Ok, as if learning to fly my sig seniorita trainer wasn't enough of a challenge, I had to go buy my son a "Zagi C" glider. It is a flying wing slope glider, basically 99% foam with servo's.

We broke the vertical fins off trying to fly without enough wind (they are very brittle on the zagi C). By the time we had enough wind, we had no fins. I've seen them without them though.

Anyway, we finally had enough wind on our slope and tried it again without the fins. This thing is very, very unstable. If you can keep it pointed directly into the wind and be VERY gentle with the controls you are OK for about 10 seconds. The second you get a puff of wind that tips a wing, it goes completely out of control and eventually spirals into the ground. From my limited experience with my powered trainer, I understand the effects of flying with the wind, stalls, etc., and I don't think I am doing anything blatently stupid.

Questions:
1) is the problem the lack of vertical fins on the ends of the wings?
2) Are these just really, really hard to fly and I just need more practice?
3) is this God's way of saying I need to lose weight, and making me run up and down the hill to retrieve our glider.

I'll go with #3.

Put the fins back. While learnign the flying wing characteristics, you need the stability. Its only the guys who have a lot of experience with the Zagi's that start trimming, and eventually remove the tip fins. (you also have to set up aileron differential if the fins atre gone... or adverse yaw will spin it every time.)

Just another 2 cents...saw one of these fly for the first time day before yesterday, windless conditions, and it shot around the sky like a dream. Am getting one this week.
As you mention having to be very gentle on the controls, the question of control throws comes to mind. The one I say had the throws set to less than 1/2 inch and was very manuverable--loops, rolls, the works.
Anyhow, just a thought.

digger

Gliderman, all planes fly like a dream, just a question of which kind...