Pushing the boundaries of Eve spaceplanes

[camacju]

Ok, I'm not sure if this is a good topic for this forum because it might or might not be possible.

I was playing around with some Eve SSTO designs and got this:

Spoiler

This craft uses a single Vector engine for the ascent - no propellers. It actually has enough payload capacity to fit in some ion propulsion and go all the way back to Kerbin.

This alone is nothing new - Brad Whistance did it years ago. But this is a much lighter design and has a greater payload fraction, which leaves another possibility.

The main question I have is:
Is it possible to go from Eve's surface to Kerbin's surface in a single stage, with no propellers and no ion engines?

I've done some calculations and it seems like it may be possible, especially if the craft is scaled up and a Mammoth engine is used instead of four Vectors. I know that it's possible to go from Eve to Kerbin with propellers and no ion engines, but propellers definitely make the challenge easier. I think this will push right up against the limit of what's possible on a purely rocket-powered Eve plane.

More detailed rules:
-The craft should be able to start on the surface of Eve (stationary) and end up stationary on the surface of Kerbin.
-No staging (also: no docking with or clawing anything, no burning off parts or removing them through EVA construction)
-No ion engines (because we already know that's possible)
-No propellers (Stock props should already be disallowed through the no staging rule, so just don't use any parts from the Breaking Ground dlc. If there are any loopholes they will be patched)
-ISRU optional (you can edit the craft to Eve's surface if you want) but if you manage to take a set of ISRU equipment as well then I will be impressed.

[Poppa Wheelie]

16 hours ago, camacju said:

I was playing around with some Eve SSTO designs and got this:

 

Can you give some detail on what we're looking at here?  I think I see some fairings and clipping at the front, but can't really tell what's going on.  Two blue stripes up front - is that a kerbal helmet?  More fairings at the back?  Maybe you're doing some things with the fairings to reduce drag?

Any details you feel like providing would be great.

[camacju]

3 hours ago, Poppa Wheelie said:

I think I see some fairings and clipping at the front, but can't really tell what's going on.  Two blue stripes up front - is that a kerbal helmet?  More fairings at the back?  Maybe you're doing some things with the fairings to reduce drag?

One fairing is the entire fuselage of the craft. Fuel tanks are clipped inside the fairing along with the vector engine. The blue stripes up front is an ISRU module because I was trying to do a full self contained mission at the time.

The fairing is the root part of the craft so drag is reduced but this is probably not strictly necessary.

 

[ItanMark]

Seems like fun! Ima try and do it via mining on Gilly.

[ItanMark]

[UPDATE] How do you guys even do a normal eve ssto?  At first glance it looks impossible☹️

[camacju]

On 9/2/2023 at 12:32 AM, ItanMark said:

Seems like fun! Ima try and do it via mining on Gilly.

It's actually a lot easier to skip Gilly entirely and just go direct, you'll use more fuel slowing down to land than just continuing your escape burn.

2 hours ago, ItanMark said:

[UPDATE] How do you guys even do a normal eve ssto?  At first glance it looks impossible☹️

There are a few different ways to do it. Since this challenge requires no propellers, I would suggest starting with one of Astrobond's designs:
 

Spoiler

 

 

From there you can tweak ascent profile, wing area, and thrust-to-weight ratio. Try to get as much payload in orbit as you can.

Another thing to try is to assist the ascent with nuclear engines. If you fill the wing tanks with liquid fuel, you can have zero additional dry mass (besides the engine), which is nice.

[Donmy Kerman]

@camacju I was wondering where you landed your Eve SSTO.

[camacju]

1 hour ago, Donmy Kerman said:

@camacju I was wondering where you landed your Eve SSTO.

Latitude -25, longitude -158.5

Pretty sure this is the tallest mountain on Eve and it's got a nice smooth takeoff area

[Hotel26]

4 hours ago, camacju said:

Latitude -25, longitude -158.5

Yeah, wiki: "The highest peak on Eve since version 0.21.1 is 7540 m high, found near (25° S, 158.5° W)".

I just sent a Tardis 2 exploration vehicle there (7506m, dubbed "Eve Max") and am waiting for sun-up to find the exact top.

25S is a long way from the equator.  Is that much of a handicap for ascent?

I have a base (so far unused) on top of Mauve Mountain, located at -0.52 +167.51 6415m, which I had selected for equatorial launch...

Spoiler

            name = Eve Max Tardis
            lat = -24.9934
            lon = -158.4754
            alt = 7541.2  [CoM of Tardis]

 

Edited September 6, 2023 by Hotel26

[Donmy Kerman]

@Hotel26 Eve's rotational velocity at the equator is only about 50 m/s, so the mountain being 25 S means a 4m/s loss. This is not a handicap for ascent.

13 minutes ago, Hotel26 said:

25S is a long way from the equator.  Is that much of a handicap for ascent?

[ItanMark]

On 9/4/2023 at 7:36 PM, camacju said:

It's actually a lot easier to skip Gilly entirely and just go direct, you'll use more fuel slowing down to land than just continuing your escape burn.

There are a few different ways to do it. Since this challenge requires no propellers, I would suggest starting with one of Astrobond's designs:
 

  Hide contents

 

 

From there you can tweak ascent profile, wing area, and thrust-to-weight ratio. Try to get as much payload in orbit as you can.

Another thing to try is to assist the ascent with nuclear engines. If you fill the wing tanks with liquid fuel, you can have zero additional dry mass (besides the engine), which is nice.

Thanks! Gonna be trying to do it with similar aircrafts as in the tutorial:)