by chrisguyw » Mon Jul 08, 2019 3:18 pm
Hello to all..!!!.....A couple of things to consider when choosing the 25K BB Piranha motor for use/proxy use.
It is a very fine motor, its main benefit/advantage are its neo magnets, which as most have discovered, are considerably stronger than those found in the typical motors used to power the cars most of us run....(there have been similar "neo" magnet motors produced in the past,...the MBSlot "dodo" being the most widely used of the bunch.)
Keeping it simple,..the neos produce a significantly stronger magnetic field than ceramics/metal alloy, and this field results in more torque, and therefore braking, for a given armature wind/stack length. For those that run on plastic track, the significant downforce produced by these neos (via "can leak"/saturation), will result in a car that feels like it has a mild traction magnet. I have not measured the actual downforce that this motor will provide on a plastic track. but, I do have several MBSlot "dodos"(with similar magnets/can) and these consistently post 60+ grams of downforce on a magnet marshal. (The MBSlot "dodos" were discontinued 7/8 years ago, as many Euro clubs thought a "magnet" motor in a no magnet class was a bit of a cheek, considering the widespread use of plastic track overseas).
For wood track racing, some will like/appreciate the added torque (therefore braking as well), and, as neos are generally lighter than ceramic magnets, the motor is a tad lighter than some, which can have positive handling effects when installed due to a lower "moment of inertia".
So, while I do think the motor is quite nice, there are some things that you may want to consider for proxy events.
While quality ball bearings can/do offer some advantages, there are some things to keep in mind......quality bearings are not cheap, far from it, and it is more than generally accepted by virtually all commercial track/international racers that a sintered bronze bushing offers more benefits than any inexpensive ball bearing.....the less expensive ball bearings have less precision, and therefore, more slop than a sintered bushing........this can result in movement of the motor shaft, which negatively effects both gear mesh and handling.
Additionally, the bearings do not hold oil like the sintering in bronze, so....the bearings must be oiled much more frequently to avoid wear/seizing. If the proxy rules allow hosts to inspect/oil motor bearings, that is one thing,....if not, a sintered bronze bushing motor may well be more advisable.
I have nothing bad to say about this motor,....I do like it, but, I understand its potential limitations, and will use it in only specific circumstances.
Cheers
Chris Walker