So...
I build a new Tiny Trainer from scratch, I used dtfb (note the use of the acronym!) and the dry mass came out to be 180 g. The FT plans give a mass of 193 g, so I was (am) feeling good about the build. In order to get the CG correct with a 3S 850 mAh battery (80 g), I had to push the battery back such that the center of the battery was about an inch behind the leading edge of the wing. To fine tune the balance I used two stainless steel balls (total mass of 12 g) taped to a piece of fb and pushed into the tail section.
I had glide tested the plane and I got the 2nd base slide described by Piotrsko, I had practiced the hand launch with my heavier Elmer's foam board - I had to insert a couple of 1/4 inch sockets into the nose to get it to balance, but I think that I more or less had the idea after a bunch of throws. This is a link that shows
the ugly, the bad and the good.
So today I went out for a maiden flight and my hand launch was one of the ugly ones. I "think" I threw the plane forward but with an upward pitch, so it stalled, rolled over to the left and crashed on its nose - broke the prop and the firewall, so back to the bench for repairs. Next time I will bring a helper to hold the radio while I launch. At this point, I just want to get it into the air in level flight. As soon as I get that I want to bring the throttle to zero and make sure that I can land without crashing.
Each time I do this I think about Wilbur and Orville and realize that they must have been just a little bit crazy!!
Onward and upward...
p.s. Some of you might note that I can't bring myself to use the term weight when I am using the grams. I have drilled the concept of weight as w = mg into my students so many times that I can't bring myself to write "dry weight is 180 g". However, I will refrain from giving the weight in Newtons, but for those that are curious the dry weight of my plane is 1.77 N.