AMR Launch, Aero bits on GT Cars

I was quite lucky to be able to attend the AMR (Aston Martin Racing) Launch this Tuesday. It was great having a first look at their new car Vantage GTE for Le Mans and WEC. However the biggest surprise was meeting Bruno Senna as their new season driver there! This really was a last minute deal – I heard that AMR signed him just the day before launching. To be honest I was never a big follower of GT racing, but after having a close look at this beautiful GT car with some nice aero bits on it, I actually developed some interest! Here I want to share with you some pictures I took from the event.

Aston Martin Vantage GTE

Personally, I really like the look of this new car. The colour scheme is quite similar to Force India though  Very distinctive features from a competitional car to a road car are front air splitter, airdam, side skirt, rear wing, rear diffuser and some corresponding air inlets/outlets/conditioning pipes. For comparison, here is a picture of their normal Vantage V12:

From Aston Martin official site

V8 Vantage Roadster

A competition car is normally modified from a road car. Without those aero devices, it generates lift force instead of downforce due to the shape of the car. Here is a lift and drag coefficient figure provided by Racecar Engineering for Subaru Impreza:

Typical Cl and Cd values for Subaru Impreza

 It can be noted that there is significant downforce difference compared to drag difference with/without aerodynamics devices. At around 60mph, these aero parts become significant. Also from Racecar Engineering figures: at 70mph, the equivalent downforce is 51.8 kg (3.6% of car weight including driver), this value reaches 105.7 (7.4%) and 178.6 (12.5%) for 100mph and 130mph respectively as downforce is proportional to velocity squared.

 

Vantage GTE front air splitter

Look at the horizontal extension at the bottom of the car. This would create a high pressure region as air accumulated above the plate, therefore increasing front downforce. The air splitter would induce some drag, although the downforce benefit is dominating.

Vantage GTE Side Skirt

The side skirt prevents the mixing of high pressure air from the side of the body with the low pressure one underneath the chassis. It therefore smooth the flow down to the rear of the car and facilitate rear downforce generation.

Vantage GTE side view from rear

Here you can notice an exhaust pipe at the side skirt of the car - instead of mounting it at the rear. They seem to do this for better cooling at cockpit as this was their problem last year. However, I doubt whether the exhaust air at that position has any aero dificiency for the car. In addition, at the right top corner, you can see a big air intake which feeds the air into the rear diffuser.

Vantage GTE rear diffuser

Here is the rear diffuser of Vantage GTE. It has the wire mesh structure to smooth the air out of the diffuser. As mentioned above, the exhaust now is at the side of the car, so that the hole you can see above is not the exhaust outlet. Instead, this is an air condition outlet for cooling purpose.

Vantage GTE rear wing

Very similar to F1 cars, rear wing is one of the most important downforce generation device. It looks massive from a close view of the car – the span of it is actually wider than the car width. The position of rear wing can significantly influence the downforce generated. Generally speaking, as the wing goes rearwards and higher, more downforce can be generated due to the explosion of the wing to cleaner air. However, most regulation would limit the height of the wing so that designers need to take careful consideration of its location.

It was overall an amazing event from AMR on Tuesday night. And with the signing of Bruno Senna, the launch has caused massive attention. I’d wish him best luck in Le Mans and WEC – he’s a very nice driver in my impression.

McLaren MP4-28 Launch Review

With car launches nearly every day this week, we finally feel the return of F1 races. People are saying ‘It’s exactly the same as last year!’ everytime a new car reveals, even though they all know that 2013 is not a year for revolution. In McLaren’s launch, Jenson said that ‘under the skin, it’s so different’ – well we don’t really know before the Jerez test, but through bare eyes, we can see several detail changes on the new seasons car.

First of all, if you haven’t watched their launch video, you should really do it now! They have a brilliant built-up to the revealing of MP4-28:

With little change in regulations, one thing most team would do is trying to steal some good ideas from other cars last season. In terms of this, McLaren has somehow adopted Ferrari’s pull rod suspension and Red Bull’s rear suspension merging with driveshaft and track rod.

Covered Step Nose

The most obvious change is the covering of step nose with modesty panel. Step nose appeared in F1 since the 2012 season, when FIA modified the height limitation for nose cone and monocoque due to safety reasons. The 2012 regulation has a 550mm limitation for nose cone and 625mm for monocoque. As it’s beneficial to get more air flow underneath the car to feed into the diffuser, most teams are pushing to upper limit for both nose cone and monocoque. And in order to make up for the margin between them, step nose came out as the solution. The step doesn’t look good and there could be slight aero deficiency as the surface is less streamline like. So in 2013, regulation allows using of a modesty panel to cover the nose. It’s basically a thin carbon fibre panel that doesn’t have any structure function (it simply breaks down during front impact). However, the penalty of using this panel would be additonal weight at the front of the car. It’s the team’s choice to decide whether to use it or not considering its aero and aesthetic benefit and weight penalty.

MP4-28 Nose cone with modesty panel

MP4-28 Original step nose without the cover

Front Pull-rod Suspension

This was what Ferrari used last year (this year as well). Pull-suspension is basically an upside-down version of push-rod suspension (well not exactly, but you may understand it this way..). With the chassis and nose cone lifted up for maximum aero benefit, for stability, it’s good to lower down centre of gravity with a pull-rod suspension as all those springs and dampers are mounted at the bottom side of the nose. Actually McLaren must have made a whole change in the front part design due to the change of suspension.

McLaren MP4-28 Front Pull-rod Suspension

Rear Suspension Integration with Driveshaft

This was a Red Bull idea implemented since the development of RB5!  It basically utilise one of the wishbone to cover up the rear driveshaft. The covering of this part would make it more aerodynamically desirable. It smooths out the air at the rear of the car, therefore good for the efficiency of rear diffuser. From the picture below, you can see a very thick wide structure of the wishbone, which houses the whole driveshaft.

McLaren MP4-28 Rear Suspension

What Makes RB8 Faster – Flexi Front Wing

I’ve mentioned in a previous post on McLaren Spa Updates that McLaren is possibly using Flexi front wing. The flexi part is not new to F1 cars – Red Bull used it back in 2010, other teams tried on this principle as well although not all of them achieved preferable results.

How it works?

Basically, at moderate speed, the front wing runs at a relatively high angle of attack, maximizing downforce generated. At high speeds (long straights), the outer part of the wing tilts pack, reducing AoA, therefore reducing both downforce and drag (Although Research on Honda 2007 shows that there is scarce decrease in drag, although downforce deduction is noticeable). The shedding of downforce promotes better aero balance of the car – as what Mercedes want to achieve with their FW DDRS system. Flexi front wing also helps guiding the air around the wheel inward underneath the car, subsequently enhancing diffuser performance.

While Adrian Newey highlighted the loss of downforce due to ban of EBD as their major problem this year, the Flexi front wing should be one of the compensation they found.

In this December’s Racecar Engineering there is an interesting article regarding the composites used for flexi front wing. Basically, teams are using FEA (Finite Element Analysis) to evaluate material deformation under loading - they’re seeking for an optimised aerodynamics design that could meet all the FIA crash test requirements.

Picture from RaceCar Engineering

Front wing flexing back as shown in the green curve

As illustrated in the picture above, flexi wing can have less bending deformation and more twisting/tilting at the rear of the wing.

What about RB8 Flexi Front Wing?

RB8′s new front package is actually quite unique - in additioin to the wing flexing, they seem to have a rubber nose that can deform/tilt under loading. This pitstop from Vettle in Abu Dhabi caused lots of discussion as the mechanicseem to flex the nose when removing it.

However Vettle’s front wing was slightly damaged at that point, which may exagerate the nose tilting observed. Another GIF from Webber during the race does show quite large oscillation of the front wing as it goes through kerbs.

 Webber’s front wing oscillating in Abu Dhabi

Generally speaking, RB8 now has a really flexible front package – the tip of nosecone can bend downwards, also the outer section of front wing tilts back at high-speed.

Besides the benefit of downforce reduction and airflow enhancement around/underneath the car, Red Bull’s rubber nosecone may also create a mass damper effect, whereby car bounce is deducted, enhancing chasis stability.

The mass damper effect is well demonstrated in the video below, as can be seen, with a mass damper extended out, bumping on the main structure is significantly reduced.

The mass damper idea is not new to F1 – used by Renault back in 2005, although it’s later banned by FIA in 2007 (More to read if you’re interested in mass damper effect: J-dampers in Formula One). However, Red Bull’s Flexi front wing is an innovative idea extending this principal. The improvement of chasis stability also supports more stable aerodynamic performance for RB8.

What Makes RB8 Faster – DDRS

In the last few races, Red Bull came back to the dominate position again nearly as the situation in previous 2 seasons. It’s not due to a development of one single miracle part, but rather the whole aerodynamics pakage – DDRS, Flexi front wing and nosecone, modifidied exhaust profile etc. I’ll look into the DDRS first in this post and hopefully continue this series in coming posts.

After Mercedes’ Front wing DDRS and Lotus’ passive DRD, Red bull’s introduced their DDRS, kind of inspired by both systems. As the name DDRS suggests, it’s activated by DRS, the same as the Mercedes system. However, it’s fully equiped in the rear wing assembly same as the Lotus system.

RB8 now has a small hole on each side of the endplates, which is covered by a oversized plate attached to the rear wing main plane when DRS is not activated. When DRS is in operation, the rear wing tilts and exposes the holes, allowing air to pass through and guided out underneath the beam wing to stall it.

Source: Sutton Images

Red Bull DDRS inlet – notice the hole exposed as the covering plate tilts

As mentioned, Red Bull’s DDRS is fully compact in the  rear wing assembly. The duct curve is slightly shown in some close shots on their endplates.

Red Bull DDRS – Duct curve on endplates?

There’s possibly two outlets under the beam wing – one in the middle and the other near trailing edge, although the exact part it stalls – either the centre of beam wing or wing tips - is still ambiguous. ScarbsF1 inclines to the wing tip stall idea as he sees small impact on stalling the middle section (Analysis: Red Bull DDRS). Major media however believe that it’s the centre part that stalls although there’s no clear picture showing the existence of these holes. techF1Les came up with three posible conficurations with the last one mostly proved by actual observation.

Red Bull DDRS possible outlets position

Red Bull DDRS outlets at beam wing edge

I personally agrees with the wing tip stall argument since I’ve not noticed any clear picture showing the central part outlets. Some arguments regarding the central part stall working in coherence with diffuser does look interesting, although more evidence is needed for that.

I was a bit surprised as Red Bull introduced this system near the end of the season, while it’s going to be banned next year. However, they’ve somehow showed it’s worth investigating by continuing strong performance recently. This system has definitely given Red Bull a better qualifying performance and top speed boost during the race.

SingaporeGP Tech Updates

After going through two low downforce cicuits Monza and Spa, F1 came to Singapore, a narrow street circuit requiring high downforce. Correspondingly, most teams brought new setup for this track, while some of them gives a speed boost, others don’t seem to benefit anything. Successful examples are Red bull’s new break ducts and Mercedes Coanda effect exhausts. However Ferrari, using Alonso’s word, had a development error again, while Lotus expierenced a lack of grip throughout the weekend.

Mercedes

They’ve finally joined the group of ‘Coanda’ Exhaust after it was introduced by McLaren early season and used by Ferrari, Sauber, etc. The new exhaust utilise sidepod bulges to improve airflow passing through the sides of the car to the floor. Coanda effect basically describe the tendency of fluid attaching to the nearby surface. The bulge would help bending the flow at exhaust area down to the diffuser, therefore seal and speed up the airflow to create a low pressure area underneath the car. This effect increases downforce at the rear and gives advantage at low speed corners – that’s why it’s preferred in Singapore.

Mercedes Coanda Exhaust

Mercedes Coanda Effect Exhaust Detail

Red Bull

The narrow street circuit indicates huge pressure on the brakes and cooling system. Red Bull came with new brake discs and ducts made of CER, a new material whose wear resistance feature is about 4 times better than the old CCR.

Source: F1 Official Site

Red Bull Singapore Front Brake Duct Detail

They’ve also modified their front wing with slots in the front of wheel area to reduce wake behind and seperate flaps to decrease drag induced by the high downforce setup.

Red Bull Singapore Front WIng

Williams

Williams was in quite good pace in Singapore actually with Maldonaldo hitting 2nd in qualifying, although hydraulic problem for Maldonaldo and KERS problem for Senna leave both drivers nothing in this race. They’ve introduced a much more rounded nosecone with centre bulge in this race, quite similar to the Lotus one.

Source: F1 Technical

Williams Singapore Nosecone

Ferrari

They brought two sets of wings into Singapore with the new one having more louvres on the endplates and deeper cuts on the top flap. There’s also 8 gills added to the side of the diffuser, wishing to generate more downforce. However, testing result on Friday was rather frustrating so that the team decided to use the oler version for Singapore race. This happened quite a few time throughout the season, which makes Alonso quite worried – Ferrari focused on understanding ‘development errors’

Source: F1 Official Site

Ferrari Singapore Rear Wing – Not Used

McLaren

They’ve modified their rear wing for Singapore and here is a nice flow viz picture of it.

McLaren Singapore Rear WIng Flow VIz