Eve Lander Won't Land

[SteveD80]

I am trying to make an Eve lander.  I am testing it with Hyper Edit.  It will finish landing and return to orbit, but currently it flips at around 3000 m/s on descent. I am thinking that I should fill the bottom tank; it is currently empty and exists to provide a launch platform.

http://imgur.com/a/YbK3M

 

[Magzimum]

You need a lot more control surfaces near the top. All those giant 10m heat shields cause enormous drag. A lot of people use airbrakes for that (enable pitch, yaw). Given the number of heat shields, I would think 30+ airbrakes.

There have been several threads on the same topic. I think this is the most recent one:

 

[DrLicor]

Here's a great simple explaination of what @Magzimum said:

 

[crackerbal]

u will find the answer here posted few days ago

 

[Snark]

Yah, the problem is that your CoM is too far away from where all the drag happens (those heatshields).  Put simply:  You want your center of mass to be at the same end of the ship as your center of drag.  Your problem is that you have them at opposite ends.

If your problem is that CoM and CoD are at opposite ends of the ship, then you have, broadly speaking, two options:

One approach is to add drag to the retrograde end of the ship, as folks here have been suggesting (i.e. more control surfaces, airbrakes, etc.).  Personally, I'm not a fan of that approach for Eve landers, mainly because you also need the ship to be aerodynamically stable during ascent, and putting airbrakes etc. at the top end will work against that.

The other approach, which personally I prefer, is to put the heat shields on top of the ship, and enter prograde rather than retrograde.  That way, you can put lots of fins at the back end of the ship (where the engines are), and not only do they help to keep you stable on reentry, but they also serve double duty by helping with stability during the ascent phase as well.

[SteveD80]

10 hours ago, Magzimum said:

You need a lot more control surfaces near the top. All those giant 10m heat shields cause enormous drag. A lot of people use airbrakes for that (enable pitch, yaw). Given the number of heat shields, I would think 30+ airbrakes.

There have been several threads on the same topic. I think this is the most recent one:

 

Well I've gotten rid of 5 heat shields and added 90 airbrakes and am still having problems.  I will read through the thread you linked.

[SteveD80]

13 hours ago, Snark said:

Yah, the problem is that your CoM is too far away from where all the drag happens (those heatshields).  Put simply:  You want your center of mass to be at the same end of the ship as your center of drag.  Your problem is that you have them at opposite ends.

If your problem is that CoM and CoD are at opposite ends of the ship, then you have, broadly speaking, two options:

One approach is to add drag to the retrograde end of the ship, as folks here have been suggesting (i.e. more control surfaces, airbrakes, etc.).  Personally, I'm not a fan of that approach for Eve landers, mainly because you also need the ship to be aerodynamically stable during ascent, and putting airbrakes etc. at the top end will work against that.

The other approach, which personally I prefer, is to put the heat shields on top of the ship, and enter prograde rather than retrograde.  That way, you can put lots of fins at the back end of the ship (where the engines are), and not only do they help to keep you stable on reentry, but they also serve double duty by helping with stability during the ascent phase as well.

I'm not worried about the assent, the airbrakes and fins are attached in such a fashion that they are jettisoned prior to take off.  Though on another thread someone suggested sticking an extra heat shield on top to act as a counter balance for drag.  

I vaguely remember reading about a mod that allowed the shielded docking port to be used as an attachment node in the editor is this (still) a thing?

Edit:

I have been unable to get the rear facing landing to work.  I am currently trying prograde entry and am getting further.  Is there anyway to attach to shielded docking ports in construction?  Is there anyway to stage docked components (I want to carry up the heat shields on the bottom of my lander and move them to the top, and then ditch them through staging when I open my parachutes)?

Also, are there any stock fins with a heat tolerance greater than 2400K?

Edited November 1, 2016 by SteveD80