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Old Jul 01, 2002, 02:22 PM
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Ithaca NY
Joined Mar 2002
73 Posts
Formulas?

Hey,

I'm putting together a little form-based windows calculator to make easy use of common/useful formulas.

So, post your common/useful formulas here and I'll put it in (i'll give you credit if you wish, of course).

It'll mainly focus on e-flight, but similar to ezone, it'll also contain useful stuff on other areas of model flight.

Thanks
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Old Jul 01, 2002, 02:29 PM
Hmm, kerosene... :)
NightSwan's Avatar
Weert(LB) - the Netherlands
Joined May 2002
953 Posts
Don't have the formula handy at the moment, but something to
calculate the CG would be nice...

here's a link :
http://www.palosrc.com/instructors/cg.htm


And maybe the standard Power/Current/Voltage/Resistance thingie? (fill in two of the above, and calculate the other two or something similar) It's just ohms law, but hey, I'm lazy

Hans
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Old Jul 01, 2002, 02:31 PM
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Ithaca NY
Joined Mar 2002
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oh, V=IR is in there, dont you worry (im lazy too)
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Old Jul 01, 2002, 10:16 PM
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Ithaca NY
Joined Mar 2002
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CG formulas will also be going in there.

As well as a basic design param calculator.
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Old Jul 01, 2002, 10:33 PM
Will work for planes
omega blood's Avatar
Fullerton, California, United States
Joined Jan 2002
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canard cg would be nice. tired of doing the math.
http://www.palosrc.com/instructors/putte.PDF
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Old Jul 02, 2002, 10:40 AM
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Dick Huang's Avatar
Dallas,TX, USA
Joined Mar 1999
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GregT,
I have included a CG calc. program.
Dick Huang
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Old Jul 02, 2002, 11:00 AM
Registered User
Ithaca NY
Joined Mar 2002
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Yeah, mine wont be console based so it'll be much easier to use (i hope).

I'm doing this because I always find myself looking for formulas, and because im bored
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Old Jul 02, 2002, 11:33 AM
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London UK
Joined Sep 2001
105 Posts
Fast electric boat calculator

Here is a simple Excel spread sheet that I put together to calculate stuff for fast electric boats. If you click on the answer boxes you can see the formulas. Most of the calculations are also relevant to E.flight.

http://ann-neil.supanet.com/calculator.xls

Neil
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Old Jul 02, 2002, 12:05 PM
Registered User
Ithaca NY
Joined Mar 2002
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I've got a question on your current draw equation

you use:

3.6/time * mah = current draw



i would use:
Ah = current draw X total time

Whats the 3.6 for? Am i missing something?
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Old Jul 02, 2002, 12:29 PM
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United States, NY, Spencerport
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The 3.6 is a conversion factor. 3600 seconds/hour divided 1000 milliAmps/Amp gives 3.6, and cancels out the milliAmp-hour units of the battery capacity. The "time" is in seconds, so that cancels out too. All you're left with is Amps.
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Old Jul 02, 2002, 01:16 PM
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Ithaca NY
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ahh, yeah- guess i was thinking base units.
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Old Jul 02, 2002, 03:12 PM
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London UK
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I am glad mkirsh1 worked that one out first. I was having trouble remembering how I arrived at 3.6.

Neil
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Old Jul 03, 2002, 11:55 AM
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Ithaca NY
Joined Mar 2002
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Alright here is a little beta version of the first module (basic electricity formulas).

If there is a mistake in a formula, or bug, you can post it here.

I am serious about this program possible being unstable, I would save all my work before using it... I haven't tested it enough to make sure it wont crash- so be careful

I'm putting out such a simple version because I want you all to make sure everything works for me after stareing at something for a few hours you would be suprised how easy it is to miss simple mistakes. And there will be mistakes. Mistakes in formulas, actual math, input, output... you get the idea.

Next I will do CG sections (both with canard and without).
Again, post all questions/ comments/ suggestions/ complaints(?) here.




Download from: http://24.24.30.13/efc.zip

(if anyone has webspace that I could use for this, let me know- running apache on my win98 box isn't a very good idea ).



-------------
README

This is just a little collection of calculators to help you remember and use all the
little (sometimes not so little) formulas you find yourself using while
building/testing/flying your electric models.

All bugs / complains / suggestions / compliments may be sent to gregt@twcny.rr.com



NOTE: This software is provided "as is". That means it's free, no support is provided.
also note that this is a beta version, the code should be considered 'unstable'. Save
your work before running any of these programs, as I can't promise they won't crash your
computer (hopefully they wont crash your airplanes). The author of this software holds
no responsibility whatsoever for any damage caused by the use of this software.
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Old Jul 03, 2002, 01:18 PM
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Dick Huang's Avatar
Dallas,TX, USA
Joined Mar 1999
834 Posts
Greg
Got some more formulas for you.
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Old Jul 03, 2002, 01:20 PM
Registered User
Ithaca NY
Joined Mar 2002
73 Posts
yikes... could you provide a list of what the variables are at the top? Sooo many of them this is great, Ill put this stuff in once i figure out what the variables stand for.
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