DAL59

SSTO Eve no docking or refueling

Recommended Posts

11 minutes ago, EvermoreAlpaca said:

Months behind on this response, but this video WAS in the new atmosphere.

And yes, leaving an asteroid in orbit is roughly the same concept of leaving a fuel tank there, but I would like to think it was a fun loophole.

As to making it to Gilly from Eve on one stage, without refueling, it isn't possible unless a glitch is used.  Or some kind of extreme lateral thinking solution.  Using the conventional approach, I haven't been able to manage more than a few hundred m/s dV from LEO.

Are you sure it was 1.2? This was made really shortly after the release. 

Share this post


Link to post
Share on other sites
Posted (edited)
Just now, Kergarin said:

Are you sure it was 1.2? This was made really shortly after the release. 

It got easier in 1.2!  I originally built the craft before 1.2, but the changes in that patch improved performance.

Edited by EvermoreAlpaca

Share this post


Link to post
Share on other sites

At Eve's high point, it got harder in 1.2.   Your video must have been with version 1.1.3

Share this post


Link to post
Share on other sites
Posted (edited)
Just now, OHara said:

At Eve's high point, it got harder in 1.2.   Your video must have been with version 1.1.3

I have a design i'm working on at the moment that gets a lot more payload to Eve orbit in one stage than anything I had achieved in 1.1.3.  It is somewhat easier than before.

Vertical takeoff style is certainly harder than before.

I think this means I need a video on this =)

Edited by EvermoreAlpaca
  • Like 2

Share this post


Link to post
Share on other sites
3 minutes ago, EvermoreAlpaca said:

I have a design i'm working on at the moment that gets a lot more payload to Eve orbit in one stage than anything I had achieved in 1.1.3.  It is somewhat easier than before.

Vertical takeoff style is certainly harder than before.

The pressure at the lower atmosphere was drastically increased in 1.2. I did test this with probes and created a chart. (will see if I can find it)

So the engines have less output and therefore a worse twr than before.

Also the drag increases, you have to deal with more friction and heat.

My ssto lander had a ridiculous amount of payload in 1.1.3. But in 1.2 it could not even make it to orbit anymore. Even not if totally stripped down.

 

So vertical takeoff is way harder now. I have to say, I did never test planes on Eve in 1.2, because I learned in 1.1.3 that vertical takeoff on Eve is much more efficient than SSTO planes in horizontal takeoff.

So maybe due to the ticker atmosphere wings do now have more lift, and maybe things have changed and planes are more efficient now, and maybe work even better in 1.2 and above than in 1.1.3?

 

How do you know it's 1.2 in the video? Or are you Bradley?

Share this post


Link to post
Share on other sites

This is Bradley =)  The craft in that video works in both 1.1.3 and 1.2, but it works a shade better in 1.2  IIRC, I took some fuel out in the 1.2 variant.

  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)
58 minutes ago, EvermoreAlpaca said:

This is Bradley =)  The craft in that video works in both 1.1.3 and 1.2, but it works a shade better in 1.2  IIRC, I took some fuel out in the 1.2 variant.

Ah... Hello =) didn't know this, now things make more sense :D

Have found the chart i was talking about. It was not about pressure but about the mammoth engines thrust.
S7xD9DN.png

It's around 8% loss at launch.
I did not expect that the better workings wings can compensate this that well. But obviousley they do verry well :o

I should have realized this, wehen @astrobonddid build the smalles Eve SSTO i have seen so far. It's also a plane, and it Shows how small wings can be now
https://www.youtube.com/watch?v=8Q-PJ4FgWpg&t=34s

 

So Maybe you can even scale yours down now in 1.2+?

 

If i ever find the time for Eve SSTOs again, I will definitely also try planes again :D

 

PS: did you know about this? Was a little frustrating seeing this. :D But great work anyway and thanks for the mention (I think you meant my SSTO?) :)

 

 

Edited by Kergarin
  • Like 2

Share this post


Link to post
Share on other sites
14 hours ago, Kergarin said:

Ah... Hello =) didn't know this, now things make more sense :D

Have found the chart i was talking about. It was not about pressure but about the mammoth engines thrust.
S7xD9DN.png

It's around 8% loss at launch.
I did not expect that the better workings wings can compensate this that well. But obviousley they do verry well :o

I should have realized this, wehen @astrobonddid build the smalles Eve SSTO i have seen so far. It's also a plane, and it Shows how small wings can be now
https://www.youtube.com/watch?v=8Q-PJ4FgWpg&t=34s

 

So Maybe you can even scale yours down now in 1.2+?

 

If i ever find the time for Eve SSTOs again, I will definitely also try planes again :D

 

PS: did you know about this? Was a little frustrating seeing this. :D But great work anyway and thanks for the mention (I think you meant my SSTO?) :)

 

 

Hi @Kergarin :)  The big difference with wings is that you can takeoff with a smaller than 1 twr... That's why i choose that ! as you can see, the twr of my "little" Eve SSTO is 0.86 at takeoff...

Share this post


Link to post
Share on other sites
1 hour ago, astrobond said:

Hi @Kergarin :)  The big difference with wings is that you can takeoff with a smaller than 1 twr... That's why i choose that ! as you can see, the twr of my "little" Eve SSTO is 0.86 at takeoff...

Hi @astrobond :) so this turns into a Eve SSTO expert meeting, it seems :D

Did you also experience wings working better on eve in 1.2 and above, or how were you able to scale it down that much compared to your old one?

Share this post


Link to post
Share on other sites
8 minutes ago, Kergarin said:

Hi @astrobond :) so this turns into a Eve SSTO expert meeting, it seems :D

Did you also experience wings working better on eve in 1.2 and above, or how were you able to scale it down that much compared to your old one?

LOL yesss ;)

I don't remember exactly, but after 1.04, i was unable to SSTO Eve with my old ship... but when i tried again in 1.3, that was ok !

So i tried to scale down because the "vector" engine is exactly the same isp as the "mammoth", and because i wanted to try something new ;)

BTW the weight is 4 tons for 1000 Kn on the "Vector", vs 15 tons for 4000 Kn for the "Mammoth', so on the paper the Vector is not so good... but in fact in 1.3, even if that's still very hard to SSTO Eve, i'm sure this is easier than in 1.04 !

The key is also to have the less possible drag, and the "Strake" wings seems to be very good for lift/drag ratio :)

My two cents...

 

Share this post


Link to post
Share on other sites
4 hours ago, astrobond said:

LOL yesss ;)

I don't remember exactly, but after 1.04, i was unable to SSTO Eve with my old ship... but when i tried again in 1.3, that was ok !

So i tried to scale down because the "vector" engine is exactly the same isp as the "mammoth", and because i wanted to try something new ;)

BTW the weight is 4 tons for 1000 Kn on the "Vector", vs 15 tons for 4000 Kn for the "Mammoth', so on the paper the Vector is not so good... but in fact in 1.3, even if that's still very hard to SSTO Eve, i'm sure this is easier than in 1.04 !

The key is also to have the less possible drag, and the "Strake" wings seems to be very good for lift/drag ratio :)

My two cents...

 

I just did some tests. :D Wings really work much bette now. At 7500 a verry low speed is enough to get airborne.

Maybe it can be scaled to a point where it can also reenter and land? A few more strakes are enough to survive reentry. But that's already to much extra weight to reach orbit.

  • Like 1

Share this post


Link to post
Share on other sites

The following is not a SSTO from Eve surface. I'm not sure why one would even want one as the margins are to tight. I've seen youtube videos of people that already made Eve ssto's. Although I'm not sure if they cheated.

Anyway, I always thought of a TSTO system for Eve that would start at the lowest part of eve's highest peak on the equator (you know where)
Then accelerate with a second stage it carries up to 7km near the top of the mountain with decent speed (300-400m/s, MOAR) and then decoupler the second stage.

But as you do that you use a action group that opens many chutes and airbrakes and retro thrusters to quikcly deccelerate before the 1st stage reaches the peak while the second stage flies onwards. The same action group also lowers a array of landing gear with which the 1st stage is covered with with max friction and brake settings.

With the correct timing the 1st stage should auto land near or at the top of the mountain before the 2nd stage gets out of physics range. Then you switch back to the 2nd stage and get to orbit. With a efficient 2nd stage you should even be able to carry actual cargo from Eve this way.

After orbit you land the 2nd stage near the peak and fly the first stage from the mountain top back to sea level. Of course you need a system to put the 1st stage upright if it landed on its side or worse, upside down.
It or another vessel near the bottom of the peak would have a ISRU, and the 1st stage would have a Sr docking port mechanism to dock with the 2nd stage again so both stages can refuel and repeat the process for a fully reusable Eve cargo hauler.

If there is a flaw in this KSP dream then don't hesitate to take me out of it. I only thought of it recently and maybe I'll try this for myself soon.

 

Share this post


Link to post
Share on other sites
Posted (edited)
36 minutes ago, Aeroboi said:

The following is not a SSTO from Eve surface. I'm not sure why one would even want one as the margins are to tight. I've seen youtube videos of people that already made Eve ssto's. Although I'm not sure if they cheated.

Anyway, I always thought of a TSTO system for Eve that would start at the lowest part of eve's highest peak on the equator (you know where)
Then accelerate with a second stage it carries up to 7km near the top of the mountain with decent speed (300-400m/s, MOAR) and then decoupler the second stage.

...

If there is a flaw in this KSP dream then don't hesitate to take me out of it. I only thought of it recently and maybe I'll try this for myself soon.

 

As I can say some did not cheat :wink:

300-400m/s in Eves low atmosphere already create heavy forces. Any sudden movement can destroy a craft easily, and I think it's also way to fast to open a chute. On the other hand, if you are at 300-400m/s you have probably not reached a height where more efficient engines start to work. This is just guessing based on my experiences, you are free to prove me wrong :wink:

But I think it is easier, to build a first stage which can push the second stage out of the atmosphere, and have a second stage which circularizes its orbit quickly, before the first stage re enters the atmosphere.

Something like this has already been done: 

It's an interesting way, but I don't know if this is much easier than a low margin self refuelling SSTO

 

 

Edited by Kergarin
  • Like 2

Share this post


Link to post
Share on other sites
13 minutes ago, Kergarin said:

As I can say some did not cheat :wink:

300-400m/s in Eves low atmosphere already create heavy forces. Any sudden movement can destroy a craft easily, and I think it's also way to fast to open a chute. On the other hand, if you are at 300-400m/s you have probably not reached a height where more efficient engines start to work. This is just guessing based on my experiences, you are free to prove me wrong :wink:

But I think it is easier, to build a first stage which can push the second stage out of the atmosphere, and have a second stage which circularizes its orbit quickly, before the first stage re enters the atmosphere.

Something like this has already been done: 

It's an interesting way, but I don't know if this is much easier than a low margin self refuelling SSTO

 

 

Well, it's no time to prove it yet :P

But you can make vessels very aerodynamic to the point where they can maintain 300-400m/s at a altitude of 7000-8000m on Eve. Think about using optimized fairing shape, vector engines (which aren't very draggy) and wing incidence. On eve I think vaccuum optimized engines would work out better on a TSTO since they already work somewhat better at 8000m and with 400m/s speed you wont be penalized with the ISP reduction to long as you will be above 12.5km pretty quickly and there above where ISP starts to climb above Kerbin sea level.

You are definitely right about the chutes that would be ripped off. I was just summarizing options. One of the options was retro thrusters. I imagine some well forward placed vector engines can quickly arrest a vessels forward motion. If you tweak the amount of fuel it is feeded with you should be able to calculate how much is required to propulsively brake the 1st stage in time so that it's near the top. If required open the chutes after the propulsive braking and then quickly switch back to the 2nd stage.

If you do it right chutes wont be needed at all as the landing gear should be able to absorb the impact if you use enough of them.

And your talking about Stratzenblitz design which is awesome. I would want to go further or see someone else try to find a way to lift something meaningful of off Eve but it's a challenge I and everyone still have to win.

But I don't want to derail the topic because the challenge is clearly SSTO and not TSTO. I just wanted to share what sort of recoverable lifter design I would want to see arise from these Eve SSTO or general eve lifter suggestions/challenges.

Share this post


Link to post
Share on other sites
45 minutes ago, Aeroboi said:

Well, it's no time to prove it yet :P

...

But I don't want to derail the topic because the challenge is clearly SSTO and not TSTO. I just wanted to share what sort of recoverable lifter design I would want to see arise from these Eve SSTO or general eve lifter suggestions/challenges.

Hope you will find the time and share your results :)

Share this post


Link to post
Share on other sites
On 10/6/2018 at 12:28 PM, EvermoreAlpaca said:

  I originally built the craft before 1.2, but the changes in that patch improved performance.

I looked back at the change log, and see that was when they made blunt things drag more above Mach-1 pointy things drag less. That was a noticeable change, making it pay more to streamline.

But then the asteroid-grabbing space-plane we were talking about is the one with the boldly-flat nose.  You might have stumbled into an exploit, if you node-attached the asteroid-grabber onto the nose, then offset it into the cargo bay.  The basic drag model removes drag from a surface if it is covered by an attached part, since the attached part will block the airflow, but then a second system removes drag from parts shielded in a bay.  You can eliminate the drag of the nose that way.  Some players raise this to an art form.

Share this post


Link to post
Share on other sites
On 10/13/2018 at 5:24 PM, OHara said:

I looked back at the change log, and see that was when they made blunt things drag more above Mach-1 pointy things drag less. That was a noticeable change, making it pay more to streamline.

But then the asteroid-grabbing space-plane we were talking about is the one with the boldly-flat nose.  You might have stumbled into an exploit, if you node-attached the asteroid-grabber onto the nose, then offset it into the cargo bay.  The basic drag model removes drag from a surface if it is covered by an attached part, since the attached part will block the airflow, but then a second system removes drag from parts shielded in a bay.  You can eliminate the drag of the nose that way.  Some players raise this to an art form.

It used the rather old trick of the reverse nose cone.  The asteroid grabber is mounted inside the utility bay.  Fairing aerodynamics more or less obsolete the need for the nosecone trick nowadays.

Share this post


Link to post
Share on other sites

That makes sense.  The hidden rotated nose-cones cover the flat ends of the mk2 fuel tanks, leaving them with the nice low Cd=0.08 that versions 1.2+ favor.  Then KSP applies the (correctly) much lower tail-drag rather than leading-edge drag to the cone part of the nosecones, but doesn't notice that the leading edge is now a flat plate (incorrectly).

The sharp pointy fairing on Aerobond's SSTO (linked earlier in the thread) has a pretty low Cd=0.16, and the recent aerodynamics model does give that low supersonic drag.
Sharp fairings give less advantage than rotating a nose (2.8× drag at Mach 1 from physics.cfg) to a tail (0.22× drag at Mach 1) but the sharp fairing method uses the aspects of aerodynamics that KSP gets right.

 

 

Edited by OHara

Share this post


Link to post
Share on other sites

slow claps

shower of praise

Share this post


Link to post
Share on other sites
7 hours ago, EvermoreAlpaca said:

I thought this was impossible, but have proven myself wrong: 

 

WOW !!! Congrat's @EvermoreAlpaca well done :)

Share this post


Link to post
Share on other sites
18 hours ago, EvermoreAlpaca said:

I thought this was impossible, but have proven myself wrong

Holy moly, that's amazing! :o

@EvermoreAlpaca I tip my hat to you sir

Edited by ManEatingApe
Language

Share this post


Link to post
Share on other sites
16 hours ago, EvermoreAlpaca said:

I thought this was impossible, but have proven myself wrong: 

 

Congratulations! You have done the impossible :o

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now