11 replies to this topic

[Ray Bell]

As my investigation of the P3 Alfa rear end continues, it occurs to me that I really am not sure of a couple of parameters I formerly thought were correct.
1. That the rear suspension/drive train of the Monza Alfa was the same as the P3.
2. That both had been modelled on the rear end of the Tipo A rear suspension/drive train.
To elaborate, I recall that Alf Barrett explained to me the details of damage done in a crash in his Monza at Lobethal in 1939. That was the first time I ever heard of the split drive train.
Now I have magazine articles thrust in front of me that assert that the Monza.."rear axle was normal type, the gears having "Gleason" type teeth, whatever they were!" The accompanying drawing clearly shows a bulge in the centre of the rear axle - a single axle-mounted differential.
This conflicting information is just too much for my meagre resources - so I call on the help of the experts.
If Barrett's car had a single drive shaft, however, what was he talking about when he spoke to me nearly twenty years ago?
And what of my other dilemma - that with the Tipo A rear end. Further comment comes like this: "From the gearbox of each engine issued a propellor shaft enclosed in a torque tube and having a single spherical type universal joint at the front ends. Two separate differential gear units in alloy casings were mounted side by side at the rear, and thus each engine was an entirely separate unit which only drove its own particular rear wheel, although both engines were positively geared together to prevent one running faster than the other."
In another part of the article he writes, however, that there were separate crank handles and that the engines had to be started separately!
One issue with this lot is the torque tubes. Thinking about this, how can a rear axle pivot - as one does with a torque tube arrangement - on two separate pivot points without inducing stresses that will kill it. Or was there a slip joint of some kind in the middle of the axle.
And how, if the engines were geared together, did the differential work?
Beats me, folks, please help...

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Life and love are mixed with pain...

[Roger Clark]

Ray,
I've never heard of the Monza having split propshafts. Pomeroy in the GRand Prix CAr says merely that the chassis was entirely conventional. The propshafts of the Tipo A and B (P3) were regarded as so novel that I am sure it would be well documented if the Monza had them too. In any case the Monza was based closely on Alfa's sports of the sday and is unlikely to have had such sophistication.
As far as the Tipo A's is concerned, I always thought that the engines were independent of each other and not geared togeher except through the medium of the back axle. THat would allow the engines to be started independently and would ensure that they ran at the same speed as long as the car was in gear (both gearboxes!)
Incidentally, I believe that the Bimotore had similar final drive arrangements to the Tipo A and P3. Now that was a car with a lot of propshafts!

[Art]

Ray Bell.

The only reasoning I can see for the split drive shaft is. To lower the drivers seat extra gears weight one hell of a way to add ballast. If the rear end wasn't one piece it would of put the weight of each rear end on the wheels or un sprung weight. Aw hell I don't know what i'm talking about.

Art NX3L

[Ray Bell]

How's your nurse?
It did not lower the driver! It was all to do with traction...
How's your nurse?

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Life and love are mixed with pain...

[Ray Bell]

I wonder if the Monzas adopted the split drive after first coming with the normal diff. Or if Alfa made them an option.
Certainly, I knew nothing about the drive arrangement until Alf Barrett described it to me, and he was talking about his Monza after he'd crashed at Lobethal...

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Life and love are mixed with pain...

[Art]

Ray Bell.

Hows the Nurse? She's just humpin and a pumpin.

Art NX3L

[Ray Bell]

I called Barrett's brother tonight and confirmed that the rear end of the Monza was standard, ie. not split - but I'm still looking for a drawing of the Tipo A rear end.

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Life and love are mixed with pain...

[Art]

Ray Bell.

I have your answer. The torque reaction of two counter rotating drive shafts would force the wheels to the road equally. A single drive shaft would have torque reaction to lift one wheel and plant the other one to the road more firmly.

Art NX3L

[Ray Bell]

That's absolutely right, Art - but that's not how it was in the P3. That's the mystery I'm trying to solve - why not cancel out the forces that are detrimental to traction?

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Life and love are mixed with pain...

[Art]

Ray Bell.

Forces detrimental to traction? Lack of grip from the tires. To Much power applied to quickly? = Nutralize torque and a driver with an educated throttle foot. Don't forget this is back in the 1930s maybe the answer you are looking for didn't exist then? It wouldn't be the first time a desiner did some thing that didn't make sense.

Art NX3L

[Art]

Ray Bell.

Some thing to think about. Traction controle are there other ways than 1.Drivers Foot 2.Electronic Traction Controle 3.Mechanical Traction Controle 4. A Slipper Clutch?

Art NX3L

[Art]

Ray Bell.

on a picture I found of the Alfa Monza. The Picture taken from the rear downward into the cockpit shows a straight narrow tunnel in the flor pan running straight back. And in Dennis Davids article on the P3 it shows a cut away of the car and says(the split drive shaft was used to lower the drivers seat)Take it for what it is worth??

Art NX3L