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28 Apr 2012
Wheels / Wheel Nuts & Pit Stops


Pit Stops have always been important in F1, less time spent in the box usually means less traffic on exit (if the strategy guys have done their job well) and could mean jumping an opponent in the stop. With Ferrari leading the pit stop game at less than 3 seconds for a stop this year it has become crucial to make faster and faster stops.

Ferrari & Mercedes have adopted a 'Nut in Wheel' solution which means the nut floats within the rim itself. This saves time for the tyre removers/fitters and gun man as there is physically one less job to do. However when things go wrong the system can be catastrophic. If the wheel isn't aligned correctly when fitted and the nut cross threads you can't simply remove the nut and place on the spare (Teams without the 'nut in wheel' solution have a spare to hand) This was the reason for Mercedes/Schumacher's retirement in China. If however the car hadn't left the box they would have needed to change all 4 wheels as you can't simply bolt on 1 wheel from another tyre allocation.
Ferrari have also gone down the route of less threads on the shaft, meaning less rotations of the nut. From the picture comparison below you can see that on the left Ferrari have 3 turns on the shaft with much wider spacings in comparison to McLaren (on the right) with 5 much narrower threads.


The Ferrari system is further helped by large retracting pins in the end of the shaft. These pins are spring loaded so when they push the wheel or gun on the pins push into the shaft. 

They work like so:

Step 1 - Place wheel over the shaft, as the wheel goes over the shaft the pins retract into the shaft, once the wheel is on the pins snap back.
Step 2 - With the pins in the out position the wheel is aligned to the thread and cross threading becomes impossible (Unless a retracting pin fails)
Step 3 - Wheel Gun man places the gun on which isn't impeded by the retracting pins as they only reach the outer edge of the wheel nut race.
Step 4 - Quicker stop due to less time on the gun with less threads to turn





McLaren have had problems at the left rear of the car firstly with Jenson in China and twice more with Lewis's car in Bahrain. Having the problem on the same side on 3 occasions I feel cannot simply be an error by the pit crew and must be some kind of flaw in the McLaren system. I have previously speculated about heat being an issue and still believe this could be plausible.  Especially if we consider that as the heated aluminum nut is taken off remnants of that nut could be left behind on the threads making placing a new nut on the threads difficult.  If we ignore heat and take Ferrari's system as the benchmark (as it's the fastest) we can see that McLaren also have the retracting pins in their shaft, however these pins are much smaller and offer no concrete method of holding the wheel in place whilst the nut is attached as the nut will also push over the pins allowing the wheel to unseat.

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27 Apr 2012
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Bahrain proved to be another exciting race spiced up by further technical upgrades bought to the race by the teams.
I have already posted an article on the main reason why Red Bull have made a leap forward here: http://somersf1.blogspot.co.uk/2012/04/red-bull-rb8-technical-analysis-why-red.html

Having reestablished themselves as a championship contender Red Bull's upgrades didn't stop at the ones shown in my other article, they have also employed another of Sauber's tricks for this year which is to place a slit in the rear of the floor just in front of the rear tyre. The reason for this slit is to reduce the impact of 'Tyre Squirt' this is the air that is pushed aside by the rotating wheel. In the case of the current regulations Tyre squirt effects the sealing of the diffuser as the airflow from the sidewall of the tyre pushes sideways converging with the diffuser flow and causes turbulence. The shape and position of the slot helps to move the flow of air, thus reducing the 'Tyre Squirt' issue. Ferrari also adopted this solution in Bahrain but with 3 slots as opposed to 1 and with a varied degree of angle. I expect by Mugello we will see most teams using the slot(s) with perhaps the exception of Lotus who seemed to have opened themselves upto the idea of using the tyre squirt to their advantage. As you can see in their picture the diffuser has exits on the outer proportions of the diffuser where most teams will usually enclose with end fences.





Monkey Seats


These are the little winglets that you see atop of the beam wing. With DDD and EBD the teams could generate more than enough downforce from the diffuser however with these options banned the teams have to more and more creative in how they gain downforce. Monkey Seats are not a new thing for F1 but simply a revisit due to the current regulations. Acting as a mini wing the Monkey seat acts in much the same way as the rear wing it sits within, providing additional rear downforce but comes with the same net drawback as the Rear Wing – DRAG. I'm expecting to see some flexing rear beam wing assemblies cropping up in order to bleed some of the downforce off at high speed. Teams like Lotus and Red Bull have integrated theirs into the beam wing with much smaller versions. The use of / positioning of the engine cover outlet will also be positioned in accordance with the particular Monkey Seat. Ferrari are having to sacrifice their low slung outlet in order to maximize the seat as you will see they have added a slit further up the engine cover.



Wheels / Wheel Nuts / Wheel Guns




I was going to do a separate article about this but feel it is pretty relevant considering the McLaren pit stop issues at Bahrain and China. Mercedes and Ferrari have this year both opted to run with a 'Nut in Wheel' solution which means the nut actually forms as part of the wheel. This is not to say it rotates as part of the wheel (would be a nightmare having to rotate the whole wheel whilst gunning it on) but floats in attachment to the wheel. Schumacher's race was bought to a climax in China due to this innovation as the problem of cross threading a wheel nut is compounded by the nut being attached to the wheel. Had the mechanic been able to stop Schumacher from leaving the box the team would more than likely have had to resort to replacing all 4 wheels again. This is due to the nature of cross threading a wheel nut as once the thread is stripped from the nut it must be replaced. In the case of the 'Nut in Wheel' solution the team would be forced to replace all 4 wheels as you can't have odd tyres (Tyre allocation rule).

I'm speculating somewhat here but McLaren have had left rear wheel issues in consecutive races firstly with Jenson at China and twice more for Lewis in Bahrain. Exhaust gas manipulation is still not an exact science and heat generation toward the rear left wheel could be to blame.
With both the China and Bahrain circuits being clockwise, heat generated by the exhaust that should be heading inbound over the diffuser could be drifting outbound toward the left side.  As the car corners and the 'Coanda effect' drifts away slightly on that side of the car. The hub that the wheel nut goes onto is made of Titanium however the nut itself is made of aluminium. Aluminium's thermal properties are much weaker than titanium however the nut could act as a heating sleeve expanding that region of the hub more quickly making it difficult to put the new wheel nut on.

Ferrari may be behind on the track but in the pitlane the team are excelling coupled with the 'nut in wheel' solution I believe Ferrari may have got a better handle than most on the ban of helium operated wheel guns. (Helium was being used by the teams to speed up their guns due to it being less dense) Their wheel nut apparently only has 3 rotations rather than the 6 most teams use which will also speed up the process.

McLaren & Sauber's sudden loss of pace


With F1 being the closest we have seen in a number of years most were surprised to see that 2 of the teams that were quick in the previous 3 races were out of sorts in Bahrain.
Just before the race there was a rainfall around the circuit which is very rare. This lead to a 10 degree slide in track temperature from Qualifying to the Race with temperatures in and around 40-42 and 30-32 degrees respectively. Thermal tyre degredation is something that all the teams are working hard on this year to manage and I'm guessing that due to the temperature variable this could have made an impact on the McLaren and Sauber as they tend to be much kinder on the tyres than those around them. A big drop in temperature means that from a mechanical grip point of view they were not able to work the tyres enough as their package would have worked better at a higher track temp.  Red Bull coming with their new package compounds the lack of pace shown by these 2 teams along with the first real showing of the Lotii's true race pace.

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  • Friday, April 27, 2012
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Red Bull having been the pack leader for the past few years had a surprisingly poor start to the 2012 campaign. I have alluded to the problems they were encountering in my previous articles but for Bahrain the team have opted to swallow their pride and adopt a package more akin to that on the McLaren and Sauber.



Their new package encourages the downwash effect from the top of the sidepod to stay attached with the exhaust helping to flow the air downward (Coanda Effect) whilst also keeping the flow from around the side of the sidepod attached for longer. Previously their airflow convergence was hampered by the use of a Tunnel feeding the sideways flow inbound through the false floor. (Picture below). Further to this Red Bull have added the same cooling / vortex generators on the top edge of the sidedpod that are found on the MP4-27. Along with reshaping the engine cover to push the airflow into the path of the downwash and sidepod flow generated by the use of the Coanda Effect.   All of this leads to more airflow over the rear floor which in turn generates more rear downforce.



Lastly here is a very basic picture of how the flow is is being directed around and over the sidepods (Yellow Markings), the circled area is the cooling slots that have been added and will also slow down the flow at the top end of the sidepod leading to the engine cover promoting better flow into the downwash area.



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We won't see many revolutionary changes to the cars until we get back to Europe and the Barcelona GP so I'll take just a small sideways glance at what a few of the teams are upto.

Red Bull




You can tell a team is at odd's when they split their drivers with different packages:
Vettel decided to use the original Pre Season test design (above) which features a much less aero sensitive exhaust configuration.   As I have previously talked about, the 'Coanda effect' is being used by the teams to promote exhaust gases to flow around the sidepods toward the rear floor to generate downforce.
With Vettel's configuration the exhaust is placed toward the rear of the car just below the suspension arm, using this as a deflection tool to push air downstream. This configuration (due to the exhaust layout) has a much longer sidepod region which means the airflow has to travel much further down the car before it interacts with the exhaust airflow. Having the exhaust in this position is much more neutral and will give a less 'twitchy' car however net rear downforce could suffer.



Webber decided to go with the updated RB8 configuration (Above) which sports a much shorter sidepod region which is derived from a much further forward exhaust position. The idea behind this config is two-fold and perhaps the reason why RBR are having more issues making the setup work than say the C31's layout.
Airflow from the sidepod is sent toward the tunnel created under the sidepods sloping exit creating another floor. The idea is that the two airflow streams interact with one another with the downstream airflow from the sidepod enticing the air from the side of the sidepod through the tunnel whilst still staying attached above. This should create a deck effect allowing 2 types of flow instead of just the one in the case of the C31.

Ferrari
When I saw the quantity of new bits on the F2012 I thought we may see a kitchen sink attached somewhere. We all know that Ferrari aren't happy with the F2012 and we will more than likely see a F2012-B at Barcelona however that hasn't stopped them trying out a number of new items this weekend.

Front Wing


This McLaren-esque front wing endplate design features louvres which will remove the boundary layer from the inner side of the endplate speeding up flow. In turn an area of higher pressure mounts on the outside of the endplate which will help flex the wing downward.

Wing Mirror Airflow Conditioners



Next to the wing mirrors a couple of small flow conditioners have popped up.  These are placed here to help direct the upper tier of flow over the sidepod rather than having the detached flow from the Wing Mirror spiraling downward toward the sidepod entry.

Twin element Sidepod Flow Conditioner


As I haven't mentioned these previously I will now as Ferrari seem to be the only ones playing with this concept.

Rear Wing


Ferrari's rear wing endplates sport turning vanes on the outside that are not prominent in the designs of other cars. These were also on the Malaysia spec endplates but worth mentioning.



On the main planes there are now two notches on the top edge along with flow separators that run through the centre of these down to the bottom edge of the lower plane.
I'm pretty tired and at work at the moment but the only thing that springs to mind here is that they are there to make the rear wing imitate having 5 sections ( Central, two outbound and then the channel on the outside of these make the endplates behave as extension of the main planes)
The cutouts help curb vortices (drag) by pushing airflow across the width of the section (Rather than having pinch points)

McLaren



McLaren's updates are a little less aggressive and so more difficult to represent. A new top main plane on the front wing which is beveled downward instead of outward is visible. Both cars are running a monkey seat (Small Wing that sits in the middle of the rear wing above the crash structure) these add more rear end downforce.
The use of a rear end airflow rig during free practice indicates some changes have been made to the rear diffuser. I'd also venture the angle of the exhaust position will have been altered to in turn use the Coanda Effect in a different way for this circuit.



Lastly after all the speculation about the Mercedes 'Super DRS' this picture of the ducting that runs the length of the chassis has cropped up. (For more on how Super DRS works have a look at my original article: http://finalsector.co.uk/mercedes-super-drs-f-duct/

All pictures in this article are Copyright www.f1zoom.co.cc
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Mercedes WO3 Super DRS / P&S Ducts (DDRS)


The quick version (Scroll down for a more detailed version)
Mercedes are using the rear wing flap to hide 2 holes in the rear wing planes, these holes become 'active' when the DRS is in use.  Think of them as a switch either on or off (They are fluid switches).  The old McLaren 'F Duct' worked using the driver as the switch (covering the hole in the cockpit)
Lets move to the front of the car to better explain what's being gained from the system.  Whilst the DRS is off (flap closed) air enters through the nose hole at the front of the car and is directed down the wing pylons and out of the slot gaps on the underside of the wing.  This speeds up the airflow under the wing which in turn creates higher pressure above resulting in a net downforce gain, pushing the wing closer to ground.  Airflow is also accelerated downstream as a reward speeding up the rear diffusers effect.
When DRS is activated and the two holes are revealed in the rear wing the air that once went down the wing pylons is pulled past these outlets and drawn toward the rear of the car  (through the tubing).  This lifts the front wing out of it's extra downforce position thus creating less drag on the front wing and slows the effect downstream of the diffuser resulting in a higher top speed.

Detailed Version
Firstly lets start by showing you how a rear wing works, next time you're out in a car moving down the road, roll down the window, put your hand out the window horizontal to the ground (thumb first) and you will feel the air rush over and under your hand. This is how a wing feels when stalled. Now take your hand and turn it vertically (upwards), you will feel the air push against your hand, this demonstrates drag. Now modulate your hand between that horizontal and vertical position and you will feel the air pressure change around your hand. Your hand is now creating the same effect a wing does on an F1 car. Imagine your hand in say a 30 degree angle and now perhaps you can imagine the sort of downforce that is inflicted on the wing. Pop your hand out again at roughly a 30 degree angle, but this time open your fingers (even better if you can do the Vulcan live long and prosper sign like me) and this should give you an idea of the separation of the wings to create the 'DRS slot'.

Onto the Rear Wing I think firstly we must look at the channel down the outer edge of the wing planes. Mercedes, Ferrari, Red Bull, Sauber (only their top plane), Force India and Lotus all have these channels. They are used to create additional surface area in order to increase the wing length by using the endplate to imitate the wings it's attached to.
Mercedes have gone one stage further than the others, by adding a lip to the top edge of the endplate enclosing the corner and causing a pinch point loading the top surface of the endplate to it's frontal tip. This pinch point (area of high pressure) in my opinion creates cross directional downforce, helping with balance in corners flattening the tipped side of the car. (As the car turns in gravity shifts the weight of the car, lifting one side. So imagine a tightrope walker using a pole for balance this is what is happening on the rear wing. Air travels along the channel, pinched in the corner and sent spiralling forwards along the endplate causing more downforce across that section)

Moving onto the bit that everyone is talking about, the slot that is only visible when DRS is activated
As with everything Aero related balancing drag/downforce is vitally important for cornering and straightline speed.  The Super DRS / F Duct has an advantage in both area's but only when using the system (so less so in the Race)

In this picture you can see that the flow whilst DRS is closed is marked in Black.  The nose hole is feeding the slots in the front wing via the wing pylons.  This accelerated airlow helps to 'suck' the front wing down and creates downforce, the knock on effect is accelerated airflow inbound towards the floor and onward to the diffuser.  When DRS is activated (Red Arrows) the air from the nose hole is forced past the wing pylons and through the bulkhead meeting with the airflow from the airbox at the crash structure.  Here the air is pushed around the beam wing, up the endplates and out the P&S blow holes forcing more air across the bottom of the leading edge of the top wing plane.
The linking of these 2 systems allows for more downforce whilst cornering gained from the Front Wing which then accelerates the Diffuser.  When the DRS is activated this downforce is bled from the Front Wing, Diffuser and Rear Wing.  Now if only the Mercedes was using the exhausts to promote the Coanda effect like Red Bull and McLaren.....

The pictures below show the holes in the underside of the front wing and the tubing leading from the sidepods and merging with the airbox exhaust



When Michael went off the circuit in Melbourne he went to great lengths to stop photos being taken of the underside of the W03
http://youtu.be/c5gjPrb43LA
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