Forgive me if this has been done already, but I got the idea that it might be interesting to see how the wheels of a rail rider move during a race. To do so, I mounted a camera looking backward on a car in front of the rail rider, started the video and let them both go. It worked... sort of. It needs a lot of improvement. Here's a very sort Youtube video of the results: https://www.youtube.com/watch?v=NmsMPqvbUNQ. Increasing the resolution to 720p sharpens the video a lot. Has anyone else done this and if so, is there a thread on it I can read? Thanks!
Video Taping Wheel Movement
- Thread starter Wayne Schmidt
- Start date
V
Vitamin K
Guest
Wayne, this is Good Stuff(tm)! What would also be great would be if you could film the car from a "standard" viewpoint at the same time, so the behavior of the car down the track could be compared to the close-up view of the wheels.
Just some advice: In looking at the video, it appears that the raised wheel is on the right (looking at the car from the front). The video reveals your lifted wheel is riding the rail. Your speed will increase if you steer into the rail with the FDW and keep the lifted wheel from touching the rail.
Your rear gaps are much larger than I would run, but because of the gaps, it really demonstrates how the rear wheels migrate to the axle heads. Very interesting to see as the car moves around ever so slightly, you can see the left rear moves a bit and then migrates back out to the nail head. You would never see this action at full speed.
Very nice video. Its worth some close scrutiny.
Your rear gaps are much larger than I would run, but because of the gaps, it really demonstrates how the rear wheels migrate to the axle heads. Very interesting to see as the car moves around ever so slightly, you can see the left rear moves a bit and then migrates back out to the nail head. You would never see this action at full speed.
Very nice video. Its worth some close scrutiny.
The car drifting left, so that the raised wheel on the right touched the rail, was a real surprise because on the alignment board the car was set up to drive the left wheel into the rail. The board turn was 2 inches in 8 feet to the left. I'll address this issue before the next video.
V
Vitamin K
Guest
Wayne Schmidt said:
That seems like waaaay too little drift. I usually start at 3-3.5 inches over 4 feet and then tinker from there.
Vitamin K said:
Looking at the design of the cars I don't think he's running near to the COM most of the league racers are, he can probably get by with a lot less steer.
V
Vitamin K
Guest
Momentum Racing said:
So according to some back-of-napkin calculations, a car running a drift of 3" over 4' is turning an approximately 32' circle.
A car running a drift of 2" over 8' is turning a 192' circle.
That's a huge difference, weighting aside, and I suspect it's not enough drift to keep the car up against the rail.
Vitamin K said:
Even without the napkin, this seems to suggest that 2" over 4' would still be nearly three times that of 3" over 4'.
I'm no expert, but given what we saw with 2" and what is generally excepted as a starting point 4", I think I'd try 3" and see what happens.
Given this can be recorded and played back, one could tune to the minimum needed and reduce the drag
Vitamin K said:
I don't think the steer remains linear as the car slows down, what is 4"-4' on a test board I don't think is the same down the hill or along the flat at various speeds.It's hard to say what will work , the car isn't actually going anywhere but against the rail. How much force does a 4"-4 car put against the rail at its max speed, vs as it's crossing the finish line.
I test on a 3' smooth board with a 3' section of Best Track attached to one side as well. I set my steer at around 2" and tune from there, I don't have any cars that would be over 3" on a 4' run.I gain speed on every car I have with less steer, until of course it's not enough and it "looks around" a bit. I remember someone on here saying too much steer will cost you thousands, too little will cost you hundreds, and I agree.
Vitamin K said:
GWebber - Not only is Wayne's car turning only 2", it is only turning 2" in eight feet.
Yes, it could very well benefit from more steering. /images/boards/smilies/thumb.gif
BulldogRacing said:
+1.
I'd also be concerned that the hill isn't dead plumb since the car drifted the wrong way even before it got to the curve.
V
Vitamin K
Guest
Vitamin K said:
For the sake of accuracy, I believe that my circle measurement calculations were for radii, not diameters. So the circle my hypothetical car would follow is 64' in diameter, and the one that Wayne's car would follow would be 384' in diameter. /images/boards/smilies/smile.gif
Wayne....are the rear axles drilled with cant, or did you use bent axles?...could be a rear axle alignment issue in either case.
Have you tried to see if the rears rotate out in reverse, as well as forward?
Also, IMHO it's best not to put the FDW against the rail during staging, I feel placing the wheel against the rail adds to the cars static inertia and acts like a brake that must be overcome.
Have you tried to see if the rears rotate out in reverse, as well as forward?
Also, IMHO it's best not to put the FDW against the rail during staging, I feel placing the wheel against the rail adds to the cars static inertia and acts like a brake that must be overcome.
Just watched the video again. There's audio with it (do not have speakers at work) and you already know the car is drifting the wrong direction. a "duh" moment for me....
