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-   -   How to limit power for regulated racing class? (https://www.wattflyer.com/forums/showthread.php?t=42554)

HugoW 01-07-2009 01:07 PM

How to limit power for regulated racing class?
 
Hi,

on the Dutch model plane forum I often visit, there is a discussion on making a Q500 pylon racing class for electrics. Since there won't me many competitors to start with, we want to fly amidst the regular smelly class. At similar speeds. Now it's easy to make a hugely fast plane, so we want some form of power regulation. Which also would mean expensive set-ups won't be a huge advantage. Simple question, how does one (simply, effectively and cheaply) limit the power? Any idea will be welcome, so please shoot!

Hugo

Sky Sharkster 01-07-2009 01:13 PM

Limited or Unlimited?
 
Hello Hugo,
I think the most simple and easiest to enforce would be voltage.
For example, if you had a limit of 8.4 volts, models with either 7 conventional cells or 2S LiPos could compete. The liPos would have lower voltage (7.4V) but would be much lighter.
Or, 12 volt limit. 3s LiPos and 10 cell "can" cells could compete.
Just an idea!
Ron

HugoW 01-07-2009 02:51 PM

Yeah, I'm fiddling around with a 15V regulator (for 5S lipo, so voltage drop under load due do cheaper pack doesn't matter too much), that goes poof and lets out smoke over 65A. And as we all know, electronics run on smoke, once the smoke is out they stop functioning. You should tap of the BEC prior to the regulator so you can glide back if you over-amped it.

But there are undoubtebly more options, so don't hesitate to ventilate!

Hugo

slipstick 01-07-2009 02:57 PM

I guess you want to be competetive with the IC planes but not loads faster, or they won't let you play with them ;).

You could always have a standard prop size and maximum tacho reading. The biggest problem I can see there is that it won't let people try different options like larger prop turning slower...but I don't think that's a big deal with a racing class - small prop with high pitch will always rule ;).

Another alternative that may be practical is a maximum battery size (voltage and capacity). Since I guess you'll probably be flying fixed length races then that will be all you need to limit power. If anyone uses too much power they won't finish the race. If you really wanted to level everything off you could even arrange for batteries to be handed out to competitors at the start of each race so there's not even any possibility of anyone spending a fortune getting super-special batteries.

I'm sure there are plenty of other possibilities ;).

Steve

HugoW 01-07-2009 03:04 PM

You're absolutely right; within current rules we can fly loops around the IC planes...

Besides making it competative, we're also looking into cost. I buy el-cheapo packs from HC, same V/mAh packs from expensive brands will perform better. But we don't want the ritchest dude/dudette to win because of depth of his/her wallet.

Standard prop size and rpm reading would be an option, just make sure people don't trim their throttle channel back before the test.

Hugo

eflight-ray 01-07-2009 04:41 PM

The International electric pylon racing class is F5D, rules and regulations are controlled by the FAI.
Here's a link to one site, http://www.chiners.pwp.blueyonder.co.uk/

I know you are considering something simpler and perhaps cheaper, but often once a new class is established, fliers who want to fly in competitions may want to move up to a properly regulated class, such as F5D.

Competitive fliers will soon find every way possible to win, that usually means changing the rules each season to compensate for those who will spend the most. It's happened a lot in various electric competition classes.

The other possible way might be to revive the old handicap racing where just about any model was allowed but their handicap was adjusted after each race. The type of model could be restricted to say Q500 size models, but a good handicap system should eventually sort out those who want to keep spending money to try and win.


Just an idea.

slipstick 01-07-2009 09:32 PM


Originally Posted by HugoW (Post 539253)
Besides making it competative, we're also looking into cost. I buy el-cheapo packs from HC, same V/mAh packs from expensive brands will perform better. But we don't want the ritchest dude/dudette to win because of depth of his/her wallet.

That one's easy. Standard connectors, ALL batteries have a number issued by the organiser. The competitors draw a number at random before each round and that's the battery they have to use. People can bring along expensive packs if they want to but it might be another competitor who gets to use it in the race :).

Of course if you set your plane up to use a little less power than is really available and then buy a cheap battery there's a fair chance that whoever draws your battery won't even finish the race...but that would be sneaky ;).

Steve

ron_van_sommeren 01-08-2009 03:13 PM


Originally Posted by slipstick (Post 539428)
That one's easy. Standard connectors, ALL batteries have a number issued by the organiser. ...

And the same method for the motors?

Vriendelijke groeten ;) Ron


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