Suggested Electric 1/8th section rules - RC-Monster Forums

Marvin · **Suggested Electric 1/8th section rules -** 10.30.2009, 06:28 AM

I've written a set of draft rules to go alongside the BRCA rallycross rules You'll need to go to the 1/8 rallycross section and click on BRCA Rallycross Rules 2009

Here they are.

Any comments/suggestions are welcome.

wallot · 10.30.2009, 11:24 AM

Looks good. Rules, but very open.

brushlessboy16 · 10.30.2009, 11:59 AM

Looks good :)

Marvin · 10.30.2009, 12:12 PM

That's good to hear good positive feedback so soon.

stum · 01:59 AM

Looks fine, but isn't that just overstating the obvious? Most tracks already work this way, only large events such as Pro-Series and ROAR events have yet to adopt electric cars into nitro classes provided they meet standard requirements. These large events will eventially have a 1/8 electric truggy class, just as they added a 1/8 buggy class this year. It's nice in many ways to run against the nitro's but when it comes down to the 30+min mains.. the 3x10min format keeps long battery swaps from being a huge factor in the outcome of the race. If you don't have enough racers for a fun class, you just deal w/ the battery swaps and hope for the best :) I picked up two 6500 35c hyperion packs for racing this year and I have one 9000mah SMC pack to help reduce swaps to just 1 per long event... the 9k 4s pack will just make it for a 20min main, anything longer requires a swap out (maybe 2 for a 45min main)

What's_nitro? · 10.31.2009, 01:55 AM

It's a great start, but while reading I got the impression that it was a tutorial rather than a set of rules. IMO I'd leave out most of the "suggestions" and/or "recommendations".

wallot · 10.31.2009, 03:45 AM

high capacity batteries are still just too heavy for racing. it makes a huge difference in handling when i run 3300mah vs. 5000mah packs (almost 200grams difference).

more shorter mains is the way to go till batteries can keep up.

Marvin · 10.31.2009, 04:32 AM

I wrote it as guidelines for clubs/ the national organisation in the UK, where 1/8 electric isn't popular yet, and when a club is faced with electrics, they may do different things. I tried to write this in advance of widespread electrics racing, so that everyone has the same set of rules. Therefore for an electric racer who goes around different tracks, they would always experience the same rules.

Many UK clubs will be unfamiliar with the format of 1/8 electric. That's the only reason I put lots of recommendations and suggestions in there.

I wasn't too sure about the length of the mains. I was thinking, well, the norm in America is 10 minutes, but it just seems a little short to me (I race 20 minute finals, so it is of course a normative statement). I thought that for 15 minutes, you could use a 4S 5000, or a 5S 4000 or a 6S 3300. All of these are common size batteries (apart from the 5S, but there are many capacities just around that), and it keeps the spirit of 1/8 off-road, where it is a bit of endurance racing thrown in.

Obviously though, I kept it open for the club to decide - minimum 8 minutes.

stum · 08:46 AM

Quote:

Originally Posted by wallot

high capacity batteries are still just too heavy for racing. it makes a huge difference in handling when i run 3300mah vs. 5000mah packs (almost 200grams difference).

more shorter mains is the way to go till batteries can keep up.

You must be using 6s to get away w/ a 3300 pack...

My truggy weight is perfect iMO w/ the hyperion 4s vx 6500 packs, the packs around ~685oz, and they give me a little more run time than the 5s 5000packs that I used last season racing. Changed motor from the 2.5d to the 1y as well for this next year to keep a bette rpm range. The 4s 9k packs are not as highly rated as the hyperions so to be honest the weight difference is marginal (120oz more about). The truck feels a little fat on the track with the 9k's but to save a battery swap for me it's well worth the handling differences as I'd loose more time w/ a battery swap.

14.8v * 6500 = 96200
18.5v * 5000 = 92500
14.8v * 9000 = 133200
22.2v * 3300 = 73260
22.2v * 5000 = 111000

your 3300 pack wouldn'd last me long enough for anything other than qualifiers since I race w/ nitro's in longer a-mains 99% of the time. Id guess that 6s 5k pack was nearly 100oz or more bigger than my 6500 packs as well. Nice thing is for the long amains w/ my 9k packs not only am I getting more run time than a 6s 5k pack but the weight is about the same.

What's_nitro? · 10.31.2009, 01:00 PM

Quote:

Originally Posted by Marvin

Many UK clubs will be unfamiliar with the format of 1/8 electric. That's the only reason I put lots of recommendations and suggestions in there.

I see. So you and Neil are the only ones over there who run electric?

Marvin · 10.31.2009, 03:16 PM

Obviously there are others too

, but I reckon there are less than 50 brushless conversions that are raced in England. Spread between all the different clubs, and there aren't many at each club.

Matthew_Armeni · 10.31.2009, 04:03 PM

On rule number 4 you may want to add that 3rd channel mixing is ok (I think most 1/8th scale rules say only 2 channels may be used) for those running mechanical brakes.

wallot · 10.31.2009, 04:10 PM

no chance to make 15 minutes with 5S 4000mah

If the track profile is right I can make 10 minutes with 3300mah and 15minutes with 5000mah if I dont push it too hard.

If we had 15minute mains as standard I would probably go for 5500mah hyperions to be sure and not to stress the batteries too much and it would make my truck quite heavy.

My truck is quite light - 4200grams with 3300mah and 4400g with 5000mah RTR. (my nitro mugen used to be little bit under 4500g rtr but with heavier wheels so I guess about 4400g with VTR prolines I run now and it just was not agile enough to my liking as my lighter BL truck)

With lighter batteries the truck handles much better except for tracks with very low traction where heavier batteries help with traction.

Hyperions G3 35C/65C 3300mah 5S have no problem pushing my mugen for 10 minutes. based on eagle tree data they are at similar level with 5000mah 30C/40C zippy flightmax

My Neu 1415 has about 10-15% less power consumption compared to Tekin T8 powered truck fellow racers run. Sure some of it is driving style as I am very smooth on throttle.

IMHO 15 minutes is too much unless you want to compromise on car handling or push batteries to the limit.

Marvin · 10.31.2009, 06:19 PM

Wallot, I run a 5S 5500mAh Hyperion pack in my XB808 (weight ~3750g) and I can get 23-24 minutes on the track. Last week was my last race of the year, and I qualified 5th in the A-final, and finished 4th after 20 minutes. No stops or similar. I then ran the car for about 3-4 minutes in a practice session just after the race, on the same charge before the LiPO cut off kicked in.

According to my calculations, 18.5 * 5.5 is 101.75Wh. Multiplied by 0.75 (to get the Wh required for 18 minutes (3/4 of 24)) is 76.3125Wh, which divided by 18.5 is 4.125Ah. That's for 17-18 minutes, and you only need ~16.

In a truggy, more is needed of course as they are heavier, but those are all good for 15 minutes in my buggy.

Obviously it is personal opinion which length is right. I guess 10 minute will win through in the end. I'll alter it accordingly. Maybe split the difference at 12 minutes?

I'll clarify the 3rd channel point - thanks for pointing that one out.

wallot · 10.31.2009, 06:49 PM

3750g is very heavy for a buggy :) my nitro D8 is 3500g RTR, nitro RTR MBX6 is 3350g -3400g RTR

lighter car = later breaking, faster through corners

I would start with 12min max and adjust depending on car setups at the race (that what we did this year. started at 6 minute runs, then went to 8 minute runs, next year aiming for 12)

It still should be fun and not about who has the most money to buy the best equipment that can handle longer mains.

What I like about BL racing is the very low maintenance compared to nitro.

It is not a mainstream class and it will not for a while so it should be fun.