump come on automatically w/ an accumulator low light? The Seahawks (as you may remember) have to be cycled if the accum is low.
On the ground (WOW) the automatic feature of the B/U pump (3 ones and a two) is disabled except for the accumulator low light and hydraulic leak test. In the air, the B/U pump comes on automatically under the previous conditions regardless of switch position.
In our through flight checklist, where the B/U pump is in the OFF position, turning the APU gen on after APU start results in the B/U pump coming on and recharging the accumulator, then shutting off after 90 seconds (180 secs w/dual accumulators). If you don't move the collective to full down or no more than 1" from bottom during that 90 seconds you have to turn the B/U pump on, move the controls, then turn it off again. This is not uncommon in the M model through flight checklist where you are loading COM & NAV presets, flight plans, setting up the MFDs, etc..right after turning the APU gen on. You get to engine start and realize the collective creeped up to mid position before the B/U pump shut off.
In our through flight checklist, where the B/U pump is in the OFF position, turning the APU gen on after APU start results in the B/U pump coming on and recharging the accumulator, then shutting off after 90 seconds (180 secs w/dual accumulators). If you don't move the collective to full down or no more than 1" from bottom during that 90 seconds you have to turn the B/U pump on, move the controls, then turn it off again. This is not uncommon in the M model through flight checklist where you are loading COM & NAV presets, flight plans, setting up the MFDs, etc..right after turning the APU gen on. You get to engine start and realize the collective creeped up to mid position before the B/U pump shut off.
That's the best memory aid I've heard for that!
Interesting about the third mechanically driven pump.
What effect do the new blade shapes have on blade stall?
The wide chord blades have the following characteristics:
- Increased maneuverability in hot/high conditions
- Increased lift (535 lbs at sea level)
- Increased level flight performance >19k lbs, DA > 8000'
- Anhedral droop of 20 degrees
- Inboard & outboard trim tabs
- 24.25" chord vs 21.75"
- 16.3 degrees twist
- 30 degree sweep of tip
- Carbon/fiberglass main spar with no BIM indicators
Thanks, busdriver and roblyman!