15 replies to this topic

[Doug Nye]

OK technocrats - what do you reckon this engine might be?



Or this cockpit?



Or this air-start system?



...and transmission system?



...and another engine view?


DCN

Edited by Doug Nye, 18 August 2011 - 10:11.

[Vitesse2]

Would it be this, by any chance?

[f1steveuk]

Looks like a Matabele or two, 1000HP Sunbeam per chance??

[f1steveuk]

Would it be this, by any chance?

The 350 HP is always qouted as having a Manitou engine, whereas it was actually a one off special, so I think it's one engine from the 350HP and the others are the 1000HP 'Slug' though I thought that was chain drive, so I might be talking rubbish!

[mysteriousdriver]

This looks as if it could be a Rolls Royce Merlin set up for power boat racing.

Yes? No? comments?

Thanks Doug Nye for many interesting brain exercisers!

Mysteriousdriver

[arttidesco]

Not sure these pics are all from the same 'entity' but the top pic is unlikely to be a Merlin since the Merlin has two cylinder blocks one for each bank of 6 cylinders where as the top pic definitely has 4 cylinder blocks of 3 cylinders two each side. The V12 Sunbeam Manitou appears to fit the bill for the top photo.

[f1steveuk]

The Merlin was indeed two monoblocs (e.g no seperate head as such).

I'm fairly convinced the top piture is the unique 350HP Sunbeam engine (lightly based on a Manitou, but definetly NOT a Manitou).


Still pretty certain the other's are Matebele engines and it's the 1000HP Sunbeam 'Slug' ("Mystery Racer"), even though I cant see chains, bu they would bebehind armed plates anyway.

[Doug Nye]

Sorry for this tardy response. I'm lost in admiration for Vitesse correctly identifying the V12 engine pic as showing the power unit from the 350hp Sunbeam, and for Steve's erudition regarding the 1000hp Sunbeam, or 'Slug', for the in situ shots are indeed of her.

After one of our National Motor Museum Advisory Council meetings on Wednesday I mooched down into the Museum itself and found the 'Slug' with major body panels removed, and all that gubbins laid bare. It was too good good an opportunity to waste so I pulled my camera out of the Landie, and took the shots I then posted here. Chief Engineer Doug Hill then took me into his workshop to show me the recently re-completed 350hp Sunbeam engine, which as Steve recounts has been described as a Sunbeam Manitou aero engine, but is in fact more of an off-the-parts-shelf hybrid engine, a kind of Manitou with knobs on. Doug tells me it appears to combine a Manitou crankcase with Sunbeam Arab-derived single-ohc heads, I think with three valves per cylinder. Where the Arab engine itself had been an 11.76 litre V8 produced from 1916-18 its aluminium cylinder head, blocks and piston technology was pretty advanced. It begat the 12-litre V12 Sunbeam Maori which sported twin-overhead camshafts per bank and 48 valves, which then begat the true 15.39-litre Manitou quad-cam, 48-valve aero V12 - the baker's dozen produced then ending up post-WW1 mainly in power boats.

This 350hp Sunbeam engine once finally cobbled together from available bits and practises became an 18,322cc two-cam V12, with 36-valves, giving at best a claimed 355bhp. It did itself a terrible mischief some years ago...



...in which the worst afflicted piston actually ended-up upside-down within the bore. But just admire that twisted yet unbroken con-rod. Not bad for WW1-originated metallurgy. Below is the NMM's replacement - note the articulated con-rod design, the left-hand rod bearing on that lug on the right-hand rod, instead of on a crankshaft journal.



One interesting feature of the pistons is that large central pip cast beneath the crown, which actually passed straight through that central orifice at the top of the con-rod's little end, to add extra support to the centre of the piston crown by riding against the gudgeon pin (wrist-pin for the Colonials) within the rod.

Photos Strictly Copyright: The GP Library

DCN

Edited by Doug Nye, 20 August 2011 - 22:16.

[Vitesse2]

It was a bit of a lucky guess Only minutes before I'd been looking at a picture (plate 40) in "Motoring Entente", which shows the exposed engine as the car is being worked on at Pendine!

[Doug Nye]

Here's the old lady - 'The Slug' driven by Henry Segrave pushed the World Land Speed Record above 200mph for the first time. Those body panels hadn't been off for several years.



This massive side trunking - one each side - ducts air into the hip-mounted radiators which are just behind the cockpit, Lotus 72-ish, ahead of the rear-mounted Matabele V12 engine.



All the fixtures and fittings, and the manner in which the fuel tank is slung in the tail, are reminiscent of the Sunbeam 'Cub' GP car. No mistaking the pedigree of these babies...right down to Sunbeam's own thin-head bolts, thin nuts, slim washers, fine threaded shanks...all saving weight, even in such a monster as this...



Here's the rear engine, shot from astern, showing its battery of four ignition magnetos. The gizmo on the tail of that left-bank camshaft - also shown in my initial shots at the start of this thread - is the air-start distributor. It has a central connector for an air hose from an external compressor. High pressure air would then be pumped into it and distributed around the engine to start it turning, and drawing in mixture, whereupon the mags would be switched on, the ignition would spark and (at some point) away the Matabele would go, spitting violet flame from those vertical stub exhausts...and deafening everyone in the vicinity. Once that engine was running it was time to attend to starting the one at the front, which would be turned over by coupling it to the running rear engine.



Now here's what was more or less de Hane Segrave's view while all this was going on, give or take a body panel or two. The power take-off shaft from the rear engine ran to the left of his seat, into that lateral transfer box within the casing that would have been beside his left knee. Drive was taken through this by spur gears to the left, then back through the gearbox seen in my introductory pic - post 1 - and then via a diff to the countershaft across the car just behind the driver's seat, Each end of this countershaft carried a primary drive sprocket powering chains which drove to secondary sprockets bolted concentric with the rear wheels and so driving them. The car could be driven on the rear engine alone, and was indeed demonstrated in this manner just pre-war at Brooklands - which I think was the last time she ever ran under her own power.



Here are Segrave's pedals - the record-breaking loud pedal just that tiny spoon to the right...how disappointing...
But take note of the clutch housing to the front engine, within the scuttle-space there, to the left of, and beyond, the driver's feet.




On the left here you can see that clutch housing, and the engagement lever just to its rear, totally beyond the reach of the seated driver. What the Sunbeam crrew would do, once the rear engine was running would be to detail an intrepid mechanic to lean in, over this vibrating piece of thuggery, and use that tall lever to engage this clutch, which would then couple the drive from the rear engine to the front-mounted Matabele, and so kick it over in its own start sequence. Once the front engine had struck up, its drive could then be directed back into the transmission system and so to the rear-wheel chains. Oh, by the way, note the thin cable extending forward along the side of that massive chassis rail. Cable brakes, no less...



And finally, here's the left-rear drive sprocket, just visible within its 'armoured' casing... Segrave was pretty well protected against suffering a similar fate to poor Parry Thomas.

All Photos Strictly Copyright: The GP Library (access courtesy the National Motor Museum, Beaulieu, Hants, England)

I just thought you'd all like to see 'The Slug' in all her glory. Like Olga from The Volga - no great beauty, but dashed effective.

DCN

Edited by Doug Nye, 24 August 2011 - 08:15.

[arttidesco]

Next time I have trouble inserting the electric key thingy into the slot of my landladies Passat I'll remember just how difficult it was to start the Slug, thanks for your insight Doug

[f1steveuk]

Having spent some time researching LSR engineering, I have to thank you Doug for my first glimpse under the skin of the 1000HP Sunbeam, my education is near complete!

[ianselva]

Sorry for this tardy response. I'm lost in admiration for Vitesse correctly identifying the V12 engine pic as showing the power unit from the 350hp Sunbeam, and for Steve's erudition regarding the 1000hp Sunbeam, or 'Slug', for the in situ shots are indeed of her.



DCN

I'm afraid I guessed quite easily due to the overspray on the exhausts. By the look of the car ,I can see why they are looking for volunteers. Whilst I hate the look of all the over-restored cars around and like to see signs that the car is not a brand new almost replica , I do think they could have taken a bit better care of the old beast.

Ian

[Doug Nye]

Huge collection - small staff - long-hidden surfaces...but point taken.

DCN

[Catalina Park]

Great photos, thanks for sharing them with us. It is always good to see under the skin to find out how they did things back then.

[simonlewisbooks]

Didn't the 350HP engine feature cylinder banks of slightly-different capacity ? I think Heal's splendid "SUNBEAM RACING CARS 1910-1930" makes reference to this to highlight the parts-bin nature of the engine.