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Sethos1988

Instant forward momentum after disabling reverse thrust?

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I apologise if this is a known limitation of the ESP platform, rather than the aircraft itself. I just noticed after playing around with the various features -- Yes, I shouldn't be reversing around like that  :P

 

The second you disable the reverse thrust, you don't even have to give it power, it seems to instantly shift momentum and roll forward.

 

Here's a quick GFYcat of it; https://gfycat.com/HeavenlySoulfulCod

 

I know it's not strictly within the operating procedures of the plane but I thought I'd ask.

 

 

 

Regards

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Are the engines still operating at high thrust when you go back to forward idle?

 

If so, this sort of response from the aircraft is not out of the question. There's a reason you're meant to go to reverse idle before selecting forward idle ;)

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How would one do that when using a button for reverse thrust?

 

Dave Reage

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All of my freeware planes do that - I too have a button assigned on the hotas. I just work around it... by hitting the brakes. I wonder if another button can be assigned for reverse idle? (talking generally here in FSX rather than specific to PMDG).

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At lighter weights especially, the B744 will roll forward of its own accord if you don't set the parking brake; even on a level surface.  This is due to the amount of residual thrust (jet blast) when all four engines are operating at forward idle. After landing some operators shut down No.3 engine to help reduce the need to keep applying the brakes.  Do a search for this on Youtube and you will see what I mean.

 

Bertie G 

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Even the 777 does this to some extent, probably more noticeable with the improved friction model.

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Simon has nailed it Mike. I'll try to give you an explanation as best I can based on the planes I've worked with. As you probably know, in most jets when you deploy the reverse system you do so by pulling up on the piggy back levers until they hit a detent. When that detent is hit, the physical reversing system(differs by plane)that blocks the thrust is moved into place. Once the system locks in place, you can continue to pull on the piggybacks which will accelerate the engines just as if you were pushing the throttles forward to take off.... but now the thrust is being blocked and diverted by the reversing system. If you spin the engines up to high RPM then slam the piggyback levers forward through the detents, you get quite a good shot of speed as the reversing system closes but the engines are still at higher RPM and there's nothing to divert their thrust.... it takes the engines some extra time to spool down, so they push you forward.

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it would follow that why the reversers are not programmed to keep from closing before engines reach idle. but then the scenario of aborted landing came to mind which would require immediate transition from reverse to forward maximum thrust with minimum delay, leading to OP behavior.

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then the scenario of aborted landing came to mind which would require immediate transition from reverse to forward maximum thrust with minimum delay, leading to OP behavior.

 

Nope - the cutoff point for commencing a go around/baulked landing is (on every type Im familiar with) reverse selection. Once you have selected reverse you are committed to a landing.

 

The big danger is one of the reversers not stowing which would spoil your GA very quickly.

 

I suspect there probably are more recent FADEC engines which behave exactly as you have described, just not on the Jumbo.

 

Re: handling in FS -- if you are holding down F2 (or equivalent) to increase reverse thrust to maximum, you could presumably just tap F3 a few times to progressively reduce the reverse rather than going directly to forward idle?

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