Well, here were the specs: 66" ntn, shooting for 35lb at 28", hickory with red oak tip overlays because they're cheap and what I had sitting around for scrap. It was 1.5" wide all the way to the lever fades, which were closer to 2/3rds working limb, 1/3 lever. The levers were about 3/8ths of an inch wide, and I was planning on taking them down to about 1/2 an inch thick or so. However, I never got to the final stages of finishing. While I was pulling it on the tillering tree... Well, you can see for yourself.
Looks like a tension break to me.
I definitely paid the price for a few mistakes.
First, I should have backed it.
Second, I should have made it wider.
I'm not sure if the stiffness in the lower fade killed it or not, but the lower limb WAS the one that broke, so that might just have been it. It was also a board bow. I had hoped the grain would hold up, but that didn't work out.
I'm not sure how I'm going to break this to my friend.
EDIT: looking back, the lower limb looks a bit hinged. I should have caught that sooner.