Two thoughts I would like opinions on guys:

1. I have been seeing the Nextel cup cars run with "yaw" in their cars. They say this helps them getting through the corner or something like that. Would mounting a body on a 1/10 scale car promote this same benefit?


2. Would a cut out at the base of a 1/10 scale windshield with a duct attached that feeds air directly to the motor really help to cool it? Would this adversely effect the cars other handling / aerodynamics? Would this be ROAR legal?

Thanks,
Ron

Two thoughts I would like opinions on guys:

1. I have been seeing the Nextel cup cars run with "yaw" in their cars. They say this helps them getting through the corner or something like that. Would mounting a body on a 1/10 scale car promote this same benefit?


2. Would a cut out at the base of a 1/10 scale windshield with a duct attached that feeds air directly to the motor really help to cool it? Would this adversely effect the cars other handling / aerodynamics? Would this be ROAR legal?

Thanks,
Ron

1. This is effectively molded into the newer Protoform bodies already. Yes, it helps.

2. I think there may be a rule that the windshield must be intact for ROAR.

I have noticeable results when I push the right side door panel outward so it gets angled, and also push out the LF fender in front of the tire.

I believe the cutting of the windshield would not be allowed, but you could I believe cut the grille area and duct from there...or come up with a scoop duct on the sides of the chassis to divert airflow toward the motor.

Didn't Dahm's have a stock car body with a duct kit to cool the motor a few years ago?

aerodynamically i'm sure it's helpful but it's one of the tenths of tenths that your trying to compound to go faster! I think more than the aero advantage, there is the offset that happens from RF to RR that makes the car enter harder and turn thru the center better. It causes the RF to be stabbed by more of the car's weight at the entry of the turn, forcing it to grip.

We used to cut a side scoop in front of the left rear to duct air over the speedo before the GTB came out. The old SS ran hot. As far as the windshield part nobody cares about ROAR, they are no longer around right?? Local tracks would rule on that anyway.

Two thoughts I would like opinions on guys:

1. I have been seeing the Nextel cup cars run with "yaw" in their cars. They say this helps them getting through the corner or something like that. Would mounting a body on a 1/10 scale car promote this same benefit?


2. Would a cut out at the base of a 1/10 scale windshield with a duct attached that feeds air directly to the motor really help to cool it? Would this adversely effect the cars other handling / aerodynamics? Would this be ROAR legal?

Thanks,
Ron


actually on the COT they can only twist the body on the chassis like 1/4 or 1/2 inch. they can run rear steer but only a little.

what you are seeing on TV is. the guys are now follow me here. they are actually angling the endplates of the rear end housing. so what it actually does is turn the rear tires.

Didn't Dahm's have a stock car body with a duct kit to cool the motor a few years ago?

S&K made bodies with a tunnel through them for cooling.

Didn't Dahm's have a stock car body with a duct kit to cool the motor a few years ago?

S & K made some of these bodies, some for gearbox oval trucks, an onroad pan car body(wide 10L) and I think a nascar body. I still have a few of the truck & onroad bodies new in package stashed away. They had an opening in the windshield and a duct to the motor.

Two thoughts I would like opinions on guys:

1. I have been seeing the Nextel cup cars run with "yaw" in their cars. They say this helps them getting through the corner or something like that. Would mounting a body on a 1/10 scale car promote this same benefit?


2. Would a cut out at the base of a 1/10 scale windshield with a duct attached that feeds air directly to the motor really help to cool it? Would this adversely effect the cars other handling / aerodynamics? Would this be ROAR legal?

Thanks,
Ron

On question one pmsimkins hit the nail on the head, the new Protoform bodies have it built in aerodynamically. The same mechanical effect can be achieved with rear steer.

With question 2, one thing to think about is how they try to run as much tape on the grills as possible, and tape them completely off to qualify, all for downforce. Since I race nitro I've thought a lot about openings for cooling, and all of us nitro racers try to keep the frontal area (both the windshield and the grills) intact for downforce, and usually have cooling openings in the left side windows, and that seems to have minimal aerodynamic side effects. We don't run a duct because we have a huge cooling head, not much different than the heat sink on a brushless motor. But just remember that the most aerodynamic body is one without any holes whatsoever, so I don't know if it would help an electric motor enough to warrant cutting up the body.

This is an interesting thread.

what you are seeing on TV is. the guys are now follow me here. they are actually angling the endplates of the rear end housing. so what it actually does is turn the rear tires. Kinda like rear steer?

A car with the rear cut out actually get's pretty good air flow. I agree with Sam though, less holes = more down force. Most of the time on my .09 nitro car I only run a dime size hole in the left window for refueling and I don't have any cooling problems with my engine, the .12 is another story especially when required to run the stock red head.

Kinda like rear steer?


yes like rear steer except instead of turning the axle they are just actually turning the ends

Two thoughts I would like opinions on guys:

1. I have been seeing the Nextel cup cars run with "yaw" in their cars. They say this helps them getting through the corner or something like that. Would mounting a body on a 1/10 scale car promote this same benefit?
Thanks,
Ron

I would think that in stock type racing, you would want to keep the
frontal area as low as you could get it. If you were to mount your
body with the same degree of skew that the cup cars 'were' running,
you would be increasing the size of the hole in the air
you were cutting through.
They (NASCAR) did put a limit on it,
however some of the cars still look ridiculous
crabbing down the straights as they do... (imo)

Downforce usually isn't an issue with stock racing.
Often the issue is too much.
Lower coefficient of drag is important always..

With the seventy billion adjustments that you can make to an r/c car,
that you cannot with a COT car, I'd work on those first.
It's still a matter of efficiency.

Your mileage may vary, of course.
It's just my opinion. :thumbsup:

you notice it more the longer the strighta way is
know in tractor trailer driving as off tracking

I would think that in stock type racing, you would want to keep the
frontal area as low as you could get it. If you were to mount your
body with the same degree of skew that the cup cars 'were' running,
you would be increasing the size of the hole in the air
you were cutting through.
They (NASCAR) did put a limit on it,
however some of the cars still look ridiculous
crabbing down the straights as they do... (imo)

Downforce usually isn't an issue with stock racing.
Often the issue is too much.
Lower coefficient of drag is important always..

With the seventy billion adjustments that you can make to an r/c car,
that you cannot with a COT car, I'd work on those first.
It's still a matter of efficiency.

Your mileage may vary, of course.
It's just my opinion. :thumbsup:


again there is only like a 1/4- 1/2 inch of yaw in the bodies of the COT what you are seeing on tv is what they did by maxing out there rear steer and adding the angle to the rear tires

again there is only like a 1/4- 1/2 inch of yaw in the bodies of the COT what you are seeing on tv is what they did by maxing out there rear steer and adding the angle to the rear tires

Yaw is not measured in inches, it is measured in degrees...
It also can't be measured at rest.
It matters not how much the body is mounted crooked.
You are right the total crab we see,
is a combination of more than one thing,
but the car has more 'yaw angle' because of all of them, not just
the body, not just the axle plates, and not a static skew of the axle,
to change the wheelbase...

When a vehicle is 'aimed' at a different angle, than the direction of
travel, it is in 'yaw'.

They still look stupid...:rolleyes:

I believe what Dave meant is that NASCAR allows less than 1/4-1/2 inch variance with the template on most body areas of the COT car and the body must be mounted square to the center line of the chassis. The physical rear steer in relation to the rear axle mounting points has always been limited in NASCAR so some of the teams started getting around that by using wedge shaped shims at the hub/housing flange to get more rearsteer in the cars. NASCAR finaly decided to put an end to that. Thank You NASCAR.
Down here in Florida I,ve always heard it refered to as " Dog Tracking " someone from the New England area must of come up with the "crabbing" thing.

At Pocono ALL the cars looked like they had too much YAW'N in them...at least they made ME YAWN~

I do not like the way NASCAR is keeping everyone in a BOX. Well not such a small box. The duh-rection they are going it might as well be IROC. Just draw 43 names out of a hat on Wednesday and tell the guys to come race. Then NASCAR can just sell the space on cars for advertising to the highest bidders.

IMHO, the teams are being stifled. This is RACING and all is not fair, let em WORK on the car and let them race.

I do not like the way NASCAR is keeping everyone in a BOX.
IMHO, the teams are being stifled.
...let em WORK on the car and let them race.

I don't get this reasoning.
The more specific the rule structure is,
the HARDER the teams have to work to gain an edge.
Perfect case in point, is the off-tracking of the cars..
Coil binding.
Bump stops.
Cambered rears.
Giant sway bars.
The list is endless.

They have to be much more clever than ever before.
NASCAR doesn't require the cars to be 100% equal.
They still have plenty of adjustments to make, and there are areas
where some have found things that others haven't.
Believe me, there are things being done that are outside the box..

If you just let them go wild,
they will still all have the same thing in time,
just like now. They will just all be a bit faster.
Not much different than r/c.
A new battery/motor/part comes out,
and a few guys are fast until everyone gets the new parts....
then.... the same guys win.
No different than real racing.
The upper tier will always be the upper tier.

I said "such a small box".

They have all the same chassis and the same bodies. I am just one of the many that does not like the COT theory. I also did not like when Ford would have a better aero package due to the design of the actual car they would let GM and Dodge have some more/less nose/spoiler/height or whatever.

In a sense, yes they have to "work harder" but is seems as they are just having to settle for a car that does not handle as well.

Didn't NASCAR take the yaw away? I thought I read that somewhere. If not, they will.

Maybe you take my comments as I do not want an even playing field. That is not the case at all. Without the rules there would be chaos, that is not what I want to see. But all this, every team needs to have the same chance and we are going to make sure everybody does, is making for some, not all, boring racing.

Every single team has the same chance, they all have the same rulebook. If one team can outspend the other and then outrun them, guess what THIS IS BIG TIME RACING, not your local short-track program where you have everyday guys battleing for a few bucks and bragging rights.

I liked it better when the cars were different and the Manufacturer would make a production car to be better on the track.

Ahhhh progress.

We do agree on one thing, the cream will always rise to the top.

In a sense, yes they have to "work harder" but is seems
as they are just having to settle for a car that does
not handle as well.

The car doesn't handle well.... yet.
Everyone wants instant success..
Look at how long it took them to get the other cars fast..
They ended up with setups and parts 180 degrees from what was
considered 'right' just 5 years ago.
The spring setups on those cars was completely contrary to every
design criteria just a half dozen years ago...

Eventually, they will get these cars 'fast'. It's only a matter of time.
Every time anyone makes cars 'slower' they always end up going 'faster'..


Didn't NASCAR take the yaw away? I thought I read that somewhere.
If not, they will.

Some... not all of it. One degree, now.....they still crab...


I liked it better when the cars were different and the Manufacturer
would make a production car to be better on the track.


me too..

It has been no different for RC. Car setups are ALWAYS the key to winning. Driver talent can only be as good as the car. Look at how much chasiss setups have changed from just a few years ago 6cell stock to 4 cell brushless. The brushless wasn't nearly as fast as the old cars but it didn't take long to get faster than the old stockers. Now we are building smaller motors to keep the speeds down. We were barely faster with 4 cell 5800(8.5) than with 6 cell stock as first. Then after the first 3 or 4 weeks it was equal. Then the floodgates opened and chassis setups and gearing got wild. Now we are down to the 4 cell 13.5 and running faster than the old 6 cell 27t.

Give them time. These are NOT IROC cars. The aero advantage has been dramatically taken out of the equation now. Shocks and springs are the major tool and minor front or rear end settings will make these COT cars race better. Speed is not racing. Tighter rules will make better racing.

Sam and Cliff are correct.
I have experimented with holes in the windshield, vent holes in the rear-side windows, and even running a vent hose thru the car to cool the engine. The best aerodynamics are bodies without holes, and let the body do the work. I only cut an opening large enough for the cooling head on my .12 to stick thru the rear window screen, and that is enough to effectively cool the engine. Also, like Cliff said, but the rear of the body out....that creates enough air flow without effecting the overall aerodynamics

Coyote

About yaw. I understood that the yaw was so effective that Nascar banned or limited the practice by adding more specs.

I had a home built 3 link Oval car that I could use rear steer in both directions. I was using about 5 degree of left rear steer (pod rotated counter clockwise when viewed from above). This is how I got the car to exit the corner perfectly straight with no hooking. The car was yawed a similar angle on the straight. Very visibly yawed. the car was fast this way.

I have a CRC battle AXE at present that does not allow any significant rear steer. I attacked the problem on corner exit with a 1/8 inch spacer inside the left rear hub. This provided torque steer to the right on corner exit and solved the same problem. The car is not quite as fast as my custom 3-link yet. I am working on it.

Battle Axe on left, 3-link on right.
John

John, you could make an adjustable link on the right side. Or I used to run the Trinity Switchblade with the mono ball rear pod and raised the front of the fixed link and got active rear steer. The car would track staight when you were going straight and would give you rear steer when the car was in the center of the turn as the chassis would roll. I had been waiting for a new chassis that used this design but I am not fond of the CRC front end on that car. If you could put am AE front end on it I would buy one.

The fit of the Battle Axe chassis to the lower pod plate is very tight. What I would call a very good fit. Less than 1/32 inch gap. Good bottom aerodynamics. You could only put a minuscule amount of rear steer in the car. I used a huge 5 degrees on my home built car. A small amount might change the handling but certainly would not give a big yaw angle on the straight that would affect aero. It is easy to put an associated front end on the Battle Axe. Same two big screws secure the uprights. The bag Associated front end is available from CRC for about $40. The CRC front end will also fit the older Assciated (pre R5) cars as well for $50. A lot of guys racing mod pan on road in Europe swapped to the CRC Pro Strut front end. I like my CRC front end with the exception of excessive play. I have some more tricks to try though. One would be to loctite the axle block into the plastic steering arm. I think most of the play is there. The rest of the play is somewhat adjustable with clamping screws.
Thanks for the suggestion of raising the pivot height. I have received that suggestion before. I need to sort out the stock car a little better before I try that. I have a feeling I would need to open the gap with grinding before it would achieve any significant rear steer.
John

John,

I have not seen any good pics of this car finished. I am considering buying one to experiment with. I'm glad you can run the AE front end on it. I run mostly 13.5 or 10.5. Do you have pics you could send me? email is allprodjken@embarqmail.com

Thanks

I have a thread on the Battle Axe. The best pics start about 2/3 the way down the first page. The car is on loan from Rick Siebolt who posts here as well. Frank the owner of CRC is sending me a test car soon. Some of you old hands on the oval could give me a hand with tech there. Lots of good photos of the car there.

http://www.rctech.net/forum/showthread.php?t=222869


The thread is totally non profit. Could just as well have been here, but I have been over there a long time.
John Stranahan