Post by David Mitcham on Feb 9, 2016 14:31:18 GMT -5
Having seen Andi Rowland's post on his Pre-Wing Ferrari 312B build using the Politoys chassis I thought I should start a thread about my purely coincidental build of an earlier Pre-Wing Ferrari, the 1966 312, experimenting with the same running gear. Its early days but by trimming up the shell and removing extraneous bits from the motor/gear box pod (intended for the Lotus 72) I've found that the two fit very nicely together. The resin moulded gear box can be retained and there is scope for significantly reducing the size of the bulge (there to accommodate a conventional crown gear) behind the engine cover/heat shield.
I haven't started on the front axle end of the Politoys chassis yet (it will need a lot of trimming which could weaken it) and I may decide to make up my own using brass strip. The only other issue I can see is not being able to use my usual method for construction the suspension detail (soldered brass or nickel silver rod and tube) as the 'plastic' chassis is not going to take kindly to heat. I think glued aluminium rod and tube may be the solution - at least it will be light.
This build is probably going to be fairly slow as there are several other projects on the go (Alfa 308, Lotus 25 and the BRM P48/57 - once I receive the shells from my master, hopefully this week). Here are some photos of progress on the 312 so far. I'm still debating whether to build the Belgian GP winner or the short nose Monaco car.
Post by David Mitcham on Feb 10, 2016 13:17:42 GMT -5
I am a fan of the Pre-Wing cars and have built several to date - the BRM P83, Cooper T81 and Ferrari 801 have all been the subject of threads on this Forum. The Honda 301, Brabham BT19 and two Lotus 25s are in various states of being underway. So many cars and so little time!
Interesting project, David. I assume you are going to reshape the Ferrari's gearbox casting to take advantage of the smaller transmission gears? I suspect we will see a lot of scratchbuilders adopting the Policar transmission in the months ahead for their F1 projects, even if they are perfectly comfortable soldering up their own brass and music wire chassis. Packaging a Slot.it or even a Ranch Design crown gear is often a challenge that leads to other compromises, The bonus with the Policar setup is that there is a built-in motor to axle centreline offset which allows the body shell to sit properly low relative to the axle, but doesn't result in the motor poking up into the cockpit quite so much. For those of us who race our creations, the lower centre of gravity is an added benefit.
I'm looking forward to seeing what you come up with for the front end of the chassis.
Post by David Mitcham on Feb 11, 2016 15:20:31 GMT -5
Yes I'm carving away at the resin to reduce the size of the moulding above the transaxle/gearbox. There's plenty of spare material at that point and the gearbox molding at the rear is about the right size but I'll probably enhance it a bit and move the fuel 'bomb' which isn't in the right position. I did some work on the front end and cutting down the standard Lotus 72 part works and remains surprisingly rigid. I need to make up a front axle bearing through as the 72's wheelbase is somewhat longer than the Ferrari's. I hope to post some pictures tomorrow.
If this, and Mel/Andi's similar approach to the Ferrari 312B, works out maybe thought will need to be given to proxy series rules about chassis materials for 3litre formula cars and possibly 1.5 litres too - see Andi's Lotus 21?!
There are no restrictions as to chassis materials in the VRAA: brass, steel, plastic, whatever... So a complete Policar chassis, or hybrid 3D-print/Policar, or brass/Policar combo would be welcome. Once the current season is wrapped up, I plan to start an online discussion on where the VRAA might go for next year. I hope the members of this forum will take part.
Martin, VRAA is at the moment a proxy race for: For Grand Prix cars of the 1.5 litre Formula One era 1961-65 and GP2.5 – For Grand Prix cars of the 2.5 litre Formula One era 1954-60. (two separate contests to be held at each venue)
VRAA stands for Vintage Race Across America. It is organized by Stewart, (OLD23).
Post by David Mitcham on Feb 12, 2016 14:34:21 GMT -5
This afternoon's progress (doesn't seem a lot, it takes me a long time to think things out!!). As mentioned above i decided to use the Lotus 72 front end suitably cut down. To achieve the correct wheelbase I've made up a brass plate to hold the front axle tube so it sits behind the moulded axle carrier; this gives the correct wheelbase. There are a couple of holes in the top of the plastic axle carrier so I've screwed the plate into those. The brass plate also forms the front suspension upper rocker arms which need bending upwards slightly. Its probably going to be possible to do something similar to attach the bottom suspension links.
The body fits neatly over the resultant rolling chassis. Those of you with good eyesight may be able to tell that I've trimmed a lot of resin away from behind the engine cover. Although there is still plenty of room above the rear axle to reduce the height further the resin is getting a bit thin so I need to decide whether to leave well alone or take a more drastic approach. You may also notice I've shortened the nose as I'm going to build the Monaco car.
Apologies for the dull photographs - the light was going and I didn't want to use the flash.
Post by David Mitcham on Feb 14, 2016 15:20:40 GMT -5
A bit more action today. The front suspension/axle is complete - I've managed to solder uprights, the steering arms and lower wishbone parts in situ without melting any plastic. The motor (a BWA because it was all I had in the parts box) and other running gear has been installed and the rolling chassis has had a shakedown on the track. Despite the low power motor and no tyre truing it goes very well - the gear train is smooth and the handling is good. A run with the body loosely fitted also went well. So now onto the rear suspension and then the best bit - detailing the body!