# Could electric fans lift a rocket strait up like a multi propeller drone? [closed]

Could electric fans like the ones below lift a rocket? What is the amount of electricity needed to lift a interplanetary rocket?

Could a nuclear power plant provide enough electricity?

https://en.wikipedia.org/wiki/Airbus_E-Fan

I added the pictures and link to show people who are not familiar with electric propellers and impellers an idea of what is available. I do wonder if these types of engines have enough thrust to vertically lift anything?

• I, personally, have no idea what you are talking about. Can you explain this concept a little better? What does the tower do? – Organic Marble Sep 12 '18 at 20:27
• Well, the Falcon Heavy has total takeoff thrust of 5,100,000 lbs with both boosters and the core running flat out. The GEnx jet engine puts out about 70,000 of thrust. So you would need 73 of them to equal the same thrust. The electric power requirements are going to be impressive. Each engine is about 20 megawatts, so you are going to need 1.5 gigawatts. At 100,000 volts you are going to need 14,600 amps. This will be difficult to deliver. Bottom line is this is impractical. – zeta-band Sep 12 '18 at 20:34
• A turbine extracts energy from a flowing fluid and it converts the energy to mechanical work--it turns a shaft. An engine releases energy by burning fuel, and converts the energy to mechanical work. What does "electric turbine engine?" mean. – user27176 Sep 12 '18 at 20:39
• Also, your questions keep referencing this magic number, 53km. What's so special about 53km? – user27176 Sep 12 '18 at 20:41
• @Muze trying to do a sliding contact at 14,000 amps is going to give you arcs that will blast everything into plasma. Plus the 73 engines are going to weigh really a lot. You keep adding weight and complication to try to save a little fuel. It won't make things better. – zeta-band Sep 12 '18 at 20:53

Turbines don't work in the space, there is no air.

It might be usable as the first stage of an orbital, or suborbital vehicle.

The main problem with it is not the energy source, but that the size of the drives are too big.

The maximal lift mass of the largest plane ever built, the Antonov An-225, is 640tons. A Soyuz total mass is around 300 tons, more than half of it is its first stage.

However, the maximal speed of the Antonov is around 800 km/h, which is nowhere from the some km/s speed of a Soyuz after its burned out first stage.

To have a supersonic first stage is not impossible, mainly engineering reasons are avoiding it (it could work, but with rockets can go better). And note, we have very few technology to build large supersonic crafts. The largest is the Tupolev Tu160, a Russian strategic bomber, its maximal takeoff weight is 275 tons.

• Add a problem of energy density. Hydrolox offers 15.8MJ/kg and is expelled as it burns. Best Li-ion batteries have 0.72MJ/kg and are a little too expensive (and dangerous) to drop the depleted ones throughout the flight. – SF. Sep 13 '18 at 9:03
• doesn't use batteries direct electricity hypothetically – Muze Sep 13 '18 at 10:17
• @Muze: How? Dragging wires behind? – SF. Sep 13 '18 at 11:03
• @Muze you seemnto mix height and speed. For travelling to the moon, or other planets, you need speed. Imagine sitting in a giant soup bowl 200000 kilometers across. It has no friction, but it is huuuuge. To get out, you can bowl a ball really fast, and it will spiral out of the bowl eventually. The atmosphere is a teeny tiny patch in the middle of the bowl that has friction. Your tower, or a plane, will only move your bowling position halfway out of this patch, but give you virtually no help in accelerating the ball. All that energy for that titanic push still has to come from you (the rocket) – bukwyrm Sep 13 '18 at 15:04
• @Muze: It wouldn't eliminate even 1/4 worth of a stage - replacing all the savings with a massively complex "electric fans" stage. It's like building 50 meters of escalator at the foot of Mt. Everest to make climbing it easier. – SF. Sep 18 '18 at 10:59