Look up khatra, makes a world of difference.
So here's my understanding of the physics after much reading and internet scouring. Please correct me if I'm misguided.
You're a lefty, shooting thumb draw, nocking the arrow on the left side of the bow, correct?
When you shoot fingers, your fingers are very grippy and even the cleanest of release kicks the string left (for a right handed shooter) and this begins the archers paradox. Tail of the shaft goes left from the get go, then the acceleration of the string maks the shaft bend away from the riser and the rest of the paradox process ensues.
With a thumb ring, the release is so much cleaner the tail of the arrow doesnt kick away from the bow. You can force it to do this by torquing the string or using a real light spined arrow...to initiate that kick. Shooting thumbs your arrow generally travels down the bow rubbing the arrow pass most of the way and when the nock leaves the string, the arrow impacts to the left of point of aim for a lefty...right of point of aim for a righty. Nock an arrow, hold the bow toward the target without sighting doen the shaft, with the bow pointed at the target, look down the shaft and see where its pointed...that's where it wants to go when you shoot thumb draw.
There's some good slowmo vids on the internet that show the above in action.
You can google khatra and get a million different confusing vids. I'll look thru my history amd see if I can find a specific vid by a korean archer that does the best job explaining that I've come across.
For a lefty, simplified version, in the process of coming to full draw, torque your handle to the left and down. Hold that torque thru the release. Upon release the string will kick left and the bow pivot forward. This will move the handle/riser out of the path of the arrow so it can fly straight. With proper khatra arrow spine no longer matters as much. Watch the tail of your arrow, if your timing is off, or not enough khatra, the tail of the arrow hits the arrow pass and you see it kick to the side in it's flight before the fletches correct it. Nail the khatra and it flies straight and perfect.
Hope this helps and isn't too confusing. And be patient, not all of us are naturals, I've been working on thumb draw for several years off an on and still have alot of bad days.
