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Old 10-30-2007, 10:10 PM   #391
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I agree if you're pulling the front wheels there is not much forward traction to be gained by going to foam. No adjustement to the front will improve on that. The loading requirement you talked about may explain something I noticed. The car would cut in aggressivley but then you could see the cornering force build up. The conditions must have been right that day.
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Old 10-31-2007, 06:22 PM   #392
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Etienne-Thanks for the post. I appreciate all input. I don't quite understand that last part of your second post. Do you mean as the loading on the outside tires increased it cornered harder when normally it should do the opposite with weight transfer.

Front Air Dam
What produces most of the front downforce of a car body in motion is the vacuum that is created behind the airdam. This holds either the hood down or the belly pan down on the race car. Additional downforce is created by air hitting the slanted front surface of the body. I had removed most of my dam to run the body really low with the GRP foams. I mounted a Lexan Air Dam with a 2 mm soft dam under it. I found out with experiments with the pan car that tended to fly at speed that this type of soft airdam is very effective. You can get just a little closer to a rough track with a soft electric tape, (strapping tape inner)strip. This all adds some weight to the body so a new body with soft dam would be a better deal.

Lunsford Titanium Hinge Pins.
The stock steel hinge pins weigh only 11 grams so I probably lost about 4 grams. Most of this weight moves or rotates with the A-arms so it is good to remove weight here and put it else where. The pins are .0005 inch (5 ten thousandths) over the stock pins, but they rotated easily in the arms so this removed some slop. You could polish these with 1200 grit sand paper if you like. I am going to let the track do that.

Weight Progress
The scale reading makes it look like I lost progress at 40.6 ounces for the chassis, ( I was just under 40 ounces previously) but I am on rubber tires now which are 2-3 ounces heavier. I removed the front bumper. I am using IRS bidirectional battery tape. On our layout we don't seem to batter the center front much. Mostly a side hit on the boards if you overestimate traction. I ran the pan car without a front bumper for quite a while. The foam front bumper now is a battery spacer block from associated.

Body Reinforcement
Lately I have been using a fiberglass cloth strip (from the aircraft section of the hobby store) and Sobo Premium grade Fabric Glue (pint size from a fabric or craft store). To reinforce the fenders. The body lasts a lot longer this way as usually a fender crack kills them. Coat the body. Lay on the fiberglass, then fill the cloth. This glue dries flexible but slick so it stays a little cleaner than others I have tried. Photo 2
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-front-air-dam-resized.jpg   Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-front-air-dam-bottom-002.jpg  

Last edited by John Stranahan; 11-06-2007 at 08:59 AM.
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Old 10-31-2007, 07:52 PM   #393
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John,

Are you using anything to secure the battery to the chassis other than tape? Does its flat bottom cause it to shift easily, or eject?
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Old 10-31-2007, 08:04 PM   #394
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I know from experience with a TC4 team edition that a heavy Nicad pack will eject with only tape on our track. I have not tested my tape only setup yet. I plan to test tomorrow. My pack is not too heavy so it may be OK. It also just barely fits in the car so it is snug in a couple of places. Several guys do use servo tape to glue battery slot shaped pieces to the bottom of the battery. If it looks like it is shifting around too much I will add these. I don't like this as much as using the battery strap, but I plan to race it this way to have the car as light as possible. I will practice with the normal battery strap setup with the battery taped to the bar.
The stock battery tape slots are in a very good position for this sized battery. Right at the ends.
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Old 10-31-2007, 08:36 PM   #395
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Here is a possible lightweight fix. I used Dubro thick Servo tape (from the aircraft supplies) to make two battery slot sized spacers. This servo tape is extremely sticky. It will hold on to the battery well and keep it well placed side to side.
John
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Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-battery-strap-bottom.jpg  
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Old 10-31-2007, 08:58 PM   #396
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McMaster-Carr has some adhesive-backed plastics in varying thicknesses, all the way up to .06". I may try using something like that down the road if I don't end up using adhesive weights like those from Nexus.

I'm on the bandwagon with those Saehan cells from FMA. After learning my lesson with the first pack, the second one was easy to modify and fit into my car. While the driver (and car) could use some work, I definitely didn't feel underpowered in comparison to the folks running NiMH. I think it helps that we're all running brushless, so those guys are almost always running heavy, while I'm able to sit right at the weight limit, and place weight wherever I'd like for perfect ballast.
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Old 10-31-2007, 09:14 PM   #397
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Syndrome-Thanks for the battery report. I am glad you had good luck with a second pack. This leads me more to believe the first pack had a weak connection. I noticed on your picture of the complete pack that they were a different brand than mine. Are they from FMA direct. Now the trick might be to keep the charge rate reasonable (<1.4C) so they hang on to their specs longer. I'll have some data at 25 cycles soon at a 45 amp discharge.
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Old 10-31-2007, 10:40 PM   #398
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Originally Posted by John Stranahan View Post
Syndrome-Thanks for the battery report. I am glad you had good luck with a second pack. This leads me more to believe the first pack had a weak connection. I noticed on your picture of the complete pack that they were a different brand than mine. Are they from FMA direct. Now the trick might be to keep the charge rate reasonable (<1.4C) so they hang on to their specs longer. I'll have some data at 25 cycles soon at a 45 amp discharge.
John
John,

Yep, they're the 4800's from FMA direct purchased in the last two weeks.
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Old 10-31-2007, 11:30 PM   #399
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Quote:
Originally Posted by John Stranahan View Post
Syndrome-Thanks for the battery report. I am glad you had good luck with a second pack. This leads me more to believe the first pack had a weak connection. I noticed on your picture of the complete pack that they were a different brand than mine. Are they from FMA direct. Now the trick might be to keep the charge rate reasonable (<1.4C) so they hang on to their specs longer. I'll have some data at 25 cycles soon at a 45 amp discharge.
John
OH! That was my assembled pack that I wedged into an old Orion Platinum case and covered in black shrink wrap. I just threw it in there to show the "finished" product. Sorry if that was confusing. When it came out of the package, my pack looked exactly like the one in your pictures, and was as long as you described.
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Old 11-01-2007, 03:57 PM   #400
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Thanks for clearing that up. The Nexus label is what threw me off.

Track test
Track dusty
I finished the tests on Ackerman. I made the final move to the back position on the bellcrank. I noticed no improvement so I went back. The final Ackerman position was forward on the bell crank innner on the steering arms.

Lunsford pins worked great there was no loss of traction that might be caused by binding.

I maded one final move on the rear upper shock mounts. I went in two holes to add steering. Note this is backwards from normal due to the locked diff.
I started to get a little tail out behaviour on the sweeper; the car got a little bit loose (oversteer). I went back out one hole to split the difference.

The IRS battery tape worked great. There was enough sticky to run 3 batteries with the same piece of tape. The foam underneath worked well to keep the packs from moving. The only problem was The foam servo tape stuck to the strapping tape on the bottom of the chassis. I took the paper on the bottom side of the foam servo tape and reversed it (slick side out) to solve the problem. I liked the fact that the tape never split on me due to the cross braid. It is a bit expensive though, but a roll should last a long time if you can keep from loaning it out. I was able to run my smaller pack without any modifications.

So what did removing a few ounces do. Well it was dusty so it was hard to compare exactly. The blazing fast acceleration was moved a few feet farther out of the corners. Some slight throttle feathering was needed initially. This suits the long track well. On race day I predict it will just be faster everywhere.

The second X11 3.5 motor was as fast as the first. Thats good news. Ready to race. I need to check the wheel bearings before the race. This is a bit of a pain, but a broken bearing will cause a DNF.

Prerace Check
I checked the bearings, 4 were usable with new oil. 4 were brinneled from impact with the boards. You check these by inserting a pencil point in the inner race. Spin the bearing in your hand with the pencil. It is easy to feel Brinneling (a racheting action caused by little dents the balls create with an impact) or a dry bearing.
Good thing to check before a race. Also pop the lower shock mount off the ball and make sure the suspensin drops free from gravity alone when you test it.
John

Last edited by John Stranahan; 11-02-2007 at 06:08 AM.
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Old 11-01-2007, 05:50 PM   #401
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Hey John,

just wanted to make a wuick point about removing the bumper....

Doing so, you've removed any support for the front of the shell. This can lead to deformation of the body shell at high speed (much like the reason for inclusion of 5th body posts in some kits) and increase the chance of the front wheel arches cracking in crash as the front tucks under... I also notice you've reduced the spacing between the body posts as well, again reducing the support on the bonnet (hood) area....However, given you've reinforced the front of the shell like you have (with the GRP strips), I doubt you'll see an problems with the shell deforming.

Up until the begining of this year, I had never really paid attention to the spacing of the bumper against the shell, until I had it pointed out by a fellow racer. Now, whenever I mount a new one, I make sure there is minimal gap between the bumper and inside of the shell. Partly I achieve this by body positining, and partly by adding foam strips to the front of the bumper.
Since doing this, I've certainly reduced the amount of wheel arch cracking... although given I race indoors and mainly stock, not really seen the affect of shell deformation.

Just wanted to point that out, thats all.

Keep up the interesting work
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Old 11-01-2007, 06:04 PM   #402
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Try Hard-Thanks for the tips. I agree that using some contact of the front bumper to the body will reinforce it. I also agree that using a bumper on most indoor tracks is a wise choice. I missed that third body post of the JRXS myself. My TC5 bumper did not have this contact. I trimmed it to clear. It is easy for me to hear on the straight when my body is deforming and causing contact with the track. Usually this will not occur until your arches are cracked. The body pins are actually more rigid now that they are attached to the frame itself compared to using the half bumper I tried previously. My body pins are in the same position fore and aft so this problem of nose droop has not occured or worsened. Also my reinforcements help like you mentioned. On our track most impacts are to the side or corner where a bumper does not help. This is an unusual condition for TC, but it is really a long outdoor 1/8 scale track that I run on. I am going to study the lap times and see if this mod was worth anything. The car felt definitely faster Saturday. I don't recommend that you remove your front bumper unless your conditions and goals are similar to mine. Now if I have a collision and the body wads up in the front and makes the car undrivable, I will immediately replace the bumper. This was not the case with the pan car.
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Old 11-02-2007, 04:56 AM   #403
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Quote:
Originally Posted by TryHard View Post
Hey John,

just wanted to make a wuick point about removing the bumper....

Doing so, you've removed any support for the front of the shell. This can lead to deformation of the body shell at high speed (much like the reason for inclusion of 5th body posts in some kits) and increase the chance of the front wheel arches cracking in crash as the front tucks under... I also notice you've reduced the spacing between the body posts as well, again reducing the support on the bonnet (hood) area....However, given you've reinforced the front of the shell like you have (with the GRP strips), I doubt you'll see an problems with the shell deforming.

Up until the begining of this year, I had never really paid attention to the spacing of the bumper against the shell, until I had it pointed out by a fellow racer. Now, whenever I mount a new one, I make sure there is minimal gap between the bumper and inside of the shell. Partly I achieve this by body positining, and partly by adding foam strips to the front of the bumper.
Since doing this, I've certainly reduced the amount of wheel arch cracking... although given I race indoors and mainly stock, not really seen the affect of shell deformation.

Just wanted to point that out, thats all.

Keep up the interesting work
oi get back to ya tamiya toy car thread :P
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Old 11-02-2007, 06:05 AM   #404
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Outdrive Bearings
I had the rear diff out to change belt tension and diff height. The outdrive bearings (10mm x 15mm)were dry and not very smooth. Apparently they are lubed with oil. Normally these bearings, lubed with grease, outlast the kit as they get no high imact loads. You can add oil with the bearing worked with the fingers and get some inside past the seals. I plan to replace these with greased bearings when I find some. The rear diff with Aluminum Oudrives is holding up very well.
John
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Old 11-02-2007, 07:15 AM   #405
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Outdrive Bearings
I had the rear diff out to change belt tension and diff height. The outdrive bearings (10mm x 15mm)were dry and not very smooth. Apparently they are lubed with oil. Normally these bearings, lubed with grease, outlast the kit as they get no high imact loads. You can add oil with the bearing worked with the fingers and get some inside past the seals. I plan to replace these with greased bearings when I find some. The rear diff with Aluminum Oudrives is holding up very well.
John
I think this is becoming the norm with most bearings used in sedans and 1/12 currently. Acer Ceramic bearings are lubed with oil, as are the stock XRay T2 '007 bearings.

XRay had to investigate and post up appendunum regarding the cleaning and re-oiling of bearings with multiple reports of pre-mature bearing failures.

Since you're working on a TC5 (Associated) I don't expect them to mention anything about the care and maintenance of their bearings, as they usually don't include much, if any, setups tips and maintenance. I had a TC5 for a few months and found the smallish 6x10mm wheel bearings to be too small to handle any type of abuse without regular maintenance every 1-2 weeks.
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