asking about gearbox

[autogyro]

Shame about all the 'gaps' in torque delivery.
Thats a few seconds a lap where the car is in effect in neutral of course.
Its an absolute that comes with any 19th century lay shaft gear train.

[Tommy Cookers]

a few seconds a lap ?
less than 1 second I suggest
and that doesn't matter anyway in a fuel-limited formula

clearly the current arrangement has far better continuity of power flow than ever before
and clearly the benefits of the current arrangement outweigh the disbenefits

the main benefits are minimal width, crucially benefitting aero DF
and some 'free' (positional) step-up effect, helping to reconcile the lowest crankshaft height with the axle height

twin-clutch or planetary arrangements are bulkier and heavier and do not give the above benefits
though allowing a nearer-ideal continuity of power flow

[autogyro]

"Tommy Cookers"]a few seconds a lap ?
less than 1 second I suggest
and that doesn't matter anyway in a fuel-limited formula

Any forced gap in energy delivery reduces efficiency.

clearly the current arrangement has far better continuity of power flow than ever before
and clearly the benefits of the current arrangement outweigh the disbenefits

Modern computer shifting of lay shaft gearbox is no faster and has less driver vehicle control than manual dog shifting.

the main benefits are minimal width, crucially benefitting aero DF
and some 'free' (positional) step-up effect, helping to reconcile the lowest crankshaft height with the axle height

Lay shaft gear sets are no different in potential layout to what they always have been.
Materials have improved but not by much.

twin-clutch or planetary arrangements are bulkier and heavier and do not give the above benefits
though allowing a nearer-ideal continuity of power flow

Indeed twin clutches are bulkier and heavier as are 'conventional' planetary gear sets.
Electrically shifted planetary sets that double as energy recovery/apply units and also eliminate the need for ANY mechanical clutch definitely are less bulky (and lighter by virtue of balanced burst loads) than lay shaft gear sets.

[NL_Fer]

Do not forget the seamless shift technology, which benefits a few ms per shift. In an f1 race this is really alot. And to be explicit, i am talking about a variation on a layshaft and dogteeth box, where a special designed dogteeth ring, reduces the time, power is interrupted.

[autogyro]

Do not forget the seamless shift technology, which benefits a few ms per shift. In an f1 race this is really alot. And to be explicit, i am talking about a variation on a layshaft and dogteeth box, where a special designed dogteeth ring, reduces the time, power is interrupted.

This and all 'trick shift' systems of which I have seen dozens of variations can achieve maximum shift speed.
However the time it takes to change between gear sets in a lay shaft box is limited absolute by the capability of the gearbox and clutch to reduce or increase the engine rpm by the difference forced by the change in ratio.
As I have said many times this adds up to 'seconds' a lap where there is NO transfer of torque from the engine to the rear wheels.
Those seconds cannot be recovered with ANY kind of lay shaft gear set.

Also a good driver from the old school can equal any trick shift system with a good manual dog shift and also retain better control over the cars pitch and yaw during deceleration.
It used to be a main driving skill before computer control and sequential gear shifts now forced by rear only energy recovery and apply.
Regulation not car control.

[gruntguru]

According to this article http://www.formula1-dictionary.net/gearbox.html F1 single barrel sequential shifters lost 10-15 ms of power delivery per shift, but "With seamless gearshift now used, shift can be done with no measurable interruption to power transmission."

[autogyro]

If the gear train is reducing engine rpm at the engine by applying load against the engine during the shift, this must result in a negative torque transfer figure.
Reducing the time that this occurs with the use of trick shift (so called seamless) gear hubs does not eliminate the 'gap'.
The question is how do they measure the torque delivery.

[Tim.Wright]

If the gear train is reducing engine rpm at the engine by applying load against the engine during the shift, this must result in a negative torque transfer figure.

It will result in a positive torque (in the sense that it will accelerate the vehicle forwards) applied to the wheels. As the clutch is closed the wheels and the engine try to change speed to meet each other. The engine slows down and the wheels speed up.

[autogyro]

If the wheels speed up they are spinning in this time frame, no delivery.
If the wheels dont spin and the engine reduces its rpm there can only be zero torque transfer.

You also said when the clutch closes, so there is a neutral gap as well.
Like I said How do they measure the torque delivery.

Answer 1, not with a dyno on the car because I tried to convince the FIA to instal hub free dynos at the meetings and they moaned about cost.
The gearbox manufacturers do not test the whole package they only simulate engine and chassis and neither do the engine manufacturers.
Who has the best quess?

[Tim.Wright]

If the wheels speed up they are spinning in this time frame, no delivery.
If the wheels dont spin and the engine reduces its rpm there can only be zero torque transfer.

You also said when the clutch closes, so there is a neutral gap as well.
Like I said How do they measure the torque delivery.

Answer 1, not with a dyno on the car because I tried to convince the FIA to instal hub free dynos at the meetings and they moaned about cost.
The gearbox manufacturers do not test the whole package they only simulate engine and chassis and neither do the engine manufacturers.
Who has the best quess?

You need not to think only about the spinning of the wheels or the motor but also their relative torques. The wheels don't spin up in the sense that they are losing traction, but they slightly increase the velocity by a few percent due to the inertial torque of the engine which it is reacting which simply takes you to a higher point on the Fx vs slip graph.

The interruption would likely be measured using the longitudinal acceleration of the car which in the end is the critical parameter which needs to be managed in the shifting phase as it directly relates to the velocity of the vehicle. The aim would be to transition to the new acceleration corresponding to the new gear with zero undershoot.

[autogyro]

When the clutch is disengaged there is no torque from the engine.
Any inertia available from the engine as the clutch engages is dissipated as heat at the clutch pates.
Engine rpm is forced to decay by the torque delivery from the rear wheels to that required to match the new engaged ratio.
There is a balance of loads at the clutch and no transfer of torque.

[Tim.Wright]

When the clutch is disengaged there is no torque from the engine.
Any inertia available from the engine as the clutch engages is dissipated as heat at the clutch pates.
Engine rpm is forced to decay by the torque delivery from the rear wheels to that required to match the new engaged ratio.
There is a balance of loads at the clutch and no transfer of torque.

The heat dissipation you refer to is the product of a transfer of torque across the moving surfaces of the clutch plates. Literally the torque multiplied by the slipping velocity. If there is no torque transfer, there would be no heat.

There is no torque transfer when the clutch is disengaged but there is absolutely a torque transfer during the engagement phase which, depending on the timing, may even give a positive acceleration of the vehicle.

If you have ever performed a flat shift on a manual gearbox you would feel this boost.

[NL_Fer]

I think seamless shiftng is like bumper cars, where the car hitting is the engine, the car being hit the chassis. When they collide, the engine is slowed down, tansferring force (torque) to the chassis increasing it's speed.

Seamless shifting must feel like being hit in the back.

[autogyro]

When the clutch is disengaged there is no torque from the engine.
Any inertia available from the engine as the clutch engages is dissipated as heat at the clutch pates.
Engine rpm is forced to decay by the torque delivery from the rear wheels to that required to match the new engaged ratio.
There is a balance of loads at the clutch and no transfer of torque.

The heat dissipation you refer to is the product of a transfer of torque across the moving surfaces of the clutch plates. Literally the torque multiplied by the slipping velocity. If there is no torque transfer, there would be no heat.

There is no torque transfer when the clutch is disengaged but there is absolutely a torque transfer during the engagement phase which, depending on the timing, may even give a positive acceleration of the vehicle.

If you have ever performed a flat shift on a manual gearbox you would feel this boost.

A power upshift with a dog box is undertaken with the power fully applied by the engine.
The load is taken by the dog rings and there is no need to use the clutch.
It can be done faster than any modern trick shift with electric operation.
You do need a driver with skills now mostly lost sadly.
If you miss a shift the engine usually grenades.
Down shifts using heel and toe techniques can also match modern down shifts and have the added benefit of being undertaken in an H pattern gear shift with a far better choice of gear changes and with skill far better car control during deceleration.
I drove these kinds of shifts for many years in a number of competition disciplines and for development work on gearboxes.

There is a torque transfer as the clutch engages after the trick shift device has done its job on the modern boxes but it is torque transfer from the rear wheels to the engine to slow the engine, then there is a torque overlap to power on acceleration. There is little variation in the vehicle acceleration trace on the telemetry because vehicle inertia continues to drive the car forwards during the very small time frame.
Like I said, it is how you measure the torque transfer.

[gruntguru]

When the clutch is disengaged there is no torque from the engine.
Any inertia available from the engine as the clutch engages is dissipated as heat at the clutch pates.
Engine rpm is forced to decay by the torque delivery from the rear wheels to that required to match the new engaged ratio.
There is a balance of loads at the clutch and no transfer of torque.

The heat dissipation you refer to is the product of a transfer of torque across the moving surfaces of the clutch plates. Literally the torque multiplied by the slipping velocity. If there is no torque transfer, there would be no heat.

There is no torque transfer when the clutch is disengaged but there is absolutely a torque transfer during the engagement phase which, depending on the timing, may even give a positive acceleration of the vehicle.

If you have ever performed a flat shift on a manual gearbox you would feel this boost.

There is a torque transfer as the clutch engages after the trick shift device has done its job on the modern boxes but it is torque transfer from the rear wheels to the engine to slow the engine, then there is a torque overlap to power on acceleration. There is little variation in the vehicle acceleration trace on the telemetry because vehicle inertia continues to drive the car forwards during the very small time frame. Like I said, it is how you measure the torque transfer.

Sure and the "torque transfer from the rear wheels to slow the engine" is actually accelerating the car. It makes more sense to call this "a torque transfer from the decelerating engine releasing its "flywheel stored kinetic energy" to the rear wheels to accelerate the car" This is not a "gap" in torque delivery because energy continues to be transferred to the wheels - at a controlled rate if a slipping clutch is employed.