throttle set up with speed adjust-resistor--Question

I had a Lutzow once with that single motor/dual shaft gearbox in it. It worked well using a stock BC motor. Don't rule it out as an option.

 

You can use either two of the smaller gearboxes or one of the twin shaft/single motor gear boxes (with a 550 motor) to power your ship. Gearing down the shaft might seem like it is going to slow down the ship but if the motors are straining to move the ship then by reducing their load they will spin faster and your prop speed should turn out about the same. The difference would be that you don't trip up your ESC and you might see slightly better acceleration. Electric motors are not like gas motors, they behave differently and actually like to be run at higher rpm's with a light load.
When in series they are running at half speed because each one is getting only about half the voltage. Voltage determines motor rpm. Hook one of theose up to 12v and you will see what I mean. Lower voltage will not help your speed controler out though as it is too much current (amps) that is tripping up your esc.

 

thx for the info hovey. looking at getting a gear box. also, change the speed controler today to a viper 25 amp. did not run it full throttle, worked fine today. going to try again tommorrow also. but defintly, going to install gear box, just not sure if trwo singles or a double shaft with one engine.