deepfree_z

http://www.lrp-hpi-challenge.com/ ,
than choose setups/tipps,
after that click "Tips zum Fahrverhalten verschiedener HPI Karosserien"

TimPotter

iTrader: (15)

The body is just another factor in the overall setup of the car. Like all items in your setup, you use the environment to pick out what to change. Temperature, Surface, Traction, Tires, all have bearing on which body performs better.

niznai , for any given setup, run different body's back to back, and you will tell how much different ( or not ) they are. I can guarantee running a R9R back to back with a Mazda 6, you will know.

JR007

I would say until your lap times came within 1/10th to 2/10th's of a second in consistency, and you seldom crashed, the gains of aerodynamics beyond spoiler position would be irrelavent. My 2c

joe of loath

iTrader: (1)

Meh, not sure about that. Maybe 1 sec consistency. I can go faster with a better handling shell, and my consistency is only about 2 seconds.

PizzaDude

ttt

rcko

iTrader: (15)

i know, back in the 90's running flat oval parking lot tracks, the wing made a pretty darn big difference in stabilizing the car along the straights as well as helping to get the rear end planted. Also, the body rear end made a difference. We used to cut those out as well vs, the way touring tends to run them today. On the oval we used to spent quite a lot of time at high speed compared to a circuit so I tend to believe the aero there play more significance vs TC. Now, TC big track were the cars get going pretty darn fast as in 140ft back straights etc, we are pushing high 40 and mod in the 50mph (seen the radar gun readout). Nitro are also pretty fast. At these speeds, specially around sweepers, the aero of the body have to playing an effect. Specially when it comes to rake angle. I know the wings are for sure providing a stabilizing effect.

here is another one, I seen 1.12th scale cars lift the front end at high speed from too much rake... so much so, they loose the steering going into sweeper. I think aero has an effect, but it really depends onthe track speed.

JRXS_chris

Cutting the rear of the shell out increases the amount of air rushing under the shell due to the vacuum created as the car 'punches' a hole through the air. This pulls the whole car down increasing traction. That's why there are rules on how much you cut that section out.

If you look at 8th on-road cars the back end is completely cut out to maximise the traction available.

I did loads of tests for my university dissertation a couple of years ago so if anyone has any questions I'll be happy to answer.

Brian McGreevy

iTrader: (10)

The thing most people don't understand about R/C car aero is this:

The bodies DO in fact, generate downforce. Sure, they don't generate near as much as full scale equivalents, but that's not the point. It's all relative to the weight of the car. For the sake of argument, let's say a 1:1 TC generates 250 lbs of downforce at 100 mph, with a car that weighs around 2500 lbs...so downforce = 10% of it's weight. Now let's look out our 1/10th scale TC's. Average cornering speeds are probably in the neighborhood of 15-20 mph. If a body can produce even 5 oz of downforce, for about a 51 oz car, you have your 10%.

Tire grip is proportional (to a certain upper limit) to the normal force placed on it, either during cornering, acceleration, braking, or a combination of these. I would imagine that R/C TC tires are much more load sensitive than full-size pneumatic race tires because of their relative lack of sidewall or inflation of air. This means that they would require less downforce to generate similar grip increases.

JRXS_chris

following on from the above:

- that's why your car handles rubbish when the wing falls off!

Racer X

iTrader: (2)

Anyone who has ran two different bodies back to back on a car knows that the body does make a big difference. For those who don't believe the body does much, take the rear wing off the car and try to drive 1 lap and you will be a believer.