I'm going to bring something up here that should have come out a few posts back. You won't like it.

I've had two 28% Extra Specials, Three 28% Edge 540's, and two V-@ 28% Edge 504's. I've loaded a couple of them up to 21 pounds with smoke systens and a bunch of other useless stuff. I've never doubled up a rudder servo, and do that only infrequently on 35% planes. I've taken the time to experiment with c/g locations to determine how a plane flies best. The reason for that is because EVERY manufacturer provides an initial, or forward, C/G that let's anyone be able to fly the plane. It will not be the best c/g location, but it will be a safe one.

How did I learn that? From experience. That's something that you don't have a lot of yet, as indicated by some of what you've said in your posts, AND the way you've set up that plane. Don't blame the plane for what you don't know. That goes for any manufacturers' kits. If that is a true pirated W/H Extra, then it will fly great at 20 and 21 pounds. It won't fly like a foamie. It can't because it's been loaded up to be a brick. But it won't be snappy if the plane is set up correctly and the correct control inputs are used when it's flown. It will need to be flown faster for the available wing area to generate the extra lift for the extra weight, but a knowledgable flyer would know that. That flyer would also know that the plane would land faster because of that weight, and stall at a higher speed. They would understand the relationship of elevator/airspeed/stall speed with a forward c/g and plan for a snap if the plane got too slow or exceeded it's critical angle of attack. They would understand that a plane in true balance is easier to fly than a nose heavy one and that it will land slower and softer.

What I'm seeing more of here is a waste of a good plane and engine on an inexperienced flyer. You can change that by learning a little bit more.