Hi Everyone - I compete at the top level in Stihl Timbersports/Lumberjack Sports competitions. One of our events is the hot saw where we are using Rotax or Honda CR 250-350 cc motors for our power source. Here is a video
https://youtu.be/G9DiMPGsH9U?t=12037. We are typically racing through three cuts of white pine or other soft woods 16-20" in diameter. Top times are 5-7 seconds.
For a while now I've thought that going electric could be a game changer for a few reasons. There would be no warm-up or start issues, there should be less vibration making for smoother operation, and the motor would reach top speed faster. Maintenance and reliability should be easier/better as well. Stihl recently gave me their top of the line lithium ion saw, the MSA-220C, to test and it checks all the boxes above compared to a gas saw of the same size, albeit a tuned up gas aw of the same size would be still be faster.
The two potential cons I see could would be that the electric motor could have so much torque that it throws the chain when I hit the throttle, and the potential weight of the battery back. The weight issue could be mitigated by either a small battery pack (I'd be running saw for 7-12 seconds max per run) or a battery pack that stays stationary on the ground and connects to the saw via cables, thus the battery pack does not need to be lifted. I"ve heard that supercapacitors might be better than batteries as they can dump a lot of power quickly.
I'd like to know what types of electric motors and power packs I should be looking into for the build. Our saws are topping out at 55-60 hp at 9000-10000 rpm. I am unsure of the torque. Chain speed maxes out around 200mph or 290 feet per second. The typical saw weighs between 50 and 60 lbs. Anything larger can slow down the operators ability to move fast through the cut transitions.
The normal heat time for our races is 6-9 seconds depending on size and hardness of the wood. The max range for a very large and hard piece of wood would be 12-14 seconds.
I'd like to know what the electric motor experts think about the potential for an electric racing saw build. Will I be able to match or exceed max power and chain speed of our two stroke motors? If so, what motors should I look into? Would the increased torque be an issue for throwing or breaking the chain? How about power packs? What types of batteries or supercapacitors should I look into? Finally, what would be the weight and cost of the recommend motor and batter components be?
Thanks!
