Scarbs blog

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http://scarbsf1.wordpress.com/2011/02/01...explained/


Renault have found a new solution to the blown diffuser concept. In fact they’ve turned it on its head. With an exhaust that exits at the front of the sidepods.

Last years teams reintroduced the blown diffuser concept, either by blowing exhaust gasses over the top of the diffuser, or by creating an opening into the diffuser to blow inside the diffuser. Both solutions created more downforce. With the latter solution now banned, it seemed the less effective over-blown solutions are all that’s left to race. However LRGP have found another way, blowing the front edge of the floor.



For a diffuser to create downforce it needs as much flow to pass through the venturi as possible. Teams arrange bargeboards and other aero devices to build up a high pressure region ahead of the floor to ensure the greatest mass flow underneath. Its then down to the expansion ratio of the diffuser to pull that flow through. Last years blown diffusers improved the expansion ratio, but not the flow ahead of the floor. What Renault have done in to lead the exhausts forward through the sidepods (about 1 meter) in-between the chassis and the radiators, then turn the exhaust 90-degrees to point it down towards the leading edge of the floor. The exhausts gasses follow the curved leading edge and round underneath the floor. This accelerates the flow under the floor for more mass flow and hence more downforce.


Problems with this solution are mainly to do with heat and engine mapping. With exhaust temperatures of 6-800c some clever insulation solutions are needed to keep hits heat from the fuel tank, radiators and a electronics. Then the Renault engine team lead by Rob White need to design exhaust tuning to deal with a far longer secondary pipe. typically longer pipes are better for low revs, somewhat contrary to the needs of an engine running at 18000rpm. Renault placed their KERS MGU and Battery underneath eh fuel tank, this was clearly to allow the packaging of the FEE. Unlike the McLaren F-duct, it is possible for this solution to be copied as no monocoque alterations are required.

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http://scarbsf1.wordpress.com/2011/02/03...-diffuser/



Ferrari F150 – Starter Motor Hole – Blown Diffuser
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Picture co F1Fanatic.co.uk
Ferrari are amongst many teams that have placed their exhausts down low close the cars centreline. In doing this they are passing some of the exhaust gas through the starter motor hole in the diffuser to create more downforce. This solution was likely given the cars exhaust and diffuser layout, but was proven when Felipe Massa’s fire on the third day of testing showed the flames passing not only over, but also through diffuser via the starter hole. Given the rule changes this year, this solution is surprisingly legal.Teams were using this legal opening in the diffuser last for year aiding their double diffusers. Using the opening as an extra slot to make the diffuser more aggressive, just as rear wings use more slots to allow them more angle-of-attack. Mid season in 2010 the FIA issued a clarification to reduce the size of the slot. This formally made it into the technical regulations for 2011 as article 3.12.7.

3.12.7 An aperture for the purpose of allowing access for the device referred to in Article 5.16 is permitted in this surface. However, no such aperture may have an area greater than 3500mm2 when projected onto the surface itself and no point on the aperture may be more than 100mm from any other point on the aperture.

It doesn’t state or prohibit what else the aperture can be used for, just its maximum surface area and width can be. A rectangular slot would be 10cm wide and 3.5 cm tall, a simple round hole would be a 66mm in diameter.

As the FIA moved to prevent double diffuser, the loophole allowing opening the floor was also closed to the kind of open fronted diffuser as used by Red bull and latterly many of the top teams. With this change in the rules teams are limited in how they can blow the exhaust into the diffuser. Aside from Red Bulls exploitation of the outer 5cm of floor, the only other option is to blow some of the gas through the starter motor hole.
By pointing the exhausts along the sides of the gearbox the fast moving gas flow will pass over the top of the diffuser, when it hits the trailing edge and gurney flap it will help draw more flow underneath the diffuser

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With a lot of expectation around McLarens new car, the newly unveiled MP4-26 did indeed surprise with its sidepods. Termed “U” shaped by Technical Director Paddy Lowe, as the two “L” shaped individual inlets together form a “U”. As with other design elements on the McLaren these are almost directly opposite to what the rest of the grid is doing.

What the team have done is to shift the inlet for the radiators at the front of the sidepod as far outboard as possible, to allow a freer flow of air to the rear beam wing (the lower element between the tail lamp and the top rear wing). Typically teams place the inlet for the radiators as close inboard a possible, as this airflow is the cleanest and with the most energy. This allows the sidepods to cool efficiently and hence have smaller inlets for less drag. By placing them outboard the vertical inlet catches the turbulent airflow from the front wheel wakes. Its this messy airflow teams try to keep away from the car with the pod fins. While McLaren may have to have a slightly larger inlet to cope with the poorer airflow, the benefit is that the better airflow closer the centre of the car can now be directed at the beam wing. With the double diffuser banned, a larger proportion of rear downforce will have to come the from the rear wing.

Also by creating this shape inlet it means McLaren cannot have the deep undercuts in the sidepods, which other teams use to direct the airflow around the sidepod and over the diffuser. McLaren have still managed to keep an undercut, but this is much smaller and lower, at about the same as the bottom of the raised nose.

Packaging radiators and ducting into this shape is far more complex than a simple inlet. The radiators themselves have a stepped upper edge, the protruding section reaching up inside the higher “L” shape section of sidepod. This makes the duct that directs air from the inlet to the radiator much simpler.

It remains to be seen if this set up works better than conventional undercut sidepods for creating rear downforce. Others team would be able to recreate the McLaren “L” shaped sidepod inlets. Although it would require a significant change the radiators and bodywork, making it a major package upgrade and not a quick test. For those teams that have not already tried this idea in the past, they will certainly being giving it some simulation time over the next few weeks.

[rolux08]

el ultimo de Colin es muy interesante

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Scarbsf1's BlogEverything technical in F1


McLaren MP4-26 exhaust – is the “U” bend a Front Exit?


MP4-26 - the "U" bend is visible between the diffuser and suspension
McLaren lead the way with innovations in 2010 with the F-duct, but they were late to debut their double diffuser and blown diffuser. In 2011 McLaren appear to be right on the tail of this year’s novelty the front exit exhaust.
So far in testing, the MP4-26 has been seen completing a diligent aero programme with the car appearing with two different format exhausts. One conventional set up which blows over the diffuser and another which appears to have a “U” bend in the system. This latter solution is believed to be a front exit exhaust as used by Renault (http://scarbsf1.wordpress.com/2011/02/01...explained/).

But as yet there is no sighting of the actual exhaust outlet.

Last year teams started to blow the exhaust over or through the diffuser to produce more downforce. With the method of opening the front of the diffuser up and letting the fast moving exhaust blow inside the diffuser, being the most effective route for more aero grip. Rule changes for 2011 prevented teams opening the front of the diffuser up (aside from a 5cm outer section of floor). So teams are faced with either blowing less efficiently over the floor or finding a new way. Renault have exploited another way, by leading the exhaust forward and pointing it under the front of the floor. Blowing the exhaust at the leading edge of the floor effectively creates more flow under the floor, which in turn creates more downforce. This front exit is a good aero solution, but packaging the duct from the main exhaust to the front of the sidepod is difficult due to the space constraints within the sidepod and heat rejected from the exhaust duct itself.


MP4-26 the conventional exhaust exits at the rear and blows over the diffuser
With McLaren’s conventional exhaust the four pipes merge into the collector and the secondary exhaust pipe points backwards to blow flow over the ramped outer section of diffuser. This set up has been used on and off consistently through the test. It also appears to the baseline configuration. As a lot of the aero tests using pressure rakes, flow-viz and long runs, are being completed with the conventional exhaust.


MP4-26 with the conventional exhaust exposed, the "U"bends crease in the floor can be seen
However other tests have been completed where the sidepod is revised. The sidepod features a bulge at the rear of the coke bottle, the bulged section appearing to house a revised exhaust system. Looking from the rear where the normal exhaust outlet can be seen is instead a “U” bend of exhaust tubing. With this set up the exhaust exit cannot be seen. Although several photos of sensors and cabling around the sidepod\splitter have prompted some fans and media to propose they are exhausts. In my opinion no photo as yet exposed the real exhaust outlet. With both systems, the rear of the floor and diffuser are the same.


MP4-26: This is how the "U" bend exhaust might look
Knowing the “U” bend system exists, I’ve tried to find proof for a front exit. One bit of evidence is on the launch car, which was initially unveiled without bodywork. Clearly a lot on the car was missing, but the floor appears definitive enough and just below the normal exhaust collector was a crease in the floor. This niche moulded into the floor is in the same location as the bulge in the sidepod when the “U” bend is run. Looking at its shape, I’d suggest this is where the collector and secondary pipe sit when the “U” bend exhaust is fitted. We can roughly predict that the collector sits further outboard and a little lower. The secondary pipe then curves inboard and then forward under the branch of four primary pipes (see illustration). Of course from here we don’t know where the exhaust routes, so we can’t confirm if it does blow back under the floor.


MP4-26: this is the aero rake used to measure flow accross the floor
Amongst the various aero rake tests McLaren have run, some tests features a huge array of pressure sensors in a rig mounted behind the diffuser. A later test had a simpler rig, which passes the floor ahead of the rear wheels. Initially this system ran with a conventional exhaust, and then later the rake was run with the “U” bend. I believe the rake was used to look at the pressure distribution under the floor. The two runs were used to map the different between the conventional exhaust and the improved flow of the front exit. So this suggests they are running some form of front exit.


MP4-26: the aero rake and "U" bend being run simultaneously
So where is the exit? I’ve looked at every picture I can find of the MP4-26 and I have yet to see any evidence of the front exit. I do believe its there, hidden behind the bargeboards somewhere below the sidepod inlet, or routed inside the splitter and blowing backwards. Other journalists at the Jerez test have confirmed some form of exhaust exit appears to be in there, kept out of sight both by other bodywork and the huddle of mechanics around the front of the car with the portable blowers to keep things cool when it returns to the pits. Also I’ve heard that the switch for one system to another takes 2 hours, which has reduced the McLarens track time.

But until we see a photo of the exit we can only speculate.

Ver graficos en el original

http://scarbsf1.wordpress.com/2011/02/17...ront-exit/

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http://scarbsf1.wordpress.com/2011/03/17...-analysis/



Analisis del nuevo Ferrari

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http://scarbsf1.wordpress.com/2011/03/23...mechanism/

Ferrari rear end – Exhaust and DRS Mechanism




A ScarbsF1 follower in the Melbourne pit lane sent me these exclusive pics. We can see the Ferrari stripped in the garage. There’s a huge amount of detail to take, but the key things are the exhaust routing for the EBD, the rear suspension and Rear Wing mechanism.



The exhaust loops forwards before turning back on itself to route towards the diffuser. This set up is used as it keep the exhaust well forwards within the sidepod, which helps to keep the sidepods tight and slim. We cant see the final section of floor, this might need to be removed in order to take the floor off.



Ferrari retained the pushrod rear suspension set up for the F150. To keep it competitive in aero packaging in comparison to the recently favoured pullrod, they have pushed the entire rocker and damper assembly to the front of the gearbox. In doing so they have placed the rockers nearly flat with their pivots pointing down. This keeps the assembly in the aerodynamic shadow of the engine and airbox, so effectively they don’t add any volume to the rear ends aerodynamics.



Lastly the “Drag Reduction System” mechanism can be seen sticking out of the gearbox. This is a hydraulic system and needs to be powerful in order to move the rear wing flap at quickly at speed. As both the flap will be heavily loaded by airflow and designers want the switch from closed to open to be in a matter of milliseconds.

i

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Del blog de Scarb

Everything technical in F1
The Flying Lap
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If you havent already started to watch this show, I suggest you really should. Theflyinglap.com, is a webcast and audio download going out every Wednesday at 6pm UK time. Peter Windsor runs this show from a studio in London. He’s had guests as varied as Frank Williams to John Surtees, Willem Toet and Sergio Rinland on the technical side. The show is an hour of live F1 chat with journalist and people within F1, often with aftershow chat continuing for upto an hour after the live show. the show is then available from smibs.tv, youtube and available as a free I-tunes download.

I dont know any other source for such a long and in depth insight into F1, that goes out every week. I’ve made three appearances talking about the new rules, testing and post race analysis. I’ve linked to the latest one below.

http://www.youtube.com/watch?v=WA4SHUbZZig

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http://scarbsf1.wordpress.com/2011/04/07...l-updates/


Pirelli will use the same two compounds in Australia as will be used in Malaysia. In Australia we struggled to tell which compound was being used. Pirelli mark each different tyre type with different colour logos. For Malaysia they will also add a radial stripe on the tyres sidewall to provide a more continuous flash of colour to be clearer for trackside fans and TV viewers. For this weekend the Silver marking will show the harder prime tyre and the yellow colouring for the softer option tyre.

Wet – orange
Intermediate – light blue
Supersoft – red
Soft – yellow
Medium – white
Hard – silver

Red Bull


KERS detailed – http://scarbsf1.wordpress.com/2011/04/07...-detailed/

Gearbox detailed – http://scarbsf1.wordpress.com/2011/04/07...-detailed/

Webber’s Australian pace and rear suspension fault have been clarified. It was suggested that the problem he had was a seized element in the rear suspension, possibly a heave damper or inerter. It now seems that while a rear damper was faulty, this occurred in the race and was not the total answer for his pace problems over the weekend.
Report here: http://www.autosport.com/news/report.php/id/90492

Rear Upright


Nothing particularly innovative here, but a nice view of the rear upright. Now made from aluminum as demanded by the regulations. The brake disc mounts to the splines on the titanium axle, while the brake caliper mounts to the two bolts beneath the upright.

Front upright


Already shrouded in the cooling ducts you can see how the main inlet feeds different ducts, one large one duct passes the around the upright to feed the holes in the disc, while smaller tubes snake around to cool the pistons in the calipers.

Renault


via Auto Motor und Sport
Renaults spare moncoque shows some of the detail not seen on the car, when its fully assembled. Firstly the Side Impact Tubes (SITs) are visible. At least two sets are, the lower SITs we saw at the Australian GP are not yet fitted. (Details here: http://scarbsf1.wordpress.com/2011/03/24...t-details/). Instead we can see an upper pair and single middle SIT. The shorter upper and middle SITs fit within the beaks above and below the sidepod inlet, in a manner similar to Ferraris sidepod set up.

The fuel tank area is quite large, since no refuelling is allowed The tank roughly sits behind the bare carbon fibre and the silvered section of monocoque. Note how it bulges outwards halfway down the side of the tub, this keeps the fuel low int he car, as much as possible. The radiator sits just above this bulge.

Whats not visible, surprisingly, is any amount of heat sheilding for the Front Exit Exhaust (FEE). From the Australian pictures we saw that the exhaust pipe runs beneath the radiator and wrapped within its own insulation. Not to downplay the issues in protecting the cars components from the heat of the exhaust pipe. There appears to be few changes needed to made directly to the moncoque to package this set up.

Also note the low position of the fuel filler, as this no longer needs to be easily accessible to the mechanic for in-race refuelling.

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Scarbsf1 Blog

Everything technical in F1 Todo técnica en la F1
FIA: Ban on Aggressive off-throttle Engine maps FIA:
Prohibición de agresivo mapas del motor fuera de aceleración

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Teams have been adopting exhaust blown diffusers (EBD) since last year and in 2011 every team has exploited the exhaust to some extent to help drive airflow through the diffuser. Los equipos han sido la adopción de escape difusores de soplado (EBD) desde el año pasado y en 2011 todos los equipos se ha aprovechado de los gases de escape, en cierta medida el flujo de aire para ayudar a conducir a través del difusor. As I have explained in previous posts on the subject (http://scarbsf1.wordpress.com/category/e...-diffuser/), the problem with EBDs is that they create downforce dependant on throttle position, so as the driver lifts off the throttle pedal going into a turn, the exhaust flow slows down and reduced the downforce effect, just at the point the driver needs it for cornering. Como he explicado en artículos anteriores sobre el tema (http://scarbsf1.wordpress.com/category/e...-diffuser/), el problema con eBDS es que crean carga aerodinámica depende de la posición del acelerador, de manera que los ascensores del conductor fuera el pedal del acelerador de tomar una curva, el flujo de escape se ralentiza y reduce el efecto de carga aerodinámica, justo en el momento que el conductor que necesita para tomar curvas.

If a team want to really exploit the benefits of an EBD then they need to resolve this off-throttle problem. Si un equipo quiere aprovechar realmente los beneficios de un EBD entonces que necesitan para resolver este problema fuera del acelerador. Last year Red Bull exploited a different mapping of the engine when off throttle (see http://scarbsf1.wordpress.com/2010/07/10...s-q3-pace/ ). El año pasado Red Bull se aprovechó de una asignación diferente de la del motor cuando está apagada acelerador (ver http://scarbsf1.wordpress.com/2010/07/10...-the-teams- Q3-ritmo /). By retarding the ignition when the driver lifts off, the fuel is no longer burnt inside a closed combustion chamber, but instead the fuel and air burn in the exhaust pipe, the expandign gasses blow out of the exhaust exit as though the engine is running . Al retardar el encendido cuando el conductor levanta, el combustible no es quemado dentro de una cámara de combustión cerrada, sino que la quema de combustible y aire en el tubo de escape, los gases expandign golpe de la salida de escape como si el motor está en marcha. This creates a more constant flow of exhaust gasses between on and off throttle. Esto crea un flujo más constante de los gases de escape entre encendido y apagado del acelerador. The problem here is that the mapping uses more fuel and creates excessive heat in the exhaust pipe and at the exhaust valve. El problema aquí es que la asignación de los usos más combustible y genera un calor excesivo en el tubo de escape y la válvula de escape. Renault reported that both Red Bull and Renault used 10% more fuel in Melbourne compared to last year, most likely due to these off-throttle mappings. Renault informó que tanto Red Bull y Renault utilizan combustible 10% más en Melbourne en comparación con el año pasado, muy probablemente debido a estas asignaciones fuera del acelerador.

With these off throttle mappings the fuel burns in the exhaust pipe, not the cylinder Con estas asignaciones del acelerador de la quema de combustible en el tubo de escape, el cilindro

As the engine suppliers have become increasingly comfortable with the heating effect of these off throttle mappings, teams have been able to use more of this effect in the race. Como los proveedores de motores se han vuelto cada vez más cómodos con el efecto de calentamiento de estas asignaciones o aceleración, los equipos han sido capaces de utilizar más de este efecto en la carrera. One of Red Bulls advantages this year according to McLaren is their use of aggressive engine maps for downforce. Una de las ventajas de los Red Bulls este año, según McLaren es el uso de mapas del motor de carga aerodinámica agresiva. At the Turkish GP several people pointed out the engine note on the overrun on Alonso's Ferrari during FP2. En el GP de Turquía personas varias señaló la nota del motor en el rebasamiento de Ferrari, Alonso durante la FP2. Teams have clearly started to drive the engine quite hard when off throttle, to keep the diffuser fed with a constant exhaust flow. Los equipos tienen claramente comenzó a conducir el motor bastante duro cuando fuera del acelerador, para mantener el difusor alimentados con un flujo constante de escape.

Now the FIA have stepped in to limit this effect. Ahora la FIA ha intervenido para limitar este efecto. Although initially scheduled to be in effect from this weekends Spanish GP the change will now take effect after Canada. Aunque inicialmente programado para estar en vigor a partir de este fin de semana GP español el cambio ahora se llevará a efecto después de Canadá. This clarification is based on Charlie Whitings changing opinion of how these mappings are used. Esta aclaración se basa en Charlie Whiting cambiar la opinión de cómo estas asignaciones se utilizan. At first some mapping was allowed, but these increasingly aggressive and fuel hungry mappings are changing the engines primary purpose. Al principio, algunos mapas se le permitió, pero estas asignaciones de hambre cada vez más agresivos y los combustibles están cambiando los motores objetivo primordial. Effectively when off throttle the engine is being used purely to drive the aerodynamics, this contradicts the regulation on movable aerodynamic devices. Efectivamente, cuando fuera del acelerador el motor se utiliza únicamente para conducir la aerodinámica, esto contradice el reglamento sobre dispositivos aerodinámicos móviles. Although this is a vague interpretation it can be justified. Aunque se trata de una interpretación vaga que pueda justificarse.

What is now required is that the engines throttles (at the inlet manifold) must be closed to 10% of their maximum opening when the driver lifts off the throttle pedal. Lo que ahora se requiere es que los motores de los aceleradores (en el colector de admisión) se debe cerrar el 10% de su máximo de apertura cuando el conductor levanta el pedal del acelerador. Unlike in most road cars, in an F1 car the engines throttles are not under the direct control of the driver via the pedal. A diferencia de la mayoría de los coches de carretera, en un coche de F1 los aceleradores motores no están bajo el control directo del conductor a través del pedal. The throttle pedal is instead the drivers method to request power\torque, the cars SECU then controls the level of throttle required to meet the drivers request. El pedal del acelerador es más bien el método de los conductores a petición de la energía \ par, los coches SECU entonces controla el nivel de aceleración necesaria para responder a la petición de controladores. So as the driver lifts off the throttle pedal, he is no longer requesting power\torque and therefore the throttles should close. Así como el conductor levanta el pedal del acelerador, que no es el poder más tiempo solicitando \ par y por lo tanto los aceleradores debe cerrar. what happens with these EBD mappings is that the throttles remain open, Fuel continues to flow then the delayed spark from the plugs sends the burning charge down the exhaust pipe. lo que ocurre con estas asignaciones EBD es que los aceleradores permanecerá abierto, de combustible sigue fluyendo a continuación, el retraso en la chispa de las bujías envía la carga quema el tubo de escape.

Now with the throttle closed to 10%, the amount of fuel that can be burnt will be limited and thus the blown effect will be reduced. Ahora, con el acelerador cerrado a 10%, la cantidad de combustible que puede quemar será limitada y por lo tanto el efecto de fundido se reducirá. so drivers see will a bigger variation in downforce as they modulate the throttle pedal, making the car less predictable to drive. para que los conductores verán una variación mayor en la carga aerodinámica, ya que modulan el pedal del acelerador, haciendo que el coche menos predecible para conducir.

Blowing the exhaust under the 5cm of outer floor (yellow) will be most penalised by the ban Soplado de escape en el marco del 5 cm de suelo exterior (amarillo) serán las más penalizadas por la prohibición

All teams will be affected to some extent, however the more aggressive that teams have been with the exhaust position relative to the floor, then the greater they will be affected. Todos los equipos se verán afectados en cierta medida, sin embargo, el más agresivo que los equipos han estado con los gases de escape posición en relación con el suelo, el mayor que se verán afectados. From the start of the season Red Bull, Ferrari and McLaren have blown the exhaust at the outer 5cm of diffuser. Desde el inicio de la temporada de Red Bull, Ferrari y McLaren han soplado los gases de escape en el exterior de 5 cm de difusor. this area is allowed to to be open and bow the exhaust gas under the diffuser for greater downforce. esta área se le permite ser abierto y la proa del gas de escape en el difusor de una mayor carga aerodinámica. these designs will be most greatly affected by the clarification. estos diseños serán los más afectados en gran medida por la aclaración. Renaults Front Exit exhaust is also likely to be a victim of the change. Renault salida frontal de escape también es probable que sea una víctima del cambio. Many teams have been developing Red Bull Style outer-5cm EBDs, such as: Williams, Lotus, Virgin, Sauber, While Mercedes are rumoured to be adopting a front exit exhaust. Muchos equipos han estado desarrollando Red Bull eBDS estilo exterior-5cm, tales como: Williams, Lotus, la Virgen, Sauber, mientras Mercedes se rumorea que la adopción de una salida de escape delantero. These may to need be shelved after Canada, in order to employ a less aggressive EBD. Estas pueden necesitar ser dejados de lado después de Canadá, con el fin de emplear a un EBD menos agresivo.