Laythe lander , need help

[bjerrang]

So my first laythe lander failed bigtime.

3 spark vac engines and 1 terrier 3600dV in vac , barly came up to 35000 meters.

I know this is a engine issue , and i can just swap it for a reliant/swivel engine.

But is the lander better to be a spaceship or just i just fumble with the rapier engine?

A photo of laythe lander you use would be great. 

I need a simple craft for 1 person to land collect science and dock with space station in orbit.

Edited February 20, 2018 by bjerrang

[Foxster]

Can you post a piccie of your craft?

[bjerrang]

5 hours ago, Foxster said:

Can you post a piccie of your craft?

Ofc , i reverted the landing. Removed most of the fuel and just landed it as a Science project. 

[Guest]

Craft files available here: https://kerbalx.com/hangars/29774

 

[Spricigo]

In before the move to spacecraft exchange.

This thread need more wingless jet-powered craft. 

[bjerrang]

9 hours ago, Brikoleur said:

 

 

 

Craft files available here: https://kerbalx.com/hangars/29774

 

That is way off what i need. But cool craft!

Edited February 20, 2018 by bjerrang

[Guest]

Laythe is made for planes, is all I'm saying. A conventional lander like you'd make for a vacuum/thin atmosphere world won't work. If you don't want to make a plane, you'll need to streamline yours at least, otherwise it won't make it back up as it'll burn all its fuel fighting drag. For a Laythe rocket, you'll want parachutes on the way down; you won't need to burn retrograde much if at all, perhaps a little puff at the end. The difficulty will be getting back up: you'll want engines with good atmospheric performance and sufficient TWR to get on a nice ballistic trajectory.

RAPIERs won't help for a ballistic launch. You'll be going too steep for them to have time to build up serious thrust, and you'll need to pile on way too many to get going in the first place. I've tried, no dice. Rockets are better for ballistics.

Think of Laythe as Kerbin lite. Gravity is a bit lower and the atmosphere is a bit thinner, which means everything will be a little easier. Make a Kerbin lander. If it barely works on Kerbin, it'll work excellently on Laythe. 

[Aegolius13]

A couple thoughts.  First, that lander is pretty draggy.  Laythe's atmosphere is not too much thinner than Kerbin's ,so drag matters and your design should ideally look closer to a Kerbin rocket.  Maybe look at the command pod instead of lander can, avoid changing part width, and put some nosecones on the radially-mounted nacelles.  Think about putting your science equipment in a service bay; see if you can get by without RCS thrusters, etc. 

Second, the engine setup.  A couple folks have mentioned jets, which work great on Laythe.  But if you want to stick to rockets, I'd make a few tweaks.  If I understand this right, you use the Sparks to start, and switch to the Terrier when the atmosphere thins out?  I'm not sure the extra mass of the Terrier is worth the small ISP gain in that situation.  You might want to see how it goes with just the Sparks.  

You might want to look at the Aerospike,  which would have good ISP and thrust throughout the trip.  But it would add mass relative to what you have now, and you'd need something else (fins, or Spiders, or something) for attitude control.  So you might need to add a little fuel as well to extend range. 

[Vanamonde]

Craft sharing thread moved to the craft sharing subforum. 

[Aegolius13]

Here is a quick design along the lines of what I mentioned above.  Aerospike on the bottom center.  This will SSTO from sea level.  I did not put the add the full suite of science equipment, parachutes, etc, but I finished with a decent amount of d/v left so I think it could handle it. 

I did notice that this design produced a fair amount of drag as well, especially the docking port on the very front.  This exacerbated on Laythe since the atmo stays fairly thick as you ascend.  I tried a relatively steep climb to deal with this.  

If you were to keep the Sparks on the nacelles and ditch the central Terrier, you could even think about putting the docking port on the BOTTOM of the core, and sticking a nosecone on the top.  That would improve the aerodynamics noticeably. 

 

[Zosma Procyon]

For my Laythe missions I generally use multiple craft. One for landing personnel (generally a base), one for lifting them off the moon into orbit, and another to bring them home. If I were to do a single craft to land and pick up data, rather than process it in a base on the surface, I'd go in the direction of overkill. If you've unlocked the vector engine, that if your best bet. It has the highest in atm to vac ISP ratio. One or two of those pushing a jumbo orange tank with a one person capsule on top should do the trick nicely.

[septemberWaves]

Laythe is like a slightly smaller Kerbin. Any engine you wouldn't use for a Kerbin ascent is one you shouldn't use for a Laythe ascent. Terrier engines and Poodle engines may work on Duna, but they're thoroughly useless on Laythe. If you want to design a Laythe lander, build as though you were building for Kerbin and just scale down a little.

[Rune]

Any Kerbin SSTO will work in Laythe. Laythe-specific SSTOs will only have moderately less demanding design specs. And staged landers will only have marginally lower mass, but they will need heavier transfer stages to get them there. What I'm getting at is, if you build a Kerbin SSTO, you will have a heck of an universal lander that can get itself places, given local refueling assets:

 

Rune. It doesn't even need to be that big.

 

[bjerrang]

Ill try this one. 

Any toughs ? 

Swapped the sience jr and service bay after a slight misshappen in reentry of kerbin

Edited February 26, 2018 by bjerrang

[Spricigo]

53 minutes ago, bjerrang said:

Any toughs ?

Put draggy things inside the service bay (that include RCS thrusters)

Where is the CoM (both fuelled and dry)?

[bjerrang]

Does rcs thrusters work inside service bay (how many)? 

Its pretty full in there. 

Com ? commander ?

There is a small 16-s on lander and a planned hg55 on my transferstage. 

There is a small reaction wheel inside service bay aswell

PB nuk  inside siencejr. 

[Rune]

1 hour ago, bjerrang said:

Ill try this one. 

Any toughs ? 

Swapped the sience jr and service bay after a slight misshappen in reentry of kerbin

That should work beautifully, tough those legs are quite flimsy (doesn't matter, since you have those nosecones to work as landing gear/airbags). Yes, RCS thrusters work inside anything (though they will have less control momentum if they are close to the CoM), they only get disabled if they are tagged as 'occluded' inside a closed cargo bay and/or service bay, and you don't need to have those closed in space. And CoM, of course, is Center of Mass. But if you mouseover over any underlined word in a post, like TWR for example, the forum will provide a list of common meaning for that acronym.

 

Rune. Handy feature!

Edited February 26, 2018 by Rune