Weird idea about using only 6 gears

[hollus]

Hypothetical question: Could there be a benefit to running with only 6 of the 8 available gears?

I'll confess to thinking about this while wondering why it was so difficult to find data for the Mercedes team running in 8th or in 1st. I've since found a video of Rosberg using 1st gear out of a pit stop, so I guess there will also be an 8th coming into service, probably already in China.

But as teams get to know their power units better and with the very wide powerband of 2014, it is conceivable to prepare 6 gear ratios spaced so that one can run the whole season with just those 6 and running between, say, 10000 and 13000rpm. In that case one could have 2 "fake" gear ratios in the powertrain that are only there to meet the conditions of the rule book.

This is what the rules say about gears, AFAIK a sequential shift from gear to gear is specified but I don't thing it says that you need to actually engage any particular gear at any time:

9.6.1 The number of forward gear ratios must be 8.

9.6.3 No forward gear ratio pair may be :
a) Less than 12mm wide when measured across the gear tooth at the root diameter or any point 1mm above or below the root diameter. Above this area each side of the gear teeth may be chamfered by a maximum of 10¢ª. In addition, a chamfer or radius not exceeding 2.0mm may be applied to the sides and the tip of the teeth.
b) Less than 85mm between centres.
c) Less than 600g in weight (excluding any integral shaft or collar). If an integral shaft or collar is to be excluded the mass of this may be shown by calculation assuming the gear to be 12mm wide and the shaft geometry to be the same as that where slide on gears are used.

9.6.4 Gear ratios must be made from steel.

9.8.2 Gear changing is restricted during the following periods :
One gear change is permitted after the race has started and before the car speed has reached 80km/h, provided every gear fitted to the car is capable of achieving at least 80km/h at 15,000rpm.

One could desing 2 fake gears, say 1st and 8th, but why not 7th and 8th, which are as small as possible while meeting the weight and dimension rules, freeing up space for other mechanisms to go in. The gears colud be of a very small diameter, wide if necessary to reach 600g, and have a "real plate ratio" of 1:1. Imagine a pair of fat "fake wheels" with only 6 teeth. The mechanisms do not neet bo be able to reach these gear plates or bringing into close contact at all, ever. The gear are there, the driver just never selects them!

The benefits could be a smaller gearbox and consequently better packaging and aero, possibly less friction and less rotatioal inertia in the gearbox, which translates into a slight gain in power to the wheel in all six real gears.

The drawbacks are obvious, but would there be any point to doing this at all? It is conceivable to gain a measureable advantage by doing this?

[machin]

If you had a perfectly flat power curve from 0 RPM up to the rev limit then there is literally no advantage of having more than one gear....

Now the new engines have a fairly flat power curve from about 50% revs upwards, so they probably could get away with 6 gears this year...

I guess one advantage of more gears is that the average wear on the gears is less (since you'll be using each one 1/8th of the time rather than 1/6th of the time).....

The other thing is that if your fake gears meet the minimum size and weight requirements, you may as well make them real gears...?

[hollus]

But one thing is translational inertia, that one you suffer anyways, and another is rotational inertia, which almost goes away with a small enough radius. And the dimensional constrains specify little more than distance between centers...

[machin]

Presumably the FIA will insist that the gears on the Primary and secondary shafts which make up each of the two "fake" ratio gear pairs are actually in mesh, so if you make the gear on the primary shaft small then the corresponding gear on the secondary shaft must be very large, i.e Radius of gear1+Radius of gear 2 must equal the distance between the primary and secondary shafts otherwise it wouldn't count as a ratio and would fail the FIA's requirement for 8 ratio gear pairs.... ????

[tommylommykins]

If you had a perfectly flat power curve from 0 RPM up to the rev limit then there is literally no advantage of having more than one gear....

I don't think this is true. My Ford Fiesta gives much more acceleration at 3500RPM in first gear than at 3500RPM in fifth gear. Gears are stull useful for their torque multiplication effect.

[Tommy Cookers]

if your Fiesta had a truly flat power curve down to 0 rpm it would have torque approaching infinity towards 0 rpm
so there would be no advantage in having more than the correct 1 gear
the 2014 car is rather more like the above conceptual ideal than is the 2013 car

@ Hollus etc
people have said loosely speaking the regs intent was to use gears 1-6 at Monaco and 3-8 at Monza (ignoring starts, pits etc)
any view on this idea ?

[machin]

My Ford Fiesta gives much more acceleration at 3500RPM in first gear than at 3500RPM in fifth gear. Gears are stull useful for their torque multiplication effect.

The power output from your Fiesta is a long long way off the ideal flat power curve that I talk about as you can see from the left hand graph below, and that is why you benefit from a multiple ratio gearbox.

[autogyro]

With the flatter torque curves this year it would be possible to use only six gears for acceleration and even get away with five on some circuits.
However the reasons that the FIA mandated eight gears was not because of the effect on acceleration.
They were well aware that controlling the much larger KER from the power unit would be very difficult when trying to balance it with the rear wheel brakes.
With six gears or even seven, during hard deceleration the sudden jerks caused by the crude quick shift mechanisms in the single lay shaft gearbox would upset the rear of the car causing uncontrolled spins.
This has proven to be the case to a degree even with eight gears available.
There is a similar but more driver controllable problem managing the application of power during corner exit when the car is unbalanced due to the two power sources.
The difference between driver control over the throttle and the drivers far less control over a foot brake working over a short throw coupled to a KER program and fly by wire rear brake balance program is obvious to see.
The main time and cost working the cars up for 2014 has been spent on getting them to work with the mind blowingly pathetic regulations that prevent any technical innovation and also destroy any of the old driver control skills in gear shifting to control the power units. (the origin of this goes back to semi auto sequential gearboxes and the FIA's inability to regulate for the future to maintain driver skill).
Another reason for mandating eight gears in a 19th century gearbox design is to prevent any and all innovation in the technology of transferring engine power to the drive wheels.
With other transmission technology outlawed by the narrow concept regulations ICE development and F1 will remain stuck in previous decades.

[machin]

I've corrected your post Auto:

With the flatter POWER curves this year it would be possible to use only six gears

For a self confessed gearbox "expert" it still surprises me how you continue to misuse power and torque terms.

Interestingly the people who actually use the current Zero-shift gearboxes actually report that they shift smoother than the old generation due to the fact there is a smaller disturbance in transmitted power....

[autogyro]

I've corrected your post Auto:

With the flatter POWER curves this year it would be possible to use only six gears

For a self confessed gearbox "expert" it still surprises me how you continue to misuse power and torque terms.

Interestingly the people who actually use the current Zero-shift gearboxes actually report that they shift smoother than the old generation due to the fact there is a smaller disturbance in transmitted power....

What zero shift report or those who use their gearboxes is hardly unbiased opinion.
Zero shift boxes will be smoother with eight gears.
Being smoother during the shift does not negate the jerk caused by the rpm drop between shifts or the lack of driver control, eight gears simply reduces the problem.
Torque? Power? at least I spell it correctly. hahaha

[Jersey Tom]

To me it seems silly to carry 2 gears in your trans that you refuse to use. If you need to have them, why not get the most out of them?

Basically you'd be giving up something concrete, for a speculative marginal (or trivially small) gain. Not a good recipe for success

It's a dangerous thing... easy to get into the mindset of trying to scrap up tiny gains, but in doing so, fall into the trap of giving up something bigger while doing so for a net loss.

[Pumaracing]

I've run simulations of the 2014 engine performance down to only 5 gears and it barely makes any difference to acceleration with such a flat power curve. You have to rev the engines higher of course to obtain the best gear change point. I'm bemused by these gearbox rules in conjunction with the engine ones. 7 speeds are ample. 6 would be ok. 8 is just ridiculous complexity and extra expense which makes a nonsense of the FIA talking about limiting development costs all the time by restricting track testing and other things when actually all they do is keep introducing things which cost a fortune to develop.

[Mystery Steve]

've run simulations of the 2014 engine performance down to only 5 gears and it barely makes any difference to acceleration with such a flat power curve.

Would you mind sharing those results, and a description of the simulation used to obtain them?

[autogyro]

With five gears the cars would be un-drivable under braking.
It is that simple.

[Tommy Cookers]

the mgu-k benefits from being used at relatively constant (high) rpm ie from using plenty of gears

this is critical to maximise harvesting (for any torque greater rpm = greater voltage = greater power)

and it is more efficient in the mgu-k and its drive electronics, this means less waste heat ie less cooling need
eg 98% efficiency means half the cooling need of 96% efficiency (to use someone else's explanation)
and any DC:mgu-k efficiency over 95% is legitimate profit eg 122 kW would be legal this way

motoring or generating, it's always better to use all the available voltage than to increase current attempting to compensate


anyway, surely they will at each track use the 6 or 7 gears that are best matched to that track ?
or is there now evidence eg for the same 6 to be used at all tracks ??