How much faster is a RR

[Speedster]

Please give me your opinions.
My young friend, Josh, took second place in his District race 2 days ago. The final track consisted of 8 cars racing for the trophies. There was a method of scoring on the final track that involved points.
The fastest car I own, a 3 wheeler, could beat Josh's car, a 4 wheeler, by about 3". Both these cars run straight.
Here's what happened. The 1st place car, which looked something like a straight piece of sausage cut length ways, would consistently beat us by a full car length. The next 3 cars, one of which we were, would run in a pack. The remaining 4 cars would trail a couple of inches behind us. There was no wood sticking out behind the rear wheels of the 1st place car. If this had been moved to the front, I do not know.
Our rules are, axles may be sanded to remove ridges, wheels may be lightly sanded to true the wheel, no tilting axles, wheels must be setting straight up and down, and all 4 wheels must turn when rolled on a flat surface. Lubrication is Graphite only. This is our 1st year for "all 4 wheels must turn" and the inspectors did check that particular item. The inspectors were not hard nosed on the other rules but the cars that were impounded after inspection looked like everyone tried to obey the rules. Let's just guess that everyone had "Lightly" sanded their axles to perfection and "Lightly" sanded their wheels to perfection. We were racing on a beautiful 42' aluminum track, not a Best track. The track happens to belong to a Pack that a friend of mine belongs to and they take a lot of care in making sure it is level. Our car weighed 141.75 grams, CG 1" in front of the rear axle slot, rear wood moved to the front, and a design I have had a lot of luck with over the years.
Is it possible this young man was able to build somewhat of a rail rider that would pass inspection? Would an "All Out" RR built by a super professional be that much faster than everyone else?
We're looking forward to meeting this young scout again next year. It would be nice if we're not 7" behind him again.
All recommendations very welcome.
Cheers
Speedster

[Eracer]

It is very plausible with a slight toe in of the front dominate wheel and slight camber of the axle but wheel surface still touching the track (4 wheel rail rider) along with a more aggressive and lower weight placement to run ahead of the others as you described. Also a little better axle and wheel bore prep goes along with this.

You mention your car (and your fast 3 wheeler) are straight runners. Even a straight runner is going to contact the rail occasionally during a run, scrubbing time with each hit. A well prepared 4 wheel rail rider with an agressive COM can out pace a similarly prepared straight runner with a 1" COM.

[pgosselin]

Yes, it is possible to build a 4-wheeler that is also a rail rider and would pass inspection. Sporty, one of the moderators of the board, and his kids did it and set track records.

While wheel and axle prep certainly added to the scout's win, the jump he got on you all off the hill seems to indicate his COM was better than yours. I bet his COM was 5/8" to 3/4" in front of the rear axle. That, more than anything else, probably allowed him to grab the lead. Then his axle/wheel prep and alignment allowed him to keep it.

Just my guess.

Paul

[Speedster]

Thank you for your suggestions.
The 1st track we encounter is a Best track. I was told it is 29' between the start and the timer. I don't know if that's relevant in anyway but I thought I'd mention it.
If we set the car up with a 5/8" COM, is it going to handle that quick curve OK?
A friend of mine finished racing 2 years ago. He had won our District races 4 out of the 5 years. He told me it was best to have the cars run straight because of the rough tracks our District had at the time. He finally revealed to me he had been running Rail Riders all the time. What a liar!!!! We both laughed. I'm going to use his car design next year. Maybe it will give me an edge. This will be my 1st Rail Rider.
I'm familiar with Mr. Sporty. He has, in fact, explained to me exactly how to set up a 4 wheel Rail rider. The car is presently under construction. I'm fortunate to have a track with a timer that shows elapsed time. I'll know soon enough if I'm any good at building a Rail Rider.

[Noskills]

I have seen rules where they ask that the wheels are flat on the track. I would think that toe-in on the DFW (with minimal to no camber) would cause a RR effect and follow this rule. Also, I think that a 1-2 degree camber of the rear wheels would cause the wheels to move out to the axel heads and would not look "bent" to the naked eye. The wheels would roll in the test you describe and you would only be able to see the camber if you got on down to car level and looked under the wheels. This is my impression with my limited experience.

Noskills

[Stan Pope]

A few years ago, one of mine made a good 3-wheel straight runner that was 2nd behind the pack winner by about 1".

He built another 3-wheeler with some DFW toe-in, no DFW positive camber, and rear wheels off the rail on level axles that whumped his pack car by 5". (All comparisons on good 4-section Piantedosi wood tracks.) So, yes, RR works without tilting the wheels!

Had the comparisons been made on a 42' track instead of 28', the difference could easily have been 7".

Had all 4 wheels rolled on all of the cars (and were all properly aligned), the results would not have changed.

Guess which one he entered in the district races!