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Old 06-29-2009, 02:53 AM   #901
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Quote:
Originally Posted by tjompa View Post
100 tooth on the spur and around 17-20 on the pinion, i have a 6.5 and my sweet spot is 100/24 on large tracks. (untill i get my 4.0)
good luck.
kool just found some 48P gears. will be using a 110/19 combo for the 5.5
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Old 06-29-2009, 04:40 AM   #902
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World GT, Petite Le Mans (2s LiPo, Novak 10.5)

We have 20 cars lined up for our inaugural race which will be in 2-3 weeks as final touches are done to prepare our recently resurfaced track. About 17 of these cars will be Gen X 10ís! Way to go CRC.

Some Comments about a Spec Class:

Specified (spec) Battery
There is quite a bit of resistance to a spec class in general for racers unaccustomed to them, so I thought I would discuss this a bit.

First LiPo batteries - Of course everyone wants to use the LiPo in their kit already. We did two experiments. First I had selected an Orion 3800 as our spec pack. ROAR approved safety. I already knew this was not the fastest pack on the market, but it is made by Kokam. Kokam has the best Lipo safety from videos I have seen of overcharge tests. They have top notch electrode punching equipment that eliminate the burrs on the edges of the electrode. These burrs may cause shorting of the pack and pack destruction later in the packs life. They have a clean assembly environment to reduce the amount of metal flakes in the air that cause the same problem when these flakes settle on the assembly line materials and are sandwiched into the cells.

Recently we tested a Thunder Power 3200 mA-h 40 C pack. I have tested a Thunderpower pack previously and it was very good. This pack had 7% higher average voltage than the Orion pack. That was the first test. Now the track test. Jason and I had two similarly equipped Gen X 10s. With our spec Orion Pack we entered the straight right after each other. We would enter the sweeper side by side. Now I put in the Thunder Power pack. We enter the straight right after each other and I have a 7 car length advantage at the end of the straight for the first few laps. This tapers off to a 3-5 car length advantage later in the run as the superior capacity of the Orion pack helps out a little. I get less grumbling now about having a specified brand of pack. Now the grumbling is about the motor specs.

In my dyno testing on the Home made dyno using a Novak Sentry thread. I found a lot of difference in motor power as you varied brands and varied models of the same brand (older vs newer). How much difference? I have quite a few 3.5s. I tested old X11 and new X12 LRP motors. Old HV and new Ballistic Novak motors. There was a huge 17% difference in motor power from 690 to 800 Watts (the dyno graph is posted earlier in this thread). I donít have a big set of 10.5 motors to test, but I would expect differences of say 10%. That is probably going to be the same 7 car length advantage. No amount of drivers skill in the corners is going to beat that 7 length advantage on every lap. The point of this is to explain why I chose a Specified brand for the Power Plant. A Novak SS 10.5. ROAR has made some efforts to reduce these motor differences by providing specs for 10.5 motors. ROAR spec 10.5 motors will be more similar than non spec motors. I still expect a 3 percent difference. I would like a 1.5 percent difference I normally see between two identical motors. This will insure a drivers race rather than a battery or motor war type of race. We may vote in to use any brand of ROAR spec motor after the next race. What will happen if we open up to other brands is that everyone will end up purchasing two or three brands to find the best in his car. So that old motor (you had in your box) being accepted is not going to save you any money in the long run. You will have the motor of the month syndrome sucking your wallet dry.

First exhibition race World GT, Petite Le Mans, 2s Lipo, Novak 10.5
We had 10 of the 20 Petite Le Mans class World GT racers available at a practice session this Sunday. We were able to line up 7 cars at once for a little exhibition race. Gen X 10 finished 1, 2, 3. My car finished first. The main advantage I had was that my car would not tend to spin out the rear end on corner exit as much. It had way fewer errors. This stems from my efforts to move weight back. Even at the expense of having it a little higher than desired. See the photo. Now if CRC would produce those nerf wings that I drew up, I could put that weight back and low. A second driver, Phil, Drove my car later on and had similar good luck, so itís not just me. There are some advantages to the setup.
General notes. I did not lap anyone over the full six minutes. Racing was tight. There were 3 to 4 lead changes to add to the excitement. People had a great time due to the closely matched but also fairly quick cars on our long outdoor track. This power plant is certainly not ďstupid fastĒ if the track is large; it is as slow as can be tolerated by an intermediate skill level driver in my opinion on a large outdoor asphalt track. We have a beginners class for those not at that level yet.

Setup for Outdoor Asphalt, Gen X 10

Front
Purple Progressive CRC sourced spring. Pointy side down, no spring cup or spring bucket. This maximises clearance from wheel to kingping. The stiffer than stock weight keeps that chassis left edge and the front of the lower pod plate off the ground in the sweeper). Wind tunnel Racing purple progressive spring at lefthander-RC.com or teamCRC.com
BSR Purple fronts (this, any front tire, is a variance from the World GT rules which I insisted on for use on a long outdoor asphalt track)
1mm droop, set the car down on the tires, look at the gap that develops between the knuckle and the lower A-arm outer pivot. This will be the droop.
6 mm Height (I am having a little trouble with this as my tires get very short. I will report what I come up with. At present I have one Associated Aluminum #8 washer under the arm to raise it as high as possible without any modifications.) When using the plastic CRC ride height spacers I am grinding off the conical projection at the top so I only have to mess with the big screws.

0 toe in
-1.5 camber
4 degrees caster
0 degree reactive caster block
Front Diffuser (this really helps on the sweeper and also helps to cool the motor). This is made from an HPI GT plastic wing

Back
White Tweak springs
35 weight oil in RC18T rear side shocks, You need a couple of new ballstuds

Center shock
40 weight oil in center shock.
I put a little .010 inch wide bevel on the front/top of the piston holes by hand with a drill bit and magnifying glass. This allows an easier suspension movement up in bump and slower return to center. I am keeping my tires well planted now in a section that has a little ripple in the pavement.
Silver medium 14.5 pound/inch Associated spring with RPM lower spring seat (or Losi or Associated spring seat). This spring is longer than the stock Losi springs.
Ride height 6 mm, Pod level
2 mm rear pod droop, Pick the car up, eyeball the pod droop at the very back of the pod compared to the chassis back end. It should bend down a bit.

Power, etc
Novak SS 10.5 geared 72/21
Motor Trim ring removed, Last Week we had air temps over 105 F and track temps of 150 F. My motor stayed cool.
Orion 3800 carbon edition pack
Ballast added to bring the car to 42 ounces, our local spec weight.
Old LRP sphere competition speed control with the latest Worlds edition cooling set.
Optional long links
Optional extended body mount plates
I used the original body mount plates to make little platforms to move my electronics back.
Hitec HS 5245 MG, Mighty mini, metal gear, digital servo. So far this is holding up.
Optional GFR micro adjustable body post, but with standard body clips. These are working out just super after converting them to body clips. Note body clip style uppers are now available from lefthander-RC.com

Tire Prep-Kingsford Charcoal Lighter fluid or Corally "Jack the Gripper" The stinky Suntan Lotion on top does not really improve things.

Pic: My very nice looking Gen X 10 with my Track Power practice pack.

A big thank you to Joe, SWtour for teaching me about spec classes. So far it is working out super as soon as the guys put their cars on the track and they don't find people flying by them on the straight and find the cars very evenly matched.. Nothing is more exciting than side by side racing and swapping leads back and forth.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-gen-x-10-after-first-exhibition-race-002.jpg  
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Last edited by John Stranahan; 07-03-2009 at 05:18 AM.
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Old 06-29-2009, 01:18 PM   #903
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Front Diffuser, Tapeless Install

I put the diffuser on with 5 2x56 screws from CRC's roll center kit. I spaced it with two flat 2x56 standard nuts. Then I put on 5 CRC red 2 x 56 Nylock nuts. Looks nice. Should work almost as well as with tape. It will be more rugged than the tape as the front can drag once in a while now without cutting the tape joint. Thought you might want a look.

I am using HPI plastic GT wing for the diffuser. Trim to fit.

A diffuser basically spreads the air that passes by it. I have a car wide layer 6 mm thick of air passing under the front dam. If we keep it in laminar or smooth flow with a small horizontal section of wing and then spread it apart with the rest of the wing, and the road as a base, we create vacuum where it is most effective. Right at the front. You also divert part of the airstream above the bumper (trimmed down Kydex) to cool motor and speed control. Win Win Win. No extra drag, a small extra weight, but I can reduce ballast. I am trying this Sophia body next. I should be able to give a report on Sophia vs R34 GTR outside in a few days.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-diffuser-tapeless-install-sophia-bottom.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-gen-x-10-after-first-exhibition-race-002.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-diffuser-tapeless-install-sophia-top.jpg  
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Last edited by John Stranahan; 06-29-2009 at 01:33 PM.
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Old 06-30-2009, 04:19 AM   #904
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JJS Pro 10 updates
This chassis was my first Pan car, a CRC Pantoura. Since then it has undergone hundreds of little experiment to become the JJS Pro 10 wide pan car prototype. I have a couple of packs now on the new asphalt. It took the first to get a feel for the car and make required changes. Yesterday, on the second pack, all I can say is "Oh My God this thing is really fast now". It was already as fast as the 1/8th scale spec class cars. Maybe the mod 1/8th scales have something to worry about now even with a good driver. Here is a list of some recent changes as well as some summaries of experiments that were done to achieve the suspension the car has now. It has a 3-link rear end with vertical coil over shocks (see photo 4 below and photo 3 in the next post) with Panhard bar (photo 5) and a fully dampened dual dynamic A-arm front end (photo 1, 2, &3)

Front end
I have recently photographed a front end similar to this one. I updated this one by Lowering the A-arms. This was done by attaching them to the bottom of the graphite adaptor plates that let the lower A-arm swing up and down on T-bar pivots. I increased the length of the kingpins to a very long almost won't fit in the wheel 1.7 inches. That gives the arms more mechanical advantage, more leverage over the camber of the wheel. I readjusted roll centers by playing with the spacers on the kingpin, adding a single #4 washer under each of the lower A-arm inner pivots, and by taking out the CRC roll center kit on the upper A-arm inner pivot. As you can see you have a lot of handles on roll center with this suspension. Also you will find out, by drawing roll center sketches, that the roll center adjustment is independent of the camber adjustments unlike with a sliding kingpin suspension. I ended up with a roll center close to the ground (See photo 3 from the front). This is good for outdoor asphalt. Note, in photo two, how low the A-arms have gone. Inboard they are flush with the bottom of the chassis. I have removed some ribbing for better air flow down below the arms. By the wheel the arms are above the chassis giving the arm the proper angle to achieve the desired near the ground roll center. This front suspension has proven to be extremely rugged. Even more so than the standard sliding kingpin suspension which has proven to be very robust. Note in pic one the revised upper plate. It is stronger than before. It has no lightening holes. The cross piece dimension is a little wider than before. I will be trying to offer a kit to put this suspension on a Gen X 10 that you may want to make wide for some high speed work. Maybe CRC will pick it up or if not a private subcontractor. The front end takes advantage of many CRC parts so that crash parts are readily available. The performance is just outstanding in every way. No blowovers. Huge cornering grip. Perfect wear pattern on the tire. Easy tire wear compensation.

Gear Ratio
I am running my most powerful 3.5 in this car. It is an early version Novak HV 3.5 that dynos over 800 Watts on a 2s Lipo battery (746 Watt = 1 Horse Power). I was running a 90/12 gear on the old asphalt. I upped this slightly for the new asphalt which has a slightly longer straight and also for the fact that we come onto the straight with a little more initial speed on the current layout. The layout also flows better with turns that are not quite as sharp as the previous layout. I am running 93/13 now. Gear mesh is markedly improved over a 12 tooth pinion. Braking is butter smooth now. Top speed should be higher than the previous layouts 54 mph. The car seems to jump to top speed in only about 15 feet now. After this the car is just a blur. I passed a 10.5 powered World GT pan car yesterday on the straight. It seemed that I completed the straight while the other car moved only about 4-5 feet. This 10.5 powered car does achieve 45 mph at the end of the straight. The Pro 10 has a lot more grip than before even though the track was quite dusty yesterday. The chassis came back covered with white dust from construction which is near completion.
I will explain my perfected motor and speed control cooling in the next post. At 105 F and 150 track temps the speed control and motor temps were only about 160 F. Scooping high velocity air onto the speed control really does the trick.

Roll Stiffness
Fourth pic, blue rear springs.
On the first pack I determined the car was a bit sloppy and also it had a mild push on the sweeper. I lowered the front spring stiffness to get rid of the push. I raised the rear spring stiffness by a large amount, from a Associate RC18T gold spring .032 wire thickness to a .046 inch CRC blue side shock spring. I removed one coil. I bent the cut end flat using vice grips and pliers. I sanded it flatter with a stationary belt sander. On the track the car was perfect. All the twitchiness and imprecision was gone. We had a World GT pan on the track first. There was enough dust on the straight to leave a rooster tail of dust behind the car. We slid around a lot. Then I drove the wide pan car and had excellent traction (the previous car had in fact scrubbed the track some). Steering precision was outstanding. Transition from left to right hand turning was handled without the back end undergoing a huge twitch. In spite of the huge increase in spring stiffness (about 3.5 lb/in to 12 lb/in) The back end is still supple in roll because the shocks and springs are inboard of the rear tires. This reduces the leverage they have to control roll. This may be the ideal position for the coil over shocks.

Panhard Bar
The fifth pic shows the position of the Panhard bar and the screws required to mount the ball supports. Multiple experiments with many cars and many Panhard bar positions has shown me that the car is fairly insensitive to Panhard bar height or Panhard bar length. We only wish the Panhard bar controlled rear roll center. It does not. The pod acts like its own separate little trailered 2 wheel car and has a roll center at the center of the axle regardless where you put the Panhard bar. Given this data, it is reasonable then to use a short bar with mass down low. There is a nice little space produced by the curvature of the motor can just in front of the motor near the frame. All my future Panhard bars will be short and will go here. The ball supports on each end must have two screws for support to prevent rotation. On one car a hole drilled in front of the motor plate down low proved a good way to mount the right side. On this car I am using a slightly longer bar as I have more pod material, on my custom made pod, to mount it on the right side, than on a stock lower pod plate.

Rear of car
Pic four again.
This pic shows the relative positions of the shocks. The pod dimensions that I like position the left side plate exactly where a narrow pod would have it. The motor plate is exactly where a wide pod would have it. This produces perfect balance if you include the weight of half the lead wires on the motor. It also allows you to run a standard rather than extended pinion and a standard wide pan right hand hub. Left and right hand hubs are more closely matched in length to give each side of the axle similar spring.

End Result
Your next generation of pan car may look like this. Gone is the wasted rotary motion of the pod. Gone is the fifth shock. Gone are blowovers caused by lack of front damping. Gone is the poor camber control of the sliding kingpin suspension. Gone is the bad scrub of the sliding kingpin suspension; the tires are not dragged sideways across the road as the wheel goes up into bump. Achieved is a very stable easy to drive extremely high performance platform for the fastest of the brushless motors. Achieved is a very high antisquat value that helps this car penetrate the dust and get great forward traction. Anticipated use will be on large 1/8th scale tracks. The 3-link rear and dual A-arm independent front also worked great on the oval with 13.5 4 cell. The big track is not the only possible use.

Motor cooling Success Next Post.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-jjs-pro-10-front-suspension.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-jjs-pro-10-bottom-front-arm.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-jjs-pro-10-front-view.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-jjs-pro-10-back-pod.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-jjs-pro-10-panhard-bar.jpg  

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Last edited by John Stranahan; 06-30-2009 at 04:56 AM.
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Old 06-30-2009, 04:43 AM   #905
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This is a continuation of the above new post

Motor and Speed Control Cooling Success
There is nothing like a 60mph blast of cooling air each lap to cool things off in even the hottest conditions. I placed my speed control on my top deck so that the heat sink just slightly protrudes through the body. I put on the duct which I have described and photographed previously. I took OFF the cooling fan on the speed control.

Earlier in the week with 105 F air temp in the shade and 150 F track temp the speed control was just below track temp after a 4 minute run. 137 F. The motor was the same. Yesterday with better traction but still 103F air temp the motor was 167, the speed control 157 after more than 6 minute run. I can just run it until the pack is exhausted even with 6000 mA-h on board.

You guys in the middle east and in Malaysia should try this and give me a report.

After a run put the car on a little fan or tilt it up against a floor fan.

Note the duct position is the same as the radiator cooling duct in the full size car. It draws enough air apparently to cool the speed control and then the motor as well. Handling is unaffected.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-peugeot-905-b-908-colors-resized-006.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-peugeot-905-b-908-colors-010.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-jjs-pro-10-tc-edition-less-fan-up-high-duct.jpg  
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Old 07-01-2009, 08:14 PM   #906
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World GT Petit Lemans Edition (LiPo 10.5)

Everyone that drives the class really enjoys it and tell me so. The specified Orion 3800 battery and specified Novak 10.5 motor has made the running really close. On a long track the speed and quickness of the car is a real delight. It is slow enough to concentrate and achieve an almost perfect line. It is fast enough to keep the interest up on a long track. So how fast are we going. With incremental improvements in setup I am now at 48 mph on the straight. Wow. From a 19 turn equivalent. Our new smooth asphalt is helping here. This is up from 46 mph just last Sunday. That happens to be the same top speed achieved by a number of 3.5 powered but stock suspension wide pan cars on our somewhat bumpy old track. They did get to top speed a bit quicker and then the somewhat antique rear suspension limited further speed gains over the bumps. My 3-link rear used to get to 54 mph. Imagine that 5 mph gain from just removing one shock and adding an extra beefy center link in its place plus a Panhard bar.

Now back to the World GT. Some of the gains were in gearing. It is now 21/72. That is probably lower than some people have told me they run. The car is very quick out of the corners when traction is available. It was last weekend. It also has higher top speed. This is also the same gear I used to run on the old dusty layout because it controlled wheel spin mid straight on. As a bonus the motor runs only at 150 degrees in 140 F track temps.

The other gain was from going to the Sophia body. It certainly is sleeker than I was running the R34 GTR. Now the problem for me was to get it to steer. I did have to add a couple of clicks of dual rate to move the steering wheels a little farther with the same input from the driver. The under car diffuser that I pictured previously did all the rest. The Sophia was planted on the sweeper. This same body style was used by a couple of other drivers on Sunday. Their cars were pushing. A solution used was to go from my reccomended front purples to spec or even pink fronts. This helps, but you will find the soft tires wear many times faster than the purples on the front on a long track with a sweeper. It is best to get the steering by other means; Taller hood, undercar front diffuser, softer front springs, but not so soft the chassis starts to drag in the turns in the back. Note I used the same J Concepts large Illusion wing on both bodies. It meets Pan car GT RO
AR specs rather than world GT specs, but is much better suited on a long outdoor track at 48 mph.

Preparations continue for a race. This spec class like stock class deserves special attention to the wiring. It is not quite a powerful mod. You can make small gains by using the shortest lead wires consistent with easy pod rotation and smooth wire curves. 12 gauge is also appropriate here. See the pic. I have swapped sides on the receiver because this battery has the plus lead on the opposite side of the car as my track power. I absolutely hate these bullet plugs and the extremely tiny + and - details on this Orion pack. (I chose it for safe chemistry). I cut away some plastic and soldered deans female half plugs directly to the tubes. I used some flux and a very hot iron so that the solder that holds the tube to the circuit board would not be affected. Most racers will not tamper with the harcase battery, but you can make up leads on the speed control with short wires so they just plug in and will not plug in backwards. That is the main accomplishment.

I replaced the three large motor leads with 12 guage. I made sure to leave enough slack for smooth curves and easy rotation of the pod.

Pics of the Sophia Body and previous wiring from a previous post.

quote from a previous post
"A diffuser basically spreads the air that passes by it. I have a car wide layer 6 mm thick of air passing under the front dam. If we keep it in laminar or smooth flow with a small horizontal section of wing and then spread it apart with the rest of the wing, and the road as a base, we create vacuum where it is most effective. Right at the front. You also divert part of the airstream above the bumper (trimmed down Kydex) to cool motor and speed control. Win Win Win. No extra drag, a small extra weight, but I can reduce ballast." Attached Thumbnails

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Last edited by John Stranahan; 07-01-2009 at 11:01 PM.
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Old 07-01-2009, 10:30 PM   #907
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John,
I run my SpeedPassion 10.5 at 19/70 to 21/70 depending on tire size on a large track. So I think you are in the same gearing range.
I do run it with my trusty old Novak GTB.
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Old 07-02-2009, 07:17 PM   #908
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Quote:
A big thank you to Joe, SWtour for teaching me about spec classes. So far it is working out super as soon as the guys put their cars on the track and they don't find people flying by them on the straight and find the cars very evenly matched.. Nothing is more exciting than side by side racing and swapping leads back and forth.
John,

My PLEASURE!!

Now that IS what racing is all about...Isn't it??

Joe
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Old 07-03-2009, 06:29 AM   #909
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Hey John

I'm planning on building a new front end for my 200mm car. my modified AE front end is about 4mm too wide (cause I measured something wrong ) and a bit sloppy.
Now i want a double wishbone suspension instead of the kingpin-thing. Because my car is about 60gr underweight, there's a lot i can do (Probably with some Tamiya TRF shocks).
Now the question. What camber- and castergain does your suspension(-s) have?
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Old 07-03-2009, 07:26 AM   #910
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Thanks for the post guys.
Pro ten-Thanks for the gearing report.

Der-Dickey
My front suspension does not have any caster loss with roll at present. You can however install a 4 degree or 6 reactive caster block instead of the 0 degree block. I don't think this is needed with a double wishbone suspension.

Some history of my Front suspension
Firstly there was no computer involved to design the suspension ahead of time. It was trial and error much as we select the proper gears for a course. The lower arm has been more or less a fixed length. Nice and long. On one older version I could adjust the length of the upper and lower arm longer or shorter with shims. I settled on the current length and length difference based on best cornering. It turns out an Associated front arm is a good length for the upper. Once you build the longer lower arm, this sets your negative camber gain with bump. I suspect that I have more negative camber gain with bump than an Associated front; I have not measured it. More important is that I have much less scrub across the pavement as the tire goes up into bump. This is well illustrated in Carrol Smiths "tune to win" for a double wishbone. I can tell this from the much improved wear pattern that I get on the front. It is not scrubbed smooth. I get ripples around the circumference much like a hooked up rubber tire gets.
It would be difficult indeed to find a superior shock and spring position to the one I am using now. I have many pictures of it on two different cars. If some dimensions would help, I can provide these.
This suspension I built most recently requires you to manufacture only 3 flat graphite plates. It is so easy and so good on the track. I will be providing CAD drawings eventually. It may go on to production. This is about the 6th front end in a series. All are photographed in this thread and in the Pantoura thread. None are as easy to build by hand as this last one.




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Last edited by John Stranahan; 07-03-2009 at 07:37 AM.
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Old 07-03-2009, 12:53 PM   #911
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The RC18T rear side shocks....not mount springs?
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Old 07-03-2009, 01:29 PM   #912
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World GT Petite Le Mans

You can run springs on the RC18T shocks. On the world gt car I decided to retain the stock tweak springs in stead of coil over springs on the shocks. Today I decided to run with just one shock ala RC10R5. It worked fine. On the two wide pan cars with vertical shocks, I will probably end up using coil over shock type springing in order to have a bettter selection of spring rates and also better spring retention in an accident.

The wide pan reached 64 mph on our new 190 foot straight. It seems like it reaches top speed very early only 30 feet into the straight. I am geared 93/13. I may be able to go 93/14 as speed control and motor temps are quite low at 151F with 101F air temp and 142 F track temp.
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Last edited by John Stranahan; 07-03-2009 at 01:39 PM.
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Old 07-03-2009, 11:22 PM   #913
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JJS Pro 10
The wide pan was the equal of a Nitro TC on our new more flowing layout with virgin asphalt both cars with equal drivers. I think I can go faster maybe using some of Pro-10s tricks. The car reached 64 mph and maintained it through the sweeper. Motor temps are only 150 F at 103F air temp and 143F track temp. I geared up a tooth for tomorrow by going to a 87/13. This moves the spur just flush with the bottom of the bottom plate, so it is better protected. It is so nice not using 12 tooth pinions any more. The 13 meshes so much better.

I reduced rear spoiler extension with the Peugeot High Downforce (HD) edition body by protoform from .5 to .160 in. I lowered the rear of the body by using my micro adjusting GFR body posts. I lowered the pod to 3 mm. Note it does not sink in the front on bumps like a standard pan. Movement is restricted to up and down by the three link suspension. I lowered the front chassis and made it level at 5 mm. I put on CRC spec tires all around. This changes the purple fronts to a very slightly softer front tire. The goal here is to make the car more stable in the transitions so that I can drive harder in the infield. I'll give a report tomorrow.

Other suggestions for a long flowing layout are welcome.




Gen X 10 build up tips
Tap the holes in the top plate for the 2# x 56TPI ball studs. This will prevent snapping the suckers off.

Your axle may need an additional 1/4 inch ID by 1/32 inch axle spacer between the thrust bearing and the thrust cone to give just a tiny bit more threads. Do not over tighten you diff nut and pull out the threaded stud.

If you are pushing around the track and you have not gone through the front end and made everything move freely well then Duh!
I have a little article on that with a link in this thread not too far back.

There is new molded center pivot hardware available that does away with the messy trimming and shaping of the center pivot plastic. Not too expensive.

I like the extended side plates as they allow a body pin on the shoulder of the car rather than all the way up on the roof. This gives you a stiffer body position.

I like the beefy adjustable long links. These are getting closer in size and length to those that I prefer on my three links. Long links prevent unwanted motion of the pod as it rolls.

The aluminum ball studs on the side links will just not hold up. Get the Losi steel ball nuts. Phil said he had ordered these, but I did not see them on the wall. (Losi JRXS female ball stud; use this term in a search at Stormer)

I like to put a thin hardened steel bellevile washer under the side link ball nuts to distribute the load of the ball nut in a crash and hopefully prevent the corner being torn off. I has seen two bottom plates now broken from tearing out the holes..

back each screw out of the pod and rear of the car about 2 turns. wipe in a bit of blue loctite with your finger. Now retighten. This will prevent screw loss and will still come off later. Note that if any one ever gets stuck you can cut a slot with the Dremmel. The heat will loosen the loctite. A soldering gun works well also. Hold for 20 s until you see light smoke. I see lots of little red screws as I blow off the track.

I attach the lower arms to the reactive caster blocks directly with screws now. I sand the little cones off the ride height shim plates labeled 2, 3, 4. Now I only have to mess with the two big screws to change ride height. You can still change reactive caster blocks without removing the A-arm through the tiny Allen wrench clearance holes provided.
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Old 07-04-2009, 03:30 AM   #914
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John,
Here are some suggestions:

- Remove the rear spoiler extension completely. It makes the Peugeot HD understeer at high speeds. It is slightly understeered without spoiler extension already.
- Increase overall downforce by leaving the part of the body I marked in the attached picture intact. This way you trap more air underneath the body for a better diffuser effect.
Bend these parts outward just a little bit to increase the diffuser effect even more.
- Make sure you open the 2 vents on the front of the rear wing
- Open up the rear panel of the body as much as possible.
- Stiffen the sides of the body with some lexan supports.
- Lower the front of the body to exactly flush with the main chassis. Just in front of rear wheel wells you the body should be flush with the top of the main chassis.
- Lower overall ride height to 4.5mm.

If you need more steering, swap to a Peugeot MD.

If the chassis bottoms out at this height, stiffen up the suspension a bit.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-peugeot%2520905%2520b%2520in%2520908%2520colors%2520resized%2520006.jpg  
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Old 07-04-2009, 03:25 PM   #915
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JJS Pro Ten Track Session, 3 link rear, Double wishbone front wide pan car.

Air temp 103

Mods for flowing high speed track.

So the Sargent asks the private, What is your status private? Blowed up sir! And so it goes with my last test of gearing. 13/87 was working only fair with the new mods. I had too much punch and was spinning out. There was some dust blowing. Motor temps were only 150F or so on the scorching track.

Never have I had so much freedom to tinker with the gearing on a 3.5. Usually you take it to 190F and that's as far as you can go. Sometimes on a lesser motor you just add another tooth to the pinion and the car calms down and becomes smooth. Not so on this 810 Watt, best ever tested, early HV 3.5 monster from Novak. You add another tooth and it just goes faster and gets more punchy. On about the fourth lap, I hear a brrrrrummmmp mid straight at full speed (known only to be well in excess of 64 mph) the rear end lifts and the car slides into the boards. Blowed up. The tire just came off the rim. B4maz has a lot of experience with this. It usually happens on a bump but then starts happening without bumps at about 85 mph plus. I probably hit a little bump, the tire revved up from lack of rear downforce and just blew up when it reached an axle speed of 85mph or so. Man was it fast though.

OK I geared down 1 tooth to 87/13. I added a quarter inch of spoiler back. I put on fresh full size rear tires to gear up just a little. The car was dialed. Radar test tomorrow maybe if conditions are good. We had high winds blowing up some dust today.

People are just wowed by the acceleration of the car when I run it. Now we will see if the lap times are a little better than before.

Here is a photo summary of the changes suggested by Mathijs. Thanks. It's nice to hear from some guys overseas actually not afraid to race these very fast machines.

Photo one shows the blowup of the rear tire in mid session. Never happened to me before. Happened to B4maz's high speed car several times when I accompanied him. He is in the last issue of Popular
Science under High speed RC cars.

Photo two shows the lesser gear protrusion with an 87 and also the LEXAN side stiffeners I added after todays session.

Photo three shows the current wing, it was at 0 extension, but still in place to stiffen that area that becomes very wimpy when you make that cutout below the spoiler. The area under the cutout needed to be stiffened with some LEXAN to flatten the right side bottom which was curved up from influence of the gear bulge.

Photo four shows the front dam even with the bottom of the front of the chassis at 5 mm. I replace the tape strip every session so this is the limit of how low I can go in the front.

Photo five shows the side of the body at full roll just clearing the road.

Novak Early 3.5 HV motor
SMC 6000 mA-h ROAR approved hard case LiPo 28c
LRP TC edition speed control WITHOUT FAN but with duct.
Geared 87/13 full size tire.
CRC Pantoura Chassis
Completely Home designed Suspension.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-blowed-up.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-smaller-spur-side-stiffener.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-compromise-rear-downforce.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-front-splitter-under-car-diffuser-5-mm.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-right-side-body-full-roll.jpg  

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