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Old 06-28-2007, 05:19 AM   #4681
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Originally Posted by JRXS_chris View Post
Any of you guys experienced a bit of tweak coming from when the battery tray (carbon or kit) is screwed on?
Hi Chris,

Myself and Andy East had my car on the tweak station last night, gave it a twist to see if that bubble shifted and the lil' bugger moved a fair distance outside of the lines.

In order to stop the plates shifting in an impact and staying that way and to stop me having to put it on a board after every race we came up with a solution that Andy used to great effect on his SD tub chassis designs, see pic...

Basically the cutting of the top deck and use of a ball joint means that the car always returns to centre, we did several 'twist' test on the tweak station and the bubble always stayed within the lines. This does produce a little more flex, but with the high power mod motors we are using in 5 cell the extra flex (that doesn't cause tweak) should help. Its fist outing will be this weekend at the Snetterton National...hopeing for dry weather to give it a good go.

Best
Chris
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Old 06-28-2007, 06:36 AM   #4682
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wow, that's drastic.. be sure to give us a report after you run it..
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Old 06-28-2007, 06:41 AM   #4683
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Originally Posted by syndr0me View Post
I still need it to rotate a lot more, but it's an improvement. I can tell it's scrubbing speed on sweeping turns.
I believe Rob mentioned switching to the 1degree block in the rear to fix this.

Later,
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Old 06-28-2007, 06:55 AM   #4684
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You are obviously doing something wrong. My car will not tweak, I have had most of the cars on the market and my car has yet to tweak more than the bubble touching the line. I've tried to twist my car back after a small tweak and its soo stiff that the bubble doesnt move with a twist, which on some other cars would shift the bubble from one side to the other no problem. I dont understand how you think a 2mm wide tie rod is stiffer than a 35mm wide topdeck. I think something else is wrong and you should go back to the regular setup.
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Old 06-28-2007, 06:59 AM   #4685
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Default Pavement set ups

Are there any set ups out there for asphalt that are working well. We are currently using the 2006 Nats set up from Todd Hodge that seems OK, but I wanted to see what some of you guys are using.

Thanks in advance for the help.
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Old 06-28-2007, 07:01 AM   #4686
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I suck at driving and hit a lot of stuff and the type-r resists tweak amazingly well, I kept telling haynes "I can't believe this thing inst' tweaked" even after hits the took out arms. I used to be able to tweak my xray enough to require steering trim adjustment
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Old 06-28-2007, 07:10 AM   #4687
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Hi,

There is very little you can do wrong when putting a car on a tweak station seeing the bubble in the centre, twisting the chassis and putting it back on...the bubble shifted, more so than desired. You say "My car will not tweak" yet in the next line state "I've tried to twist my car back after a small tweak" so the car obviously has the potential to tweak, even if it is marginal it is something that i would like to eradicate.

The car is very stiff granted, but this does not mean it won't tweak, infact it can mean the opposite in that when it is involved in an accident and the two plates do shift it has no means to right itself back to centre.

The turnbuckle front to back is as strong as standard, but the movement of the ball joints allows the chassis to right itself, as i said we performed tests and the result was what we wanted.

There is obviously more flex in the car, but this is what i want, this can be tuned by extending the rear portion of the deck to the struts if needed. The set up I have on there now should produce more grip at the rear of the car, but the flex will not tweak it because of the ball joint movement...i hope that makes sense!

This is a test, no question, but on the pit table it worked, i'm looking forward to getting it on the track and seeing what it does. If you don't try things you don't learn anything!

Chris
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Old 06-28-2007, 07:36 AM   #4688
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Well what i meant is the car is not tweaked when the bubble is off, its something else, the tweak station is not exactly level, the droop is off, the camber is off, the rideheight is off. Something else, hence the bubble not moving when the car is twisted. This is why I stopped bothering to twist the car when the bubble is slightly off.

You dont see any of the manufactures using balljoints at topdecks so there is obviously more than one flaw with it. Also you say the ball joints allow the chassis to twist. That is the point of the topdeck to stop the chassis from twisting not from folding in half front to back.

I have never had the car hold a tweak like all my other cars, I have never had to adjust trim casue of a tweak on this car, unlike cars with different designs.

Im just suggesting you try to get the car to work properly the way it was in testing for 2 years and designed. That is all. Also I am NOT a fan of getting my car to work by making the chassis produce the traction. Thats what suspension is for.
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Old 06-28-2007, 08:19 AM   #4689
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By putting the link in there, you've turned your $80 graphite chassis into a giant T-bar.

Now you have 1/10 scale, 4WD T-bar car with shocks.
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Old 06-28-2007, 09:11 AM   #4690
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2 questions, what can I do in order to have:

1. I need more on throttle steering
2. I need less high speed breaking steering

I'm using front diff.
Thanks
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Old 06-28-2007, 09:27 AM   #4691
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Thanks for your comments Larry,

The fact is that in this RC game everyone has different ideas and theories in car set up and design, both manufacturers and racers alike...this is one of mine.

This idea is not new, we first used it on an SD chassis that won the 27t National series in the UK, will it translate to this car and in mod, maybe...maybe not, but i will give it a go and if its a useful as a chocolate tea pot the original will go back on.

In an ideal world you're right the chassis flex shouldn't be used to get the car to work, but when you're trying to get a car working in a short space of time it can be helpful. With a stiffer chassis the set up window is that much smaller and takes track time to get. That is a major reason why RC car manufacturers have gone from composite moulded tubs back to 2 deck chassis' with thinner chassis as hop ups.

Last thing...honest...I see the point of a top deck to control the flex of the car to a desired level. My set up has the desired level of flex for me both front to back adn left to right.

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Old 06-28-2007, 09:29 AM   #4692
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Quote:
Originally Posted by ioxqq View Post
2 questions, what can I do in order to have:

1. I need more on throttle steering
2. I need less high speed breaking steering

I'm using front diff.
Thanks
Spool it....or at least run thick grease and a very snug setting.
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Old 06-28-2007, 09:44 AM   #4693
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Quote:
Originally Posted by McSmooth View Post
By putting the link in there, you've turned your $80 graphite chassis into a giant T-bar.

Now you have 1/10 scale, 4WD T-bar car with shocks.
schumacher did this with the axis 2, and it ran alright. the problem was that the chassis wasn't stiff enough for turnbuckles on the top. it's actually a solid design for eliminating tweak, but nobody designs the lower chassis stiff enough to use this "tweak proof" method effectively.

the physics that chrissyc mentions are there. the two decks shear against each other, and don't come back all the way. the difference is in the magnitude that this happens for everyone. it sounds like maybe the screws need tightening up a little more so that the shift isn't apparrent. for most of today's cars, the tolerances and general design are enough to keep tweak from being much to worry about. (but yes, it is there)

i played with the tf-5 (shaft car) some this past winter. that car had decks stacked atop miscellaneous plates, and whatnot. no matter how tightly we built it, i could twist the car 1.5* each way on the tweak board. it was so bad that we couldn't even run it because it would tweak out if you hit anything even moderately.

i like the idea here, and i wish it had been further developed by the mfr's. it's fairly analogous to using o-rings under the deck, which isn't all that uncommon, but as larry implies, you're out on your own with a setup for such a beast. considering how well some of folks have the type-r running, it may not be the best way to go just yet.

good luck with it. it's obvious that you have a good understanding of the what this change will bring.
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Old 06-28-2007, 09:58 AM   #4694
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Thanks Seaball,

Didn't realise that Schumacher had adopted the ball joint technique...must be something in the water over here!

Losi have made a nice strong chassis so it forms a good basis, plus the top deck is mounted firmly at the front end of the car with its front and mid pick up points. The rear end is a little more on the flexible side, but then i am hoping it will aid in generating traction to help get the rear tyres working - when running 5 cells with the weight frontwards this is something i was having trouble with. Although as Larry says this is not a great set up technique, but one i will take for now!

There are only a couple of guys running the Losi in 5 cell mod here so set ups are scarce as is trackside assistance from the Team (don't think there is one!), aside from that i like to try things, its part of the hobby i enjoy the most.

The forcast looks set for more heavy rain though so it may be a no go from the start!

Chris
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Old 06-28-2007, 10:58 AM   #4695
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Hi there, Chris

The car looks good, Hope the weather focast is wrong, but cant see it somehow

See you at snetterton saturday

Cheers
Tim
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