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Author Topic: Electric CL racing  (Read 5569 times)

Offline don Burke

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Electric CL racing
« on: November 05, 2016, 12:48:40 PM »
I was intrigued by the FF article in the last MODEL AVIATION.  They are using "joule timers" to limit engine runs.  Has anyone thought about using similar things in a CL racer sort of like limiting fuel tank size?  I have no idea of what engine size equivalents, but I do think one of the FF planes was an FAI type with a .15.
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don Burke AMA 843
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Offline Mike Callas

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Re: Electric CL racing
« Reply #1 on: November 05, 2016, 06:19:11 PM »
Don,
I flew F1Q for a year. The joule timers are not cheap so I used the alternate method of measuring the average motor watts and then using the FAI formula to calculate motor run time.
The esc can be set to a desired RPM to keep it even. It can be checked before and after the race with a fresh battery. The batteries need to be sized to allow a run that ends with no less than 20% battery capacity remaining.
Pitting would consist of replacing the battery and then pushing a button to go again.
More racing, no flipping theatrics.

I would guess a 3S battery- 11.1V and a ~2000kv motor might be a starting point. Pick a prop and RPM that everyone uses.

The motors are pretty cheap, ~ $30. The ESC is ~$50 and a timer from Hubin is $10. Batteries are $20 to $40 depending on size and brand.

Safety issue is lipo fire so a water jug/pail would be necessary.

When are we going to see you flying again?

Mike
« Last Edit: November 06, 2016, 12:26:30 AM by Mike Callas »
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Offline don Burke

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Re: Electric CL racing
« Reply #2 on: November 06, 2016, 07:13:07 AM »
Thanks, answers my questions.  Now all I need is the ambition to do something about it.

Don't know when I'll be flying again.
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don Burke AMA 843
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Offline Motorman

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Re: Electric CL racing
« Reply #3 on: November 06, 2016, 02:39:20 PM »
So with spec rpm and prop and no engine starting skills where is the race, who can change a battery the fastest?
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Offline Mark Scarborough

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Re: Electric CL racing
« Reply #4 on: November 06, 2016, 03:26:02 PM »
Quote from: Motorman on November 06, 2016, 02:39:20 PM
So with spec rpm and prop and no engine starting skills where is the race, who can change a battery the fastest?
Thats the problem in a nutshell, that and how do you insure that in the heat of battle that the battery gets secured. I see that being a issue.probably the biggest single issue with electric racing.
so it would come down to airframe construction and design, how you treat your batteries, and how smooth you fly
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Offline BillLee

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Re: Electric CL racing
« Reply #5 on: November 06, 2016, 03:54:24 PM »
Quote from: Mark Scarborough on November 06, 2016, 03:26:02 PM
Thats the problem in a nutshell, that and how do you insure that in the heat of battle that the battery gets secured. I see that being a issue.probably the biggest single issue with electric racing.
so it would come down to airframe construction and design, how you treat your batteries, and how smooth you fly

And that isn't racing!  HB~>
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Offline Brad LaPointe

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Re: Electric CL racing
« Reply #6 on: November 06, 2016, 04:17:39 PM »
Perhaps we require the pit man to charge the battery with a crank generator for pit stops.

Brad
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Offline Paul Smith

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Re: Electric CL racing
« Reply #7 on: November 06, 2016, 05:00:35 PM »
Righto.

Maybe the electric racing advocate could get six other guys to build one and show us how good it is.
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Paul Smith

Offline don Burke

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Re: Electric CL racing
« Reply #8 on: November 06, 2016, 07:24:55 PM »
Quote from: Paul Smith on November 06, 2016, 05:00:35 PM
Righto.

Maybe the electric racing advocate could get six other guys to build one and show us how good it is.
I was only looking at the possibilities.  As for things that do need to be considered one is definitely battery security.  I see a requirement necessary for quick change batteries be mounted/accessed from the inboard side of the fuselage only to try to prevent the obvious peril of batteries coming off in flight.

Also I feel there are some areas in the country that prohibit CL flying due to the noise of IC engines.
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don Burke AMA 843
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Offline Paul Smith

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Re: Electric CL racing
« Reply #9 on: November 06, 2016, 08:20:47 PM »
You could just learn to race RC drones.  No need to reinvent the quad-copter.
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Paul Smith

Offline Tim Wescott

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Re: Electric CL racing
« Reply #10 on: November 06, 2016, 08:53:36 PM »
Particularly for an 'experimental' event I wouldn't try to second-guess things very much.  Rather than fixing motor, prop, etc., just dictate line lengths and a maximum battery weight (I suggest 1.5 or 2 ounces for a "15-sized" race), and that at least one battery change and restart per race must be done.  Let people mess around with cell counts, props, motors, airframes, etc., to their hearts content.  Since ejected batteries are a concern, maybe make a rule that they have to mount from inboard, and make any sort of a "dangling battery" grounds for getting no score for that heat.

Then stand back and find out what solutions people find.  I don't think things will get too wacky, but if someone shows up with a 200mph racer that needs five pit stops per heat you can always impose a speed limit, or put a maximum on battery changes.
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Paul Smith

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Re: Electric CL racing
« Reply #11 on: November 07, 2016, 11:21:10 AM »
That or just fly one of the fifteen current racing events.
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Paul Smith

Offline Mark Scarborough

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Re: Electric CL racing
« Reply #12 on: November 07, 2016, 11:55:34 AM »
Quote from: Tim Wescott on November 06, 2016, 08:53:36 PM


Then stand back and find out what solutions people find.  I don't think things will get too wacky, but if someone shows up with a 200mph racer that needs five pit stops per heat you can always impose a speed limit, or put a maximum on battery changes.

good advice,, stand WAY WAY back, those batteries fly a long ways, dont ask me how I know,,
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Offline Motorman

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Re: Electric CL racing
« Reply #13 on: December 08, 2016, 03:26:19 PM »
Quote from: Tim Wescott on November 06, 2016, 08:53:36 PM
Then stand back and find out what solutions people find. 

Then make rules against them.

MM
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Offline john e. holliday

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Re: Electric CL racing
« Reply #14 on: December 09, 2016, 11:39:07 AM »
Quote from: Motorman on November 06, 2016, 02:39:20 PM
So with spec rpm and prop and no engine starting skills where is the race, who can change a battery the fastest?

Who can lead the plane fastest(whipping).
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Offline pmackenzie

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Re: Electric CL racing
« Reply #15 on: December 10, 2016, 05:57:21 AM »
Quote from: john e. holliday on December 09, 2016, 11:39:07 AM
Who can lead the plane fastest(whipping).

Even that could be reduced if you were required to run an EC that limited the max RPM. There is a pylon class called E2K where they developed custom ESC firmware to do that.

https://www.rcgroups.com/forums/showthread.php?2295862-Custom-ESC-firmware-with-fixed-max-RPM-for-pylon-racing&highlight=E2K

Makes a lot more sense for R/C pylon racing than it does for control line.
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