talking with two captains of 73G/738

All I can say is those numbers are incorrect.JackColwill

Sorry, but where did you get these numbers from?? :(

All I can say is those numbers are incorrect.

Well, that's what I figured. Do you have more accurate numbers, Jack? AFAIK Airbus limits theirs to around 70% max, so I doubt pretty much you could be anywhere near full thrust "just reversed" on a Boeing TBH... Maybe I just have that feeling because you could never do that on any FS plane since FS6 or so... :(

Because the VC10 is limited to two reversers due to tail flutter, maximum reverse is rated at 93% n2!!!vololiberista

Well, that's what I figured. Do you have more accurate numbers, Jack? AFAIK Airbus limits theirs to around 70% max, so I doubt pretty much you could be anywhere near full thrust "just reversed" on a Boeing TBH... Maybe I just have that feeling because you could never do that on any FS plane since FS6 or so... :(

I've got at COA FCOM that state that if conditions absolutely require it, up to max G/A N1 can be used for reverse. It also states that you shouldn't exceed 82% N1 for pax comfort.

I've got at COA FCOM that state that if conditions absolutely require it, up to max G/A N1 can be used for reverse. It also states that you shouldn't exceed 82% N1 for pax comfort.

82% N1 is about the max yoiu will get.JackColwill

Are yu guys factoring the ram drag of a NG with 140 KTAS so you can determine the net thrust output?

No clearly not. The simple calc is static only. I was trying to make the point that even at full power (as assumed by the person I was replying to) net thrust in reverse would be much lower than he thought and unlikely to be enough to accelerate the aircraft backwards at 100+ knots.Ram drag is where a lot of reverse thrust comes from and why reverse is much less effective at low ground speed where ram drag is minimal. And of course if the aircraft was to move backwards under reverse thrust, as suggested, then ram drag is zero so does not contribute.Kevin Hall

Because the VC10 is limited to two reversers due to tail flutter, maximum reverse is rated at 93% n2!!!vololiberista

But if it's N2 where the reverse thrust is measured from, that means that all the thrust is diverted, not just the bypass. And I'm not familiar with the VC10 by it sounds like it has clamshell type reversers in this case. We were only referring to cascade reversers. However, I do not doubt your 93% N2 figure. Since thrust off the turbine is substantially lower at low altitude, I see this as very possible. To me clamshells are far more effective because during reverse operations, you don't have a forward thrust component at all. Very interesting.

You can do anything once:http://en.wikipedia...._Air_Flight_004

I was actually going to post this. You beat me to it.I think there's a disconnect here on the type of throttles everyone sees in their head, by the way.If you're thinking J41 (obviously not a Boeing), the farther you bring the levers back the more power you get on the reverse.If you're thinking Boeing, none of the Boeings I recall have a negative range. Most larger aircraft now have the main levers and reverse levers on the front. In the flare, most of the time you bring the levers back to idle, then reach forward, pull the reverse levers towards you, and then (depending on SOP) advance the throttles for reverse thrust.Here's an example from a 777:http://www.flightglobal.com/blogs/flightblogger/777-throttle-thumb-560x372.jpgAirbuses, on the other hand, have a negative range, as can be seen here on this A320:http://www.iasa-intl.com/folders/belfast/Congonhas/A320-throttles.jpgI believe the petals on the front side are there to release the lock to move into the reverse range.

But if it's N2 where the reverse thrust is measured from, that means that all the thrust is diverted, not just the bypass. And I'm not familiar with the VC10 by it sounds like it has clamshell type reversers in this case. We were only referring to cascade reversers. However, I do not doubt your 93% N2 figure. Since thrust off the turbine is substantially lower at low altitude, I see this as very possible. To me clamshells are far more effective because during reverse operations, you don't have a forward thrust component at all. Very interesting.

N2 is the engine's HP spool RPM, it does not define where the thrust reverse is measured. The Conway mixes bypass and core air in the exhaust and the whole stream is reversed when the thrust reverser is activated. IIRC this was done with internal clamshell doors, rather like some 727 thrust reversers.Kevin Hall

In the flare, most of the time you bring the levers back to idle, then reach forward, pull the reverse levers towards you, and then (depending on SOP) advance the throttles for reverse thrust.

That's not quite correct. The reverse levers are used exclusively for reverse thrust. There's a detent halfway up the reverse lever travel for idle reverse, beyond which the lever controls how much reverse thrust the engine provides with full deflection, past the second detent, being maximum reverse thrust.Here is a diagram from a 727 (I have a better one in my 737 FCOM, but don't want to post it due to potential copyright issues) I found on the internet: http://www.boeing-72...ustreverse.html

N2 is the engine's HP spool RPM, it does not define where the thrust reverse is measured. The Conway mixes bypass and core air in the exhaust and the whole stream is reversed when the thrust reverser is activated. IIRC this was done with internal clamshell doors, rather like some 727 thrust reversers.Kevin Hall

The VC10 has bucket reversers that are enclosed within the cowlings and the air is passed through a grill.vololiberista

That's not quite correct. The reverse levers are used exclusively for reverse thrust. There's a detent halfway up the reverse lever travel for idle reverse, beyond which the lever controls how much reverse thrust the engine provides with full deflection, past the second detent, being maximum reverse thrust.Here is a diagram from a 727 (I have a better one in my 737 FCOM, but don't want to post it due to potential copyright issues) I found on the internet: http://www.boeing-72...ustreverse.html

Thanks for the link. Learned somethin new today.

I wasn't aware that the thrust levers could be advanced with the reverse levers up. I thought there was some sort of interlock to prevent it?

The interlock in the FCOM refers to a position on the reverse levers at the first detent (about halfway) that prevents you from moving the reverse levers while the reverser doors are in transit. Once the reverser sleeves (doors) are deployed, the interlock disengages and you can increase the amount of reverse thrust. I believe there is another "interlock" that prevents you from moving the thrust levers while in reverse because the throttle needs to be at idle in order to to be able to move them, but this is not mentioned in the FCOM, so I can't say for sure. Maybe someone who flies a Boeing might be able to provide some input....Regardless, I would say its probably a bad idea to try to advance them while in reverse.

Just for reference, the Boeing 747 manual says: 1. Reverse Thrust Levers Control engine reverse thrust. Reverse thrust can only be selected when Forward Thrust levers are closed. 2. Forward Thrust Levers Controls engine forward thrust. Thrust levers can only be advanced when Reverse Thrust levers are down.which seems to tie in with the 727 reference.

The last post is correct. When you apply reverse thrust in the 737, you DO NOT pull the reverse levers back, and then push the thrust levers forward. Rather, the thrust levers must be at idle, and the distance in which the reverse levers are pulled determines the amount of revers thrust produced. Watch this video, it clearly shows reverse being used in an NG. Notice the aforementioned detent when the FO pulls back the RT levers, and how the thrust levers stay at idle while reverse thrust is being used. http://m.youtube.com/#/watch?desktop_uri=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3Dm2I91_-CmPE&v=m2I91_-CmPE&gl=US