Any tips for successful taxiing?

[Illi73]

This is a great plane. I'm having good fun flying it. But it is mostly on the ground I'm having a bit of trouble, specifically when taxiing.

I have great trouble turning right and keeping speed under control, and that with excessive braking... I still find myself more on the grass than on the taxi-ways (unless I have a bit longer bit where I don't need to turn much).

At first I was moving all throttles as one (I don't have a throttle quadrant as hardware support). Having the tail-wheel unlocked. It really turns quite slowly unless you stand on the differential break half of the time. And that's pretty literal.

Then I read somewhere that binding e.g. keyboard key 1, 2, 3 and 4 to the individual throttles (via the A2A key setup tool) and e.g. 5 to select 'all throttles'. This allows me to move two at a time, by e.g. pressing key 1 and 2 simultaneously. This is great help in boosting turn rate, but it comes with another problem: when I want to turn, I tend to speed up.

Let's say, my engines are all at 1400 rpm and I want to turn to the right. I hit '1' and '2' and push my throttle forward, so engine 1 and 2 go to 1800 rpm. I start to turn, but I'm also speeding up. If I hit 5 I will reset all throttles to equal again... but if I haven't yet finished my turn, I need to somehow manage 1+2 and 3+4 separately. Of course, I can also pull throttles BACK, so if I set all throttles to e.g. 1600 and then hit key 3 + 4, I can reduce engine 3 and 4 to e.g. 1000 rpm... but the plane will slow down to stop during my turn (or nearly so), making again my turn very ineffective. And it takes time again to get the wheels rolling. Rudder input helps a little bit, too, but mostly for fine-tuning. It's not enough to make nice smooth turns if the engines aren't set right from the start (and with 'nice smooth turns' I don't mean I need to be on the center line, but to stay on the taxiway and off the grass...)

This is of course a big plane and inertia plays a bigger role here too. It takes more of a 'push' to set it into motion and once it rolls it doesn't so quickly stop. The B377 is big, too, but it has a very useful 'steerable nose wheel' which makes that plane very responsive on the ground.

Anyway to make this long story short, on the ground I'm really struggling keeping this one under my control and OFF the grass; to keep it from standing still for half minute intervals and going too fast near turns. If anyone has good tips or ideas how I can further improve my taxiing with this plane, it would be more than welcome. What power settings do you use during taxiing? What RPMs, how do you manage the throttles if you also don't have a throttle quadrant on your kit?

[Illi73]

Just revisited the topic where I read about the throttle ( http://a2asimulations.com/forum/viewtop ... 29&t=24294 ) - didn't remember it was there / that one. On the screenshots there I see that e.g. both left engines are idling at 1000 rpm while the right are brought up to about 2000 rpm, or vice versa. I think I'll have to play around with that. I tried different combinations thus far... but maybe it takes some trial and error and more practice.

[n421nj]

I just give it enough power to get moving and use differential thrust to turn.

[Jacques]

I salute you for trying to handle the B-17 without a throttle, that would certainly be an exercise in frustration! Did I mis-read this, though. You have a hardware throttle, just not four of them? Or, you have no hardware throttle at all and must use the keypad? In either case, shift+ 6 brings up four controls for the engines, little boxes, which allow you to select one, two, three or all four engines at the same time. You could select two engines on the side opposite your turn and control them with one key stroke, and while you're making that turn select, but not activate the next team of engines to use (the two on the opposite side, or all four if you intend to taxi straight for a bit). This is how I manage to direct the beast around on the ground with just one throttle.

[A-26Invader]

Hydraulic pressure is key also. Higher PSI pressure will aid in turing the B-17 versus low pressure and the repeat of tapping the brakes reduces the pressure greatly rather than one continuous push and hold of the brakes. You can observe that on the hydraulic pressure gauge when you push and hold or just tap the brakes.

[Illi73]

I salute you for trying to handle the B-17 without a throttle, that would certainly be an exercise in frustration! Did I mis-read this, though. You have a hardware throttle, just not four of them? Or, you have no hardware throttle at all and must use the keypad? In either case, shift+ 6 brings up four controls for the engines, little boxes, which allow you to select one, two, three or all four engines at the same time. You could select two engines on the side opposite your turn and control them with one key stroke, and while you're making that turn select, but not activate the next team of engines to use (the two on the opposite side, or all four if you intend to taxi straight for a bit). This is how I manage to direct the beast around on the ground with just one throttle.

Yeah, at first I did without the throttle and that really didn't work out. I have ONE z-axis slider, which all four throttles are basically connected to. So indeed if I want to move just one, or two... I have to use the shift+6 menu to select only those that I want to control. That wasn't quite enough to keep me off the grass, however.

I just give it enough power to get moving and use differential thrust to turn.

I tried this out now... and it helps a good deal. Instead of having all props at about 1200-1400 rpm and then raising two on one side well above that (causing me to speed up way too much, having to break a lot extra), I now pull them back to 1000 rpm (which would make me slowdown to a stop, if I'd leave it at that). Then I noticed that about 1500 rpm is often enough to prevent me from stopping and giving me enough turn rate for a regular 90 degree turn. Then, I may or may not need to use my brake, depending a bit on my speed and other effects such as wind. It is now more the challenge to do this at the right moment, so I don't turn too early or late... but I guess that's practice as well. And, I manage to have engines e.g. at 1000, 1000, 1500, 1500 rpm (from left to right) with full right rudder to keep me going straight for the time being; releasing rudder makes me turn left. Gives me a bit of extra timing control. It will still take time for me to get the hang of it... but I saw nice improvement tonight.

Hydraulic pressure is key also. Higher PSI pressure will aid in turing the B-17 versus low pressure and the repeat of tapping the brakes reduces the pressure greatly rather than one continuous push and hold of the brakes. You can observe that on the hydraulic pressure gauge when you push and hold or just tap the brakes.

I'm hesitant to hold down the brake too long... I read everywhere that if you brake, you should do it in short bursts, rather than a long one. I have a feeling that may be bad for the brakes/tires? I don't know enough about it. But good to know about the hydraulic pressure as well! I have noticed it 'fills back up' from time to time while I'm taxiing if I need to brake a few times.

Thanks guys! I can go forward with this and make some improvements to my taxiing!

[DHenriques_]

I salute you for trying to handle the B-17 without a throttle, that would certainly be an exercise in frustration! Did I mis-read this, though. You have a hardware throttle, just not four of them? Or, you have no hardware throttle at all and must use the keypad? In either case, shift+ 6 brings up four controls for the engines, little boxes, which allow you to select one, two, three or all four engines at the same time. You could select two engines on the side opposite your turn and control them with one key stroke, and while you're making that turn select, but not activate the next team of engines to use (the two on the opposite side, or all four if you intend to taxi straight for a bit). This is how I manage to direct the beast around on the ground with just one throttle.

Yeah, at first I did without the throttle and that really didn't work out. I have ONE z-axis slider, which all four throttles are basically connected to. So indeed if I want to move just one, or two... I have to use the shift+6 menu to select only those that I want to control. That wasn't quite enough to keep me off the grass, however.

I just give it enough power to get moving and use differential thrust to turn.

I tried this out now... and it helps a good deal. Instead of having all props at about 1200-1400 rpm and then raising two on one side well above that (causing me to speed up way too much, having to break a lot extra), I now pull them back to 1000 rpm (which would make me slowdown to a stop, if I'd leave it at that). Then I noticed that about 1500 rpm is often enough to prevent me from stopping and giving me enough turn rate for a regular 90 degree turn. Then, I may or may not need to use my brake, depending a bit on my speed and other effects such as wind. It is now more the challenge to do this at the right moment, so I don't turn too early or late... but I guess that's practice as well. And, I manage to have engines e.g. at 1000, 1000, 1500, 1500 rpm (from left to right) with full right rudder to keep me going straight for the time being; releasing rudder makes me turn left. Gives me a bit of extra timing control. It will still take time for me to get the hang of it... but I saw nice improvement tonight.

Hydraulic pressure is key also. Higher PSI pressure will aid in turing the B-17 versus low pressure and the repeat of tapping the brakes reduces the pressure greatly rather than one continuous push and hold of the brakes. You can observe that on the hydraulic pressure gauge when you push and hold or just tap the brakes.

I'm hesitant to hold down the brake too long... I read everywhere that if you brake, you should do it in short bursts, rather than a long one. I have a feeling that may be bad for the brakes/tires? I don't know enough about it. But good to know about the hydraulic pressure as well! I have noticed it 'fills back up' from time to time while I'm taxiing if I need to brake a few times.

Thanks guys! I can go forward with this and make some improvements to my taxiing!

There is only rule concerning differential braking. NEVER use the inside brake without forward motion on that wheel.
Dudley Henriques

[Jacques]

It is really just practice... I spent a fair amount of time in and out of the weeds before I got the feel for it. Shift+ 6 can be a bit of a crazy dance, but once you have it down, you taxi at safe speeds and only tap the brake to begin the turn and/or end the turn, everything else is differential thrust.

[Snuffy]

You should probably know that the struts on the 17 were not made for pivoting on. I'd stay off the brakes more. Remember to unlock your tail wheel.

And really its not a race track, a minimal roll is all that is needed to taxi.

[Shadow95]

I'm sure most of you guys use "rudder pedals". And I'm presuming that everyone knows about using asymmetric power The easiest way I have found to control this plane when taxiing is using the "toe-brakes" for differential brake steering.
That said, in hard turns, like from the apron on to a taxiway, it may help to power up on the side opposite the turn. i.e: turning right, increase the throttles on the left engines. The trick is to use light brake pressure in the turns to avoid pivoting on one wheel.
I do this with nearly every plane that I fly that doesn't have nose wheel steering.