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Old 04-10-2009, 06:21 AM   #781
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Originally Posted by 2wdrive View Post
dishwashing soap works great. A bucket of handwarm water a spoon or so dishswash soap, chuck te tires in, put a plastig lid or something on the tires so they don't pop out of the water. After an houre or so massage the tires in the soap to get the dirt out, then rinse it with water en massage the soap out. Real easy and quite fast as well.

the first time you apply jack the gripper or something else and whipe it off you almost don't get a dirty ragg or paper, meaning the tires are clean.
The water doesnt hurt the foam? Do you leave them out to dry?
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Old 04-10-2009, 09:20 PM   #782
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The water will not hurt the foam or glue. It takes quite a strong solvent even to attack the glue.

Track Test, Track Sprayer description
light mentioned track prep. I thought I would describe ours.
Firstly our track is 275 x 75 feet. That’s 21000 square feet. 14 dump trucks worth of asphalt.

We use a battery operated sprayer ($600) which our club purchased. Two $80 backpack sprayers would work as good but it takes two men twice the time. It holds 30 gallons. Here is the recipe for pan car.
24 lbs in 30 gallons, or 1 lb for every 850 sq feet. Only spray a 6 foot race line. You don't need to go into every nook and cranny and waste product. You can get by with half of this but then traction will only be medium. 1/8 th scale guys seem to like lower tire wear as their tires are more expensive. I say screw the tire wear give me full traction. Pan cars don't wear the tires very fast. outdoors you can even use full size tires to practice and then half sized tires to race on full sugar.

This sprayer did a poor job at first. It is really a deicing sprayer for parking lots up north. It puts down way to heavy a stream and did not have good coverage. What you need is a fine mist that touches every square inch of your driveline. This is the best way to bind up the dust. If you are putting down drops then there are gaps in between with DUST.
We went to a tractor supply and got insecticide nozzles. I supplied the aluminum beam. Voila, a nice mist 6 foot wide. The middle was just a little dry so I added the hand nozzle to the middle. I tilted the nozzles down slightly to better withstand the wind. It worked absolutely great today. I had sugar down from last Wednesday. It gets covered with dust. Today I just sprayed a coat of hot water. It redissolved the sugar and binds up all the new dust. You can use the same sugar or just a light 2-4 lb batch of sugar to retouch up the track if it has not rained.

In my experience, sprite syrup worked great mixed in water. Rootbeer not so great. Powdered sugar dissolves way fast. That is what we use. All the additives Jeff adds like Karo etc do nothing in my opinion.

The only troubles we have are in cold weather. If the mixture dries too slow (damp cold weather, you saw fog in the morning) then the sugar may crystallize. If it does, make another pass with hot water alone. It needs to be redisolved. There are claims that using some soft drinks will prevent this. I'll believe it when I see fog, cold, sugar with soft drink, and get good results on the first pass. There is always a new winter to try this.

The goal here is a nice non toxic mixture that is environmentally friendly and glues the cars to the dusty track. Don't even think about punishing someone weekly with VHT or methanol.

The surface
Asphalt freshly laid has little rocks imbedded in it that provide texture. Pan car foams need this texture to grip. If you remove the texture completely you will then only expect medium traction. That is what happened at our track. The surface was recoated with a latex product. The only texture is sand that is added by hand to the barrel and mixed in. No little rocks. If you put enough sand the 1/8 th scale guys complain we are getting too much tire wear. Next year you do this all over with and use 1/2 the sand. This kills traction for the pan car. That is our state now, but you can see in the pic there is some construction soon that might restore the texture.

If you recoat the track 3 years in a row you create a new problem that I read about at an asphalt company website and see on our track. The layers do not expand and contract together. They are kind of independent. You just wish there was some bonding going on. Well the top layer cracks (spider cracks) rain water enters. It stays between the layers. When the sun comes out it seeps out for 3 days. This pretty much kills the traction in the area. I think the moral here is not to recoat with a thin layer here unless absolutely necessary. You lose your good original texture. You create the potential for seepage. Instead use sugar water to improve traction if it’s lacking. We are getting a topcoat of virgin asphalt to correct some of these problems. I am really exited about the possibilities for pan cars in the future. It is really expensive now.

I bought a manual sweeper ($300 shipped) for the new asphalt. It has two side brushes axis up, and two wide roller brushes axis horizontal. They counter rotate. It is easy to push. We will use this on the new asphalt to touch the dust and move it, followed by a blower. This may be all we need for a while. It collects a whole lot of dust in the bin.

There is my treatise on track prep.

Pic-I fixed that one dead nozzle after the pic. A tiny leaf was in it.

john
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-sprayer-resized.jpg  
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Last edited by John Stranahan; 04-10-2009 at 10:08 PM.
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Old 04-10-2009, 09:38 PM   #783
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Any chance of getting some pics of your track? It'd be nice to have some mental images to go along with all the testing.
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Old 04-10-2009, 09:49 PM   #784
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Well sure. Go here.

http://www.mikes-hobbyshop.com/OnRoadTrack.html



this is the onroad page at Mikes-HobbyShop.com go here and move your mouse over the photos just for fun.

The new straight will run the entire length instead of having curve before it. If they use my layout it is going to be super nice for our World GT class, the open mod TC class, and the 2010 Nitro Sedan Worlds.
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Last edited by John Stranahan; 04-11-2009 at 07:00 AM.
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Old 04-10-2009, 10:29 PM   #785
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Several new posts above

World GT, Petit Lemans edition, 2s LiPo 10.5

Gearing with temperature

I want to point out a fallacy again that you can gear your car only using the temp gun and get the best performance.

I geared my 10.5 2sLipo Gen X 10 at 24/72. I felt that was the right ratio from seat of the pants feel. The first day I ran it It got up to 98F on the can. Well the weather was cool I wore a coat and the track was slippery. You are just not going to develop much motor temp under those conditions. That does not mean to add 4 teeth until you get some motor temp. You will destroy the good controlled fast acceleration of the car. It will become numb to the throttle.

The second day it got up to all of 110F. I still had poor traction it was a little warmer.

Last session it was 131 F, the track temp was now 110F. I had just below medium traction.

Today I had a motor temp of 159 F. Track temp was cooler 98F, but I had glorious medium traction. There was less wind and dust. The ratio still seems to be spot on. Our track will eventually reach 140F and may have high traction later. I have some cushion, but may end up gearing lower to keep from frying the motor.

anyway don't rely on the temp gun from the guy in Michigan racing outdoors if you are racing in Florida. The real benefit of the temp gun is just to prevent overheating. There is no magic huge power gain when you are frying your stock motor at 210F. What you should be doing is gearing it so it produces maximum power on the track.

More on this stock motor gearing later on the Homemade dyno thread.

Front Diffuser
Opening the area in front of the tires helped the diffuser noticeably. The nose was more glued to the track on the straihgt. I was pleased.
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Old 04-11-2009, 01:03 AM   #786
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I may just have to try the diffuser in the coming weeks. You have a picture of the diffuser on post 756 and when you talk about opening the area in front of the tires, is that shown in that picture below? As prevously mention how I tore off the antenna off my sr3000, I have never seen anything like my car flying in the air now that I am really thinking about it. It must have picked up wind on the bottom and taken off like a plane. So by setting up the diffuser I assume this will help prevent me flying in the air like I did?

http://www.rctech.net/forum/5639490-post756.html
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Old 04-11-2009, 06:54 AM   #787
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Miguel- The post you linked to has the finished diffuser mounted on a Peugeot 905B HD body wide pan car.

This is the mod you are talking about but it is on my World GT narrow pan car with Nissan R34 GTR body. I took the rubbery Associated bumper and cut a curve to the front to match the diffuser and give me a good gap all the way accross. It worked very well last test session above. There is a piece of CRC stiff foam shaped and beveled on top of the front of the bumper. The two pics show the before and after. The left picture worked just Ok. The second picture worked well and kept the nose planted on the straight.

Yes this is to prevent flying into the air; it prevents blowovers.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-diffuser-r34-gtr-resized.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-diffuser-after-cutting-bumper.jpg  
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Old 04-11-2009, 09:14 AM   #788
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The water will not hurt the foam or glue. It takes quite a strong solvent even to attack the glue.
What do you do between races to clean them?
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Old 04-11-2009, 10:16 AM   #789
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I don't clean them at all. I don't go to big races either, though. I would probably just wipe wet Jack the Gripper off with a rag to clean them. Then reapply.
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Old 04-11-2009, 04:33 PM   #790
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Track Test Custom Wide Pan. Independent dual A-arm front end. 3 link rear end.

This is certainly my front end design with the strongest lower A-arms. It should be just as strong as an CRC lower arm by itself. The graphite plate the lower arm is mounted two is a custom part with a very wide base. Two aluminum screws hold the inner and outer lower arm together. The screws may shear before damage occurs to the arm.

The caster setting is rock solid and wont change in a crash.

This is my fastest 2sLiPo electric car by a good margin. When traction is good it is about a second faster than the 3.5 powered TC5 I run.

Today I had medium traction. It would have given the TC5 a very hard time lap time wise. This wide pan was really hooked up.

This is the maiden run of this front end. I previously put a couple of Associated ball stud spacers (thick narrow washers) under each pivot of the lower A-arms (inboard). This more than doubled the travel of the arm. The front end is very supple now and has full travel. Steering was outstanding. I get more steering traction on the sweeper and on the hairpins. Tires were CRC spec rear and GRP (Ghandini) purple fronts. The front end which has a diffuser now as well as a shock remains absolutely glued to the track on the straight. No dancing around at all. Now to CAD this puppy up.

I had some trouble at 2 minutes time, the speed control which is brand new became erratic. A new receiver produced the same problem. So the throttle grew a mind of its own and started dancing around at different speeds (fortunately not full speed but plenty fast) and there I was in the drivers stand with no help. Finally I started making tight donuts near the ditch and then entered the ditch relatively slow where the car accelerated into a stake, stopped and remained still spinning the rears while I could go fetch it. This speed control glitch must of been the source of my early binding problem as well.

John
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-dual-arm-front-end-001.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-dual-arm-front-end-003.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-peugeot-905-b-908-colors-resized-007.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-front-diffuser-peugeot-905-b-hd-002.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-wide-pan-custom-3-link-dual-arm.jpg  

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Old 04-13-2009, 11:56 PM   #791
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Check out this complete brushless motor dyno in the space of an oval chassis. It is based on the Novak Sentry and a Fantom steel flywheel.

Here is a pic
http://www.rctech.net/forum/attachments/electric-road/440936d1239668499-dyno-homemade-using-novak-sentry-data-logger-continued-experimental-thread-novak-sentry-dyno-complete.jpg

Here is where I will start testing some brushless motors.

http://www.rctech.net/forum/electric...ml#post5680266



Attached is a sample output on an LRP X 11 3.5 with the small Nickel plated sintered rotor. This is very realistic of the power output on the track with 2s LiPo.
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CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-lrp-x11-35-nickel-rotor-3-13-09005.jpg  
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Old 04-17-2009, 03:19 AM   #792
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anyone know if corally made foam tires to fit the GenX10?
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Old 04-17-2009, 04:34 AM   #793
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anyone know if corally made foam tires to fit the GenX10?
They will fit, however I have no idea why you would wanna run them...
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Old 04-18-2009, 09:35 AM   #794
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anyone know if corally made foam tires to fit the GenX10?

Yeah they work just fine. Guys around here are running the Goldstar Medium hard fronts, with Gold rears.

Shawn.
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Old 04-18-2009, 01:40 PM   #795
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The water doesnt hurt the foam? Do you leave them out to dry?
it will not hurt the foam. the foam will feel almost like new. I just leave them on the kitchen table to dry. It takes a few houres to dry.
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