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Throttle Settings While Taxiing

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Hello all,

I replaced my Thrustmaster T-flight HOTAS with a CH Products Eclipse Yoke and Logitech PRO Flight Throttle Quadrant. Before, when taxiing with the Thrustmaster throttle, I had to push the throttles up at around 29-30% N1 to get a 15-20kt steady taxi speed.

Now, with the Logitech throttle, I need to keep the throttle almost at idle (between 21-23% N1) to taxi, which seems more realistic, but when even at those low settings taxi speed can quickly get up to around 30 kts if I stop paying attention for a few seconds. Can someone with a similar throttle setup explain their taxi technique to me? I feel like I'm riding the brakes too hard to maintain a steady taxi speed, and my throttle setting is either too high or too low.

Thanks

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You can skip over this, as I don't have an answer to your question. I do find it a bit odd that the N1 rating for taxiing from one throttle to another would be vastly different, assuming aircraft weight and environmental factors are the same. It wouldn't be a calibration issue to me. Assuming default loadout for cargo/pax, I would say that for my Thrustmaster HOTAS X, it only requires about 23-25% to maintain speed while taxiing. At 29-30% N1, it would definitely be accelerating.

 

- Kevin Woo

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7 minutes ago, Kevin_28 said:

You can skip over this, as I don't have an answer to your question. I do find it a bit odd that the N1 rating for taxiing from one throttle to another would be vastly different, assuming aircraft weight and environmental factors are the same. It wouldn't be a calibration issue to me. Assuming default loadout for cargo/pax, I would say that for my Thrustmaster HOTAS X, it only requires about 23-25% to maintain speed while taxiing. At 29-30% N1, it would definitely be accelerating.

 

- Kevin Woo

I found that very odd too, and I'm still trying to figure out why.

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A similar threat is going on here:

I have the same "problems": low on weight it accelerates down the taxiway, but if i have some loads then it is easier to control speed.

In contrast with the B737NGX, the B747 QOTS II is a lot easier to taxi, once you have set taxi thrust and rolling, you can put throttles back to idle and the plane keeps rolling, but will slow down at an acceptable rate.  It feels more realistic than with the B737NGX.

I don't know what difference in programming PMDG-guy's have used (yes, QOTS II is a fairly recent release while the NGX is an "old" release), but i think it must be possible to implement this alwell in their NGX-product, not?

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12 hours ago, adf said:

Now, with the Logitech throttle, I need to keep the throttle almost at idle (between 21-23% N1) to taxi, which seems more realistic, but when even at those low settings taxi speed can quickly get up to around 30 kts if I stop paying attention for a few seconds. Can someone with a similar throttle setup explain their taxi technique to me? I feel like I'm riding the brakes too hard to maintain a steady taxi speed, and my throttle setting is either too high or too low.

Thanks

I callibrate my throttles via FSUIPC, there is possibility to set a wide curve for throttle in the lower power settings, it makes it a little more easier to control speed while on ground, on the other hand, while in the air it makes it more difficult as the curve is steeper then, but mostly i let the automation dot is work while airborne (except on final ...).

But you have to keep your feet near the brakes for sure when taxiing...

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You must remember that jet engines even at idle still produce a quite significant amount of thrust and it is very normal for an aircraft such as the 737 to accelerate away at idle thrust, especially at light weights. 

In short: I am not overly familiar with the 737 myself but it does not at all surprise me that it accelerates at idle. You just have to do what they do in real life and brake!

Generally speaking the technique is to allow the speed to increase to around 25kt and then make one smooth brake application to reduce the speed to around 10kt or so before allowing the speed to build back up. 'Riding' the brakes is bad practice and builds up excess heat and undue wear.

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The difference between OPs two control setups is a bit weird. One would think it wouldn't make a difference.

However, P3D and FSX is known for having a higher ground friction coefficient than in real life. This is likely to be the reason the NGX isn't accelerating on idle thrust but other planes do. Some addons compensate for this with additional code which would explain the difference. 

 

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6 hours ago, headley said:

In contrast with the B737NGX, the B747 QOTS II is a lot easier to taxi,

PMDG developed a new ground friction model for the QOTSII that takes the process outside of the box.  Similar to Simon, I set an N1 that will give me very slow acceleration and keep the taxi speed between 18-22 kts unless it's on the ramp where I keep it to 10 kts.  Light braking is all that is required once an appropriate N1 is set, and this will not heat up the brakes in the NGX the same way braking will heat up the 777 brakes.

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OK. Real input. At circa 70 tonnes, an NG will not move on it's own, but can need up to 40% to get moving. Once moving on level ground, and I still don't really know why, in hotter climates, it will keep rolling on idle but in colder climates you need a little more every now and then.

At typically full load landing weights of 62-63T, it rolls just fine and needs the odd brake application to keep in check. Once you get rid on one engine, it may need a little poke to keep momentum through turns, etc. But not much.

Hope that helps. Oh, and if choosing to single engine taxi, FFS don't try going up hill!!! Ain't going to happen and can be embarrassing.........

 

 

.....we all learn something every now and then!

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