After pushback/start engines, at idle N1 is appoximately 22%, the A/C does not move. At about 24% N1, the A/C wants to REALLY move so it does not seem to behave like a heavy A/C. All Realism sliders are at 100% per the Introduction manual. Is there anything else that can be done to have the acceleration during taxi be more like a heavy A/C ? The question is regarding acceleration and taxi speed at ~24% N1 NOT about braking (works fine). Thanks,Zach

I find the taxi performance to be spot on. What the NGX models, and other FSX aircraft fail to take into account, is the effect of inertia. Once you reach the threshold where the amount of power (N1) is sufficient to the move a heavy aircraft, inertia increases subsequent acceleration and makes it difficult to stop the aircraft simply by reducing N1 back to the threshold.

737NGThrust UseThrust use during ground operation demands sound judgment and technique. Evenat relatively low thrust the air blast effects from the large, high bypass engines canbe destructive and cause injury. Airplane response to thrust lever movement isslow, particularly at high gross weights. Engine noise level in the flight deck is lowand not indicative of thrust output. Idle thrust is adequate for taxiing under mostconditions. A maximum of 40% N1 should be adequate to initiate taxi in mostsituations. Allow time for airplane response before increasing thrust further. Break away thrust is about 35% N1.

I Have seen some jets taxi with one reverser out to keep from having to ride the brakes.

The NG ops manual mentions using rev idle when taxing during slippery conditions like ice. In the G-5/550 it's normal procedure to use rev idle during taxi. The plane will speed up quickly with idle thrust and the carbon brakes get a little grabby once warmed up. We use 1 eng in rev idle to maintain taxi speed and 2 eng in rev idle to slow prior to turns.

I Have seen some jets taxi with one reverser out to keep from having to ride the brakes.

Where?

737NGThrust UseThrust use during ground operation demands sound judgment and technique. Evenat relatively low thrust the air blast effects from the large, high bypass engines canbe destructive and cause injury. Airplane response to thrust lever movement isslow, particularly at high gross weights. Engine noise level in the flight deck is lowand not indicative of thrust output. Idle thrust is adequate for taxiing under mostconditions. A maximum of 40% N1 should be adequate to initiate taxi in mostsituations. Allow time for airplane response before increasing thrust further. Break away thrust is about 35% N1.

Some manual might have what you quoted above, but I agree with the OP.The NGX will start taxiing at 23% N1. I have to find a sweet spot around 23.5-23.8% to maintain taxi speed without losing/gaining any.At 24% N1 and higher the NGX wants to accelerate well past 20 knots. I don't load my aircraft terribly heavy but it's not terribly light either.I think this issue is what the OP was talking about, and quoting what the plane *should* do doesn't change the fact it *doesn't* do it.

I never watched my N1 while taxiing, but i can control taxi speed pretty easily without brakes or reverse thrust. I can even hold it steady by modulating the throttle.

Some manual might have what you quoted above, but I agree with the OP.The NGX will start taxiing at 23% N1. I have to find a sweet spot around 23.5-23.8% to maintain taxi speed without losing/gaining any.At 24% N1 and higher the NGX wants to accelerate well past 20 knots. I don't load my aircraft terribly heavy but it's not terribly light either.I think this issue is what the OP was talking about, and quoting what the plane *should* do doesn't change the fact it *doesn't* do it.

I believe quoting the manual on this is very good because that is where you will get the description of how Boeing says the real a/c will act.I also find the taxi behavior of the NGX to be very realistic.If you push the throttles up, you will not get an immediate response, but you will have to hold it and find that place where the NGX will begin to move, then lower the throttles to a spot that will keep the proper taxi speed consistently.It took me a while to get used to it, but now I'm very comfortable with the way the NGX taxies and I agree that it is "spot on".

Don't think I have ever been able to taxi below 30% N1, think once when I was REALLY light, but then I still had to hold at least 28-29%.

Some manual might have what you quoted above, but I agree with the OP.The NGX will start taxiing at 23% N1. I have to find a sweet spot around 23.5-23.8% to maintain taxi speed without losing/gaining any.At 24% N1 and higher the NGX wants to accelerate well past 20 knots. I don't load my aircraft terribly heavy but it's not terribly light either.I think this issue is what the OP was talking about, and quoting what the plane *should* do doesn't change the fact it *doesn't* do it.

ummm, I wasn't dis-agreeing with the OP. I just gave him the rw BBJ info from the manual for a comparison to further hi light the issue. People here are quick to give theory on the way the real aircraft behaves so I posted the fact. My post wasn't intended to change the fact that it doesn't do it nor detract from the issue.

I Have seen some jets taxi with one reverser out to keep from having to ride the brakes.

Such action could destroy the engine by hot gas reingestion, minimum airspeed usually 60 Kt for reverse thrust operation.

I never watched my N1 while taxiing, but i can control taxi speed pretty easily without brakes or reverse thrust. I can even hold it steady by modulating the throttle.

It takes more than 30% to get the aircraft to start moving, but once it is moving you drop below 25% and can keep a good taxi speed. Very small movements of the thrust levers make a difference.

It takes more than 30% to get the aircraft to start moving, but once it is moving you drop below 25% and can keep a good taxi speed. Very small movements of the thrust levers make a difference.

Not sure if you are referring to the real A/C or the PMDG NGX. My observations are quite different than yours. Per my original post, it starts moving and continues to accelerate quickly at ~24% N1.....and this is the problem. 30% N1 is take off roll numbers (only 10% below where TO/GA is activated). Again, the issue is not slowing it down (the brakes work fine). Zach

Not sure if you are referring to the real A/C or the PMDG NGX. My observations are quite different than yours. Per my original post, it starts moving and continues to accelerate quickly at ~24% N1.....and this is the problem. 30% N1 is take off roll numbers (only 10% below where TO/GA is activated). Again, the issue is not slowing it down (the brakes work fine). Zach

That's not really true. I have seen airport instructions that say to keep taxi N1 below 40%, so 30% must be used for taxi also.Using 30% to break to a roll, then pulling back is not unreasonable.