R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro On-Road

Reply
 
Thread Tools Search this Thread
Old 08-27-2010, 12:37 PM   #61
Tech Regular
 
Join Date: Feb 2006
Location: Netherlands
Posts: 478
Send a message via MSN to PMSorber
Default Grip is:

Grip is a term describing the total cornering envelope of a race car by the friction component of the tire, the mass of the machine and the downforce generated.

The mass will not change and DF generated can be influenced. The friction is for a big part the result of several components but... too much friction will result in a slow car, less in a slippery car. So there is a sweetspot within the envelope, x kg/cm2 resulting in the best ballanced friction.

So if you raise something that results in higher friction, will you still be on the sweetspot of the whole envelope?
__________________
@ConSult Trading
Team Shepherd, PiraniRC, Sonic and Awesomatix BENELUX
www.team-shepherd.nl
PMSorber is offline   Reply With Quote
Old 08-27-2010, 01:40 PM   #62
Tech Lord
 
wingracer's Avatar
 
Join Date: Nov 2007
Posts: 12,861
Trader Rating: 24 (100%+)
Default

Quote:
Originally Posted by Roelof View Post
Going down to our cars. they are the complete opposite of a good aerodynamic car......
Yeah, our cars are really more like rally cars in terms of downforce and suspension.
__________________
Sean. Certified speed crazed mowron.
Team Shepherd USA
www.ashfordhobby.com
wingracer is offline   Reply With Quote
Old 08-27-2010, 01:45 PM   #63
Tech Lord
 
wingracer's Avatar
 
Join Date: Nov 2007
Posts: 12,861
Trader Rating: 24 (100%+)
Default

Quote:
Originally Posted by PMSorber View Post
Grip is a term describing the total cornering envelope of a race car by the friction component of the tire, the mass of the machine and the downforce generated.

The mass will not change and DF generated can be influenced. The friction is for a big part the result of several components but... too much friction will result in a slow car, less in a slippery car. So there is a sweetspot within the envelope, x kg/cm2 resulting in the best ballanced friction.

So if you raise something that results in higher friction, will you still be on the sweetspot of the whole envelope?
The coefficient of friction (the grip a tire has) and rolling resistance are two different things. Rolling resistance generally goes up only slightly with an increase in friction coefficient. This is why going to a softer tire has very little if any effect on straight line speed but can greatly increase corner speed.
__________________
Sean. Certified speed crazed mowron.
Team Shepherd USA
www.ashfordhobby.com
wingracer is offline   Reply With Quote
Old 08-27-2010, 02:21 PM   #64
Tech Initiate
 
Join Date: Oct 2007
Posts: 29
Default Serpent 733 DLS

I was driving serpent 733 whit the DLS system in european champion ship last week. When i put it on, i took of 1 deg. tooinn off the rear end, that i thougt that i would give me hugh grip in the rear. I also changing springs to same strenght front and rear. Use to drive 2 step harder springs in the front to get enough grip in the rear. And finally i used 35 shore front and 40 shore rear. Used to use 37-40. I tested it and change back to 3 deg tooinn at the rear end. And then the car was very good to drive. Now the wear of the front and rear tires was almost the same. In 1/10 wee use to wear the rear tires more than the front. So i have only possitiv exspirience to this system.
speikey is offline   Reply With Quote
Old 09-02-2010, 06:07 AM   #65
Tech Fanatic
 
Join Date: Feb 2007
Posts: 925
Trader Rating: 6 (100%+)
Default

http://www.youtube.com/watch?v=rFXDAeQjJCY
__________________
TEAM DURANGO CARBON DEX210 - POWERED BY TEKIN RS GEN2/TEKIN GEN2 17.5
TEAM DURANGO CARBON DEX410 - POWERED BY TEKIN RS PRO/REEDY SONIC 17.5
TEAM ASSOCIATED B5 - POWERED BY TEKIN RS GEN2/TEKIN GEN2 17.5
LiL_JaSoN is offline   Reply With Quote
Old 09-02-2010, 06:45 AM   #66
Tech Adept
 
chuakevs's Avatar
 
Join Date: Jun 2009
Posts: 128
Trader Rating: 1 (100%+)
Default

thanks for the infos.

now, i want to try that in my HPI RS4 Super Nitro
__________________
[+] Sole Flyer of self-assembled RC Planes in Quezon Province [+]
chuakevs is offline   Reply With Quote
Old 09-02-2010, 07:55 AM   #67
Tech Champion
 
nitrodude's Avatar
 
Join Date: Aug 2002
Location: Oxnard, CA
Posts: 5,845
Trader Rating: 5 (100%+)
Default

Quote:
Originally Posted by LiL_JaSoN View Post
You cant really see anything, at least the end is funny
__________________
Steven Muller
AKA El Pibe RUFAST? HAHA!!!
Ronin Speed Parts
nitrodude is offline   Reply With Quote
Old 09-02-2010, 11:05 AM   #68
Tech Master
 
foampervert's Avatar
 
Join Date: Nov 2002
Posts: 1,388
Trader Rating: 5 (100%+)
Send a message via MSN to foampervert
Default Aero in R/C models

Quote:
Originally Posted by DS Motorsport View Post
I think you got it the wrong way around.
Aero is everything in modern, high end motorsport (F1, GT1, LM).
Without a proper aero package you are nowhere.
Mechanical grip is easy to create, there is a lot more knowledge which has been documented very well.
Aero is still partly an black art, just look at the recent blown diffusers in F1. A team like Mclaren had it completely wrong on their first outing with it and had to remove it.

You could double the amount of downforce on a 1/8 scale within no time, but because of the crude suspension (dampers) the car would be undrivable, it will upset the balance tremendously.

I think the same about the dax, it upsets the balance of the car. To get the balance back you will have to do crazy things (ultra hard springs, ARB) which takes away the grip you just added.
If you want to do it properly, and I believe it could actually be an advantage, you will need to redesign the entire suspension from the ground up. Especially the front suspension.
Hiya Folks,

Here's a little something about Aero in R/C Models:

Mechanical grip, coefficient of friction, roll centres etc... are all scaled down.
R/C car engineers can use research done on real cars on their R/C designs.
This is because these things are fully scaled down. friction does not change from 1:1 scale to 1:8 scale. Neither do the laws of physics.

Aerodynamics however deal with in the realm of fluid dynamics. Fluid dynamics do not scale down at all.
What works in 1:1 does not work in an exact replica in 1:8. that's why 1:8 scale bodyshells look absolutely nothing like 1:1 scale Lemans or Lola cars. That's because Air does not work the same 1 cm away from the ground as it does 10cm away from the ground. Neither does it work the same at 200kmph (1:1 scale) vs 120kmph (1:8 true scale speed) or 960 kmph (1:8 scaled speed).

Anyways, Aero-wise... we're just playing around with drag and downforce.
our cars are so small that we need to exaggerate wings, spoilers and such just to get a semblance of performance.

Aero is very important but uses a totally different set of rules for R/C Models.
Mechanical Grip uses the same physics principals as 1:1 cars.

Hope this clears it up.

Shalom and God Bless!

-Alexander
__________________
During heats, i use durex for both front and rear, with Hard inserts.

Sorex, i meant Sorex.
foampervert is offline   Reply With Quote
Old 09-02-2010, 11:11 AM   #69
Tech Lord
 
wingracer's Avatar
 
Join Date: Nov 2007
Posts: 12,861
Trader Rating: 24 (100%+)
Default

All very true Alexander, just a couple of clarifications.

1. There is no such thing as "scale speed." A second is a second, no matter what the scale.

2. We really don't care about drag, at least here in the states. Most tracks you will never reach terminal velocity and if you do, it will only be for a moment so who cares about drag? Downforce is everything on American tracks. That's why we love jacked up 909's
__________________
Sean. Certified speed crazed mowron.
Team Shepherd USA
www.ashfordhobby.com
wingracer is offline   Reply With Quote
Old 09-02-2010, 11:17 AM   #70
Tech Champion
 
nitrodude's Avatar
 
Join Date: Aug 2002
Location: Oxnard, CA
Posts: 5,845
Trader Rating: 5 (100%+)
Default

Quote:
Originally Posted by foampervert View Post
Hiya Folks,

Here's a little something about Aero in R/C Models:

Mechanical grip, coefficient of friction, roll centres etc... are all scaled down.
R/C car engineers can use research done on real cars on their R/C designs.
This is because these things are fully scaled down. friction does not change from 1:1 scale to 1:8 scale. Neither do the laws of physics.

Aerodynamics however deal with in the realm of fluid dynamics. Fluid dynamics do not scale down at all.
What works in 1:1 does not work in an exact replica in 1:8. that's why 1:8 scale bodyshells look absolutely nothing like 1:1 scale Lemans or Lola cars. That's because Air does not work the same 1 cm away from the ground as it does 10cm away from the ground. Neither does it work the same at 200kmph (1:1 scale) vs 120kmph (1:8 true scale speed) or 960 kmph (1:8 scaled speed).

Anyways, Aero-wise... we're just playing around with drag and downforce.
our cars are so small that we need to exaggerate wings, spoilers and such just to get a semblance of performance.

Aero is very important but uses a totally different set of rules for R/C Models.
Mechanical Grip uses the same physics principals as 1:1 cars.

Hope this clears it up.

Shalom and God Bless!

-Alexander
Quote:
Originally Posted by wingracer View Post
All very true Alexander, just a couple of clarifications.

1. There is no such thing as "scale speed." A second is a second, no matter what the scale.

2. We really don't care about drag, at least here in the states. Most tracks you will never reach terminal velocity and if you do, it will only be for a moment so who cares about drag? Downforce is everything on American tracks. That's why we love jacked up 909's
Yeah, Im no expert on these things but when people talk about scale speed I get pretty standofish, there is no such thing as scale speed. An object moving at 200mph, is moving at 200mph weather its the size of a pea, or the size of an oil tanker, its the same speed. Or if you want to do in car terms, its the same speed weather its a 1/12th scale RC or a Audi R15+
__________________
Steven Muller
AKA El Pibe RUFAST? HAHA!!!
Ronin Speed Parts
nitrodude is offline   Reply With Quote
Old 09-02-2010, 01:12 PM   #71
Tech Champion
 
Roelof's Avatar
 
Join Date: Aug 2007
Location: Holland
Posts: 6,282
Send a message via ICQ to Roelof
Default

I have played with ground effect and I am amazed what it does at just 50km/h. A full size epoxy plate just fitting in width and length under the body with only holes for the wheels and flywheel screwed against the chassis. Although you can not scale down aerodynamic laws the effects are still there and the needed forces can be scaled down due the weight of a RC car.

I do believe a rear wing created in the right way as a reversed airplaine wing will work much better than a simple piece of lexan mounted on piano wire as we had in the old days. The problem is if manufacturers and organisations are willing to yake that step. A lexan wig is much simpeler and cheaper to make than a real looking car with good aerodynamics.....

Somewhere on this forum there is a project about adding small aerodynamic shaped parts on the chassis and lower wishbones....
__________________
The quality of an answer comes with the quality of the question.
Roelof is offline   Reply With Quote
Old 09-03-2010, 09:44 AM   #72
Tech Master
 
foampervert's Avatar
 
Join Date: Nov 2002
Posts: 1,388
Trader Rating: 5 (100%+)
Send a message via MSN to foampervert
Default air scoop vs actual wing

Quote:
Originally Posted by Roelof View Post
I have played with ground effect and I am amazed what it does at just 50km/h. A full size epoxy plate just fitting in width and length under the body with only holes for the wheels and flywheel screwed against the chassis. Although you can not scale down aerodynamic laws the effects are still there and the needed forces can be scaled down due the weight of a RC car.

I do believe a rear wing created in the right way as a reversed airplaine wing will work much better than a simple piece of lexan mounted on piano wire as we had in the old days. The problem is if manufacturers and organisations are willing to yake that step. A lexan wig is much simpeler and cheaper to make than a real looking car with good aerodynamics.....

Somewhere on this forum there is a project about adding small aerodynamic shaped parts on the chassis and lower wishbones....
Actually, the wing design has been tested before.

I am almost certain every bodyshell manufacturer has considered it before. I certainly have played around with that idea and made wings out of Lexan.

With the type of Chord length typical of wings on R/C car models (1:10 or 1:8 scale), Wings need to have a very thick airfoil section to provide similar lift(downforce) as air scoops (current bodyshell designs).

This makes true airfoils on bodyshells highly impractical.

You can certainly try it yourself. A wing capable of the same downforce as the airscoops will be almost double the size of the airscoop.

If you really want to be a lawyer about it, the airscoop is really an undercambered wing, innit?

things such as gurney flaps really do work in R/C though... but again, it's almost vertical like the airscoop wings we are used to.

-Alexander
p.s. it never hurts to experiment though... have fun! ;P
__________________
During heats, i use durex for both front and rear, with Hard inserts.

Sorex, i meant Sorex.
foampervert is offline   Reply With Quote
Old 09-03-2010, 10:09 AM   #73
Tech Regular
 
Join Date: Feb 2006
Location: Netherlands
Posts: 478
Send a message via MSN to PMSorber
Default

Quote:
Originally Posted by foampervert View Post
Actually, the wing design has been tested before.

I am almost certain every bodyshell manufacturer has considered it before. I certainly have played around with that idea and made wings out of Lexan.

With the type of Chord length typical of wings on R/C car models (1:10 or 1:8 scale), Wings need to have a very thick airfoil section to provide similar lift(downforce) as air scoops (current bodyshell designs).

This makes true airfoils on bodyshells highly impractical.

You can certainly try it yourself. A wing capable of the same downforce as the airscoops will be almost double the size of the airscoop.

If you really want to be a lawyer about it, the airscoop is really an undercambered wing, innit?

things such as gurney flaps really do work in R/C though... but again, it's almost vertical like the airscoop wings we are used to.

-Alexander
p.s. it never hurts to experiment though... have fun! ;P
Impressed! Good explanation
__________________
@ConSult Trading
Team Shepherd, PiraniRC, Sonic and Awesomatix BENELUX
www.team-shepherd.nl
PMSorber is offline   Reply With Quote
Old 09-03-2010, 11:18 AM   #74
Tech Champion
 
Roelof's Avatar
 
Join Date: Aug 2007
Location: Holland
Posts: 6,282
Send a message via ICQ to Roelof
Default

Quote:
Originally Posted by foampervert View Post
p.s. it never hurts to experiment though... have fun! ;P
Oh no, it does not hurt at all and it is fun indeed!

I already have some ideas on the table.....
__________________
The quality of an answer comes with the quality of the question.
Roelof is offline   Reply With Quote
Old 09-06-2010, 11:07 PM   #75
Tech Fanatic
 
Join Date: Feb 2007
Posts: 925
Trader Rating: 6 (100%+)
Default

with all the hype going on, and a bunch of spare parts i came up with this

dax/dls on a rrr..

just gotta o some adjustments, then ill test it.

__________________
TEAM DURANGO CARBON DEX210 - POWERED BY TEKIN RS GEN2/TEKIN GEN2 17.5
TEAM DURANGO CARBON DEX410 - POWERED BY TEKIN RS PRO/REEDY SONIC 17.5
TEAM ASSOCIATED B5 - POWERED BY TEKIN RS GEN2/TEKIN GEN2 17.5

Last edited by LiL_JaSoN; 09-07-2010 at 01:40 AM.
LiL_JaSoN is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Electric Touring / On-Road RC Screaming Wind Manila Racers 32167 05-02-2017 11:20 PM
The Formula One / Mini RC Club oldskul Manila Racers 9272 10-13-2016 06:14 AM
MRX-4X chicky03 Nitro On-Road 1676 09-17-2016 12:34 PM
WHAT DO YOU THINK ABOUT THIS! Seisick Nitro On-Road 12 09-30-2008 12:22 AM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 12:46 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net