PDA

View Full Version : Sports Cup: which motor to be hand-out?


doug01n
2015.05.21, 11:50 AM
Hi guys,

Mini-z Scene is growing up in Brazil... and we need an advice.

I was searching on this thread: http://mini-zracer.com/forums/showthread.php?t=40237&highlight=sports+motor and didn't came to a conclusion, so I ask you guys:

Which motor is a good one for hand-out championships with MR-03 Sports?

I ask this because we have a lot of new guys running Sports with us, and PN70T is not 100% compatible with it.
- Is limiting the gear ratio to 7/42 a 100% safe method? 8/42 maybe?
- Is there any other motor good for hand-out, once 80T is out of stock and will not return any time soon?
- Original motors that came with Sports version has the same difference between them, so when you put them on the track, there's some cars that have more top speed/torque than the others.

Objective is to establish a good motor for all the drivers can have a stock race in equal conditions, like PN70T cup. Options parts are not allowed at this moment, but in the future it will be.

Thank you.

briankstan
2015.05.21, 11:54 AM
from my experience all motors no mater the manufacture have some differences between the same type of motor.

if you are worried about them being compatible than I would simple stick with the Kyosho stock motors, although I'm not sure about getting quantities for using them as a hand out for and event.

doug01n
2015.05.21, 12:19 PM
I agree with all having some differences, but we are running 70T motors for a long time, and tolerance shown so far is arround 5%. We have found 20% difference between Stock motors of Sports versions. Besides the fact that we don't know how to get so many motors for hand out as your concern.

arch2b
2015.05.22, 05:02 AM
Getting stock motors in that quantity is going to be marginally different in cost to 70t. Unless you series is on a small track I would stick with 70t. It's not easy finding large quantity of stock motors unless you run across someone who has a box of them unused.

Mike Keely
2015.05.22, 07:07 AM
Try here

http://www.robotshop.com/en/brushed-dc-motor-6v-11500rpm.html

I should add in here that I am not sure if this is a perfect fit. Check the measurements.


They have a few motors that are 3-12 volt. Most are under $2 plus shipping so you may want to get a few extra.

Mike Keely
2015.05.22, 07:12 AM
In most cases you are going to find the type of battery used will vary the speed of the cars more then a variation in the motors. If everyone uses the same milli-amp rating batteries the cars will be very close.

Mike Keely
2015.05.22, 07:16 AM
I agree with all having some differences, but we are running 70T motors for a long time, and tolerance shown so far is arround 5%. We have found 20% difference between Stock motors of Sports versions. Besides the fact that we don't know how to get so many motors for hand out as your concern.

How are you checking the motors?

Jshwaa
2015.05.22, 03:07 PM
How are you checking the motors?

How do they qualify a motor as being 'stock'? Are they all purchased 70t motors direct from Kyosho?

DMALMAD
2015.05.23, 08:12 AM
70t or 50t pn motors are used as stock and super stock motors. Usually handout motors if there is a big race but otherwise just 70t or 50t from PN. 70t seems to be the most popular but for LM and F1 and some tracks 50t is good too for stock racing.

Jshwaa
2015.05.23, 10:17 AM
70t or 50t pn motors are used as stock and super stock motors. Usually handout motors if there is a big race but otherwise just 70t or 50t from PN. 70t seems to be the most popular but for LM and F1 and some tracks 50t is good too for stock racing.

I see. Guess that puts the emphasis on cells...

Are you allowed to do anything to the motor before the race(ie. wear-in, commutator drops, lubrication, etc.)?

mleemor60
2015.05.23, 11:11 AM
I think the more appropriate word would be "spec" instead of "stock". The PN 70T has become the accepted standard for RCP while the PN50T is a marginally better choice for carpet since the added drag from the surface places more emphasis on the lower turn motor to maintain what most drivers feel is parity in performance.

DMALMAD
2015.05.23, 01:27 PM
I see. Guess that puts the emphasis on cells...

Are you allowed to do anything to the motor before the race(ie. wear-in, commutator drops, lubrication, etc.)?
If it is a handout motor you are allowed to do anything whithout taking the brushes or plastic cap part off. If it is just a 70t class you should be able to replace the brushes. I know some used to use comm drops, especially with handout motors but that would always lead to the fast motor the week before becoming a dud. Personally I try and always break them in when they are new in water or wd and then clean the comm up a bit with a comm stick.

arch2b
2015.05.23, 10:26 PM
thats a liberal sense of 'stock' :p

it really depends on the interpretation of stock. as you see, some feel a 50t is 'super stock' while other will tell you 50t is mod. the common standard for stock is the box stock motor or the 80t equivalent that kyosho released. as both are not readily available or cost effective compared to similar motors from pn/atomic, most simply accept the 70t as it's the closest of the bunch, much easier to obtain and not expensive. if you could find the box stock or 80t easily as the 70 at less cost, i'm sure this conversation would be slanted differently. the basis of decision for most is really a factor of availability and cost. the atomic standard bb motor was a fantastic motor when it was mass produced and widely available. maybe not as durable as the pn 70t but it was well liked.

doug01n
2015.05.25, 04:45 PM
Thank you guys for all the opinions.

We are measuring with tamyia speedchecker, and also tried with some geek measuring using a home made laser reflection rev meter. Speed on standard mount with 9/42 using solid axle was from 24 to 32 with 6.0V DC in original motors.

We tried out 70T limiting gear ratio to 8/42, and there were no burned fets. So we are thinking about using 70T motors with this limitation of gear ration, and leave it open for ASF race. I also have spoken with Philipe, and he confirmed that using 8/42 ratio will prevent to have any kind of burned fets, even from first batch of sports, if any here in Brazil.

About comm drops, we are still thinking about allowing. I think we may choose one kind of comm drop and authorize the use.

lfisminiz
2015.05.25, 06:17 PM
Sounds like you guys are going in the right direction...sounds good.