There is a wandwavium in this planet that makes some islands float, it is really difficult to mine. When it has the appropriate treatment, it becomes a reactionless drive.

This drive consumes electrical energy and it converts in kinetic energy, they use this to create some flying ships. In non relativistic speeds, the conversion efficiency is super high, so it is more efficient than, let's say, an turbo prop or anything we use in modern airplanes. The more speed you have less efficient it is, so I won't need to bother having more kinetic energy in the ship than energy needed to run the drive, like this post about killing machines and perpetual motion stuff.

The origin of the electrical energy to the drive comes from thermal engines, like diesel or gasoline engines, that moves an generator. So without oxygen, the ships won't work as they don't have solar or atomic energy. This way the ships only work on the atmosphere. I suppose they could use an solar sterling engine to create an spacecraft, but, for now, only atmospheric ships.

What would they look like? Airplanes with less complicated drives? A lifting body without wings, like this nasa wonderful ship. Would they even need flaps to control the attitude of the ship if they can accelerate in whatever direction the reactionless drive is pointing?

They will look like an spaceship with multiple drives pointing in different directions so it can accelerate to whatever they want. If i am being too vague i can explain more, I just don't want do bore you to death with irrelevant details. The point is how they would look like being designed to work in a atmosphere similar to our own in relation to other non atmospheric scifi reactionless drive spacecraft.

  • $\begingroup$ How a thing looks is a function of its design specifications. How fast are those ships supposed to go? How big are they? How "more efficient" are those drives, and how do you measure their efficiency? (This is not a trick question; think hard about what is to be understood by the efficiency of an aircraft engine. Hint: consider the situation where the aircraft starts moving from zero speed.) (Ah, and take care that "Kinect" is a Microsoft trademark. You probably want "kinetic", which is a Greek word meaning "related to motion".) $\endgroup$
    – AlexP
    Commented Jul 5, 2020 at 19:17
  • $\begingroup$ Do your wandwavium thrusters only work in one direction? Also, what technology level are you talking about--clearly electricity and combustion engines exist but do you have integrated circuits? $\endgroup$
    – Dragongeek
    Commented Jul 6, 2020 at 14:19
  • $\begingroup$ Sorry about the Kinect name instead of kinect, english is not my first language. The ships go as fast as the power input of them, but the power weight ratio is limited by the efficiency of the generator. Being diesel i think the most speed a vehicle can go will probably be comparable with prop or turboprop engines. The "efficiency" i am talking about electric energy in and kinectic energy out. An electrical motor effiency (joules in to joules out) is about 75%. With this drive we will be loking at 95% at least. $\endgroup$
    – Surian
    Commented Jul 6, 2020 at 15:09
  • $\begingroup$ Yes it only works in one direction. They don't have integrated circuits but they do have some simpler electronics devices like generators, capacitors, inductors for exemple. The "thrust" of the engine being the power modulation of energy is made by the use of a variac power supply. No diodes tho. $\endgroup$
    – Surian
    Commented Jul 6, 2020 at 15:12
  • $\begingroup$ The whole oxygen-breathing thing falls apart when you introduce solar cells which also generate electricity. However, you don't have to worry about this going into space because of your clever efficiency argument. Space is mindbogglingly huge, and something going at a paltry 100mph would be so slow that I'd expect many to just treat it as standing still for all intents and purposes. Wake me up when it's going 10,000mph! $\endgroup$
    – Cort Ammon
    Commented Jul 6, 2020 at 16:41

4 Answers 4


The point is how they would look like being designed to work in a atmosphere similar to our own in relation to other non atmospheric scifi reactionless drive spacecraft.

You would want to minimize atmospheric drag, so the vessel would probably be drop-shaped, or avocado-shaped. This might just be a sort of shield cover made of waxed cloth, while the "real" vessel inside has a different shape.

Then, you need to take off and land, and here it depends - if it is simple to have several small engines, you would want to have some of them oriented downwards to negate gravitational pull, and at least two as far as possible from the vessel's center to provide steering and propulsion in the simplest way possible.

But if it is very expensive to have several smaller engines, then you'd go for a single large engine, mounted on gimbals, with the rest of the vessel gyroscopically stabilized. Much more complicated but cheaper.

Or you might go for a single engine thrusting backwards, relying on wings, fins and ailerons to provide direction. This means you need a runway to take off and land.

In all cases you would find it worthwhile to have at least wings, to increase the propulsive efficiency.

So, your vessel would resemble... an airplane. Or, depending on the devices' power, a blimp with wings, something like a Tiger Moth but without propellers (the propellers would be your reactionless impellers instead).

Unlike the Tiger Moth, not having buoyancy per se, your plane could not stop its impellers and land floating down. It could (but it would probably be a risky manoeuver) rise high, turn the impellers off, rotate them downwards and ride them down. This, again, would only be practical if the impeller thrust could be modulated efficiently.

enter image description here

  • $\begingroup$ This is what i am looking for. A blimp with wings. pḉçççççççnbbbbbbbbbb89 $\endgroup$
    – Surian
    Commented Jul 6, 2020 at 16:02

Electrostatic propulsion.


The first ever “solid state” plane, with no moving parts in its propulsion system, has successfully flown for a distance of 60 metres, proving that heavier-than-air flight is possible without jets or propellers. The flight represents a breakthrough in “ionic wind” technology, which uses a powerful electric field to generate charged nitrogen ions, which are then expelled from the back of the aircraft, generating thrust.

Your mystery element uses electricity to efficiently ionize air. Another chunk of it at the back of the plane operates on reverse polarity and serves to attract the ions. The ionic wind entrains ambient air and produces thrust and lift.

Some consequences of this mode of propulsion.

  1. Slow starting! You might want to use your diesel motor to turn a propellor until you were up to speed.

  2. It might work better at faster speeds. If this stuff can really impart a lot of charge to air, too much charge might exceed the dielectric strength of the air and cause a spark. But as more air volume is moving thru at higher speeds, there is more air available to carry the charge and so the machine can add more. This ionic wind mechanism has no moving parts and could potentially move a serious amount of air. The top speed of the vehicle will be determined by something other than the engine - probably aerodynamics.

This "ionic wind" idea is one of my favorites. More reading on the WB stack.

Realistic hovering mechanism for my sci-fi drone

How could a lightning magic user fly?

Actual scientific requirements for human flight

Can I make my drone swarm quieter or Silent?

  • $\begingroup$ It looks more like an Em Drive than an electrostatic propulsion. Being reactionless there is no air being pushed behind the aircraft. $\endgroup$
    – Surian
    Commented Jul 6, 2020 at 15:04
  • $\begingroup$ You are right. True reactionless drive is a hard target. $\endgroup$
    – Willk
    Commented Jul 6, 2020 at 21:32

Woodward Mach Effect Drives / White Quantum Vacuum Plasma Thruster

Two concepts are being considered that take advantage of how mass changes when it is accelerating.They propose two vibrating masses (which would then be sinusoidally adding or losing mass). The system is pushed apart when the pair is aligned in the direction of desired motion, and the system is allowed to restore when not aligned with the direction of motion.

The result is something like a transistor : allowing thermal energy (as kinetic energy) to gate into the system in only one direction.

enter image description here

If this is your reactionless drive it would take the form of a device that can be located anywhere. In fact, it would be best positioned at the center of mass for the vessel it's pushing, so that thrust can easily vectored by rotating the engine.


Another reactionless drive being considered is an evolution of the lightsail. The concept, super simplified is a lightsail carrying it's own light source.

enter image description here enter image description here

If this is your reactionless drive it would take the form of a device as pictured above. It can be located anywhere. In fact, it would be best positioned at the center of mass for the vessel it's pushing, so that thrust can easily vectored by rotating the engine.

  • $\begingroup$ It looks more like a Emdrive in the sense that it will point at the center of mass and be vectored,. The working princible tough is much more esoteric with no real science involved. You plug it in and voila, thrust. $\endgroup$
    – Surian
    Commented Jul 6, 2020 at 15:03

I fooled around with an idea like this a few years back, and your aircraft will probably...look like aircraft, just without what we'd consider normal propulsion units.

The reasons are twofold: the first is that if you can leverage aerodynamics, you need less of the handwavium per vehicle, thus allowing more vehicles, or alternatively larger vehicles for the same amount of material, because you don't necessarily have to lift the entire mass of the vehicle just from the handwavium. In some operations carried out today by helicopters, or things where VTOL would be really useful, say military airlift or disaster response, you would likely see specialized aircraft that could do that, but for long-haul routes something like a normal aircraft would be most efficient if for nothing else than you don't need as powerful as a generator.

The second reason is that if for some reason your generator goes down, an aircraft that uses aerodynamics can still glide and control their descent.

  • $\begingroup$ The real question for me is that usual aircraft have big wings because they relly on aerodinamics all the time to land and launch, but with the wandwavium in a VTOL configuration this is not needed. So a blimp with wings like the friend said or a lifting body has more space to put, say, cargo or MOAR GUNS. The gliding stuff is a thing to consider that i did not think about. I was imagining it more like an helicopter that just fall down if it has a mechanical failure. $\endgroup$
    – Surian
    Commented Jul 6, 2020 at 20:34

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