1/8 Porsche 956

[ScratchBuilt]

Thanks John - I think tonight's update will be to your liking: lots of large pieces of styrene cut into smaller pieces of styrene!

So, at the beginning of August the chassis frame was underway but very much in the early stages. It has taken pretty much the whole month to get the main cockpit section relatively complete. Although the cardboard mock-up gives me a basic pattern to work to, it's been surprising how much I've had to put into this thing in order to be happy that it will be strong and accurate.

To start with, I worked on filling in the lower section of the back panel, either side of the engine mounting:



The two large pieces of box-section in the lower corners will give me solid fixing points for the engine support A-frames later. I put the 1/8" diagonals across the openings before remembering that I wanted to allow for dummy openings for the fuel tank plumbing and some of the water pipework. The larger round hoop was made from a few layers of 0.4mm styrene wrapped around a length of tube as a former - I then cut out the diagonal tube to suit and fitted everything into the gap. A piece of 0.75mm sheet glued in from the other side ties it all together.

From the front, I continued adding more diagonals and braces. The piece of fibreglass laid into the floor defines the front edge of the main rear firewall / bulkhead, and you can see in the corners where I've started adding some box and sheet to 'control' the bulkhead position:



The rear firewall was made as two panels, leaving a 2mm gap between them - this will allow me to add the central cockpit 'spine' later:



You can see here that I've also started building up the rear of the tub. Although the top of the engine A-frames fix to the roll-over hoop, the roll-hoop also needs a secure fixing to the tub. Two lengths of large box-section are securely anchored into the bottom of the tub and give me the main vertical supports - they also give me a solid base for the firewall panels.

The upper section has been reinforced with more diagonals for the firewall frames, and a mix of fibreglass and styrene panelling:



The upper fixings for the A-frames are two lengths of 4mm ali tube which have been pinned and secured into the rear frame - you can see one at the far left of the above photo. It would have been nice to have them slightly further forward as it would have given me more options for how I incorporated them into the frame, but they are where they have to be! The round hoop at the left is where the gearshift will pass through the fuel tank area - there'll eventually be a similar hoop in the front of the panel, with a length of tube connecting them.

The firewall frames are a mix of 1/4" x 1/8" and 1/8" square box-section, with sheet reinforcement on the back, and pinned together in various places:



Here's a better view of one of the ali tubes. The upper section has been panelled with fibreglass sheet and styrene diagonals, and I've added the two outer sill sections along the sides of the cockpit:



Moving to the front of the tub, I started the footwell section by cutting two panels in fibreglass and styrene and using these as a baseplate, pinned to the substantial crossbeam which sits below the driver's legs:



The inner sides are made from yet more 1/4" x 1/8" box, and will eventually be pinned into the main tube, as well as the connections to the crossbeam below. The baseplate has been cut to give me the shape for the pick-ups of the lower wishbones, and will allow me to build down to meet the floor panel.

The outer sides were made in a similar style, with some shaping and filing around the front end to allow them to fit together with the inners at the correct angle. More box section has been used to lock the two sides together:



The fibreglass panel at the left of the photo is the starting point for the front bulkhead - this will eventually be reinforced with two styrene panels, and have cut-outs for the master cylinders, etc. I cut a slot into the inner cockpit sides to fix the position, and will soon cut away more of the baseplate in this area to get the final shape - I've left it oversize for now. The front bulkhead has to extend below the level of the baseplate eventually.

In this final photo you can see the comparison with the original cardboard version again. I've made a start on the dashboard hoop, and will continue working on this area this week. At some point I'll glue the footwell onto the cockpit section, but the upper has to stay removable to allow access for fitting pedals, wiring, steering rack, etc. I'll have to get in there to paint it, too!



It's coming along well, but there's still lots to be done - and that's before I start on the outer skins in fibreglass and styrene (plus rivet detailing...). I reckon I'll still be working on the dashboard and upper section for the next few weeks, certainly. I'll have to lay-up more flat fibreglass before I can start the panelling, so that's something I'll also try to do this month while the weather is relatively mild. I'm hoping that by the end of the year I'll have something that looks more like an ali tub than a tube frame, plus the core of a drivetrain that I can hang off the back of it - I think that'll be a pretty good start to the project!

Thanks for looking.

SB

[360spider]

Awesome styrene work my friend.

[ferrariman81]

It's amazing how much more refined your work has become since those first couple of Porche's you built.
It's amazing watching you hone your skills over time.

[ScratchBuilt]

Thanks, ferrariman81 - you're right: there's a lot on my first 917 and 917-10 that I would do differently now, but that's the benefit of another fifteen years modelling experience and a lot more books than I had back then! if I can find new or better ways of making the parts as each project develops, that's great - it keeps things fresh for me, and hopefully stops each thread becoming 'more of the same'. The little styrene nut and rivet details from Japan have been very useful too, though! Maybe when the 956 is finished I'll go back to the 917-10 and give it a restoration? The bodywork and livery could certainly be improved (full Brumos colours?), maybe a new steering wheel (as per the 935 build), and perhaps some new wheels and tyres...?

That's for another time; meanwhile, the 956 continues. Before I permanently fitted the two sections of the tub together, I spent some time rough-trimming the inner fibreglass cockpit panels:



You can also see in this photo where I've fitted mounting tubes for the main dashboard frame (by the red clips). Annoyingly these are right in the way of where I would have loved to put some extra reinforcement between the two sections of the tub, but I was happy that I could get around this little problem. The next photo shows a detail of the joint, once it was all glued together:



The lower cross-member (where the floor will start to slope upwards under the driver's legs) is securely pinned and glued to the front of the main tub. A pair of lengths of 1/8" box run back from this into the insides of the tube and are glued to the inner fibreglass panels, with extra styrene strip reinforcement. Citadel 'Greenstuff' has then been worked into the joint and around the dash frame supports to help key both sections together. For a final touch, the outer frames which make up the front of the tub also have some small extension pieces which run into the rear section, and these too are pinned after fitting. At this stage it all feels surprisingly solid, and that's before I've added the outer fibreglass skin...

Next, a small diversion to the rear of the tub - I wanted to create the angled section under the fuel-cell area, so used six lengths of 1/8" x 1/4" box with a bit of trimming and filing, then filled the gaps with 0.75mm sheet styrene:





Back at the front, I started building up (or actually, building down) the underside of the tub to meet the floor. The pick-ups for the lower wishbones are recessed into this area - I'm not finalising the holes until later when I make the wishbones, though.



The upper suspension pick-ups will sit on the top of the tub - here's the early stages:



The front leg pick-ups are pinned through into the tub, and are made from 3/8" x 1/4" box section. The long beam in the foreground is the main support for the front dampers - this is also pinned through to the tub, and in time will be detailed and extended down to the floor.

After a bit more work:



You can see how the damper beam is spaced up on two 2.5mm thick pads to get the correct height. The extra length of box-section with all the holes will close-off the damper beam to the underside of the tub outer top panel. The lower wishbone front pick-ups are now fitted in place (requiring two holes to be cut in the floor panel to fit over them), and you can also see where I've extended the very front of the tub.

Nearly there for tonight! Next, I've cut and glued the fibreglass plates across the top of the tub - more reinforcement! They stop just short of the damper beam, and I'll add some smaller plates across the tub to connect this to the front pick-ups.





That's it for tonight. I need to finalise the angle of the dashboard frame fairly soon, as I can then start working on the outer panelling for the front of the tub. The flat panel across the very front needs more detailing, holes for the master cylinders, etc, and there's a whole load of other things to do. I've started trimming the floor to shape, but I don't think this will actually be fitted for a while yet...maybe!

Have a good week,

SB

[360spider]

Every time I see your hand on one of these photos I'm reminded how huge that thing actually is!

[John18d]

I agree with 360spider -

I work mostly with 1/12 now and that looks small compared to 1/8 - lol

Really amazing work SB to see this build come together.

You are truly a master at these 1/8 builds from raw styrene.

Cheers
John

[ScratchBuilt]

Hello again,

Yes, on the subject of size the tub itself is quite misleading - the finished car will be about the same overall size as the 935-78, and yet the tub is (currently) much smaller than the tube-frames from the older racers. What's interesting is that the width across the inside of the 956 tub is within about 1/2" (full scale) of the width across a S3 Caterham 7 chassis...and the 7 is not a big car!

So, the next job was to extend the basic dashboard hoop structure with some fibreglass panelling:





The joints were reinforced on the inside - the front anti-roll bar will eventually locate onto the front of these extensions, so they need to have a bit of strength.

In the next photo you can see where I've added top plates to the tub either side of the mounts for the damper cross-beam:



These will be trimmed back a little when the outer tub skins are added.

The damper cross-beam has been reinforced with some doubler plates, and a slight extension on the top which mates up with the tub top skin. The dashboard hoop has been given an outer skin of styrene, and a length of angle across the top edge which will locate the top of the tub:



I've made the inner and outer skins for the angled sides of the front of the tube, but these need to be refined a little. The top panel has several access holes cut into it, although some of these will be covered when the windscreen surround and dashboard are fitted:



It seems like I've been working on the front of the tub for weeks, so for a change I wanted to sort out the rear corners, either side of the fuel tank area. The outer skins here will be angled in two directions, so the supporting frame had to allow for this. Here's the left-hand side:



The right-hand side is a little different as it has to allow for the gearchange to pass through:



I've boxed-in the interior here as I didn't want anything to fall into the inside of the chassis! The greenstuff looks a bit rough, but it's all been flattened to the right shape for when the panels are fixed. There will eventually be a couple of outrigger frames to support the various rads and coolers which will mount to the tub in this area, so I might add some more internal plating to give me something solid to drill and pin into.

...and that's it for tonight. I've made a start on the detailing for the master cylinder mountings, so you'll probably see that next time when I've got it a bit further. Reference photos of the pedals themselves are a bit scarce, so they might end up borrowing details from some of the older cars - I'm still hoping I'll find the right photo, though. I'll continue rough-cutting the external panels in fibreglass and styrene, but I need to plan how I'm going to interlock everything.

All the best,

SB

[Raikkobin]

Wow, completely masterful work in every aspect. Huge respect and I have been following your builds for a long time. You have a talent which should be shared with the greater public!!

A question I have is why styrene is your method of choice in structural parts like this? Is it the rapid pace of building that is the advantage? I have scratchbuilt stuff with styrene a fair amount, but when it comes down to strength and fidelity, especially with a riveted chassis, wouldn't working with metal have an advantage?

The reason why I ask is with so many suggestions of strength, is there a reason why you aren't considering working with metal sheet, soldering and machining?

[ferrariman81]

Keep us posted scratch. Miss those big, beautiful updates

[ScratchBuilt]

Sorry for the slow reply, Raikkobin - I've had a productive couple of weeks since my last update, but I should have said hello earlier! My continued choice of styrene for the main construction is a combination of several factors: availability, ease of working, 'knowing the material', and the fact that I do most of my modelling sat on the floor in my bedroom!

Although an aluminium or brass construction would be appropriate for the 956 tub, I'm not really equipped to cut, shape or join these materials easily. For me, that's crossing into the territory of 'model engineering' rather than 'model making'. I like the idea of building using relatively simple tools and readily-available material - not everyone wants to spend years building a single model, but there's not really anything I do that couldn't be done by anyone else.

I'm pleased with the strength and solidity of the styrene tub - and it should improve further once the outer skins are attached. Yes, it means that I'll have to make it look like aluminium later, but I think I'll be happy with that decision when I'm trying to glue on dozens of rivet-heads!

So, what's new tonight? First up, I've been making the pedals:



The fibreglass mounting brackets on the brake and clutch pedals will be attached to both the floor and the front bulkhead, whereas the throttle pedal simply attaches to the floor. I found some good reference photos on a 'Scale Motorsport' CD I bought a few years ago, plus my friend Rijk emailed a couple to me, so they're as accurate as I need them to be. I'll probably add some texture to the pedal pads when I paint them, and there'll be some more detailing on the brackets when they're fitted into the tub.

Following on from the pedals, I've made good progress with the three master cylinders and fluid reservoirs:



These are still in 'kit form' for now, but don't need much work to be finished. The main bodies of the cylinders are 1/8" tube, and the two larger reservoirs are 3/8" diameter. The caps are 2mm thick, with the ribbing added by gluing lots of short strips of 0.25mm styrene around the edge:



Again, there's a few details to be added - the connections for the pipework, fixing nuts, some greenstuff to fill in the gaps, etc - but the bulk of the work is done.

The next job was one pf those things that I thought might give me some trouble, but - so far - it has worked out okay: the steering rack. On the older cars like the 908 and 917 the steering rack is clamped to the chassis with two pairs of blocks, so the rack itself can be made as a mix of different-sized tubes. With the 956/962, the rack casing has the mountings cast into it - and as well as mounting the rack to the tub, it also locates the rear legs of the top wishbone. So, it's a little more 'structural' than I've made before!

So, I started by measuring the basic dimensions from my reference drawing, and making a simple cardboard pattern. I made a template for the Y-shape ends from thin sheet, then used this to make the proper ends in 0.75mm styrene, gluing them either side of a length of 3/16" tube:



The wishbone leg will fit into the double plates on the forward side, the rack bar will fit through the middle of the 'Y', and the rearward side of the lower plate will give the second attachment to the tub:



I filled the gaps around the Y-plates with greenstuff, then filed and shaped everything to give a smoother transition from the main tube to the outer ends. The pinion housing lines up with the slot in the dashboard where the steering column support will be, and I can adjust the height of the rack if necessary by shimming underneath. My first job tomorrow evening will be to make a dummy top wishbone and make sure everything will fit into place - I know I'll have to trim the openings in the outer skin panels slightly to clear the rack mounts, but I need to err on the side of strength!

I have a couple of weeks holiday coming up, so I'm planning some new jobs that I can really get stuck into - make the steering wheel, gearshift, maybe the fire extinguisher bottles, maybe the main roll-over cage structure too! I won't be doing any fibreglassing, but there's plenty of these detail jobs I can spend some time on.

All the best,

SB

[GirchyGirchy]

Nice work, as usual...and is that a Vostok I see on your wrist, ya commie?

[360spider]

Very cool solution to make the ridges on the reservoir caps. Great work as usual my friend.

[heyes57]

Re: 1/8 Porsche 956

Just loving this latest masterpiece SB. If I can presume to make a suggestion for your next museum piece; I've always admired the Group 5 era cars with their big box guards and "cow catcher" from ends, but favourite of all time was the BMW CSL Turbo Group 5....what a car especially in either the Gösser Beer or Jägermeister liverys....
Just a thought. Keep up the great work.

Cheers & Beers

[ferrariman81]

Keep em coming SB. You're an absolute wellspring of knowledge.

[ScratchBuilt]

Hello again,


It's been a productive couple of weeks since my last update – having some time off work is always good. As usual, I've been able to do plenty of jobs I wanted to do, some jobs I hadn't expected to do, and didn't do a few things I planned to! I've got about seventeen photos to go with this one, so I'll break it into two and post the second half tomorrow night.


So, what's first? With the steering rack drilled and pinned in place I made a couple of cardboard templates for the front upper and lower wishbones – I wanted to be sure that the suspension pickups were in basically the right place, and that the damper mounting wasn't about to get in the way:



Looks good so far. I've deliberately left the pick-ups undrilled for now until I start making the wishbones, so I've got a bit of wriggle-room for correcting the set-up geometry. The lower wishbones will be quite solid in construction, but the uppers are going to be a little 'fiddly' – I'll need to be careful how I make these.


Next, I made the centre spine which divides the cockpit. I've left slots in the rear bulkhead and the front crossmember, so there's no problem getting the alignment right, and hopefully it will stiffen the floor. I made it in three layers – 0.5 and 0.75mm styrene for the outer skins, and a fibreglass centre – which should help to avoid warping over time. You'll see in a later photo where the swaged holes have been cut out, and a slot added for the upper seat mounting; when it's finished it'll also have a lip added to the top edge.



I wanted to get the tubular roll-over hoops underway during my holiday too, as I knew these would be a time-consuming job. As well as making the actual hoops, I also had to start making the folded brackets which would attach them to the tub, and to make those I had to make sure the tub skin was layered-up properly.


Here's the rear hoop over the top of the fuel cell:



At this stage I had layered the inner fibreglass skins with the outer styrene skin, then made the top brackets to suit. The ali tubes at the rear corners will eventually connect to the main hoop, and provide a neat location for the brackets in the meantime. The hoop has been formed from two lengths of plastic-coated wire rod, with short sections of styrene tube threaded over the top – Greenstuff will fill the gaps, and there will be lots of filing and smoothing to get it all looking right!


The fuel cell top panels received more attention – there will be two large swaged holes in the top of the tub where the fuel filler and breather tubes will exit, and a third hole where other fittings attach to the bag tank. The black rings of till-roll tube will create the swaged edges, but I also cut through the fibreglass layer so that I could inset three styrene discs as the 'top' of the bag tank. If I'm lucky I can add the detailing to these discs but leave them 'floating' in the top of the tub – might make it easier to get everything lined-up when the bodywork is eventually fitted.






With the rear hoop under control, I spent some time working on the front hoop. For now I've dummied this up with length of (slightly oversize) flexible fire-extinguisher piping, but I need to make it properly as per the rear hoop. The mounting brackets for this hoop are more complicated, as they sit at the intersection of the dashboard and the main tub, and wrap over the sides:





I've made them oversize for now, but will fettle them to shape when I've got the hoop ready – they need to be aligned properly. Here's a better view of the four brackets made so far:



The last two brackets sit on the top corners of the dashboard frame, and are on the list of things to do this week.


I'll continue the update tomorrow night – steering wheel, gearshift and fire-bottle action!


SB