Electric Engines to leave Eve

[kerbalfreak]

I already made a Eve and back mission in stock 1.3 KSP. Yes, it was to prove to myself that I could, because when I played for the first time it seemed something impossible. It was a real pain, but very satisfying.

Now I'm playing with mods that I think are balanced or with things that make sense. Always bordered me that the game didn't have any electric engine, that could run only in intake air and EC. Looked at a lot of mods, and liked the most one of Nertea MK4 Spaceship. It uses 200 EC/S, which is manageable with Near Future batteries and reactors, but I don't think it is unbalanced. I find very fun to make Eve airplanes, VTOLs and quad-copters instead of rovers.

Now I'm thinking of making a vehicle that uses electric engines in it's first stage, maybe an SSTO. Here's a pic of the very first concept (just to see what it could lift, MechJeb predictions don't work with this engine):



It goes up slowly, reaching 1.0 TWR at about 30 km, with around 80 m/s. It was able to lift a decent tank with a aerospike, with 4000 m/s of delta-v.

Now some questions...

Anyone has made something like this? Should I make it a airplane, a VTOL? Two, three stages? How about a SSTO? If so, how to reentry safely?

I was thinking of this (for and SSTO):

First: electrical fans go to 30 km, using batteries, mitigated by a nuclear reactor.

Second aerospike to gain more altitude and starting circularizing.

Third: ion engines, using the battery that was charged by the nuclear reactor while the aerospike was running. Any alternator in engines will make almost no difference in this...

Mod's I pretend to use: Near Future Techs, by Nertea, and some moderately tweak scale.

Hope this section of the forum is the most appropriated for this topic.

Thanks!!

[TheProtagonists]

For SSTOs I think it's probably better to use OPT's electric engines in atmosphere. They use significantly less EC (through still a lot) for quite a lot more thrust, and they function through the entire atmosphere and can put a craft into a pretty high apoapsis. However I'm not really sure if they work well under dense atmospheres since they produce more thrust the thinner the atmosphere is.

[Urses]

I think it belongs more in "Game Quesrions" section.

But @topic if you try this in this ascend profile you need big amounts of LFO as you need to reach a prolonged suborbital trajectory that skips out of atmo. As Ions are realy slow.

As plane it would be a little easier i think. As you can try to step ascend to around 20 km and beginn a speedrun in shallowed out trajectory as every horizontal m/s saves you lots of dv for aerospikes. It is an interesting idea, But at the momwnt it looks like you can better advence with a ballon supported platform as lifter and start a rocket at maximum hight from there?

For an SSTO you have realy big mass as dead wight, reactor, fans and ions for the aerospike phase and there you have to reach around 75% of the circularisation speed.

Edited November 19, 2017 by Urses

[bigcalm]

Actually, this might be a really good idea.  I've built an electric prop plane for Eve in the past - this wasn't ever intended to do anything apart from fly about slowly near the surface and explore, but it might be possible to scale it up.  On board is a 1.25m nuclear reactor from MKS to power it, plus 2 electric propellers from the SXT mod for propulsion.  It even has a small amount of fuel on board as I needed some ballast to get the centre of mass / centre of lift in the right places.

I'm just testing to get some parameters here from my existing plane. 

* It really needs to be very aerodynamic - if I try to fly with the cargo bay open at ground level, it rapidly loses speed below stall speed and goes into a nose-dive.  Even with the cargo bay closed it won't get much above 50ms in level flight at ground level.  Even at 15k altitude I'm struggling to get past 70 ms.

* I can run the reactor at 5% power with the two electric props running on full power.  This means I can have at least 20 times the number of electric propellers without having to increase the size of the on-board reactor.

* I can reach at least 20k altitude.  It climbs slowly.  Really really slowly.  I launched the plane, started writing this post, and it's only just reached 15k altitude after about 15 minutes on4x physics-warp.  I think it'll get to around 20k eventually, possibly higher.

* Putting the wings, engines, reactor and other things on decouplers might make it even more draggy.  Not good, but maybe we can avoid making it really draggy with clever design.

How much delta-v do I need to get from altitude of 20k on Eve into orbit?   Assume a standing start.

 

 

[JadeOfMaar]

On 11/18/2017 at 9:29 PM, TheProtagonists said:

For SSTOs I think it's probably better to use OPT's electric engines in atmosphere. They use significantly less EC (through still a lot) for quite a lot more thrust, and they function through the entire atmosphere and can put a craft into a pretty high apoapsis. However I'm not really sure if they work well under dense atmospheres since they produce more thrust the thinner the atmosphere is.

There are two such engines, the (short) WarpJet S.A.G.E. and the (long) WarpJet S.U.R.G.E.

The SURGE is a main engine specifically made for use on Eve and other high-gravity planets. It's as powerful at Eve sea level as it is near vacuum. The SAGE only works well in thin atmo so it's a great upper-stage booster for Eve ascent vehicles.

[BRAAAP_STUTUTU]

On ‎11‎/‎21‎/‎2017 at 9:30 PM, JadeOfMaar said:

There are two such engines, the (short) WarpJet S.A.G.E. and the (long) WarpJet S.U.R.G.E.

The SURGE is a main engine specifically made for use on Eve and other high-gravity planets. It's as powerful at Eve sea level as it is near vacuum. The SAGE only works well in thin atmo so it's a great upper-stage booster for Eve ascent vehicles.

Yeah,I tested the SURGE yesterday and achieved kerbin espace velocity and almost had an encounter with eve, was not prerpared for how monstrously powerful that thing was...

[JadeOfMaar]

@RobinVerhulstZ  It's not quite OP to hell, however, if you start playing with Sigma Dimensions. The WarpJets are also intended for use in real-scale.