graupner 700 bb turbo

[gasfreak]

Does anybody know if a 700 bb 8.4 or a 700 9.6 will handle 16 cells and which would be the fastest in a key west cat,and will the boat handle this

 

[Pennywizz6]

It will not handle 16 cells, 16 cells is roughly 19.v, thats more than twice it is rated for. It does depend on the load though, but more or less it will eat brushes like crazy. During the time it would run it would go fast, because the rpm curve would be much higher. Brushless will always have the top spot, I suggest a hacker c50. Although you will have to have deep pockets.

Phil B)

 

[Ed]

14 cells max with a good speed control from Astro Flight.

 

[jayt]

It will not handle 16 cells, 16 cells is roughly 19.v, thats more than twice it is rated for. It does depend on the load though, but more or less it will eat brushes like crazy.

The 700s have very hard brushes - the comm will burn before the brushes go bad. You can't replace the brushes nor turn the comm - not without tearing the sealed-motor down. The 700 is routinely used with 12 cells, and even with top-grade 3300s will last a lot of 10-lap heats. Plenty of racers run 14 to 16 cells, and the motor life is shortened; for occasional sport use it won't matter. Heat is the enemy, so with more than 12 cells, limit your run time to no more than 2 minutes, or watercooling is a good idea. You can safely run 14 to 16 cells if you use the less expensive 'sport packs', they don't deliver the power that good (and expensive) 3300s do. THe best brushless controllers are from rc-hydros.com, they are far better than AstroFlight.
But the Key West is not the best platform for 16 cells and a heavy 700 motor. It will run, but the weight is a lot for that small hull; you'll have to pray that you never breach the hull because it will sink like a rock - there is no point in even putting in floatation. I've run Keys for over a decade, and IMO 8 cells and an Astro 05 motor will get all the speed the hull will handle. Past around 35 mph the cat will not stay on the water well. With brushless power, 6 cells and the right mtor will make the Key fly. But for an economical setup, a good 600 series can motor and 8 cells will be more satisfactory IMO.