1st time trying to make a rail rider

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MOFAST
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1st time trying to make a rail rider

Post by MOFAST »

Hi! This is my first post, but have been lurking for awhile. Lots of great information. Does it matter which front wheel you choose to be the rail rider?

The reason I ask is my two sons won 1st in Tigers and 1st in Wolves this past Saturday and are going to district. :) My oldest son's car ran extremely consistent, but youngest son's car has a split in the wood on his left front. There is enough wood there to grab the axle but it won't take alot of handling. We had an old, rough track for our pack race, but District is an aluminum Best track. Just guessing 42 feet. Youngest son won, but barely and it started to flag towards the end of its races. It would break away quickly but cars would gain towards the end of the race. The weight is in the end and the COG is close to the rear wheels. I didn't notice wobbling, of course on our track it would be hard to notice.

I would like to raise that bad wheel but didn't know if it mattered which side. Luckily we are allowed to take cars home between the races and tweak them.
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Re: 1st time trying to make a rail rider

Post by Rukkian »

It really does not matter which wheel is the DFW, other than if the track has imperfections on one side of the rail or the other, but this should not be an issue on the Best track.
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Re: 1st time trying to make a rail rider

Post by john4840 »

I don't believe there is an advantage either way which wheel you make the DFW. We ran cars with on both sides and never had a problem with either side.

John
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Re: 1st time trying to make a rail rider

Post by FatSebastian »

Use the right side when racing in the hemisphere, and the left side in the southern hemisphere. Or maybe I have that backwards. (joke) :mrgreen:
:welcome: MOFAST!
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Re: 1st time trying to make a rail rider

Post by john4840 »

:lol: Nice one
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Re: 1st time trying to make a rail rider

Post by j.m. »

Before you go and change the front wheels around, make sure your rear wheels are going to track right if you switch DFW. You will end up re doing all four wheels. Is the wood repairable? A good quality ca+ hobby glue will fix that split. If the crack is still tight, use the super thin wicking stuff, and if there is a bit of a gap, use the medium gap filling glue. I think I would repair the crack before redoing the whole set-up if you say the car ran pretty true and good.. That's just me though. But to add to the other responses. it makes no difference what front wheel is witch, unless you happen to know for a fact if the track is not level for some reason. Then you almost half to make it one way. Even if you change the DFW, fix that crack, as I can tell you from experiance, yesturday my son's car bouced off the stop foam and smacked into the timer set-up. Then next race, he dropped the car on the floor in transit to the starter. Point is, stuff happens, and if you have a weak link in the car, it could end up ruining your guy's day.
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Re: 1st time trying to make a rail rider

Post by whodathunkit »

FatSebastian wrote:Use the right side when racing in the hemisphere, and the left side in the southern hemisphere. Or maybe I have that backwards. (joke) :mrgreen:
:welcome: MOFAST!

:mrgreen: FS,

It is normal for one or bouth side walls of the best track lanes with the curve
formed in it to be rolled to the center of the lane.
So no matter what side of the car you chose to use as the DFW or drift
into the rail.
It should not affect the function of the track or the speed of the cars
and the fairness of the race.
So why are there fast lanes and slow lanes?
What type of automobile can be spelled the same forwards & backwards?
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Re: 1st time trying to make a rail rider

Post by idpwdnut »

j.m. wrote:Before you go and change the front wheels around, make sure your rear wheels are going to track right if you switch DFW. You will end up re doing all four wheels. Is the wood repairable? A good quality ca+ hobby glue will fix that split. If the crack is still tight, use the super thin wicking stuff, and if there is a bit of a gap, use the medium gap filling glue. I think I would repair the crack before redoing the whole set-up if you say the car ran pretty true and good.. That's just me though. But to add to the other responses. it makes no difference what front wheel is witch, unless you happen to know for a fact if the track is not level for some reason. Then you almost half to make it one way. Even if you change the DFW, fix that crack, as I can tell you from experiance, yesturday my son's car bouced off the stop foam and smacked into the timer set-up. Then next race, he dropped the car on the floor in transit to the starter. Point is, stuff happens, and if you have a weak link in the car, it could end up ruining your guy's day.
Good point j.m. Just make sure wheel is off at that corner as to not get glue in it. Seen that plenty of times.

Visiting a pack race, one car bust out a wood chip at the axle slot on first race. Pack leaders trying to fix it, but had nothing to fix it with, they looked at me, but I was just visiting and didn't have my gear box. Looked at it, looked at the kid, :idea: "Hey kid, give me your gum", he spit it into my hand, stuck it on the bottom to hold the axle in place. He won his den, and placed second overall in the pack. It was a good laugh for us all, but hey it worked :thumbup:

As far as what side the DFW should be on, I put my on the right side. No reason other than I like to hold the car in my left hand and adjust the DFW axle with my right. But maybe FS is on to something with the hemisphere concept. :lol:
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Re: 1st time trying to make a rail rider

Post by MOFAST »

I know it was kind of a silly question, but I am a beginner. Last year we were 2nd to last in the pack, this year two firsts. I am willing to listen and learn. I appreciate everyone's advice.

I had the boys do from 400-600-800-1000-1200-1500-2000-2500-8000 grit on their axles before pack races. For district we are pulling the axles and doing the derby monkey polishing beyond that. Is that enough?

We have done all that we can legally on wheels, none of my mold #s were the "preferred" #'s though. Is it worth buying more wheels trying to get 3s,8s, and so forth?

I think cog or com is good.
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Re: 1st time trying to make a rail rider

Post by Stan Pope »

MOFAST wrote:...
We have done all that we can legally on wheels, none of my mold #s were the "preferred" #'s though. Is it worth buying more wheels trying to get 3s,8s, and so forth?
...
If you are allowed to "do enough to the wheels", almost any of the current crop of wheels will deliver a respectable performance. Key issues of radial and lateral runout and static and dynamic balance can almost always be resolved with permitted treatments. Oversize bores are infrequent, though perfectionists like to search through the wheels for those with the smallest bore diameters to shave a percent or two off of bore friction torque losses.
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Re: 1st time trying to make a rail rider

Post by Speedster »

I'd like to share a story about axles and their preparation since the topic was brought up. Let me start by saying, Yes, I do prepare my axles and I am very meticulous about it.
Two years ago I was working the repair table at our District races. A scout got caught with bent axles (a No-No for our District) and he had to replace his axles to be able to race. He had no spare axles. I told him I had some kits and he was welcome to the axles. His father took the axles and put them in his car in front of me and he passed through the inspection table and his car was then impounded. Nothing was done to the axles. We were using oil at the time, be it Nyoil, 10W30 Valvoline, 80 weight differential grease, whatever. Graphite was illegal at that time. This car went on to take 1st place in his race and I watched him do it. I have no idea what lubrication he had on those wheels. The point here is that the part the axles play in this game is important but is probably not as important as we all think it is. There is a very small part of the axle that is involved in the race. The wheels, however, are a different story.
I'm going to get hammered for this next comment but I'm a big boy. Let the sparks fly. "The friction between the nail and wheel hub remains the same regardless of the diameter of the wheel hub."
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Re: 1st time trying to make a rail rider

Post by Stan Pope »

Speedster wrote:...
I'm going to get hammered for this next comment but I'm a big boy. Let the sparks fly. "The friction between the nail and wheel hub remains the same regardless of the diameter of the wheel hub."
Why should you be hammered? The statement is true.

But it is only 1/3 the story.

The other 2/3 are:

1. The friction (Fn * Cf) is proportional to the normal (perpendicular) force between the hub and axle head, so axles that are aligned "dead on" produce little normal force.

2. The energy loss due to such friction as exists is proportional to the radius at which the hub and axle head touch. This comes from the formula Work (energy) = Force (friction) * Distance. Distance over which the friction acts increases as the friction is farther away from the wheel center.

Got a question though ... All BSA axles (that I've seen) are delivered "pre-bent" and should, therefore be illegal! (The bend is very small, of course.) How does your district cope with that?
Stan
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Re: 1st time trying to make a rail rider

Post by Speedster »

Very Good Question. It is one of those rules that can't be totally enforced. The inspectors are looking for very obvious violations, which the man was in my previous post.
The information you have given me leads me to believe I can build a "legal" Rail Rider under our rules if I look through enough nails. I'll try it. Thank you.
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Bill
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Re: 1st time trying to make a rail rider

Post by Stan Pope »

Speedster wrote:Very Good Question. It is one of those rules that can't be totally enforced. The inspectors are looking for very obvious violations, which the man was in my previous post.
The information you have given me leads me to believe I can build a "legal" Rail Rider under our rules if I look through enough nails. I'll try it. Thank you.
Cheers
Bill
Do your rules also require that the wheels sit "flat" on the track? That is the only reason I can think of for requiring that the axles not be bent.

If you know what kind of toe angle you need and what kind of camber you need, I have a couple of "compute" web pages that will help. See http://www.stanpope.net/driftcomp.htm and http://www.stanpope.net/camdrill.htm.
Stan
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Re: 1st time trying to make a rail rider

Post by Speedster »

Thanks for the info, Mr. Pope. I'm glad I don't have to race you.
I think our rules (lousy and getting worse) are an attempt to make it more fair for a scout who has little or no help. This should be corrected in the Pack. Every year I offer to help anyone who requests it. I am not involved in scouts (please don't scream at me) other than the Pinewood Derby and I'm invited to the Blue and Gold. Each year we get a lot of cars where you can do nothing but shake your head. I think many folks are simply not interested. I showed Dr. Jobe's book to a person once and she said, "That's not the Pinewood Derby!!!!" She actually worked the District races. OK. I'll put my book away. This year our Pack's Activity person violated the rules on building the cars. Did you READ THEM!! It wasn't intentional, I'm sure. She is a wonderful, hardworking person. They filled the axle slots with glue so you could not see the nails, which is illegal. I let him race and told him if he won he would have to clean out the slots. He took second place. How is he going to clean out the slots? The grooves are probably so big they will never hold the nails. I will be curious to see if he shows up at the District Races. No, I can't work with the District pinewood derby leader or the District Executive. They both dislike me intensely. Getting back to the leaders trying to make it "fair" for the scouts. All it has done is make it harder ( ALL FOUR WHEELS MUST TURN) for the scouts. I put that in CAPS because that's the way it is in the rules. This is the 1st year in our District for that rule. The stiff rules have made it easier for the interested scout to win. I wonder if anyone else in the U.S. has to race in this type District. Our foolish rules accomplish nothing but "Dumbing Down the Scouts". A sad situation.
Cheers
Bill
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