Lightest Eve Lander Challenge v1.1.x & v1.2.x

[Foxster]

Yup, I remember your post about that before. I had a go at reproducing it and I struggled but can see how it might work that way. One thing might be about making sure you make the tail of each stack aerodynamic too. 

[foamyesque]

Hm, you know, I should try my last Eve lander design out in the new version, which has had some changes to aero and heating. It isn't especially light, but it is quite capable and only needs to stage away a single engine on Eve :v

[tseitsei89]

http://imgur.com/a/lhYBN

Recently did this for my Lightest Eve lander in 1.2. challenge but this one seems to be more active so I'll post it here too.

Can do re-entry and get back to orbit and weighs less than 30t

Ascent profile can be seen here:

https://www.youtube.com/watch?v=onABiPxvs-o&feature=youtu.be

[Foxster]

6 hours ago, tseitsei89 said:

http://imgur.com/a/lhYBN

Recently did this for my Lightest Eve lander in 1.2. challenge but this one seems to be more active so I'll post it here too.

Can do re-entry and get back to orbit and weighs less than 30t

Ascent profile can be seen here:

https://www.youtube.com/watch?v=onABiPxvs-o&feature=youtu.be

I tried again last night with your craft and I still can't make orbit with it. Sucks to be me. 

[Redshift OTF]

9 hours ago, tseitsei89 said:

http://imgur.com/a/lhYBN

Recently did this for my Lightest Eve lander in 1.2. challenge but this one seems to be more active so I'll post it here too.

Can do re-entry and get back to orbit and weighs less than 30t

Ascent profile can be seen here:

https://www.youtube.com/watch?v=onABiPxvs-o&feature=youtu.be

Wow, the new leader! This is most impressive and kind of looks like the one I have been working on, (but haven't had time to test yet):

BTW, I count the weight after the landing gear, parachutes etc have been jettisoned but before the engines have fired. If you remove these items in the VAB, (obviously you still need them to land with), then this is the weight of the Eve lander making yours even lighter! Do you have a craft file?

Great job and I will have to see if it is beatable.

[tseitsei89]

20 hours ago, Foxster said:

I tried again last night with your craft and I still can't make orbit with it. Sucks to be me. 

That's weird since I know that you are actually quite good at this game... And I have now tested this design on 2 different computers and fresh install and it works on all of them.

18 hours ago, Redshift OTF said:

Wow, the new leader! This is most impressive and kind of looks like the one I have been working on, (but haven't had time to test yet):

BTW, I count the weight after the landing gear, parachutes etc have been jettisoned but before the engines have fired. If you remove these items in the VAB, (obviously you still need them to land with), then this is the weight of the Eve lander making yours even lighter! Do you have a craft file?

Great job and I will have to see if it is beatable.

I don't have the craft file anymore because I changed computer after that. But quick calculation gives us 0.025*12 (radial decouplers) +0.1*8 (landing struts) +0.1*8 (parachutes) +0.05 (decoupler for the heatshield) +1.5 (heatshield) = 3.45t

Which gives us a total mass of 29.96-3.45=26.51t with everything needed for landing removed

[Foxster]

3 minutes ago, tseitsei89 said:

That's weird since I know that you are actually quite good at this game... And I have now tested this design on 2 different computers and fresh install and it works on all of them.

Maybe you could re-create it and post the craft file? 

It looks pretty simple to reproduce from the pictures, assuming there is nothing clipped away, and the flight profile seems to be nothing too fancy. I just always come up at least a few hundred dV short. 

I do know that there is definately some dV saving to be made compared to the last KSP release because my other Eve craft can now be flown so they have a lot of dV left by orbit but I can't get the total dV down to the <6KdV you achieved. 

[Redshift OTF]

Ah, I have noticed a slight issue. Category 2 requires that you take off from an altitude of 100m or less and it looks like your ship is taking off from around 600-900m in both examples. That extra height makes quite a difference and I don't think your vessel is going to make it from under 100m. Quite an achievement though but it only satisfies Category 1 I'm afraid.

[Firemetal]

On ‎12‎/‎9‎/‎2016 at 4:40 AM, tseitsei89 said:

http://imgur.com/a/lhYBN

Recently did this for my Lightest Eve lander in 1.2. challenge but this one seems to be more active so I'll post it here too.

Can do re-entry and get back to orbit and weighs less than 30t

Ascent profile can be seen here:

https://www.youtube.com/watch?v=onABiPxvs-o&feature=youtu.be

Hey! You used the gravity turn trick I found out recently.  Awesome!

Fire

[tseitsei89]

6 hours ago, Foxster said:

Maybe you could re-create it and post the craft file? 

It looks pretty simple to reproduce from the pictures, assuming there is nothing clipped away, and the flight profile seems to be nothing too fancy. I just always come up at least a few hundred dV short. 

I do know that there is definately some dV saving to be made compared to the last KSP release because my other Eve craft can now be flown so they have a lot of dV left by orbit but I can't get the total dV down to the <6KdV you achieved. 

https://www.dropbox.com/s/1g9j2jn7e65t987/eve lander.craft?dl=0

There you go. And yes nothing is clipped inside anything.

6 hours ago, Redshift OTF said:

Ah, I have noticed a slight issue. Category 2 requires that you take off from an altitude of 100m or less and it looks like your ship is taking off from around 600-900m in both examples. That extra height makes quite a difference and I don't think your vessel is going to make it from under 100m. Quite an achievement though but it only satisfies Category 1 I'm afraid.

http://imgur.com/a/tNwpy

That's my best attempt this far from <100m starting elevation. Frustrating 29m/s short off orbit   but I'll keep trying. I believe it's possible with good enough ascent profile...

Edited December 10, 2016 by tseitsei89

[EvermoreAlpaca]

The return craft from my Eve deep sea mission was in the 5-6 ton range.  I used a command seat because that's how I roll, but one could redesign using the same concept and still have a very light design. 

https://m.youtube.com/watch?v=Tk73lZTwR6c#

Ascent is around 8 minutes,  I'm too noob to link from time on my phone. 

Edited December 10, 2016 by EvermoreAlpaca

[tseitsei89]

http://imgur.com/a/Pk4TF

LOL 8m/s short off stable orbit...

[tseitsei89]

26 minutes ago, EvermoreAlpaca said:

The return craft from my Eve deep sea mission was in the 5-6 ton range.  I used a command seat because that's how I roll, but one could redesign using the same concept and still have a very light design. 

https://m.youtube.com/watch?v=Tk73lZTwR6c#

Ascent is around 8 minutes,  I'm too noob to link from time on my phone. 

 nice craft I played with the same idea once and build some helicopter thingies to fly around KSC. Reaction wheels are lol OP  

[Foxster]

Here's a 33.2t craft of mine that can comfortably do the mission from 92m. It can do it very easily with no special flying, it has dV to spare and can even be flown to orbit with MJ...

Mission pictures: https://imgur.com/a/nTKgd

[tseitsei89]

Sorry for the triple post but I DID IT!

The ascent profile has to be VERY accurate this time in order to succeed. Keep twr between 1.7 and 2 until you start gravity turn at around 5.5km. Then after the 2nd stage separation keep twr at little over 1 until you are tilted little less than 45 degrees from vertical. Then full throttle and keep burning until ap >90km. Circularize.

 

http://imgur.com/a/Hos1b

Picture of the craft in VAB with all accessories needed for deorbit, re-entry and landing (29.08t) AND also picture of the craft without any of those if you would rather use those masses (26.31t).

Edited December 10, 2016 by tseitsei89

[Redshift OTF]

Awesome work there guys! 26.31 tons, that's definitely a record there. I guess the key is to ascend slowly at first and then put the craft on full power to give the top stage enough momentum to get out of the atmosphere quickly enough for the Terrier engine to do its job. I like Foxsters version of replacing the Terrier with Spark engines. I might go that route with my craft as I don't seem to be having much luck at the moment. I was also under the impression that the shock nose cones were the least draggy part to cap the end of side pods but you guys seem to be having better luck with other components. I'll have to do more research!

Anyway, great stuff. Can these be beaten?

[tseitsei89]

2 hours ago, Redshift OTF said:

Awesome work there guys! 26.31 tons, that's definitely a record there. I guess the key is to ascend slowly at first and then put the craft on full power to give the top stage enough momentum to get out of the atmosphere quickly enough for the Terrier engine to do its job. I like Foxsters version of replacing the Terrier with Spark engines. I might go that route with my craft as I don't seem to be having much luck at the moment. I was also under the impression that the shock nose cones were the least draggy part to cap the end of side pods but you guys seem to be having better luck with other components. I'll have to do more research!

Anyway, great stuff. Can these be beaten?

Thanks! And yes I guess that is the best way to do it but Eve's atmosphere has definitely changed a lot because now I can start a gravity turn at ~5.5km instead of something like 10+km in the past. And that obviously leads to lighter landers.

As for the Foxsters 3 spark idea. It has a point since 3 sparks give as much thrust as 1 terrier but weigh 0.2t less. Although I have yet to figure if it's worth it or not since sparks also have a slightly lower ISP and they also add some drag since they have to be mounted radially.

And as for the drag of parts I have no idea what is really the least draggy part since I only ran a quick and simple test. What I did was that I just tried a same craft with different parts as a nose cone and flew straight up until out of fuel and picked the part that got me the highest ap. Some parts can have more/less drag in higher/lower speeds tough so I don't really know what's optimal part for the job. I guess you could figure it out directly from the part files somehow but I don't really like that kind of an approach...

[Foxster]

Shockcones were king before 1.2 (was it then?) but then their mass went up a lot. You used to have to worry a lot about heatplosion of the nosecones too but that is less a worry now, so it is generally OK to use whatever is lowest drag+mass now. 

There's a good reason I use the 3 Sparks but it is not necessarily relevant to this craft. They can be run from launch along with the other engines because of their positioning and their isp. So, if you have a low TWR (e.g. aerospike) craft then they can add a little extra umph that can make all the difference. 

Kudos to tseitsei89 for being one of the first to figure out how to make use of the recent atmos changes on Eve. I still haven't managed to get his craft to orbit! Not that I doubt at all that it can be done, it is just so marginal that it takes some fine flying to make it happen. I  prefer my craft to have a little more margin and repeatability . 

[Foxster]

Another little go from me at 24.928t.

Hopefully we can assume I could land this OK as that would be just the same as the other attempts. 

Album: https://imgur.com/a/v50x4

Edited December 11, 2016 by Foxster

[tseitsei89]

2 hours ago, Foxster said:

Another little go from me at 24.928t.

Hopefully we can assume I could land this OK as that would be just the same as the other attempts. 

Album: https://imgur.com/a/v50x4

Nice idea to reduce drag by using smaller radius tanks. Also maybe lander can could be better now than the actual re-entry pod since the drag is slower. Let's see what I can do with this...

[tseitsei89]

http://imgur.com/a/w3Q64 picture from VAB 22.865t

Video of the ascent.

 

[Firemetal]

Ok I have been playing around with 50> ton landers.

Here is what I got for category 1.

Spoiler

Lander info:

Lander mass: 41.325 tons.

Lander DV: Around 7km/s of DV.

Lander launch TWR: 1.31

Lander takeoff altitude from sea level: 2151m

Orbit achieved: 185x121km.

Sorry for lack of screenshots, was focusing on the launch. Also while take off, had a hard time getting to go up due to a low TWR and being on a hill but did it eventually. I'm pretty sure this lander can take off and reach orbit from lower altitudes but this requires a much lower orbit to get into, a flatter area to take off in so I don't waste so much fuel on takeoff and a more efficient flight path but that will require more testing.

That's it for now.

Fire.

Edit: Tried again at 1444m up and still got into orbit with fuel to spare. Still had trouble with takeoff and I'm assuming it is that my TWR isn't high enough so with Eve lander 6.1, I'm adding 2 aerospikes to help with takeoff. Hopefully that works.

Edited December 12, 2016 by Firemetal

[Redshift OTF]

Impressive entries as always here! I'm liking the use of thinner parts to reduce drag. If anyone feels they have reached the limit with their landers please feel free to try category 0, forgoing the use of a command pod and using a chair in a service bay for your Kerbal. Still under 100m. I would be interested to see how low a sea-level lander can go!

To make it easier to get vessels to Eve's surface I am using a combination of the in-built cheat menu to put crafts in orbit above Eve, using Hyper-edit to land them and then placing Vessel Mover to pick them up and place craft somewhere below 100m. Or if you have Hyper-edit you can use the following co-ordinates for a nice flat area near sea-level:

[Redshift OTF]

Finally got my lander into orbit!

It's not as light as some of the competition but I'm proud of 30.565 tons. It also uses MechJeb with the following settings, although I am running the mod that allows me to have MechJeb on a craft without adding the part as it generates a fair bit of drag in the final stage, (which might have killed some of my other designs). No doubt if I learned how to pilot manually it would have a fair amount of DeltaV left over in orbit. Only uses 5 Aerospikes and 2 Spark engines.

Craft file if anyone wants it:

https://drive.google.com/open?id=0B9mK0rPybNaxRW1RSnJTc0c5WG8

Edited December 12, 2016 by Redshift OTF

[Foxster]

Nice job!

A couple of thoughts if I may...

Those big radial decouplers are very draggy. Small hardpoints much less so. 

You don't need the fuel ducts with KSP 1.2's fuel priority functionality and if you use the latest MJ (released today) it will calculate the dV OK without them. Remember to enable crossfeed on the radial decouplers though. 

If you use a little more fuel in the last stage with 3 Sparks then you will need less engine/fuel in the lower stages. 

You did remember to take the RCS fuel out of the capsule?

Not sure if it would be an issue for that craft because the TWR of the later stages is fairly low but you might want to think about limiting Q to, say, 220000 and/or limiting the angle of attack to 5°.