|Clifford Stone||30/08/2012 17:39:41|
|243 forum posts|
I'm looking at Club 2000 electric pylon racing, the idea is to return to my roots of pylon racing, more for the fun, with out to much concern to be truly competitive on a personal front.
However, one needs to work out the kit required?
Motors used: Turnigy SK3536 1400kv or the new Turnigy NTM 3536 1400kv. Props used are Radio Active 8x6.
The above are not a problem, ESC is likly to 80A!!! not becase that will be required, better power flow, they say?
My concern is the batteries, 2200, 14.8v, 4s, 45c, its the 45c that I don't understand, is it pratical to use a 35c? Flying time 2 to 2.5 minuites max! At £36 ago, the potential requirement of 8 batteries is a bit steep? Alternativly 4 betteries and charging on the field, practical?
I do have a source of 35c batteries at a reasonable price?
Sorry its a bit vague, but I'm a bit muddled my self, I think the 'c' figure has something to do with current draw?
Edited By Clifford Stone on 30/08/2012 17:41:02
|Chris Bott - Moderator||30/08/2012 17:47:33|
6709 forum posts
Clifford the "C" rating does show how much current draw the battery is rated for. But it is meaningless without a figure for the capacity of the battery.
To find the current that the battery is rated for, multiply the capacity (in Ah) by the "C" rating
So a 2200mAh (2.2Ah) battery that is rated at 45C is actually rated for 2.2x45 = 99A
It's generally better to run a battery at less than it's C rating though, to extend the life of the battery.
|Gordon Bushell||30/08/2012 17:59:34|
|99 forum posts|
|The higher the c rating, generally means the lower the voltage sag in the battery.|
I suspect that means lower internal resistance in the battery, and thus less power wasted in the battery for a given current draw.
|Chris Bott - Moderator||30/08/2012 18:09:25|
6709 forum posts
That will be the reason for using very high C rating batteries Gordon yes, I hadn't thought of that.
So in Cliffords case he can probably use 35C batteries but at the expense of a little bit of performance. (and possibly a bit of a reduction in life too).
|Mark Powell 2||31/08/2012 04:46:15|
|430 forum posts|
And these things are even faster than the top IC pylon class!
|Gordon Bushell||31/08/2012 07:28:57|
|99 forum posts|
|Whether good piloting would make up the difference or not I don't know. I think it would be interesting to find out. I suppose it depends on the actual current drawn.|
If the flying time is 2 mins flat out, and you go from fully charged to empty, that suggests a continuous 30c discharge.
I've never seen pylon racing with models.
|Clifford Stone||31/08/2012 11:00:20|
|243 forum posts||
In the good old days, a good pilot with a good model was always favourit, however a good pilot with an average model was always in 2nd place waiting for a mistake!
The Club 2000 electric models are a tad faster than their ic counterparts for the first 7 laps, probably half a lap ahead by lap 7, laps 8, 9 and last lap10, is where it evens out and the battery starts to 'sag'. Looking at the heat times for this year an average race time for ten laps, thats flat out running time of 74 seconds! There is no pre run, warm up time, as is normal for ic, 'as the flag drops' its full power ON!!!!
Curently they race them in the same heats as the ic models, so a direct comparison is easy to make, 3 or 4 models trying to fly in the same piece of air space . . . As with all forms of racing there is only one 'ideal line' so to have that extra bit of umph at the start is good to get in front and away from potential trouble. Mid airs are not common, as aircraft have the advantage of 3D spacing, but good piloting is still essecential, if you spend time climbing to the first pylon, that slows the model . . . but one also has to be aware, there is a low fly rule, about 20ft! and that the run to the next pylon needs to be at a negative, allbeit tiny angle, to build speed. This is where a good pilot can gain time, getting the turn and flight angles right to mantain speed . . . I would liken it to an F1 race car driver getting the apex of a corner right, its worth precious 10ths.
As you say Gorden, it would be interesting to find out?
Does battery sag occour at the same point regadless of 'mAh'? ie, will a 2800mAh ratted battery sag latter in the full power draw than a 2200mAh?
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