40 replies to this topic

[Mark 13]

I have been disturbed over recent seasons about not seeing the louder V16 at the likes of the Goodwood FOS. I think it is now owned by that nice Mr Ecclestone. I hope we can see it again very soon and even better alongside the 2 Mk 1's.

[simonlewisbooks]

Originally posted by Mark 13
I have been disturbed over recent seasons about not seeing the louder V16 at the likes of the Goodwood FOS. I think it is now owned by that nice Mr Ecclestone. I hope we can see it again very soon and even better alongside the 2 Mk 1's.

Is this one of the Donington Collection cars which Mr E has aquired ? Didn't Donington put another at least one more Mk2 together from bits some years ago and commission some replica engines? Maybe I'm just imagining it.

Years back Nick Mason demo'd his Mk2 at Castle Combe and my brother, Dad and self were working on our Rover 220 when this thing burst onto life early in the day...instant silly grins all round!
The V16 was warmed up by doing several slow laps of the paddock whooping and shrieking away before being backed into position alongside the GTO and a Lotus 49 by the control tower. A big crowd was already gathered and when the engine was given one final whoop and turned off the assembled masses spontaneously burst into applause! It was one of those lovely moments.

[Dutchy]

I believe it was a Mk I that Donington put together fairly recently (the light green one). The Mk IIs are both original cars; one was owned by Donington and the other by Nick Mason. I imagine it's the latter that BE now has.

[David Beard]

Originally posted by Mark 13
I have been disturbed over recent seasons about not seeing the louder V16 at the likes of the Goodwood FOS. I think it is now owned by that nice Mr Ecclestone. I hope we can see it again very soon and even better alongside the 2 Mk 1's.

I didn't know the Mk1 & 2 made different noises. Why would that be?

[Allan Lupton]

Originally posted by David Beard


I didn't know the Mk1 & 2 made different noises. Why would that be?

Original cars had proper exhaust pipes (2 or 4) but in "recent" times I've seen stub exhausts. Don't know which mark has them now, but I think it was a Mk2 I saw thus equipped
That may be the reason.

[simonlewisbooks]

Originally posted by Allan Lupton

Original cars had proper exhaust pipes (2 or 4) but in "recent" times I've seen stub exhausts. Don't know which mark has them now, but I think it was a Mk2 I saw thus equipped
That may be the reason.

Yep the Mk2 with stub-exhausts is a bit like a top fuel dragster. It really spits out the decibels while the conventional tail pipes of the Mk1 smoothed out that noise just a little. In either case there in no mistaking the engine producing all that glorious volume.

Simon Taylor in his recent track test of a Mk2 said that because the stubs all pointed away from the driver it didn't sound quite as earsplitting from the cockpit as he was expecting. I guess that very much a relative term!

I think that article quoted the engine rating at about 625bhp or thereabouts. To think that the F1 Turbo cars of similar size didn't reach that figure untill 1982/83... amazing.

[Henri Greuter]

Originally posted by simonlewisbooks


Yep the Mk2 with stub-exhausts is a bit like a top fuel dragster. It really spits out the decibels while the conventional tail pipes of the Mk1 smoothed out that noise just a little. In either case there in no mistaking the engine producing all that glorious volume.

Simon Taylor in his recent track test of a Mk2 said that because the stubs all pointed away from the driver it didn't sound quite as earsplitting from the cockpit as he was expecting. I guess that very much a relative term!

I think that article quoted the engine rating at about 625bhp or thereabouts. To think that the F1 Turbo cars of similar size didn't reach that figure untill 1982/83... amazing.

I doubt that figure of 625 hp very much. I have read about 545 to which I think could be right on the few occasions that all 16 cylinders worked properly. Which, from what I've understood, happened very, very rarely. In 1951 The Alfetta 159 could be persuaded to produce 425 hp but if it did, it almost drowned in methanol to keep cool enough. That the BRM could produce some 200 hp more looks very, very unlikely to me. That 625 figure appears to me as just about everything else that was related with the BRM: way too optimistic.

Henri

[simonlewisbooks]

Originally posted by Henri Greuter



I doubt that figure of 625 hp very much. I have read about 545 to which I think could be right on the few occasions that all 16 cylinders worked properly. Which, from what I've understood, happened very, very rarely. In 1951 The Alfetta 159 could be persuaded to produce 425 hp but if it did, it almost drowned in methanol to keep cool enough. That the BRM could produce some 200 hp more looks very, very unlikely to me. That 625 figure appears to me as just about everything else that was related with the BRM: way too optimistic.

Henri

Henri I confess that is the first time I have seen this figure quoted . Simon Taylor doesn't seem to me the kind of writer to pluck a figure from thin air so as the car has been rebuilt and fettled over recent years by a very skilled team it could be that with pistons, bearings, valve springs and other components used today - no doubt of far better quality than those of the car's prime years - they have actually have produced this figure in recent dyno tests? It wouldn't be the first restored engine of this era to produce more power in it's old age than in it's youth.

Maybe Doug Nye can confirm?

[Robin Fairservice]

In Tony Rudd's book "It Was Fun" on page 70 he quotes 585 bhp at 11,000 rpm, and 612 at 11,500, when it blew with a thunderous backfire. This was on February 22, 1953 and the chart is reproduced. Graham Hill did a demonstration at Kylami in 1968 and put the rev counter off the clock at 12,500 rpm (page 80). Tony estimated that the power output was 780 bhp!

[Henri Greuter]

Originally posted by Robin Fairservice
In Tony Rudd's book "It Was Fun" on page 70 he quotes 585 bhp at 11,000 rpm, and 612 at 11,500, when it blew with a thunderous backfire. This was on February 22, 1953 and the chart is reproduced. Graham Hill did a demonstration at Kylami in 1968 and put the rev counter off the clock at 12,500 rpm (page 80). Tony estimated that the power output was 780 bhp!

I think the engineers on the pioneering turbo F1 engines (Renault, Ferrari, BMW) should be ashamed of themselves that it took them so long to before they produced similar figures if this is really true.

But then, of course, there is a difference in the fuels used by the BRM and the straight pump fuel of the late 70's and 1980, 1981.

And besides that, dyno hp's are not always comparable with what the car had. I recall Roberto Guerrero telling in 1990 that he had seen the power outputs on the dynos of the Alfa Indy V8 of 1990 which, if true. were close to what the ChevyA had. But he then told that, somehow, when installed in a car then that power was never there and it felt as if the engine was not capable to produce that power anymore. As if dyno conditions were not comparable with the car conditions anymore.


Henri

[simonlewisbooks]

Originally posted by Henri Greuter


And besides that, dyno hp's are not always comparable with what the car had.
Henri

But thats an installation issue rather than a fault with the engine. F1 history is littered with those.

[Henri Greuter]

Originally posted by simonlewisbooks


But thats an installation issue rather than a fault with the engine. F1 history is littered with those.

Something to say for that.
But the V16 was one big mistake to begin with.
Though, it is a nice mistake nowadays.

In fact, I think that for the sake of history and pleasue it is a good matter that some mistakes were made and were kept running nonetheless. The BRM being one of them.

Another classic example: the Novis. With hindsight they were not the favorites many thought they were. One could even argue why they have ever been built, the Front Wheel Drives in particular.
But take the efforts of the FWD Novis away from Indy history 1946-1955 and a lot of excitement and spectacular things that were memorable are gone. They made Indy history like few cars did in that period of time. Indy 1946-1955 without the Novis would have been a different era, maybe not results wise but totally different headlines for the newspapers then and different chapters within the books about that era.....


Henri

[simonlewisbooks]

Originally posted by Henri Greuter


Something to say for that.
But the V16 was one big mistake to begin with.
Though, it is a nice mistake nowadays.

In fact, I think that for the sake of history and pleasue it is a good matter that some mistakes were made and were kept running nonetheless. The BRM being one of them.

Another classic example: the Novis. With hindsight they were not the favorites many thought they were. One could even argue why they have ever been built, the Front Wheel Drives in particular.
But take the efforts of the FWD Novis away from Indy history 1946-1955 and a lot of excitement and spectacular things that were memorable are gone. They made Indy history like few cars did in that period of time. Indy 1946-1955 without the Novis would have been a different era, maybe not results wise but totally different headlines for the newspapers then and different chapters within the books about that era.....


Henri

Absolutely agree with you Henri. Glorious fiascos and misadventures are often far more exciting and interesting than something done with clinical perfection. Maybe thats one of the reasons so many of us no longer car for F1?
Not enough mad things happen on track these days...it's all in the motorhomes and boardrooms!

And although it may have sounded like I have been defending the V16, I agree that it was a fundamentally flawed design. Far too complex for the times and the technology. But glorious in it's way.

[Sharman]

Or flats off the Bayswater Road

[fines]

Too true, Henri!

The V16 BRM, the Novi, the "Big Six" Thorne-Sparks, the Tyrrell P34, all those glorious failures: it's far too easy to explain why they didn't work, but blessed us, thankfully there were still people who built'em!

[Mark 13]

Originally posted by simonlewisbooks


Absolutely agree with you Henri. Glorious fiascos and misadventures are often far more exciting and interesting than something done with clinical perfection. Maybe thats one of the reasons so many of us no longer car for F1?
Not enough mad things happen on track these days...it's all in the motorhomes and boardrooms!

And although it may have sounded like I have been defending the V16, I agree that it was a fundamentally flawed design. Far too complex for the times and the technology. But glorious in it's way.

It seems to be a common view that the V16 was too complex for the time but it was working well by the time it became obsolete. I think the issue was the use of twin superchargers, designed for aircraft where higher sustained speed was the main objective. By constantly chiming in and out the engines probably failed to run cleanly. Clearly the number of components would also create a greater number of potential problems.

The exhaust issue is interesting as the convential pipes on the Mk 1 were replaced by the stubs for the Mk 2 which was altogether a more compact machine. The noise is phenomenal and I have missed it over the past few seasons. Sadly i am a noise junky and I have been making do with Drag Racing, Heavy Metal and small block Chevy's (T70's) for my fix in recent times. I think we are due for anorther celebration of BRM just so we can wheel out all the V16's in one place.

[Allan Lupton]

Originally posted by Mark 13

I think the issue was the use of twin superchargers, designed for aircraft where higher sustained speed was the main objective. By constantly chiming in and out the engines probably failed to run cleanly. Clearly the number of components would also create a greater number of potential problems.

The two-stage (not twin) centrifugal supercharger was certainly inappropriate, but not for the reason you state.
The pressure delivered by such a device goes up as the square of the rotational speed, which was to have been controlled by a system of "vortex throttles" which were not developed. As a consequence the power curve of the engine was very steep, and without a real peak in the useable (or even emergency) rev. range which made the car very difficult to drive.
I'm not sure what you mean by "constantly chiming in and out" unless that's a reference to the noise which results from varying the power in response to wheelspin, etc.

Aeroplane engines operate much of their time at constant power settings so power curve characteristics are not as important as for a wheel-driven vehicle.

(only a quick, brief response: the whole thing has been written up properly many, many times elsewhere)

[simonlewisbooks]

Originally posted by Allan Lupton

The two-stage (not twin) centrifugal supercharger was certainly inappropriate, but not for the reason you state.
The pressure delivered by such a device goes up as the square of the rotational speed, which was to have been controlled by a system of "vortex throttles" which were not developed. As a consequence the power curve of the engine was very steep, and without a real peak in the useable (or even emergency) rev. range which made the car very difficult to drive.
I'm not sure what you mean by "constantly chiming in and out" unless that's a reference to the noise which results from varying the power in response to wheelspin, etc.

Aeroplane engines operate much of their time at constant power settings so power curve characteristics are not as important as for a wheel-driven vehicle.

(only a quick, brief response: the whole thing has been written up properly many, many times elsewhere)

Agreed, it was a system that worked OK on Millers at Indy where high revs were sustained but for road racing iit left the driver with a fairly violent on-off power delivery which made the handling pretty evil in long fast corners. Moss said it wasn't possible to hold the revs and get the car to balence in a conventional four wheel drift - the fastest way round a corner in the 1950s,because the revs were always climbing or falling very quickly.
Interestingly he test-drove a Brabham BMW Turbo at Brands in 1983 (featured in AUTOMOBILE SPORT) and said that engine reacted in much the same way - the turbo using a similar centrifugal-type compressor to that on the BRM (though smaller). The grip level of the 1983 car however meant it didn't suffer the same kind of handling ailments. Four wheel drifts had been replaced by 'driving on-rails' to a large degree.

[Roger Clark]

Originally posted by Henri Greuter



I think the engineers on the pioneering turbo F1 engines (Renault, Ferrari, BMW) should be ashamed of themselves that it took them so long to before they produced similar figures if this is really true.

You also need to remember that the BRM would have needed at least 200 bhp to drive the supercharger.

[Henri Greuter]

Originally posted by Roger Clark

You also need to remember that the BRM would have needed at least 200 bhp to drive the supercharger.

I know that the supercharger consumed power. Don't know if it was 200 in the case of the BRM. The only value I know about centrifugal supercharges requiring is that on the Grantelli owned Novis (early 60's) tyhey estimated the power loss to the supercharger some 75 hp. And those engines were claimed to be between 640 and 740 hp in that era. (for they who don't know the Novi: 3 liter, later 2.8 liter V8, centrifugally supercharged)
The prewar mercedes 3 liter V12 was rated at 135 hp or thereabout for blower driver but that was a single rootsblower.

If I understand all the figures for the BRM correct then on one occasion it was rated to produce over 700 hp. was that with or without the drive to the supercharger?

Amazing engine for sure. But too much at the time for too less of an organisation.

henri

[simonlewisbooks]

Originally posted by Roger Clark

You also need to remember that the BRM would have needed at least 200 bhp to drive the supercharger.

This is one of those areas I think gets greatly misunderstood but widely quoted.

Yes it may take a 200bhp engine to drive the BRM's blower, as a stand alone unit at full revs, but the figure seen on a dyno is for the complete engine including driving the blower, oil pumps, cams etc. It's the 'end product' of all this.

W O Bentley often mentioned in his writings how much power the Birkin Blower "consumed for itself" but he had a very strong objection to the whole concept , he just didn't like superchargers and he didn't like what Birkin was doing so would never waste a chance to decry it . A blown 4.5 still put out a lot more power than an unblown one whether he liked it or not.

[David Beard]

Originally posted by Roger Clark

You also need to remember that the BRM would have needed at least 200 bhp to drive the supercharger.

Where do you get that from, Roger? Sounds an awful lot.

[Robin Fairservice]

It would be possible to calculate the probable horse power requirement knowing the rate of of air flow through the unit, the pressures at the inlet and outlet, and inlet and outlet temperatures, but I am not going to attempt it. There would also be some friction losses and drive efficiencies to allow for.

[Robin Fairservice]

Replying to my own message, I realised that it would be possible to estimte the gross engine horse power from the BMEP (Brake Mean Effective Pressure) so I went looking. In the book V 16 I found a chart with a number of 420 psi at 10,000 rpm, and calculated an Indicated Horsepower of 959. Tony Rudd's graph gives 578 bhp at 10,000 rpm, so the blower could have been absorbing 381 horse power. I can't remember the difference between IHP and BHP, so the 381 is probably a bit high.

[Allan Lupton]

Originally posted by Robin Fairservice
Replying to my own message, I realised that it would be possible to estimte the gross engine horse power from the BMEP (Brake Mean Effective Pressure) so I went looking. In the book V 16 I found a chart with a number of 420 psi at 10,000 rpm, and calculated an Indicated Horsepower of 959. Tony Rudd's graph gives 578 bhp at 10,000 rpm, so the blower could have been absorbing 381 horse power. I can't remember the difference between IHP and BHP, so the 381 is probably a bit high.

BMEP, as its name implies, is a derivative figure based on the torque measured on the brake (dynamometer).
It would not be possible to calculate an ihp from it as the brake figure must be nett of blower drive etc.
Also don't forget that N in the PLAN/33000 formula is the number of power strokes/minute so the bhp that goes with a bmep of 420 psi at 10,000 rp. is about 480

[Doug Nye]

Interesting thread...

DCN

[Robin Fairservice]

I can't find my little book of engineering formula, but last night on Wikipedia, I found some formula that included BMEP, and that indicated that BMEP was calculated from torque. Using the formulae on that link and 420 psi I got 477 bhp for the engine, which doesn't agree with Tony Rudd's dyno chart. I have vague memories of measuring BMEP on a natural gas engine in first year Thermo-dynamics, but perhaps 50 year old memories are not reliable!

The question of how much power does a two stage centrufugal supercharger absorb is still fascinating and unanswered.

[Allan Lupton]

Originally posted by Robin Fairservice
I can't find my little book of engineering formula, but last night on Wikipedia, I found some formula that included BMEP, and that indicated that BMEP was calculated from torque. Using the formulae on that link and 420 psi I got 477 bhp for the engine, which doesn't agree with Tony Rudd's dyno chart. I have vague memories of measuring BMEP on a natural gas engine in first year Thermo-dynamics, but perhaps 50 year old memories are not reliable!

As I wrote, above. . . Glad to see that wikipedia, the fount of all erroneous knowledge, must have got that bit right!
My time in the Thermod. lab at Hatfield Tech is also about 50 years ago, but we actually had an indicator on our gas engine so claimed to be able to calculate ihp directly(!). With the hit-and-miss governor on those things, you had very little chance.

The question of how much power does a two stage centrufugal supercharger absorb is still fascinating and unanswered.

As noted above, there are a lot of unknowns in the calculation which would make it quite hard. (such as mass flow, inlet and outlet temperatures as well at pressures (the latter were approx. 1 atmosphere and 5.7) efficiency coefficients, etc.)
I have seen a figure of "up to 400 hp" required to drive the supercharger on a R-R Merlin, but can't find a definition of which Merlin/supercharger or what regime. The highest boost pressure used in the Merlin was 25 psig, as the purpose of the supercharging was more to restore sea-level power at altitude than to increase the maximum power (which it also did).
If you want to compare that to the BRM, it's about 30% of the pressure ratio; the crankshaft speed is about a third, and the displacement is about 18 times. . . .

[fuzzi]

Have a look at the Technical Forum (next door) and bring up

WW2 Piston Aero Engines and BMEP (just type in "Dago Red" to Search BB) and apart from solid technical information you'll find some serious horsepower and links to see some very powerful engines

[Allan Lupton]

Originally posted by fuzzi
Have a look at the Technical Forum (next door) and bring up

WW2 Piston Aero Engines and BMEP (just type in "Dago Red" to Search BB) and apart from solid technical information you'll find some serious horsepower and links to see some very powerful engines

and some quite poorly informed calculations!

[Robin Fairservice]

A fascinating read. I noted a reference to the Napier Sabre engine. A friend was an RAF fighter pilot and he had flown the Tempests and Typhoons fitted with this engine. The later version of these two aircraft had contra rotating props, and he reckoned that it was a fabulous plane to fly.

[simonlewisbooks]

Originally posted by Doug Nye
Interesting thread...

DCN

Do I detect a wicked smirk Doug?

[RaymondMays]

Originally posted by Mark 13
I have been disturbed over recent seasons about not seeing the louder V16 at the likes of the Goodwood FOS. I think it is now owned by that nice Mr Ecclestone. I hope we can see it again very soon and even better alongside the 2 Mk 1's.

Back to the original subject of this thread, I hope that if anyone does get wind of an appearance by a V16 at any event, they publicise it well here. I haven't seen one in action since the BRM 50th Anniversary celebrations in Bourne.

[D-Type]

Originally posted by Robin Fairservice
A fascinating read. I noted a reference to the Napier Sabre engine. A friend was an RAF fighter pilot and he had flown the Tempests and Typhoons fitted with this engine. The later version of these two aircraft had contra rotating props, and he reckoned that it was a fabulous plane to fly.

I don't think the Typhoon/Tempest ever had contra-rotating propellors. Some late model Typhoons had four-bladed props instead of the usual three-bladed one which could be what your friend was recallig - a minor error after 60+ years.

[Allan Lupton]

Originally posted by D-Type
I don't think the Typhoon/Tempest ever had contra-rotating propellors. Some late model Typhoons had four-bladed props instead of the usual three-bladed one which could be what your friend was recallig - a minor error after 60+ years.

Bit OT, but . . .
So far as I know, the Sabre was never fitted with contra-props (nor was the Centaurus, also found in Tempests). Quite why that was is hard to understand as the torque effect on take-off would have been quite worth eliminating.

[Robin Fairservice]

I can never remember the order of the Tempest and Typhoon, but the first one had a 16 foot diameter propeller, and when taking off and landing it was tricky not to hit the runway with it. My friend (who was married to the model for the Daily Mirror's Jane!) said that he had to have both feet on one side of the rudder bar to keep the plane straight on take off. The second one had 12 foot diameter contra rotating props and was much easier to take off as there was no torque and more clearance. I later met another ex. RAF fighter pilot who had the similar comments.

Wikipedia however, says that the Typhoon was first with a three bladed prop and the Tempest came next with a four bladed prop. My friends memory must have been at fault.

I think that we are way off topic now!

[Philip Whiteman]

Here's the answer from the horse's mouth: I have 'Supercharging the 1 1/2-litre V.16 BRM Racing Engine', the 1964 Institution of Mechanical Engineers paper by Wilde and Allen, open on my desk in front of me. This publication deals with Rolls-Royce's involvement in developing the BRM supercharger up until 1952, when their involvement ceased.

It's all there in black-and-white – if you can work your way through the various equations and graphs! (I do remember from BP research days that Power equals PLAN, where P is break mean effective pressure, L is stroke, A is piston area and L is number of firing strokes per second – I think… All a long time ago!)

The V16 engine started out with a 3.25:1 step-up ratio between crankshaft and supercharger speed. Due to the deletion of the vortex throttles and the substitution of SU carburettors for the planned fuel injection system, which spoiled 'driveability', made for poor fuel distribution and reduced airflow, the ratio was increased to 4.0:1 to increase boost pressure in an effort to find more power. The published dyno measurements show the engine to have developed around 385hp at 9,000 rpm, with 450hp projected at 10,000 rpm. A line on the graph shows supercharger horsepower hitting a maximum of 150hp at 10,000 rpm – about double the power consumption when driving the supercharger at 3.25:1. The authors say '[it was] clearly becoming uneconomic to increase the supercharger speed much further'.

The 500hp figure you see quoted for the BRM V16 came later in the engine's development, but I don't think any further change was made to the supercharger (Doug?)

I was lucky enough to meet Geoffrey Wilde in the late 1990s, when Messerschmitt 109G 'Black 6' was being flown at Duxford for a Robbie Coltrain TV show. I asked him what he thought of Daimler-Benz's aero-engine superchargers: "Not much," he said. They'd actually run one on their own test stand in the 1940s, having recovered it from a 109 that crash-landed in the Thames estuary. But now I'm going off-topic again…

[Allan Lupton]

Originally posted by Philip Whiteman
A line on the graph shows supercharger horsepower hitting a maximum of 150hp at 10,000 rpm – about double the power consumption when driving the supercharger at 3.25:1. The authors say '[it was] clearly becoming uneconomic to increase the supercharger speed much further'.

I do not think that the curve of power required to drive the supercharger would have a maximum point - I guess the line just stopped at 10,000 rpm. The power would be roughly proportional to the cube of the speed, and the 200 hp quoted above (Roger Clark) wouldn't be far adrift (even a bit low) at the higher rpm that were used.

[GeoffE]

Originally posted by Robin Fairservice
the model for the Daily Mirror's Jane!

Sorry to drift off topic but in the 1970s that used to be said about a lady in Cheltenham, who sported a large blonde wig and pushed three white poodles around in a pram. Same woman?

[Philip Whiteman]

Yes; the curve stopped at 10,000 rpm, at which the supercharger was absorbing 150hp. And yes; extrapolation of the curve by eye suggests between 200 and 300hp at 11,000 rpm.

[Robin Fairservice]

I don't think so as they lived in Horsham in the 1960's and 70's, when I knew them. Of course there might have been more than one model for a long series of cartoons,