Formula One Engines

I think the teams already use the highest density material allowed by the sporting regs. I think you are correct in your assumption that there are ways to reduce drag on the crankshaft, but even with excellent windage trays and crank scrapers, the crankshafts are still operating in a moving slurry of oil and air and I am not sure what the best aerodynamic shapes are for that environment. I do know that counterweight shape is something that is worked on at all levels of motor sports including the Saturday night hobby stock racers.

Today's rules for F1 crankshafts do prohibit the use of exotic materials to cut cost. However, I was surprised to find this picture of a 2000 Ferrari crank:

The speed of the counterweights at 18,000 rpms or more is tremendous, and I would think that the flat leading edge of this crank's counterweights would create a lot of drag and could be reduced if it was a different, more aerodynamic shape. Furthermore, the swept diameter seems like it could be reduced if a heavier material was used, which would reduce the counterweights' speed and drag. I did find a couple of articles where tungsten counterweights were used. Depleted uranium is very heavy, but perhaps Iridium or Osmium would be more practical:

http://en.wikipedia.org/wiki/Iridium

Either one would allow a thinner, smaller diameter counterweight. Personally, I would love to see the counterweights shaped like Great White Sharks to reduce drag, but wouldn't it be better to at least round off the leading edge or knife-edge the leading edge of the counterweight to reduce drag? Anyhow, here are a couple of interesting articles I found:

1. In the book Ferrari Formula One, they show the insides of the 2000 Ferrari engine. The crankshaft is a fairly conventional billet steel piece. The only exotic bits are tungsten inserts in the counterweights. In Race Engine Tech Magazine, F1 engine directors are frequently asked about the details of internal parts. There have been suggestions that some teams are using built-up welded hollow crankshafts but no one aknowledges that usually saying the cost would be prohibitive.

2. I'm told that in the late 90's Cosworth started producing what they term a "composite crank".......no dont get all excited, not a carbon fibre crankshaft..........what they were apparently doing was rather than inserting round tungsten inserts into the steel counterweights, they were making the entire counterweight from tungsten and bolting it on to the crank.
I have seen this done in the heavy diesel crankshaft industry, like 2 metre long cranks for V18 tanks and generators)......... I once visited the Krupp-Mavilor crank machining plant in southern france and this was a common solution for long-stroke forged crankshafts, the reason being that the designers needed loads of counterweight mass which was impossible to forge, therefore they simply bolted the counterweights on using two bolts - a very simple solution.
The reason Cosworth pursued this option (I'm told) was the maximum swept radius of the crank could be reduced, therefore the crank could be mounted lower, hence a lower centre of gravity, and the car corners quicker, not to mention the possible reduced crank rotating inertia???...
I'm told the F1 chassis designers give the engine designers free blow jobs when they reduce the engine C of G by only 1mm..........hope that helps!

"Everybody's nuts." - Sigmund Freud

Formula One attracts the cleverest engineers on the planet, so I would suggest if a change looks sensible to an average engineer then there is a very good reason why they do not do it.

I think the material of the counterweights has been dealt with - the picture clearly shows a different material set in the main body, and the rules forbid certain materials for cost reasons. In the case of the shape of the crank counterweights please remember that effectively they are driving a segment of a disc of air round with them, so maybe that is best encouraged rather than deflected around a 'streamlined' shape. A better option might be to use a very light material to complete the disc, then there is no leading edge: but there is more surface drag ...

I find your last point, that of 360 degree disk a good one. Just wonder how the drag on the disk's side and OD would compare with the drag of the counterweight face and rear surface.

As was already suggested, the air is being rotated with it where a dolphin shape might not help much at all, and the compete disk may also not do too much good. It seems that falls into the category of splitting hair.

KERS e. g. will be by a large degree more powerful than the air drag on the crank and it is shunned by some firms.

You cannot compare fiddling about with the crank shape to the use of KERS.

A Kinetic Energy Recovery System has significant weight, which is a big disadvantage in itself, and in most systems that weight tends to be fixed fore and aft, and relatively high. When the KERS is taking power or supplying power it obviously tends to upset the balance of the car (currently they all work on rear wheels only). So you get a car with compromised handling, compromised grip, but a power burst now and then. Factor in potential reliability issues and it is not surprising that most of the teams currently think it is not worthwhile.

Back in my youth, when I was building VW engines, one of the better available crankshafts was machined from forged billet and had disc counterweights. It was aimed at VW engines built to outputs of 200+ hp.

Oh well, so much for my dream of seeing counterweights in the shape of a shark. I had a full circle crank in the engine I built up for my old '54 VW - got it from JC Whitney. I still think that if you put a pocket of Iridium in the counterweight you could chop part of the counterweight off and still end up with a balanced engine, only the counterweight would be smaller with less drag, no matter what the shape. You couldn't get away with this in F1, but it might help in other types of racing. Thanks for the comments, it was interesting...

http://www.youtube.com/watch?v=ugSx3RZ6Lpw&NR=1

http://www.youtube.com/watch?v=gSHToyGIxWE&feature=related

One way to reduce drag is remove air in the crank case. You can use engine vaccum or add vaccum pump. Question is if there is any gain after all the extra components.

They are equipped with a dry-sump low pressure scavange system... the air density is 1/3 of the ambient air... So they don't even bother making the counterweights more aerodynamic...

Dynamic testing, with the aid of powerful strobe lights, has shown (this from memory of at least 20 years ago) that a quantity of oil mist tends to spin with the crankshaft until it is thrown centrifugally outward, impacting the walls of the engine, the bottom of the oil pan AND the underside of the pistons. A piston on its down stroke would see some counter force acting on it by the force of this oil. Granted, a piston on the up stroke would be aided, but over all, some amount of power is lost. Dry sumping draws off the accumulation of oil in the pan and solves the problem of oil splashing into the crankshaft under acceleration, deceleration and cornering. But the oil mist still spins with the crankshaft unless it is "stripped" away with a scraper plate, which is shaped to conform closely to the "safe" area next to the crankshaft assembly. This eliminates a large amount of the spinning mist and gets it to the scavenging ports quicker, which effectively increases the amount of oil available. An important thing to remember when designing a scraper plate, or a windage tray for that matter, is to leave enough clearance to account for flexing of the short block under the dynamic stresses encountered in racing. I have seen damaged engines due to bad design. Windage trays only direct any oil that strikes it away from the enclosed crankshaft area and also prevents oil in the pan from splashing onto the crankshaft assembly. I have seen either or both being used. I feel the use of both would be the most effective.

Hi,

Osmium is not a good idea: toxicity, radioactivity, price, what else?

Iridium: too costly, too difficult to bring into wanted shape.

Platinum: ok, but cost higher than Gold.

Gold: best choice, easily recycled without much loss, easily casted and machined.

Any other elements: forget. Unless you are able to mine a white dwarf neighbour star.

Shape of barracuda: good idea, discus-like:too.

Velocity is near 100m/s or Mach 0.3, so turbulence is severe, so any sharp edge will help.

RHABE

You missed out depleted uranium as a possible dense material. Relative density around 19 (sources differ), close to gold etc. I believe there is plenty of it laying around in Iraq and Kuwait. Or cheap in a bazaar.

DU is not a very good idea,

it will burn violently if ignited,

the remains of the Iraq and other shells are now highly dispersed oxide going to cause cancer if inhaled (dust blown to everywhere),

the stuff is not as bad as natural uranium as mined because the other radioactive elements that are generated over time and decay are removed by refining and half of the U235 is removed by separating the isotopes.

Uranium mine workers are allowed to inhale 1 mg per year of natural uranium dust.

Nobody really knows the chance that this will cause cancer.

The alpha particles will kill the cells they hit, nearly all of them.

But with a very low probability one cell will be struck just at the DNA site where the apoptosis mechanism is encoded. If this mechanism is lost no longer any self-destruction can be triggered.

So any additional damage that is not causing cell death may cause unlimited replication: cancer.

Very unlikely but very many alpha particles generated by radioactive decay.

Do you know a price of DU?

RHABE

I was not very serious about DU. BUT

Racing cars already use magnesium: that burns pretty well.

If it is safe enough to store lots of DU shells inside a tank it is surely safe enough to have it deep in an engine? Is the radiation level worse than living over granite?

No idea of the price.

Hi,

radiation level is not a problem, granite is much worse if leaking Radon is accumulating inhouse.

Inhaling is the problem (both U and granite).

Alpha radiation is not far reaching in air nor through any material but is doing a lot of damage in uppermost layers of cells. And in nose or lung some is going into solution, concentrated in kidneys and doing damage there.

If concentrating the uranium and other radioactive stuff in granite you would need a special permit for transportation.

RHABE

So no safety problem with uranium in an engine then - just take care when making the parts.

Price wise, it appears to be dirt cheap. Current price is under $50 a pound while gold is several hundreds of dollars an ounce.

Aha! Finally someone who appreciates the brilliance of having counterweights in the shape of fish. Seriously though, I've done some amateur airplane designing, and the emphasis put on aerodynamics and weight, especially with racing airplanes, borders on obsessive/compulsive. Laminar flow is a major focal point, and if a crankshaft travels at 0.3 mach, surely there would be some reduction in drag by changing the shape of the counterweights, or at least smoothing them out or polishing them to reduce turbulence. I actually met a white dwarf once, but never considered mining him.

http://en.wikipedia.org/wiki/Reynolds_number

A couple of things not touched on, beside density and shape, are texture and/or coatings.

Sticking with the fish theme, it has been found recently that some fish and aquatic mammals benefit hydrodynamically not just from their shape, but from the texture of their skin, which causes microcavitation. Golf balls fly farther because of their dimples (makes them cuter too ).

And perhaps non-stick and low friction wear coatings, such as teflon, might also help, much like the slime on fish scales and eels. Engine additive companies claim they improve performance by adding such materials to the oil, maybe hard coating the counterweight (non-bearing) surfaces would make things even more slippery.