Critical Engine

[aftrburner]

This may not be the proper forum but which engine is the critical engine on the B747?

Thanks.

 

[JethroF15]

This may not be the proper forum but which engine is the critical engine on the B747?

Thanks.

The one that's on FIRE!

 

[stonewall]

The last one still running.

 

[T-REX]

The upwind #2 or #3 engine. What do I win???

 

[mushroom]

.....

 

[mrnolmts]

The upwind #2 or #3 engine. What do I win???

Eh, wouldn't it be #1 or #4?

 

[T-REX]

Eh, wouldn't it be #1 or #4?

Your probably right.

 

[D-Bo]

This may not be the proper forum but which engine is the critical engine on the B747?

Thanks.

There is no critical engine the B747. Don't fly the 74 but why would there be one? The loss of one of the outboards (1 or 4) would cause the greater thrust arm over the loss of either 2 or 3 but I don't see the loss of one outboard having a greater performance detriment than the opposite outboard.

 

[geshields]

I didn't know we had critical engines that were based on thrust on jets...

Critical Engines on jets are based on what components are lost when an engine quits...

 

[enigma]

The last one still running.

That's the way I learned it!

 

[Fliteidol]

For zero x-wind component then its either outboard (1 or 4). For any x-wind component then its the up-wind outboard.

 

[airlinepilot]

Critical engine

The upwind, outbard engine would be the most critical. A crosswind would reduce the amount of available rudder since you are using the rudder to keep the aircraft on centerline....you don't has as much available to react to an engine failure upwind. I have seen data with other Boeing 4 engine aircraft where you had to reduce the thrust on the outboards due to runway condition (wet or worse) and a crosswind. Basically you have a VMCG vs Decision speed issue....

 

[Bake]

Join Date: Nov 2004
Posts: 4
Civ/Mil: Civilian
A/C Flown: B727, B737NG, B757-200, B757-300, SF340, J31
Ratings: ATP, Student Pilot, B727, B737, B757, B767, SF340, J31
Total Time: 10,600
Posts: 4

Please tell me you are not serious?????

 

[airlinepilot]

Boeing 4 engine time

Are you suggesting what I am saying is not correct? I have spend a great deal of time flying Boeing equipment and a number of days at the Boeing plant in Seattle. This very subject has been the topic of conversation with the Boeing pilots.....I have even discussed it with Saudia 747 crews when I was upfront this them.....

 

[Uppercrust]

What is the critical engine of an F-16???

 

[ATRedneck]

What is the critical engine of an F-16???

The one in the middle?

 

[slinky]

on a four engine swept wing jet it is the upwind outboard engine. This is why you have optimum outboard thrust. The outboards will often be pulled back to a lower setting than the inboards to decrease V1.

 

[slinky]

oops did not see airline pilots post...yes he is totally correct. V1 will be based on the greater speed. This will be either vmcg or vcef based on the temp and WX conditions.

 

[GuppyWN]

I'm not sure but I do know if you lose one right after takeoff in SFO the car alarms sound for miles!

Gup

 

[Tim47SIP]

I know, I know!

What is the critical engine of an F-16???

Well, you got me on that one. Iis it the one in the middle, or is it the one in the center? Crud!

You know, I am still trying to figure out which engine on a CH47 is the critical one! :laugh:

 

[Bjammin]

The upwind outboard for the x-wind reasons stated before. Does it really make a huge difference? NO.
I don't think I have ever noticed a difference in my V1 cut training.

 

[Junkflyer]

They're all critical on a 100 flying out of the Middle East in the summer.

 

[embpic1]

They're all critical on a 100 flying out of the Middle East in the summer.

Bingo!

 

[stupidpilot]

Critical engine is more for props

The critical engine is more of a prop term because the propwash over the wing surface provides alot of the lift on that wing. So when you lose an engine on a twin you lose 80% of the lift not 50%. But a jet engine does not provide lift to a wing so its not as big of a problem if the aircraft was designed with sufficiently powerful engines. Even on 2 engines the DC-10 still climbs like a raped ape if its not too heavy.

 

[DC8 Flyer]

The critical engine is more of a prop term because the propwash over the wing surface provides alot of the lift on that wing. So when you lose an engine on a twin you lose 80% of the lift not 50%. But a jet engine does not provide lift to a wing so its not as big of a problem if the aircraft was designed with sufficiently powerful engines. Even on 2 engines the DC-10 still climbs like a raped ape if its not too heavy.

say what now?

 

[AvroGuy]

Critical engine is more for props
The critical engine is more of a prop term because the propwash over the wing surface provides alot of the lift on that wing. So when you lose an engine on a twin you lose 80% of the lift not 50%. But a jet engine does not provide lift to a wing so its not as big of a problem if the aircraft was designed with sufficiently powerful engines. Even on 2 engines the DC-10 still climbs like a raped ape if its not too heavy.

You better reread your books. Not 80% Lift, it is 80% performance. as for a jet I agree with airlinepilot. It is the Upwind outboard engine. That comes form my USAF Training in the Fat Kid...E-3 AWACS

 

[Bjammin]

Critical engine on prop planes is due to P factor more then anything. Because of gyroscopic effect the force produced by a propeller acts at 90 degrees. With any angle of attack on the airplane the force of a clockwise rotating prop acts to the starboard side of the plane. Thus if the PORT engine fails it will mean the pilot has to use more rudder to counteract the slip produced by the starboard engine thus making more drag and not as much rate of climb.

Alot of twins have counterotating props for this reason, it negates the critical engine.

 

[91100 100 set]

I'm not sure but I do know if you lose one right after takeoff in SFO the car alarms sound for miles!

Gup

Only if the FO doesn't step on the rudder when it happens.