I'll use the cheap RCTimer 30A ESCs reflashed with Rapid ESC firmware...this firmware was created to enhances the multirotors performance. Not only the RCTimer can be reflashed but also Hobbyking, Turnigy, Mistery, etc... just google "Rapid ESC" to know more about it.
Just started my build. Very easy to build. I am awaiting my Parts from HK.Com
I will be using
Motors:Turnigy D2836/11 750KV Brushless Outrunner
ESC: Hobbyking SS Series 35-40A ESC
Props: 11x4.7 Props
Controller: Ardupilot 2.0
Well here is the sketchup virtual build. You can use it to make changes. I didn't put the dimensions as it's easy to get them, but they are correct from the plan. The propellers (CW or CCW) are in the same position as the video.
Motors dimensions are for DT 750 (The mount should be correct even though I didn't have one to measure)
Well I Can't insert the sketchup file (CAD) so if a moderator tells me how to send it to him so he can insert it, that would be good.
Think about it. In the H-quad, the motors are in the exact same positions than on an X-quad. It's just the frame that changes a bit. You can fly an H quad on + firmware, but it will be hard and it will look weird as the frame will fly at an angle.
There are small 40mm fans, which would be perfect. You would make a hole for the fan to mounted on one side of the plate, and an outlet hole on the other side - so the air runs over the ESC's before it exits the compartment.
Well since you already have 4 big fans on the vehicle, it seems weird to add another one. Maybe a bit of duct work would be useful.
Also holes at the bottom and top would vastly increase air circulation even without a fan. There is room for a few holes on top.
Re Fans for cooling. NEVER use an active power using solution on a battery powered device when a perfectly passable passive solution exist. IE for cooling on an aircraft use air scoops and/or ventilation holes in the structure.
Also using a separate switching BEC instead of the ESC BEC's for power will cause the ESC's to run MUCH cooler.