1/12 forum
|
|||
Tech Champion
iTrader: (44)
1S vs. 4 cell
Just wondering what the consensus is on 1/12th
Has everyone switched to 1S lipo or are there still many who are still using 4 Cell NiMh?
So far the new 1S compatible speed controls have just trickled out on the market. I know the Tekin RS can do it and so can the newly released SXX V2, but what about Novak and any others? I know Novak had the Havoc 1S but that is dated in technology compared to the Tekin and SXX.
Also while I'm on the subject of 1S vs. 4 cell. What about T-bar vs. Link. Is the link style rear end a better handler than the good old T-bar?
Has everyone switched to 1S lipo or are there still many who are still using 4 Cell NiMh?
So far the new 1S compatible speed controls have just trickled out on the market. I know the Tekin RS can do it and so can the newly released SXX V2, but what about Novak and any others? I know Novak had the Havoc 1S but that is dated in technology compared to the Tekin and SXX.
Also while I'm on the subject of 1S vs. 4 cell. What about T-bar vs. Link. Is the link style rear end a better handler than the good old T-bar?
Tech Champion
iTrader: (34)
Just wondering what the consensus is on 1/12th
Has everyone switched to 1S lipo or are there still many who are still using 4 Cell NiMh?
So far the new 1S compatible speed controls have just trickled out on the market. I know the Tekin RS can do it and so can the newly released SXX V2, but what about Novak and any others? I know Novak had the Havoc 1S but that is dated in technology compared to the Tekin and SXX.
Also while I'm on the subject of 1S vs. 4 cell. What about T-bar vs. Link. Is the link style rear end a better handler than the good old T-bar?
Has everyone switched to 1S lipo or are there still many who are still using 4 Cell NiMh?
So far the new 1S compatible speed controls have just trickled out on the market. I know the Tekin RS can do it and so can the newly released SXX V2, but what about Novak and any others? I know Novak had the Havoc 1S but that is dated in technology compared to the Tekin and SXX.
Also while I'm on the subject of 1S vs. 4 cell. What about T-bar vs. Link. Is the link style rear end a better handler than the good old T-bar?
There are many speedos that work with 1S, perhaps a year ago they were "trickling" in, but the floodgates have opened on the 1S / Link racing now.
At our local races there are still a few round cell racers, some use them for a voltage advantage in the Cirtix Spec class, while others have t-bar cars, and older equipment that work best with that type of cell.
search these speedos for more info
The LRP SXXv2 is more for mod type racing.
SXXSS is a pure bred spec boost speedo.
Tekin RS
AEBD
Novak Kinetic
Speed Passion
Mamba
Hi,
I've raced electric off-road from 1988 to 1999, had an eleven year break from RC and I'm now getting into 12th scale. I went to a local club and recently ordered some stuff . I went for a Team Associated 12R5.1.
So, I'm totally green when it comes to 1:12 and current technologies. I built the car, which was fun, apart from sanding/glueing/sanding CF parts. That takes about as much time as actually building the car, if not more .
However during building I noticed some things, I've got some questions:
- The pivot brace is under an angle when adjusting it for for free lower rear pod plate movement.One side is sitting to the front, while the other is sitting to the rear. I guess this is normal/intended.
My car is the same as this
- One of the holes in the left & right rear pod links binds slightly without even having inserted a M2 screw. Its not bad, but its not optimal either. It seems to be mold related, since its the same hole that slightly binds for both links. What is usually done to fix this? Polish the ball? This would remove the coating, wouldn't it? Enlarge the hole somehow?
Try squeezing the plastic part with pliers around the ball to indent it around the ball and free it up slightly
- The pivot balls in the lower front suspension arms bind very badly, they don't move freely at all. Is this normal? Should I fix it somehow? Polish the ball? Enlarge the hole somehow?
Same as last post squeeze the plastic of the arm around the ball to free it up.
- With default settings, the pod is sitting upwards. With the wheels from the ground, shouldn't the rear pod rest downwards (some droop), so one could adjust the center shock preload to make the pod aligned to the chassis under static load (car resting on its wheels with full mass)? I used the (default) center shock droop spacer. The center shock aluminum rod end is all the way onto the shaft. Shouldn't it be? Should I unscrew the ball cup a few millimeters? Or shorten the droop spacer in the shock? How much droop should I aim for?
Check you droop spacer is trimmed to the correct length and trim to suit, i run 1mm of pod droop on my car
- Which Ackermann servo spacers should I use by default? ( Ko Propo #30048 PDS-951ICS ICS 6.0V Digital FET Servo ). At the moment I used one thick spacer per side. In a top view with steering centered, the turnbuckles are sitting colinear.
my steering links run inline with each other
- How am I supposed to use the tiny receiver antenna with the solid antenna mast? Use shrink wrap around the mast with the antenna inside?
just try and run it up the mast as far as possible without touching any other electrics
- Do people position LiPo's to the front or rear? My assumption with LiPo's being lighter than sub-C cells, people would move LiPo's to the front to retain some front end weight. However, pics from the recent worlds show this:
Marc Rheinard: LiPo to the front
Ronald Völker: LiPo to the back
Juho Levanen: LiPo to the front, the ESC is turned 90 degrees to make room for the LiPo
I have used my car since last winter and it was cells at the time so the lipo guys may be able to help you with this
Don't know if the pics were I got this info from were taken during similar track conditions. Or maybe it just comes down to driver preference. I guess I'll install electronics in a way so I can strap the LiPo either to the front or rear (or somewhere in between). Is it true positioning the LiPo to the back actually gives more steering? Is moving it to the front used to reduce grip rolls?
- Just have to install electronics now. I must say, its pretty tempting to trim all receiver channel wires to custom length as well. Not sure if that would void the warranty of the ESC/servo/transponder. Its a bit of a handfull to fit the standard length receiver wires into the car, it doesn't look very tidy either.
Most people either shorten the wires or just fold them up and black heatshrink them so they are slightly neater
- Oh, how many guys replace some of the not-so-stressed steel screws with blue anodized aluminum/titanium ones? Seems a bit iffy to me, but i guess its doable for some screws. On the other hand, better to snap a screw than rip a chassis plate on heavy impact.
Thanks in advance to anyone taking the effort to answer these questions!
( Sorry, I can't link URL's yet for pictures: "You are only allowed to post URLs to other sites after you have made a certain number of posts. You have not reached that limit yet." )
I've raced electric off-road from 1988 to 1999, had an eleven year break from RC and I'm now getting into 12th scale. I went to a local club and recently ordered some stuff . I went for a Team Associated 12R5.1.
- Team Associated #4019 RC12R5.1 Factory Team
- Protoform #1611-21 AMR-12 Light Weight Clear Body
- LRP #50682 Vector X12 Brushless Modified - 5.5t
- LRP #80905 SXX Competition Version 2 Brushless ESC
- Ko Propo #30048 PDS-951ICS ICS 6.0V Digital FET Servo
- MYLAPS RC4 Hybrid Transponder
- 4x LRP #79877 LiPo Competition Car Line 1S Hardcase 5400 - 50C - 3.7V
- Ko Propo #80400 EX-10 Eurus 2.4GHz SS (Tx/Rx with setting module)
- Graupner #6444 ULTRA DUO PLUS 50
So, I'm totally green when it comes to 1:12 and current technologies. I built the car, which was fun, apart from sanding/glueing/sanding CF parts. That takes about as much time as actually building the car, if not more .
However during building I noticed some things, I've got some questions:
- The pivot brace is under an angle when adjusting it for for free lower rear pod plate movement.One side is sitting to the front, while the other is sitting to the rear. I guess this is normal/intended.
My car is the same as this
- One of the holes in the left & right rear pod links binds slightly without even having inserted a M2 screw. Its not bad, but its not optimal either. It seems to be mold related, since its the same hole that slightly binds for both links. What is usually done to fix this? Polish the ball? This would remove the coating, wouldn't it? Enlarge the hole somehow?
Try squeezing the plastic part with pliers around the ball to indent it around the ball and free it up slightly
- The pivot balls in the lower front suspension arms bind very badly, they don't move freely at all. Is this normal? Should I fix it somehow? Polish the ball? Enlarge the hole somehow?
Same as last post squeeze the plastic of the arm around the ball to free it up.
- With default settings, the pod is sitting upwards. With the wheels from the ground, shouldn't the rear pod rest downwards (some droop), so one could adjust the center shock preload to make the pod aligned to the chassis under static load (car resting on its wheels with full mass)? I used the (default) center shock droop spacer. The center shock aluminum rod end is all the way onto the shaft. Shouldn't it be? Should I unscrew the ball cup a few millimeters? Or shorten the droop spacer in the shock? How much droop should I aim for?
Check you droop spacer is trimmed to the correct length and trim to suit, i run 1mm of pod droop on my car
- Which Ackermann servo spacers should I use by default? ( Ko Propo #30048 PDS-951ICS ICS 6.0V Digital FET Servo ). At the moment I used one thick spacer per side. In a top view with steering centered, the turnbuckles are sitting colinear.
my steering links run inline with each other
- How am I supposed to use the tiny receiver antenna with the solid antenna mast? Use shrink wrap around the mast with the antenna inside?
just try and run it up the mast as far as possible without touching any other electrics
- Do people position LiPo's to the front or rear? My assumption with LiPo's being lighter than sub-C cells, people would move LiPo's to the front to retain some front end weight. However, pics from the recent worlds show this:
Marc Rheinard: LiPo to the front
Ronald Völker: LiPo to the back
Juho Levanen: LiPo to the front, the ESC is turned 90 degrees to make room for the LiPo
I have used my car since last winter and it was cells at the time so the lipo guys may be able to help you with this
Don't know if the pics were I got this info from were taken during similar track conditions. Or maybe it just comes down to driver preference. I guess I'll install electronics in a way so I can strap the LiPo either to the front or rear (or somewhere in between). Is it true positioning the LiPo to the back actually gives more steering? Is moving it to the front used to reduce grip rolls?
- Just have to install electronics now. I must say, its pretty tempting to trim all receiver channel wires to custom length as well. Not sure if that would void the warranty of the ESC/servo/transponder. Its a bit of a handfull to fit the standard length receiver wires into the car, it doesn't look very tidy either.
Most people either shorten the wires or just fold them up and black heatshrink them so they are slightly neater
- Oh, how many guys replace some of the not-so-stressed steel screws with blue anodized aluminum/titanium ones? Seems a bit iffy to me, but i guess its doable for some screws. On the other hand, better to snap a screw than rip a chassis plate on heavy impact.
Thanks in advance to anyone taking the effort to answer these questions!
( Sorry, I can't link URL's yet for pictures: "You are only allowed to post URLs to other sites after you have made a certain number of posts. You have not reached that limit yet." )
Tech Champion
Hi,
- Do people position LiPo's to the front or rear? My assumption with LiPo's being lighter than sub-C cells, people would move LiPo's to the front to retain some front end weight. However, pics from the recent worlds show this:
Marc Rheinard: LiPo to the front
Ronald Völker: LiPo to the back
Juho Levanen: LiPo to the front, the ESC is turned 90 degrees to make room for the LiPo
Don't know if the pics were I got this info from were taken during similar track conditions. Or maybe it just comes down to driver preference. I guess I'll install electronics in a way so I can strap the LiPo either to the front or rear (or somewhere in between). Is it true positioning the LiPo to the back actually gives more steering? Is moving it to the front used to reduce grip rolls?
- Do people position LiPo's to the front or rear? My assumption with LiPo's being lighter than sub-C cells, people would move LiPo's to the front to retain some front end weight. However, pics from the recent worlds show this:
Marc Rheinard: LiPo to the front
Ronald Völker: LiPo to the back
Juho Levanen: LiPo to the front, the ESC is turned 90 degrees to make room for the LiPo
Don't know if the pics were I got this info from were taken during similar track conditions. Or maybe it just comes down to driver preference. I guess I'll install electronics in a way so I can strap the LiPo either to the front or rear (or somewhere in between). Is it true positioning the LiPo to the back actually gives more steering? Is moving it to the front used to reduce grip rolls?
It's an adjustment just like anything else. Forward, more stable and less likely to traction roll. Back, more steering, more aggressive. I know it sounds backward but that's the way it is and there is good physics behind the reason. The only thing switching to lighter lipos really did is reduce how dramatic an adjustment it is.
Tech Champion
iTrader: (1)
I guess it depends on what you prefer the feel of. If the pro's all run different settings then that alone tells you its more a preference than outright pace. I have tried forward and backward and much prefer the feel of the car with it forward. I found no real difference in lap times (possibly a tenth) but the car is much better over a run with it forward. In fact I have found concentracting all the weight towards the center of the car means where ever I go I drop the car on the track and turn good times from the get go before I bother doing any tuning. I can only see this as a good thing.
When you add vertical load to a tire, it gains traction. But if you put them both on a graph, you will see that the traction goes up less than the load is going up. For example, take a tire with a 1 pound vertical load on it, let's say it can take 1 pound of lateral load before it slides. Now double the vertical load to 2 pounds. Does it now take 2 pounds of lateral load to make it slide? No, it will slide at a lesser load, let's say 1.8 pounds.
Secondly, if you move static weight forward in the car, you are putting more vertical load on the front tires but you are also moving the center of gravity forward. Obviously I am talking about the fore/aft position of the cg, not the height. The cg is the point on the car where centrifugal force pushes on it to try and push the car towards the outside of the corner. Let's see an example of how this might affect things.
Imagine a 1 pound car. It has the exact same tires all the way around and its weight distribution is exactly even, 1/4 pound of weight on each tire. Its fore/aft cg position will be right in the middle of the car between the tires. Now let's say skid pad tests show this car can take a 1 pound lateral load before skidding, meaning it can corner at 1g and it's perfectly balanced handling wise so when it skids, it's a four wheel drift out of the circle, not a spin out or an understeer out of the circle. If you doubled the car's weight to 2 pounds, the tires will gain more traction but not as much as the weight will increase the lateral load so the car will now skid with a 1.8 pound lateral load which is LESS than 1g with a two pound car.
Now let's go back to the one pound car but let's move some component forward so that the front tires now have more weight on them. This would initially seem to increase front traction so now this car will spin out when it skids instead of a nice, balanced, 4 wheel drift right? No, that's wrong. Remember, traction goes up more slowly than the vertical load does. So what happens is that the now more lightly loaded rear tires have lost less traction than the fronts have gained. But this alone is only part of the story since we are still seeing a loss of rear traction and a gain in front, even if it isn't an even trade.
That's where fore/aft cg location comes in. Imagine the original, balanced car is stationary on the skid pad and you are in the middle of the skid pad with a pool cue to use to try and push the car from the side out of the circle. The end of the pool cue is placed right on the cg (middle of the car) and the tires and load are the same so when you push on the cue, the car just slides all four tires. Now move the weight forward. The cg moves forward so you have to move the spot on the car that you push with the cue forward. This means you are now pushing harder on the front tires than on the rear. This would be balanced out by the increase in front traction and the decrease in rear traction resulting in another perfect, four wheel slide except that as I said before, the rears have lost less traction than the fronts gained. So the front tires are going to slide first. The car will now understeer.
I hope that makes sense. I am not the best at clearly explaining complex concepts of vehicle dynamics but I have studied it extensively and this is the basic consensus of ALL well informed engineers on the subject. This is why nose heavy front engined cars fight understeer issues while tail heavy rear engined cars like 911s fight with oversteer.
Also, this subject can get even more confusing due to another effect. As I described above, moving the weight to the rear should make the car oversteer but there is a situation where this could be backward. Moving the weight back will make the car looser in a steady state corner but with a rear wheel drive car, the increase in rear weight could reduce wheel spin under power, improving rear traction. This is why offroad dirt cars have such a high rear weight distribution. So in this situation, moving the weight to the rear could result in more steering off power but less on power. Especially when powering off of a slow corner, but might have even MORE on power steering exiting a fast corner.
Last edited by wingracer; 09-19-2010 at 08:06 AM.
Tech Champion
iTrader: (261)
Wow.
Michael, you are NEVER to say a word about one of my posts again.
You either Doug.
Michael, you are NEVER to say a word about one of my posts again.
You either Doug.
Tech Addict
iTrader: (2)
Wingracer, that was a great post. Very informative, thanks!
Let the battery thing (1S, 2S, 4cell) aside just from the point of handling, what do you think is the better car t-bar car or link-car and why?
Nope. Let me see if I can explain it. There are two reasons for the effect.
When you add vertical load to a tire, it gains traction. But if you put them both on a graph, you will see that the traction goes up less than the load is going up. For example, take a tire with a 1 pound vertical load on it let's say it can take 1 pound of lateral load before it slides. Now double the vertical load to 2 pounds. Does it now take 2 pounds of lateral load to make it slide? No, it will slide at a lesser load, let's say 1.8 pounds.
Secondly, if you move static weight forward in the car, you are putting more vertical load on the front tires but you are also moving the center of gravity forward. Obviously I am talking about the fore/aft position of the cg, not the height. The cg is the point on the car where centrifugal force pushes on to try an push the car towards the outside of the corner. Let's see an example of how this might affect things.
Imagine a 1 pound car. It has the exact same tires all the way around and its weight distribution is exactly even, 1/4 pound of weight on each tire. Its fore/aft cg position will be right in the middle of the car between the tires. Now let's say skid pad tests show this car take a 1 pound lateral load before skidding, meaning it can corner at 1g and its perfectly balanced handling wise so when it skids, it's a four wheel drift out of the circle, not a spin out or an understeer out of the circle. If you doubled the car's weight to 2 pounds, the tires will gain more traction but not as much as the weight will increase the lateral load so the car will now skid with a 1.8 pound lateral load which is LESS than 1g with a two pound car.
Now let's go back to the one pound car but let's move some component forward so that the front tires now have more weight on them. This would initially seem to increase front traction so now this car will spin out when it skids instead of a nice, balanced, 4 wheel drift right? No, that's wrong. Remember, traction goes up more slowly than the vertical load does. So what happens is that the now more lightly loaded rear tires have lost less traction than the fronts have gained. But this alone is only part of the story since we are still seeing a loss of rear traction and a gain in front, even if it isn't an even trade.
That's where fore/aft cg location comes in. Imagine the original, balanced car is stationary on the skid pad and you are in the middle of the skid pad with a pool cue to use to try and push the car from the side out of the circle. The end of the pool cue is placed right on the cg (middle of the car) and the tires and load are the same so when you push on the cue, the car just slides all four tires. Now move the weight forward. The cg moves forward so you have to move the spot on the car that you push with the cue forward. This means you are now pushing harder on the front tires than on the rear. This would be balanced out by the increase in front traction and the decrease in rear traction resulting in another perfect, four wheel slide except that as I said before, the rears have lost less traction than the fronts gained. So the front tires are going to slide first. The car will now understeer.
I hope that makes sense. I am not the best at clearly explaining complex concepts of vehicle dynamics but I have studied it extensively and this is the basic consensus of ALL well informed engineers on the subject. This is why nose heavy front engined cars fight understeer issues while tail heavy rear engined cars like 911s fight with oversteer.
Also, this subject can get even more confusing due to another effect. As I described above, moving the weight to the rear should make the car oversteer but there is a situation where this could be backward. Moving the weight back will make the car looser in a steady state corner but with a rear wheel drive car, the increase in rear weight could reduce wheel spin under power, improving rear traction. This is why offroad dirt cars have such a high rear weight distribution. So in this situation, moving the weight to the rear could result in more steering off power but less on power. Especially when powering off of a slow corner, but might have even MORE on power steering exiting a fast corner.
When you add vertical load to a tire, it gains traction. But if you put them both on a graph, you will see that the traction goes up less than the load is going up. For example, take a tire with a 1 pound vertical load on it let's say it can take 1 pound of lateral load before it slides. Now double the vertical load to 2 pounds. Does it now take 2 pounds of lateral load to make it slide? No, it will slide at a lesser load, let's say 1.8 pounds.
Secondly, if you move static weight forward in the car, you are putting more vertical load on the front tires but you are also moving the center of gravity forward. Obviously I am talking about the fore/aft position of the cg, not the height. The cg is the point on the car where centrifugal force pushes on to try an push the car towards the outside of the corner. Let's see an example of how this might affect things.
Imagine a 1 pound car. It has the exact same tires all the way around and its weight distribution is exactly even, 1/4 pound of weight on each tire. Its fore/aft cg position will be right in the middle of the car between the tires. Now let's say skid pad tests show this car take a 1 pound lateral load before skidding, meaning it can corner at 1g and its perfectly balanced handling wise so when it skids, it's a four wheel drift out of the circle, not a spin out or an understeer out of the circle. If you doubled the car's weight to 2 pounds, the tires will gain more traction but not as much as the weight will increase the lateral load so the car will now skid with a 1.8 pound lateral load which is LESS than 1g with a two pound car.
Now let's go back to the one pound car but let's move some component forward so that the front tires now have more weight on them. This would initially seem to increase front traction so now this car will spin out when it skids instead of a nice, balanced, 4 wheel drift right? No, that's wrong. Remember, traction goes up more slowly than the vertical load does. So what happens is that the now more lightly loaded rear tires have lost less traction than the fronts have gained. But this alone is only part of the story since we are still seeing a loss of rear traction and a gain in front, even if it isn't an even trade.
That's where fore/aft cg location comes in. Imagine the original, balanced car is stationary on the skid pad and you are in the middle of the skid pad with a pool cue to use to try and push the car from the side out of the circle. The end of the pool cue is placed right on the cg (middle of the car) and the tires and load are the same so when you push on the cue, the car just slides all four tires. Now move the weight forward. The cg moves forward so you have to move the spot on the car that you push with the cue forward. This means you are now pushing harder on the front tires than on the rear. This would be balanced out by the increase in front traction and the decrease in rear traction resulting in another perfect, four wheel slide except that as I said before, the rears have lost less traction than the fronts gained. So the front tires are going to slide first. The car will now understeer.
I hope that makes sense. I am not the best at clearly explaining complex concepts of vehicle dynamics but I have studied it extensively and this is the basic consensus of ALL well informed engineers on the subject. This is why nose heavy front engined cars fight understeer issues while tail heavy rear engined cars like 911s fight with oversteer.
Also, this subject can get even more confusing due to another effect. As I described above, moving the weight to the rear should make the car oversteer but there is a situation where this could be backward. Moving the weight back will make the car looser in a steady state corner but with a rear wheel drive car, the increase in rear weight could reduce wheel spin under power, improving rear traction. This is why offroad dirt cars have such a high rear weight distribution. So in this situation, moving the weight to the rear could result in more steering off power but less on power. Especially when powering off of a slow corner, but might have even MORE on power steering exiting a fast corner.
During this period they would have a car design with the 6 cell NiCd on the center line of the car, but pretty far to the back. Also the motor (behind the rear axle), pretty far to the front. So basically all its mass was focussed at one point, while the position of its CG would be similar to other cars. The car would have fair amounts of steering both off and on throttle, but generally worse than average traction out of corners. As in, when it started to slide, it was an utter mess. (Talking low grip hard packed clay tracks, not astroturf or grass.)
There used to be other 2WD cars around with the 6 cell NiCd way to the front, the motor way to the back. About the same CG, but the mass spread out way more, causing in way more predictable slides when on the edge of grip.
( Of course nowadays 2WD is going yet another direction with the motor in front of the axle, using a different principle. )
Last edited by kjoer; 09-19-2010 at 05:47 AM.