flying by the seat of my pants!
05-17-2007, 09:38 AM
#26
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RE: flying by the seat of my pants!
Hi Leigh,
Congratulations on your first build!
She's a beauty!
As for a motor, a five pole 300 series would be enough, a 400 series (again five pole armature, for smooth response) would get it on the plane, the car motor (20T) will almost certainly flip it due to torque issues...
This is on 7,2-8,4V ; as your space is restricted and hopefully the ESC you ordered has BEC, you should be able to run the entire boat on five penlights (preferable rechargeable) or four 'normal' penlights, the torque will hardly be a point.
To get a reasonable runtime, a fivepole 300 or 400 series would be the best option.
If the ESC plays along you could also try Lipo (2S), more power less weight.
Regards, Jan.
Congratulations on your first build!
She's a beauty!
As for a motor, a five pole 300 series would be enough, a 400 series (again five pole armature, for smooth response) would get it on the plane, the car motor (20T) will almost certainly flip it due to torque issues...
This is on 7,2-8,4V ; as your space is restricted and hopefully the ESC you ordered has BEC, you should be able to run the entire boat on five penlights (preferable rechargeable) or four 'normal' penlights, the torque will hardly be a point.
To get a reasonable runtime, a fivepole 300 or 400 series would be the best option.
If the ESC plays along you could also try Lipo (2S), more power less weight.
Regards, Jan.
05-17-2007, 01:35 PM
#27
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RE: flying by the seat of my pants!
Leigh,
Running any motor at less than full throttle is wasteful and produces heat somewhere. That does not mean that you can't use a large motor! Just expect some evidence of 'waste' showing up. As long as that 'waste' isn't too excessive, big deal. Instead of 'wasteful' you can substitute 'inefficient'. Same things apply. If it works like you want it to, and doesn't burn to the water line, then it's doing great.
- 'Doc
Running any motor at less than full throttle is wasteful and produces heat somewhere. That does not mean that you can't use a large motor! Just expect some evidence of 'waste' showing up. As long as that 'waste' isn't too excessive, big deal. Instead of 'wasteful' you can substitute 'inefficient'. Same things apply. If it works like you want it to, and doesn't burn to the water line, then it's doing great.
- 'Doc
05-18-2007, 07:47 AM
#28
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RE: flying by the seat of my pants!
heat never even crossed my mind. just how hot do the motors get? will alot of the heat be transfered through the hull into the water? or do i need to vent my boat in some sort of fashion to remove heat?
i'm still waiting on my speed control.
i also seem to have a new addiction. leds.
i had 1 small red led left from the zip zap i gutted. (it stopped holding its charge along time back) i actually purchased 10 zips last year from liquidation world at $4 canadian each. (probably cheaper than buying the leds themselves.lol)
i came up with a use for the last of the 4 leds.
can you say "scooby,dooby doo"? lol
i'm still waiting on my speed control.
i also seem to have a new addiction. leds.
i had 1 small red led left from the zip zap i gutted. (it stopped holding its charge along time back) i actually purchased 10 zips last year from liquidation world at $4 canadian each. (probably cheaper than buying the leds themselves.lol)i came up with a use for the last of the 4 leds.
can you say "scooby,dooby doo"? lol
05-18-2007, 12:26 PM
#29
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RE: flying by the seat of my pants!
Leigh,
Off hand, I doubt if heat is going to be a big problem for you. Run the thing for a bit then check it to see how hot it is. The 'standard' for determining 'too hot' is that you can't comfortably hold onto the motor (or battery, or ESC). If it start 'approaching' that 'too hot' point, it's probably time to start thinking about why, and then doing something about it.
A boat's hull seldom transfers enough heat to act as a heatsink. Wood and plastic are terrible heat conductors. Metal is a pretty good one, but then it depends on exactly which metal, where it is, how much of it there is, it's shape, and so on and so forth. You don't see many model boat hulls made from metal anyway. So, boat hulls just aren't used to transfer heat very much. 'Heat' is the most common 'by-product' of electrical stuff. Usually means something is working very hard. I didn't mean for you to worry about it, just something to keep in mind.
- 'Doc
Off hand, I doubt if heat is going to be a big problem for you. Run the thing for a bit then check it to see how hot it is. The 'standard' for determining 'too hot' is that you can't comfortably hold onto the motor (or battery, or ESC). If it start 'approaching' that 'too hot' point, it's probably time to start thinking about why, and then doing something about it.
A boat's hull seldom transfers enough heat to act as a heatsink. Wood and plastic are terrible heat conductors. Metal is a pretty good one, but then it depends on exactly which metal, where it is, how much of it there is, it's shape, and so on and so forth. You don't see many model boat hulls made from metal anyway. So, boat hulls just aren't used to transfer heat very much. 'Heat' is the most common 'by-product' of electrical stuff. Usually means something is working very hard. I didn't mean for you to worry about it, just something to keep in mind.
- 'Doc
