One word: crash.

I put a heavy battery in my new L-39 jet, knowing that I would eventually upgrade to a beefier motor that could make the thrust I’d need to move the heavier battery around. I was confident that it would fly stock, even with the heavier battery, because I had seen this video of it flying with my same battery on the stock motor.

I launched it three times, and the first two times it hit the deck about 20 feet out. You’d think I’d be smart enough to quit then, but I figured I just wasn’t throwing it hard enough. So I got a running start, and gave it a good solid chuck. I got my fingers to the elevator stick just in time to pull it up and out. It flew great. Did some big long circuits on low rates. Then I went for the gusto, flipped to high rates, and pumped out a wicked fast roll. This thing rolls fast! Very nice! However, coming out of the roll, a wing dipped. I think I must have been dangerously close to the stall speed. I couldn’t recover in time and it went full throttle into the ground. Elevator was ineffective, and it was all I could do to keep the wings level as it went in. Thinking back, I should have lowered the nose to gain some air speed. These jets are very different animals since there’s no prop wash over the control surfaces to help direct the plane. I mean, there really is no prop wash at all. All control authority comes from air speed.

Damage Report:

The left wing broke and fuselage broke. But never fear. I’ve already repaired it, and I have my new motor on order.

This time I’ll wait until the new motor arrives before I try any hot shot stuff.

Here’s the flight video. Please forgive all my “dang it”s after the crash. I was a little upset, needlessly so, of course. I was fine afterwards. The whole plane only cost $99 (including fan and motor), so hey, it’s easy and cheap to repair.