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Old 10-17-2007, 01:30 PM   #331
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I know that it is a lighter assembly, but what is also important is the distribution of the weight. I=1/2 mr^2 for a cylinder, I think. Inertia increases as the square of the radius. The metal spur adaptor has more weight farther out from the center of rotation. The difference might be close if the metal is very thin on the spur adaptor.
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Old 10-17-2007, 05:08 PM   #332
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Originally Posted by John Stranahan View Post
I know that it is a lighter assembly, but what is also important is the distribution of the weight. I=1/2 mr^2 for a cylinder, I think. Inertia increases as the square of the radius. The metal spur adaptor has more weight farther out from the center of rotation. The difference might be close if the metal is very thin on the spur adaptor.
I think its milled out between the screws i gotta take mine apart tomorrow will let ya know
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Old 10-17-2007, 06:57 PM   #333
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I've been reading on and off on this thread, and wanted to at least share these pics with ya all.















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Old 10-17-2007, 09:09 PM   #334
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Originally Posted by kn7671 View Post
Regarding the LayShaft and pulleys, mine too starting knocking fairly quickly while running carpet foam stock.

To solve I simply disassembled the it to clean with motor spray, then while reassembling, super glued the two belt pulleys together. You will still keep the pins in the assembly, but while gluing them together place a little rotational pressure on each pulley, like your trying to twist them apart. This twist will lock each pin in their min/max play conditions, thus eliminating the knocking for good.

Granted once you do this, you can't disassemble the belt pulleys from the layshaft, but you really never need to disassemble it anyway. The only parts that need servicing are the bearings and spur gear, the rest can stay together forever.

John, clean all that blue crap out and glue the pulleys, I promise you will be happy with the results.
Great fix...Just got done with this mod
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Old 10-17-2007, 10:34 PM   #335
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Jea-3-Thanks for the nice pics and the great paint. Good balance on your car. What kind of shelf did you make for the weights. I notice your battery strap goes with the battery. I like that. I am thinking of making a second battery strap for my second battery. Then I won't need to attach and detach it to the one strap.

Conversion to Foams
I made some of the changes suggested. I am a tooth bigger on the pinion to achieve the same rollout with these 58 mm tires. These tires are a full 5 mm shorter than the rubber tires I was using. This required a change in ride height and a corresponding lowering of the droop. I remounted the body to favor these tires. The front is lowered (slammed) to just clear the stock shock tower. I had to remove 5 mm from the front dam and body sides. (This is an outlaw TC). It looks like the tires have plenty of room for a full 6mm of uptravel front and back. This will help me through the bumps. The track had too much water on it today. Maybe a test tomorrow. Roll centers may or may not need some change. Springing and shocks will probably be OK. If I can get some bite it should be faster. If not I have a new set of rubber tires for the next race. I also have some taller wider foams coming. The Jaco prisms (available at tower). These are 29 x 60 mm. I plan to run those in a couple of weeks or so.
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Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-stratus-foams-002.jpg  

Last edited by John Stranahan; 10-25-2007 at 12:33 PM.
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Old 10-17-2007, 11:13 PM   #336
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Is there a particular reason you are going to use the same roll out with the foam tyres as the rubber tyres? I've always been told you can gear up a bit with foam tyres due to less rotating mass.
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Old 10-17-2007, 11:17 PM   #337
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YYhayyiim suggested this earlier in the thread. I will know immediately on running the car if I can gear up another tooth. Thanks for the tip. Well see. This may all be moot if I don't develop the bite I need.
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Old 10-18-2007, 12:54 AM   #338
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A couple of pics with 30mm foams on the back of my car

GRP 2mm offset on the left and ATS non-offset on the right for comparison


Clearance on the shock ballcup with the ATS tyres


Small groove worn in the ballcup from the 30mm foams, they were on the back I have swapped them to the front since.
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Old 10-18-2007, 05:39 AM   #339
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I think all you will need is .5mm, maybe 1mm, on the rear 30mm tires to keep the wheels from hitting the shock ball cups.
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Old 10-18-2007, 08:12 AM   #340
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Thanks John.

The paint was done by Paintin Pete, for my 10 month old daughter. She loves the car. (always wiping finger prints off )

The tray was made from .080 styrene sheet, found in any LHS's train department, and covered with Parma carbon fiber sticker. However, the car is still under weight for ROAR rules, which my tracks do follow for the weight. Problem I ran into was that the plastic does warp.

Had issues with the ESC / BL Motor, so while I wait for Novak's great service department to fix the issue, I'll make a new tray out of carbon fiber.

The battery strap, does pull off of the battery. I made 2 plastic parts that fit into the holes on the battery strap, and they are glued to the battery. I also cut two more peices of that Styrene plastic that fit into two of the battery slots on the car, and glued them to the battery. Now the battery will not move, but can be removed from the car for service.
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Old 10-18-2007, 11:11 AM   #341
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Quote:
Originally Posted by GreaseMonkey View Post
Is there a particular reason you are going to use the same roll out with the foam tyres as the rubber tyres? I've always been told you can gear up a bit with foam tyres due to less rotating mass.
So that you have a better point of comparison w/ the foam and rubber tire set up. If you have close to or equal gearing you can better test and compare the performance of the two set ups...this is all thrown off if you have smaller foam tires, and larger diam rubber tires...different rollout will give you different results...it could be that if you have the same gearing and run the foam tires at 58mm, vs 62mm rubber tires, your foam tire car will be bit slower down the straight than with the rubber tire car due to the foam tire roll out. The foam tire car will have a bit more low end, and run a bit cooler, but it's be slower- the rubber tire car will be faster. So you need to possibly add a tooth on the pinion to gear closer to the rubber tire car's rollout to mimic the ruber tire car's gearing and rollout and thus have a better comparision point...that's the idea...
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Old 10-18-2007, 06:18 PM   #342
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Foam Tire Track Test
Track very green, dusty. Traction Poor.

Well these are the worst conditions for foam tires. I already know that from running the pan car. Bite was hard to come by. Here is what I noticed from the first run.
The car oversteered on the sweeper and a second high speed turn.
The car oversteered on the slow speed turn using only about 24% of the steering throw. Dual rate all the way toward less steering.
The car had no punch and topped out about mid straight.

I made the following changes.
I raised the wing 1/4 inch. Interestingly, like fathead discussed, this is the height the carpet body has the wing. That body worked better for him. This fixed the high speed oversteer.

I ended up increasing the gear 3 teeth over rubber tire gear before I got any punch out of the car on the short straights. From 10.23 overall to 8.7 overall. Gears below that were probably just spinning the tires from loss of traction and high torque multiplication of the lower gears. I may have to drop a tooth with medium traction available. This was quite satisfactory on the last long run. Speeds were OK. Motor temp was 167F on the bottom 189 on top. This indicated I was finally hooking up a little. The gear fixed the lack of punch.

I moved the upper rear shock mount all the way out (moved it 2 holes), I moved the front upper shock mount to the third hole in (moved it 2 holes). This fixed the low speed steering by taking some away. Notice these movements are opposite of what you might expect because I am running the locked front diff.

Overall the last pack was satisfactory. I made a very long run on the last run. It was not faster than rubber tires on this track condition but may be faster during a race when traction is up.

The car was a little twitchy going around the sweeper. I may lower the roll stiffness by moving the front and back spring tops in one hole. Roll centers seem OK. I may get a slightly more effective wing. Things are looking promising for a
medium traction test one day.

Jea3-Who makes the rear wing on your car. It is a generous size.
Fathead-Thanks for the clearance picture. The one with 2 mm offset looks interesting. I think I lost some width.
John

Last edited by John Stranahan; 10-21-2007 at 09:44 PM.
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Old 10-18-2007, 11:15 PM   #343
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Quote:
Originally Posted by John Stranahan View Post
Foam Tire Track Test
Track very green, dusty. Traction Poor.

Well these are the worst conditions for foam tires. I already know that from running the pan car. Bite was hard to come by. Here is what I noticed from the first run.
The car oversteered on the sweeper and a second high speed turn.
The car oversteered on the slow speed turn using only about 24% of the steering throw. Dual rate all the way toward less steering.
The car had no punch and topped out about mid straight.

I made the following changes.
I raised the wing 1/4 inch. Interestingly, like fathead discussed, this is the height the carpet body has the wing. That body worked better for him. This fixed the high speed oversteer.

I ended up increasing the gear 3 teeth over rubber tire gear before I got any punch out of the car on the short straights. From 10.58 overall to 9.0 overall. Gears below that were probably just spinning the tires from loss of traction and high torque multiplication of the lower gears. I may have to drop a tooth with medium traction available. This was quite satisfactory on the last long run. Speeds were OK. Motor temp was 167F on the bottom 189 on top. This indicated I was finally hooking up a little. The gear fixed the lack of punch.

I moved the upper rear shock mount all the way out (moved it 2 holes), I moved the front upper shock mount to the third hole in (moved it 2 holes). This fixed the low speed steering by taking some away. Notice these movements are opposite of what you might expect because I am running the locked front diff.

Overall the last pack was satisfactory. I made a very long run on the last run. It was not faster than rubber tires on this track condition but may be faster during a race when traction is up.

The car was a little twitchy going around the sweeper. I may lower the roll stiffness by moving the front and back spring tops in one hole. Roll centers seem OK. I may get a slightly more effective wing. Things are looking promising for a
medium traction test one day.

Jea3-Who makes the rear wing on your car. It is a generous size.
Fathead-Thanks for the clearance picture. The one with 2 mm offset looks interesting. I think I lost some width.
John
Nice report John...looks good for the first time under such track conditions. Maybe you'll provide us w/ your current set up and possibly help with a few more suggestions...

Gearing- it seems you have this pretty close now after the changes made.

Oversteering- what oil weight are you running and springs? Any front sweep or out-board toe out? Camber- what's your front and rear Camber?

Rear toe?
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Old 10-19-2007, 07:01 AM   #344
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Setup for Outdoor Asphalt Foam Tire
I will list this again with the changes that I made. The car is neutral with this setup now. Oversteering problems were solved by changes to wing and shock upper hole position.

Front
New Text: Caster 4 degrees, 0 toe
bumpsteer & Ackerman: Steering link outer, .150 shim under a long ball stud in outer hole, inner ballstud in forward hole on bellcrank.
Wheelbase middle front and back.
Camber about -1.5 degrees front and back to wear tires evenly. 1 degree on right front. This tire gets a reverse cone from the sweeper.
Blue 17 lb springs top of the shock 3rd hole in, bottom out.
6mm ride height.
35 weight oil stock piston (#3), .010 inch bevel on bottom of piston hole to improve uptravel.
Camber link inner, low outside, Camber link outer, no washer.
Lower A-arm mounts, long in the upper hole. One thick spacer to move width closer to 190 mm.
Actual Droop 2.0mm
no Kickup
Diff medium cam, holes down. I made this adjustment just to reduce wear and movement of the dogbone.

Rear
Blue 17 lb springs. Top of shock all the way out, bottom in inner hole.
Rear Ride height 6.5 mm
35 weight oil, stock piston (#3), .010 inch bevel on bottom of piston holes.
Camber link inner, middle outside, outer camber link, inner one washer on ballstud.
Lower A-arm suspension mount medium in lower hole. Thick washer +.025 inch shim in back and 1/2 degree hub to give a total 2.75 degree rear toe in.
Rear diff medium cam, holes down.
Actual Droop 2.5 mm

Gearing: LRP sphere comp TC edition, LRP X11 3.5 geared 9.0:1 I may go one tooth less on the pinion when traction comes up.

The setup is a tiny bit stiff for a loose track, but may be just right on race day. Tire wear was minimal. I did use Jack the Gripper as the track was very green.
John
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Old 10-19-2007, 07:44 AM   #345
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Thanks for the set-up info, John...set up looks good, but your're right...its a set-up that suits a high traction outdoor asphalt track. When we ran foam tires on our track, most of the time during practice the track was green. It was dusty...you could actually see the trail of dust from the rear of the car...but the car still worked very nicely. However, when the track was at least blown off, the car really comes to life, and if its sugar watered or VHT'ed...look out.

Anyways, the best set up outdoor low-med traction is to go softer all the way around- We run w/ 30wt oil, and 14-15lb springs (you can use AE silver springs), and shocks moved in to the inside 2nd or 3rd hole. I think that these simple changes will give you much better results on green track conditions.

However, if you're going to wait to see what it can do when the track is cleaned off and traction sprayed, then I guess you'll keep the current set up and test it then and see how it fares. What we do is just run our softer set up on the green track, and use the same set up when traction is good, and go a bit harder if needed...

W/ the rear hard wing...for some reason our cars worked better with the stock wings on low traction situations. It worked best when mounted back about 5mm from the stock position...you'll just have to test and see what works out there...

On the oversteering- If you want to give it a shot, I think running the 30wt oil and AE silvers springs all around, should help alot. You can then try silver rears and blue fronts springs, or Green AE rears and silver fronts. Or just going to 40 shore fronts tires should make a big differece...or 35SH rears w/ the 37fronts...these combos should help noticebly decrease the oversteering. Its just testing and tuning...that's the fun part!

Keep it up

Are you pleased w/ the results so far?

Last edited by yyhayyim; 10-19-2007 at 07:59 AM.
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