Turbofan here. It seems like the general interest in commercial and general aviation flying has dwindled quite a bit, so to get something started in the Civilian forums again, I thought I might share some stuff about flying for fun in YSFS, or Commercial And General Aviation (CAGA) flying. Twice a month each month, I will be posting something about flying everything from general aviation props to heavies, and stuff I have learnt over the years (hopefully regularly, or as and when I have time on hand). I have flown basically only civilian props and jets since I discovered YSFS back in 2002, with a few exceptions when I flew a fighter jet, or an A-10 Thunderbolt. Helicopters are a different story, I haven't done much flying with those. So whatever I post-be it how to flare or how I make airports busy with air traffic-will be pertaining to civilian planes (non-VTOL). Also note that this is just stuff I have learnt over the years, and you do not have to do it this way or agree with me. Only if you want to learn how to have fun flying as close to realism as you can in YSFS without getting too technical about it.
Today's topic will be a short one: Using rapid exit taxiways in YS Flight. As you are aware, ground steering in YSFS is based on an incrementing system and is therefore not too realistic, as it does not use friction like in real life. But that's not a big deal really, because you can use the .dat file to your advantage. Basically, I found out that the value of the control variable CYAWMANE is what allows you to control the steering rate of any aircraft in YSFS. A value of 2.0 is what works for most jetliners/props, but for some aircraft, even that might be too fast of a turn rate.
Back when the excellent West Japan Map debuted, YSFS did not have as many maps with rapid-exit taxiways, and I never paid much attention to turning aircraft on taxiways. I just accepted the default assigned turn rate. Actually, for those of you new to the sim, the turn rate is actually the yaw rate, which is what controls the aircraft's turn rate while it's in the air as well. Thus, CYAWMANE is the parameter name. Anyway, to keep a long story short, I realized the ground turn rate of 5.0 was too high for me to keep a smooth transition from the runway onto the taxiway, and either I had to slow it down to 15 knots, which defeated the purpose of having a rapid-exit in the first place, or I had to exit at a non-rapid-exit. Finally, I tried Takaty's Air Do 737-400, and I was able to exit on a rapid-exit taxiway like you see in real-life videos, and that's when it gave me a clue to look in the aircraft's data (.dat) file. It took me a while but eventually I figured out that the parameter CYAWMANE was the one that controlled the aircraft's ground steering/turn rate. That also led me into further experimenting with .dat file values. Now I have configured the .dat files of all my favourite, heavily-used aircraft to where I can fly them as close to the real deal as possible, but I could keep going on and on, and this is on one topic. So, if you want to taxi at reasonable speeds and turn at taxiway intersections realistically, or use rapid-exit taxiways, set CYAWMANE to 2.0:
CYAWMANE 2.0
An additional benefit of this value is that you might find you can handle the aircraft easier during turns while in the air.
Note that the yaw stability control, CYAWSTAB does not have to be changed, unless you deem it necessary. I have it at a value of 3.0 in all my .dat files.
It will take you a while to get used to the new setting of 2.0, especially if you have used the default, which usually 5.0. Depending on the rapid-exit you are planning on using, you can exit at 30 kt or greater, although a good range would be between 30 kt and 40 kt. There is no rule of thumb for exiting runways using rapid exit taxiways, one thing I've learnt is that there is no substitute for practicing any aspect of flying. You just have to get out there and do it till you figure it out. You have to pick a spot when you'll begin turning off the runway, and use a combination of braking and turn increments so you can stick to the taxiway and not go careening off it.

Next topic I'll cover is aligning an aircraft onto a runway centerline as accurately as possible,which is actually made easier with a CYAWMANE value of 2.0.