Running 2 brushless motors off one ESC has been done successfully, but with great care. Identical motors, identical wiring, identical loading, great care taken to ensure that the ESC chosen could handle the power of two motors. The idea can only work with unsensored motors, as sensors would only create confusion.

Much simpler to use one ESC per motor on a Y lead. Has the advantage that you get to put the (smaller) ESCs where you want them, rather than planting one larger one where it decides.

Could be cheaper fit one prop (if practical) one brushless one escape I changed to one brushless one prop to replace 3 and 3 MFA 850's

What brushed motors do you have fitted? And do you know what current they take?

A wattmeter is a handy device as it shows not only the power being consumed/developed, but can be used as gauge for how much the motors are being loaded.

28mm outrunners are an adequate replacement for anything up to a speed 600, and they come in various Kv and wattages, so this would have a bearing on what esc you need.

Ashley

Hi Chris, like Ashley says, the old motors are probably some type of 540 ones. Over the last couple of years I've replaced 4 of these in my models with brushless motors. My lightweight crash tender/ fire float has a 28mm outrunner, as has my rtll. Both are faster and run longer with no heating, water cooling would be silly in models like these that are running well within the motors limits. I've also a large heavy Garr Wood Speedster, with a 35 mm outrunner that runs fast and cool.

The point is that I would recommend outrunners for normal models, no cooling needed. I just chose a kv rating to match the battery voltage in each model, it's that simple.

Charles.