# The concertina theory at Turn one lap one discussed mathematically.

#### David O'Reilly

##### A bad quali means I can go forwards in the race.
The concertina theory at Turn one lap one discussed mathematically.

With thanks to XL

So at 300 kph with 2 cars at a constant and equal speed a gap of 8.33 metres is actually a gap of about one tenth of a second.

That same tenth of a second at 80kph is only 2.22 metres. While accelerating a constant time gap will increase in distance creating the illusion of more space. It's still one tenth of a second.

When the cars decelerate from 300 to 80 kph that 8.33 metre gap shrinks to only 2.22 metres and that's only if exactly one tenth gap is maintained.

Brake half a tenth later and you have 1 metre. Brake a full tenth later and you have contact.

With 12 rows of cars maintaining a 1 tenth gap you only have 100 metres in total gaps. As it drops to 80 kph you now have only 26 metres in total gaps and to achieve this all drivers have to maintain 1 tenth gap precisely.. At this point the problem becomes very clear. Lots of cars and space rapidly shrinking to only 25 % of the space we had at full speed.

Say the driver in front seeks to maintain a safe gap (in metres) and brakes to achieve this. If on arriving at 80 kph he achieves half the 8.33 metres (so maintains 4.16m) he has doubled his time gap to the car in front and totally consumed the gap to you.

If the driver in front brakes even 1 tenth before you so 8 metres before your marker you will have contact.

What happens when we all do it?

Add to that the fact that on lap 1 turn one with full fuel and cold brakes and tyres, to create some space many wise drivers will add a few metres (lets say half a tenth) to their normal braking marker

If conveniently each row adds the exact same half a tenth safety margin, by the time row 12 arrives at the braking zone we have a braking point that has moved towards you by 46 metres.

But drivers don't act or react the same, some will allow a bit more, some a bit less, some will see braking as a chance to overtake or a sign of weakness and want to dive into that 2.22 metre gap.

And that leaves us with the Race Director each race saying “take care at Turn 1”.

Yet it still surprises at least some of us week after week.

#### Ben Eastman

##### 250RPM
So true....there's a fine line between "racing" in T1 and being reckless. Personally I'd prefer to take it cautious, live to fight for the next turn, even if it means going backwards or letting people go.

But always there is a few people trying to get cray-cray with spectacular results.

R5 will be fun, last year in Canada I went from 26th to 10th in T4 thanks to the chaos..if only we hadn't had red flags! Cheers Patrick Holzmann! lol

#### Jernej Simončič

##### 100RPM
If I'm in mid pack at start, my strategy is to lift throttle 300m early before the braking point to wake up the people behind and then I go back to throttle for some tenths and then brake.

I always watch broadcast speechlesly when there are 5 cars spun and try to recover, and someone tries to pass them flatout and makes a post-crash crash, it's just incredible

#### David O'Reilly

##### A bad quali means I can go forwards in the race.
So true....there's a fine line between "racing" in T1 and being reckless. Personally I'd prefer to take it cautious, live to fight for the next turn, even if it means going backwards or letting people go.
Indeed, I would add that I dont think I've ever seen a bold move in T1 ever make someones race. Maybe under throttle with a good getaway. in one league I was involved in (Codies Xbox at RD) we had the guideline that if you got them on throttle fair enough, but once you are approaching the braking zone you basicly hold position. So in essence the racing happened on throttle not under brakes as the gaps shrank unpredictably to 1/4 size.
I'm not proposing it here of course (so step away from the dislike button) but its interesting to differentiate between a move on throttle and one under brakes. I guess to if you find your self with a LOT of clear air in front of you you can be less cautious than you need to be with a car 6m in front of you.

If I'm in mid pack at start, my strategy is to lift throttle 300m early before the braking point to wake up the people behind and then I go back to throttle for some tenths and then brake.
Good plan, Ill try that. But then from P15 back I think ill try some pit lane startts for a while.

#### Ben Eastman

##### 250RPM
Indeed, I would add that I dont think I've ever seen a bold move in T1 ever make someones race. Maybe under throttle with a good getaway. in one league I was involved in (Codies Xbox at RD) we had the guideline that if you got them on throttle fair enough, but once you are approaching the braking zone you basicly hold position. So in essence the racing happened on throttle not under brakes as the gaps shrank unpredictably to 1/4 size.
I'm not proposing it here of course (so step away from the dislike button) but its interesting to differentiate between a move on throttle and one under brakes. I guess to if you find your self with a LOT of clear air in front of you you can be less cautious than you need to be with a car 6m in front of you.

Good plan, Ill try that. But then from P15 back I think ill try some pit lane startts for a while.
Personally having started in from P11 back to 25th this year, I find starting at the back the safest. 8-12 seems to always be where the collision takes place, the guys in front are saavy enough and have enough on the line that they don't seem to make silly mistakes, and when your way back there you see the insanity happen in front of you and can pick a line through it ALA Days of Thunder, driving through the smoke, hoping the car doesn't pick you up on the way down the track!

#### Marcel van der Linden

##### 100RPM
Its all about having braines or not.

#### Ho3n3r

##### 5000RPM
Its all about having braines or not.
Let me be the first to point out the irony.

#### David Greco

##### 100RPM
I do one thing each start of the race, and it works out well most of the times, I pray!

#### Georg Winter

##### 500RPM
Whatever helps. I medidate on the toilet. So far so good

#### Victor Ivanov

##### 3000RPM
I might use some of your methods cause obviously mine didn't work well