27 replies to this topic

[Megatron]

What was the first F1 car to make the engine a stressed member of the car instead of just droping it in the chassis?

I think it might be the Lotus BRM of 1966, but I am not sure.

[Don Capps]

Actually, Vittorio Jano (telaio) & Ettore Zaccone Mina (motore) teamed up for probably the first use of the engine as a stressed member of the car. It was the Lancia D50 of 1954....

[mono-posto]

Though the Lancia D50 was very innovative in it's use of utilizing the engine as a load bearing element, it did not do so completely. There was still a tubular from that ran under the engine to support it.

The first F1 car to use this concept completely (with the engine as a fully stressed member) was the Ferrari 158
in 1964, both in V-8 and flat-12 configurations.

Ferrari gave up this concept for the 1966 car, returning to a more traditional design, while Colin Chapman adopted it in 1967 with the Lotus 49.

Ferrari returned to this design with the 312B in 1973 it has been widely practised since.

[Alfisti]

What on earth is a "stressed" part of the car???

[Darren Galpin]

As I understand it, an engine is stressed if the engine forms part of the structure of the car through which all forces pass. The engine is not simply bolted in and left to hang - things like suspension stresses will get transmitted through it.

[Roger Clark]

Although the D50 did have a tubular frame under the engine, I believe it was only there to stop the car from falling apart when the engine was removed. It did not bear any significant stress when the car was driven.

The Ferrari 158 had a tubular frame, but the 1512 did not. The 158 was originally designed on the frameless principle, but the engine was delayed and the chassis first appeared at Monza in 1963 with the V6 engine. The V6 was not sufficiently rigid to bear all the loads, so a sub-frame was added. When the V8 appeared in 1964, it also was found to be insufficiently rigid and retained the sub-frame.

Either way, Ferrari started the trend.

[Don Capps]

Roger is correct about the tubes running under the Lancia engine, their purpose was simply to allow the fore & aft sections of the machine to stay connected when the engine was being replaced or the engine was out of the car for whatever reason. They were not a stressed part of the chassis like the engine. Also, correct on the Aero 156 & 158 cars, the engine not being able to take the stress of being a load-bearing member of the machine, hence the substructure for the engine.

It wasn't Ferrari who started the trend, but Lancia...

BTW, ever notice that some reason Jenks never seemed to really like the Lancia D50? I always get the impression that Jano or Lancia must have tweaked DSJ's beard or something similar.

[Roger Clark]

Don,

i suppose it depends on your definition of a trend, but nobody followe Lancia for 10 years, so I would still give Ferrari the credit. It's interesting that as soon as Ferrari got th D50s he installed chassis tubes around the engine.

I can't say I had noticed any anti-D50 feeling from DSJ, but I wouldn't be surprised, particularly in 1956. He did have a trident engraved on his heart.

[Don Capps]

Roger,

On Target as far as giving Ferrari due credit for clicking on the "Aha!" Light as to using the engine as an integral part of the machine. While they didn't quite get it right on the first shot, the idea was soon copied by others.

Jenks was not an impartial observer and you are correct that he was a big fan of the Maserati and Vanwall teams. He simply didn't care for Lancia for some reason, perhaps it was for something so trivial that we'll never even fathom the why even if we were to know.

I think the D50 often gets lost in the shuffle since the spotlight is usually on the W196 and the 250F. And how many can even recall the Gordini efforts of the day?

[luisfelipetrigo]

Alfisti:

I suggest you buy an F1 model kit (tamiya or similar) and put it together. Doing so will, in addition to some hours of enjoyment, give you a very good illustration of how the engine/gearbox is a stressed part of the rest of the car.

[John Cross]

Let's not forget that Bugatti mounted his engines rigidly to increase the stiffness of the chassis in the 1920s - he was surely the first to use the engine as a stressed member (in the sense of taking external loads fed in from the chassis). His cars (like the T35) had a reputation for fine handling, and I think this was one of the reasons.

[Don Capps]

John,

I think you have a good point there. The block was used for providing some rigidity in the 35 & 39 series, but I am unable to recall the level obtained and the effect on handling. I will try to see what I can find in Conway or from some of the other Usual Bugatti Suspects...

[John Cross]

Don,

Pomeroy says that:

Torsional strength is even more important in frame design than beam strength. The Bugatti frame in itself is not very good in this respect, but the car as a whole is exceedingly rigid. The two dumb-irons are tied together by a tube, whilst the straight-eight engine, being rigidly mounted at four points, ties up the entire front part of the frame in an admirable fashion. The back part of the frame is stiffened by transverse tubular memebers,...

No figures here, but clearly the engine is contributing a lot to the rigidity of the chassis. BTW, Pomeroy should really be referring to stiffness rather than strength as important factors.

[Alfisti]

Originally posted by luisfelipetrigo
Alfisti:

I suggest you buy an F1 model kit (tamiya or similar) and put it together. Doing so will, in addition to some hours of enjoyment, give you a very good illustration of how the engine/gearbox is a stressed part of the rest of the car.

I tried to put together a Giulietta model and the body work turned out even worse than Alfa's usual standard. I guess i'm just not cut out for it.

[Huw Jenjin]

The use of the word "stressed' is not really in keeping with what is meant when it is used with regard to vehicle design.
in truth it is unlikely that any engine in any vehicle is unstressed. It is unlikely that any vehicle where the engine is bolted directly to the body or chassis is unstressed.
The point is, "Is the engine structural or not."

in the case of the D50, Yes it is clearly structural, but not totally stuctural.
in the case of a Vincent or Ducati motorcycle, or racing car post Lotus 49, theengine is fully structural, in that if it was taken away, the vehicle would cease to act as a single entity, or Structure.
Whoever dreamed up "Stressed member" would probably call a spade a semi metallic displacement instrument.

[John Cross]

Huw,

Clearly the engine plays a more significant role when it is actually replacing parts of the chassis. Nevertheless, the original query was about using the engine as a stressed member (ie accepting and resisting forces external to the engine), rather than being mounted in such a way as to minimise the external forces. The Bugatti engine was clearly mounted in such a way, and so the T35 was the first such car.

[Roger Clark]

The 1914 Mercedes also used the engine to add stiffness to the chassis, there may well have been others. It's all a question of degree..

As far as I know, the D50 was the first car in which the engine was the major structural component.

[desmo]

Doesn't this year's Jordan have a sub-frame which transfers a portion of the chassis loads from the rear suspension to the tub thus bypassing the engine? I would think that any rigidly mounted engine carries chassis loads and could be characterised as a stressed member. Perhaps I am digressing into semantics.

[Don Capps]

I took a quick look at my 35/39 Bug Notes last night and still working on some of the specifics about the use of the engine as a part of the stessing of the chassis. It seems I got distracted when I noticed something about a chassis number and....

As a clarification on Jenks & Lancia, I am now very confused. I forgot that Jenks owned an Aurelia in the mid-50's and spoke very highly of it, so perhaps it wasn't Lancia per se, but either just the D.50 of Jano...

[John Cross]

Roger,

You're quite right - Pomeroy says:

...the bottom half (of the engine) was merely an oil container, all the stresses being taken through the upper half which also acted as a considerable stiffening element in the front end of the frame.

The frame was also stiffened by an X-bracing member just aft of the gearbox, a cross member under the radiator, to some extent by the gearbox, and a couple more members at the rear.

By contrast, the 1912 Peugeot engine was carried in a sub-frame attached to the chassis by ball and socket joints at the back and a trunnion bearing at the front. The engine was thus isolated from any strain imposed by the chassis.

[Ray Bell]

Oh I wish I had taken note at the time.... when I had the opportunity to have a good look at the 1919 Indianapolis Ballot.... it had a separate chassis (as in the Peugeot mentioned above) for the engine, but if this was bolted solidly in place (the bit I didn't note) and if the engine was solidly bolted to it, this would have predated the Bugatti.
Shall I just mention again the 1955 Eclipse Zephyr? This used the Ford Zephyr 6 engine as a section of the chassis, linking the Holden front crossmember to the tube that located the Tempo Matador transaxle some distance behind the clutch housing. The rear suspension was bolted to the transaxle and the only other chassis components were light bits and pieces that supported seats, pedals, fuel tanks and bodywork.
As for the term 'stressed member'... the engine in this was stressed in that it took chassis stresses as well as engine stresses. Perhaps the term should be 'double stressed members'?

[Kaha]

Originally posted by Don Capps
I took a quick look at my 35/39 Bug Notes last night and still working on some of the specifics about the use of the engine as a part of the stessing of the chassis. It seems I got distracted when I noticed something about a chassis number and....

As a clarification on Jenks & Lancia, I am now very confused. I forgot that Jenks owned an Aurelia in the mid-50's and spoke very highly of it, so perhaps it wasn't Lancia per se, but either just the D.50 of Jano...

As the Aurelia was very much a Jano car, it probably was not Jano that Jenks didn't like.

[oldtimer]

A comment on the Jenks thing. The D50 took a long time to make its racing debut in 1954 after being expected to be ready for a whole season of racing. I don't think Jenks was anti Lancia or Jano. But it is obvious from his other writings that he was never impressed by 'promised' performance. And that went for the Vanwalls too. He was a 'put up or shut up' observer.

In his Racing Car Review for the 1954 season, Jenks writes of the two small tubes at the connecting the bottom of the chassis to the front suspension structure. He goes on: Between the cockpit bulkhead and the top of the front suspension cross-members the engine was situated, and on the four corners of the unit were cast-in lugs and the engine was bolted to the two main frame structures, thus using the the strength of the engine castings as the top tubes for a full space frame. An accompanying photograph shows two of the lugs on the RHS of the engine, situated between the camshaft covers.(my emphasis)

Jenks does not write of any lugs on the crankcase of the engine. Were there any, or is he correct in writing that the engine completed only the top of the chassis space frame?

[Roger Clark]

My understanding was that the bottom tubes were only there to stop the car falling apart when the engine was removed, and didn't take any significant load when the car was running.

[bobbo]

Don:

Maybe this is a bit OT (or should it start another?? I don't know.), but I, like you, would like to hear a bit more about the DSJ/Jano/Lancia/Ferrari thing.

Anyone else have any input??

Thanks!!

Bobbo

[oldtimer]

So, has anyone seen a photo of the D50 engine outside of its chassis, and does it show lugs on the crankcase?

In his Racing Car Reviews, Jenks would give technical descriptions of the cars appearing in F1 events for the year, and short accounts of their performances in each event they appeared. They were DSJ accounts, so if the performances impressed him he said so, and if they did not impress him, he said so too.

In his review of the 1954 season, clearly Jenks was disappointed by the non-appearance of the D50s, since there were several indications that this was to be a major effort. He was impressed by their speed in the Spanish GP, but not by the retirement of both cars by 10 laps. "In only 10 laps the two Lancias were withdrawn and while many people might be tempted to consider the first appearance of these new cars as a rather poor effort, it must be agreed that while the car was running it was a long way in advance of its rivals."

Ascari's retirement is described as a rather lethargic affair, and Jenks writes 'that the official reason for retirement was given as clutch trouble'. Reading between the lines, and remembering that Jenks could only give second hand hints about handling problems during earlier testing, I wonder if Lancia were not so willing as some others to allow Jenks to snoop around in his accustomed way.
There are examples of Jenks reporting 'official' reasons for retirement, followed by a comment on his own observation. Following a BRM retirement: 'The official reason for retirement was given as loss of oil pressure. This was probably on account of the large hole in the block.'

In his 1954 review, he observed that the car needed a lot of wheel-winding, and he describes the handling problems in more detail in his 1955 review. But he gives praise where was due, as in the Turin GP, where Lancia beat both the Ferrari and Maserati teams, and less praise when less praise is due as in their win over the Maserati team in the Naples GP. Seems like normal DSJ to me.

Remember he had an inside track at Mercedes, Maserati and Vanwall as a participant in the team efforts. No wonder he got excited, both as an enthusiast and a journalist.

[dbw]

design patent issued may 4 1920..#55,070..to h.a. miller, shows a race car design[later embodied as the t.n.t.] clearly showing the front suspension mounted on the front of the engine,with the engine itself acting as the stressed extension of the chassis...[dee's "miller dynasty"]

[Roger Clark]

Bobbo,

I thinkI said earlier, I didn't recognise the anti-Lancia feeling by Jenkinson which Don reported.