I've been wanting to build a smaller brushless copter for almost a year but hadn't had the funds, because my 5"er was taking all my attention. Now that I've got my 5"er dialed in, it's time to build a 3"er. I bought the Bonzai 130mm frame over 6 months ago and it's been sitting on my bench. I choose this frame because the main plate is 3mm, it accepts standard sized flight controllers, and looks like it will be fairly easy to build for a 3" copter.

Edit - finished up at 219 grams all up with 850mah 3s. The dal props make the motors too hot so I have some RotorX 3040 tri props in the mail. I still need to soft mount the FC and finish tuning but so far this thing is a rocket.

Edit #2 - Been loving this setup with the Turnigy Nano-Tech 850mah 3s, but I'm ready to step it up to 4s and this build can already handle it so I've ordered some RMRC 850mah 4s lipos. I also broke all of my RotorX 3040t props and have been using the much cheaper DYS 3045 tri blades for a while, they aren't as efficient as the Rotor X props but they have tons of punch and are cheap.

Here it is in action -