There has been recently again few questions about converting gliders to 2D. So I thought i will explain a bit about 2D steering and the characteristics of it. Then everyone could have a bit better understanding what do they want from glider and are they ready for it.
2D means 2-directional. That itself means that one brake, depending on how you pull it controls whether wingtip, center or both sides of trailing edge on the side you pull it.
Understanding it is very important when you decide to fly with it. Especially during landing and take-off.
When you push your hands out to the side, you will use the center part of the brakes - this is the way you want to do it to generate lift during take-off or landing. Pulling straight down engages both, but usually a bit more tips. That actually creates more drag on the tip and less lift in the center. This action makes glider actually lose a bit of lift compared to the same amount of central brakes while pushing hands out.
When you pull your hands in, you will engage tips. That is bad way to take-off and land since you 1) Decrease the lift wing is generating by reducing active surface 2) Generate drag on both tips and slow the glider down more thus losing even more lift (remember, speed=lift in neutral configuration)
Same applies for landing. (for nice long flare, you want to push hands out)
Now we are in the air and get to dynamic flying.
First, if you cannot bank your glider using weight shift, pendulum effect and engine torque and do it safely (not weight shifting on time or weight shifting to wrong side and adding too much brake might spin you), in my opinion, you should work on that before advancing to 2D. This is crucial element in safe dynamic and active flying.
Now that you have 2D, you will initiate turn with WEIGHT SHIFT, then pull tip (hands in) and soon as you bank, you shitch to center/main brake (push hands out) and counter brake the opposite side to avoid dive (again main brake with pushing hands out)
This might seem like a rocket science but actually you will get hang of it fairly fast.
yes, its easier to barrel roll with 2D but important part again is to time your weight shift.
For nice flat wingovers and spirals (also assymetric) you will use your center part anyways more (take a wrap on the main brake line to shorten that so pulling down engages center part of trailing edge more)
If you want to learn acro, then remember - acro gliders dont have 2D (and they have free-moving brakes)
So yes, you can convert your glider to 2D and for MOST gliders, it does not affect its stability given you handle it right. But the true question is - if you have beginners/intermediate glider and you are ready for 2D, maybe you should move on to next level glider? ;-) Have you mastered, what this glider has to offer?
This does not apply for higher performance gliders that you can get 2D from factory - converting these might be good option (colorado, paradox). also converting charger might be good option if you have mastered flying the serial brakes and just want agility without moving to higher performance glider.
but thats just my opinion, what its worth :-)
Btw - does enyone really reached so far reading? :-)