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Tuesday, January 29, 2013

The Devil's in the (Lotus) Detail

Now that we've had the excitement of the live Lotus E21 Launch, the first F1 car launch of the year, we can let the excitement fade a little and turn to the experts in the F1 Tech to see what they're saying.

Before that it is worth noting that very little has changed in terms of the F1 Regulations and how we can see the E21 responding by way of design.

  1. There's a weight redistribution issue resulting from the increased weight of the Pirelli Tyres, adding about 2Kg to the overall package, so the minimum weight limit has been increased by 2Kg to compensate. This has resulted in the weight distribution requirement being revised to minimum figures of 292Kg-343Kg front to rear.
  2. The teams still have 7Kg of moveable ballast within the car.
  3. The vanity cover to hide the stepped nose has been allowed, but as James Allison said at the launch, Lotus have left it off because it weighs a few grams and, as of yet, they don't think that it will provide much in the way of benefit.
  4. Front wings have a more stringent deflection test to ensure they don't flex.  The amount the wing can deflect is reduced from 20mm to 10mm.  The experts all agree that the E21 "launch" front wing is a dummy, so we won't know its detail until testing at the earliest.
  5. The crash tests are more severe than last years - however that's governed by the FIA tests and is strength rather than design.
  6. The "active double DRS" systems have been banned, however passive solutions are still legal.  Interestingly the live Launch car did not show the Lotus Passive system, while the press pack photographs do show it up beside the airflow box above the drivers head.  

My first thoughts on the Lotus and the season ahead are:

The front and rear wings are relatively generic designs and as such probably don't tell us very much about the Lotus approach to these areas.

The nose is still "bent" or stepped if you like and the "vanity cover" set out in the above Regulations is going to be a hot discussion topic pre-season, and perhaps even into the early races.  James Allison ruled out the Lotus using the panel at this stage saying 
"We have not done it yet because a cosmetic panel would weigh a few grammes and that’s anathema. However if we find one which looks nice but more crucially which gives us a few more points of downforce we’ll put it on the car as quick as you like".
The expert thoughts on this, set out below, would appear to agree that this might well be a case of Lotus not giving anything away to its competitors at this early stage. Lotus obviously think that they've improved the car overall with James Allison saying that while it is an iteration of the E20 "the devil is in the detail and it adds up to a significant amount of performance"; as to what constitutes a significant amount of performance your guess is as good as mine.
We might be able to gauge the improvements amongst the different cars in the first race of the season but with the free use of DRS banned in FP and Qualifying only in race pace will the performance be really calcuable.  Pirelli think their tyres will provide an extra half second a lap so this improvement will also have to be added to the calculations.  Fastest race laps by each of the drivers should provide a clearer picture of how much use the teams have made of the off-season.

My first question, of course, is how have Lotus visibly altered the car over last years model:

Gary Anderson at the BBC says:
There are bigger downforce-producing turning vanes - curved bodywork - on the bottom of the brake ducts and more at the front of the sidepods, which are reminiscent of those raced by Red Bull and Sauber at the end of last year.
F1Technical's view:
The new car continues to feature a front push rod suspension, along with a pull rod suspension at the rear end of the car. The car's sidepods are largely the same, albeit different at the front, where the sidepod panel is now connected with the monocoque by a small, horizontal winglet just ahead of the radiator air inlets.
The nose itself is quite narrow and on launch specification is missing the bulbous underbelly which was present last season to help create balance.The suspension looks similar, which makes sense as the Lotus was one of the best cars last year at using its tyres.
One thing apparent on the launch car is Sauber style flow conditioners or ‘pod wings’ later utilised by Red Bull. It is thought that these little winglets have a lot to do with the airflow around the rear of the car especially around the exhaust exit and diffuser.
Also apparent in the high res studio images (below) are the odd bumps on the nose that James Allison refuses to explain. Note the lump on the right front (the left of this pic) is much larger than that on the left front. Usually you would expect to find damper mounts in this area but they would almost always be symmetrical.
Missing from the launch teasers are any turning vanes under the nose which likely means the team have concentrated their efforts in this region and don't want to give too much away to the other teams too early...The team seem to have adopted a sharp undercut in the engine cover under the Airbox.  This is likely done to maximise the upswept air from the sloped nose and re-purpose the airflow down to the rear of the car

The second question relates to the design of the area around the exhaust, improvement to which we know has become one of the holy grails since 2009

We can see once more that the team are edging their bets in the render department showing two variants of the exhaust solution. The physical launch car featured a Red Bull esque Downwash Ramp with Exhaust trough and cross-under tunnel but in the lower rendering we can see a more simple ramp configuration also ran by Red Bull throughout 2012 but can be traced back to Sauber early on in the season
The rear end of the car is the most different, with Lotus copying Red Bull Racing's exhaust ramp. This means the sidepods now feature a downward slope at the end, trying to pull the exhaust gases downward to the floor and around each side of the diffuser to increase the diffuser's efficiency and downforce generation.
The exhaust location of the car is crucial and it appears that Lotus has followed the Sauber (and later Red Bull) lead. The exhaust gasses exit from a bulge at the rear of the sidepod and the Coanda effect (in theory) draws it down to the edge of the floor in the inner face of the rear tyre. If it works properly the flow then seals off the diffuser from a vortex generated by the rotating tyre. In effect this style of exhaust could be considered a ‘cold blow’ diffuser.
Last year, Red Bull and Sauber had bodywork right back beyond the rear wheels. The exhaust gases stuck to that as the team guided them down to the gap between the floor and wheels to increase downforce. Ferrari and McLaren, by contrast, aimed the gases across a gap.
Lotus have gone for the Red Bull/Sauber approach. It's not possible to tell from the pictures so far whether they have also followed Red Bull in guiding them through a hole in the floor into the central section of the diffuser.
They were late to the party on the Coanda exhausts, which channel exhaust gas down to the diffuser, so there is more to come for them in this area than their direct competitors.
First/Final impressions?

As launched, the new Lotus E21 looks very similar to last year's E20 but developments will start to emerge when it begins testing next month.
It's certainly different to the E20 design, but will likely change before the first race in Melbourne. Aesthetically however, the car is arguably less impressive, as the new livery features more red on the sidepods and the engine cover, somewhat spoiling the magical effect of the legendary black and gold livery
The renders of the car from the front show how closely the E21 represents the previous carnation

Well it is a direct descendant of the 2012 car, that is clear. This makes sense as the Lotus was one of the most competitive cars last year.

The expert conclusion would appear to be that it's quite like itself from the front, its got a Bull's bottom and a sideways glance might convince you to remain Sauber (sorry).