The TH-57 Perpetual Motion Machine

[Pags]

Yes, and "AUTO".

We were talking about an FCF check that isn't done anymore by USN that required the T/R SERVO switch to be moved from norm to backup in flight, not the LDI check on deck.

 

[Gatordev]

I've had some pilots tell me that it will not make a difference, but I seem to have had less trouble with 'hung droops' than some of my contemporaries, so I think there must be a connection.

I'd argue that stirring the pot doesn't actually do anything except occasionally put the cyclic in the "right" position for the conditions. Sometimes you get weird winds or one of "those" birds where it's in a different spot, but if you just move the cyclic to the "right" spot, they'll go right in. If you don't fly a particular aircraft that much, stirring the pot is the easiest way to find the sweet spot, but you still need to hold it there. The actual stirring isn't what makes them go in.

 

[lowflier03]

A technique I was taught as a young 60 pilot (by a TPS pilot) was to lift the collective up a little (less than 1 inch) to help seat the droops stops. The other trick was to do a small stirring motion with the cyclic while the collective was up.

I've had some pilots tell me that it will not make a difference, but I seem to have had less trouble with 'hung droops' than some of my contemporaries, so I think there must be a connection.

Lifting the collective makes sense and does help. Im pretty sure this is why NATOPS used to say the 1" thing. It keeps the blades up/lighter at lower Nr, and helps lower the Nr more, thus facilitating the droops coming in without banging against the spindle stop.

 

[lowflier03]

The .5 seconds for the backup pump is for either main generator online. It is 3-5 seconds with only APU generator or external power. This is not a WOW function, it is caused by a secondary contact off of the K4 relay (which tells if either main generator is online) and the K19 relay. It determines if the depressurization valve says open to allow the backup pump to come up to speed before taking te full hydraulic load.

I always thought the time delay was the time it takes the B/U pump to spin up enough pressure to pressurize the system via the shuttle valve. (Not for the electrical system to actually swap anything over.) My understanding of the system (in navy birds at least) is that the transfer module contains a spring loaded valve so that when Pri pressure drops below the limit, the shuttle is automatically moved by the spring and lack of pressure to allow the B/U system to power it.

One of the reasons we kept going back and forth in NATOPS procedures on when to move the B/U Pump to Auto vice On or Off was that some genius suddenly thought that we might be wearing out the shuttle valves on startup during that transition phase where the main pumps were still building up pressure and the B/U pump was running, thus giving the potential for the valve to flutter or some such.

 

[Jim123]

... One of the reasons we kept going back and forth in NATOPS procedures on when to move the B/U Pump to Auto vice On or Off was that some genius suddenly thought that ...

Just goes to show that, while the metaphor, "NATOPS is written in blood!!" may be, by and large, true, it is also true that some parts of NATOPS are written in dry-erase.

 

[lowflier03]

Just goes to show that, while the metaphor, "NATOPS is written in blood!!" may be, by and large, true, it is also true that some parts of NATOPS are written in dry-erase.

Dont even get me started on that stuff. We still have procedures that are left over from the H-3 and were written based on limitations in its systems that we do not have...yet no one wants to step up and say "hey this is stupid, we should take it out."

 

[Jim123]

Dont even get me started on that stuff. We still have procedures that are left over from the H-3 and were written based on limitations in its systems that we do not have...yet no one wants to step up and say "hey this is stupid, we should take it out."

"You're only making it worse for yourself!"

 

[Gatordev]

I always thought the time delay was the time it takes the B/U pump to spin up enough pressure to pressurize the system via the shuttle valve. (Not for the electrical system to actually swap anything over.) My understanding of the system (in navy birds at least) is that the transfer module contains a spring loaded valve so that when Pri pressure drops below the limit, the shuttle is automatically moved by the spring and lack of pressure to allow the B/U system to power it.

While true, the issue was also load on the electrical system. So as it switches over, it can't demand "too much" power to spin up the pump. With the mains online, it can support the current draw, but with the lower voltage APU online, it takes longer to spool up the pump without blowing out the current limiters. I'm intentionally not putting numbers into this because I start transmorgrifying numbers between legacy birds and the Romeo (thus confusing myself) and can't keep the two straight...even though the system works the same.

I'm pretty sure you know this, but just simplifying the discussion for the cross-service "discrepancies" between series.

 

[squorch2]

To get back to the dents thing, there are currently many, many birds down because of dents in the floor and bulkheads of various compartments in the 57. There have (apparently) always been limits on the number and depth of the dents but contract maintenance for whatever reason hadn't rectified the dents. So down they go, with subsequent effects on the flight schedule above and beyond the increased number of wx cancels we're already experiencing...

GOOD TIMES.

 

[jt71582]

Watch out for the lead paint in the hangars.

 

[squorch2]

Thankfully that shit is done with. It sure was awesome hand walking NAVFLIRs all over the flightline, though.

 

[BACONATOR]

Dont even get me started on that stuff. We still have procedures that are left over from the H-3 and were written based on limitations in its systems that we do not have...yet no one wants to step up and say "hey this is stupid, we should take it out."

Just like in practice, everyone had this notion of "2 looks" on pre-flight, when it's not written ANYwhere. People just kept doing it on gouge alone, as a carry-over from the phrog. It took a STAN board to remove this faulty logic from our brains.

 

[squorch2]

Nothing wrong with more eyes on the bird during preflight.

 

[BACONATOR]

Nothing wrong with more eyes on the bird during preflight.

Agreed, but waiting another 3 minutes for someone to "hop up top for a second look" before starting up a bird for a time-critical SAR when MX swapped birds on us last minute makes no sense.

I agree with you. More looks is better. But as a RULE, it doesn't make sense, and there are times when 1 is sufficient.

 

[helolumpy]

Dont even get me started on that stuff. We still have procedures that are left over from the H-3 and were written based on limitations in its systems that we do not have...yet no one wants to step up and say "hey this is stupid, we should take it out."

Which procedure do you speak of?