Request for assistance - a world without electricity

[catsmate]

I'm not sure if this is the correct area to post this, but it's science related so I'll start here.

I'm looking for some advice and suggestions for a gaming (tabletop RPG) scenario I'm working on. Especially from those of a scientific or devious bent.

Basically the setting for the scenario is a planet without electricity and similar technology, based on Exxilon from the classic Doctor Who serial 'Death to the Daleks'.
In that story the TARDIS lands on the mysterious planet Exxilon and suffers a total power failure, nothing using electricity (or similar tech) works. Oil lamps and machine guns do work, TARDISes, spaceships, blasters and electric torches don't.
The problem is caused by some remanent machines from an advanced (clarketech level) alien race.

My victims players will know about this in advance and will hopefully prepare well.

Unlike, say, Stirling's Emberverse, other moderately advanced technology works fine; steam engines, explosives (including firearms), compressed gases et cetera. I'm also declaring, by GM fiat, that nuclear energy also works OK, so a steam engine powered by radioactive decay (or a direct heat/light source so powered) will function but it couldn't generate electric power.

What I'm looking for is ideas on interesting/usable tech for this environment.


Stuff that won't work.
1. Energy weapons: no gauss rifles, pulsers, lasers, plasma guns, blasters, charged particle spitters, implosion bombs, plasma or warp grenades. This also rules out thing like proximity fused grenades or rockets.
2. Radio: also similar ultra-tech comms using subspace, neutrinos or gravity ripples
3. Computers: including robots
4. Most advanced sensors: no RADAR, image intensifiers, multi-scanners, tricorders and similar
5. Most advanced transport: no on planet teleportation, anti-gravity vehicles
6. Other stuff: no recon drones, nanotech, advanced medicine

Specific points.
1. Getting from orbit to the surface
Some sort of simple re-entry vehicle without advanced (electronic or computer controlled) guidance or sensors (no RADAR altimeters). Also limited to chemical rockets (no anti-gravity). Controls would have to be mechanical, pneumatic or hydraulic.
Or maybe they can teleport/transport/transmat down but are then stuck.

2. Communications from surface to orbit
Optical or thermal? And likewise for the return leg.

3. On-planet communications
Any ideas? No radio so I assume they'll be limited to optical signal (light, flags, heliographs) and shouting.

4. On-planet transport
As far as I can see simple vehicles not using electrical systems should be OK. No spark ignition. Microlights for aerial recon.

5. Weapons.
Chemical firearms, explosives, various gases. No advanced sighting devices however.

6. General survival.
Bring your own food, water purification gear, oil lamps (or chemi-luminescents or radioactive decay glowpups), gather firewood (or bring nuclear heaters). No self-erecting tents or holobases.
Given the hostility of the (primitive) locals maybe some fortifications, concertina wire.

7. Getting back to orbit.
Well the plan is that our heroes will destroy the alien machinery and re-enable advanced technology. But I'm sure they'll want a backup plan. Just in case...
So, how do you get a group of about six people from the surface of a (roughly) Earthlike planet to low orbit (at least 250km) without using electrical or electronic systems? No electric fuel pumps, no RADAR, no computers, no radio..........
Also the craft needs to work without much infrastructure, so no multi-kilometre concrete runways.

Nuclear weapons.
This intrigues me. I don't see an implosion weapon, even one fabricated using very advanced tech, working without electrics. Unless some sort of pneumatic systems is possible for the explosive lens detonators. However a gun-barrel weapon should be workable; mechanical timer, percussion detonator et cetera.
Better be careful with it.
Likewise can anyone come up with a plausible method to store anti-matter without electricity or magnetic fields?


So, any advice, suggestions, comments?

 

[geni]

Stuff that won't work.
1. Energy weapons: no gauss rifles, pulsers, lasers, plasma guns, blasters, charged particle spitters, implosion bombs, plasma or warp grenades. This also rules out thing like proximity fused grenades or rockets.


So, any advice, suggestions, comments?

Chemical oxygen iodine lasers exist as do various other lasers driven by chemical reactions.

 

[catsmate]

Chemical oxygen iodine lasers exist as do various other lasers driven by chemical reactions.

Indeed, but how useful would they be, as a weapon, communication device or other tool?
Actually on investigation a chemical laser could be a useful communications method to orbit, using some sort of mechanical shutter system. Assuming the planets atmosphere doesn't absorb at the emitted wavelength.

Thank you for that.

 

[Toke]

Water will, weather permitting, provide a not too bumpy runway.
I am not sure how the calculations work out for a winged reentry vehicle carrying enough fuel to get back in orbit, guess it is possible with advanced enough manufacturing capability.


You could allow the teleporter to work as the mechanism is on a ship in orbit.

As for firearms, you could do without gunpowder. http://en.wikipedia.org/wiki/Girandoni_Air_Rifle

It looks like your characters will need a serious budget for some of the more specialized non-electric equipment, who is funding them?

 

[catsmate]

Water will, weather permitting, provide a not too bumpy runway.

Bugger, I hadn't thought of that. I've been thinking too much of Exxilon which was a barren, rocket desert. (It was Who so it was filmed in a quarry.)
Good idea. A nearby lake gives them many options for getting into trouble.

I am not sure how the calculations work out for a winged reentry vehicle carrying enough fuel to get back in orbit, guess it is possible with advanced enough manufacturing capability.

I suspect some handwavium will be needed. I'm crunching the numbers on a nuclear thermal rocket, using water as the reaction mass so I *think* they can get back to orbit. However without communications, RADAR or electrical systems it'll be interesting.

You could allow the teleporter to work as the mechanism is on a ship in orbit.

I'm reluctant to give them an easy way out. Way in, yes; let them get into trouble.

As for firearms, you could do without gunpowder. http://en.wikipedia.org/wiki/Girandoni_Air_Rifle

I was thinking conventional firearms for lethal weapons, possibly paintball guns firing chemicals for a less lethal option.

It looks like your characters will need a serious budget for some of the more specialized non-electric equipment, who is funding them?

Well effectively a Time Lord.
They've access to Trek level tech so making stuff isn't the problem (replicator/nanofabricator) it's the concepts.

 

[Aepervius]

I'm not sure if this is the correct area to post this, but it's science related so I'll start here.

I'm looking for some advice and suggestions for a gaming (tabletop RPG) scenario I'm working on. Especially from those of a scientific or devious bent.

Basically the setting for the scenario is a planet without electricity and similar technology, based on Exxilon from the classic Doctor Who serial 'Death to the Daleks'.
In that story the TARDIS lands on the mysterious planet Exxilon and suffers a total power failure, nothing using electricity (or similar tech) works. Oil lamps and machine guns do work, TARDISes, spaceships, blasters and electric torches don't.
The problem is caused by some remanent machines from an advanced (clarketech level) alien race.

My victims players will know about this in advance and will hopefully prepare well.

Unlike, say, Stirling's Emberverse, other moderately advanced technology works fine; steam engines, explosives (including firearms), compressed gases et cetera. I'm also declaring, by GM fiat, that nuclear energy also works OK, so a steam engine powered by radioactive decay (or a direct heat/light source so powered) will function but it couldn't generate electric power.

What I'm looking for is ideas on interesting/usable tech for this environment.


Stuff that won't work.
1. Energy weapons: no gauss rifles, pulsers, lasers, plasma guns, blasters, charged particle spitters, implosion bombs, plasma or warp grenades. This also rules out thing like proximity fused grenades or rockets.
2. Radio: also similar ultra-tech comms using subspace, neutrinos or gravity ripples
3. Computers: including robots
4. Most advanced sensors: no RADAR, image intensifiers, multi-scanners, tricorders and similar
5. Most advanced transport: no on planet teleportation, anti-gravity vehicles
6. Other stuff: no recon drones, nanotech, advanced medicine

Specific points.
1. Getting from orbit to the surface
Some sort of simple re-entry vehicle without advanced (electronic or computer controlled) guidance or sensors (no RADAR altimeters). Also limited to chemical rockets (no anti-gravity). Controls would have to be mechanical, pneumatic or hydraulic.
Or maybe they can teleport/transport/transmat down but are then stuck.

2. Communications from surface to orbit
Optical or thermal? And likewise for the return leg.

3. On-planet communications
Any ideas? No radio so I assume they'll be limited to optical signal (light, flags, heliographs) and shouting.

4. On-planet transport
As far as I can see simple vehicles not using electrical systems should be OK. No spark ignition. Microlights for aerial recon.

5. Weapons.
Chemical firearms, explosives, various gases. No advanced sighting devices however.

6. General survival.
Bring your own food, water purification gear, oil lamps (or chemi-luminescents or radioactive decay glowpups), gather firewood (or bring nuclear heaters). No self-erecting tents or holobases.
Given the hostility of the (primitive) locals maybe some fortifications, concertina wire.

7. Getting back to orbit.
Well the plan is that our heroes will destroy the alien machinery and re-enable advanced technology. But I'm sure they'll want a backup plan. Just in case...
So, how do you get a group of about six people from the surface of a (roughly) Earthlike planet to low orbit (at least 250km) without using electrical or electronic systems? No electric fuel pumps, no RADAR, no computers, no radio..........
Also the craft needs to work without much infrastructure, so no multi-kilometre concrete runways.

Nuclear weapons.
This intrigues me. I don't see an implosion weapon, even one fabricated using very advanced tech, working without electrics. Unless some sort of pneumatic systems is possible for the explosive lens detonators. However a gun-barrel weapon should be workable; mechanical timer, percussion detonator et cetera.
Better be careful with it.
Likewise can anyone come up with a plausible method to store anti-matter without electricity or magnetic fields?


So, any advice, suggestions, comments?

Think 19th century basically. Note sure what was question or statement, so I'll go from one to the next.

1. Getting from orbit to the surface
Control is fine, but think about it, your main problem is not control but *calculating* the orbit reentry , so as to not burn or dislocate in the atmosphere. What use is it of control if you have no way of knowing the correct reentry points ? They would have to use big book with manual orbit entry listed in them or do orbital calculation (or at least their chars have the knowledge).

2. Communications from surface to orbit
Is the atmosphere transparent to infrared ? How is the weather ? If your planet is without weather but with high CO2 concentration and very hot, they might be betetr off some sort of optical message (burn a lot of stuff to form letters) but keep in mind that to see that even from LEO would necessite that the orbiting stuff has quite the optic.

3. On-planet communications
From line of sight of communication you got it. Also for local building wasn't there some form of tube pneumatic communication ? Or was it only for items ?

4. On-planet transport
from horse carriage to railway assuming there is a civilisation there.

5. Weapons.
OK as long as you allow fully optical advanced sighting device like telescope or similar.

6. General survival.
A friend got a nearly-self erecting tent. It is purely mechanical. It is a judicious the way it is done with only aluminium bars allowing for the tent to automatically open when you got the base done. Not sure how it works.

7. pure chemical rockets, calculated to ignite at various altitude, and separate once combusted. Think powder booster. But without electrical tech to help, they are in for decades or more of works, even if they have the necessary knowledge and calculation ready.

8. Nuclear weapon. one model is actually the half sphere or similar model. A canon explosively propulse two semi critical mass agaisnt each other together so that if put together they are critical. I can't remember if it is valid for plutonium based weapon only or which are the limitation.
ETA: loook up "little boy" http://en.wikipedia.org/wiki/Little_Boy

ETAETA : Oh I see that's what you meant with gun barrel weapon.

9. Anti Matter : Yes put your anti matter stuff in a anti matter vessel. *duck*.
Theoretically if you have a vacuum which can be maintained without electricity and a permanent magnetic field suspending the anti matter , assuming it is paramagnetic or something similar. I don't see it working but it is a role playing game, you might simply wave the detail.

 

[Toke]

Once they are in orbit they should be home free as the mothership will have no trouble finding them.

In trade school we made small sequential programs with pneumatic valves instead of electrical relays, and on a vessel I was on the propeller pitch had pure hydraulics analogue controls.
There were large handles on the centre console and in each bridge wing with a chain drive torch bar between them and to the analogue valve giving pressure signal to an amplifier at each propeller shaft.

It is amazing what can be done without electricity. (if you accept clunky and expensive)*

Still, don't let that prevent you from declaring that the lack of electrical process controllers and electric motors gives a economic advantage to coal powered steam technology.

*An older technology for ballast tank measuring were a thin pipe to the bottom of each, they were connected to manometers and had a slight air tickle applied.
The manometer would then display the water column in the tank. (with a back plate for the needle calibrated for tons in that tank)
Such a system is alot more expensive and complicated to install that wires with pressure sensors connected to the vessels computer system.

ETA:

Also for local building wasn't there some form of tube pneumatic communication ? Or was it only for items ?

I think it still exist in Prague, and the items are likely letters. (or nowadays memmory sticks. )

 

[catsmate]

Think 19th century basically. Note sure what was question or statement, so I'll go from one to the next.

Thank you, all contributions accepted.

1. Getting from orbit to the surface
Control is fine, but think about it, your main problem is not control but *calculating* the orbit reentry , so as to not burn or dislocate in the atmosphere. What use is it of control if you have no way of knowing the correct reentry points ? They would have to use big book with manual orbit entry listed in them or do orbital calculation (or at least their chars have the knowledge).

Perhaps a mechanical computer? Babbage engine built using nanotech for precision. Just to get the players down. I like the idea, it'll limit their gear and re-supply potential.
For the descent I think their course will be mostly preplanned, i.e. shoved from mother-ship on suitable trajectory with a list of times to fire rockets. And an accurate clock.

2. Communications from surface to orbit
Is the atmosphere transparent to infrared ? How is the weather ? If your planet is without weather but with high CO2 concentration and very hot, they might be betetr off some sort of optical message (burn a lot of stuff to form letters) but keep in mind that to see that even from LEO would necessite that the orbiting stuff has quite the optic.

I haven't decided on much of the planet's details yet, I'm thinking pretty desert like, little cloud. The guys in orbit would have equipment superior to today's best orbital surveillance gear (it's outside the planet's influence) and access to big light arrays for signalling.
Hell, they could deploy a large orbital mirror, that should impress the locals. "Fiat lux".

3. On-planet communications
From line of sight of communication you got it. Also for local building wasn't there some form of tube pneumatic communication ? Or was it only for items ?

Well the locals are (so far) tribal with a pre-gunpowder level of technology. It's more for the small team of characters, and their off-planet opposition.

4. On-planet transport
from horse carriage to railway assuming there is a civilisation there.

Hmmmm. This intrigues me, perhaps I'll move away from my original plan and have the locals more advanced rather than just annoying primitives with bows.

5. Weapons.
OK as long as you allow fully optical advanced sighting device like telescope or similar.

Well the locals have bows, not guns. So far anyway. The characters will bring anything they can fit in their craft.

6. General survival.
A friend got a nearly-self erecting tent. It is purely mechanical. It is a judicious the way it is done with only aluminium bars allowing for the tent to automatically open when you got the base done. Not sure how it works.

OK, thanks. I'll investigate that.

7. pure chemical rockets, calculated to ignite at various altitude, and separate once combusted. Think powder booster. But without electrical tech to help, they are in for decades or more of works, even if they have the necessary knowledge and calculation ready.

It's more for the heroes to make it off the planet if they can't fix the situation. They'd have it assembled off planet and landed in a similar manner to themselves. If their only way off the planet is a nuclear rocket of dubious capability it should concentrate their efforts.

8. Nuclear weapon. one model is actually the half sphere or similar model. A canon explosively propulse two semi critical mass agaisnt each other together so that if put together they are critical. I can't remember if it is valid for plutonium based weapon only or which are the limitation.
ETA: loook up "little boy" http://en.wikipedia.org/wiki/Little_Boy
ETAETA : Oh I see that's what you meant with gun barrel weapon.

Yeah, that was the design I was looking at. Possibly using Plutonium (if it's very isotopically pure) otherwise Uranium.

9. Anti Matter : Yes put your anti matter stuff in a anti matter vessel. *duck*.
Theoretically if you have a vacuum which can be maintained without electricity and a permanent magnetic field suspending the anti matter , assuming it is paramagnetic or something similar. I don't see it working but it is a role playing game, you might simply wave the detail.

Possibly. I think I'll drop that idea, unless one of the players comes up with a *very* good design. And tests it first. Would you want to be on a landing craft with such a device? What happens if you bang it hard enough?

 

[Floyt]

Re getting down from orbit - what makes re-entry difficult is generally orbital velocity, not altitude. If you are stationary relative to the ground, you can just jump and rely on a parachute once you hit atmosphere (as recently demonstrated by Whatshisname the Red Bull Flunky). And precise velocity matching is presumably not an issue for the tech that will be available while still in space.

 

[catsmate]

Once they are in orbit they should be home free as the mothership will have no trouble finding them.

Yeah, they'd need to make it beyond the atmosphere and they could be picked up.
Unless something goes wrong..........

In trade school we made small sequential programs with pneumatic valves instead of electrical relays, and on a vessel I was on the propeller pitch had pure hydraulics analogue controls.
There were large handles on the centre console and in each bridge wing with a chain drive torch bar between them and to the analogue valve giving pressure signal to an amplifier at each propeller shaft.

It is amazing what can be done without electricity. (if you accept clunky and expensive)*

Cool. I remember a bit about fluidic computing, mostly from reading about Phillips and his 'Glooper'.

Still, don't let that prevent you from declaring that the lack of electrical process controllers and electric motors gives a economic advantage to coal powered steam technology.

Well I'm still considering what technology the locals will have. I suspect I'll re-think the Planet of the Daleks idea of they being primitive savages. Perhaps more of a steampunk feel.

*An older technology for ballast tank measuring were a thin pipe to the bottom of each, they were connected to manometers and had a slight air tickle applied.
The manometer would then display the water column in the tank. (with a back plate for the needle calibrated for tons in that tank)
Such a system is alot more expensive and complicated to install that wires with pressure sensors connected to the vessels computer system.

Interesting, thanks.

I think it still exist in Prague, and the items are likely letters. (or nowadays memmory sticks. )

Still used in some large stores for moving cash and papers.

 

[Lukraak_Sisser]

If nuclear weapons work you could also have the players construct a vessel using nuclear bombs as a propulsion mechanism (Larry Niven used it in Footfall). The constuction, including the explosives needed to trigger the implosion could all be done off planet with a complex (and fragile, and very prone to error) pneumatic chemical system.

A 'kind' GM could of course also allow the players to find an abandoned spaceship from whoever built the handwavium machine in the first place in case all their plans fail.
What could possibly go wrong with an unknown spaceship with unknown controls?

As for on planet communications, don't forget good old smoke signals/morse combo.
Chemoluminescence might be used to make night heliographs.

Also, even if the locals are in the bow/arrow timeframe, if they have any form of civilization, especially with riding animals, they should be able to communicate within a continent with only a few weeks lag, less if a true government and road network exists.
Even in the bronze age trade stretched from europe to the middle east in quantities. The Romans could get word across the empire in under a week or so (by riding couriers and horses to exhaustion). In the 19th century this was even faster.
A spaceship landing won't be a secret for very long.

 

[Blue Mountain]

Interesting topic. My father, now 87, grew up in a world without electricity on a farm in western Canada. (Rural electrification wasn't complete until after WW II.) For motive power they relied on horses and mules, and they had bicycles. My father says they had a small gasoline engine that my grandfather didn't like very much.

In the United States, Amish and certain old order Mennonite communities also reject electricity, but often do very interesting things with compressed air.

As far as computers go, check out the Babbage's Analytical Engine. This was a design for a fully functional computer that was implemented entirely mechanically. Despite stories to the contrary, the tech of the era was up to building it, but the Royal Navy's patience with Babbage had run out, and with it their funding.

Later there came the Harvard Mark 1 that was used to calculate ballistics tables (sounds like a problem your gamers need to solve ...) It, too, was primarily a mechanical device that used an electric motor for power, although the Wikipedia article says it also used a lot of wire, which indicates a significant electrical component.

You can do some pretty amazing things with purely mechanical devices. The IBM Selectric typewriter was one such device. Yes, it had an electric motor in it, but all it did was drive the mechanics. I suspect a modern modder could get one to work with a hand crank.

 

[catsmate]

Re getting down from orbit - what makes re-entry difficult is generally orbital velocity, not altitude. If you are stationary relative to the ground, you can just jump and rely on a parachute once you hit atmosphere (as recently demonstrated by Whatshisname the Red Bull Flunky). And precise velocity matching is presumably not an issue for the tech that will be available while still in space.

Good point. They could do the difficult part beyond the effect of the clarketech and drop.

If nuclear weapons work you could also have the players construct a vessel using nuclear bombs as a propulsion mechanism (Larry Niven used it in Footfall). The constuction, including the explosives needed to trigger the implosion could all be done off planet with a complex (and fragile, and very prone to error) pneumatic chemical system.

I'm a little reluctant to go as far as a nuclear-pulse drive system. The bomb was intended to destroy the "alien city". After all the Daleks did it with a couple of small-ish bombs.

A 'kind' GM could of course also allow the players to find an abandoned spaceship from whoever built the handwavium machine in the first place in case all their plans fail.
What could possibly go wrong with an unknown spaceship with unknown controls?

Would you like that list in alphabetical order, probability of occurrence or probability of causing messy death.

As for on planet communications, don't forget good old smoke signals/morse combo.
Chemoluminescence might be used to make night heliographs.

Well they'll have oil/carbide lamps at lease. Maybe some gas tubes with a synthetic radioactive (something like 242Cm) as the power source.

Also, even if the locals are in the bow/arrow timeframe, if they have any form of civilization, especially with riding animals, they should be able to communicate within a continent with only a few weeks lag, less if a true government and road network exists.

Hmm. I think I'll need to reconsider them in depth. Originally they were just a background nuisance. Perhaps something more like The Sorcerer's Apprentice.

Even in the bronze age trade stretched from europe to the middle east in quantities. The Romans could get word across the empire in under a week or so (by riding couriers and horses to exhaustion). In the 19th century this was even faster.
A spaceship landing won't be a secret for very long.

Which opens up further interesting possibilities, especially with more than one off-planet group arriving. No Daleks though.

 

[Roboramma]

How advanced is their technology?

The brain is a type of computer, and presumably it works on this planet

Can they build a "biological computer" to take with them for their computing needs?

 

[Myriad]

Mechanical analog fire control computers! http://www.eugeneleeslover.com/VIDEOS/fire_control_computer_1.html

The design and machining of these devices requires elite master craftmanship, but the necessary tooling can be steam powered.

However, you do not want to have to try to design your escape craft to be able to carry one of these to stay on course.

Mechanical digital computing might be feasible but was never explored in any serious way until very recently (with the Clock of the Long Now design). Computers went electric before they went binary.

Respectfully,
Myriad

 

[Hellbound]

Communications/travel:

Hot air ballons. The locals, if more advanced, would likely be at hot air balloons and blimps stage. Possibly propeller planes. I dunno how possible a jet would be to make without electronics...I suspect somewhere between "winning the lottery" and "suddenly becoming the object of the affections of every supermodel in the world".

But anyway, balloons are definately an option for signalling for your characters. Signals are pretty well limited to line of sight. Easy way to increase range is to increase height. A small balloon carrying a signal flare could be used for longer range signals. Basically, the balloon would have a small, shuttered box under it with the flare. THe flare could provide the heat for it to rise, as well as signal. A cable to hold it above your location, with a second string that can be used to open/close the shutters. Reuseable by replacing the "flare" cartridge.

ETA: For that matter, your characters might want to carry a hot air balloon kit with them. Depending on the wind situation on planet, of course

Speaking of wind, kites are another option for signalling (similar idea to the balloons above).

Actually, just basic "shoot into the air" signal flares are an option, as well. Fireworks of all sorts were often used for signalling. Color, number, timing between shots, and type of shot can all be used to encode info. Replaced with colored smoke during the daytime (or colored balloons...might even be able to rig up something under the balloon that woudl act like a small set of semaphore flags).

 

[catsmate]

How advanced is their technology?

The locals? Not sure yet. I'd planned on going with the original DttD level of late stone age. However I'm inclined to change this after the feedback here.

The brain is a type of computer, and presumably it works on this planet

Can they build a "biological computer" to take with them for their computing needs?

Hmmmm. Possibly, I'd considered a couple of bits of biotech. However how'd you handle I/O with a biocomputer?

Mechanical analog fire control computers! http://www.eugeneleeslover.com/VIDEOS/fire_control_computer_1.html

The design and machining of these devices requires elite master craftmanship, but the necessary tooling can be steam powered.

Well the characters have access to nanotech so building the machine, using very advanced materials, shouldn't be a problem. As long as it operates without electric power.

However, you do not want to have to try to design your escape craft to be able to carry one of these to stay on course.

Mechanical digital computing might be feasible but was never explored in any serious way until very recently (with the Clock of the Long Now design). Computers went electric before they went binary.

Yeah, any mechanical computer would have to be very simple or very bulky. However a single-task analogue machine for handling the flight *shouldn't* be impossible.

 

[catsmate]

Communications/travel:

Hot air ballons. The locals, if more advanced, would likely be at hot air balloons and blimps stage. Possibly propeller planes. I dunno how possible a jet would be to make without electronics...I suspect somewhere between "winning the lottery" and "suddenly becoming the object of the affections of every supermodel in the world".

I'm very dubious about jets without electrical controls somewhere in the loop.
Airships shouldn't be a problem. The first dirigibles flew in the 1860's, with or without engines.
Actually this gives me an idea for an airship kit. Easy assemble frame made from advanced polymers, ultra-tech "foamed vacuum" for lift and a simple steam turbine for power.

But anyway, balloons are definately an option for signalling for your characters. Signals are pretty well limited to line of sight. Easy way to increase range is to increase height. A small balloon carrying a signal flare could be used for longer range signals. Basically, the balloon would have a small, shuttered box under it with the flare. THe flare could provide the heat for it to rise, as well as signal. A cable to hold it above your location, with a second string that can be used to open/close the shutters. Reuseable by replacing the "flare" cartridge.

Excellent idea. Possibly multiple flare/smoke rounds to give a number of options.
Or even a balloon mounted light with a mechanically operated shutter controlled pneumatically from the ground.

ETA: For that matter, your characters might want to carry a hot air balloon kit with them. Depending on the wind situation on planet, of course

Yes I suspect they'll be packing very carefully, hence I like the idea of a limited weight allowance.

Speaking of wind, kites are another option for signalling (similar idea to the balloons above).

And probably more portable.

Actually, just basic "shoot into the air" signal flares are an option, as well. Fireworks of all sorts were often used for signalling. Color, number, timing between shots, and type of shot can all be used to encode info. Replaced with colored smoke during the daytime (or colored balloons...might even be able to rig up something under the balloon that woudl act like a small set of semaphore flags).

Ah, you'd already thought of my idea. Sorry I didn't read your post fully.
Excellent potential there.

 

[bruto]

Old science fiction scenario, look for a book from about 1964 called The Day the Machines Stopped. Since I have not read it since the 1960's I don't recall how they managed by the end to blow up the offending "anti-electricity" machine, but they did, or it's assumed they were about to.

There was also a SF book called Pavane based on a repressive society in which most modern technology was forbidden. Long time since read, but I seem to recall they got around some problems with semaphores and wind powered vehicles and other amusing devices.

Of course some of the ingenious workarounds in the first book may not work if they don't already exist, e.g. steam locomotives and diesel trucks. But if one has a lot of resources and time, a steam engine can get a lot of things done.

Back a few decades ago, Popular Science and the like were hot for fluidics, but I don't know what progress has been made since. As mentioned above, the basic computational gates can be made with hydraulic or pneumatic valves.

 

[Dr. Keith]

Would diesel engines work? No spark needed and fuel could be locally processed food oils, although that might strain the local processing capacity.

(derail: this was the first thing that irritated me about the tv show Revolution- where did all the old diesels go? I was willing to let it go until the steam engine showed up. Somehow that put it over the edge for me. Sorry.)