- Joined
- Apr 27, 2007
- Messages
- 3,510
Lohring,
Joerg and I have this discussion over dinner about once a month with my frequent trips to Germany for work. We are trying to solve two different problems. In the racing Joerg is trying to target that have a timed race with a mAh limit and/or weight limit on their cells. Guys are running batteries down destroying the cells in the process. Joerg has proposed a mAh counter that each boat would have and would be checked after a race. This would allow racers to run larger capacity cells and not kill a pack every run. It's a good concept that will need development, but also has some flaws. How do you check for tampering, how accurate is a shunt or hall current measurement device to guarantee equal mAh usage? Do you make everyone buy these devices or are they swapped throughout the day and owned by the organization? Is it like a spec motor class where motors are handed out prior to the race? Does everyone have to run a standard connector and cable length? Who is responsible for calibration?
A kv checker has its own problems. You need to tap into the battery leads to get an accurate voltage for kv measurement. You need to clip onto one of the motors wires. You need to ensure the radio is outputting WOT. You need to ensure that ESC has a reasonable timing advance. You need to ensure the ESC does not have a RPM limiter. Joerg was nice enough to send me one and after trying to cheat it I found a number of ways to read lower kv. Kv is a not a good metric to try and tech.
Strictly for limited classes I liked the tech method of length and diameter. It's fairly easy to do in the hull and it only takes an inexpensive caliper to measure. Measuring the weight of the motor after the event would prevent guys like me from building copper intensive motors although it is a pain to pull some motors from boats where installation is tight. It would also require a scale to be brought to events. We would also have to clearly say what is considered part of the motor. Such as the connectors, cooling jacket, etc. If you have ever seen the FAI pylon racing motors than you know what I am talking about. If these were to be incorporated into the rules, I would suggest the top three places get teched after the race for motor weight like tear downs for OPC or stock Zenoah classes. There would be an opportunity to swap a legal motor in for the last heat, but this could be stopped by doing a quick tech at the beginning of the day for length and diameter and adding a sharpie mark, zip tie, sticker or some other method of identifying the motor.
I have only been to one race (outside of TT's) where battery voltage was measured prior to a run. Guys had to leave boats untaped in the hot pits, wait to be teched and could then tape up. This worked well although it was tough on guys with back to back races. This additional tech occurred as HV cells were just introduced and racers were concerned particularly for the limited class that racers using HV cells would have an advantage.
For the record I am not in favor of limiting any of the N, P, Q, S and T classes. I am in favor of finding a simple, easy to tech method applied to "limited" classes. My simple proposal would be a length and diameter limit checked at beginning of the first race and a weight check of the top three finishers at the end of the day. Battery cell count and chemistry limits would still apply. No current limiters, no mAh counters, propeller diameter or pitch limits.
-Tyler
Joerg and I have this discussion over dinner about once a month with my frequent trips to Germany for work. We are trying to solve two different problems. In the racing Joerg is trying to target that have a timed race with a mAh limit and/or weight limit on their cells. Guys are running batteries down destroying the cells in the process. Joerg has proposed a mAh counter that each boat would have and would be checked after a race. This would allow racers to run larger capacity cells and not kill a pack every run. It's a good concept that will need development, but also has some flaws. How do you check for tampering, how accurate is a shunt or hall current measurement device to guarantee equal mAh usage? Do you make everyone buy these devices or are they swapped throughout the day and owned by the organization? Is it like a spec motor class where motors are handed out prior to the race? Does everyone have to run a standard connector and cable length? Who is responsible for calibration?
A kv checker has its own problems. You need to tap into the battery leads to get an accurate voltage for kv measurement. You need to clip onto one of the motors wires. You need to ensure the radio is outputting WOT. You need to ensure that ESC has a reasonable timing advance. You need to ensure the ESC does not have a RPM limiter. Joerg was nice enough to send me one and after trying to cheat it I found a number of ways to read lower kv. Kv is a not a good metric to try and tech.
Strictly for limited classes I liked the tech method of length and diameter. It's fairly easy to do in the hull and it only takes an inexpensive caliper to measure. Measuring the weight of the motor after the event would prevent guys like me from building copper intensive motors although it is a pain to pull some motors from boats where installation is tight. It would also require a scale to be brought to events. We would also have to clearly say what is considered part of the motor. Such as the connectors, cooling jacket, etc. If you have ever seen the FAI pylon racing motors than you know what I am talking about. If these were to be incorporated into the rules, I would suggest the top three places get teched after the race for motor weight like tear downs for OPC or stock Zenoah classes. There would be an opportunity to swap a legal motor in for the last heat, but this could be stopped by doing a quick tech at the beginning of the day for length and diameter and adding a sharpie mark, zip tie, sticker or some other method of identifying the motor.
I have only been to one race (outside of TT's) where battery voltage was measured prior to a run. Guys had to leave boats untaped in the hot pits, wait to be teched and could then tape up. This worked well although it was tough on guys with back to back races. This additional tech occurred as HV cells were just introduced and racers were concerned particularly for the limited class that racers using HV cells would have an advantage.
For the record I am not in favor of limiting any of the N, P, Q, S and T classes. I am in favor of finding a simple, easy to tech method applied to "limited" classes. My simple proposal would be a length and diameter limit checked at beginning of the first race and a weight check of the top three finishers at the end of the day. Battery cell count and chemistry limits would still apply. No current limiters, no mAh counters, propeller diameter or pitch limits.
-Tyler
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