I am planning to build a homemade ROV, and I wanted to know a couple of things about the motors. First is: Will it be Ok, if I use a brushed DC motor, instead of a brushless motor, and is there any major disadvantages ? Second : What RPM DC motor should I aim for ? High RPM or low RPM ? Will 600rpm be enough ? The specific motor that I am talking about is http://www.ebay.ca/itm/37mm-12V-DC-600RPM-Replacement-Torque-Gear-Box-Motor-New-/320984491847?hash=item4abc2aa747:m:mEBEQXXpqmNg4-vxmFaZP5w
Will this be a good motor for the propellers of the ROV. I am planning to have 4 motors / propellers. Two for upward and downward thrusting, and 2 for forward and side thrusting. The propellers that I plan to use, are basic plastic 3 blade propellers, with diameter, between 40mm and 50mm.
My main question is, what RPM and torque should I aim for when choosing the DC motor ?