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Old 02-19-2009, 12:00 PM   #196
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Originally Posted by trout74 View Post
+1 with my setup.
It's pretty funny, to watch a "Seasoned" nitro driver, FUMBLE all over the place because he's used to something so much slower!
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Old 02-20-2009, 02:35 AM   #197
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Just to clarify. I assume your T4 runs a 2s 8000mah pack yes? If so, the capacity of a 5s 2500 pack is only 20% smaller than the 2s 8000mah.
20% less? I don't think so. Try 2500 divided by 8000= 31%, more like 69% less pack or roughly 2/3 less pack. I admit the first claim i did was wrong, been a while since i had to figure percentages. I don't see how you get 20%less, When the pack is 1500mah smaller than half the 8000. 20% less is 1600 mah or 6400 mah pack, I'm still 4000 mah less than that. Are you going by some formula for using voltage and Mah for potential power output over time? If so show what you got, I never seen that formula, Id' like to use it

And Yes the T4 runs a 2s 8000 pack, sorry for not clarifying that. I figure because of the comparison, people would assume it was the 2s.
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Old 02-20-2009, 05:54 AM   #198
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Originally Posted by crazyjr View Post
20% less? I don't think so. Try 2500 divided by 8000= 31%, more like 69% less pack or roughly 2/3 less pack. I admit the first claim i did was wrong, been a while since i had to figure percentages. I don't see how you get 20%less, When the pack is 1500mah smaller than half the 8000. 20% less is 1600 mah or 6400 mah pack, I'm still 4000 mah less than that. Are you going by some formula for using voltage and Mah for potential power output over time? If so show what you got, I never seen that formula, Id' like to use it

And Yes the T4 runs a 2s 8000 pack, sorry for not clarifying that. I figure because of the comparison, people would assume it was the 2s.
8000 x 7.4 = 59200
2500 x 18.5= 46250

59200 - 46250 = 12950
12950 / 59200 = .21875 (21.875% less total energy in the 5s 2500 pack)
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Old 02-20-2009, 05:56 AM   #199
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Quote:
Originally Posted by crazyjr View Post
20% less? I don't think so. Try 2500 divided by 8000= 31%, more like 69% less pack or roughly 2/3 less pack. I admit the first claim i did was wrong, been a while since i had to figure percentages. I don't see how you get 20%less, When the pack is 1500mah smaller than half the 8000. 20% less is 1600 mah or 6400 mah pack, I'm still 4000 mah less than that. Are you going by some formula for using voltage and Mah for potential power output over time? If so show what you got, I never seen that formula, Id' like to use it

And Yes the T4 runs a 2s 8000 pack, sorry for not clarifying that. I figure because of the comparison, people would assume it was the 2s.
It's not as simple as you think. Think of it as adding up each cell in the pack to a total, not how they are wired. Doing this represents total stored energy independent of voltage.

2500 5s pack = 12,500mah total.
8000 2s pack = 16,000mah total.

edit: Jeff beat me to it!

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Old 02-20-2009, 05:23 PM   #200
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Originally Posted by jhautz View Post
8000 x 7.4 = 59200
2500 x 18.5= 46250

59200 - 46250 = 12950
12950 / 59200 = .21875 (21.875% less total energy in the 5s 2500 pack)
Quote:
Originally Posted by thuren View Post
It's not as simple as you think. Think of it as adding up each cell in the pack to a total, not how they are wired. Doing this represents total stored energy independent of voltage.

2500 5s pack = 12,500mah total.
8000 2s pack = 16,000mah total.

edit: Jeff beat me to it!

I stand corrected, thanks
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Old 02-22-2009, 08:50 PM   #201
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So far, 20 posts on this page and no talk of rules.

That tells me we don't much care for rules.
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Old 02-22-2009, 09:38 PM   #202
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There needs to be rules put in place or the people with money will be allowed to motor up in the heats & motor down for the mains. On a large track these buggies can hit over 70mph w/ the right motor & there are no walls for turn marshalls to hide behind like in on road. This means that when the super fast buggy misses his jump & hits pedro in the head the buggy could very well be doing lethal damage to pedro. The nitro buggies are already dangerous enough marshaling & there is no point in making them faster. A .21 nitro has been more then fast enough for people for a very long time & there is no reason to push them faster. If you want to stand around while 7lb. objects fly by at 70 mph then change hobbies to real racing because it will be just as dangerous if not more dangerous. I believe that these buggies should be limited to running a 1512 2.5d on a 4s lipo. This setup has been proven to be slightly faster then a high rev nitro mill w/ more bottom end then a good 3 port motor. If you ask me that makes for the perfect setup for buggies or truggies. They are effecient, durable, & just a smidge faster then the other option. Not to mention the setup isn't as hard on the buggy so stuff will last longer & racers will be happy. This class doesn't need to turn into 1/10th tc & it could easily do so in a hurry.
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Old 02-23-2009, 02:47 AM   #203
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Originally Posted by party_wagon View Post
There needs to be rules put in place or the people with money will be allowed to motor up in the heats & motor down for the mains. On a large track these buggies can hit over 70mph w/ the right motor & there are no walls for turn marshalls to hide behind like in on road. This means that when the super fast buggy misses his jump & hits pedro in the head the buggy could very well be doing lethal damage to pedro. The nitro buggies are already dangerous enough marshaling & there is no point in making them faster. A .21 nitro has been more then fast enough for people for a very long time & there is no reason to push them faster. If you want to stand around while 7lb. objects fly by at 70 mph then change hobbies to real racing because it will be just as dangerous if not more dangerous. I believe that these buggies should be limited to running a 1512 2.5d on a 4s lipo. This setup has been proven to be slightly faster then a high rev nitro mill w/ more bottom end then a good 3 port motor. If you ask me that makes for the perfect setup for buggies or truggies. They are effecient, durable, & just a smidge faster then the other option. Not to mention the setup isn't as hard on the buggy so stuff will last longer & racers will be happy. This class doesn't need to turn into 1/10th tc & it could easily do so in a hurry.

I don't think the "motor up" concept works. Ive been racing my EP 1:8 buggy and I've noticed something like a "law of diminishing returns" in play when it comes to power. Seems the more power the less consistent traction is and the average lap time goes down quite sharply. I find myself cranking up that punch control to slow down the spool up and make the car smoother and in a sense- slower resulting in quicker lap times. Limiting motor size to the one you suggested would be fine in theory cause IMO it is more motor than a top driver needs but it would be a pain in the behind for race organisers to police and update as new motors get released and comparisons between cell count and motor size need to be calculated and or judged fairly. I just don't think the big motors will win races consistently and race officials can easily change track layout to remove the unfair advantage of a big motor.

Perhaps we can propose safety rules that eliminates the need to scrutineer cars and or set max limits on power to make it safe and competitive at the same time.

1: No double jump rules determined by track officials if two jumps can be linked by a very fast car creating a severe danger spot in-between crests or at the downramp of the second jump.
2. Perhaps a legitimate Safety Induction for marshalling, driving and pit practices now that we have lots of big lipos being knocked around. Actually make it official with a rules handbook and questionaire instead of putting it in a book and closing it once its written.
3. Flashing beacons for marshalls at known blackspots on the track after jumps and in-between doubles - activated by the marshal and backed up by the race director who sees the beacon warning drivers to drive with care in that area and stay on the ground (not airbourne).
4. Maximum straight length to slow down the top speeds. (We're not drag racing so a chicane or rythm section is not going to upset anyone.)

Just ideas guys. (Now where did I put my polycarbonate chest plate and stack hat?)
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Old 02-23-2009, 05:59 AM   #204
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... or we could just keep things as they are now since it's working perfectly fine.
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Old 02-23-2009, 06:12 AM   #205
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Some very interesting topics of debate in this thread all based on what rules should be in place. I being a Canadian racer as well as a director for a western Canadian off road series look to you guys down south to get an idea of what will work best for classes and this one is definately a class I am taking a close look at.

Locally the class is small as of yet but I fear without a set of class rules in place we will end up with power hungry over motored buggys that could pose a danger to marshals and or spectators.

I think there needs to be guidelines set up as to mAh capacity vs. cell count max based on a motors ability to operate around 29,000 rpm for 18 minutes if it's decided that 15 minute mains are best or simply leave it at triple 10 minute mains based on 5k 4s, 4k 5s or 3400 6s. Heat is always an issue as you lower cell counts.

I wonder how many of you barely making 15 minutes are running esc and steering servo only compared to someone running steering servo, brake servo and esc with no brakes to achieve lower temps and longer run times?
I am shocked I have seen no mention of brake servo in use as it works far better for brake bias and keeps the motor temps way down.
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Old 02-23-2009, 06:44 AM   #206
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Leave it as is RC Pro has it all under controll.
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Old 02-23-2009, 12:58 PM   #207
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You guys are stupid & iresponsible if you do not want to accept the fact that these buggies are already dangerous to marshall for & even more dangerous if they go faster. If you have to reach for your punch control then going w/ a 2.5 on a 4s lipo should not be an issue for you. Just because you have no throtle control skills doesn't mean an experienced 2wd buggy driver can not lay down 5kw of power on a good day. Just because they are an experienced driver doesn't mean that they will hit their line & not hit a section of the track wrong sending their buggy flying at a marshall. If you think dodging an 1/8th scale at 40mph is tough then try dodging one at 70 mph. I'm going to assume that the people who are trying to make the safety isn't an issue argument also send their little kids out to turn marshall the truggies too. If you don't fix the issue at the start then it become much tougher to fix the issue later on down the road. If you are curious as to how much more energy a buggy carries going 60mph instead of 45 mph then think about this. A buggies energy is proportional to the square of it's velocity. This means that a buggy going 70mph will hit with more then double the force of one going 50 mph.

So, here is why there should be a limit.
safer
longer run times
longer car life
less wear on track
nitros can compete so small tracks can run the classes togather.

I figured this thread could get started up since people will do anything to win since they already do it anyways. Exspecialy when a paycheck could be riding on the outcome of their performance.

http://www.rctech.net/forum/nitro-of...ml#post5469536
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Old 02-23-2009, 01:56 PM   #208
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As someone else already said, set cell count max limit based on motor selection. IE 2200-2650 kv max 4 cells, 1800-2200 kv 5 cell, 1200 - 1800kv 6 cell, below that- 8 cell?? Something like that anyways. Then no one will be excluded because of what gear they already have (unless they have a 2650 castle with 6s lipo right now), no one can go stupidly fast, it is easy to tech. Who cares about capacity, run whatever.
Anyone who says they race and their truck goes 70 mph is a liar or just a basher that races his buddy.
The funny thing is, everyone complains about ROAR deciding stuff for everyone else, how many posts in this thread?
2 things are obvious: RC PRO and ROAR need to make a stand somewhere, and your not going to make everyone happy.
Our track will just go with common sense.
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Old 02-23-2009, 02:06 PM   #209
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Even if you limit cell count to 4S, I can still gear my death missile for 70 mph. So go ahead, the idiots will still be idiots, even on 4S.
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Old 02-23-2009, 02:45 PM   #210
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Even if you limit cell count to 4S, I can still gear my death missile for 70 mph. So go ahead, the idiots will still be idiots, even on 4S.
+1

And besides that, good luck actually getting your buggy up to speeds like that on even the big tracks. There just isnt enough room. Yes they can get to speeds a little faster than a nitro, but 70mph on a track is not even realistic. In a parking lot yes you could hit those kinds of speeds, but thats not what we are talking about.

Talking about speeds that high is just BS to try and scare people IMO.
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