Derby Talk

I just ordered the Car Inspection Go/No-Go Gauge from GP and noticed that it's height limit checker is 3". I really didn't worry about it since I hadn't planned on imposing any sort of height restriction in our race (our timer sensor is mounted below the track). However, I just received the rules from our Council and they are imposing a 4" height restriction (I guess due to finish gates).

So, will I negatively impact our Pack's cars by limiting them to 3" (I realize that this might limit some of the design creativity, but I'm thinking about speed/performance here)?

If so, has anyone ever tried modifying the gauge to a different height? It looks like you might be able to fashion an inverted "U" out of sheet metal and install it over the top to allow extra height. Any thoughts on this?

The height checker meets the majority of race rules in use, which limit height to 3". You can simply remove the height checker piece, if your limit is above 3", or modify it as you suggested.

As far as a competitive disadvantage if you go with a 3" limit, I really don't think so. The center of gravity should be low on the car for better stability and more of a pendulum effect. Having a tall car raises that COG and can reduce performance.

Ok, that what I thought as well (about the stability). I've always built pretty low-slung cars.

I think I'll just stick with the 3" restrictions.

dfscott wrote:I just ordered the Car Inspection Go/No-Go Gauge [...] So, will I negatively impact our Pack's cars by limiting them to 3" (I realize that this might limit some of the design creativity, but I'm thinking about speed/performance here)?

I agree with gpraceman that you will not introduce a competitive disadvantage by limiting to 3". If anything you are doing your racers a favor - I suspect that there will be few to no cars going well at Districts that are 4" tall. In addition to the issue that gpraceman raises, aerodynamic drag increases with frontal cross-sectional area: a 5 ounce car body that is ~4" tall could have an order a magnitude more air resistance than a car body that is 3/8" tall.

If one was worried about limiting creativity though, how about a 4"-high hood out of cardstock or posterboard?

For us, we limit by the physical timer we have which is 7". And we do have plenty of kids go for design type awards that push this limit.

We removed the wood spacer from the sizing box, and we tried to a have a u-shaped replacement for a while, but it was always in the way. Instead we have no spacer, but on the car that is clearly pushing past 5-6", we put car on table and turn the meauring box on its side and have a 7" mark made.

If that is close, we go roll it under the timer.


But for speed, I can't remember a pack final that had any cars much (if any) higher than the wheels themselves.

"No limit" is cool, but it can cause some problems.

Our district height rule was set pretty low (3 inches) because we must borrow tracks (at least 4 of them) to hold our district races. The number of high quality tracks is low enough that we must be able to run under almost whatever finish line they have. If we had to decline more than one of those donated tracks, we would be close to out of business. After a survey of resources, we set 3" as the height limit.

We could ignore that limit if we found that the actual track that the racers would run on had higher clearance, but what if they won then they would be on another track in the Race of Champions (track selected by "best quality"). All in all, it just seems better to set a limit and hold to it for district racing and to strongly recommend that units apply the same limit, lest one of their district race representatives be disappointed.

dna1990 wrote:For us, we limit by the physical timer we have which is 7". And we do have plenty of kids go for design type awards that push this limit.

Same here, except our published limit is 5.5". Our finish gate is actually a bit higher than that, but I'd rather have a safety margin. And the design-oriented cars that push the height limit are never competitive in the race.

Darin McGrew wrote:

dna1990 wrote:For us, we limit by the physical timer we have which is 7". And we do have plenty of kids go for design type awards that push this limit.

Same here, except our published limit is 5.5". Our finish gate is actually a bit higher than that, but I'd rather have a safety margin. And the design-oriented cars that push the height limit are never competitive in the race.

X3.

I must say that some of the coolest design cars do push it awfully close too. Last years design champ was a beautiful red dragon that barely cleared the timer with all wings folded. It didn't set any speed records, but finished all 6 heats. But, man, when it came time to show during design phase this was one of the coolest cars and a very clever articulated wing which spanned at least 18 inches and the tail must have extended the length from 7 inches to well over a foot long. It was a sight to behold.

To think that this car would have never happened in a 3 inch height restricted rule is a souring thought.

Our District does one complete category of just 'Show'. Cars don't even have to make any size limits and they don't have to be in the 'Speed' races.
They do ask to keep it 'reasonable' for display purposes.