Post by scratchbuilder on Jan 12, 2016 12:15:51 GMT -5
Well, I have been suitably embarrassed and educated on the Autosport forum about the wooden chassis on BM. Apparently it WAS wood, but NOT GN. That explains the taper on BM and none on GN frames. I never knew that. It pays to ask, especially on the Nostalgia Forum of the Autosport site. Now to actually make the thing in brass.
Post by scratchbuilder on Jan 12, 2016 12:22:06 GMT -5
That was my thinking, aurora. As a patternmaker rapidly running out of work, I was acutely aware that the pre-War scene was easy pickings if only a suitable wheel were available. I mentioned that to Colin and he agreed to finance the new wheel for inclusion in his growing range of wheels and tyres, if I would design and organise it, which I immediately did.
I think the FF 030 shorty is a suitable motor. I happened to have a couple of Mashima tiny jobbies through my railway client. BM has two engines, so the model must have 2 motors, belt driven to a pulley on the rear axle. Generally though, I reckon an FF030 is ideal for these tiny, lightweight models. Maybe a scale model of Prescott in my shed would suit them?
Last Edit: Jan 12, 2016 12:22:56 GMT -5 by scratchbuilder
Post by scratchbuilder on Jan 12, 2016 12:59:51 GMT -5
I seem to be shuttling 'twixt here and Autosport nostalgia. I am now assured that Spider II had not a GN chassis, but a special 3" narrower HRG chassis and used that car's dropped front axle and 11" brakes.
Post by scratchbuilder on Jan 12, 2016 16:47:07 GMT -5
Considering I've had a few gentle chores and didn't start till after tea, I've got the frame done in brass with the springs made integrally from the 2 1/2x1 1/2mm brass strip. The fewer joints the better, where suspension is concerned. Sorry for the blurred picture, but my camera just will not take a decent picture in artificial light.
The rear springs on BM are very oddly arranged and they've also been cut into the bottom of the frame. This is all I can find out but still begs the question of how much vertical movement can there be with such an arrangement?
Post by scratchbuilder on Jan 12, 2016 16:55:30 GMT -5
Here is the new 19" wheel with a skinny tyre of a type that RS will be producing.
There will be 4 separate discs of spokes in pairs, front and rear which will give the appearance of texture and depth. The system has always been used in 1/43rd scale and it's about time we can enjoy its effects in 1/32nd scale.
Post by scratchbuilder on Jan 15, 2016 11:36:28 GMT -5
Here is progress so far:-
The frame is brass section, filed down to include the leaf springs and the bonnet frame is filed down 1/16th" rod.
The body panels are made not in litho plate, but K&S Metal Centre 16 thou. ally plate, which is quite the nicest aluminium I know. Malleable enough, but not doughy, like malleable sheet. It takes rivet detail well and punches well, which is how the raised area on the right hand body side was made, using 60 thou. styrene sheet. The shape cut out and then a suitably shaped piece was squeezed through in a vice.
The steering arm comes out of this piece. The seat is a rivet impressed, folded piece with the seat space cut out. John Bolster was a tiny man. He was smaller than his ladyfriend!
The motors are Mashima tiny ones. They came via N-Drive Productions, a model railway company for whom I have made many brass masters. These will be fitted with 3mm pulleys which I have on order from Nigel Lawton 009, who makes a series of clever drive systems for micro motors, using square rubber belts.
Bloody Mary had 2 JAP V-twins chained together, then the drive taken to a gearbox and finally to the rear axle. I shall be trying to replicate this as nearly as possible. To that end I have also ordered a 1.5mm ballrace from Nigel!
Here the pattern is shown, made from Ureol, for the bonnet, which despite its apparent simplicity needs to be bashed over a pattern to get the curves seen in plan view.
Finally, the instrument panel, which boasts one instrument and three switches and through which the steering column sprouts.
Post by scratchbuilder on Jan 16, 2016 11:56:03 GMT -5
OK, I had a clear up and then sat down at the bench and decided the grille HAD to be properly made as a shell. So out came the malleable ally and although thicker than the K&S plate it reacted so much better to the hammerform than the K&S. An hour and a half later and it had the strange Bloody Mary central rivetted bit and a piece to form the bottom which will be fixed when the exact height of the grille is known.
Upper left is the pearwood hammerform over which the ally was hammered and to which it was trimmed. The picture is actually twice sized. Cheers, Martin
Post by scratchbuilder on Jan 17, 2016 5:48:26 GMT -5
Gimme some warning, John. I'd need to have a clean-up first! In this weather, I tend to just dump stuff inside the door and lock up again. I have a small workshop inside, but the lathe is in the shed and despite the lovely sunshine it ain't warm enough to go in the shed.
Post by Peter Seager-Thomas on Jan 17, 2016 11:17:22 GMT -5
According to John Bolster….
In 1929 the first engine was a 1914 760cc JAP. When the rear cylinder flew off, another similar engine was used, swiftly replaced by a 981cc SV JAP engine.
In 1933 came an OHV JAP, again 981cc. An additional (identical) engine was fitted for 1934.
As built, BM had a GN front axle and a solid GN type rear axle, all with GN hubs. An Austin 7 axle was fitted in order to permit front wheel brakes, the rear GN hubs were replaced by Rudge ones (early Nash?) as once the power output went up the GN hubs kept splitting. I’m pretty sure the GN wheels/hubs were by dog drive, not splines.
Today the car retains the two OHV JAPs, A7 front axle and GN type rear with the Rudge hubs.
JB also built a second car with 4 JAP engines.
(From John Bolster’s ‘Specials’, words in italics are my own).
Post by scratchbuilder on Jan 17, 2016 13:20:17 GMT -5
Peter, Bloody Mary doesn't and, and never did have an Austin 7 front axle, only hubs, brakes and wheels. It has always had its GN rod type front axle, so that it could use its GN style 1/4 eliptics and axle attachments. I would agree that it probably had a Nash back end set up.
My problem is seeing in any detail, what's going on at the back just forward and just inboard of the rear wheels, but I'm having to just wing it from what I can decypher off the net.
Alas, fuel costs are such that I can't afford the luxury of going off across the land measuring cars just for my own interests.