I was aligning one of my non-rail rider cars and noticed that as it went down the alignment board it would first curve to the left then four feet down reverse and steer to the right. It almost seemed like it was a speed issue. The wheels wanted it to go left but once the speed built up something took over and made it curve to the right. It's a three wheel car. Any ideas what's going on? Thank you.
Car Turns left then right on alignment board
- Thread starter Wayne Schmidt
- Start date
Sounds like the car is fighting it's self.
Explain the build to us, i.e. how was it drilled, are you using bent axles, stock axles, DFW axle bend, etc... you get the idea. Pictures may help too.
Explain the build to us, i.e. how was it drilled, are you using bent axles, stock axles, DFW axle bend, etc... you get the idea. Pictures may help too.
The car is called Dark Jedi. It's the second car in the following Youtube video: https://www.youtube.com/watch?v=NEK6f33XbWA. I have to warn anyone deciding to watch the video that it was one of the first I made and the narration is delivered in a flat, repetitive monotone that's so boring it's painful. The car is a three-wheeler with an extended wheelbase, lathed wheels from Maximum Velocity, the steering wheel axle is not bent except for whatever minor bend it had from the factory. The axle holes were drilled with a drill press using a precision jig to hold the car to ensure the holes are all parallel to each other. This used to be my fastest car, as mentioned in the video, but it has since been surpassed by many newer cars.
It's aligned on an 8-foot long vinyl covered board with a start gate. For the first four feet it slews to the left 1/2-inch, then straightens and for the final four feet slews to the right 1/2-inch. This is the only car that does this. Alignment is achieved by using the naturally occurring bend almost all axles have to some very small degree. With accurately drilled axle holes this small bend is all I usually need to align the car to run straight. On this car, 1/4 rotation clockwise or counter clockwise results in at most a 2-inch change in it's left or right position at the end of the alignment board.
Thinking it might be an axle drag issue that increases with wheel rotation speed, I made sure all the axles were well lubricated with graphite before alignment. The axles are stock AWANA axles, polished down on a drill press using micromesh through number 12,000 then polished with Monkey Jam. It takes me 15 minutes for one axle.
It's aligned on an 8-foot long vinyl covered board with a start gate. For the first four feet it slews to the left 1/2-inch, then straightens and for the final four feet slews to the right 1/2-inch. This is the only car that does this. Alignment is achieved by using the naturally occurring bend almost all axles have to some very small degree. With accurately drilled axle holes this small bend is all I usually need to align the car to run straight. On this car, 1/4 rotation clockwise or counter clockwise results in at most a 2-inch change in it's left or right position at the end of the alignment board.
Thinking it might be an axle drag issue that increases with wheel rotation speed, I made sure all the axles were well lubricated with graphite before alignment. The axles are stock AWANA axles, polished down on a drill press using micromesh through number 12,000 then polished with Monkey Jam. It takes me 15 minutes for one axle.
Wayne.....when I first started looking into pinewood cars your videos were some of the very first I watched.I always thought the Jedi car was one of the best looking cars I've ever seen./images/boards/smilies/thumb.gif/images/boards/smilies/thumb.gif
Be careful what you watch.. Most of the time it's axles size verse bore size .. Being bore to big and axles diameter too small.. I'm assuming it's a rail rider
JBD RACING
JBD RACING
Bulldog Racing: Thank you! I'm in the process of converting them all to rail riders to increase their speeds.
Momentum Racing: Thanks! Dark Jedi has always been my favorite, though the Scarlet Screamer looks awfully good with that red metal flake finish.
JBD Racing: Dark Jedi is a straight runner. I haven't converted it to rail riding yet. Both the wheels and axles are stock AWANA parts that came with its kit, so I assume they are matched in size.
Momentum Racing: Thanks! Dark Jedi has always been my favorite, though the Scarlet Screamer looks awfully good with that red metal flake finish.
JBD Racing: Dark Jedi is a straight runner. I haven't converted it to rail riding yet. Both the wheels and axles are stock AWANA parts that came with its kit, so I assume they are matched in size.
V
Vitamin K
Guest
Wayne, good to see you interested in Pinewood Derby again!
Your alignment situation has me scratching my head, but I do have a question about the car's behavior: When you do a slow-roll test on the car, do the rear wheels migrate in any particular direction? Also, I'd be curious to see what kind of results you got from swapping the rear wheels/axles (assuming this can be done without too much hassle.)
By the way, have you seen the Box Stock class in NPWDRL? If you're interested in seeing how far box BSA parts can be pushed, it might be of interest to you!
Your alignment situation has me scratching my head, but I do have a question about the car's behavior: When you do a slow-roll test on the car, do the rear wheels migrate in any particular direction? Also, I'd be curious to see what kind of results you got from swapping the rear wheels/axles (assuming this can be done without too much hassle.)
By the way, have you seen the Box Stock class in NPWDRL? If you're interested in seeing how far box BSA parts can be pushed, it might be of interest to you!
Rolling the car back and forth does not cause the rear wheels to drift in or out. I also checked the front wheel and it too tracks straight, it doesn't drift in or out whether the car is pushed forward or backward. I'm lending my track to a local AWANA race Wednesday and will observe the car during an actual run to see if it favors one side of the rail or the other as it goes down the track.
The Box Car Class looks great. Thanks for suggesting it. Unfortunately because I only race AWANA my cars would be illegal. One look at those hinge pin axles and I'd be disqualified.
I wish those two venues would get together so BSA used AWANA axles and AWANA used BSA wheels. The plastic used for the AWANA wheels is so soft it's like trying to polish bubble gum. Worse still, they pick up debris like crazy. After surprisingly few runs they look like sandpaper. But I'm getting off topic. Sorry.
The Box Car Class looks great. Thanks for suggesting it. Unfortunately because I only race AWANA my cars would be illegal. One look at those hinge pin axles and I'd be disqualified.
I wish those two venues would get together so BSA used AWANA axles and AWANA used BSA wheels. The plastic used for the AWANA wheels is so soft it's like trying to polish bubble gum. Worse still, they pick up debris like crazy. After surprisingly few runs they look like sandpaper. But I'm getting off topic. Sorry.
V
Vitamin K
Guest
Wayne Schmidt said:
Interesting indeed. The only thing I can think of is that there's some kind of velocity-induced behavior of the wheel that only happens after a certain speed is exceeded.
Wayne Schmidt said:The Box Car Class looks great. Thanks for suggesting it. Unfortunately because I only race AWANA my cars would be illegal. One look at those hinge pin axles and I'd be disqualified.
Ah, more's the pity. You're aware, I assume of the Awana class at the APR? They do, however, permit some improvements over "stock" wheels.
