Gear-shifting gearboxes that can handle 5000 hp?

[DasKleineWunder]

Are there industrial gear-shifting gearboxes that can handle 5000 horsepower?
If so which ones? Can you please name a few and post some links if possible?

I asked because there are rumors of a 5000 hp supercar: The Devel Sixteen.
While most people think they are lying/pipedreaming about the 5000 hp, this got me thinking on technical details to handle such enormous power.

Would choices be limited to planetary transmissions?

Could synchronous transmissions be used within a reasonable size and weight?
How large would gears need to be since only a few teeth contact each other at a given time?

 

[romke]

i doubt whether there are any - and if so they will certainly not be designed in a way that will fit a automotive application...

automotive gearing usually is designed for short term use - where the life expectancy of the various parts together adds up to the mileage that may be expected, say 300000 km. that means that if you have a 6 speed transmission the 6th gear usually will last a lot longer then first gear because its anticipated use will be much longer within the 300000 m timeframe. the reverse gear may not live longer then just half a hour under full load - which is much longer then the use it will see over the anticipated 300000 km life.

industrial gearing usually is designed more or less for "eternity", say 30+ years or so under the anticipated load conditions (torque,speed, shock loading etc). that means that compared to automotive transmission with the same power/torque rating it will be much heavier, larger and with far lower loads on gears and bearings.

heavy duty automotive gearboxes (trucks, earth moving equipment) will be somewhere in between those extremes, say 1.500.000 km or a equivalent value in hours, but still based more or less on the "automotive" design principle: not every individual gear has to last that long, all gears together should last long enough to attain the design life and be capable of withstanding the loads they individually will have to take within that design life under the anticipated conditions of use.

 

[tbuelna]

There are industrial transmissions with variable speed capability that can handle 5000hp or more. But they would likely be far too heavy and bulky for any road vehicle.

I think it would be possible to design a multi-speed gear transmission for a 5000hp wheel-driven vehicle. The specific design of the gearsets would depend on the torque/speed/ratio characteristics required. I can't say if it would meet your definition of "a reasonable size and weight".

I actually have a bit of experience designing a somewhat similar type of transmission. I worked on some detailed design studies for a range of two-speed aircraft transmissions for 2500hp to 11,000hp. Weight and efficiency were important factors with these designs.

 

[drawoh]

DasKleineWunder,

Is this 5000hp car going to be marketed as an economy car?

If you are not limited by silly things like budgets, there should be no problem designing and building a transmission that can transmit 5000hp. The results will not compete for price with my Honda Fit.

--
JHG

 

[geesamand]

It can certainly be done. An industrial drive will not be suitable for comparison.

There are numerous racing transmission designs that may work or be the best platform for up-scaling to the needs. Racing transmissions are typically not planetary.

You will end up with a really big (for automotive) transmission in any case. The thing about 5000hp (or any big HP number) is getting it turned into torque - without racing tires and aerodynamic downforce, street cars are always limited in the capacity to use torque. So the torque transmission requirements won't simply be 5x that of the Veyron.

 

[tbuelna]

The image below is a single planetary gear reduction stage that drives the 32,000hp fan on the PW8000 engine. This is about as compact and lightweight as planetary gear stages can be made. It has a 3:1 reduction ratio and the input torque is around 19,000 ft-lb.

 

[MikeHalloran]

I've seen pulling tractors powered by five Rodek engines that are probably rated at more than 5000HP in aggregate. They have transmissions of some kind. I'm not sure if they're shifted on the fly; they seem to just ease out the clutch to bring the tires up to ~90 mph, and let the dirt act as a sort of fluid coupling while the tractor drags the sled.

Even one Rodek and a suitable transmission would probably not fit in the Devel Sixteen, so there may be some hyperbole involved, but just as in pulling, the weak link is probably the tire/road interface, so the power rating of the transmission is pretty much irrelevant.





Mike Halloran
Pembroke Pines, FL, USA