Roadcar transmissions and differentials to handle 5000 hp?

[J.A.W.]

AFAIR, A-G, the B-BP was designed built as a wheel driven rather than thrust propelled car,
due to the LSR regs then pertaining, & never reached its design speed due to course ( & diff!) issues..

At 500mph, it would be still be good enough to take the (now separate) wheel driven record..

[autogyro]

IMO with the placement of the engine tail pipes the BB car cannot fail to have a high component of thrust.

Specifications (Proteus Mk.705)[edit]
Data from Flight.[10]
General characteristics
Type: Turboprop
Length: 113 in (2,870 mm)
Diameter: 39.5 in (1,003 mm)
Dry weight: 2,850 lb (1293 kg)
Components
Compressor: Single 12-stage axial, followed by a single centrifugal stage
Combustors: Reverse-flow
Turbine: Two-stage power (free turbine), two-stage driving compressor
Fuel type: Aviation kerosene
Performance
Maximum power output: 3,320 shp (2,475 kW) + 1,200 lb (5.33 kN) residual thrust giving 3,780 eshp
Overall pressure ratio: 7.2:1
Air mass flow: 44 lb/s (20 kg/s)
Fuel consumption: 273 Imp gal (1,241 L) /hour
Specific fuel consumption: 0.495 lb/h/eshp
Power-to-weight ratio: 1.32 eshp/lb

[J.A.W.]

"High component of thrust"?

Sure A-G - if by "high", you mean well under 20%..

[autogyro]

"High component of thrust"?

Sure A-G - if by "high", you mean well under 20%..

Yes JAW it is but at only 20% it might show the inefficiency of the power unit.
The RR Crecy through scavenged two stroke supercharged IC engine when projected for fit to the Spitfire had over 30% of its thrust from the exhaust alone.
Of course you could argue that the Proteus was 'strangled' to meet the regulations much like modern F1 engines.

[J.A.W.]

To this day - geared turbines are 'inefficient' as locomotive ( inc' cars) power units..

The Proteus Bluebird was, sadly yet another splendid British 'defeat snatched from the jaws of victory'..
( a technically marvellous machine, but - by hook or by crook - never did perform as well as expected)..

[autogyro]

To this day - geared turbines are 'inefficient' as locomotive ( inc' cars) power units..

The Proteus Bluebird was, sadly yet another splendid British 'defeat snatched from the jaws of victory'..
( a technically marvellous machine, but - by hook or by crook - never did perform as well as expected)..

I agree, to use a turbine to drive anything other than a ships prop, there needs to be a different method for capturing and applying the energy that does not include gearing.
It is much the same for differentials that have to handle high power.
I have designed a couple of hydraulic differentials but there is a much better way.

[Edis]

While most people think Dubai Devel Sixteen 5000 hp claim is BS
http://www.carthrottle.com/post/an-inte ... developer/
What if in the future someone actually builds a 5000 hp roadcar indeed? Such an engine CAN be done specially if using NOS/nitromethane fuel.

What transmissions (gearboxes) and differentials could handle 5000 hp while not overly large and heavy for a car?

Would choices be limited to planetary transmissions as all gear teeth are working all the time?

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?
Would this totally rule out double clutch transmissions?

Any other unusual transmission designs like CVT, hydraulic, magnetic, etc.?

Would a spur-gear differential design be more resistant at a given weight?
http://en.wikipedia.org/wiki/Differenti ... fferential

Not a 5000 hp capable gearbox, but almost. This is the reduction gearing found in the current wheel driven land speed record car, which is powered by a 4400 hp Lycoming T55 turbine engine. The car is four wheel driven, and the engine, although it produces four times the power of a Veyron engine it is actually much lighter.

[J.A.W.]

See torque/hp curve of a geared automotive gas turbine here: http://www.turbinecar.com/turbook/pg02b.htm

Not as fierce on transmissions as some machines, evidently..

(Edit: link corrected)

[Edis]

See torque/hp curve of a geared automotive gas turbine here: http://www.turbinecar.com/turbook/pg2b.htm

Not as fierce on transmissions as some machines, evidently..

Your link does not work.

However, if you look at this graph you can see that a turboshaft engine produce more torque than a piston engine when the output speeds are the same. Infact, the torque curve of a turboshaft is more similar to the torque curve of an electric motor than a piston engine.



The shape of the torque curve is why cars powered by turboshaft engines can manage on only one or a few gears.

[J.A.W.]

Turbines have had a number of advantages, but fuel efficiency isn't one of them..

~20 years ago ( see page 5 of the 2-stroke thread in 'engines' section) NASA had Garrett produce a
helicopter piston engine design study - a 2.2 Litre/1000hp 2-stroke turbo-compound diesel - which showed promise..

[PhillipM]

It doesn't really have to cope with the massive torque of a 5000bhp engine, just cope with the heat generated, which is easy enough, for a road car, you only need enough gearbox and diff to handle the grip your tyres can give...

[Tommy Cookers]

I think once you go passed 300kph you should really have wheel spin!
With this kind of power you would have to go with locked axle I believe. I doubt you can find gearboxes rated at this power too, but that is not really my domain so other people will know better. Before looking at double clutch you have to find a gearbox, that is for sure. Unless you find a way to have a twin CVT with clutches (but imagine the size of the clutch)...

Thanks for your reply.
Interesting to hear about CVTs.
Can you please elaborate?
Could CVTs handle such enormous power?
Likely they will use chains (like in the banned Williams F1) instead of rubber belts usually used in roadcar CVTs.
You mentioned twin CVTs.
What did you mean by TWIN? Does that mean two sets of cones that alternate by twin clutches?

the 'original' (DAF) car CVT had a 2 (relatively small) CVT drives, ie an individual drive CVT for each rear wheel
so providing a differential effect and eliminating the usual dedicated differential mechanism

btw
surely all car CVTs have had steel belts since c 1988 ?

since the Dubai Devel's engine presumably doesn't work from 0 rpm
we might use a CVT as part of a planetary system to give continuous ratio variation with most of the torque bypassing the CVT
as some automatics did/do ? with their fluid couplings/converters
and whatever max torque we choose it does not need to pass through a friction clutch or any other modulateable device

I'm not looking at the DD
but someone from that region was asking/telling in this forum maybe 18 months about making V16s

[autogyro]

http://www.f1technical.net/forum/viewto ... &start=405

Build your V16
It does not have to have 4000 bhp because the rest can be applied electrically through the use of my ESERU.
This gear train could give you a roadable 4000 bhp car.

[The_table]

I'm sorry to drag this thread up again but ...

[mzivtins]

That guy loves it doesn't he...
This video can be summed up as: "This engine was designed specifically for this engine"

I fail to see how any engine wouldn't have its intake manifold/solution designed specifically for that engine?

Skip the video forward and see it running on race fuel etc achieving 4000+hp which is impressive.

It is a shame that the car itself is ugly, stupid and completely classless. It looks like something build buy the same guys who make MR2's into Ferrari 355 replicas: