Inverted engines.

[trinidefender]

Just out of curiosity. Are there any regulations stopping any of the engine builders from creating and inverted V6? I ask because in WWII the Germans made many successful inverted dry sump V12 designs. An inverted engine will probably have C of G benefits and maybe in some odd way, packaging benefits.

[piast9]

Rules require the centre of crankshaft at 90 mm above the reference plane. Even if there wasn't regulated I doubt in the centre of gravity benefit. Current regulation force the COG to be at least at 200 mm above the reference plane. For sure it is possible to go lower than that. As the engines seem to be much higher than 400 mm inverting them would raise the COG.

[trinidefender]

Rules require the centre of crankshaft at 90 mm above the reference plane. Even if there wasn't regulated I doubt in the centre of gravity benefit. Current regulation force the COG to be at least at 200 mm above the reference plane. For sure it is possible to go lower than that. As the engines seem to be much higher than 400 mm inverting them would raise the COG.

Thought that rule was a minimum of 90mm above the reference plane not that it had to be 90 mm. You haven't actually answered my question, is there anything stopping them designing that?

I can see an inverted design working well with McLarens current centre radiator design.

[AnthonyG]

You mean like a BF109 engine?

[piast9]

Thought that rule was a minimum of 90mm above the reference plane not that it had to be 90 mm.

Nope, it has to be 90 ± 0.5 mm.

[trinidefender]

You mean like a BF109 engine?

Yea the BF109 used Daimler-Benz DB 601 and DB 605. Two very popular german designs.

Would be nice if F1 designers were given some freedom now. Imagine the excitement if the FIA had only mandated the minimum crankshaft height and not max and then an engine builder had come out with an inverted design. I'm sure things like this would bring people back to the sport and make it more interesting.

[langwadt]

You mean like a BF109 engine?

Yea the BF109 used Daimler-Benz DB 601 and DB 605. Two very popular german designs.

Would be nice if F1 designers were given some freedom now. Imagine the excitement if the FIA had only mandated the minimum crankshaft height and not max and then an engine builder had come out with an inverted design. I'm sure things like this would bring people back to the sport and make it more interesting.

yeh, it's not like the engine is hidden under covers so no one but the teams really know how they look

[Lycoming]

Inverted V engines offer certain packaging advantages for aircraft, such as lower CoG height, better visibility and easier access for maintenance. As far as I can tell it was done primarily for better visibility, as CG height isn't hugely important in aircraft, though the 109 had a very short track on it's landing gear so a low CG height would help avoid rollovers during turns. I've heard the argument that a low CG gives you better roll stability, but I think for small roll angles, the small angle approximation indicates that it doesn't do much in that regard.

Some aircraft, on the other hand, did it to jack up the prop axis so they could fit a bigger prop without extending the landing gear.

Anyway, none of those advantages apply to cars.

For an aircraft, when you invert the engine, you can essentially rotate the engine 180 degrees about the crank axis (or rather, the prop axis, which is offset by a gearbox on aircraft), since that's more or less fixed in space by other design parameters. That will then drop your CoG a bit by shifting the cylinder heads down, though the bulk of the engine isn't really moving. You cannot do that in a racecar, which already has a very low crank axis, because then your cylinder heads will be in the ground. You will not gain an advantage in CoG height by inverting a V engine in a car where the engine is already mounted as low as it will go.

The other advantages obviously do not apply to a mid engine racecar.

[trinidefender]

Inverted V engines offer certain packaging advantages for aircraft, such as lower CoG height, better visibility and easier access for maintenance. As far as I can tell it was done primarily for better visibility, as CG height isn't hugely important in aircraft, though the 109 had a very short track on it's landing gear so a low CG height would help avoid rollovers during turns. I've heard the argument that a low CG gives you better roll stability, but I think for small roll angles, the small angle approximation indicates that it doesn't do much in that regard.

Some aircraft, on the other hand, did it to jack up the prop axis so they could fit a bigger prop without extending the landing gear.

Anyway, none of those advantages apply to cars.

For an aircraft, when you invert the engine, you can essentially rotate the engine 180 degrees about the crank axis (or rather, the prop axis, which is offset by a gearbox on aircraft), since that's more or less fixed in space by other design parameters. That will then drop your CoG a bit by shifting the cylinder heads down, though the bulk of the engine isn't really moving. You cannot do that in a racecar, which already has a very low crank axis, because then your cylinder heads will be in the ground. You will not gain an advantage in CoG height by inverting a V engine in a car where the engine is already mounted as low as it will go.

The other advantages obviously do not apply to a mid engine racecar.

In the german WWII inverted V engines th drive was not taken directly at the height of the crank shaft, it was geared and taken at a different place more in the 'centre' of the engine.

In F1 if the designers were allowed to raise the height of the crank then the whole engine could be run inverted which would mean a very slim upper section and may benefit the aero of the cars depending obviously on what the designers do with the new packaging. The drive is then geared to come out of the crank case at a much lower point similar to what is run today with the cylinder heads very close to the floor of the car. This undeniably would have centre of gravity benefits and maybe packaging benefits.

Next question. When they say the crank must be at 90 mm +/- 0.5 mm, do they mean the crank itself or the drive taken off of the outside of the crank case?

[piast9]

There's a paragraph in the regulations:

5.3.2 The crankshaft centre line must lie on the car centre line and 90mm (±0.5mm) above the reference plane. The power unit may only transmit torque to the gearbox by means of a single output shaft that must be co-axial with the crankshaft. The output shaft must rotate clockwise when viewed from the front of the car.

[olefud]

The WW2 DB60X and Jumo engines were inverted V-12s that, as I recall, used the cam covers as dry sump scavenge locations. An inverted F-1 engine seemingly would have rod and piston windage problems even with a low pressure crankcase.

[wuzak]

Not only would you have an issue with the raised crankshaft, but you would also have issues with the induction system. The cars take a long time to change engines now - I imagine it would be worse with inverted engines.

What OI woudl like to see is them remove the rule requiring the exhaust be taken from outside the vee. May be better for packaging with them in the vee.

[wuzak]

Also, regarding width, the engines are no wider than the tub, and they are relatively short - so inverting the engine would be of negligible aerodyamic advantage IMO.

[langwadt]

Not only would you have an issue with the raised crankshaft, but you would also have issues with the induction system. The cars take a long time to change engines now - I imagine it would be worse with inverted engines.

What OI woudl like to see is them remove the rule requiring the exhaust be taken from outside the vee. May be better for packaging with them in the vee.

yes, hot inside like the le mans audis would make much more sense than trying to make the engines work upside down

[wuzak]

Here's one Ferrari prepared earlier