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This is based on relative can size. The Speed Calc also gives you a figure of merit in the motor speed calc area...
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Can size will give more torque but the kv matters too. A lower kv will give you more torque if the rotor size is the same.
Prime example would be the Proboat motors. Not sure they still make the 1500 but the can and rotor are the same as the 2000. They're just wound different. Both are great motors. Especially for the price but the 1500 has more torque and will turn a much larger prop at less total rpm. The beauty of that is/can be that you put a larger propeller blade in the water. A larger blade doesn't slip as much. Meaning it's more efficient. Acceleration is for sure better. Think digging a hole with a hand garden shovel or using a big spade shovel. Volume per scoop is higher with the spade. More efficient.
A big fat prop isn't always the answer though. My kids PT Stealth for instance doesn't like big props. We tried to get the 1500 to work but it just never liked the big blades. I know guys that have made it work on a Stealth. Every boat has it's own personality IMO. Ty's boat likes a small prop and the extra rpm we can get out of a 2000kv motor. We get a nice top speed this way but some of our guys pull harder out of the turn with a 1500. It takes them less time to get to full speed. Big scoops.
The interesting thing is that we GPS'd a 1500kv boat and a 2000kv boat. Both sport hydro oval racers with different mah batteries, different motors, and different props with the exact same top speed. Within a 10th of a mph. The difference (we think) is that the boat with the larger prop gets to that top speed a tiny tic quicker. Doesn't always translate to wins. You still have to put it in the right spot to win but all things being equal.
Craig once mentioned that watts are watts. Wasn't this thread but still true. Comes down to how many of those watts can you translate into thrust. My experience is that if you try to simply throw a 65000rpm (yes I have) into the water what you get is thrust with a LOT of wasted energy. You get many gallons of water thrown into the air. More friction from the entire drive line. More wear on every component. More resonance from anything that is less than perfectly balanced. A drive dog that hasn't been ground just right will eat your strut for instance. Immediately? Of course not. But it's coming.
This isn't a dig but typically guys that don't race are hesitant to spend big dollars on motors and such. Why the heck would ya? A Lehner motor will have killer bearings. Just shy of ceramic. Priced accordingly. It will absolutely handle most of the rpm you can dream up. A Leopard or even a TP? Hmmmm Sketchy. Good motors but not like a Lehner or a Neu. So we take a new......er guy and turn him loose with a high rpm setup that really needs to have every rotating piece balanced to keep it safe and hook it to a budget motor with a budget ESC and likely some budget batteries that produce crazy ripple currents. Go have fun buddy! Steven (OSE) has to be losing his mind trying to keep up with guys breaking things. To make it worse for him, guys are buying stuff because they read on here that it was a good setup. They want it replaced because "it worked for some guy on the internet". The fact that there was no gap in the strut and the amperage went from sane to explosive is omitted from the conversation. "It just burned up". Where does that leave OSE? Replace everything isn't going to keep him in business. Don't replace stuff and he's the bad guy. Gotta be a nightmare at times.Noisy personComment
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2200 on 6s all day long?? Maybe for a few zip-zip passes, not a reliable sport setup. Its like when someone refers to a setup they saw someone running in a youtube video...must be reliable since someone has a 1 minute video of it right!?Comment
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Yep, it's a strange world... most just don't want to "bother" with all the details, like a Vegas wedding! It's just like business, you need to know your business to be successful. You can't pay someone to know your business!
But this sport should have people with a natural curiosity to how things work... it's the curiosity that produces the drive to dig in and learn, the "how comes" and "why nots" produce a tendency to ask questions and learn. The Interwebs have proven to be a great thing and a horrible thing. It's great that so much info is there, it's horrible when people feel that others have "done their business" for them.
Setups that are offered here are NOT intended to be your destination folks! It's intended to be your starting point. To get you off safely, so you still have a boat around after Day 1 to learn with. So respect the sport and keep on the journey of self discovery, which is really where the fun is!Comment
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This is a big point... There are different goal sets for different people. This is what makes this hobby great! I'm the opposite, just blasting straight doesnt butter my bread.. For me, the beauty of seeing a hydro go through the different ride changes from straight to cornering is exciting for me. Through all of that, there are distinct differences in the needs and demands of the electrical system. What works well for circle runners probably isn't going to be effective for SAW. But I don't think we need to express opinions if one is "better" than the other, that is just divisive. I don't think and I didn't take Prodriver's comments negatively at all. Let's all just enjoy the hobby the way that gives us the most pleasure!Comment
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Saw passes bore me to tears. A single boat all by itself with nobody around to laugh and have some fun with.........................................sorry I dozed off.....................what was I typing about?.......................
Oh yeah....roundy rounds. Put some buoy and 4 more guys on the pond. A five boat heat involves 5 racers, 5 pit guys (these are spotters), and at least one guy calling the heat. So 11 morons that love RC boats all laughing and acting a fool. Swap leads a couple times. Set a guy up so he makes a mistake and you can dip under him to thieve the lead in the last turn. Finger pointing at the end of the heat. Talk crap about that pass.
"Where did you get the extra speed coming out of 4?"
"I'll show ya"
I can't even put a price on that fun factor. Even my wife has quit trying to.
Don't get me wrong. I still go to the time trials. Going this weekend. I've got a nasty Q mono Wildthing to run through the lights. Truth is, I get more joy out of BS'n in the pits than I do running at those events. Helps to know everyone there but if ya go and stay for more than an hour you'll likely know everyone there too. It's just how racers are wired. Excuse the pun.Noisy personComment
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But the point is, there's no more value in your enjoyment going roundy round then to an individual that SAW puts wood on. Myself, I'm not blessed with living in or near a location frequented by 11 other like minded hobbyists on a given outing, so I just make noise, scare off the water fowl, and try to keep my boats off the rocks.Vac-U-Tug Jr (13mph)Comment
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Try being from Toronto, Canada! The only thing I can race around here is a sailboat with a servo! I envy you guys......
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Ryan
We will have about 40 guys out this Sat. the 30th.
Come and join in on the fun.
Wellesley Apple Butter & Cheese Festival
Wellesley Ontario, Sat. get their by 8:00 AM for parking at the pond.
LarryPast NAMBA- P Mono -1 Mile Race Record holder
Past NAMBA- P Sport -1 Mile Race Record holder
Bump & Grind Racing Props -We Like Em Smooth & WetComment
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Folks frown upon electric boats up there? When I lived in California in the 80's and 90's, people would give me a hard time when I ran my nitro boat. Put oil in the pond and scared the birds... In Oklahoma, people come out with their kids to see the boats run. I've got all FE now, no nitro or gas. Too noisy and they can leave oil in the water...Comment
Do you guys meet there often? I would certainly like to check it out sometime!
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