Imaginary Locomotives

[rodent279]

10 hours ago, Northmoor said:

Then DP2 would probably have been 50101.  Just like the 90s were originally going to be 87/2s, although they are significantly different externally.

I think apart from sharing the same bogies and traction motors, 90's are significantly different to 87's. 87's are much closer to 86's. The transformer and electronics on a 90 is very different, even from 87101. I'm not even sure the traction motors are interchangeable between 87's and 90's.

[Joseph_Pestell]

28 minutes ago, rodent279 said:

I rode on an SNCF gas turbine unit once, they also ran to Calais for a while. They had a fairly reasonable life, this was in 1983. They lasted until the early 2000's, finishing up on cross country services in the South. Don't remember much about what they sounded like, but I remember the interior and the ride being similar to an HST.

 

I quite liked the RTG, certainly a big improvement for the Paris-Boulogne hovercraft service where they took over (c1980) from X4300 units. But the interiors were much below the standard of comfort of a BR Mk3.

 

Apart from the cross-country routes, where they were easier to operate on services involving reversals, their main stamping ground was Paris St Lazare to Cherbourg. They were displaced by electrification. The units for the hovercraft service were taken from the Cherbourg pool.

Edited April 22, 2020 by Joseph_Pestell

[Suzie]

I think a lot of stuff pre-TOPS had /1, /2, /3 etc. classifications for the different variants and never a /0. TOPS numbers start at zero hence the disconnect of 33/3 being numbered in the 332xx range.

[BernardTPM]

Not pre-TOPS as the Class data panels were applied from 1968, but pre individual TOPS renumbering. The Class numbers were all part of the gradual implementation of the system. Presumably the acceptance of xx/0  class numbers must have happened before they actually began to put the full TOPS numbers on.

[rodent279]

43 minutes ago, Suzie said:

I think a lot of stuff pre-TOPS had /1, /2, /3 etc. classifications for the different variants and never a /0. TOPS numbers start at zero hence the disconnect of 33/3 being numbered in the 332xx range.

I think you're right, as originally planned, the "base" class was xx/1, sub classes starting at xx/2.

[PenrithBeacon]

The issue IIRC with gas turbines is their fuel consumption at ground level is far more than their fuel consumption at the cruising altitudes of airliners. Has anything changed? Probably not. Even using unrefined oil which is cheaper than, say, diesel it is probably uneconomic to use gas turbines for surface transport and then there is the issue of carbon footprint.

[AlfaZagato]

Turbines are far more delicate than you'd think.   BR tried using fuel oil in 18000 and 18100.   Fuel oil was found to ash heavily, though, leading to significant wear on the turbine fans.   Also, the higher fuel consumption comes from the fact that, even in the Great Plains, a locomotive is rarely, if ever running at a consistent speed.

 

Now, if they applied the Fell concept with turbines, that may have been something.    The whole idea of that rig was for constant RPM, wasn't it?

[WD0-6-0]

The madness continuesI need to reposition the dome and fill (many many) gaps. The job list is still long. Most important is probably the rear truck is currently fixed and that makes a very long wheelbase so I need to change that. It's getting there though

Thanks

Rhys

[Flying Pig]

3 hours ago, AlfaZagato said:

Now, if they applied the Fell concept with turbines, that may have been something.    The whole idea of that rig was for constant RPM, wasn't it?

 

Wasn't that how APT-E was set up?  It certainly had multiple turbines.  Some of them would still need to idle when the power unit was running at part load though.

[rodent279]

1 hour ago, Flying Pig said:

 

Wasn't that how APT-E was set up?  It certainly had multiple turbines.  Some of them would still need to idle when the power unit was running at part load though.

APT-E was a turbine-electric, much like the French RTG units.

[Flying Pig]

33 minutes ago, rodent279 said:

APT-E was a turbine-electric, much like the French RTG units.

 

True, but I was thinking of the approach of dividing the drive among multiple prime movers so they could each run in an optimal rev range and be switched in and out as required.  Did APT-E run up different numbers of turbines depending on the  power required or was the power altered on all of them at the same time?

[rodent279]

2 minutes ago, Flying Pig said:

 

True, but I was thinking of the approach of dividing the drive among multiple prime movers so they could each run in an optimal rev range and be switched in and out as required.  Did APT-E run up different numbers of turbines depending on the  power required or was the power altered on all of them at the same time?

Don't know. I've got a book on it somewhere, but not easily accessible.

[The Johnster]

15 hours ago, PenrithBeacon said:

The issue IIRC with gas turbines is their fuel consumption at ground level is far more than their fuel consumption at the cruising altitudes of airliners. Has anything changed? Probably not. Even using unrefined oil which is cheaper than, say, diesel it is probably uneconomic to use gas turbines for surface transport and then there is the issue of carbon footprint.

Sorry, I'm getting a bit confused here, there's probably something I've missed.  I'm sure you are right about the fuel consumption of gas turbines, and there is plenty of evidence to back this assertion up, but AFAIK gas turbines are not used in airliners, which either use piston engines, turbo prop or turbo fan jet engines, or 'normal' turbo jet engines.  Piston engines burn avgas, aviation fuel, but the jet types burn paraffin, which is relatively cheap although of course they burn a lot of it.  But I have never heard of a gas turbine powered aircraft.

[DavidB-AU]

3 hours ago, The Johnster said:

Sorry, I'm getting a bit confused here, there's probably something I've missed.  I'm sure you are right about the fuel consumption of gas turbines, and there is plenty of evidence to back this assertion up, but AFAIK gas turbines are not used in airliners, which either use piston engines, turbo prop or turbo fan jet engines, or 'normal' turbo jet engines.  Piston engines burn avgas, aviation fuel, but the jet types burn paraffin, which is relatively cheap although of course they burn a lot of it.  But I have never heard of a gas turbine powered aircraft.

 

A jet engine is a gas turbine. The French RTG and TGV 001 had the same Turbomeca Turmo engines as the Frelon and Puma helicopters and Bréguet 941 aircraft. The UAC TurboTrain had the same engine as aircraft such as the Beechcraft King Air 90 and de Havilland Twin Otter. The Bombardier JetTrain (although experimental) had the same PW150 engine used on the Bombardier Dash-8. They just happened to be powering generators rather than props or using exhaust gases for thrust.

 

Jet-A1 is simply a very clean burning variant of kerosene/paraffin. Physically bigger gas turbines can use heavier fuel, e.g. the Union Pacific GTELs used Bunker C heavy fuel oil.

 

You can also use different grades of fuel in the same engine depending on the application, for example the Royal Navy Type 42 destroyers have the same Rolls-Royce Olympus engines as Concorde.

 

EDIT: A very crude drawing but this explains it better. The common features of gas turbines are a gas compressor, combustor and turbine. The intake air is compressed, the combustor burns the fuel with the highly compressed air and the expanding combustion gases drive the turbine which turns the shaft. A turbojet uses just the exhaust gases for thrust. Locomotive and marine use (and some other applications like the M1 Abrams tank) are turboshaft which power a generator. A helicopter is also a turboshaft which generates mechanical power for the rotors.

 

 

Cheers

David

Edited April 23, 2020 by DavidB-AU

[BernardTPM]

Unusually APT-E used Leyland gas turbines designed for road use, though of course the history of those is linked to Rover's involvement in the development of the jet engine by Frank Whittle.

[RedGemAlchemist]

17 hours ago, WD0-6-0 said:

The madness continuesI need to reposition the dome and fill (many many) gaps. The job list is still long. Most important is probably the rear truck is currently fixed and that makes a very long wheelbase so I need to change that. It's getting there though

Thanks

Rhys

Hmm. It certainly looks the part, though I see what you mean about the wheelbase. Definitely a good start though.

[PenrithBeacon]

8 hours ago, The Johnster said:

Sorry, I'm getting a bit confused here, there's probably something I've missed.  I'm sure you are right about the fuel consumption of gas turbines, and there is plenty of evidence to back this assertion up, but AFAIK gas turbines are not used in airliners, which either use piston engines, turbo prop or turbo fan jet engines, or 'normal' turbo jet engines.  Piston engines burn avgas, aviation fuel, but the jet types burn paraffin, which is relatively cheap although of course they burn a lot of it.  But I have never heard of a gas turbine powered aircraft.

I was using elderly terminology as  I might. At the heart of every turbo prop or turbo fan engine is a gas turbine which powers the prop, rotor or fan.

Early jet airliners had 'pure' gas turbines with no fan, the first 'turbo-fan' was the RR Conway which wasn't called that, but had the name 'by-pass turbojet' but that was a long time ago.

'Piston Engine' is just aviation terminology for a reciprocating internal combustion engine, not so different except perhaps in size from the engine in most cars, excepting diesels of course.

Cheers 

[Gibbo675]

7 hours ago, The Johnster said:

Sorry, I'm getting a bit confused here, there's probably something I've missed.  I'm sure you are right about the fuel consumption of gas turbines, and there is plenty of evidence to back this assertion up, but AFAIK gas turbines are not used in airliners, which either use piston engines, turbo prop or turbo fan jet engines, or 'normal' turbo jet engines.  Piston engines burn avgas, aviation fuel, but the jet types burn paraffin, which is relatively cheap although of course they burn a lot of it.  But I have never heard of a gas turbine powered aircraft.

Hi Johnster,

 

The conundrum you face may well be etymological having looked in my Latin dictionary I have found that:

• Rota - wheel
• Rotare - to turn
• Vannus -fan
• Vanus - Idle
• Turbinis - to whirl, to rotate.
• Turbare - disturb.
• Propellere - to drive.
• Referio - to hit back.
• Referre - reciprocate.
• Pistrinum - mil.
• Embolus - piston.

Perhaps looking at the meaning of the above words and the parts used in the various configuration of such engines my give clues as to the names given to particular types of engine.

The words referio and referre meaning hit back and reciprocate I would attribute indirectly to piston engines. Piston is likely from pestle which is a hand mill. Incidentally piston in Latin is embolus Greek is έμβολο, pronounced emvolo, possibly as in enveloped with a cylinder, cylindrus - cylinder.

 

The nearest I could find to jet was jettison, in Latin eicere - jettison, although the adverb ductim means in streams. Likely as in that the gas flow is streamed in the way that petrol is jetted into a carburettor.

 

Here is another, locomotive comes from the Latin:

• Locare - to place.
• Locus - site, locality.
• Motare - to move. 

Also to have a cause is to have a motive.

 

Should you be wondering. I've nothing else to do right now but read my dictionaries !

 

Gibbo.

[Clive Mortimore]

7 minutes ago, Gibbo675 said:

Hi Johnster,

 

The conundrum you face may well be etymological having looked in my Latin dictionary I have found that:

• Rota - wheel
• Rotare - to turn
• Vannus -fan
• Vanus - Idle
• Turbinis - to whirl, to rotate.
• Turbare - disturb.
• Propellere - to drive.
• Referio - to hit back.
• Referre - reciprocate.
• Pistrinum - mil.
• Embolus - piston.

Perhaps looking at the meaning of the above words and the parts used in the various configuration of such engines my give clues as to the names given to particular types of engine.

The words referio and referre meaning hit back and reciprocate I would attribute indirectly to piston engines. Piston is likely from pestle which is a hand mill. Incidentally piston in Latin is embolus Greek is έμβολο, pronounced emvolo, possibly as in enveloped with a cylinder, cylindrus - cylinder.

 

The nearest I could find to jet was jettison, in Latin eicere - jettison, although the adverb ductim means in streams. Likely as in that the gas flow is streamed in the way that petrol is jetted into a carburettor.

 

Here is another, locomotive comes from the Latin:

• Locare - to place.
• Locus - site, locality.
• Motare - to move. 

Also to have a cause is to have a motive.

 

Should you be wondering. I've nothing else to do right now but read my dictionaries !

 

Gibbo.

Go and make some DMUs.

[Gibbo675]

2 minutes ago, Clive Mortimore said:

Go and make some DMUs.

My Dear Clive,

 

I have already made them they only require painting, WE  sort of know about that sort of thing don't WE.

 

Oh alright then, this afternoon !

 

Gibbo.

[rodent279]

14 minutes ago, Gibbo675 said:

Hi Johnster,

 

The conundrum you face may well be etymological having looked in my Latin dictionary I have found that:

• Rota - wheel
• Rotare - to turn
• Vannus -fan
• Vanus - Idle
• Turbinis - to whirl, to rotate.
• Turbare - disturb.
• Propellere - to drive.
• Referio - to hit back.
• Referre - reciprocate.
• Pistrinum - mil.
• Embolus - piston.

Perhaps looking at the meaning of the above words and the parts used in the various configuration of such engines my give clues as to the names given to particular types of engine.

The words referio and referre meaning hit back and reciprocate I would attribute indirectly to piston engines. Piston is likely from pestle which is a hand mill. Incidentally piston in Latin is embolus Greek is έμβολο, pronounced emvolo, possibly as in enveloped with a cylinder, cylindrus - cylinder.

 

The nearest I could find to jet was jettison, in Latin eicere - jettison, although the adverb ductim means in streams. Likely as in that the gas flow is streamed in the way that petrol is jetted into a carburettor.

 

Here is another, locomotive comes from the Latin:

• Locare - to place.
• Locus - site, locality.
• Motare - to move. 

Also to have a cause is to have a motive.

 

Should you be wondering. I've nothing else to do right now but read my dictionaries !

 

Gibbo.

One of the hidden benefits of COVID-19. We might all end up speaking better Latin!

[The Johnster]

Nil Illigitami Carborundum...

[RLBH]

On 21/04/2020 at 23:47, Northmoor said:

Yes, that's how gas turbines work; they are most efficient at or near maximum power.  Which is why they are generally unsuited to rail applications but highly suited to aircraft.

This is because a gas turbine engine needs to run the compressor stage, which uses something like 70% of the power developed in the turbine stage at full power. As a consequence, even at idle the engine is running at about a 70% throttle setting yet produces no net power - it's all used up running itself.

[Budgie]

On 23/04/2020 at 11:08, Gibbo675 said:

The nearest I could find to jet was jettison, in Latin eicere - jettison, although the adverb ductim means in streams. Likely as in that the gas flow is streamed in the way that petrol is jetted into a carburettor.

 

 

It comes from iacere, meaning to throw, through its frequentative iactare, which became the French jeter, also meaning to throw..

[rockershovel]

Brutus adsum iam forte

Caesar aderat

Brutus sic in omnibus

Caesar sic in at