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Thread: Choice of body thickness

  1. #1
    Join Date
    Oct 2008
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    79

    Choice of body thickness

    Hello again,
    Can someone please explain why is it prefered to race .007 thick bodies versus the .010? Thank You.
    Alvin B.

  2. #2
    Join Date
    Jan 2005
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    Used to be Keystone, PA
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    Well,the current theory is that the thinner shell is lighter and therefore a lower CG and more flexible so as not to restrict chassis movement . How ever I see several holes in that line of thought, first is that if the chassis is a single pan design, then movement cannot be restricted by the body so I see no advantage other than a minute lowering of the CG, as I see it if the body is so thin and floppy that the slightest pressure distorts it,then any down force generated is taken up by the deflection of the body and not transfered to the chassis and subsequently to the tires therefore adding nothing to the performance. In the states it seems that we reinforce the body around the wing area, which does add a little weight, the Europeans seem to run the body as is but seem to have more trouble with sucking the body into the gear. When you start with .007 plastic the actual thickness of the shell ends up being much less in some sections of the shell , worse with the .005 material, I have recently had some shells that were so thin at spots that they couldn't even be painted or cut out so I prefer a slightly thicker body, or at least one that is pulled evenly. I expect that someone will disagree with this, but this is my opinion,or maybe I wasted 6 years in engineering school.
    Improving performance one hazardous material at a time.

  3. #3
    Join Date
    May 2003
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    Great Valley,NY
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    .007 body is lighter than .010
    Lower CG=Better handling car.

    If you just want something to beat and bang with, .010 will be more durable than .007

  4. #4
    Join Date
    Oct 2008
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    La Cucaracha, This is what I don't understand. Is it that thin of a line between beating and banging versus racing that the .010 can't or shouldn't be used in racing?
    Alvin B.

  5. #5
    Join Date
    Nov 2007
    Location
    Umatilla, Fl
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    .007 bodies CAN be lighter and more flexible. This depends on the painter, taper and mounter of the body.

    The idea of the .007 body is to provide less mass higher up on the car. I have actually seen a .010 body handle better as there is less distortion of the high downforce features on the body.

    Obviously, .007 is not as durable as a .010.

    All I would say is try both of them and decide what works best for you.

    There is no replacement for testing, testing and more testing.
    Florida Slotter, aka Marty Stanley,
    A "Double 60's" Slot Racer
    Killer X Raceways Team Racer

  6. #6
    Join Date
    Jan 2005
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    Used to be Keystone, PA
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    What someone needs to do is to actually weigh two or three of the same design, one pulled in each thickness, trimmed the same, with out paint so some numbers can be generated to demonstrate if all this hoopla is really worth the effort. I would love to do this myself but I don't have the same shell in different thickness, and as the closest track is 2 hours away, and I'm still in the recovery mode a special trip just isn't in the cards right now. But if someone is willing to do this I would greatly appreciate it.
    Improving performance one hazardous material at a time.

  7. #7
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    Nov 2007
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    Steve,

    I would normally raise my hand to do this. However I am currently laid up due to some recent eye surgery.

    The intersting part of all this is that I'm sure there are good points to .007 bodies as well as good points to .010 bodies. I know there is a weight difference of about 2 grams as I have a .007 and a .010 retro body that I have painted the same color at the same time.

    But I'm sure that body mounting location and so many more factors can change the results.

    I know one fact that will never change - marshaling a thin sided body like one of the Bentlee by O/S is a challenge as there is absolutely nothing to grab on to.
    Florida Slotter, aka Marty Stanley,
    A "Double 60's" Slot Racer
    Killer X Raceways Team Racer

  8. #8
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    Jan 2005
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    Used to be Keystone, PA
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    I don't think there is 2 grams difference between .010 and .007 Lexan, using the manufactures data, I calculate that there is 3.7 grams difference per square foot . And we use much less than a sq. ft. in a trimmed body, I pretty much had the numbers already but would just have liked someone else to verify them so other people don't think that I'm just blowin smoke where the sun don't shine. If you're seeing a 2 gram difference then it must be due to paint. It is really easy to spray more paint than you intended to. I have weighed many of my shells pre and post paint, and usually manage to add at most a gram and usually less, but then I have spent a lot of time and wasted a lot lexan learning how to do so. We'll talk about sides of bodies later as I have discovered some things that were unexpected.
    Last edited by SteveDee; 11-02-2010 at 06:46 AM. Reason: re calculate some nubbers and post correct ones
    Improving performance one hazardous material at a time.

  9. #9
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    I have tested the 2 bodies in question both painted with 1 color very lite, cut exactly the same, mounted the same on same car. On the King Track in Dallas the .007 was almost a 1/10th faster, the .010 got more bite and was stuck. I did the testing before a 2 Hour Endurro, to see if it was feasible to go with to more durable body, but alas I choose not to give the speed. I just added bulletproofing in the front and rear and ran the .007. I did not try harder tires to loosen the .010 car up.
    The .007 body will flex more and it lessens the downforce and loosens the car up, usually it will collapse some in straight dumping air and increasing the speed.
    If you are running on anything other than a High Speed King, you would do well to test both cars and have someone race against both before you make your final decision.
    If there is 1 thing I have found in 46 years of playing Toy Cars there are few absolutes, and just because it worked in January doesn't mean it will in July.
    Your testing should include testing both on the Gutter Lanes as well as the Middle, the advantage you gain in the middle may be lost on the Gutter.
    If you cut the .010 lower, use less paint on the sides and run harder tires you might get it up to speed.
    The guys that consistently beat you do a lot of testing and you should too. There is no substitution for Preparation.

  10. #10
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    Home of the 2007 USRA Nats and a pretty fast King Track
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    Recently the difference was demonstrated to me on a flat techinical track with a Eurosport car. The thinner body made a night and day difference in the way the car handled. One only needs to look at what the fast guys are running for bodies.
    There are "Racers" and there are "Talkers".....which one are you?

  11. #11
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    Jan 2005
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    I'm on a roll, don't stop me now. Warning math content!!!! Here we go. Lexan has a density of 1.2g per cc, this is from the GE MSDS. with a little math this works out to 19.8 g/sq-ft for.007 and 23.6g/sq ft for .010. That translates down to .137g/sq in for .007 and .164g/sq in for .010. Estimating that a trimmed body has about 26 sq in of plastic (3.25"x8") that give a gross difference of .68 grams raw weight. (.007/ .137g/sq" x26sq"=3.58g .010/ .164g/sq"x26sq"=4.26g These numbers compare favorably with the actual weights of some shells that I have. Therefore: the difference between the two shells is .426-.358=.68 grams. Is this enough difference to justify the lighter shell, especially in light of the added reinforcement that may be needed? I sure don't know, there are so many variables and then throw in that it so difficult to do two bodies identically as far as paint and mounting,etc that it just comes down to personal choice. I really don't think that there is enough difference to make or break either one. How many time have you seen someone trash a body during a race and still turn the same lap times (or maybe faster). I don't think that the top racers are winning just because of the use a thinner body sure they use them but I'll bet that if someone won a major or two with a .010, how big would the rush be to jump on that bandwagon.
    Improving performance one hazardous material at a time.

  12. #12
    Join Date
    May 2003
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    Quote Originally Posted by SteveDee View Post
    I'm on a roll, don't stop me now. Warning math content!!!! Here we go. Lexan has a density of 1.2g per cc, this is from the GE MSDS. with a little math this works out to 19.8 g/sq-ft for.007 and 23.6g/sq ft for .010. That translates down to .137g/sq in for .007 and .164g/sq in for .010. Estimating that a trimmed body has about 26 sq in of plastic (3.25"x8") that give a gross difference of .68 grams raw weight. (.007/ .137g/sq" x26sq"=3.58g .010/ .164g/sq"x26sq"=4.26g These numbers compare favorably with the actual weights of some shells that I have. Therefore: the difference between the two shells is .426-.358=.68 grams. Is this enough difference to justify the lighter shell, especially in light of the added reinforcement that may be needed? I sure don't know, there are so many variables and then throw in that it so difficult to do two bodies identically as far as paint and mounting,etc that it just comes down to personal choice. I really don't think that there is enough difference to make or break either one. How many time have you seen someone trash a body during a race and still turn the same lap times (or maybe faster). I don't think that the top racers are winning just because of the use a thinner body sure they use them but I'll bet that if someone won a major or two with a .010, how big would the rush be to jump on that bandwagon.
    I don`t care what school you went to or what body you run.
    I will run the lightest body I can find every time.
    Might put a piece of tape here and there, but I will still run the light body.
    Have fun racing slotcars and support your local raceway.

  13. #13
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    I think that some Euro folks are running .005 thick bodies
    Resident Curmudgeon
    "Manta" Ray Price

  14. #14
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    I am sure it makes more difference on a flat track than on a banked king.

  15. #15
    Join Date
    Mar 2010
    Location
    San Jose
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    38
    My opinion on a couple things maybe not factored in here. The biggest variable will be the body style (HD, NASCAR, LMP, etc) itself. An HD style body will be significantly faster than say a NASCAR type. I often use the adage that if the real car was fast the model should be as well. Case in point, Audi vs (recent) Porsche. This doesn't work for vintage bodies though (real McLaren M8 vs real Shadow TI22). Not all bodies are available in multiple thicknesses (I believe that OS and Redfox bodies come in one thickness only?). Sometimes you have to use what you can get.
    Mounting angle, height, CG and CP (center of pressure) can make huge differences in body dynamics. See how the fast guys on your track are mounting their bodies.
    My own preference is to use 0.010 thick bodies when possible (but my local track owner disagrees with me). This is based on my experimentation with bodes from JK that are available in different thicknesses. I've tested both Bentley versions (same car) with little difference between them until you get in a wreck. The 0.007 is lighter but may not hold up over a full race forcing "field" repairs which cost laps. Also, the high stressed (vacuum formed) areas near the wings tend to collapse easier on the thinner bodies costing downforce, cutting tires and requiring body armor.
    Last thing, different brands of the same body/car behave differently. Case in point OS TI22 vs JK TI22. I have both and find the OS makes more downforce but the JK is more popular with my race buddies. Find the class you are planning to race and see what others are using, then test and experiment.

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