Turbine engines

It may be of interest that one can have a turbine engine without any electrical power. The Sud-Ouest Djinn helicopter was started with a dirty great handle sticking out the side of the engine. Granted it did have a magneto to ignite the fuel but in cold weather that didn't work so we threw a burning newspaper down the intake. So you could always have a flame tube.

Lots of bigger turbines are started with cartridge or 'Avpin' (Isopropelnitrate) starters.

A lot of turbines run on steam! The big problem with turbine engines is engineering and materials.

As a general rule turbines of all stripes (jet, steam, electrical generation) run best at high temperatures, revolutions and pressures. Most of the things connected to them (air and sea propellers, hydro water flows etc) work best at low temps and low pressures.

This requires a lot of complicated gearing that requires VERY precise engineering and components made with exotic alloys often involving elements such as Tungsten, Aluminium and Titanium nearly all of which are currently outside of Safeholds no electricity tech base.

By 'electrical generation' I guess you mean hydro-electric plants? The generators can be direct-drive from the turbine shaft in those.

My understanding is that the optimum speed of a turbine is inversely proportional to the density of the working fluid. Blading is then dependent on speed, pressure and density. All of which mean that water turbines are well within the reach of current Charisian tech - the oldest RW example I've seen is from the 1850s, and it wasn't the earliest by any means. IIRC, Howsmyn is already using them to replace water-wheels.

That doesn't mean that gas or steam turbines are within easy reach, for the reasons you give, although ISTR Howsmyn thinking about them for driving his air compressors. [again, an application that avoids gearing]

Silverwall wrote:A lot of turbines run on steam! The big problem with turbine engines is engineering and materials.

As a general rule turbines of all stripes (jet, steam, electrical generation) run best at high temperatures, revolutions and pressures. Most of the things connected to them (air and sea propellers, hydro water flows etc) work best at low temps and low pressures.

This requires a lot of complicated gearing that requires VERY precise engineering and components made with exotic alloys often involving elements such as Tungsten, Aluminium and Titanium nearly all of which are currently outside of Safeholds no electricity tech base.

Louis R wrote:By 'electrical generation' I guess you mean hydro-electric plants? The generators can be direct-drive from the turbine shaft in those.

My understanding is that the optimum speed of a turbine is inversely proportional to the density of the working fluid. Blading is then dependent on speed, pressure and density. All of which mean that water turbines are well within the reach of current Charisian tech - the oldest RW example I've seen is from the 1850s, and it wasn't the earliest by any means. IIRC, Howsmyn is already using them to replace water-wheels.

That doesn't mean that gas or steam turbines are within easy reach, for the reasons you give, although ISTR Howsmyn thinking about them for driving his air compressors. [again, an application that avoids gearing]

Silverwall wrote:A lot of turbines run on steam! The big problem with turbine engines is engineering and materials.

As a general rule turbines of all stripes (jet, steam, electrical generation) run best at high temperatures, revolutions and pressures. Most of the things connected to them (air and sea propellers, hydro water flows etc) work best at low temps and low pressures.

This requires a lot of complicated gearing that requires VERY precise engineering and components made with exotic alloys often involving elements such as Tungsten, Aluminium and Titanium nearly all of which are currently outside of Safeholds no electricity tech base.

Low tech Turbines are possible for mechanical power - at an old lumber/grist mill run by our local metroparks, they have a 1850s era turbine system where water accumulates in an accumulator tank, then falls through an open sluice into the turbine, then down to the river. Over the years, they even had the turbine powering an electrical generator for the nearby town (after hours when the mill was not in operation.) Unfortunately, I've never actually seen the turbine itself - the metroparks folks keep muttering about OSHA everytime I mention getting going under the floor to take a look at it.

It's a Tylor turbine, made in 1907, but patented in the 1850s - definitely within Safehold technology - for the creation of mechanical energy.

Ahhh.

A subject that is near and dear to my heart - gas turbine engines.

First things first - steady-state operations - the only things you need are air and fuel. Once it's running, it's self sustaining.

Startup - You need an initial source of power to get rotational speed up high enough that the compressor section is actually compressing air. On older aircraft, that was provided by an external compressed air source. Now you need to inject fuel into the compressed air steam in the burner section. Preferably well-atomized fuel, but if you're willing to accept less-than-optimum burn, it can be larger "droplets" of fuel. Finally you need a source of ignition. On aircraft it is an electrical ignitor, but there's no reason whatsoever (as the earlier poster stated) that you couldn't have a "flame tube" extending from outside the engine into the burner section. Once one section is ignited, the flame will propagate the way it does with a modern gas grill that has multiple burners.

So now you've got a turbine engine that is turning and will continue to do so as long as it has fuel and air. You've got to USE that power somehow.

Between the compressor section and the burner section you put in a conventional 90-degree gear system that redirects power from the shaft perpendicularly from the axis of the engine to the outside of the engine. You can then route this rotational power through another gear system to "downshift" the speed to whatever speed you want. This way you take advantage of the high speed of the motor itself and enable for lower speeds for whatever bolt-ons you want to attach - a low-temperature compressor, a generator (yes, I know it's proscribed, I'm only throwing it in for example), hydraulic pumps, fuel pumps, or anything else you might want.

There's also the idea of a "constant-speed drive" that will allow a constant output speed for varying input speeds. In aircraft, you need a constant generator speed / rotation but have varying input speeds (engine RPM)based on different flight situations. The CSD is what takes care of this - it's a mechanical gear system, I think sun/planet. By the way - by allowing the CSD to receive power from either end, you can also use this as your "starter motor," turning it into a "constant speed drive / starter." This is what we had on the A6 Intruders I flew - a CSD/S.

Easy-peasy, lemon squeezy... Pretty cool stuff, pretty simple, really, just a bit challenging to actually BUILD it and make it work because some of the tolerances and materials could be difficult. But conceptually simple.

WeberFan wrote:<snip>

Easy-peasy, lemon squeezy... Pretty cool stuff, pretty simple, really, just a bit challenging to actually BUILD it and make it work because some of the tolerances and materials could be difficult. But conceptually simple.

unfortunately, the materials and tolerances are the rub.

Most importantly, your turbine used precision ball bearings. I don't know if Safehold is up to metal roller bearings or Babbitt metals yet, let alone ball bearings, and we need those techs before we can get a good efficient power plant.

Louis R wrote:By 'electrical generation' I guess you mean hydro-electric plants? The generators can be direct-drive from the turbine shaft in those.

My understanding is that the optimum speed of a turbine is inversely proportional to the density of the working fluid. Blading is then dependent on speed, pressure and density. All of which mean that water turbines are well within the reach of current Charisian tech - the oldest RW example I've seen is from the 1850s, and it wasn't the earliest by any means. IIRC, Howsmyn is already using them to replace water-wheels.

That doesn't mean that gas or steam turbines are within easy reach, for the reasons you give, although ISTR Howsmyn thinking about them for driving his air compressors. [again, an application that avoids gearing]

Silverwall wrote:A lot of turbines run on steam! The big problem with turbine engines is engineering and materials.

As a general rule turbines of all stripes (jet, steam, electrical generation) run best at high temperatures, revolutions and pressures. Most of the things connected to them (air and sea propellers, hydro water flows etc) work best at low temps and low pressures.

This requires a lot of complicated gearing that requires VERY precise engineering and components made with exotic alloys often involving elements such as Tungsten, Aluminium and Titanium nearly all of which are currently outside of Safeholds no electricity tech base.

Although I don't have the books in front of me, it is my recollection, that Howseman already has water-powered turbines running at Delthak.

yep water turbines are in play already.

What many of us question is the ability to make use of the other turbines that exist in the real world.

The two biggest of these are naval steam turbines and obviously gas turbines of the jet or M1 abrahms variety.

These are the ones that require levels of manufacturing precision and gearing that are (as far as shown by the text) probably beyond the safehold tech base.

It's not the concept that is difficult it is the technical execution with high temp and strength compressor blades. You can use stainless stell with naval steam but you need exotic alloys for the Gas turbines, Just look at the jumo engines on the ME 262. They used stainless basically and as a result had to be rebuilt from the ground up every 10 hours of opperation because they burned themselves up.

Also at the speeds that naval and jet turbines spin you need very very good bearings and micrometric manufacturing precision and advanced reduction gears to translate the high rotational speed into somthing useful in a naval or propdrive setting. This actually delayed the use of turbines in a naval setting for quite a while and led to some very fuel inneficient ships.

There is no evidence of ball bearing technology being present on safehold at this stage though some basic form of it may be implied by the bycicles being built by Howmsman but I suspect a more primative bearing is more likely.

Theemile wrote:

WeberFan wrote:<snip>

Easy-peasy, lemon squeezy... Pretty cool stuff, pretty simple, really, just a bit challenging to actually BUILD it and make it work because some of the tolerances and materials could be difficult. But conceptually simple.

unfortunately, the materials and tolerances are the rub.

Most importantly, your turbine used precision ball bearings. I don't know if Safehold is up to metal roller bearings or Babbitt metals yet, let alone ball bearings, and we need those techs before we can get a good efficient power plant.

I think you will find that ball bearings are not the only choice. A sleeve type hydrostatic bearing has a lower wear and friction (but needs a constant high pressure oil supply both before start and after shutdown to avoid damage). A magnetic bearing would be another option (using permanent magnets would be possible although the initial magnetization could be interesting). Gears are only needed if you don't like noise as a pure jet would be a possible propulsion source for jet aircraft, hovercraft (lofted by a eductor effect fan system (read Dyson blower)), ekranoplanes or hydrofoils. Low bypass (20:1) would be possible with extra turbine stages (747-100 series technology engines). Magnetic, pneumatic (using a compressed air bleed) or hydraulic couplings could also be used to drive accessories like oil and fuel pumps.
Marine propellers and land vehicles should for the moment be run with reciprocating steam engines as these are mechanically simpler.

The biggest sticking point with turbine engines is reduction gears. A turbine engine is optimal at high speed like 5-10k RPM conversely marine engines work best at slower speeds like 250-300 RPM. The destroyer I served on used LM 2500 engine, the same engine used on the DC-10. But the shafts only turned IIRC at a maximum of 350 RPM. I remember watching the replacement of a reduction gear at Long Beach NSY. The gear they pulled was the size of a small car and weighed 15-20 tons and took almost three months to manufacture a replacement. Reduction gears are known in naval construction as a long lead item meaning that they are ordered oftentimes years in advance of installation. I wouldn't be surprised if the current federal budget has a line item authorizing funding for the reduction gears for the carrier Enterprise which is scheduled for commissioning in 2025.

FYI the U.S. used triple expansion engines on some Liberty and Victory ships to speed up construction of the ships because of the bottle neck in manufacturing reduction gear.