So what does it take to get off of Eve these days?

[magnemoe]

My Eve launcher uses an light pod from an mod with an advanced nosecone on top, mechjeb launch who don't start to turn before 30 km, nosecone explodes at 50 km, luckily this is too high to heat the pod much
 

[Firemetal]

Been testing with Eve landers with hype reedit.  First they must survive re-entry. You If I lose control during Re-entry, it's all over. Then it lands. Then it must get back to orbit. I built 7 landers and none of them worked.

So I built the eighth one and this had 4600 m/s at sea level. I screwed up the ascent and didn't make it but then I tried again and landed on a 3000m high slope. I got back to orbit with 1000m/s left.

The ultimate Eve lander!

http://imgur.com/a/gCBZ2

(all Dv readings were atmospheric by the way)

Edited July 29, 2016 by Firemetal

[Foxster]

Nice job!

A few thoughts on your craft if I may...

What are all the batteries for? They are adding a lot of unnecessary weight. Same with all the big reaction wheels. One at most should do it. 

Using the one big inflatable heat shield will likely be better than all the small ones. 

That outside set of tanks will be very draggy, swap out for mk1 sized tanks if they are involved with the ascent at all.

Mount your chutes so that they can all be dumped before lifting off again to save mass. 

Using the mk1 capsule (with RCS removed) will be more efficient than the lander-can because of the reduced drag, even though it is slightly heavier. 

Get rid of as many struts as you can, they are very draggy and heavy. 

You seem to have a used fairing on there that you are carting about. Find a way to get rid of it. 

Find a way to get your central stack down to mk1 size to reduce drag further. 

 

[gilflo]

 

[purpleivan]

I launched the less than svelte Eve Redux (minus the guide fins at the top and the parachute packs) a few weeks ago from 1100m and it provided some 5200 dV at sea level (9800 vacuum)

It wasn't particularly aerodynamic and I tumbled twice in the ascent forcing me to cut the engines each time, once between 27 and 29km and again between 60 and 85km (managed to get a few squirts of thrust during this one though). The final orbit was at 120km

Edited July 30, 2016 by purpleivan

[ZentroCatson]

I tried to build an Eve lander myself, but I came across a big problem. On descent, my lander flips head-first into the atmosphere and explodes due to overheating because of that inflatable heat shield at its back. I know why it does this, but how do you guys counter this sort of behavior? I've tried tail fins and aerobrakes, but it doesn't help. 

[Foxster]

1 hour ago, ZentroCatson said:

I tried to build an Eve lander myself, but I came across a big problem. On descent, my lander flips head-first into the atmosphere and explodes due to overheating because of that inflatable heat shield at its back. I know why it does this, but how do you guys counter this sort of behavior? I've tried tail fins and aerobrakes, but it doesn't help. 

Couple of things...

Get the CoM lower down towards the heatshield. Not easy as it requires some re-design. 

Add more air brakes at the top. You might need a lot but you should make them disposable once you are landed to eliminate the mass before lifting. 

[Firemetal]

On July 29, 2016 at 9:05 AM, Foxster said:

Nice job!

A few thoughts on your craft if I may...

What are all the batteries for? They are adding a lot of unnecessary weight. Same with all the big reaction wheels. One at most should do it. 

Using the one big inflatable heat shield will likely be better than all the small ones. 

That outside set of tanks will be very draggy, swap out for mk1 sized tanks if they are involved with the ascent at all.

Mount your chutes so that they can all be dumped before lifting off again to save mass. 

Using the mk1 capsule (with RCS removed) will be more efficient than the lander-can because of the reduced drag, even though it is slightly heavier. 

Get rid of as many struts as you can, they are very draggy and heavy. 

You seem to have a used fairing on there that you are carting about. Find a way to get rid of it. 

Find a way to get your central stack down to mk1 size to reduce drag further. 

 

Reaction wheels and batteries, ok. Everything else would most likely ruin the design. It can just barely reach orbit the way it is now. Also the 10m heat shield cannot shield whole thing itself. It needs the smaller ones too.

Thanks for the suggestions though! They were very helpful.

[gilflo]

7 hours ago, ZentroCatson said:

I tried to build an Eve lander myself, but I came across a big problem. On descent, my lander flips head-first into the atmosphere and explodes due to overheating because of that inflatable heat shield at its back. I know why it does this, but how do you guys counter this sort of behavior? I've tried tail fins and aerobrakes, but it doesn't help. 

Take a look at my previous post and look on my screen how i dealt with it:

-Set at the top of your lander an ejectable device with:

 +a small tank for RSC vernor engines

 +6 or 8 speed brakes that you will leave open during all descent to help stabilize the whole ship

-Set well dimensioned ejectable vernor engines (tweaked if necessary or doubled or triple set) on the COM of the whole ship-including the top device (all around your lander tank) to help keeping retrograde on descent if necessary

-Eject the top device when heating is no more a factor and you are near vertical descent (around 20 kms) - Eject vernors or keep it and eject before take off

-Open chutes at 10kms and when they open fully at 700m above ground, eject the shield. it will descent quicker than your lander.

[ZentroCatson]

7 hours ago, Foxster said:

Couple of things...

Get the CoM lower down towards the heatshield. Not easy as it requires some re-design. 

Add more air brakes at the top. You might need a lot but you should make them disposable once you are landed to eliminate the mass before lifting. 

Thanks for the answer, that was exactly what I needed! I tried both lowering the CoM and adding more air brakes, and it did help! Now I only have to design a lander that can successfully ascent from sea level AND be stable on descent…

1 hour ago, gilflo said:

Take a look at my previous post and look on my screen how i dealt with it:

-Set at the top of your lander an ejectable device with:

 +a small tank for RSC vernor engines

 +6 or 8 speed brakes that you will leave open during all descent to help stabilize the whole ship

-Set well dimensioned ejectable vernor engines (tweaked if necessary or doubled or triple set) on the COM of the whole ship-including the top device (all around your lander tank) to help keeping retrograde on descent if necessary

-Eject the top device when heating is no more a factor and you are near vertical descent (around 20 kms) - Eject vernors or keep it and eject before take off

-Open chutes at 10kms and when they open fully at 700m above ground, eject the shield. it will descent quicker than your lander.

A top device is a good idea, but will possibly hurt the aerodynamics while launching the lander from Kerbin. Having Vernors is also quite smart, I'll try that if @Foxster's CoM lowering methode won't work. And I already know about the last point, my avatar may be a cow, but I'm definitely smarter than a cow 

Edited July 31, 2016 by ZentroCatson
Nothing to see here…

[foamyesque]

Just send a plane. It's the best way to get back off, too, since it allows you to use a much lower TWR. Dude managed to SSTO off the mountaintops with one.

[Foxster]

7 minutes ago, foamyesque said:

Just send a plane. It's the best way to get back off, too, since it allows you to use a much lower TWR. Dude managed to SSTO off the mountaintops with one.

Umm, not so sure about this. That SSTO was very marginal too. 

[foamyesque]

1 minute ago, Foxster said:

Umm, not so sure about this. That SSTO was very marginal too. 

Sure, it was marginal; it's Eve. I use a three-stage escape vehicle for ASL exits, the first stage of which is nothing more than an enormous winged pair of drop tanks, whose only purpose is to lift the next two stages to a functional altitude where they can operate with TWR > 2 and less of a molassesphere to plough through. Wings are also a great way to slow down a heavy-duty Eve lander, though getting the control and balance right on them is tricky.

[Foxster]

Have some pictures of the aircraft?

[foamyesque]

1 hour ago, Foxster said:

Have some pictures of the aircraft?

 

Not many; I'm currently flying the actual mission, and don't generally bother with screenshots of my (HyperEdit assisted) test flights. However:

 

 

The boosters SSTO the stack and are winged for recovery; then, I refuel at Minmus (which is really tight on the deltaV budget; my actual-mission landing there touched down with 4m/s left) via a ventral-vernor RCS touchdown and integral ISRU unit, then head to Eve from there. Orbital manouvering, (i.e. insertion and circularization) burns off almost all of the remaining fuel, and a refuelling drone is dropped off for later. Then, execute a near-bingo entry, and refuel on Eve for the return flight. The drop tanks feed the remaining Mammoth as they loft the ship up to about 7-8km altitude (and I drop the ISRU unit out of its housing); near the end of the climb, in the last ten seconds or so, since the tanks are nearly empty and the Mammoth's Isp considerably improved, the Eve TWR climbs to well above 1 and I execute a pitch up to put my nose (almost) vertical, then drop the tanks and their wings and climb on the core tankage, which carries large wings to counteract the effects of the Kerbin lander atop it. I need to throttle back a little as it gets into the upper atmosphere since it can drive the ship fast enough for heating explosions, but it gets me to 75km or so and a solid velocity; the Poodle on the upper stage then suffices to achieve orbit around Eve. At that point, the refuelling drone docks with it, and provides adequate deltaV for a return-to-Kerbin manouver, whereupon the winged upper section performs a standard shuttle-style entry and landing.

 

 

[gilflo]

16 hours ago, ZentroCatson said:

A top device is a good idea, but will possibly hurt the aerodynamics while launching the lander from Kerbin. Having Vernors is also quite smart, I'll try that if @Foxster's CoM lowering methode won't work. And I already know about the last point, my avatar may be a cow, but I'm definitely smarter than a cow 

Use a fairing for launch and eject when you are over 20kms when air resistance is no more a factor

[ZentroCatson]

3 minutes ago, gilflo said:

Use a fairing for launch and eject when you are over 20kms when air resistance is no more a factor

An upside down fairing, to be precise. And I only eject the fairing once on the surface of Eve, together with the rest of the top device since my lander is supposed to be launched and landed uncrewed and only be crewed once on the surface of Eve.

Edited August 1, 2016 by ZentroCatson

[kurdain]

This might be the wrong place to ask but I am having an issue with getting off of Eve. I used to do it in the past, things have changed since I last played and I am playing this time with A LOT of mods, it's been fun.

However it seems Eve is made of velcro. Unless I use SRB's I can't get off of the ground, this only happens on Eve.

If I get even 50 meters off the ground my LFO rockets lift the craft just fine, I've ensured I've had over a 1.7:1 TWR according to mechjeb. It's gotten so bad I am using Hyperedit to try craft as apparently I am getting 'stuck' in the ground and waiting hours for a seemingly bugged failed Eve return is frustrating.

Is mechjeb returning VERY wrong results?

Is there a known mod to cause 'sticky' ground or are modded rockets like cryoengines reporting very wrong TWR on Eve? (which seems weird because as soon as I get off the ground I can ignite them and accelerate just fine).

I built a stock lander and it appeared stuck too, put a small SRB on it and again as soon as I got a few meters off the ground the LFO's (the early 1.25m one that has good gimbaling - at work can't recall the name) were able to take it up. I then tried again and left it on the ground, full throttle, until all the fuel was spent, ended with over 2.5:1 TWR towards the end and the lander never budged.

 

if this is the wrong spot please move this post but the thoughts here seemed relevant.

 

Thanks,