ORIGINAL: speed-king
srry about that Ryan, im not trying to ignore you. I made a quick uneducated decision (before i saw your post about the motors) about the motor thinking that 12v would be faster than
the 8.4v. I gues not. if the 8.4v motor is better ill check it out. does that motor still runn on 12 cells?
In FE boats you will find over 95% of the hulls in here have water cooled motors. The 8.4v motor on 12 cells will run you very close to 30mph if not over. I would highly recommend water cooling the can and brushes. This is standard practice in FE boating.
The rated voltage on the motors are industrial ratings specifying the voltage in which provides the best life and performance. The lower this voltage rating is, the higher the KV. A lot of these motors are not made specific to R/C and used in several industrial applications.
I have ran several 700 8.4v motors on 12 up to 14 cells for years. They run a long time on this voltage. Key point is, it isn’t voltage that burns up motors, it is current. This is controlled solely by the prop or load placed on a motor.
Graupner 700 8.4v motor has a kv of 1750 and will spin up to a loaded 20 000RPM on 12 cells. This is a pretty common setup for LSH and LSO racing.
ORIGINAL: peterpella
When boat is running only falf of prop should work in the water. So, how to determine where to put the prop shaft when is not running, during assembly, to get such effect? I know how to do it, does Ryan too? Any theoretical opinions? Maybe some mathematics?
It’s not that difficult at all, many boats are setup so that the prop shaft exits the very bottom of the vee. This makes it very consistent from boat to boat no matter how heavy or large the prop is. A reference point must never be something that can vary with weight or prop size.
I found that if the prop shaft exits the boat a little higher such as 1/8” clearance for 22-30” mono’s from the bottom of the vee to the bottom of the prop shaft, much better handling and performance are expected.
I’m not to fond of the Graupner hulls. Weak performance and low quality hardware. A boat without water cooling is typically found in the scale section of RCU not in FE.
Ryan