Hi folks, wish I had stumbled upon you a couple of months ago!
I could use some guidance/advice.
My son and I built our first car and raced it this past weekend. We won his den and I believe we were on our way to winning the whole pack when disaster hit and the car jumped the track twice, sustaining damage to one of the wheel hubs, the crew chief (me) didn’t pack any spares (lesson learned). The track was about as smooth as a country dirt road. I was able to repair it, but the car was not near as fast afterwards. We wound up finishing 6th in the pack.
We’re going on to the district and I want to make some adjustments to the car based on what I’ve read here the last few days, and want to make sure I’m heading down the right road.
Here are the particulars on the car:
The car was quite fast (comparatively speaking), we won all of our heats by a healthy margin until the crash. The race was elimination, no timer so I don't know how fast it was. However, the car was fishtailing (or snaking?) all the way down the track. I don’t think this is going to cut it at the district.
My original hypothesis was that the car was tail heavy, and this along with the graphite burnished wheel treads is what was making it swerve. Now, after reading here in the forums for the last few days I’m not so sure.
Here are my questions:
I do have access to a track (not the final race track) for testing, though it is not convenient to get to so I won’t be able to do a ton of testing and tuning.
Any advice is greatly appreciated.
By the way my son and I's main hobby is building and flying model airplanes, so this has been pretty fun as well!
Thanks,
Brian
I could use some guidance/advice.
My son and I built our first car and raced it this past weekend. We won his den and I believe we were on our way to winning the whole pack when disaster hit and the car jumped the track twice, sustaining damage to one of the wheel hubs, the crew chief (me) didn’t pack any spares (lesson learned). The track was about as smooth as a country dirt road. I was able to repair it, but the car was not near as fast afterwards. We wound up finishing 6th in the pack.
We’re going on to the district and I want to make some adjustments to the car based on what I’ve read here the last few days, and want to make sure I’m heading down the right road.
Here are the particulars on the car:
- 3 wheel, rail rider. Front right is the dominant wheel
- COG/balance point is at .75” in front of the rear axle.
- Extended wheelbase, 5 5/8
- Axle holes drilled straight with Derby Worx Pro Body Tool
- The rail riding offset (curve) is about 1.5” per 4’
- Stock Wheels and Axles
- Rear axles are 1.5 degrees and wheels towed out slightly
- Wheels bores and hubs polished with Derby Dust bore polishing kit (includes burnishing the bore with graphite)
- Wheel treads polished with 1000 to 5000 paper and then burnished with graphite (this may have been a mistake)
- Wheel gap established with the Derby Dust gap tool
- Axles polished with 800 - 5000 paper and finished with Derby Dust axle polish
- Below are photos of the weight, which is (not sure I’m using the correct terms here): DFW: 20.27g DRW: 53g NDRW: 71.91g
The car was quite fast (comparatively speaking), we won all of our heats by a healthy margin until the crash. The race was elimination, no timer so I don't know how fast it was. However, the car was fishtailing (or snaking?) all the way down the track. I don’t think this is going to cut it at the district.
My original hypothesis was that the car was tail heavy, and this along with the graphite burnished wheel treads is what was making it swerve. Now, after reading here in the forums for the last few days I’m not so sure.
Here are my questions:
- Should I move the weights to the dominant side of the car, to better balance side to side?
- Does the fore /aft balance look good? Or should I attempt to change it?
- The graphite burnished treads on the wheels sure look good, but could that slickness be contributing to the fishtail? Should I clean the graphite off the treads?
- Should I get rid of the tow out in the rear wheels?
- Should I have the car turn into the rail more aggressively (maybe 5" to 6" per 4')?
- Should I shorten the gap between the wheels and the body (I used a gap tool, but it looks like a lot)?
- Should I pull the axles and Pledge them? They are being held in with CA but I can debond it.
I do have access to a track (not the final race track) for testing, though it is not convenient to get to so I won’t be able to do a ton of testing and tuning.
Any advice is greatly appreciated.
By the way my son and I's main hobby is building and flying model airplanes, so this has been pretty fun as well!
Thanks,
Brian
you want to have the same or the most weight on the dominate side of your car that way your car doesn't try to rock toward your non dominate side. Maybe try to smooth the tungsten putty out a lil to make it more flat to make sure it doesn't drag on the center rail anywhere or put it in the gap that is open at the rear of the car.
