After seeing all the good rotor swaps from Human Alliance Whirl to Combiner Wars Vortex, I decided to give it a go myself. I disassembled both figures' respective rotors. I ended up flipping the blades over, and reattaching the rotor upside down on Vortex. With the help of an RC shock spacer, a 6-32 machine screw and nylock nut, I ended up with the below results. I had to drill out Vortex and recess the hole so the screw head fit flush, but it was minor surgery. I threw in a pictures in arm mode as well: No worries! The 6-32 is just the size of the screw I used. The nylock nut is just a lock nut with a nylon keeper, available at any hardware store. The spacer was just a left over from an old RC truck I had. It actually fit perfect. Here's pictures of things disassembled: Here are a couple shots with it closed and opened up: I heated up the pins with a soldering iron an then pulled them apart. The pin in Vortex I drove out with a nail. Just be careful when you pound it out. The pin in Whirl I heated and carefully pulled it apart. I think it could work well for two reasons: First, you get the blades down on his forearm where he can use it as a weapon. Second, when you fold it up, you might be able to make it an arm cannon. I think I'm going to review your thread a little more later on.. This is actually a really easy modification. You just need some patience during disassembly. The pictures I have posted already should be enough to show what I did. Here's how I did it: To take apart Vortexs rotor, I used a small finishing nail. It just fits into the hole that is in the green part of his rotor. I heated up the pin first, as this softens the plastic around it. Heat the pin for a while then tap it out with the nail and a hammer. You may need to give it a couple good hits, but it'll pop out no problem. Make sure you've got it sitting flat, and not on those little tabs used to hook into the top of the legs. It'll leave stress marks from the pounding otherwise. For Whirl, the pin can't be accessed to pound out, so I heated it for a long time, then used a needle nose pliers to wedge it apart. Again, be careful not to mess up the rotor part, but you can mangle the other piece if you need to. For Whirl, you can also just cut it out, as that piece isn't needed. All is needed is the rotor. For the spacer, because I placed the rotor on upside down, I needed the space so it would spin. You can assemble it however you like, as that's up to you. I believe gbm assembled his the normal way without a spacer and it works fine. This part is really personal preference. Because of the size of the hole in Whirls rotor, I went with a #6-32 machine screw and lock nut. Depending on what kind of screw you use, you may have to make some room under that flap on Vortex. I drilled the hole out to fit the screw, and then just used the tip of a 1/4" drill bit to sort of countersink the hole and things fit fine. Also, you may need to cut the screw to length. I know I did, but I just used one I had laying around. Then it's just touching up the paint to hide the nut and you're good to go. Good luck! It's always a plus when you don't have to find something special for an easy modification. Reusing the pin from Whirl eliminates the need for nuts and bolts.