"Superchargers low and latched"

[MachFly]

I was watching Pear Harbor the other day and I'm trying to understand one of the call outs. Just before the first B-25 started rolling (02:34:01) there was a call out "Superchargers low and latched". Does anyone know what the word "latched" means in this context?

Thanks

[Pigslilspaz]

If it's from Pearl Harbor, there is a chance they made that up, could be wrong though.

[rpm]

http://www.wingsacrossamerica.us/wasp/check_list.htm

Before take off (Pilot answers Underlined)

1. Check flying controls for free movement.
2. Cowl flops - Up
3. Wing flaps - Down 1/4 to 1/2 required.
4. Remove landing gear control lack and cock safety
        lock - removed and locked.
5. Supercharger - Low.
6. Oil Cooler shutters - Up - Except during cold weather.
7. Carburetor air - Up.
8. hydraulic pressure - 750 - 950 lbs./sq. in.
9. Booster pumps -On
10. Nose and main gear emergency control - Up.
11. Mixture Control - Auto rich.
12. Propeller Controls - high RPM
13. Propeller Switches - Automatic, Safety, Normal.
14. Batteries - On.
15. Main Inverter - On.
16. Generator main line switches. 0n.
17. Fuel Supply - Adequate.
18. Tabs - (As required).
19. Hatches - closed and satisfied.
20. Crew - In position.

[cpxxx]

Actually a quick Google for a B25 checklist revealed that one of the steps is 'Supercharger low and locked'.  Which is similar to latched, I suppose. But it's actually part of the landing checklist. Typical Hollywood!

[Shuffler]

That pearl harbor movie was all very factual


























 

[icepac]

I'm sure intrepid or stupid pilot took one off using high supercharger and managed manifold pressure with the throttles to get shorter roll.

[MachFly]

Actually a quick Google for a B25 checklist revealed that one of the steps is 'Supercharger low and locked'.  Which is similar to latched, I suppose. But it's actually part of the landing checklist. Typical Hollywood!

So what does "locked" have to do with a supercharger? Since you mentioned it's from a landing checklist, "locked" would be used for "landing gear down and locked", but that has nothing to do with a supercharger.

[Stoney]

So what does "locked" have to do with a supercharger? Since you mentioned it's from a landing checklist, "locked" would be used for "landing gear down and locked", but that has nothing to do with a supercharger.

Could be the boost control lever had some sort of mechanical lock on it to keep it from being inadvertently moved during throttle or prop lever operation.  There are some guys on this board that have B-25 time in real life.  I'm sure they can chime in.

[Shuffler]

...or reference to all the way low.

[MachFly]

Could be the boost control lever had some sort of mechanical lock on it to keep it from being inadvertently moved during throttle or prop lever operation.  There are some guys on this board that have B-25 time in real life.  I'm sure they can chime in.

I doubt it, you don't normally have locks on power levels, that's because when you want to move them fast you don't want to have to deal with any locks. Before the flight you would normally set how tight you want them to be.

[Babalonian]

I believe the proper term with superchargers is that they've "engaged", much like you engage your various gears while shifting with a manual transmition.

[colmbo]

I doubt it, you don't normally have locks on power levels, that's because when you want to move them fast you don't want to have to deal with any locks. Before the flight you would normally set how tight you want them to be.

Machfly, how much time do you have in WWII era aircraft?  Things were done differently then.

That checklist also says the reply is "up" for the cowl flaps which I'm guessing refers to the cockpit control position vs the cowl  flap which would be open, closed or trail.

[Bodhi]

Some US aircraft have friction locks on the super charger lever just like the throttle, mixture, and prop.  Not aware of a mechanical lock as most of the past stuff I worked on was without working superchargers. 

[Shifty]

That pearl harbor movie was all very factual


























 

Yep... Hammer Down! 

[MachFly]

double post