From: rjt@softin.lonestar.org (Richard Threlkeld) Subject: Pinewood Derby Date: Wed, 14 Jul 93 00:31:19 CST I promised many moons ago to post a copy of our pinewood derby packet. It is used by several packs in our area and seems to work. We use double elimination by running all the winners until only one remains, then running everyone (with one loss already) until only one remains. The winner of the winners then plays the winner of the losers. If the unbeaten one wins, he is first place. If the other wins, they must run again since they are now tied with one loss each. The third place goes to the one who won the most before losing two. We have a track with 3 lanes. The scoring sheet must be changed for other formats. I will entertain questions, but although I read this area almost daily, I only have time to interact occasionally. Instructions Setup You will need adults to fill the following positions. 2 persons to register cars prior to the race 2 persons to control the "pit area" 1 person to apply graphite to the cars (as needed) 1 person to control the starting gate (and the track) 3 persons to judge 1st, 2nd, and 3rd place 2 persons to keep score 2 persons to award ribbons for categories 1 person to announce 14 You will need the following papers. 14 Checklists detailing each job (one for each adult) 6 Registration Forms (24 Cubs per form) 1 Score Sheet (15 pages) (will run about 81 Cubs) You will need the following furniture and misc. 1 roll masking tape 4 tables (cafeteria style) 1 postal weight meter 7+ chairs (2 registration, 3 judges, 2 scorekeepers) 1 Pinewood Derby race track w/hardware (3 cars/race) 2 large pillows (for the end of the track) 4+ pencils, pens, etc 1 set of streamers or other crowd control line (masking tape) 1 PA system for the announcer 1 spray bottle of cleaner (for track and tables) ? several rags to clean the track and the table of graphite You will need the following awards. ++ One participation ribbon for each Cub 1 each of Best ... ribbons 3 trophies (1 1st, 1 2nd, 1 3rd) The scorekeepers need to talk over their jobs prior to the race. Physical Layout Registration If time permits, the boy can make one or two practice runs on the track. After the practice runs, he needs to register the car. Use the Registration Form to record each car. As each boy presents his car, weigh it and check for any violations of the rules. Specifically, the car must be 5 oz. or less, it must use the kit which was furnished (including the wheels), it must fit within a 2- 3/4" x 7-3/8" box. If the wheels stick out too far, they will interfere with the car in the next lane. If it fails or the boy wishes to add weights to a low-weight car, do not register him yet. If all is OK, write his name and den number in the appropriate area and copy the vehicle number (in the left margin of the Registration Sheet) to two adhesive dots. Put the dots somewhere on the bottom of the car (or anywhere they have a good chance of staying put). He should put his car on a table in order by den (table should already be marked with tape) and leave it there. It may only be removed to race. It must be returned to the table after each race. Neither the Cub nor his parents should touch the car between races. The judging for "Best ..." will be done during the race from the cars on the table. The Race Copy the registration to the ALPHA list of the race forms. Copy both the vehicle/boy number and the boy's name. Try to leave room at the end of each name line for the race results of that race. The race announcer will need to use the Scoring Sheet to announce the next group of boys to queue up for at least 3 races in advance, so the table where the results are to be recorded should be next to the announcer's podium. Both should be near the end of the race tracks so the judges can easily call the placements. At the end of each race, one judge should always call out the number of the first place car, another the second place car, and the last judge should call out the third place car. It is important to listen to them all since a car can be run at the wrong time. Do not assume the remaining car is 3rd! Write a 1, 2, or 3 at the end of the line for the appropriate boy. The 1st place should be copied to the next winner's race (e.g. the winners in an ALPHA race are written to the BETA Scoring Sheet). Run all the winner races first as single elimination. The "losers" are moved to the MU race list. These are also be run as single elimination, since they have all lost one race and must lose only one more to be eliminated. To prevent a Cub from racing another Cub twice, list all the 2nd places to Mu first, then the 3rd places. Watch those at the dividing line for collisions (where they race each other again). It may be best to start from both ends of the form and work toward the middle or to switch methods after about 1/3 of the entries. Make sure the lane position in the next race is not the same as for the current race, if possible. This will distribute each Cub's runs over the available lanes. Always order the cars at the starting gate in the same order as on the Scoring Sheet. As you record them on the race list, look up each boy on the registration list and record his place for the given race. If he is eliminated from the winner's races, put dashes through the remaining winner's race slots. When he loses in the "loser's" race, put dashes through the rest of the slots. This is a vital confirmation of the results of the race list. You can tell an individual how many wins and loses he has had and when they happened. For the winner of the "winner's" races, put a slash through all "loser's" slots except the last one. A slash is a "by" (a "by" means that the boy did not have to run this race). This is usually done to allow someone who was overlooked in the race to continue with the next level, though adhering to the audit procedures should prevent this. If a boy does not show up for a race after two calls by the announcer, mark an "N" (for No-show) on the Scoring Sheet and the Registration Sheet. After each "heat" (e.g. the BETA race), check that every Cub has some mark for that race. Further, make a quick check of the Scoring Sheet against the Registration Form to ensure that the winners and losers were posted correctly. This will eliminate a large number of problems encountered in prior Derby's. Finally, check each judge's sheet of "dots" against the Regsitration Form. Since each boy must lose twice, if the winner of the "winner's" races loses the final race, then he must race that race again. Only one of the other two boys can have been beaten only once, so the other is automatically the 3rd place overall. The other two run for 1st place. Pinewood Derby Jobs I. Registration: before the race check each car for: 1. Weight 5 oz or less (the scale is final) 2. Fits within a 2-3/4" x 7-3/8" box 3. Used original parts (wheels and axles especially) 4. Is recorded on the Registration Form 5. Has two dots with his number on the car II. During the race A. Pit and graphite areas 1. Only Cubs whose names have been called by the announcer may be near the "pit area" (where the cars are kept). No parents may touch the cars after registration. 2. Only the adult at the graphite station may apply graphite to the cars after registration. 3. Cars will be returned to the "pit area" after running. B. Starting Gate of race track 1. Announcer will call out the car numbers prior to releasing any cars. The adult at the starting gate (gatekeeper) will verify that these numbers are on the cars about to be raced. They must also be in the order they were called. 2. The gatekeeper will then release the cars. 3. If excessive graphite accumulates on the track or other problems occur the gatekeeper may call for a time out to fix the problem. If the problem invalidated a race, it will be run again. 4. When the scorekeepers begin auditing after each heat, wipe the track with a cloth. C. Judges 1. One judge will always pick up the first place car, another the second place car, etc. after it cross the finish line. 2. If any judge feels the race was too close to call for his place, then it will be run again with all cars. 3. Each judge will call out the number on the bottom of the car in his hands in order (1st place, 2nd place, then 3rd place). 4. The 2nd and 3rd place judges will remove one of the dots from the car to show that a loss has occurred. The dot will be stuck to a sheet of paper kept by the judge. Hand the sheet to the scorekeepers at the end of each heat. 5. Each judge will hand the car to the a Cub who will return it to the "pit area". D. Scorekeepers Before each heat (up to 5 minutes-less for later races) 1. Scorekeeper 2 checks the Registration Form to ensure that all Cubs have some mark (1, 2, 3, -, N, or /) in the prior heat's column. If one Cub is found with no entry, give him a "by" and promote him to the next level as if he had won at this level. If two or more are found with no entry, run another race. (30 seconds) 2. Check that the Judges' dot sheets correspond to the Scoring Sheets. Scorekeeper 1 calls out the dot numbers for a given judge while scorekeeper 2 checks the Registration Form. Scorekeeper 1 puts a check mark on each dot as it is reconciled with the Registration Form. Any errors can be checked against the Scoring Sheet. After all are checked, return the sheet to the judge. (3 minutes) 3. During the "winner's" heats, as scorekeeper 2 checks the Registration Form, scorekeeper 1 checks the next "loser's" heat to ensure that all Cubs have been copied. He/she then checks the next "winner's" heat. 4. If the last race in the next heat has only one Cub, move the last Cub of the previous race down so that the last two races have only two participants. 5. Show the announcer the Scoring Sheet for the next 3 races (usually 9 boys). (30 seconds) After each race (50 seconds max) 6. Get the race results from each judge and record it in the appropriate place on the Scoring Sheet (scorekeeper 1) and the Registration Form (scorekeeper 2). (20 seconds) 7. Copy the winner to the next "winner's race" (scorekeeper 1), copy the 2nd place to the next available slot in the next "losers race" (until the MU race)(scorekeeper 2), and copy the 3rd place to the last available slot in the next "losers race" (until the MU race)(scorekeeper 2). Make sure you copy the car number and the Cub's name. (15 seconds) 8. Show the announcer the Scoring Sheet for the next race. (15 seconds) E. Announcer 1. At the start of each heat, get the next 3 races (nine boys) from scorekeeper 1 and ask them to get their cars. 2. Keep ahead of the races so that one group of Cubs is getting their cars, one group is applying graphite, and one group is racing. 3. Always announce the numbers of the cars for the current race to allow the gatekeeper starting gate to verify the cars and their order for this race. 4. Remind the Cubs to remain orderly, do not crowd the track, everyone will get to run until he has been eliminated twice, etc. F. Ribbon Awarding Judges 1. For each den, award a blue ribbon for each category. Typical categories are "Most Obviously Made by a Cub Scout", "Most Unusual Design", "Most Attractive", "Sportiest Car", etc. If you see a car that is clearly the best "something", give it a special category. 2. Every car should get some ribbon. Make as many blue ribbons as possible, then fill in with 2nd place ribbons for large dens. The boys will brag about the 1st place in "..." they got and not realize that most cars were 1st in something. 3. Try to award them early, but remember that up to 9 cars will be out of the "pit" at any given time, so go back a couple of times. Car Registration Form Name of Phase 1 Race Place Phase 2 Race Place Scout Den Alpha Beta Gamma Delta Mu Nu Xi Pi Rho ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- 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---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- ---------------------------|-----|----|-----|----|---|----|---|---|---|--------- Scoring Sheet Page 1 ALPHA BETA GAMMA === start here ===== === from Alpha ==== === from Beta ===== the winners of ALPHA the winners of BETA the winners of GAMMA are listed on BETA, are listed on GAMMA, are listed on DELTA, 2nd and 3rd places 2nd and 3rd places 2nd and 3rd places are listed on MU are listed on MU are listed on MU (81 participants) (27 participants) (9 participants) lane 1________________ lane 1________________ lane 1_________________ lane 2________________ lane 2________________ lane 2_________________ lane 3________________ lane 3________________ lane 3_________________ lane 1________________ lane 1________________ lane 1_________________ lane 2________________ lane 2________________ lane 2_________________ lane 3________________ lane 3________________ lane 3_________________ lane 1________________ lane 1________________ lane 1_________________ lane 2________________ lane 2________________ lane 2_________________ lane 3________________ lane 3________________ lane 3_________________ lane 1________________ lane 1________________ lane 1_________________ lane 2________________ lane 2________________ lane 2_________________ lane 3________________ lane 3________________ lane 3_________________ lane 1________________ lane 1________________ lane 2________________ lane 2________________ lane 3________________ lane 3________________ lane 1________________ lane 1________________ lane 2________________ lane 2________________ lane 3________________ lane 3________________ Page 2 ALPHA (Cont) Beta (Cont) lane 1________________ lane 1________________ lane 2________________ lane 2_________________ lane 3________________ lane 3________________ lane 1________________ lane 1________________ lane 2________________ lane 2________________ lane 3________________ lane 3________________ lane 1________________ lane 1________________ lane 2________________ lane 2________________ lane 3________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 3 ALPHA (Cont) lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 4 ALPHA (Cont) lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 5 ALPHA (Cont) lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 6 ALPHA (Cont) lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 7 ALPHA (Cont) lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 8 DELTA PI RHO === from GAMMA ===== === from DELTA ==== === from PI ==== the winners of Delta the winners of PI the winners of RHO are listed on RHO, are listed on RHO, will compete for the 2nd and 3rd places 2nd and 3rd places first place of the go to MU are eliminated PINEWOOD DERBY lane 1________________ lane 1________________ lane 1_______________ lane 2________________ lane 2________________ lane 2_______________ lane 3________________ lane 3________________ lane 3_______________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 9 MU NU XI === from ALPHA ==== === from MU ====== === from NU ====== the winners of MU the winners of NU the winners of XI are listed on NU, are listed on XI, are listed on PI, 2nd and 3rd places 2nd and 3rd places 2nd and 3rd places are eliminated are eliminated are eliminated (all participants (27 participants) (9 participants) minus one) lane 1________________ lane 1________________ lane 1_________________ lane 2________________ lane 2________________ lane 2_________________ lane 3________________ lane 3________________ lane 3_________________ lane 1________________ lane 1________________ lane 1_________________ lane 2________________ lane 2________________ lane 2_________________ lane 3________________ lane 3________________ lane 3_________________ lane 1________________ lane 1________________ lane 1_________________ lane 2________________ lane 2________________ lane 2_________________ lane 3________________ lane 3________________ lane 3_________________ lane 1________________ lane 1________________ lane 1_________________ lane 2________________ lane 2________________ lane 2_________________ lane 3________________ lane 3________________ lane 3_________________ lane 1________________ lane 1________________ lane 2________________ lane 2________________ lane 3________________ lane 3________________ lane 1________________ lane 1________________ lane 2________________ lane 2________________ lane 3________________ lane 3________________ Page 10 MU (Cont) Nu (Cont) lane 1________________ lane 1________________ lane 2________________ lane 2_________________ lane 3________________ lane 3________________ lane 1________________ lane 1________________ lane 2________________ lane 2________________ lane 3________________ lane 3________________ lane 1________________ lane 1________________ lane 2________________ lane 2________________ lane 3________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 11 MU (Cont) lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 12 MU (Cont) lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 13 MU (Cont) lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 14 MU (Cont) lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Page 15 MU (Cont) lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ lane 1________________ lane 2________________ lane 3________________ Path: elna.ethz.ch!scsing.switch.ch!swidir.switch.ch!univ-lyon1.fr!ghost.dsi.unimi.it!batcomputer!nic.hookup.net!paladin.american.edu!howland.reston.ans.net!vixen.cso.uiuc.edu!sdd.hp.com!decwrl!decwrl!concert!bigblue.oit.unc.edu!nutmeg.fammed.unc.edu!AREID From: AREID@med.unc.edu (Alfred Reid) Newsgroups: rec.scouting Subject: PW Derby Software Available via ftp Date: Wed, 19 Jan 1994 14:02:12 Organization: UNC Department of Family Medicine Lines: 24 Message-ID: NNTP-Posting-Host: nutmeg.fammed.unc.edu Summary: Stearns-method PW derby race generator ftpable Keywords: Pinewood Derby, IBM-PC, Stearns, Software X-Newsreader: Trumpet for Windows [Version 1.0 Rev A] Dennis Parker (and several others) have recently posted descriptions of an alternative to the traditional elimination method of running a Pinewood Derby. Dennis was kind enough to mail me the program to generate race tables for a "Stearns-method" Derby and I've made them available for anonymous ftp for any others who are interested. The following files are available from fammed2.fammed.unc.edu (152.2.41.2) in the directory /home/pub (log in as anonymous, use your e-mail address as a password): PINEWOOD TXT 24445 01-19-94 11:54a PW Derby race generator documentation PINEWOOD EXE 75506 01-19-94 11:55a PW Derby race generator (DOS executable) PWD EXE 56310 01-19-94 12:18p PW Derby (self-extracting archive) Happy derbying! Path: elna.ethz.ch!scsing.switch.ch!xlink.net!howland.reston.ans.net!europa.eng.gtefsd.com!uunet!seismo!doug From: doug@seismo.CSS.GOV (Sam R. Carter (carter@enet.hq.ensco.com)) Newsgroups: rec.scouting Subject: Re: Any hints on building Pinewood Derby Cars? Date: 21 Jan 1994 15:46:29 GMT Organization: hq.ensco.com Lines: 61 Distribution: usa Message-ID: <2hotcl$6v3@seismo.CSS.GOV> References: <2hnevhINN134@RA.DEPT.CS.YALE.EDU> NNTP-Posting-Host: beno.css.gov In article <2hnevhINN134@RA.DEPT.CS.YALE.EDU> griest-tom@cs.yale.edu (Tom Griest) writes: >Does anyone know of a site that has information on how to improve >performance of the Pinewood Derby cars? Or - if you just have some >ideas - post them or mail to me and I will provide a summary. > >-Tom >griest@yale.edu IMO, the secret is in the wheels and axles. I have found that the more care one spends on preparing the nails the better the car performs. Here is my "formula for success" ;) - First use a small file to remove the burrs from around the head of the nail. - Next put the nail about 1/4" into the chuck of a drill and get some emory paper. - With the drill running, slide the emory paper back and forth on the shaft of the nail until the shaft looks round and smooth. You may need a magnifying glass to examine the details. - When you are satisfyied with the shaft, take some jeweler's rouge (a gritty powder available at most hobby stores). Mix the rouge with enough water to make a paste about the consistancy of oatmeal. - Apply the paste to a cloth (cheese cloth is best) and polish the axle using the drill and the method described earlier. - Next tackle the wheels. Basically all you have to do here is remove the burr around the edge where the wheels were molded. You can buy a tool from a hobby shop to do this or just use a six-penny nail. You place the wheel on the tool or nail and place the nail in the drill. Then just lightly sand the edge of the wheel to remove the ridge. - When inserting the wheels/nails into the car care must be taken to ensure that the nails are straight and you should use a thick piece of cardboard as a guide to leave enough room between the wheel and the car body for free rolling. I just cut a wedge shaped hole in the cardboard and insert is between the wheel and the car while tapping in the nail. - In my pack, we are allowed to glue the nails in place. I find that a hot glue gun works best for this as it is smooth flowing and quick setting. Finally a note about weights. I think that the weights should be placed toward the back end of the car. I think this works best because the cars are placed on a slanted ramp so the higher the weight is on the car the more potential energy there is for a faster speed at the bottom. I don't have any conclusive proof that this makes a difference, but we are talking about fractions of a second difference in finish times so any little gimmick helps. Well that's my 2 cents worth, Good Derbying!!! Sam Carter *** My opinions are my own, I make and I intend to keep them. *** Sam Carter Sender: usenet@adobe.com (USENET NEWS) Organization: Adobe Systems Incorporated References: <2hnevhINN134@RA.DEPT.CS.YALE.EDU> <2hotcl$6v3@seismo.CSS.GOV> Distribution: usa Date: Fri, 21 Jan 1994 19:02:49 GMT Lines: 25 In article <2hotcl$6v3@seismo.CSS.GOV> doug@seismo.CSS.GOV (Sam R. Carter (carter@enet.hq.ensco.com)) writes: >In article <2hnevhINN134@RA.DEPT.CS.YALE.EDU> griest-tom@cs.yale.edu (Tom Griest) writes: >>Does anyone know of a site that has information on how to improve >>performance of the Pinewood Derby cars? Or - if you just have some >>ideas - post them or mail to me and I will provide a summary. >> > >IMO, the secret is in the wheels and axles. [ good suggestions from Sam Carter deleted ] I would like to second Sam's suggestions. I believe that he, or some other kind soul, posted this last year. I passed it on to my Webelos and they had a great time preening their cars. A warning however! I have seen a "block of wood" straight out of the box beat our packs multi-year champion dads car. Luck is the greatest consistant component of a winning car it would seem. However you run your derby make sure that it is fun, and that many (4+ or more) runs per car are available for each boy. Charles Hoffman, Webelos Den Leader You are not judged by how much you love, choffman@adobe.com but by how much you are loved by others. - G.P. Oz Path: elna.ethz.ch!scsing.switch.ch!xlink.net!howland.reston.ans.net!europa.eng.gtefsd.com!news.umbc.edu!cs.umd.edu!net.usuhs.mil!net.usuhs.mil!not-for-mail From: dobson@net.usuhs.mil (Michael Dobson) Newsgroups: rec.scouting Subject: Re: Any hints on building Pinewood Derby Cars? Date: 21 Jan 1994 15:42:30 -0500 Organization: National Naval Medical Center Lines: 49 Distribution: usa Message-ID: <2hpenm$hgc@net.usuhs.mil> References: <2hnevhINN134@ra.dept.cs.yale.edu> NNTP-Posting-Host: net.usuhs.mil In article <2hnevhINN134@ra.dept.cs.yale.edu>, Tom Griest wrote: >Does anyone know of a site that has information on how to improve >performance of the Pinewood Derby cars? Or - if you just have some >ideas - post them or mail to me and I will provide a summary. > Another response covered most of what to do to the axles and wheels. Other things to do to the wheels and axles. There is sometimes flashing on the inside hub where it will touch the car body. Lightly sand this surface flat with very fine, 400 grit or finer, emory cloth. The axle grooves are often not exactly perpendicular to the car body. If you have a drill press, drill new holes, 5/64" in diam. on 4-1/4" centers, 1/8" up from the car bottom. Shift the wheel base so the rear axle is 5/8" from the back of the car. Keep the wheels and axles out of the car until the night before the race. Use powdered graphite as lubricant when you assemble them, both inside the wheel and on the car body. Tap the axle into the body so there is 1/32" clearance between the wheel hub and car body. Car weight and weight distribution is important. Get the weight of the car as close to 5oz as you can. Bring several small, flat head wood screws to bring the car up to the max weight at check-in time. The weight should be distributed so that most of it is in the rear. The ideal distribution is such that the car will balance on a point 1-1/4" forward of the rear axle. These are the most important factors. Some experts feel that drilling one axle hole at 5/32" instead of 1/8" up from the bottom so that only three wheels touch the track gives an advantage due to reduced friction. Based on some experiments we conducted at a Pack car construction clinic, I tend to agree. Am aerodynamic shape helps some but not as much as the above plus the other wheel axle tips covered in the other response. Mike CM Pack 1071 Olde Mill Disrtict, NCAC >-Tom >griest@yale.edu -- LCDR M. Dobson | NetNews Admin net.usuhs.mil Experimental Hematology Dept | dobson@net.usuhs.mil Armed Forces Radiobiology | Research Institute | I don't have enough rank to speak for DoD Newsgroups: rec.scouting Path: elna.ethz.ch!scsing.switch.ch!xlink.net!howland.reston.ans.net!vixen.cso.uiuc.edu!sdd.hp.com!hpscit.sc.hp.com!cupnews0.cup.hp.com!mintz From: mintz@cup.hp.com (Ken Mintz) Subject: Re: Any hints on building Pinewood Derby Cars? Sender: news@cupnews0.cup.hp.com (News Admin) Message-ID: Date: Sun, 23 Jan 1994 20:49:34 GMT Distribution: usa References: <2hnevhINN134@ra.dept.cs.yale.edu> <2hpenm$hgc@net.usuhs.mil> Nntp-Posting-Host: hpindwy.cup.hp.com Organization: Hewlett-Packard X-Newsreader: TIN [version 1.2 PL0.7] Lines: 71 Tom Griest wrote: > Does anyone know of a site that has information on how to improve > performance of the Pinewood Derby cars? Legions, I'm sure. But beware of ideas that violate your district's rules. Michael Dobson (dobson@net.usuhs.mil) writes: > The axle grooves are often not exactly perpendicular to the car body. If > you have a drill press, drill new holes, 5/64" in diam. on 4-1/4" centers, > 1/8" up from the car bottom. Shift the wheel base so the rear axle is 5/8" > from the back of the car. Our district rules require that we use the pre-cut grooves in the official kit's block (BSA #1622), which, by the way, are on a 4-3/8" center. > Some experts feel that drilling > one axle hole at 5/32" instead of 1/8" up from the bottom so that only > three wheels touch the track gives an advantage due to reduced friction. Our district rules require that all four wheels touch a flat surface. > The weight should be > distributed so that most of it is in the rear. The ideal distribution is > such that the car will balance on a point 1-1/4" forward of the rear axle. I wonder if anyone knows why 1-1/4 inches is so magic. I believe this number comes the Hodge's book, and I suspect it applies only to his "long wheelbase" design, if even that, which centers the wheelbase on the overall car length, unlike the pre-cut grooves in the official kit's block, which are off-center, creating a "long end" and a "short end". I agree that rear weighting should be best. The reason can be explained quite simply: the further back the center of mass, the more time that gravity will have to act on it and accelerate the car down the incline. Of course, the CM should not be behind the rear axle because the car might do a wheelie as it negotiates the curve at the bottom of the incline. And it might be prudent to ensure that the CM is __some__ distance forward of the rear axle in deference to torque around the axle as the car moves through the curve. I must admit that I am unable to quantify that, even when I know the curvature and theoretical velocity at the bottom of the incline. But "1-1/4" seems completely arbitrary (perhaps even in Hodge's design), especially since that advice does not take into account whether we're talking about the long or short end. FYI, the CM on my car (not my son's) came within 1/2" of the rear axle, and the car did not do any wheelies. At least on our track, the curve is very gentle. But a caution about the "rear weight" theory. My car did not perform as expected. Of course, there can be many reasons for that. I agree with most people that wheel characteristics and "dumb luck" (how the car is set up on the track initially) are the major factors in car performance. I usually pay meticulous attention to the wheel characteristics. But I wanted to share one half-baked (if not "raw") idea I have about my car, which has an extreme design where 75% of the car's mass is concentrated into the rear 1-1/8" of the overall length (!). That means that there is very little weight over the front axle. I wonder if that caused too little static friction on the front wheel, causing it to drag instead of turn during the initial moments when the linear inclined forces are translated into rotational forces. Food for thought. -- Ken Mintz Path: elna.ethz.ch!scsing.switch.ch!xlink.net!howland.reston.ans.net!europa.eng.gtefsd.com!uunet!noc.near.net!news.delphi.com!usenet From: LYNNLARSON@delphi.com Newsgroups: rec.scouting Subject: Re: What wood for my Pinewood Derby Car? Date: Sat, 22 Jan 94 09:42:42 EST Organization: Delphi Internet Lines: 5 Message-ID: <940122.34962.LYNNLARSON@delphi.com> References: <1994Jan13.053655.18286@decuk.uvo.dec.com> <2hdsrq$bhg@huey.cc.utexas.edu> <2hemn3$4nr@sugar.NeoSoft.COM> <2hhvn0$3t5@mercury.mcs.com> <2hp8e3$fk7@net.usuhs.mil> NNTP-Posting-Host: delphi.com Basswood would make a good pinewood derby car. Lightweight and easily worked. However, make yourself sure of the derby car regulations. Besides the 5 oz. limit, there may be front/back axle distance limits, width and/or length limits. The "official" Cub Scout pinewood derby car, a block with cuts pre-made for the axles, is probably the easiest to work with.