I've been working hard to try and figure out this center of gravity deal. After enduring half a dozen crashes I finally got it right: I threw the airplane, the thrust was perfect, it was going just fine until... I pulled up and it went down. Thats right, my control surface orientation for my elevator was reversed. By the time I realized what had happened it was too late, and the MTP made its final landing, straight into the ground.
So if you've made changes to your airplane's control surface in anyway; your servo hookups, your control horn location, your transmitter settings, heck, every time you go to fly, just do a quick sanity check on your control surfaces, when you pull up, does your elevator go up too, etc...
I'm glad I made this mistake on a cheap airplane that could easily be rebuilt. I've got to experience these kinds of mistakes early so that as my models get more complex and expensive my simple errors will have been worked out my system.
I also learned that on a new model, put the CG a little nose heavy until you figure out where it should be, error on CG being t nose heavy. It appears that nose heavy is a lot more manageable than tail heavy, which is about as guaranteed to kill your airplane as it can get. I'm still amazing how much CG affects performance.
I also am falling out of love with Hot Glue. Its great stuff for a lot of reasons, I did entire episode on it a while back to prove that point. But, here in Arkansas, even when my model is in the trunk on my car, it gets hot enough (about 95 degrees Fahrenheit) to damage anything under some kind of pressure, where the hot glue will just fail.
I think I'll slowly move to some CA foam safe glue as I get a little better at not crashing everything I build in the first 5 seconds of my flight.