i've owned a Pro4, for bout 2 weeks ...lol
the shaft car had better acceleration an great handling.
but comming from a belt drive it felt harder to drive ...(im comparing out of box setups)
after tryin both ...i found that the belt drive suited me more ..
this is different 4 everyone ..so
Noise has no correlation w/ friction. Belt drive cars are a combonation of soft plastic belts on delrin diff gears. Shaft drivetrains are composite plastic on delrin diff gears.
Starting friction is higher on shaft drive but rolling friction is lower. Starting friction is /U. Ff=Fp. The Force natural is slightly lower due to the lessened rolling resistance.
Oh yeah, /U is the resistance to motion and unbalancing an equillibrium. Ff is the force of friction. Fp is the force parallel. Fn is the force natural.
Originally posted by Pro4Capece Yeah I like my pro 4, but I equally like belt drive cars. I just took offense when you said they weren't that competitive. No hard feelings.
None taken. I never said shafts weren't competitive though. I was speaking of major races here in the U.S.... not abroad. I forgot that HPI won the Roar nats. ...my bad. All I remember was that the Tamiya 415, Xray FK, & Losi XXX-SG+ won most here in the U.S. from mag. coverage.
Bottom line is any car can win on any day. So in the end it's all about preference.
HPI is setting the pace for touring cars. I predict that HPI and Losi go at it all winter long. HPI w/ their super tight chassis layout and Losi has those really short arms. It's going to be tough for the TC4, or the Evo 4 the match their carpet breed designs.
Most of the Major manufaturers went to a shaft car, after they seen the great sales from the tc3.
hpi
belt to shaft
yokomo
shaft
Tamiya
they have both
asc
shaft
I think shaft cars are probably more easier and possibly les maintence.
My personel opinion it seems like basic physics,
Belts pull
shafts twist
In order to get the twisting going forward, you have to dial out the tork steer so to speak. But the technology is so much improved since the first tamiya shaft, that it's probably not that bad of a problem.
Still though, belts make more sense to me, I'll stay with belt.
Originally posted by dasupacat The shafties just got belted at the worlds. LOL. From the coverage I've seen through the mags. and net. Belted cars have had more major wins than the shafties this year. As a matter of fact, can't remember the last time a shaft car won a major event here in the U.S.
Just the drivetrain doesn't determine a win. What determines a successfull win is suspension, drivetrain, power, tires, a setup of all 4 and the driver.
Again the difference in the resultant is minimal. For a belt driven car there must be belt tensioners. This reduces the leverage a belt can put on the diff.
The cosine times (angle of tension to the angle of the belt)= the Force Natural(real power at the wheels)
Fn=cos(tension angle)
Untill someone makes a belt that doesn't require tensioners or swing arms, belts will have less acceleration and less top speed. Torque steer is relative to the chassis tweak, not the rotation of the shaft and gears.
Does anyone understand what I am saying, or is this a lost cause?
well actually. if you replace your belts before they stretch out you dont need any tensioners. and have you seen how the differentials are mounted on say a xray? or like the rear diffs of a hpi pro2. the xray's front and rear diffs move fore and aft ever so slightly using these clever little indents to hold a "cam" shaped diff bearing holder. so currently i run my xray with no belt tensioner so to speak. it tensions it, but without anything extra like the front belt in my hpi. the rs4 uses the same concept for the rear diff bearing mounts so it stays tight without a tensioner. well, i dunno which came first but eh.
and yeah, my belt isnt skipping. no problems there. so no a belt tensioner is not required.
so, assuming (big assuming) that the drivetrains of a shaft and belt are the same, the belt would accelerate faster because it has less mass to rotate.
That's correct. Does your belt have any lateral or vertical movement when you accelerate? If so, that is where some of the energy is being exerted. Fv (force vertical). If your XRay is truly flush and the belt doesn't bow, then you have the perfect drivetrain.
honestly IT DOES NOT MATTER!!! yes the "shafties got belted at the worlds and at the race of champions" but you have to remember!!! THREE letters!!! P....R...O!! these are pro drivers top caliber and the best in the world. not to mention they gel all the best batts, motors, prototype $hit. IMO you should keep an eye at the expert level. these are more of the regular joe's. which cars dominate and which brands get smoked.
basically this is a question of what is more suited to you driving style.
SHAFT :
cons
-torque steer
-chassis tweek (if you tweek your car on a board its energy at rest. when you go on the throttle you create an energy what makes the car transfer weight left to right due to action of the motor)
pros
-supa free drivetrain = great acceleration
-not as hard to maintain esp if it has a sealed drivetrain
belts
cons
-faster wear (belt)
-less acceleration
pros
-less wear on other drivetrain parts (outdrives, cvd, etc.)
-supa smooth acceleration
-no torque steer = more consistent laps
bottomline_____________________________
shaft cars are great for stock racing. get the advantage over the other cars using a supa free drivetrain and torque steer isnt much noticable.
belt cars are nice for mod racing . get a supa smooth/linear acceleration and better handling cause you loose torque steer which is quite noticale on shaft cars ESP> on mod racing.
Originally posted by Pro4Capece Again the difference in the resultant is minimal. For a belt driven car there must be belt tensioners. This reduces the leverage a belt can put on the diff.
The cosine times (angle of tension to the angle of the belt)= the Force Natural(real power at the wheels)
Fn=cos(tension angle)
Untill someone makes a belt that doesn't require tensioners or swing arms, belts will have less acceleration and less top speed. Torque steer is relative to the chassis tweak, not the rotation of the shaft and gears.
Does anyone understand what I am saying, or is this a lost cause?
I'm sure there are a few people who understand what you're saying (i'm one ), but you appear to be so one-sided in your assesment that you are only stating facts that prove your point, yet there are other factors to consider.
Now I am not going to debate which is better, but I will add some facts that have been mis interperated, missed altogether, or just plain stated wrong.
Fact: Many belt cars don't use or need tensioners.
Fact: Ball bearings, as efficient as they are, still create friction, and shaft drive cars have more bearings.
Fact: Shaft drive's do suffer from torque steer, even though it is very minimal, and it is a result of an off-set longitudinally mounted motor.
Fact: Noise DOES equal friction! When two surfaces of differing hardness/strength/material are rubbing together, they create less friction than two surfaces of the same material. Think about that when looking at the drive train of a belt or shaft car.
Fact: friction losses in a shaft drive car are at their maximum at full speed, friction losses in a belt drive car are at their minimum at full speed, and vice versa under acceleration.
It's all well and good to try and blind people with science to "win" an argument, but this doesn't make your statement any more believable when they are biased.
Bottom line: any advantage gained in one area by one type of drivetrain is lost in another area.
Result= belt and shaft are equal
Well said Bender.
I just happen to look through one of my XRC mags. Found that during the Roar paved champs. Only 1 out of 10 cars in BOTH the stock & 19t A-main was a shaft car (TC3). So much for efficiency. Neither won by the way.....
Just for those who think shafts will eliminate torque steer.....
Grip is related to weight on the tyres.....
Shaft drive cars roll left/right when you acc/brake transfering weight to one side of the car.
When you have more grip on one side of your car the car will turn under braking/acc .
Ultimatly the driver dictates the speed of the car but after all this argument I'm sure you realise that the belts have more grip, and the shafts have more top end speed. Why keep arguing here when you can have more fun proving it at the track.
__________________
FlyingFoxRC Team Twister Hobbies
Fantom Team Wave
), but you appear to be so one-sided in your assesment that you are only stating facts that prove your point, yet there are other factors to consider.
Neither won by the way.....
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