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| [GMCnet] Fast Pinewood Derby racers [message #59649] |
Sat, 10 October 2009 17:23  |
Fin Beven
Messages: 101
Registered: September 2005
Karma:
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Senior Member |
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I would like to pass along what I learned from the GMC/Pinewood Derby event, but must give most credit to my son (Charlie), most of what I learned, I learned from watching him while he was in Cub Scouts.
As I remember it, Charlie read an article or ad in "Boys Life" magazine that gave several tips on how to make a fast racer. They have no shape restrictions, just weight. Tons of information about Pinewood Derby can be found on the internet. Just "Google" on Fast Pinewood Derby and you will be amazed by how much information is out there.
My one recommendation to Charlie was based on some observations of what was going on in the sailing world. A guy named Dennis Conner made some huge speed improvements by developing what he called the "two boat" program. The essence was that no matter how hard you try to make two boats identical and equal, one will be faster than the other. When it came to the Pinewood Derby, Charlie attempted to build three identical racers, but it was immediately clear that one was faster than the other two. I still don't know why.
When it came to the event this year, I knew that both Mary and I would have fun in this event. So ... I ordered two GMC kits for each of us. Honest, I did my absolute best to make them all the same.
Here's what I did.
1. Charlie's experience with the Cub Scouts indicated that racers that were heavy in back did the best. So, I use a drill and drilled out a bunch of holes on the under-side between the front and middle axels. My sense is that the more wood you can remove from this area, the better. I also drilled a few holes in front of the front axels.
2. Weight is King. Several Pinewood Derby websites sell what they call "lead wire". It's 3/8' diameter and about 5' long. Very easy to install.
http://www.maximum-velocity.com/speed_supplies.htm#lead<http://www.maximum-velocity.com/speed_supplies.htm#lead>. I drilled three holes in the back of my racer, 3/8" diameter, and about 3" deep, and then just shoved the weights in until I had enough weight be close to the 16 oz. maximum. Because I anticipated that the scales the event would use would not read the same as mine, I left the racer about 1 oz. light. I knew I could always add a bit more weight at the event if I was not up to the limit.
When I added the lead weight to the rear of the racer, I put it down fairly low, thinking that stability may matter most. There is another school-of-thought that weight up high and in the rear may be better. One of the racers in our event just had a big bolt glued to the upper rear. Not exactly pretty, but it did well.
3. Wheels. As required by the rules, I didn't touch them, just installed them. However, there was no requirement that all wheels touch the track. The forward-rear wheels are not needed for speed, so I cut the groove for them just a bit deeper so they don't quite touch the track. With the forward and rear wheels, make sure there is adequate clearance in the wheel-wells for the wheel to spin freely.
4. Long wheel-base is good. That's why I relied on the forward and rear sets of wheels.
5. Axels. Based on recommendations at several of the websites, I put each axel in a drill, and spun it with some very fine emery paper wrapped around the area where the wheels would rotate, just to smooth it out a bit, to polish it.
6. Graphite. Seems absolutely essential. Again, on the various Pinewood Derby web-sites you'll find lots of sources for graphite in convenient squeeze-bottles. The sites strongly suggest applying the graphite and spinning the wheels several times before your race. One site suggested that a good wheel would spin as long as 20 seconds.
7. With the weight in the rear, both rear wheels will set down on the track. There is enough irregularity to the blocks of wood that it is unlikely that both of your front wheels will also touch the track. That's OK, and is basic to one of the Cub Scout speed-tricks. Running on 3 wheels is fast.
8. Smooth shapes. I've seen some pretty odd-ball shapes go fast, so wind-drag may not be among the very important issues, but intuitively, smooth shapes should be faster. I used a belt-sander and good-old hand-sanding to shape my roof and all of the corners similar to the real GMC. It just looks good.
9. Painting Prep. The pine can soak up a lot of paint, so I put on two "sealer" coats of varnish before I started painting, letting each coat dry thoroughly, and sanding between coats. It racer was fairly smooth before I started with the varnish, having been sanded with 320 grit sandpaper.
10. Final painting. We found lots of choices of spray paint at a local hobby store. The brand we used was made by Testors. It seemed to work just fine, and dried fairly fast. We would sand between coats, so that the surface got progressively smoother.
11. The "hollow" in the underside of my racers allowed me to add a few washers, as needed, to bring the racer up to max-weight based on the scales at the event.
12. Feeling really tricky, I covered that under-side hollow area with clear cellophane tape to make the underside smooth.
13. After everything was done, I put a little bit of glue on each axel to make sure they stayed in place.
As I said earlier, I did my darnedest to make four identical racers. Mary and I did a blind draw at home before we started painting. Each of us devised our own painting schemes. I wasn't until we got to Pueblo and actually ran our racers down the track that we had any idea which would be faster. It was obvious in the first race that one of hers had the edge over the other 3.
We each raced our best version. Mary did great in her division, but neither of us could compete with Jim Kanomata. It would seem that he built his in a few hours, just before the race. I knew we were in trouble when it was announced that he had set the track record. He was the best !
We had great fun with this and hope you do too.
Fin Beven
Pasadena, CA
1976 ex-Edgemont, with flames
and ... Pinewood Derby racer, with flames.
----- Original Message -----
From: Ray Swartzendruber<mailto:redruber@gmail.com>
To: 'Bob & Sandra Price'<mailto:bsprice9359@qmail.com> ; 'Bob & Yvonne Miller'<mailto:remiller24@cpinternet.com> ; 'Dan & Ginette Stuckey'<mailto:stuckey@brktel.on.ca> ; 'Emery & Michelle Stora'<mailto:emerystora@mac.com> ; 'Eric & Joanna Tanner'<mailto:jtracinghq@gmail.com> ; 'Fred & Sharon Hudspeth'<mailto:fbhtxak@sbcglobal.net> ; 'George & Carol Baxter'<mailto:glbaxt@aol.com> ; 'Gus & Jane Nottberg'<mailto:gustavn@comcast.net> ; 'J.R. & Jeanne Slaten'<mailto:jrslaten@aol.com> ; 'Jim & Peggy Buchanan'<mailto:chickasaw@charter.net> ; 'Jim Kanomata'<mailto:jimk@appliedairfilters.com> ; 'Ken & Elaine Henderson'<mailto:hend4800@bellsouth.net> ; 'Larry & Margie McLaughlin'<mailto:larryele@nbnet.nb.ca> ; 'Norm & Joan Engman'<mailto:nojoenggmc@yahoo.ca> ; 'Ray Swartzendruber'<mailto:redruber@gmail.com> ; 'Teri Gregg'<mailto:gregg_teri@hotmail.com> ; 'Billy Massey'<mailto:bdub@bdub.net> ; Richard & Jay Hodges<mailto:randjhodges@wmconnect.com> ; Dave & Mary Lenzi<mailto:mlenzi@cha
rter.net> ; Walt & Sara Halley<mailto:we-sshalley@columbus.rr.com> ; 'Fin Beven'<mailto:FinBeven@MSN.com> ; Michael & Irma Bozardt<mailto:ilse@earth-comm.com> ; Carol Swartzendruber<mailto:crdruber@gmail.com>
Sent: Friday, October 09, 2009 5:28 PM
Subject: FW: Dothan Report/Pinewood Derby
GMCMI Board and Others: Following is the report I wrote for Billy to put in the newsletter. Some of your names are mentioned in it so I thought you may like to see an advanced copy{:>) Carol and I are traveling with the Lenzi's and Bolzers's in Nowhere, UT, so we may or may not have internet service, so don't get grumpy if we don't answer you right away.
Have a good one..
Ray (and Carol)
First, a very big thank you to the Western States Club for holding one of their annual rallies in conjunction with the GMCMI rally. Carol and I understand how important they were in making the Pueblo Convention a huge success. The extra seminars, the Saturday dinner, and two extra social events gave added value even to those attendees who were not WS members, but participated in the WS "extras". And our thanks to the Mountainaires for all the extra help in keeping the place clean and orderly, and shuttling people back and forth to the campgrounds. It was quite a hike to the far corners of the campgrounds. Everyone who had toads was very gracious about offering rides to those who did not. Thank you very much for those acts of kindness and consideration for others. GMC'ers are the best.
This convention was among the best we have had. Several people said it was the best ever. The facilities were attractive with lots of trees and landscaping and, in general, very well suited although a bit dated and in need of maintenance in some cases. Weather was good most of the time, a little cool, with very high winds one day. The seminars were excellent, both technical and non-technical. The food was some of the best we have ever had, and everything seemed to go off without a hitch. I cannot say enough about the Hodge's, Engman's, Baxter's, Hudspeth's, Stora's, Slaten's, Jim Buchanan, and others who just grab the bull by the horns and make it happen. The problem with mentioning names is that you always miss someone. My apologies if that someone is you.
Again, the schedule was very full with seminars all morning, and into the afternoon in several cases. Open houses, coach weighing, Emery's Duracool demo, Dave Lenzi's front bearing replacement demo, Red Hat Tea, flea market, and book exchange filled the afternoons. Meals, socials, seminars, Pinewood Derby Races, and Bingo filled the evenings. We are always amazed at how many people take the Bingo very seriously, and don't miss a night. Carol even tried it this time and won $20, so I suppose she too is hooked now.
People were again very generous with donations for the food drive, and the ladies made 64 blankets, all of which were donated to "Compassionate Care" and " The Caring Pregnancy Center", who were very appreciative local charities. Carol took two carfuls to the charities Friday afternoon. That makes 434 blankets the ladies have made since the program's inception. Carol thought the ladies may be getting tired of this program, but they decided to keep doing it at subsequent rallies. Very commendable, I would say. Again, GMC'ers are the best.
We had a maximum of 145 coaches which occurred Monday night, and had a total of 147 different coaches, a few for only a day or so. In addition, we had 11 off site or local registrations. 16 vendors were present, which is down a little from previous conventions, but all were good, quality, supportive suppliers. Many quality items were donated by the vendors to again make the raffle a big success. Thank you very much to all the vendors for your contributions to the GMC community, and to GMCMI. I think it is noteworthy that we had a first time vendor at this convention who sells gas fireplaces/grills. He said "you folks" have a wonderful thing going here, and we would like to be a part of it. This is from a husband and wife team who attend many different conventions. While there, they arranged for his brother to buy a GMC from Michael Bozardt, and they too are looking for a GMC to either replace or complement their SOB. That's quite a testament to our conventions and
camaraderie!
Carol and I try to introduce something a little new or different at each convention. This time it was the Pinewood Derby, thanks to interest generated on the GMCnet forum, and the precedent set by the Great Lakers. By default, since no one else seemed interested in doing it, I made 110 racer kits (including rejects and mistakes), the track, and the timer system, all of which are paid for, thanks to the sale of the cars, a $150 donation by Jim Kanomata, and a $350 donation by the Pacific Cruisers, initiated by Fin Beven. Thank you very much, Fin and Jim, for your enthusiasm, support, and promotion of this event. The hardware and software are now considered property of GMCMI, although no GMCMI funds were used to pay for it!
Walt Halley and his noteworthy team of "experts" actually organized the race and managed its running. We were very worried about participation and lack of interest right up until the time of the race. Once the race started, we had no worries. Many people were there, racers and non racers, hooting and hollering and cheering. The racers ranged from works of art (Fin Bevens), to last minute chunks of wood with wheels (Fred Hudspeth, Laurie Burton). The next morning I sold out of all the racers I had brought along, even the rejects and blem's and 23' models by 10:00 in the morning. I believe there will be at least twice as many participants at Montgomery. Should be great fun. Billy Massey took the track home with him and will set it up for a Classic's rally, and to promote the event for Montgomery. So watch out for the fine tuned racers at Montgomery!!
If you need racers, I think Jim K still has some, but I am out and will have to build another 100 or so soon so you can get them in time to get them ready for Montgomery.
In a closing note, Carol and I have had enough fun putting on these conventions, and feel it is time to let someone else have as much fun{:>) We are resigning effective after the Fall '10 Convention at DuQuoin, IL. It is a paid position ($17,500/year, or 10 cents an hour, whichever is greater) and has some nice perks. So if you are interested please contact us or one of the board members and we will follow up with you.
Regards, Druber
P.S. Sorry this got so long. This was an exceptional convention, and the Derby was a real hoot!
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