Oil versus graphite on 32 foot wood track.

[Gefecht]

Hello everyone,
I have been utilizing the massive amount of information on this site for the last two years. However there is something that I have not been able to figure out via the search function. My two kids were in Awanas for the last few years. I help them with their cars by doing the the rough carving and power tool parts. Have gotten better each year due to the help on this site. Even broke several track records last year.

My question is this. We are starting to use the max velocity block kits this year. We run on a 32 foot wooden track that is well maintained. I have read in different places that oil is better only on longer tracks. I polish the axles with only a dremel tool and 2500 grit sandpaper. Since the track is only 32feet with a four foot track would it be worth going with oil or stay with graphite? The wheels will be stock, rear wheels canted and my attempt at a rail rider. (I have to drill by eye since I do not have an axle bending tool. And we also run 3 wheels.

Even thoughI use the word I a lot, my children do must of the work. we love learning about the physics and the why of this. Any help you could provide would be great. I will post more details later if needed since I am on my phone.

[gpraceman]

Is oil allowed in your rules? Many prohibit the use of liquid lubes for fear that they will foul the track (graphite fouls a track better than any lube I've seen).

[Gefecht]

Yes, oil is allowed, however after receiving a pm from the expert known as sporty, oil alone is not much if any faster than graphite. Since I am not going to be waxing or polishing the bores. I agree with you on the fact that oil makes much less of a mess than graphite does. This year my daughter wants to go for pure speed. (She was always for design) From what I can figure out, I should cant rear wheels and toe in the from for the DFW. Now, there is not my cant on the DFW correct? We always did it by trial and error while drilling with a dremel and bit. Hoping since the kits from MV are much better than the old Awana kits we used to use, we can break my sons record of 2.47.

Also, one final question if I may. This track seems to not have much of a transition from vertical to horizontal. I was thinking of going from lead to tungsten so I can get my weight smaller and more condensed. Do you think that I have to worry as much about losing energy rotating the mass? Since I am not having to buy the oil. ( I already have MaxV graphite) I am looking to buy tungsten cubes. Is there potential for a faster time due to a small weight area going from lead to tungsten. Also planning on going as thin as I can. Or do most tracks look similar to this?

I apologize for all the questions, but this is my sons last race and my daughters next to last. I also am helping several other children who's parents are unable to help for one reason or another.

[FatSebastian]

Gefecht

Now, there is not my cant on the DFW correct?

Postive camber is recommended on the DFW (anywhere from 2.5 to 7 degrees, depending on who you ask).

Do you think that I have to worry as much about losing energy rotating the mass?

You have nothing to worry about; energy lost by rotating the body on this type of catenary-sag track (formerly made by Piantedosi) is negligibly small.

Is there potential for a faster time due to a small weight area going from lead to tungsten. Also planning on going as thin as I can.

There is the potential to go faster due to the smaller cross-sectional area of a thin body, which will result in lower losses due to aerodynamic drag. Also a slightly lowered center of mass (CoM) might provide some stability benefits. However, you may not see much benefit from a thinner body unless you are first well accomplished with weight distribution, rail-riding technique, and alignment, as these tend to be larger effects.

[Gefecht]

FS,
Thank you for the informative reading. Hopefully, this is my last question. I have been doing everything by eye. We are going to try and make a true rail rider. However I cannot justify the cost for the 2 tools i need to do it. Is there a way to bend them that way without the axle press? I will be using a shim to drill my axles holes at a neg camber for the rear wheels and DFW. However, I keep reading that I should have a bend to provide both the camber as well as the toe in for the DFW. As a reminder, we are using MV axels which are the same as awana axels. (rods)

Once again, thank you very much for all your help.

[FatSebastian]

Is there a way to bend them that way without the axle press?

Sure! In an emergency once, we simply used a spare wheel to hold the axle and slightly bent it by hand.

Preferably, one can secure the pointed end of the nail in something like a bench vise and use a screwdriver as a chisel to gently tap the middle of the nail (at the base where it is secured). Some people will file a groove in the nail where they want it to strike and bend it. (Easy does it!)

I should have a bend to provide both the camber as well as the toe in for the DFW.

Rotation of the bent axle will allow you trade between toe and camber.

[davem]

I have always shimmed the DFW for Rail Riding.
Don't like bending the axles for several reasons.

It takes Patience, and a good supply of wax paper - but you can simply keep adding shims until you get the desired effect w/o bending the axle.

I typically fold wax paper in half, then in half again - so you get the thickness of 4 sheets in one shim.
Create ~10 of these ahead of time.
And keep adding until you get the desired drift.

[Gefecht]

Is there a way to bend them that way without the axle press?

Sure! In an emergency once, we simply used a spare wheel to hold the axle and slightly bent it by hand.

Preferably, one can secure the pointed end of the nail in something like a bench vise and use a screwdriver as a chisel to gently tap the middle of the nail (at the base where it is secured). Some people will file a groove in the nail where they want it to strike and bend it. (Easy does it!)

I should have a bend to provide both the camber as well as the toe in for the DFW.

Rotation of the bent axle will allow you trade between toe and camber.

Question on this, where on the axle should I make the bend? In the middle or where it will be coming out of the body?

[FatSebastian]

In the middle or where it will be coming out of the body?

The latter.

[Gefecht]

Well,
finished the cars tonight. Go figure the race is tomorrow. Have not been able to to anything the last 3 weeks since I have not had a day off of work. Kids did what they could. Figured I would post pics of the finished product. Well, we shall see what happens. Daughter wanted to go for speed. Son wanted design since this is his last year. They are expecting approx 60 entries this year. Hope they do well as they took first in both design and speed last year. We spent 10+ hours geting the wiring working on the el wire and getting it to fit was a challenge to say the least.

[rpcarpe]

Good lookin' cars... interested to see how they do.

[Gefecht]

Well, race has come and gone.
Son did not win anything for design. Then again, not a single one of the 3 cars that won design it was pretty easy to tell that the kids had very little or nothing to do with it. My daughter won speed by a landslide however. 2.260 sec on a 32ft wood track. Closest speed after that was 2.399. I want to say thank you to all the people that helped and everyone that gives information freely on this site. I am thinking of not racing her next year due to all the bad blood that comes into play.

[Stan Pope]

See if you can get the "heat by heat" data for her races and check for glitches ... 2.260 average on a 32' wood track (with Piantedosi dimensions) is unusually fast. OTOH, maybe if they used a laser start gate a bit down track to start the timer the time would make sense. Or maybe the starting line was elevated more than usual.