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Post by chrisguyw on Oct 10, 2017 22:34:15 GMT -5
Over the next couple of days I will be posting some notes/observations of the cars as noted during the Boxbury round of the 1967 GP of/du Canada proxy. While most of the cars performed very well, there were a few things that I did notice that held some of the cars back from being more competitive, and hopefully some of these observations/tips/suggestions, will help in future builds. I will be providing a few observations on each car over the next few days, but, I would like to start with a build/set up issue that was noticed on several cars.............a twisted or misaligned chassis, or chassis setup that resulted in 1 (or sometimes 2) front wheels being clear of the track. This was evident (to varying degrees) on cars...#5,..#6,..#19,..#36...#7 The following 2 pictures illustrate this issue The first pic. is a front end shot of the #19 car (not picking on anyone here...just the car I took the picture of !!).....this shows the right hand wheel/tire running off the surface of the track. The next pic. shows that with just very light pressure on the right hand tire...the rear left now comes off the track On a rougher surfaced track (plastic) the effects of this set up are largely masked, but, on a smooth wood track, the effects are very noticeable. On corner entry, (depending on which front wheel is off the track) the car rolls/tips and lifts the opposite rear tire (and will not be running perfectly flat on the tire that is touching)...this reduces traction and consistency Exiting a corner (under acceleration) this lack of stability usually manifests itself as "Chatter", (just like untrued tires/ worn out bushings or a flexible drivetrain) and, is also not a hot tip for quick lap times. On the straights the car will exhibit a less than stable nose and will wander. As these cars are:...very light, are narrow, and run on relatively hard tires, they rely (more than most) on the front tires to act as outriggers for stability,.....keeping the front end stable will ensure that the rear tires stay on the track, providing grip and cornering consistency. These cars do not have magnets bolting the rear tires to the track, they do not have 1/24 scale dimensions, nor do they run on sponge tires which allow considerable compression in corners .........they need the front tires to touch !! There are many causes for this chassis situation....... bent as the result of a crash, misalignment in the building process, different sized front tires (one car has these), flimsy floppy front ends not glued/soldered,...and in the case of the Scaley chassis cars.....it is very common for the chassis to be tweaked when installing the body/chassis screws...these must be adjusted to ensure a flat/square chassis. If there are any questions...please give me a shout Cheers Chris Walker
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Post by tomato007 on Oct 11, 2017 0:15:07 GMT -5
Hello Chris, that‘s very interesting! It would be great to hear your comments also about other and especially my car. Best regards Thomas
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Post by David Mitcham on Oct 11, 2017 4:03:06 GMT -5
Hi Chris
Thank you for this insight - at least my car doesn't seem to have this misalignment. Looking forward to hearing how its performance could be improved.
Best Regards
David
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Post by chrisguyw on Oct 11, 2017 18:15:48 GMT -5
Hello again folks, I will start the car specific observations later this evening, but, there is one more set up procedure that many of you use, one which can be significantly improved upon.............. "Using spacers to set the lateral movement of the rear axle, and then setting the crown, eliminating the need for the motor shaft to center the crown via its trough. This is a good technique as it,.....takes lateral pressure off of the motor can bushing, reduces the friction at the motor shaft/crown trough, and allows a more precise setting of the gear lash......all good things. Some of you use spacers on both sides of the car.............. Some use spacers on only one side........ By using spacers between the inner surface of the wheels and the chassis, you are relying on the wheels to stay absolutely stationary on the axle in order to maintain your gear mesh..........which over a long race, let alone a series, rarely happens.........more often than not, the rear wheels do move in/out, (generally out )affecting the mesh, by allowing too much lateral movement. If this outward movement is severe enough, you can easily strip a Crown. I have seen this many many times. In a crash, if the wheels are forced in, the rear axle will bind, with obvious bad results. If you only use spacers on one side of the rear axle, you are only controlling the mesh on one lateral load plane. So.......................a simple solution........If you get in the habit of placing your spacers between the Crown faces , and the inside bushing flanges, you will eliminate any lateral movement of the Crown regardless of how much the rear wheels slip/move, and , greatly minimize the chance of a bound up axle due to a crash. It is bit more time consuming, and you will need a variety of spacer sizes, but it is worth it................virtually all "Eurosport" F1 slotcars (the really fast ones) use this procedure, and have for years. Cheers Chris Walker The following is a pic. of one of the entrants with the spacers between the crown and the bushings !!
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Post by Terry Newsome on Oct 12, 2017 5:37:04 GMT -5
Nice one Chris!
I'm guilty of "outside spacers" although I have used the inside option, but often find the spacing is too restrictive and opt out for the "outer" option,
This is something I must keep in mind for future builds,
Terry
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Post by old23 on Oct 12, 2017 16:27:42 GMT -5
I will admit to being guilty of packing only the "back" side of the crown gear with a spacer....
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Post by chrisguyw on Oct 13, 2017 13:09:52 GMT -5
Gents, I have one more "General build" observation that was evident on a few cars...at least on the ones I could see,...there were a few that I could not see the Crown/pinion contact.
On cars #7, #36, and #23, the pinion was positioned such that it meshed with only about 1/2 of the Crown tooth depth.....pinion needs to be moved towards the Crown in order that it engages the full depth of the Crown teeth..
While this has absolutely no bearing on the short term performance of the car, it does lead to excessive gear wear (both pinion and Crown) so. longterm, it is certainly a performance issue.
The edge of the pinion is by far its weakest structural point, and running the Crown on the pinion edge will cause damage to the pinion ......I can see this starting on a couple of cars. Not an issue for the balance of the proxy, but, at some point the pinion will need to be replaced.
Similarly for the Crown, by not engaging the full depth of the teeth, excessive wear will occur......again no issue short term, but costly over time.
A well adjusted set of gears in these type of cars should be smooth , and last eons.
One car that has this gear setup issue, also has considerable slop in the rear bushings, so much so that when the axle "wiggles" (likely not the best term for this) the Crown can move back and away from the pinion, to the point where only the very tips of the gear teeth are engaging.............I hope it lasts, but, I do have doubts.
If you can ensure that the pinion edge extends past the inside edge of the Crown teeth (a few thou is fine), you will eliminate some potential issues and save a few bucks along the way.
Happy Motoring
Chris Walker
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Post by datto on Oct 21, 2017 11:01:20 GMT -5
Over the next couple of days I will be posting some notes/observations of the cars as noted during the Boxbury round of the 1967 GP of/du Canada proxy. While most of the cars performed very well, there were a few things that I did notice that held some of the cars back from being more competitive, and hopefully some of these observations/tips/suggestions, will help in future builds. I will be providing a few observations on each car over the next few days, but, I would like to start with a build/set up issue that was noticed on several cars.............a twisted or misaligned chassis, or chassis setup that resulted in 1 (or sometimes 2) front wheels being clear of the track. This was evident (to varying degrees) on cars...#5,..#6,..#19,..#36...#7 The following 2 pictures illustrate this issue The first pic. is a front end shot of the #19 car (not picking on anyone here...just the car I took the picture of !!).....this shows the right hand wheel/tire running off the surface of the track. The next pic. shows that with just very light pressure on the right hand tire...the rear left now comes off the track On a rougher surfaced track (plastic) the effects of this set up are largely masked, but, on a smooth wood track, the effects are very noticeable. On corner entry, (depending on which front wheel is off the track) the car rolls/tips and lifts the opposite rear tire (and will not be running perfectly flat on the tire that is touching)...this reduces traction and consistency Exiting a corner (under acceleration) this lack of stability usually manifests itself as "Chatter", (just like untrued tires/ worn out bushings or a flexible drivetrain) and, is also not a hot tip for quick lap times. On the straights the car will exhibit a less than stable nose and will wander. As these cars are:...very light, are narrow, and run on relatively hard tires, they rely (more than most) on the front tires to act as outriggers for stability,.....keeping the front end stable will ensure that the rear tires stay on the track, providing grip and cornering consistency. These cars do not have magnets bolting the rear tires to the track, they do not have 1/24 scale dimensions, nor do they run on sponge tires which allow considerable compression in corners .........they need the front tires to touch !! There are many causes for this chassis situation....... bent as the result of a crash, misalignment in the building process, different sized front tires (one car has these), flimsy floppy front ends not glued/soldered,...and in the case of the Scaley chassis cars.....it is very common for the chassis to be tweaked when installing the body/chassis screws...these must be adjusted to ensure a flat/square chassis. If there are any questions...please give me a shout Cheers Chris Walker I wonder why this has re-appeared. As i said before i thought it was sorted. I'd be tempted to grasp the rear and front wheels and give the whole thing a twist, though Bruce might pop out of the cockpit I will be extra careful next time.
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Post by chrisguyw on Oct 21, 2017 12:50:51 GMT -5
[/quote]I wonder why this has re-appeared. As i said before i thought it was sorted. I'd be tempted to grasp the rear and front wheels and give the whole thing a twist, though Bruce might pop out of the cockpit I will be extra careful next time. [/quote] Hi Marc, The cars have been sent on to the next round, so, I don't have your car handy to give it another look, but, I do believe it was a plastic chassis/pod. Usually on a plastic chassis one of the following causes "twist"........1/ The chassis/body screws have been overly tightened causing a misalignment, 2/ The pod has been similarly tightened, the front end assembly has not been installed squarely (vertically left to right). There are certainly other causes, but not having the car in hand, I can't identify the specific issue with Bruce. However, grabbing and twisting the front/rear wheels is by far from the ideal fix. Plastic has a memory, and any short term (real short) fix will disappear once the chassis returns to its shape (minutes), and, twisting the chassis like this can (often) tweak the rear bushings in their uprights, causing a bind in the rear axle. Cheers Chris Walker
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