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Old 02-03-2014, 06:53 AM   #91
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that book is 100 bucks dang
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Old 02-03-2014, 11:12 AM   #92
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that book is 100 bucks dang
True, but it is an engineering level discussion of how racecars work. I highly recommend it. Not an easy read if you're not up on your math or haven't read many college textbooks lately. You can sometimes find used copies online but they are rare.
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Old 02-03-2014, 11:30 AM   #93
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True, but it is an engineering level discussion of how racecars work. I highly recommend it. Not an easy read if you're not up on your math or haven't read many college textbooks lately. You can sometimes find used copies online but they are rare.
ya I guess well this broke college student doesn't have that kind of cash laying around unfortunately Martins App will have to do
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Old 02-03-2014, 11:48 AM   #94
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My opinion is that when the car is up in the air and running only on the outside edge of the tires, changes in any suspension parameter have little or no effect. Thus the lack of consensus on any change in suspension to keep it rolling the rest of the way over. Traction roll is a tire/track problem insensitive to changes in the car's suspension setup.
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Old 02-03-2014, 12:04 PM   #95
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And driving style also. An experienced driver can adjust to it by braking before entering a turn. On the other hand, an inexperienced driver like me will keep throwing the car into the turns and keep rolling.
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Old 02-03-2014, 12:25 PM   #96
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My opinion is that when the car is up in the air and running only on the outside edge of the tires, changes in any suspension parameter have little or no effect. Thus the lack of consensus on any change in suspension to keep it rolling the rest of the way over. Traction roll is a tire/track problem insensitive to changes in the car's suspension setup.
You don't run a spec tire class, do you?
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Old 02-03-2014, 08:04 PM   #97
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My opinion is that when the car is up in the air and running only on the outside edge of the tires, changes in any suspension parameter have little or no effect. Thus the lack of consensus on any change in suspension to keep it rolling the rest of the way over. Traction roll is a tire/track problem insensitive to changes in the car's suspension setup.
The suspension geometry, shocks springs etc help prevent your car from getting to point you describe ( up in the air running only on the outside edge of the tires.). So your last statement is not correct. Traction rolling is very sensitive to how you setup your suspension.

If your car gets that point of having the inside tire off the ground and running on the outside edge of the outside tire then you are very liikely going to traction roll.
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Old 02-04-2014, 07:24 AM   #98
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Great info Martin. I have had your book and bought your app on both my old Iphone and now my Android.
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Old 02-04-2014, 07:54 AM   #99
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Great info Martin. I have had your book and bought your app on both my old Iphone and now my Android.
Thanks Jason I need to give you a bulk discount

By the way, for those those that don't have an iphone or android app, or are too cheap to buy the app you may not be aware, but I had posted some images of the cheat sheets on the setupworkbench facebook page back on Dec 16 2013, that you might want to checkout.

https://www.facebook.com/setupworkbench
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Old 02-04-2014, 10:15 AM   #100
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I haven't been through this whole thread, Are you updating the App with all this new info Martin? or it'll be all on the website from now on? (either way works great for me!)
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Old 02-04-2014, 01:32 PM   #101
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I just purchased and downloaded your app and WOW it has a lot of info on it! Looks like I have a lot of reading/learning to do. Thanks for putting it all together for us!
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Old 02-04-2014, 04:56 PM   #102
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Hey Martin, I managed to get my hands on the RCVD book and I've been reading up on Chapter 18 - Wheel Loads. The chapter introduction states how important loads at each wheel are in determining the car's maximum steady-state cornering capability.

On page 666. It discusses the different assumptions made in order to calculate wheel loads. What I found interesting is the how the final assumption discusses "'that the chassis of the car under consideration is rigid. If the chassis is flexible..the calculations will not be completely accurate."

I understand we're dealing with model cars, then why do manufacturers opt for flexible chassis design? What are your thoughts on this? Would this not have an effect on lateral load while in mid corner?

Could you explain "Jacking Effect", I assume this is another way of saying traction rolling or the precursor to traction rolling?

Cheers,

Edward Pickering.

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Old 02-04-2014, 07:27 PM   #103
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I haven't been through this whole thread, Are you updating the App with all this new info Martin? or it'll be all on the website from now on? (either way works great for me!)
For now it will be on the website. When time permits, I will likely provide a paid access website that works on mobile devices. That will be easier for me to update and support more devices than I can right now. Dealing with get apps into apple's store is a fairly complicated and time wasting process. Also, this way I can support all devices, android, windows phone, apple, blackberry etc, not to mention desktops.

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I just purchased and downloaded your app and WOW it has a lot of info on it! Looks like I have a lot of reading/learning to do. Thanks for putting it all together for us!
Thank you! Yea it is a surprising amount of work to put that together. Getting a good setup is a huge part of being competitive.
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Old 02-04-2014, 07:46 PM   #104
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Awesome decision on that way of supporting your product. I will for sure buy when available for the windows phone. Any ballpark idea when the site might be ready?

Steve
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Old 02-04-2014, 08:02 PM   #105
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Originally Posted by EDWARD2003 View Post
why do manufacturers opt for flexible chassis design? What are your thoughts on this? Would this not have an effect on lateral load while in mid corner?

Could you explain "Jacking Effect", I assume this is another way of saying traction rolling or the precursor to traction rolling?

Edward Pickering.
It's funny because I have been told that back in the 60s a lot of racers experimented with flexible chassis in full size racing. Now it seems full size race cars like a very stiff chassis, to allow the suspension to do its work. Keep in mind it is easier to adjust suspension pieces than the chassis stiffness in a full sized car.

For sure this is a very complicated subject and I have not done enough research to really do it justice. Having said that I will share what I think I know

First, all chassis will flex, so it is about controlling that flex to change the balance of your car.

In my experimenting here is what I found.

If I make the rear of the chassis more flexible, then the car has less steering and is more stable. Too much flex and the front inside tire wants to lift too easily, which can lead to traction rolling as well.

If I make the front of the chassis more flexible, then the rear inside tire can lift more again leading to a higher potential of traction roll. I honestly can't recall what my experiments on making the front more flexible did in terms of more or less front end grip. Thinking it through, I think it would make the car steer more, but I may be wrong on that...would need to test it again. Something is telling me I might had the opposite results, but I am really not sure. Your memory goes went you get to my age


Jacking Effect:

Well from my research the theory behind a Jacking effect is that if your RC is above ground you will have some jacking. As the roll center gets higher, the more jacking effect you will have. Some people will define Jacking as the car wanting to "pole vault" over the (outside) tire contact patch while cornering, causing the inside tire to lift. This is why a low roll center helps prevent tracking rolling, because it is reducing the jacking effect.

By the way, the opposite of the Jacking Effect is referred to as the "Packing Effect". This happens when the roll center of your car is below ground. This allows the car to roll into the drive surface without jacking up the inside. Again this is why low roll centers are good at preventing traction rolling.

I also prefer the smoother feel the car has with a lower roll center...it is less edgy....but can be a bit too lazy and also can have the chassis rub the driving surface.
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