Sarcassidy
1 µW
- Joined
- Feb 27, 2020
- Messages
- 3
Thank you all for the information. I'm taking it all in with great interest. My hot saw builder is now monitoring the thread as well and his ears are perked! I've done my best to answer some of your questions. Please keep the feedback coming.
Whether the saw will be accepted into competitions is unknown. Stihl Timbersports - the competition I care the most about - has three principal hot saw technical rules of consequence: only one person can carry saw onto stage and operate it, it is limited to one cylinder, and must have a "tuned" exhaust. The one person rule is a non issue. This saw will have no cylinders, so the "limited to one cylinder" rule shouldn't be a problem either. The "tuned exhaust"is the tricky one. I have two plausible arguments. The first is that the "tuned exhaust" rule isn't currently enforced as a few guys run a Wankel rotary engine with exhaust systems that are completely stock. The second is to challenge the definition of what "exhaust means". While this motor wouldn't be expelling waste gases, it would be moving air around in some way, correct. As long as I can point to one component on the build and say that it channels or directs air flow in some way I should be good. If desperate, I suppose I could go full jackass and just weld a pipe to the frame and claim it is a "tuned exhaust".
My intent would be to keep this build under wraps and only unveil once I carry it on stage to compete at the Stihl TImbersports US Championship. The judges would be forced to make a controversial decision to either allow the cut or disqualify me. I think this would be fun. I have a reputation for loophole mining the rules a bit. It helps that I'm the current champion as well. DQ'ing the champ for being innovative will be a tough call to make.
Finally, Stihl as a power equipment company is moving a large portion of their product line over to electric battery tech. They know that electrification is the future. From a corporate ethos standpoint they would be in a bit of a hypocritical position if they were to prohibit the sort of tech and innovation their R&D department is pursuing.
A few more technical and contextual details on the Honda 330 I'm currently running.
- Direct drive
- It weighs about 55 lbs. If I go to a carbon fiber frame I can cut it down to 48. The ICE motor and exhaust make up about 30 lbs. of that weight.
- Someone asked about kart motors being used. One guy uses one from hammer racing. It is very fast, but very finnicky. This guy races with a "2nd place is the first loser" mentality...win or go home!
- Fuel is typically VP or Sunoco 110. A few saws run on alcohol. Alcohol saws can run hotter, but are also more finicky and unreliable. Hot, humid days really mess with them.
- The majority of new builds use the Honda CR 250 as the base motor and then bore the cylinder out to 330-370cc. Guys have gone up to 400 and 500 ccs, but this extra power comes with extra problems that makes the unit unreliable. The extra vibration causes welds to break and chains can throw or break. Rotax's are still in play as are a few KTMs and Wankel rotary engines. There is a fast suzuki 270 in the mix as well.
- For Stihl Timbersports competitions we cut 47 cm white pine. In Europe and Australia they cut a hybrid poplar that is equally as soft. This would be considered a medium diameter wood for racing purposes. 250 cc motors can be competitive with 350 cc motors as they can achieve the same chain speeds and the 47 cm soft wood doesn't require the power that a bigger motor provides. In competitions where you cut 50-60 cm logs, the larger 330s-370s start to run away over the 250s. Years back there was a two cut race on 64 cm doug fir (harder than pine). 400 to 500 cc single cylinder saws would win this event.
- We get 15 cm within to make the three cuts, all of which must be complete. If we cut through the 15 cm line anywhere it results in a DQ. This happens a lot…probably in 25-30% of competitive runs.
- In regards to chain grinding, pretty much everything has been attempted to enhance the cutting efficiency of the 404 high tooth chain. While the best grinders might not have engineering degrees, these guys are shop monkeys who live and breathe chain grinding. When they're not doing up race chains, they're grinding chains for professional logging crews. They're adjusting the chain in up to 20 different areas, are measuring things down to thousands of an inch, and will go as far to meticulously polish the entire chain in order to reduce friction.
The two guys making the majority of new builds are pretty adament that the 404 high tooth chain's ability to cut and remove wood is the current greatest limiting factor for performance. When attempts are made to make the tooth cut more aggressive or take the rakers down, the stress on the tooth is too much and chains can break. A really bitey chain can "push" the saw and operator around as well. There is an .80 guage harvester chain that could potentially handle the stress, but it has a larger cutting kerf which makes it much more difficult to get three complete cuts in the 15 cm wood allotment. Approximately 35% of competition runs already result in a DQ or DNF. Most of those are incomplete disks, cutting the line, or a saw not starting or dying and then flooding.
The components of a good hot saw run are considered to be 1/3 the motor, 1/3 the chain grind, and 1/3 the operator. Since the fastest ICE motors are mostly maxxing out the cutting potential of a well ground chain, smooth operation is where select operators differentiate themselves from the pack.
A lighter saw makes good operation easier. Fast hands for fast starts and transitions do as well. The rest is just good muscle memory and having the awareness to lean on or let up on the saw based on how the chain and motor is reacting to the wood.
A final intangible in regards to performance is reliability of the machine. Guys who are on top of maintaining their saws and replacing components constantly have less mechanical issues. This is also why the Honda CRs are taking over. They seem to have less mechanical issues than the Rotax's or the Wankels.
Given that the chain technology is unlikely to change anytime soon, and it appears that electric motors could provide the same chain speed and power as our ICE motors, so I'm most curious to know how an electric motor saw could both be more reliable and be operated faster. Things like not having to "start" the saw and going strait to the throttle with my right hand instead of the pull chord are attractive. So are not having to ever worry about bad fuel or adjusting the jetting based on altitude, temperature, or humidity. With that here are my principal questions moving forward.
- Is there an e-motor configuration that will come in under 20 lbs.? 10 lbs. less weight than the ICE motors would be a big deal as far as handling goes. I’m not worried about the wieght of the batteries. The idea of having them in a backpack or remaining on the ground and connecting via cables sounds ideal.
- Will the vibration be less? Would there be any other potential handling problems? People mention "gyroscoping". I have an idea of what this is, however more explanation would be appreciated.
- How are these motors going to hold up? How often will components need to be replaced? I understand that it may be hard to give concrete answers until sufficient testing is done.
- Will there ever be start issues? Could something happen where when I go to hit the throttle and something isn't correctly configured?
- Will these e-motors run the same regardless of atmospheric conditions (temp, humidity, altitude)?
Safety is obviously a concern as well. Is electrocution an issue? How about batteries exploding, leaking, or becoming unstable? What happens to a motor when it gets pushed too far? If I mess up a motor, can it be fixed? What is "runaway" that people keep mentioning. Are there any other safety concerns that pertain specifically to an e-motor and the batteries?
Finally, I'm located in Minneapolis, MN. The guy that builds my saws is in Chico, CA.
Thanks again!
Whether the saw will be accepted into competitions is unknown. Stihl Timbersports - the competition I care the most about - has three principal hot saw technical rules of consequence: only one person can carry saw onto stage and operate it, it is limited to one cylinder, and must have a "tuned" exhaust. The one person rule is a non issue. This saw will have no cylinders, so the "limited to one cylinder" rule shouldn't be a problem either. The "tuned exhaust"is the tricky one. I have two plausible arguments. The first is that the "tuned exhaust" rule isn't currently enforced as a few guys run a Wankel rotary engine with exhaust systems that are completely stock. The second is to challenge the definition of what "exhaust means". While this motor wouldn't be expelling waste gases, it would be moving air around in some way, correct. As long as I can point to one component on the build and say that it channels or directs air flow in some way I should be good. If desperate, I suppose I could go full jackass and just weld a pipe to the frame and claim it is a "tuned exhaust".
My intent would be to keep this build under wraps and only unveil once I carry it on stage to compete at the Stihl TImbersports US Championship. The judges would be forced to make a controversial decision to either allow the cut or disqualify me. I think this would be fun. I have a reputation for loophole mining the rules a bit. It helps that I'm the current champion as well. DQ'ing the champ for being innovative will be a tough call to make.
Finally, Stihl as a power equipment company is moving a large portion of their product line over to electric battery tech. They know that electrification is the future. From a corporate ethos standpoint they would be in a bit of a hypocritical position if they were to prohibit the sort of tech and innovation their R&D department is pursuing.
A few more technical and contextual details on the Honda 330 I'm currently running.
- Direct drive
- It weighs about 55 lbs. If I go to a carbon fiber frame I can cut it down to 48. The ICE motor and exhaust make up about 30 lbs. of that weight.
- Someone asked about kart motors being used. One guy uses one from hammer racing. It is very fast, but very finnicky. This guy races with a "2nd place is the first loser" mentality...win or go home!
- Fuel is typically VP or Sunoco 110. A few saws run on alcohol. Alcohol saws can run hotter, but are also more finicky and unreliable. Hot, humid days really mess with them.
- The majority of new builds use the Honda CR 250 as the base motor and then bore the cylinder out to 330-370cc. Guys have gone up to 400 and 500 ccs, but this extra power comes with extra problems that makes the unit unreliable. The extra vibration causes welds to break and chains can throw or break. Rotax's are still in play as are a few KTMs and Wankel rotary engines. There is a fast suzuki 270 in the mix as well.
- For Stihl Timbersports competitions we cut 47 cm white pine. In Europe and Australia they cut a hybrid poplar that is equally as soft. This would be considered a medium diameter wood for racing purposes. 250 cc motors can be competitive with 350 cc motors as they can achieve the same chain speeds and the 47 cm soft wood doesn't require the power that a bigger motor provides. In competitions where you cut 50-60 cm logs, the larger 330s-370s start to run away over the 250s. Years back there was a two cut race on 64 cm doug fir (harder than pine). 400 to 500 cc single cylinder saws would win this event.
- We get 15 cm within to make the three cuts, all of which must be complete. If we cut through the 15 cm line anywhere it results in a DQ. This happens a lot…probably in 25-30% of competitive runs.
- In regards to chain grinding, pretty much everything has been attempted to enhance the cutting efficiency of the 404 high tooth chain. While the best grinders might not have engineering degrees, these guys are shop monkeys who live and breathe chain grinding. When they're not doing up race chains, they're grinding chains for professional logging crews. They're adjusting the chain in up to 20 different areas, are measuring things down to thousands of an inch, and will go as far to meticulously polish the entire chain in order to reduce friction.
The two guys making the majority of new builds are pretty adament that the 404 high tooth chain's ability to cut and remove wood is the current greatest limiting factor for performance. When attempts are made to make the tooth cut more aggressive or take the rakers down, the stress on the tooth is too much and chains can break. A really bitey chain can "push" the saw and operator around as well. There is an .80 guage harvester chain that could potentially handle the stress, but it has a larger cutting kerf which makes it much more difficult to get three complete cuts in the 15 cm wood allotment. Approximately 35% of competition runs already result in a DQ or DNF. Most of those are incomplete disks, cutting the line, or a saw not starting or dying and then flooding.
The components of a good hot saw run are considered to be 1/3 the motor, 1/3 the chain grind, and 1/3 the operator. Since the fastest ICE motors are mostly maxxing out the cutting potential of a well ground chain, smooth operation is where select operators differentiate themselves from the pack.
A lighter saw makes good operation easier. Fast hands for fast starts and transitions do as well. The rest is just good muscle memory and having the awareness to lean on or let up on the saw based on how the chain and motor is reacting to the wood.
A final intangible in regards to performance is reliability of the machine. Guys who are on top of maintaining their saws and replacing components constantly have less mechanical issues. This is also why the Honda CRs are taking over. They seem to have less mechanical issues than the Rotax's or the Wankels.
Given that the chain technology is unlikely to change anytime soon, and it appears that electric motors could provide the same chain speed and power as our ICE motors, so I'm most curious to know how an electric motor saw could both be more reliable and be operated faster. Things like not having to "start" the saw and going strait to the throttle with my right hand instead of the pull chord are attractive. So are not having to ever worry about bad fuel or adjusting the jetting based on altitude, temperature, or humidity. With that here are my principal questions moving forward.
- Is there an e-motor configuration that will come in under 20 lbs.? 10 lbs. less weight than the ICE motors would be a big deal as far as handling goes. I’m not worried about the wieght of the batteries. The idea of having them in a backpack or remaining on the ground and connecting via cables sounds ideal.
- Will the vibration be less? Would there be any other potential handling problems? People mention "gyroscoping". I have an idea of what this is, however more explanation would be appreciated.
- How are these motors going to hold up? How often will components need to be replaced? I understand that it may be hard to give concrete answers until sufficient testing is done.
- Will there ever be start issues? Could something happen where when I go to hit the throttle and something isn't correctly configured?
- Will these e-motors run the same regardless of atmospheric conditions (temp, humidity, altitude)?
Safety is obviously a concern as well. Is electrocution an issue? How about batteries exploding, leaking, or becoming unstable? What happens to a motor when it gets pushed too far? If I mess up a motor, can it be fixed? What is "runaway" that people keep mentioning. Are there any other safety concerns that pertain specifically to an e-motor and the batteries?
Finally, I'm located in Minneapolis, MN. The guy that builds my saws is in Chico, CA.
Thanks again!
