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Old 03-21-2009, 11:52 AM   #16
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Originally Posted by Trips View Post
1/12th scale has been around longer than any other electric class. I've been involved since the first 1/12 scale cars came along. A LOT of evolution aloing the way to get what we have now. If you are interested in getting into 1/12, I'd respectfully suggest that you try it as it is... you won't be disappointed.



I'm pretty sure you can't get a 7.4 400 mah into the SMC 3.7 case... I dojn't see it geting much smaller than the existing 7.4v 4000mah LiPO's out there now.

1/12 used to be a 6 cell class. 7.2v was the norm for years. 4 cell came along in the U.S. when we started racing on small tight indoor carpet tracks in the winters. Summertime came, we went back outdoors and back to 6 cells. Europe ran 6 cell year round... Eventually, we evolved into a 4 cell only class. I don't see any logical reason to go back to higher voltage...

7.4 LiPO in 1/12 scales could be done, but it makes more sense to run single cell. A 23.5 would still be insane fast in a 7.4v 1/12 car. We'd need special 1/12 only motors to get the speed right... I'd guess something around a 26.5 or so. Now you'd need to buy a special motor (going rate for brushless motors is $80 neighborhood) that you'd only be able to use in 1/12th.

The single cell pack solves this problem elegantly... at around $50, the single cell pack is an easier buy-in than a new 1/12 only high turn motor. You only need one pack to go racing. Some speed controls run with no booster or rx pack. You can get a booster for under ten bucks if your speedo needs it, and it's plug and play. No complicated wiring. Most people who first get in to 1/12th scale say the cars are too fast... On the single cell, your existing 17.5 in a 1/12th chassis makes a VERY nice package... a little slower and a lot easier to drive than the 4 cell 17.5, not at all intimidating. Lightweight, less crash damage in an impact, hardly any tire wear. 13.5's on the single cell run about the same speed as current 4 cell stock 1/12ths, but again, less damage in an impact and greatly reduced tire wear.

The single cell really is the logical next step... I was not at all in favor of it when it first came along, but I was wrong. IT's hard to argue against something that works so well.
Trips, I too was VERY much against the one cell concept, and I'm still not sure if I'm sold on it, but you make the most compelling argument in favor of it that I have heard yet. I am a huge lipo fan myself. As mrrcguy said, if you gear each setup in it's "sweet spot", then the various motor/battery combinations are just too different performance wise to be ran together. If lipo (one way or another) is adopted in the 1/12 class, I just hope that lipo will then be the only option so that we don't have to argue over the performance differences associated with lipo/21.5 vs. nimh/17.5 etc..... or whatever the case may be.
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Old 03-21-2009, 12:39 PM   #17
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Trips- Thank you for your great replies and input on my post. But if all fairness I still feel that there is still alot of "ifs" regarding running one cell lipos. For instance, 1 cell lipo will work "if" you buy the right speed control. It will also work "if" you buy a booster. Also to make it work "if" you cut one wire here and don't turn it on. "If" the booster works but feel that you're dumping at the end of the run then you have to buy a reciever pack. You see where I'm getting at.

I think we should still do alot more testing. As several people pointed out that they are having great success running 2 cell lipo.
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Old 03-21-2009, 12:52 PM   #18
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When I first saw the 3.7 LiPo come along I HATED the idea of it. I honestly felt like it was going to be a horrible thing. My local track was one of the first to allow the 3.7/13.5 combo run alongside the 4 cell/17.5 cars... and everyone who made the switch was so happy with it that I decided to try it. One time out was all it took to change my mind. Same car, same setup, same tires, same layout, my lap times are identical to what I was running with the 4 cell/17.5, but instead of three or four great laps, a bunch of okay laps, and three or four awful laps, I can run a whole bunch of great laps.

If I had to come up with an explanation, I'd have to say that over the years 12th scale cars have been getting heavier and heavier... every time the cell capacity went up, the weight crept up... as the cars got heavier, driveability went away. it happened gradually... maybe too gradually to notice. I put the 3.7/13.5 setup on the track for the first time, and all of a sudden it felt like the last twenty years went away... I'm four laps faster in an eight minute run, but my lap times are no better than last week... just a WHOLE lot more consistent. The car is SO much nicer to drive, that I still have a hard time believing it.
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Old 03-21-2009, 01:15 PM   #19
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Originally Posted by zake540 View Post
.....For instance, 1 cell lipo will work "if" you buy the right speed control. It will also work "if" you buy a booster. Also to make it work "if" you cut one wire here and don't turn it on. "If" the booster works but feel that you're dumping at the end of the run then you have to buy a reciever pack. You see where I'm getting at.
So, having THE motor, THE speed control, and THE tire are brand new concepts to 12th racing??

A year ago, a lathe, dyno, $400 chargers, cell balancing equipment, and fresh batteries for whatever occasion was completely acceptable and almost required by the common racer. A $20 booster replaces a whole tub of stuff costing a grand.

It's the same amount of "headaches" costing a small fortune less.

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When I first saw the 3.7 LiPo come along I HATED the idea of it. I honestly felt like it was going to be a horrible thing. My local track was one of the first to allow the 3.7/13.5 combo run alongside the 4 cell/17.5 cars... and everyone who made the switch was so happy with it that I decided to try it. One time out was all it took to change my mind. Same car, same setup, same tires, same layout, my lap times are identical to what I was running with the 4 cell/17.5, but instead of three or four great laps, a bunch of okay laps, and three or four awful laps, I can run a whole bunch of great laps.

If I had to come up with an explanation, I'd have to say that over the years 12th scale cars have been getting heavier and heavier... every time the cell capacity went up, the weight crept up... as the cars got heavier, driveability went away. it happened gradually... maybe too gradually to notice. I put the 3.7/13.5 setup on the track for the first time, and all of a sudden it felt like the last twenty years went away... I'm four laps faster in an eight minute run, but my lap times are no better than last week... just a WHOLE lot more consistent. The car is SO much nicer to drive, that I still have a hard time believing it.
It's turning out that more people need to just try it. I hope when Nats are over with, real progress can be made.
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Old 03-21-2009, 03:56 PM   #20
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Originally Posted by zake540 View Post
Trips- Thank you for your great replies and input on my post. But if all fairness I still feel that there is still alot of "ifs" regarding running one cell lipos. For instance, 1 cell lipo will work "if" you buy the right speed control. It will also work "if" you buy a booster. Also to make it work "if" you cut one wire here and don't turn it on. "If" the booster works but feel that you're dumping at the end of the run then you have to buy a reciever pack. You see where I'm getting at.

I think we should still do alot more testing. As several people pointed out that they are having great success running 2 cell lipo.
There are some misconceptions in your reply...

1. 1 cell LiPO will eork "if" you buy the right speed control.

Actually, 1 cell LiPO will work with any speed control.

2. "If you cut a wire here and don't turn it on"

I'm not sure where this comes from, but there's no wire to cut. If you run a booster or rx pack, just leave the speed control switched off. Nothing complicated.

3. "If the booster works, but feels like dumping at the end you have to buy a receiver pack"

The dumping at the end feeling comes when running with no booster OR receiver pack. Either one, the booster OR the receiver pack takes care of it.

It really is that simple.

None of the sanctioning bodies have made any decisions yet as far as I know. Maybe 2 cell WILL turn out to be the answer. What I see so far is that the single cell works well. I'm not implying that 2 cell won't work, if it does, and it's better than the single cell, then I'd be in favor of going that route. It's still to early to say which way things will go.

I'd be willing to bet that if single cell does turn out to be the way we wind up going, then pretty soon new speed controls will have boost circuitry built right in.
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Old 03-21-2009, 06:15 PM   #21
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This thread is going the same way as the "Future of 1/12th Scale" thread did. So many people with opinions about something they have never tried. I'm like Trips, I didn't like the idea of single cell at first, but instead of getting on the internet I went to my workbench and set up a car with an SMC 3.7v pack and a reciever pack and took it to the track. The car drove great, felt really lively in the infield and with a 13.5 was just a touch faster than my 4 cell 17.5 car. To be honest, I still like the round cells, but they are on the way out. Single cell is a very good evolution of the class and ROAR will have it in the rules for next season
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Old 03-22-2009, 06:44 AM   #22
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Trips:
What is the weight of your 1/12th scale car with the single cell lipo?
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Old 03-22-2009, 07:00 AM   #23
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Just say "NO" to 2 cell lipo 12th scale.
The 3.7 lipo and 4-cell NiMH batteries provide more than enough power for these cars. Just my opinion....
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Old 03-22-2009, 07:05 AM   #24
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Just say "NO" to 2 cell lipo 12th scale.
The 3.7 lipo and 4-cell NiMH batteries provide more than enough power for these cars. Just my opinion....
Totally agree. We just need to get people to try it. Narrow minds are hard to crack.
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Old 03-22-2009, 07:18 AM   #25
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The ND guys I race with a couple times a year would be considered "old school 1/12 only grumpy old farts" by many...generally a GREAT bunch of guys (and Janet). They're debating adding 1s LiPo in their program but a point was strongly made by one of the OLDEST old farts that a) the LiPo cars must weigh the same 865g minimum they've established for their 1/12 cars (same as at Nats this year) and b) they have to drag a scale along with them so they can be weighed at any time.

Quick like a rabbit I whipped this up for my 1s car I raced in Denver last week:



Unfortunately, with all that (and a heavily reinforced body) I'm STILL under weight. Sigh.

What we found in the race at Denver:

The 4-cell GTB is definitely plug-n-play with 1s. I used a $6 voltage booster (simple plug in-line between esc and receiver).

The Tekin works well with a simple work-around that has been discussed elsewhere. Honestly, making the charger harness for your batteries was harder.

The LRP/Nosrams had some "challenge" that we didn't get sorted out at the track. It will probably be something simple to correct like the Tekins were.

All-in-all...I wasn't "for" the 1s either until I tried it. Now I've raced it exactly once and am completely sold on it. I'm back home and have a club race today where I'll have to race 4-cell again (still) and I'm really just not into it any more.
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Old 03-23-2009, 07:16 AM   #26
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Quote:
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Trips:
What is the weight of your 1/12th scale car with the single cell lipo?
684 grams with an LRP 13.5
672 grams with a Trinity Duo 17.5
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Old 03-23-2009, 07:54 AM   #27
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Much of what's here has been discussed on the old thread.

These threads always ignore the fact that there are several classes in 12th. Having run both single cell and 2 cell in mod I can say for a fact that single cell is the way to go. Dumping isn't good for LiPo so the cells we go to need to work for all of the classes. 2 cell cuts the capacity in half.

Maybe if the classes slowed down a little we'd be able to get more than 15 or 20 guys to run mod at the big races. Plus the slowest class might actually be a good speed for beginners.
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Old 03-23-2009, 07:58 AM   #28
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The ND guys I race with a couple times a year would be considered "old school 1/12 only grumpy old farts" by many...generally a GREAT bunch of guys (and Janet). They're debating adding 1s LiPo in their program but a point was strongly made by one of the OLDEST old farts that a) the LiPo cars must weigh the same 865g minimum they've established for their 1/12 cars (same as at Nats this year) and b) they have to drag a scale along with them so they can be weighed at any time.

Quick like a rabbit I whipped this up for my 1s car I raced in Denver last week:
I LOVE your solution, but I disagree with the 865 weight minimum. As a long standing member of the "grumpy1/12 scale old fart" group (31 seasons on carpet and counting) I ahve to say that maybe the biggest eye opener for me has been going from a heavy NIMH car to a light LiPO car. I put that LiPO car down and it was like 20 years had disappeared...

I'm pretty convinced that as the capacity and weight of the round cells has crept up oveer the years, it gradually chipped away at the driveability of the cars. So gradually we just didn't notice it happening.... A few laps with the lighter LiPO car and the light bulb went on over my head...

Your post in another thread where you made the "dumptruck vs. sportscar" metaphor was right on the money. I'd just as soon NEVER Race at 800+ grams again.

Quote:
Originally Posted by Scottrik View Post
What we found in the race at Denver:

The 4-cell GTB is definitely plug-n-play with 1s. I used a $6 voltage booster (simple plug in-line between esc and receiver).

The Tekin works well with a simple work-around that has been discussed elsewhere. Honestly, making the charger harness for your batteries was harder.

The LRP/Nosrams had some "challenge" that we didn't get sorted out at the track. It will probably be something simple to correct like the Tekins were.
I haven't seen the need for any workaround with the RS here... I put a switch inline, mainly for the marshals to be able to turn the car off easily in the event of a problem, but it worked just as well without it. No less plug and play than the Novak.

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All-in-all...I wasn't "for" the 1s either until I tried it. Now I've raced it exactly once and am completely sold on it. I'm back home and have a club race today where I'll have to race 4-cell again (still) and I'm really just not into it any more.
Amen.
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Old 03-23-2009, 08:25 AM   #29
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my 2 cell lipo car wieghs in at 550 grams. that's better then 800g, right? and runtime is not an issue. 10 min. minimum w/ a cheapo $10 lipo.

once you run at 550 grams, you'll never want to run at 800. A mod 1/12 at 550 grams is like driving a shrunken formula one ferrari. and that's goooood.

The real trick here is getting all the 1/12 scale guys to realize that 540 motors were designed for 1/10 cars. strapping a big block chevy into a go-cart is not ideal for handling. Originally, 1/12 DID have smaller motors when they were introduced, and they are waay more powerful now.

I've heard the reasoning is that the motors between classes are interchangable. NOT. all the fast guys will buy special light weight motors ala Novak Light to work around the real problem of excess weight. And the extra weight of the motor is in a terrible place from a handling standpoint.

Bottom line: the motors need to be down sized to ~380 size. This is the time to set the future of 1/12 as there is massive opportunities for improvement. Single cell? No. 380 two cell (or 3 cell!) lipo? YES YES YES

Here we go again.....
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Old 03-23-2009, 08:34 AM   #30
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I disagree with having the heavier weight limit placed on the lipo cars as well. For the 2010 rules I'm pretty sure both the local clubs will allow 1s lipos and they will probably allow the lighter chassis as that should help decrease tire wear.
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