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1994 Penske PC23 Indy Car


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#151 Nigel Beresford

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Posted 13 November 2012 - 16:41

I have pictures I took of a Mayer March 84C with a bolt in rear bulkhead, so it had been around for some while.

Though it adds weight and complication and isn't structurally ideal, the bolt-on rear bulkhead was essential given the stiffness of the fuel cell, which you couldn't scrunch up and squeeze through a hole like a Formula One spec FT5 type cell. The cell was also required by the rules to be enclosed in a "ballistic" bag, which added further to the installation hassles. The fabricated aluminium oil tank was also housed within this area (mounted directly to the rear bulkhead), and access to the fixings for the roll over hoop (for repainting, as discussed at length above) was also made easier by having the removable bulkhead.

Edited by Nigel Beresford, 13 November 2012 - 16:58.


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#152 Patrick Morgan

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Posted 13 November 2012 - 16:45

I'm not sure when this method of construction started but certainly with the wrap up carbon / kevlar monocoques used by Lotus in the early 1980's had bolted bulkheads all along the chassis. The same is true of the 1986, 87 and 88 Lotus although they all had moulded monocoques. You can see the chassis are covered in aluminium bobbins and they are a devil to put together as they are all shimmed and the joint faces are angled where the chassis tapers.

With the Penske's at a wild guess I would imagine PC-15 was probably when this architecture started. The unique problem with Indycars is that the fuel cells are really thick rubber as opposed to the very thin cells used in petrol powered cars. With an F1 car for example you only need a relatively small hole to get the cell into the chassis as you can collapse the cell and fold it into a small bundle, insert it then pop it back into shape hence they have not had detectable bulkheads for some time. With an Indycar you can only really collapse the cell a little. See part 3 of our PC-23 restoration film for the removal of a cell - it's not a pleasant job!

I seem to recall Tony has a photo of the cell insertion into a PC-9 which clearloy shows that car did not have a removable bulkhead - it also shows some long poles...

Edited by Patrick Morgan, 13 November 2012 - 16:52.


#153 Patrick Morgan

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Posted 13 November 2012 - 16:57

To illustrate the point above here is a photo of a Leyton House CG901 chassis. The ring of bolts you can see holds down the cover that you remove to put the cell through. The cell fills the whole chassis cavity up to the roll hoop so it's a big cell. The gear linkage runs through a tube moulded into in the cell through which a carbon sleeve is fed. This is a real pain to get to line up when spreading the tank after it's been inserted. This cell also has a bonded in carbon collector so getting the folded cell into a small enough shape is quite a challenge.

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Leyton House May 2008 by dtperformanceltd, on Flickr

#154 Regazzoni

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Posted 13 November 2012 - 17:35

Thank you guys, very very interesting stuff.

I knew that the openings visible in the rear panel and sometimes laterally or above (in some wing cars with narrow chassis) was to insert the fuel cell.

What I didn't know was that the Indycars have thicker cells, which obviously requires other ways to get in.

I also didn't realize that the rear bulkhead could be bolted on, I thought the transfer forces between chassis and engine were quite large in a fully stressed engine configuration - which obviously are - but given the relatively large area and depth of the chassis there, I am sure there is more than enough torsional (Bredt-like) and bending stiffness available at that section. I note the two big engine attachment bolts on the bottom panel with the stiffening plate to help the transition of the point loads in the honeycombed shell.

I remember well the first few Lotus carbon chassis with all the bobbins around which revealed all the inside bulkheads and stiffeners locations.

#155 Tony Matthews

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Posted 13 November 2012 - 18:03

I seem to recall Tony has a photo of the cell insertion into a PC-9 which clearloy shows that car did not have a removable bulkhead - it also shows some long poles...

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Gettingit out rather than in! It was a damaged chassis, Rick Mears having hit the wall somewhere, and the wreckage just happened to turn up while I was there.

The bag tanks really are stiff, completely different from F1 tanks, plus the woven Kevlar ant-intrusion bag stitched on like a tight pullover.


#156 Tony Matthews

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Posted 13 November 2012 - 18:12

I also didn't realize that the rear bulkhead could be bolted on, I thought the transfer forces between chassis and engine were quite large in a fully stressed engine configuration - which obviously are - but given the relatively large area and depth of the chassis there, I am sure there is more than enough torsional (Bredt-like) and bending stiffness available at that section.

The average length of the fuel cell portion of the tub isn't that great, and the seat bulkhead is substantial and bonded in. I would think that part of the tub is pretty stiff even without the rear bulkhead bolted on.

I remember well the first few Lotus carbon chassis with all the bobbins around which revealed all the inside bulkheads and stiffeners locations.

The 'origami' chassis were clever, but when you see inside and realize how all the bulkheads, or at least the front ones, have to be fiddled down inside in halves, then shimmed and bolted to the bobbins and the halves to each other ...

#157 Patrick Morgan

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Posted 13 November 2012 - 18:26

The 'origami' chassis were clever, but when you see inside and realize how all the bulkheads, or at least the front ones, have to be fiddled down inside in halves, then shimmed and bolted to the bobbins and the halves to each other ...


Indeed! The 98T bulkheads are one piece but they are very slow going to fit. Essentially they are pinned in place with cut down M4 bolts. The un-threaded shank of the bolt acts as the pin with the nut only preventing the pin from moving rather than providing much by way of clamping load. I really feel for the mechanics in the day although one would hope once the bulkheads are in they are in for good.

#158 Nigel Beresford

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Posted 13 November 2012 - 19:49

FYI the latest Dallara has a far more flexible FT5 style tank, so these problems went away.

#159 Tony Matthews

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Posted 13 November 2012 - 20:31

Indeed! The 98T bulkheads are one piece but they are very slow going to fit.

My photos show split bulkheads! I didn't write a date on these contact sheets so I would have to check my diaries - perhaps the chassis I saw was an early one. Another car that I photographed but didn't draw...


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#160 Patrick Morgan

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Posted 13 November 2012 - 20:42

I think you did a 95T cutaway if I remember correctly.... I may be wrong.

#161 Tony Matthews

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Posted 13 November 2012 - 22:19

I think you did a 95T cutaway if I remember correctly.... I may be wrong.

I did the 91 and 95T, but I also photographed the 98T and 99T in detail. And illustrated the107, but that was a later technology.

#162 Tony Matthews

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Posted 13 November 2012 - 22:30

As to the rest of the drawings their fate is unknown - they are or were owned by Mercedes. The paper drawings did exist up until 2005, of that I'm sure but they disappeared along with all the micro film copies. The word is that they were disposed of - whether that is the case I can't say for sure.

Only just seen your response, Patrick. If this is the case it is pure vandalism, the thought of it actually makes me feel angry. I can see that keeping the drawings might, just might, be inconvenient, but how much space does microfilm take up? Well, I have guarded a considerable number of dieline prints from the drawings for the 265A, B and E if that is of interest. I bet Mercedes have all their original drawings back to 1890-odd.

I suppose there is a chance that they fell into the hands of someone who appreciated and rescued them. One of the joys of them is the different styles, line weights and annotation, seeing the difference between Geoff Oliver and Ian's work for instance. Oh well...

#163 Regazzoni

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Posted 14 November 2012 - 13:23

The average length of the fuel cell portion of the tub isn't that great, and the seat bulkhead is substantial and bonded in. I would think that part of the tub is pretty stiff even without the rear bulkhead bolted on.

The cross section mainly governs - in general terms - rather than the longitudinal length: its shape, closed is much much more stiffer than open, in particular in torsion [the cockpit opening is usually the weak area for this reason]; the area enclosed by the cross section, in torsion; the depth, in bending.

The aft bulkhead itself usually doesn't take directly the loads the engine attach points is feeding. If so, as it can happen in prototypes with wider chassis, then the bulkhead plate must be adequately stiffened to take those out-of-plane loads.

The engine attachment points are usually located on the contour of the outer shell, as the picture posted clearly shows: in this case, two in the bottom plate to the crankcase and two pairs either side to the cylinder heads. The reason of course is that shells work better structurally when loads lie in their plane.

The bulkhead is obviously required to stiffen – or better, to stabilize – the cross section contour and allow the spreading of the loads in the outer shell of the chassis, in particular into the two composite materials faces separated by the honeycomb core.

All this pathetic lecture, just to say that a picture of the bulkhead bolted on would be nice to see. :)

Any time, no rush. Thank you.



#164 Patrick Morgan

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Posted 14 November 2012 - 13:46

All this pathetic lecture, just to say that a picture of the bulkhead bolted on would be nice to see. :)

Any time, no rush. Thank you.

Again this is PC-26 but it's much the same as PC-23.

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PC-26 Bulkhead by dtperformanceltd, on Flickr

Sorry for the delay - I got distracted with work!

#165 Regazzoni

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Posted 14 November 2012 - 15:53

Posted Image

A quick one:

I can't see it clearly from this perspective, but it seems the bulkhead is not a sandwich construction, i.e. without a core (honeycomb, at least). Is it the case?

It would make sense - by and large - as the bulkhead is perpendicular to the main spanning direction of the chassis structure, it takes its loadings at the edges and it seems indeed that the plate is thickened also around the edges, likely in order to take care of the restraining stresses arising there.

#166 Nigel Beresford

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Posted 14 November 2012 - 16:16

No, I think it had core in it. It wasn't wafer thin.

#167 Patrick Morgan

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Posted 14 November 2012 - 16:37

No, I think it had core in it. It wasn't wafer thin.


It does have core in it. This bulkhead is from PC-23 08.

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PC-23 Bulkhead by dtperformanceltd, on Flickr

And for interest with the oil tank.

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PC-23 Oil Tank by dtperformanceltd, on Flickr

#168 Regazzoni

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Posted 14 November 2012 - 16:48

I didn't mean it was thin, I could see it was pretty substantial.

This beautiful picture explains it: it's the fitting thickness around the edges that misled me. Thank you.

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#169 Nigel Beresford

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Posted 14 November 2012 - 17:06

The "ears" on the sides mounted aluminium plates which carried the heat exchanger and/or underwing supports, so the bulkhead was solid carbon in these areas.

A lot of stuff in the sidepods...

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Edited by Nigel Beresford, 14 November 2012 - 17:22.


#170 Regazzoni

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Posted 14 November 2012 - 17:16

Thanks Nigel, that's what I meant.

Regards, Lucio

#171 Tony Matthews

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Posted 14 November 2012 - 17:59

I've spent most of the day scanning PC23 photos, and I should have one that shows edge detail of the rear bulkhead...

By the way, I didn't mean that the fuel cell part of the tub was so strong that it didn't need a bulkhead, only that is pretty substantial.

#172 Tony Matthews

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Posted 14 November 2012 - 20:15

Posted Image
Detail of the rear bulkhead flange on the PC23 chassis. To my surprise, although I have a lot of photographs of various Penske chassis being built and finished, I don't seem to have one like Patrick's of the rear bulkhead!

Edited by Tony Matthews, 14 November 2012 - 20:16.


#173 Regazzoni

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Posted 14 November 2012 - 22:02

Thank you Tony, very clear detail; no bolts in the oil tank width.

I have been thinking about the destruction of the Ilmor drawings.
If an historian - or Patrick Morgan himself - one day wants to research and write a book about the company, the engines they made, it means there is no cultural legacy, no hard documentation left?? That is tantamount to barbarism.

#174 Tony Matthews

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Posted 14 November 2012 - 22:32

If it happened then I completely agree.

#175 Nigel Beresford

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Posted 14 November 2012 - 23:27

Actually such a book already exists - "Ilmor, The First Fifteen Years", although it's more a word-of-mouth photographic, personal (& personnel) history than a pure technical record.

Edited by Nigel Beresford, 15 November 2012 - 08:50.


#176 Tony Matthews

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Posted 15 November 2012 - 09:00

I'm very pleased to say that I have copy, and it is treasured!

#177 Magoo

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Posted 17 November 2012 - 12:02

I have pictures I took of a Mayer March 84C with a bolt in rear bulkhead, so it had been around for some while.


Somewhat off topic but worth stating: in looking over these photos, and having worked on those old Marches, one can easily see what a cut above the Penskes were: materials, build quality, fit and finish, etc.

Not knocking the Marches of the world... they were built to a price and to a deadline and allowed a lot of teams to be competitive. But you look at this stuff and say wow. There is a difference.

Also off topic but worth stating: This weekend RP is on the cusp of a well-deserved and overdue NASCAR title. I wish RP the best. Very impressive young driver too, maturing at a frightening rate.

Back to the topic.

#178 Tony Matthews

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Posted 17 November 2012 - 13:28

The first Indy March that I saw was the 83C, and I remember slightly embarrasing myself - a not-uncommon occurance - by exclaiming to Alan Mertens that the rear end castings "looked like something from the Imperial War Museum!" I had to appease him by hurridly saying that it all looked massively strong. His comment was that they had no control over how the chassis were going to be maintained and treated, so the had to factor this into the engineering. Penske chassis were always so much more 'thoroughbred' in design and build, but then it was known who would be running them.

#179 Nigel Beresford

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Posted 17 November 2012 - 13:42

I always liked saying we were in the jewellery business.



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#180 Ross Stonefeld

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Posted 17 November 2012 - 14:40

Well, the industry is an over priced monopoly :p



#181 Nigel Beresford

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Posted 17 November 2012 - 14:50

I was being slightly tongue in cheek when I used to say we were in the jewellery business, but elegant design costs nothing and presentation is important because you are creating a product and image to represent the sponsors.

We were (thankfully) less constrained by cost than our competitors, but I always had enormous respect for the "production car" designers who had far greater constraints in terms of materials, cost and manufacturing time. That was a much tougher job.

Edited by Nigel Beresford, 17 November 2012 - 14:53.


#182 Ross Stonefeld

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Posted 17 November 2012 - 15:11

I was being playful too, and not referring specifically to Penske but our environment as a whole. Though if you'd have said the diamond business I'd have been more accurate! You guys have always been the last word in fit and finish and I always assume if you're not doing something then there's a good reason it's not done.

When I was barely knee high and the first racing video games were coming out, one of the earliest was of the Indy 500. I was vaguely aware of racing at that stage and knew more about the game than the actual series, and in choosing between the March the Lola and the Penske; I went with the latter because it was the only one with an LCD dash and that impressed me. :love:

#183 Patrick Morgan

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Posted 03 December 2012 - 17:05

Front Rockers now crack-tested and restored. Much to my relief our new pins fit....

Posted Image
PC-23 Front Rockers by dtperformanceltd, on Flickr

#184 Tony Matthews

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Posted 03 December 2012 - 17:57

Very nice! What a shame that Tamiya didn't produce a 1:12 model of any of the Penskes.

#185 Henri Greuter

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Posted 08 December 2012 - 21:11

Very nice! What a shame that Tamiya didn't produce a 1:12 model of any of the Penskes.



An 1:24 by AMT is the best you can hope for I'm affraid. They did the PC6 but that was it....



Henri

#186 Patrick Morgan

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Posted 11 December 2012 - 08:40

An 1:24 by AMT is the best you can hope for I'm affraid. They did the PC6 but that was it....



Henri


AMT did a PC-17 model I'm sure. I had one as a kid - Rick Mears who was very much my childhood hero.

#187 Magoo

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Posted 28 February 2013 - 07:51

Here's another Penske cutaway by Tony Matthews, the PC9 Cosworth. This one is in the Essex Petroleum livery of David Thieme (remember him?) as driven in 1980 by Mario Andretti.


LINK: Tony Matthews Cutaway: Penske PC9 | Mac's Motor City Garage.com



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#188 just me again

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Posted 28 February 2013 - 08:56

A great story and magnificient drawing as ever. The story made me wonder how a posh 80tish winnabago would look as a cutaway ;-)

Bjørn

#189 Tony Matthews

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Posted 28 February 2013 - 10:09

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A bit like this Van Hool, I imagine. :)



#190 Greg Locock

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Posted 28 February 2013 - 10:18

That's my kind of RV. Needs 6wd of course.

#191 Tony Matthews

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Posted 28 February 2013 - 10:20

That's my kind of RV. Needs 6wd of course.

Of course. This is the vehicle that had its canopy shredded in the paddock at Brands Hatch by a Harrier pilot with a sense of (wicked) humour.

#192 just me again

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Posted 28 February 2013 - 18:56

Posted Image

A bit like this Van Hool, I imagine. :)


beautiful. Imagine Sitting on the sofa next to driver drinking beer while on tour.

Bjørn

#193 Magoo

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Posted 28 February 2013 - 21:28

What became of Thieme? I heard years ago he was living in Paris.

#194 Magoo

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Posted 28 February 2013 - 21:29

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A bit like this Van Hool, I imagine. :)


Where are the cutaway sacks of money?

#195 Tony Matthews

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Posted 28 February 2013 - 22:54

I searched high and low but there was no sign of them. However, he certainly was a spender. I didn't make a great deal from the three cutaways that I did for him, but being flown to Monaco to see the Van Hool unit, a night in a hotel for me and my wife, a good lunch and helicopter taxi to Nice airport made a nice change. Also, invitations to two large functions in London, when he hired the Albert Hall and put on quite a show. We need characters in F1, and life in general.

#196 Magoo

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Posted 02 March 2013 - 21:28

I searched high and low but there was no sign of them. However, he certainly was a spender. I didn't make a great deal from the three cutaways that I did for him, but being flown to Monaco to see the Van Hool unit, a night in a hotel for me and my wife, a good lunch and helicopter taxi to Nice airport made a nice change. Also, invitations to two large functions in London, when he hired the Albert Hall and put on quite a show. We need characters in F1, and life in general.


Yes, bless the high rollers. This thing could never be what it is without them.

#197 Magoo

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Posted 02 March 2013 - 21:28

For your convenience, here are all the Tony Matthews cutaway stories featured at Mac's Motor City Garage.com so far, as a collection:


Tony Matthews at Mac's Motor City Garage.com


And here are links to all the features individually:


Maserati 250F

Williams FW07

Honda Accord BTCC

Ilmor Chevrolet 265A Indy engine

Williams FW14

Auburn 851 Speedster

Buick Ilmor Indy V8 Never-Was

1994 Penske PC23


Chevy Ilmor 265B Indy engine

Penske 8760 Series damper

Lotus 95T Renault

Penske PC9 Cosworth Indy Car



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#198 Patrick Morgan

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Posted 02 April 2013 - 12:25

We've finally got all the paint off the tub of 08 - it's A LOT lighter.

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Roll over mount by dtperformanceltd, on Flickr

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Left side by dtperformanceltd, on Flickr

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Front 1/4 by dtperformanceltd, on Flickr

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Right side by dtperformanceltd, on Flickr

#199 CSquared

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Posted 02 April 2013 - 19:54

Posted Image
Detail of the rear bulkhead flange on the PC23 chassis. To my surprise, although I have a lot of photographs of various Penske chassis being built and finished, I don't seem to have one like Patrick's of the rear bulkhead!

What's the wall outlet plug for? It looks so out of place . . .

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#200 Greg Locock

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Posted 02 April 2013 - 21:46

What's the wall outlet plug for? It looks so out of place . . .

Heating pad