Car Specs:
- Exactly 5oz
- .65oz body before adding weight, monkey and canopy
- 3/4 COM
- Drilled canted rear axles
- Rail rider
- .5 Micron polished axles
- Full treatment on wheels (no lightening)
- Krytox lube
- Hydrodipped and cleared
First year Tiger and dad has the derby bug
- Thread starter xtremethings
- Start date
Car Specs:
Nice build! Just covering the hole top & bottom (clear packing tape) probably would have been enough to get you a second. Form over matter is probably your biggest speed loss. There is a wealth of information on this site & any question you ask I guarantee has been asked before. The answers are here! If you get stumped, there are plenty of us here to help out. Your already on the right track by testing.
Good luck!
Good luck!
Welcome.. if your interested in learning more check out my workshop I'm offering. PM if interested
Thanks
Thanks
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Vitamin K
Guest
As far as aero goes, I think the canopy would be the biggest pusher of air...even more so than any voids in the body. Of course, it's a major aesthetic component, so there's that. I do agree that sealing them would be a good idea. Maybe you could cut out some sections from a clear plastic salad-bar clamshell.
Other folks might have a better eye than I, but those wheels definitely look (to me) like they've been turned on the outside. Just an observation.
How did you drill the cant for the rears? Did you use any methods to verify the alignment?
What kind of prep did you do on your wheel bores? What's implied by "full treatment"? Did you apply any kind of wax? Also, did you use an oil-repelling spray (e.g. Jig-a-Loo or Max-Pro) on your axles?
The more details you can give on your build, the more folks here will be able to offer areas to tune for more speed.
Other folks might have a better eye than I, but those wheels definitely look (to me) like they've been turned on the outside. Just an observation.
How did you drill the cant for the rears? Did you use any methods to verify the alignment?
What kind of prep did you do on your wheel bores? What's implied by "full treatment"? Did you apply any kind of wax? Also, did you use an oil-repelling spray (e.g. Jig-a-Loo or Max-Pro) on your axles?
The more details you can give on your build, the more folks here will be able to offer areas to tune for more speed.
I did a ton of internet research and used some close friends in the aerospace industry to come up with a few new ideas. I know the wheels look lathed, but they were taken down to the allowable 1.17" but turning them on a drill press with an iron square and sandpaper. I just didn't spend a ton of time on the outer finish since the inner edges on the rear and outer edge/inner hub on the dominant wheel are the only parts that have contact with the track. As for the bores and outer hub, they were polished and given the liquid glass treatment. The axles were taken to a mirror 60k finish and treated with hydrophobic ceramic nano finish.
The axle holes were press drilled at 2.75 degrees with the use of a 3" Wilton angle vise and alignment was verified via the reverse roll method. It ran with the wheels quickly migrating out and running straight for at least 4'.
I'm hoping to get a few ladder type test cars together like the one pictured and do some testing sometime soon. One car will have the exact setup as my son's car just to see how much the design hurt his time.
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Vitamin K
Guest
I would posit that most of your speed potential is going to be found in your bore/axle prep, and in your alignment.
Are you allowed to use 3rd party axles? If so, you definitely want to do this.
Search the forum for information on "oil process". You could also consider buying access to the premium section of the site which had in depth information here.
You might also search for Lightninboy's posts on verifying alignment. It sounds like you're looking good, but you might want to go a step further.
Finally, I forgot to ask, but I assume you're running a 3-wheeler? Or do your rules require 4 wheels touching?
Are you allowed to use 3rd party axles? If so, you definitely want to do this.
Search the forum for information on "oil process". You could also consider buying access to the premium section of the site which had in depth information here.
You might also search for Lightninboy's posts on verifying alignment. It sounds like you're looking good, but you might want to go a step further.
Finally, I forgot to ask, but I assume you're running a 3-wheeler? Or do your rules require 4 wheels touching?
Must have four wheels, but all don't have to touch the track and no third party axles or wheels can be used. I'm not concerned about that since I seem to be exceeding more than the recommended length of spin and look as good or better than aftermarket axles.
I am premium member, but one thing I don't see a ton of discussion on is that wheels on canted/angled axles don't seem to ride on the entire length of the bore. That means increased loads in very small areas instead of distribution along the entire length. Am I way off with this thought? If not, wouldn't it be better to pay more attention to the contact points and outer hub areas?
I wouldn't mind finishing 3rd with a car that looks that good. That one should be proudly displayed for a long time.
Fine tune your wheel and axle prep at http://npwdrl.com/
Did anyone say move your front wheels back a bit? 4.75" to 5" zone.
Fine tune your wheel and axle prep at http://npwdrl.com/
Did anyone say move your front wheels back a bit? 4.75" to 5" zone.
100 percent cant wheels if you can. Think about the part of the wheel that touches the track. With a canted wheels only a small part of it touches the track.
Thanks for the compliment and is there an advantage to bring the front wheels back a little? Most of the Internet things say the car tracks better with the longest wheelbase, but most of the quicker cars I've seen do have the front wheel back a bit. I guess I'll be throwing another test car together this weekend.
Not sure if there's a better combination, but the car did have a 2.75 degree cant and a 1.5 degree steering axle with a 6" turn over 4ft.
If you have access to a track for testing, you might try running more bend in the front axle? Most guys are in the 6-9 degree range up front. Makes adjusting the drift more touchy though.
If you look at npwdrl pictures on facebook or their website all the fat wheel cars are around 5". There is some variation but not much. And our COM aren't at 3/4" either. There are threads about tape used to hold in the tungsten cubes that allow you to move weight easily or reuse those expensive little buggers.
I will have access to a test track, so I'll try starting at a 6 degree axle and go up from there and see how it works out. I know this is probably a rookie question, but wouldn't the increased angle force the wheel to ride the body harder? Maybe the added friction is just a small trade off to get the wheel to ride on its edge.
If your COM is aggressive enough, there should be very little weight being carried on that front wheel anyway. Having the wheel tipped over reduces the rolling resistance against the rail IMHO.
We've got a 5/8 COM with just under 30 grams on the front dominant wheel. Aside from the rolling resistance against the center rail, what's the best way to minimize body/wheel hub friction? I did apply multiple coats of CA and polish both surfaces that make contact with each other, but I'm not sure if there's a better way out there.
If you can't run washers then what you are doing with the CA glue will work just fine.
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