The future of 1/12 scale
#332
Perhaps an offshoot of this thread could be, "How the heck do you get it through to people a better way to do things without making them dig in?" As I age I see it always comes down to politics and marketing. You can have the best idea or product in the world, but it won't go unless you "do the dance". It's all in the politics and marketing, sad really.
#333
For the oval guys it's about the same as 4 cell 13.5 or a little faster. Probably not the best thing to get new people to start racing.
Higher voltage will need to have one of two things. Nonstandard motors or limited capacity. Nonstandard motors is a bad idea as far as I'm concerned and anything over 21.5 is going to be a real pain to gear. Limiting capacity will limit the speeds by causing the cars to dump.
Nothing starts a battery war like having less capacity than what you need to finish. Plus, we all know that lipo's just love to be dumped completely.
Higher voltage will need to have one of two things. Nonstandard motors or limited capacity. Nonstandard motors is a bad idea as far as I'm concerned and anything over 21.5 is going to be a real pain to gear. Limiting capacity will limit the speeds by causing the cars to dump.
Nothing starts a battery war like having less capacity than what you need to finish. Plus, we all know that lipo's just love to be dumped completely.
#334
Tech Elite
iTrader: (49)
I consider myself a scientist. Controlled testing of a single variable while holding everything else as controlled as possible is critical in these situations. I agree. So here is my experience with a 2 cell lipo in a CRC pan car and a 21.5
Problem/Question:
Will a 21.5/2 cell lipo powered car perform comparably to a 4 cell 17.5 powered variant.
Hypothesis:
If the motor's power is reduced to a 21.5 and the battery's voltage is doubled, then the cars speed and handling will be a little faster than 4 cell/17.5; perhaps more like 13.5 4 cell.
Equipment:
CRC WGT car
Jaco Spec tires
Novak 17.5
Novak 21.5
Ener-G cells
CORE R/C 7.4 v 5k lipo
Indoor carpet facility
Test & Data:
I ran the car with a 4 cell pack and a 17.5 for 4 or 5 packs making small changes to the center spring and sauce time/amount to get a baseline figure. The car doesn't belong to me so I wanted to be sure I had a good amount of laps to get a decent fast and average laps total. I hovered around a 12.6, with a 12.4 FL. The motor was geared for lap times and was coming off around 150*
That same night I then swapped out the 4 cells and 17.5 for the 21.5 and the Lipo. I ran about 4 lipo packs through it with same set up that gave me the FL with the 17.5. The data here is misleading so please red to the end for the explanation; the numbers don't tell the whole story. I was only able to muster a 12.5 FL and my average was a good second above that. At the time I tested this our track layout was new and the limiting factor to the lap times was the traction. With a 17.5 I could hang on to the car and get it around consistently. The 21.5 with the 2 cell felt like a 4 cell car with a 10.5 in it to me. It had so much rip, I couldn't control it consistently on the low grip. I geared it for the fastest lap times as best I could, and it was coming off at 150* as well. It was clearly obvious to me that counting on a 21.5 on 7.4 volts to act as a entry level speed was out of the question. Maybe a 31.5 would work . . .LOL
Conclusion:
The 21.5 lipo option is much to fast for the masses, let alone comparable to 17.5 4 cell. It appears the voltage gained is much more dramatic than the loss in motor power.
#335
I'll stick with the 3.7V solution. Battery Packs already exist as I pointed out with the TeamCheckpoint and SMC is already has pack designed for 4-cell cutout trays comming very very soon.
PRS (Precision Racing Systems) has already annonuced that they will supply pinions and spurs needed in Single Cell setups. If new sizes are needed they will make new sizes.
With 3.7V testing in oval, the gearing is only about 10 teeth higher on a 13.5 Oval car and PRS already makes pinions to 65teeth and Spurs as small as 72T. So just to put that in perspective. Using the largest Pinion and Smallest Spur PRS makes with a tires trued to 42mm rollouts up 119mm are possible and more than enough to proper gear a 1:12 for the back straight-a-way!!!
With the lower weight limits and proper gearing a 13.5 3.7V LiPO Oval car can be just as quick as a 21.5 7.4V LiPO car. So with a 17.5 motor, stock speeds can exsist without the worry of out-classing racers as a 7.4V solution would present.
PRS (Precision Racing Systems) has already annonuced that they will supply pinions and spurs needed in Single Cell setups. If new sizes are needed they will make new sizes.
With 3.7V testing in oval, the gearing is only about 10 teeth higher on a 13.5 Oval car and PRS already makes pinions to 65teeth and Spurs as small as 72T. So just to put that in perspective. Using the largest Pinion and Smallest Spur PRS makes with a tires trued to 42mm rollouts up 119mm are possible and more than enough to proper gear a 1:12 for the back straight-a-way!!!
With the lower weight limits and proper gearing a 13.5 3.7V LiPO Oval car can be just as quick as a 21.5 7.4V LiPO car. So with a 17.5 motor, stock speeds can exsist without the worry of out-classing racers as a 7.4V solution would present.
#337
Oh my, don't tell the TransAM folks that! They swear they are equal systems. It's right in the Vintage TA rules. 27T 4 Cell = 17.5BL 4 Cell = 21.5BL 2S LiPo.
#338
I guess things could appear eqaul since not the battery or motor is being pushed to the limits.
But open the gates up and reduce the min weight some and there will be some differences in performance.
#339
Tech Elite
iTrader: (49)
No , I didn't. I didn't weight either version. I didn't feel the need as the 5K CORE Lipo I was using was only 25 grams lighter than the 4 cell pack. That being the only change (unless the 21.5 and 17.5 are significantly different) I am confident the cars were within 30 grams of each other.
#340
Here are some pics of my new FF07 A123 Chassis. Jari was nice enough to allow me to make a couple for my own personal use. These are not for sale.
They actually need to be re-done. The cell spacing needs to be moved out a bit.
I ran my 2s car at the last club race and with the proper gearing it was about even with the faster 4 cell car.
They actually need to be re-done. The cell spacing needs to be moved out a bit.
I ran my 2s car at the last club race and with the proper gearing it was about even with the faster 4 cell car.
#341
That's pretty cool. Good job.
#342
Tech Adept
@AndrewNicholas: Does this chassis fit a brushless esc? I had many problems fitting a SP LPF with 2s A123.
#343
Here are some pics of my new FF07 A123 Chassis. Jari was nice enough to allow me to make a couple for my own personal use. These are not for sale.
They actually need to be re-done. The cell spacing needs to be moved out a bit.
I ran my 2s car at the last club race and with the proper gearing it was about even with the faster 4 cell car.
They actually need to be re-done. The cell spacing needs to be moved out a bit.
I ran my 2s car at the last club race and with the proper gearing it was about even with the faster 4 cell car.
#344
Yes it does. I am using the Tekin RS Pro.
#345
Tech Master
iTrader: (9)
My 2 cents on the 12th scale and WGT battery issue...
I wouldnt mind running NIMH cells forever personally cuz Im old-school...
But I think the best overall solution would be a somewhat standardized 7.4v hardcase lipo made in brick and saddle configurations that would fit all the current cars....and we run them with high turn brushless motors...
The spec classes might be something like 21.5 or 17.5.....and mod is mod...we would probably run 7.5-10.5 turn motors if I had to guess...
I guess we will see what happens...
I wouldnt mind running NIMH cells forever personally cuz Im old-school...
But I think the best overall solution would be a somewhat standardized 7.4v hardcase lipo made in brick and saddle configurations that would fit all the current cars....and we run them with high turn brushless motors...
The spec classes might be something like 21.5 or 17.5.....and mod is mod...we would probably run 7.5-10.5 turn motors if I had to guess...
I guess we will see what happens...