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Post by InSuspense on May 12, 2009 19:14:16 GMT -6
Hello All,
I am new to the forum and pinewood racing in general (about 2 months now). My daughter and I were involved in an Awana race in March at our church, and I was hooked. The car we built had a cantilever suspension system that I later saw detailed on Chuck Borough's site (goaskgrandpa.com). My experience to date with this setup has been disappointing, because the flex cars I have built just cannot compete with the simple rigid designs. I have not given up on this flex design however, and I have come up with some designs I would like to try. I do not want to send these cars in to race if they are not allowed because of the subjectivity of the "no springs" rule. Can someone who runs the races please give me some solid feedback on this? Thanks for the help.
-Chris
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Post by fatdaddy on May 12, 2009 19:31:58 GMT -6
My guess would be they are not allowed, as most classes I have seen say no springs, even the extreme pro mod class
3. The following items are PROHIBITED:
A. Springs
B. Starting devices or propellants
C. Electronic or lighting devices that interfere with the race electronics.
D. Liquids, wet paint, oil, sticky substance, or powders of any kind (other than axle lubrication)
E. Glass or excessively fragile parts
F. Loose objects on car
G. Magnets
H. No part of any car, or attachment to any car, that is metal, pointed, sharp, and/or jagged may be capable of contacting any part of the track
I would let you send it in to race, just to see how you ran, and not charge you since there were no classes, but you may be better off finding someone local with a track to test your designs, and save on the shipping. If it's allowed in your race, I say keep trying, you may stumble into something.
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Post by InSuspense on May 12, 2009 20:02:53 GMT -6
Fatdaddy-
Is there a written definition of what is considered a spring, or is it just up for interpretation? This is a bit frustrating as the rules seem different wherever you look.
Do you know specifically if the car would be allowed in the Bluegrass Nationals?
-Chris
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Post by steepslope on May 12, 2009 20:31:30 GMT -6
Fatdaddy- Is there a written definition of what is considered a spring, or is it just up for interpretation? This is a bit frustrating as the rules seem different wherever you look. Do you know specifically if the car would be allowed in the Bluegrass Nationals? -Chris tip, First, welcome to the board. Second, Lucky 13 and Mr. Slick will see this post soon enough and provide you with a definitive answer on what constitutes a spring. I have not been around long enough to be able to answer. I do know that if the car can't run here it can't run Bluegrass because BGN uses PWDR rules. steepslope24 |
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Post by Lucky 13 on May 12, 2009 20:35:41 GMT -6
Fatdaddy- Is there a written definition of what is considered a spring, or is it just up for interpretation? This is a bit frustrating as the rules seem different wherever you look. Do you know specifically if the car would be allowed in the Bluegrass Nationals? -Chris Chris, Spring: a metal elastic device that returns to its shape or position when pushed or pulled or pressed; "the spring was broken" I think the rule regarding "springs" has more to do with an actual "spring". Basically something that could be used to "launch" a car. Your cars are the "flex frame" cars, which means the wood body is cut to flex. Personally, I wouldn't consider it to be a spring. I believe your car(s) would be legal to race. Warren is the "rules" guy and will have the final say, hopefully he will jump in on this conversation. |
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Post by fatdaddy on May 12, 2009 21:18:46 GMT -6
Good call, Lucky, I didn't think of that. Sorry I didn't check that website first, tip, you should be good, but Warren will let you know for sure, welcome to the board!
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Post by ProQuest on May 12, 2009 22:17:46 GMT -6
Fatdaddy- Is there a written definition of what is considered a spring, or is it just up for interpretation? This is a bit frustrating as the rules seem different wherever you look. Do you know specifically if the car would be allowed in the Bluegrass Nationals? -Chris Chris, Spring: a metal elastic device that returns to its shape or position when pushed or pulled or pressed; "the spring was broken" I think the rule regarding "springs" has more to do with an actual "spring". Basically something that could be used to "launch" a car. Your cars are the "flex frame" cars, which means the wood body is cut to flex. Personally, I wouldn't consider it to be a spring. I believe your car(s) would be legal to race. Warren is the "rules" guy and will have the final say, hopefully he will jump in on this conversation. I concur. The rule prohibiting springs did not contemplate a one-piece flex frame that consists of a single piece of wood cut in such a way as to give or flex in response to certain forces. If I am not mistaken a car with a flex frame ran at WIRL a few years ago. Such designs should be legal under our rules. Doc Jobe might be able to shed light on whether such a design has any advantages over the more conventional rigid frame. But whether it has any advantage or not, I say let it run. Steve H. |
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Post by CycRunner on May 13, 2009 0:02:05 GMT -6
In "goaskgrandpa" the premise behind the flex body design, I believe, is to allow the car body to absorb any roughness in the track, which tends to slow down the car. With modern tracks and their very smooth surfaces there is little if any advantage to the flex design. I have also built a flex car and it wasn't any faster than my other cars. I have a very smooth 39 foot track so the flex design wasn't an advantage. As far a being legal I can't see it being classed as a spring design. Even though the car flexes I don't believe the car sould be declared to have "springs", in my opinion. I think it would be interesting to see how the flex design performs in proxy racing.
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Post by ProQuest on May 13, 2009 7:13:36 GMT -6
Cycrunner makes a great point. The advantage really depends on the track.
Think about competitive cyclists. The sprint bikers use bikes with very rigid frames -- they want as stiff a frame as possible. Contests on rough terrain use bikes with some flex -- or even a shock absorber. Hey Ian (Goatboy) hope you will correct me if I am wrong.
Regardless, the flex frame is not a spring, and is not outlawed here at PWDR.
Just a thought.
Steve
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Post by InSuspense on May 13, 2009 8:42:47 GMT -6
Guys, Thanks for all the quick replies and welcoming words. I need to be sure we are all on the same page, so I am posting a picture of the first car we built. It is basically the flex design with the weight installed in the upper body. The attachment point is the same place that the weight is mounted on goaskgrandpa. This is the type design I am specifically speaking of in my previous post. Later I will post a pic of the underside of the car (not on the right computer now).  |
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Post by Mr. Slick on May 13, 2009 9:07:22 GMT -6
A flex frame - strange cut wood body - seems like with Lester's cuts we have several with "advanced" frame designs.
We would allow the style that you describe. As was pointed out, it would have been a benefit in "grampa's time" of wooden tracks and the rough surfaces after a few years of no care. . . with the aluminum tracks and especially the league tracks, there is very little, if any bump to the track.
The flex frame will cause a loss of energy at the transition since force will be taken up by the deformation of the frame as the weight to continues it's fall rather then having to change into kinetic energy. The flex of the frame will reflect lost kinetic energy. . . not a desired outcome.
From my understanding, on the bike side of the world, the rigid frame is to prevent flex in the "drive train" section, even in the bikes with suspension. Any flex of the frame/compression/twist between the pedals and the point of contact with the road is LOST energy. Pedal Arm, Sprocket flex, chain strength, cluster attachment, spoke flex, tire deformation(think of those dragster tires scrunching up), and slip/traction on the road surface. . . the less energy loss due to deformation/heat/slippage the better the outcome.
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Post by Da Pine Racing on May 13, 2009 10:28:53 GMT -6
A flex frame - strange cut wood body - seems like with Lester's cuts we have several with "advanced" frame designs. The flex frame will cause a loss of energy at the transition since force will be taken up by the deformation of the frame as the weight to continues it's fall rather then having to change into kinetic energy. The flex of the frame will reflect lost kinetic energy. . . not a desired outcome. From my understanding, on the bike side of the world, the rigid frame is to prevent flex in the "drive train" section, even in the bikes with suspension. Any flex of the frame/compression/twist between the pedals and the point of contact with the road is LOST energy. Pedal Arm, Sprocket flex, chain strength, cluster attachment, spoke flex, tire deformation(think of those dragster tires scrunching up), and slip/traction on the road surface. . . the less energy loss due to deformation/heat/slippage the better the outcome. Chris, 2 or 3 years ago I built a 1/16" thick body limited car "Try Wait", (this car did pass tech) thinking the flex would help it in the curve and tried different tuning experiments on this car. The most substantial speed gain occurred when I added wood to the bottom of the car to make it more rigid. Mr Slick hit the nail on the head. The flexing will make the car lose energy. Da Pine |
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Post by InSuspense on May 13, 2009 14:18:08 GMT -6
Da Pine-
You wouldn't happen to have a picture of "Try Wait" you could post, do you?
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Post by InSuspense on May 13, 2009 14:37:24 GMT -6
Here is the underside of said car. Pretty basic stuff, I know. By the way, this car came in third out of ten in a very laid back Awana race. I really had no idea at that point how important alignment,wheel, and axle prep were. I have since been enlightened on the topic. Honestly, I am not sure why I am so hung up on this idea. I understand this suspension idea is a long shot, but I have to prove it to myself. Any and all insight you pros can give will be helpful. Thanks again. -Chris  |
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Post by fatdaddy on May 13, 2009 15:10:45 GMT -6
Put the new knowledge you have to work, apply it to the flex frame, and send it in. Once you see how it runs against others, you can make a better judgement on if you want to continue running that style of design or not.
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