May have figured out proper engine shutdown

[Nealius]

Myself and a few others were having trouble getting the engines to shut down without killing the mags first, but I found out this procedure will kill the engines pretty well:

 

1. RPM to 1,000

2. Fuel selector to OFF

3. Pull cutoff lever, wait a second or so, then push it back in

4. Engine stops, turn off mags

 

With throttles to idle I found the engines choke too much and take too long to shut down. With RPM at 1,000 they stop almost instantly, with only a few backfires. 

 

 

Edited September 22, 2021 by Nealius

[Reflected]

The official procedure is:

 

1: RPM to 1200

2 (optional, unofficial): RPM to 2000 to clean the plugs

3: Pull cutouts
4: when the props stop, shut off the mags
5: Fuel selectors to OFF

 

Of course, this requires the cutouts to be fixed

[Nealius]

I'm wondering which part of the cutouts is broken. They seem to work at 1,000rpm and if you kill fuel first. Is it just the procedure order that's effed?

[Art-J]

Nah, the cutouts are valves, once they're pulled, the engine should stop simply because the fuel doesn't flow in anymore. Turning the fuel selectors to OFF is just tidying up the cockpit, because, at that stage, there's nothing flowing to the engines anyway.

 

Conversely, if you you go selector OFF first, it doesn't matter if cutout valves further down the line are implemented correctly, because there's nothing flowing to them.

 

Clearly, the cutout valves themselves don't work. Or should I say, they seem to be working only at certain position in the middle of their movement range (once the pull out animation starts, you can hear the engine cutting for a fraction of a second somewhere during their movement, but when the valve goes past that point and to the end, the engine runs again).

 

It's the same problem as with fuel pump lever in 109 - try to move it by mouse and unless you hit exactly the P1+P2 position, it won't work correctly. It only works well when P1+P2 command is bound to a key or a button... which makes me think - is it possible to bind cutouts in Mossie to keys? If so, what's going to happen if one operates them this way rather than by using mouse?

Edited September 22, 2021 by Art-J

[Nealius]

26 minutes ago, Art-J said:

is it possible to bind cutouts in Mossie to keys? If so, what's going to happen if one operates them this way rather than by using mouse?

 

You might be on to something. I have them bound to switches on my throttle base. But they still don't work unless I'm specifically at 1,000rpm and have cut fuel to that engine. If I still have the fuel to that engine, the cutoffs won't work. I don't think it's the fuel switch shutting them down, as I can wait a few seconds after turning fuel off and the engines continue running. 

[Art-J]

^ Ha, Isn't it the same with other warbirds, though? Note, there's still some fuel left in the lines between tank selector and carb / injection pump, so there will always be a bit of delay until the engine quits. Longer when it's idling, shorter when it's under power. So I'm fairly sure the selector switches alone are enough to shut them down, because that's specifically what I've been using them for ;). Works every time, even though it's not "by the book" approach.

 

I don't have the Mossie system drawing in front of me, to see where exactly the cutouts do their thing on the line between the tank and the carb to estimate how fast THEY should shut the engine, but I don't think it matters a lot. One of the first threads highlighting the cutouts operation issue was marked as "reported earlier", so I guess we'll see their operation changed in a patch or two.

Edited September 22, 2021 by Art-J

[bell_rj]

Good news! The Cut-off levers are fixed according to the patch notes (and Bignewy on Discord).

[Nealius]

1 hour ago, Art-J said:

^ Ha, Isn't it the same with other warbirds, though?

 

I don't know about the Jug or Mustang, but in the Spit if you hit the fuel cock the engine cuts out immediately. I've done it a couple times by accident while fumbling with the slipper tank.

[No1sonuk]

I just got it to shut down like this (after update):
Throttle at idle
Fuel taps off
Pull cutouts (mine are bound to the Warthog HOTAS throttle cutouts)
Turn off mags

WRT the P-51, this is what I tend to do:
Throttle to idle
MIXTURE to cutout

This is the procedure from the P-51 manual:
 

Quote

To stop the engine, follow the procedure below:
 Set the propeller control full forward. This makes the engine easier to start next time.
 Idle at 1500 RPM.
 Fuel booster – OFF.
 Move the mixture control to IDLE CUT-OFF, opening the throttle as the RPM drops below 700 RPM. Do not open the throttle above 700 RPM as any sudden opening of the throttle at this point discharges fuel into the carburetor and causes after-firing – the engine sputters and attempts to fire again.
 Ignition switch – OFF.
 Turn off all electrical switches. Don’t forget the battery switch.
 Lock the controls, and move the carburetor air lever to UNRAMMED FILTERED AIR.