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Porsche’s 917 in the words of the drivers

Porsche’s 917 in the words of the drivers

Dear Nigel,

I’m a Porsche 917 fan (and very happy about the podcast with Richard Attwood and the Gulf article in the latest issue).

Which driver do you think has been the best interpreter of the 917? Seppi and Pedro had a huge rivalry but many others had the chance to race this beautiful car…

Thanks a lot!

Niccolò Mazzoni

Dear Niccolò,

I’m not quite sure what you mean by ‘the best interpreter’ of the Porsche 917 – the guy who drove it best, or the one who told the best tales about it…

So many great drivers appeared in 917s, and I suppose if I had to pick a single name as ‘the best 917 driver’, it would probably be Pedro Rodríguez – not that I would expect Vic Elford to agree with me! I suppose Pedro comes to my mind first because I saw him win – virtually single-handedly – the BOAC 1000kms in the torrential rains of Brands Hatch in April 1970, and it stands in my mind as one of the greatest exhibitions of wet-weather driving I have ever seen. The 917 was hardly the easiest car to drive in the rain, yet Rodríguez made everyone else look clumsy and flat-footed.

I’m not basing my opinion on one race alone, however. Times without number Pedro excelled in the 917 – another of his greatest drives, for example, coming at the Österreichring in June 1971, only a couple of weeks before his death. He won many races in the JW Automotive era of the 917, as did Jo Siffert – and as, of course, did their co-drivers, one of whom was Brian Redman, the man described by Mario Andretti as ‘the most underrated racing driver in history’.

Some years after the 917 era Redman was told by a senior member of the team that he had, in fact, been quicker than both Rodríguez and Siffert around the ‘old’ Spa, a circuit he loved and feared in equal part. Not long before Wyer died, in 1989, Brian was moved to ask him, “Why did you never tell me?”, to which the famously dry ultra-Englishman said, “My dear Redman, if you’d known that, imagine what I’d have had to pay you!”

The 917 is unquestionably one of the most iconic racing cars of all time, and those who raced it love to talk about it to this day. In 1970, now usually in ‘short tail’ spec, and with the factory cars operated by Wyer’s team, it had become a much more useable car, and one adored by its drivers, but in 1969, the year of its introduction, it was woefully under-developed, and most of those who drove it that first year remember only terror. For the time its power was staggering – and its stability almost non-existent. So nervous of it were Porsche’s factory drivers that in its first race, at the Nürburgring, it was driven by Frank Gardner and David Piper, both of whom had been offered an unlikely amount of money to take on the task.

Long ago I talked to Gardner about the experience, and while – in the PC world of today – some of his more colourful remarks must sadly be omitted, I can remember at the time literally aching with laughter. Frank was always at his laconic best when talking about really bad cars.

“I got a call from the competitions manager,” he said, “and the money they were offering was certainly good enough to cross a strip of water and get in the thing. I think the reason they bestowed this honour on me was that every 917 driver was in hospital at the time, recovering from various stages of disrepair… I remember that Piper did one lap in practice at the ‘Ring, and was all for going back to England, but I pleaded with him to stay because the money was right.

“This was one of the very first 917s, with an alloy chassis, which was gas-filled. There was a big gauge in the cockpit, which measured the gas pressure, and that was there to keep you informed of the chassis’s condition. If it zeroed, they said, that meant that the chassis was broken, and I should drive mit care back to the pits.

“Once I knew what the gauge was for, I also knew that if it zeroed I wasn’t going to drive it mit care anywhere – I was going to park the bastard there and then, pick up my Deutschmarks and get home to Mum…

“Then there was the engine. You had about 300 horsepower at 5000 revs – and then between 5000 and 6000 you picked up another 300! So it was a bit of delight, really – and did I mention that it was on narrow nine-inch rims all round? The computer had said that nine-inch rims would make the car very quick in a straight line, but the computer wasn’t strapped in the bloody seat up in the Eifel mountains, where you tend to get the odd corner…”

Nor was that the end of it. “You sat between these pannier tanks, which bulged when they put the fuel in, so that was comforting – it took 40-odd gallons because it was pretty hungry. Then you started the engine, and – even with ear plugs in place – it was noisy to the point of being disturbing. It was bloody hard to think – you were horrified by all the activity, your brain numbed by the vibration, the power and the wheelspin.

“In those days, they were still gas-welding chassis, and this thing flexed so much that the actual position of the gearchange used to alter. You’d reach out for where the lever had been last time you used it – and it wasn’t there! It had moved.

“Nothing about the car was consistent, that was the thing. When it became airborne – which happened a lot at the ‘Ring – sometimes it would sort of float through the air, and other times it would crash down. It never did the same thing twice. Just when you thought you had it worked out, it’d pull another trick.

“It was simply indescribable, the motor car – and the weather did its best to help, as well. Snow and rain all the way. You were just so crossed up in the thing that you didn’t know which way was straight ahead in the finish. But we got it through to the end, seventh or somewhere, and in addition to paying me money, they tried to take up a collection for an Iron Cross, which they reckoned I’d earned…”

There followed an invitation to drive the 917 at Le Mans in June, but Gardner declined. “Again, the money was great, but I’d had my lesson. Rolf Stommelen went like hell with the thing, but he had the whole of the Fatherland on his back, and he had to rise to the occasion. Like I always said. I never really wanted to be the quickest bloke in motor racing – I just wanted to be the oldest. And that car was certainly going to interfere with those plans…”

Redman, a Porsche factory driver at the time, had similar memories of the early 917. “Of course it evolved into a very good car, but at first it was terrifying. Very early on, I got a call from Porsche to come and test it, and I thought, ‘Hmm, they’ve got 10 drivers in the team – why do they want me?’ So I said I had some very important business, but I’d see if I could put it off, and I’d call them back in an hour. I rang Siffert: ‘Seppi, have you tested the 917 yet?’ ‘No, no, Brian,’ he said. ‘Not me. We let the others find out what breaks first!’

“I drove one in practice at Le Mans in ‘69, and it was the fastest I ever went there – 238mph – but it was all over the road: on Mulsanne you were constantly having to correct the steering, and you just hoped that when you arrived at the kink you were on the right side of the road – if you weren’t, you had to brake!

“The spaceframe of the original 917 was pressurised, gas-filled, so that if the gauge lost more than so much pressure, you knew you had a crack. When that happened, they’d go round all the joints with a cigarette lighter!

“By 1970 they’d sorted the car – particularly its aerodynamics – out, and then it was nice to drive, but at a place like Spa it was so quick. In practice Siffert, my team-mate, went out in the car, but didn’t come round. Rodríguez came in, and said Siffert had stopped on the Masta Straight with a flat tyre. Pedro then took a jack, a wheelbrace and a tyre out to Seppi, and they changed it at the side of the track.

“On the Masta Straight we were doing 215mph on the approach to the Kink – and this was a road circuit, remember, not some purpose-built autodrome. Anyway, Siffert continued – and the same thing happened again. In came the car, all four wheels were changed – and then they said, ‘Herr Redman, now it’s your turn…’

“Every time I went to Spa I’d lie in bed, perspiration pouring off me – because I thought I was going to die the next day. I loved the track, but you really didn’t want to have an accident there. So now Siffert’s had two tyres fail – and I’m in the car…

“First lap OK, and the second, third lap faster, fourth lap flat out. Down Masta no problem, through Stavelot OK… On the return leg there was a flat-out right-hander – and the car went sideways as the left rear tyre came off the rim! It went every which way, at 180mph, I suppose, but I’d read somewhere that if you let go of the wheel, the castor action would straighten everything out, so that was what I did – and it worked!

“I got back to the pits, got out of the car – and Siffert fell on the floor, laughing. ‘Brian,’ he said, ‘you are the colour of your (white) overalls!’ And the next day we won the race…”

If the 917 had a devotee from the outset, it was the abnormally brave Elford. “I first saw the car at the Geneva Motor Show in the spring of ‘69 – and I just fell in love with it. It looked beautiful, powerful, sexy – everything you could want in a car. It was still very experimental at that stage, of course.

“At Le Mans in ’69 Porsche wanted to enter just one 917, for Stommelen to drive, but in fact the only guy who really wanted to drive one was me. Porsche said, ‘No, no, Vic, you drive the 908’, but I kept on at them, and finally they said, ‘All right, you can have a 917 – but it’s only going to last for six hours, and then it’ll break!’ I got Richard Attwood to co-drive with me, and we decided right from the word go that we were not going to race – we were just going to drive very quietly, very steadily, and see how far we got. True enough, the car did eventually break – but only after 21 hours, when we were leading by 50 miles!”

Elford concedes, though, that he too felt anything but comfortable in the 917 that first year: “I don’t think anyone did, although after that, when the aerodynamics were sorted out, we all loved it. These days the Mulsanne Straight is disrupted by Mickey Mouse chicanes, but back then it was a straight line for really high-speed cars – except for the little right-hand kink, which you don’t even notice in a road car. In a 917, though, you did notice it, believe me!

“Until the 917 arrived, probably none of us had ever been over 200mph, but suddenly this monster was doing more than 230, and it was very, very unstable. In the original 917, as you approached the kink, you couldn’t just snap off the gas pedal – if you did, the rear of the car would come off the ground, and start steering the front. Not very nice. What you had to do was ease very gently off the throttle, then gently back on, and probably go through the kink at about 180mph.

“By the following year, though, Ferdinand Piech – in my opinion, probably the greatest automotive engineer of all time – had taken over the 917 project, and it was a different car. You’d get up to a bit over 240mph on Mulsanne, and, believe me, 20 seconds at that speed is a long, long way, with guardrails on both sides, and then a lot of trees…

“Every lap you’d arrive at the kink at that speed, and OK, it took a few laps before I was brave enough to do it, but finally I was able to take it flat – even at night. And when I first did it, I came out the other side, and my first thought was, ‘Christ, that was easy!’ Quite seriously, it was much easier to do it flat than to lift off. Wonderful, wonderful, car…”

Motor Sport Magazine – The original motor racing magazine

Source: Motor Sport Mag

Red Bull RB9: Ducted Nose Slots

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Following on from the under nose slot of two years ago and the letterbox slot of last year, this years Red bull continues to explore aero solutions around the nose box.  However with revised nose rules this year, it’s an idea from Sauber that found its way onto Newey’s drawing board.  Now letterbox opening faces backwards and is joined to the slot below the nose with a duct, to overcome aerodynamics issues presented by the nose box.

Last year I explained that Red Bulls letterbox opening was largely to overcome the issues of the stepped nose.  Sauber also had a ducted solution aimed at the same issues which also resolves some of the airflow problems under the nose.  This year’s Ferrari 2013 nose slot has also been explained here.

A short modesty fairing, removes the 2012 slot but keeps the lower slot (arrowed)

A short modesty fairing, removes the 2012 slot but keeps the lower slot (arrowed)

In an attempt to keep the nose box cross section as small as possible and according to Newey to save weight, Red Bull haven’t adopted a full modesty fairing, instead the stepped nose is smoothed with a small fairing.  This modesty fairing removes the letterbox opening use last year.  But the high pressure generated under the nose and increasing boundary layer remain an issue, as does keeping the airflow attached over the step.  So the car keeps last years under-nose slot, but rather than exiting into the monocoque to cool the electronics, the slot now feeds a duct that curves up in an “S” shape to exit rearwards in the scalloped top of the monocoque.

RBR_Noseslot_flow

The lower slot feeds the “S” duct, as witht he Ferrari F138 lower slot, this relieves the pressure and boundary layer building up below the nose.  The duct then exits rearwards over the chassis.  As with Saubers solution last year, this helps keep the flow attached behind the stepped nose.

The "S" duct sends flow from below to over the nose

The “S” duct sends flow from below to over the nose

Although I’ve drawn the ductwork separately, the “S” duct is actually bonded into the nose box and isn’t removable.  No doubt we will get some pictures of the reverse face of the nose box once the season begins, to see the ductworks full details.

The V-Shape to the chassis creates the rear facing slot (arrowed)

The V-Shape to the chassis creates the rear facing slot (arrowed)

Packaging the duct requires some repackaging around the front of the bulkhead.  The bulkhead features a rounded indentation at the bottom to help turn the air fed through the lower slot through 90-degrees and then the anti roll bar and brake fluid reservoirs are packaged into the top half of the bulkhead and flanked by carbon fibre mouldings that follow the shape of the duct.

Red Bull have always kept a slight V-shape to the cross section to the front of the monocoque, this keeps the blockage in between the wheels to a minimum and aids the lower wishbone geometry.  The resulting valley in the top of the chassis allows the flow out of the nose duct to exit.

What’s interesting about the new nose layout is that the 2012 RB8 lower slots purpose to cool the electronics and the upper slots purpose to cool the driver are no longer catered for.  This further underlines the slots purposes were for external airflow and not primarily for cooling or other internal purpose.  It’s likely that the nose will gain a conventional driver cooling hole in its tip for hot races.

RBR_Noseslot

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Ferrari F138 Nose Slot

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F`138_nosehole

In the latter part of testing at Jerez the Ferrari F138 appeared with a slot under the nose cone.  In adopting a nose slot, Ferrari have followed other teams’ recent developments in this area.  Contrary to much rumouring the slot is a relatively simple aerodynamic solution to improve the air flow under the raised section of chassis.

Nose box aero issues

F138_profile

The nose and the raised section of chassis it attaches to creates several issues for the aerodynamicists.  Firstly the nose box forms a blockage in between the front wheels and reduces the flow that can pass in the gap between the wheels.  Secondly the very high nosebulkhead designs that are almost universal this year create a high pressure region under the nosechassis that is effectively creating lift, thus working against the downforce.

Boundary layer (yellow) builds up as flow passes under the nose

Boundary layer (yellow) builds up as flow passes under the nose

Lastly the nose and chassis present some of the longest flattest sections of bodywork on the car (floor excepted) and thus a boundary layer builds up along these surfaces and can create issues with separating flow. A boundary layer is the airflow that is effectively stuck to the car; whereas the main flow is passing over the car.  As the bodywork surface continues more airflow sticks and the boundary gets thicker.  As the boundary later is not moving (relative to the car) it is providing no aerodynamic benefit and simply causes flow separation and aero issues downstream.  It appears the nose slot is a solution to resolve these issues, which one of these creates the greater problem for the cars performance, is debatable, but a small aero gain can be had by easing this issues.

Nose slots

The RB7's slotduct  is formed by the layers of bodywork under the chassis

The RB7′s slotduct is formed by the layers of bodywork under the chassis

As long as two seasons ago, Red Bull also exploited a slot under their nose, its design was more discrete and even when the letter box slot at the top of their nose last year was introduced, the under nose slot largely went unnoticed.  Thus the RB7 had a slot created at the intersection between the chassis and nose box.  Rather than a slot being formed in the nose box shape, the slot was formed by a layer of bodywork being added below the chassis.  The small duct formed by this panel lead back to the front axle line, where it entered a small recess moulded inside the monocoque.  This recess was about the size of large paperback book and sported exit vents into the footwell area of the monocoque.  I suspect this area housed the FIA timing transponder, but probably not much else, due to its small size.  The cooling effect was probably of some benefit, although other teams do not see the need for specifically cooling the transponder.

The under nose slot reduces boundary and pressure, by venting into the cockpit

The under nose slot reduces boundary and pressure, by venting into the cockpit

In fact the benefit of the slot was the effect on the cars external airflow.  As air passes under the nose, pressure and a boundary layer would start to build up.  The airflow would then be split by the slotduct airflow adjacent to the noses surface, air would enter the duct, skimming off the boundary layer in the, process.  As the duct is also divergent it would reduce the air pressure under the nose at its entry, by the high pressure region venting into the slot.  The off body airflow, that is the moving stream of air a few millimetres away from the bodywork and thus clear of the boundary layer, would pass over the slot and the reattach to the under surface of the raised chassis.  This flow is moving faster and is at a lower pressure than the flow closely attached to the nose cone.  Thus this flow will have more energy to work on aero devices downstream.  By splitting the boundary layer and off-body flows at the slot, the preceding nose cone can be shallower, thus reducing the blockage it creates between the front wheels.  This simple slot effectively negates the three negative aero effects presented by the nose box.

F138 Solution

F`138_nosehole

Ferrari solution is very similar to Red Bulls slot, but the slot is formed in the nose box itself.  Legally the slot might be far forward enough to be considered the driver cooling slot, if so it will be restricted in inlet size.  Or if the slot is behind the FIA defined A-A bulkhead line, then it will not be considered part of the nose box and has total freedom on inlet size.

The slot is mated to a corresponding opening in the monocoque, this appears to feed into the footwell area, I doubt that its purpose is to be ducted for aero effect elsewhere on the car (i.e. DRS) or cool anything that isn’t already inside the cockpit (i.e. KERS).  The air most likely cools the driver from the ambient heat and the heat created by the power steering rack and electronics boxes.

This is a simple and effective solution, as the front bulkhead on the monocoque needs the slot made into it; it’s not something that can be easily copied in 2013.

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