Low-turn motor with low gearing or high-turn motor with high gearing
08-08-2014, 12:32 PM
#1
Low-turn motor with low gearing or high-turn motor with high gearing
Hello,
I need some help figuring out what gearing and what turn motor I should buy for my future rc car and I was messing about on an R/C speed calculator website.
I used to think that the less turns a motor has, the faster it is and the less torque it has, but I am now confused.
The car I am going to buy is a Yokomo YRF001W which once built, should weigh somewhere between 1000~1300 grams. I am aiming for my cars top speed to be between 45-50 mph. This website doesn't ask for the weight of the vehicle so I wanted to know if anyone knows the pre-set weight setting on this website (It is the first website when you search "r/c speed calculator" on Google, web page has a carbon fibre background and a blue buggy logo).
With a 70t spur, a 41t pinion (48p), 21.5 brushless motor and a fully charged 2s lipo, It says I can reach 50.46 mph.
With a 70t spur, an 11t pinion (48p), 5.5 brushless motor and a fully charged 2s lipo, It says I can reach 50.46 mph.
With a 70t spur, a 26t pinion (48p), 13.5 brushless motor and a fully charged 2s lipo, it says I can reach 51.71 mph.
Which would be the best setup and what are the pro's and con's of each setup regarding temperature, run time, acceleration and torque?
I need some help figuring out what gearing and what turn motor I should buy for my future rc car and I was messing about on an R/C speed calculator website.
I used to think that the less turns a motor has, the faster it is and the less torque it has, but I am now confused.
The car I am going to buy is a Yokomo YRF001W which once built, should weigh somewhere between 1000~1300 grams. I am aiming for my cars top speed to be between 45-50 mph. This website doesn't ask for the weight of the vehicle so I wanted to know if anyone knows the pre-set weight setting on this website (It is the first website when you search "r/c speed calculator" on Google, web page has a carbon fibre background and a blue buggy logo).
With a 70t spur, a 41t pinion (48p), 21.5 brushless motor and a fully charged 2s lipo, It says I can reach 50.46 mph.
With a 70t spur, an 11t pinion (48p), 5.5 brushless motor and a fully charged 2s lipo, It says I can reach 50.46 mph.
With a 70t spur, a 26t pinion (48p), 13.5 brushless motor and a fully charged 2s lipo, it says I can reach 51.71 mph.
Which would be the best setup and what are the pro's and con's of each setup regarding temperature, run time, acceleration and torque?
08-08-2014, 02:11 PM
#2
The gearing calculator does not include any vehicle weight, aerodynamic load, etc. Mostly how fast the wheels will turn if held in the air, not so much of how fast the RC will actually go. Only a reference, use with caution.
All motor comments are based on the assumption that the motors are otherwise similar, can and rotor size, number of poles, general design, ran on the same battery voltage, etc:
The lower turn motor typically has only slightly less torque, and then mainly at lower RPMs. But it should also be geared lower, thus will deliver more torque at the wheels at all speeds. Will provide more acceleration and speed.
If all are geared correctly the lower turn motor will run hotter, and use up the battery quicker, to go faster. Note it is possible to make a higher turn motor run hotter with incorrect gearing, but that's hardly a fair or useful comparison.
Which is best is a difficult answer. Depends on how important each factor is, how the RC is being used, etc. Note it is very easy to overpower a RC these days. A standard 1/10 scale 540 size 5.5 turn on 2S is a tremendous amount of power and can be tricky to gear correctly to prevent overheating.
All motor comments are based on the assumption that the motors are otherwise similar, can and rotor size, number of poles, general design, ran on the same battery voltage, etc:
The lower turn motor typically has only slightly less torque, and then mainly at lower RPMs. But it should also be geared lower, thus will deliver more torque at the wheels at all speeds. Will provide more acceleration and speed.
If all are geared correctly the lower turn motor will run hotter, and use up the battery quicker, to go faster. Note it is possible to make a higher turn motor run hotter with incorrect gearing, but that's hardly a fair or useful comparison.
Which is best is a difficult answer. Depends on how important each factor is, how the RC is being used, etc. Note it is very easy to overpower a RC these days. A standard 1/10 scale 540 size 5.5 turn on 2S is a tremendous amount of power and can be tricky to gear correctly to prevent overheating.
08-08-2014, 02:22 PM
#3
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With adjusted gearing they gave you the same mph with both a 21.5 and a 5.5...hmmm In a real world application, that's not gonna happen. For all the reasons Dave laid out.
08-09-2014, 04:47 PM
#4
The gearing calculator does not include any vehicle weight, aerodynamic load, etc. Mostly how fast the wheels will turn if held in the air, not so much of how fast the RC will actually go. Only a reference, use with caution.
All motor comments are based on the assumption that the motors are otherwise similar, can and rotor size, number of poles, general design, ran on the same battery voltage, etc:
The lower turn motor typically has only slightly less torque, and then mainly at lower RPMs. But it should also be geared lower, thus will deliver more torque at the wheels at all speeds. Will provide more acceleration and speed.
If all are geared correctly the lower turn motor will run hotter, and use up the battery quicker, to go faster. Note it is possible to make a higher turn motor run hotter with incorrect gearing, but that's hardly a fair or useful comparison.
Which is best is a difficult answer. Depends on how important each factor is, how the RC is being used, etc. Note it is very easy to overpower a RC these days. A standard 1/10 scale 540 size 5.5 turn on 2S is a tremendous amount of power and can be tricky to gear correctly to prevent overheating.
All motor comments are based on the assumption that the motors are otherwise similar, can and rotor size, number of poles, general design, ran on the same battery voltage, etc:
The lower turn motor typically has only slightly less torque, and then mainly at lower RPMs. But it should also be geared lower, thus will deliver more torque at the wheels at all speeds. Will provide more acceleration and speed.
If all are geared correctly the lower turn motor will run hotter, and use up the battery quicker, to go faster. Note it is possible to make a higher turn motor run hotter with incorrect gearing, but that's hardly a fair or useful comparison.
Which is best is a difficult answer. Depends on how important each factor is, how the RC is being used, etc. Note it is very easy to overpower a RC these days. A standard 1/10 scale 540 size 5.5 turn on 2S is a tremendous amount of power and can be tricky to gear correctly to prevent overheating.
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