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Old 11-05-2007, 06:19 PM   #421
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I imagine the "Scandinavian flick" has to be done quickly like I did, unfortunately. It was subconcious to keep me from turning in too tight and hitting the boards. I'll note that this is exactly the maneuver that Sports Utitlity vehicle owners use to flip their vehicles over after they had a blowout. I have seen one on video. Slight drift to one direction caused by distraction or blowout followed by immediate strong steering in the opposite direction. It is a driver thing rather than a car thing.

I have noticed that some 1/8 scale drivers take the wide line going into our sweeper. I have thought about when is the best time to cover that extra 6 feet out and it seems that it would be at highest speed just before the sweeper. It will be accomplished in the shortest time that way. Now like Syndrome I don't think there is a noticeable difference in times. When you make the radius bigger you can go faster although you cover more distance. Best not to do this left then right movement too fast. I don't think this is a flick just a different approach to the best line. No flicks onroad.

Antiroll Bars (Sway bars)
I have installed the TC5 antiroll bars to solve a particular problem of traction roll. I thought I would discuss them a bit.
With a normal diff if you put an antiroll bar on the front you will increase the roll stiffness there and decrease steering traction.
More of the lateral weight transfer will occur at the front now decreasing the efficiency of the front tires.
So how is this different than just increasing front spring tension. Well it has to do with tire compliance. You want the tires to follow the road irregularities. If you make the car springs too heavy the tires will bounce from hump to hump and not follow the road well. So in effect you add sway bars when you need more roll stiffness and a heavier spring is not desired. More roll stiffness front and back will decrease cornering traction a bit and encourage more drift. The car will be more responsive to input and will be more stable.

Sway bars work similar to a heavier spring but not identically. They add pivot friction to the suspension. The way that they work is to push down on the laden (outside tire) while at the same time lifting the inside tire by the same amount (This is how they resist the roll). Thus there is more lateral weight transfer than with springs; Springs have no way to lift the inside tire. For these two reasons I don't use them unless I have too much traction. Well this is the first time I have had too much traction in the touring car. The Nitros were traction rolling in the main also. We were caught a bit by surprise by the extra traffic at a club race.

Full size car books recommend swaybars front and back when they are used.

The installation went well, but we did not get an assortment of bars. I would have put equal bars front and back since the cars oversteer understeer properties are balanced perfectly.

Note that with a locked diff the heavy front sway bar should do the opposite and add more steering. I put the big one in the front and will probably require a spring position change until I get a big one for the back. It should add a bit of steering.

You can see that good wear pattern in the tire if you look hard when you load the pic up to full size,
John
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-anti-roll-bar-front-tc5-003-resized.jpg  

Last edited by John Stranahan; 11-05-2007 at 06:56 PM.
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Old 11-05-2007, 09:04 PM   #422
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stlnst-Thanks for the current NiMH weights.
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no problem bro.
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Old 11-05-2007, 11:00 PM   #423
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Hey John,
about the roll stiffness, how would making the roll center higher differ from adding a sway bar? They both reduce body roll and don't affect how the car handles the bumps.
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Old 11-05-2007, 11:04 PM   #424
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Roll center is instantaneous roll stiffness, springs and roll bars only develop roll stiffness once the car has rolled over.
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Old 11-06-2007, 12:45 AM   #425
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I knew that, but would you be able to get a similar handling car?
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Old 11-06-2007, 08:45 AM   #426
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Drew-You would get a similar handling car. There is one important difference that would make the sway bars better for my case. Suspension forces act directly on the roll center. As you raise the roll center you start getting an upward tilt to this force. You start getting what is called suspension jacking. The suspension lifts a little as cornering forces get higher. This is bad for roll over conditions as it makes the problem worse by raising the center of gravity a little in the corners. Carpet guys tend to use low roll centers as a result and increase roll stiffness with very stiff springs as the carpet is generally smooth. I am going to try the same springs and use fairly stiff roll bars.
In the schematic the upward tilting arrow is the cornering force developed by the tires. It acts on the roll center. The short fat arrow aiming up is the upward component of this force that causes the suspension jacking.
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Old 11-06-2007, 03:07 PM   #427
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Thanks John.
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Old 11-06-2007, 04:31 PM   #428
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Drew-You are welcome.

Adamge-I have had a chance to ponder your post. If I take a lever and push on a spring with it, it seems to me that the effects of a stiffer spring or shortening the lever handle would both be immediately felt. It would be harder to push the lever. There is no slack to take up.

Track report
Cool medium Traction

We had a lot of traffic on the track today. Early birds preparing for the Nationals. Traction was as good as on race day. This would be a good test of my changes. First I took some .060 piano wire from the hobby shop and made a matching sway bar to the larger one in the kit. It is a simple shape so this was easy. I put the car on the track and handling was perfect. No need to adjust springs. I used the same set of tires that traction rolled previously. I ran .1 seconds quicker for the most part with no tendency to roll. Fast lap was 18.4, I had many 18.6. The car was a bit easier to drive fast from the extra stability of the swaybars.

I put on the prism foams with suitable adustment to the upper shock positions for the extra steering they provide. I was .5 seconds slower again. I don't think my car is going to like foams on this track unless they sugar it some months down the road. There is not enough texture for my light car. I put the rubber tires back on. The Nitros, on foam, were hooked up very well on it today. The fastest guys were running about 1 second faster than me, but there were an equal number slower than me.

I broke a second drive axle on the rear this time. The pin is gone. Spare parts and the heatshrink trick are on the way.
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Old 11-06-2007, 07:05 PM   #429
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Here is the Drive Axle Repair Results. I don't have the MIP rebuild kit in yet. The pins on the old kit are too big. I have some .060 piano wire that made a good replacement pin. It only needs to be polished down about .001 to fit well. You can compensate for wear with it by polishing it just to fit. I used Verndog's tip. I had some 1/4 3M quality heat shrink which I stretched to fit over the joint. I filled the joint with synthetic grease and shrunk it. I will give it a test tomorrow. It seems to flex freely enough.
Also note I am using Losi thick graphite hex adaptors. The are .002 inch bigger outside diameter than the Associated Aluminum part. The Aluminum part has been rocking back in forth in the wheel and has destroyed a couple of wheels. The points have even rounded off. This Losi part fits snug and is lighter.
John
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Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-drive-axle-repair-tip.jpg  
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Old 11-07-2007, 02:27 AM   #430
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John,

have you ever considered trying narrowing down your foamies? The 26 and 28mm TC foams are designed for use on much heavier 200mm nitro cars. Maybe with your light car, there's just not enough weight and too wide a contact patch for them to grip properly. (Rubber tires tend to have a more compact contact patch) When we ran foams on electric TC's, they were not 28mm wide, more like 23 ... 25mm. And most of the time slightly narrower at the front.
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Old 11-07-2007, 02:38 PM   #431
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Elvo-I will consider narrowing those tires later. Today was not a good day for experiments as the track was busy.

I did get to run a pack. Traction improved a little over yesterday. I did get in one short chase and pulled an 18.1. Starting to get into 1/10 electric pan car territory(17.8s). 18.5's were more typical running by myself. I tried to get an extra tenth running the last third of the sweeper tight and traction rolled the car again. This was late in the pack. I probably just need the next heavier traction bars which are coming.
The Associated spool and pin pillows are a bit of a mess now. I noticed the pillows were out at one big supplier. I made a spool from the stock associated plastic parts which showed some promise. It has some flex in the outdrives so pin pillows are not needed. The TiR parts are not in yet, its been 14 days. I'll send them a note. My order of pin pillows are not in either.
I used a X-acto to mark three holes with pulley and bearings onboard one of the outdrives. I drilled the 3 holes with a .060 drill using a Dremmel. Drill one side and then use it as a drill guide for the other. Redrill the left side .075 for clearance on the threads. Countersink the heads a bit with a 1/8 tile X-pattern zip bit. Assemble with long #2 screws. Then super glue the rims of the pulley halves to the pulley. It is not lighter than the spool but the car was faster. The flex is the good feature.
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-front-spool-006-resized.jpg  

Last edited by John Stranahan; 11-07-2007 at 05:55 PM.
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Old 11-07-2007, 06:42 PM   #432
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Hey John,

Sent you a PM with an excel attachment you mind find interesting

Regards
Ed
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Old 11-07-2007, 06:51 PM   #433
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Ed-I did not get a PM. I am not aware that you can attach anything to it. Do it by e-mail at [email protected]
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Old 11-07-2007, 08:38 PM   #434
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he Associated spool and pin pillows are a bit of a mess now. I noticed the pillows were out at one big supplier. I made a spool from the stock associated plastic parts which showed some promise.
John...LPH APH has been a very good supplier to me. They have 4 sets in stock if your waiting.

http://www.losipartshouse.com/servle...il?sfs=44aad7c

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Old 11-07-2007, 09:08 PM   #435
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Kevin-Thanks. I have pin pillows coming. Probably tomorrow. I really want the TiR parts to come in as I don't like the Associated Aluminum Spool. I sent TiR an e-mail inquiry today about my order. I like my plastic spool. There was no wear on it. The car was faster than ever.

There might be less activity here for a few days as the Nitro Nats are occupying the track. Interestingly The Eibach Sway bars are going on to my full size Ford focus at the same time I added them to the electric touring car. There is more similarity in tuning small and large size cars than you might imagine.
John
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