Regulating T-Jet Downforce

[SouthShoreRacing]

Why isn't measuring them all feasible?

Why do you need to check someone's entire inventory of magnets? The only ones that matter are the ones in the car on race day.

[NicoRosberg.]

To get a base number for the scales.

Once you have your number, then only the magnets in the car matter

[Dyno Dom]

Bob, I measured a car with club scale, my scale is 2.2 higher with same car so I have a max # to be legal per my scale and can follow up with other cars.
Nico, everyone's mag inventory would only be based on what is offered for measurement and quite time consuming.
A parameter for the actual race cars seems to be the way to go, picking a # from among the span of mag strength.

[NicoRosberg.]

But the 'span' can only be determined by testing all the mag's Dom's guys have.

[SouthShoreRacing]

Sounds good in an online forum but in practice it would be near impossible since the approach they are looking to take is measuring the magnets in the car.

1. Many guys have a large inventory of magnets
2. People are constantly switching magnets and magnet combinations so you would need to measure every possible combination. Good luck with that
3. People are typically acquiring new magnets over time.

K.I.S.S.

Measure the cars over a period of time. Determine a max reading. If someone who shows up with a car that has a higher reading either make them change or if change the max reading.

[NicoRosberg.]

That doesn't really solve anything

[Dyno Dom]

We have no idea how many AW/JL and Dash Blue/White mags are actually in members possession. If we focus on cars entered to race, a judgement could be made by picking a limit #.
An adjustment could be made for an individual car with a high downforce # by raising tire height or the club # could be re-evaluated.

[NicoRosberg.]

Sounds like a plan.

[BIG E]

Why isn't measuring them all feasible?

Deane, you have no idea how crazy running in that group makes me. I enjoy hanging with the guys, and Dyno is one of the best people in the group, but sometimes I just wanna smash something, pack up my gear, and go home (and I have, minus the smashing). It was lots of FUN when Dom came up with the FRACAS concept and we raced on his beautiful 6 lane Maxx Traxx circuit. But many of these guys have stretched it out WAAAY too far. You would probably not enjoy the racing, it's very frustrating at times, whether I win, or finish down the field on a bad night. I am a paid shareholder in the club track, so I guess as a member I can vent once in a while. Haven't been back since the pandemic shut me down as far as racing goes, but I will be returning soon. --- Ernie

[NicoRosberg.]

I have found it very common that HO racing people are adept at tripping over their own feet!

[Dyno Dom]

Hi Ernie, many of the guys are returning from the pandemic, and they are Fast. Yes, some have stretched the rules during the lax period, let's call it experimenting, but we're attempting to straighten that out. I hope all is well and to see you soon.

[Maddman]

The basic problem is the lack of a good reliable accurate scale. Without one any effort to regulate downforce is fraught with problems. For example most DMMs are accurate within 1% of a national standard when measuring ohms, and volts. From what has been posted on this thread the commercially available downforce testers are nowhere near that accurate.

Find (or make) a good low cost widely available and accurate measuring stick and then you can have this discussion.

[RichD]

My home made downforce tester uses a heavy mild steel bar. I was hoping that that would be less fussy about alignment than something that used actual rails. Soon I discovered that the whole works has to be level, so now I check that with a bubble gauge. The car also needs to be perfectly parallel to the bar to get reliable results. There is a 1/8th inch hole drilled in the bar to take a car's guide pin. The pin must not touch the edge of the hole. If I am careful about those things I find that I can always get reproducible readings.
Once you develop a technique that gets reproducible readings you can measure a lot of cars to determine what a typical car should read and a car with bogus magnets would stick out like a sore thumb.

[NicoRosberg.]

I think Madd's comment is about getting multiple devices to give the same readings.

He mentions 1% as a goal, where are the two commercial devices out there actually at?

[smalltime]

The basic problem is the lack of a good reliable accurate scale. Without one any effort to regulate downforce is fraught with problems. For example most DMMs are accurate within 1% of a national standard when measuring ohms, and volts. From what has been posted on this thread the commercially available downforce testers are nowhere near that accurate.

Find (or make) a good low cost widely available and accurate measuring stick and then you can have this discussion.

I was wondering if we're making this too difficult.

My track uses reed switches to sense a passing car.

If you could regulate the distance a reed switch is from the underside of a chassis, and simply use a light hooked to the switch that comes on when the switch is made, then you have a very cheap, efficient way of checking downforce.

Light up the switch, too much downforce.

Any thoughts?