Efficient Tylo landing?

[waterlubber]

I'm looking for a semi-efficient way of landing on Tylo. My lander has 8km/s of DV, which should be enough. It has 1.1-1.4 Kerbin TWR the entire descent and ascent. Currently, I'm just burning retro the entire way down and throttling a small bit to stop me from re-ascending. What's the way that gives me the most time to burn, and is safest? Hopefully not too inefficient. (I just landed, fell over, and then crashed. as in the game gave me the finger)

Edit: Attempt two. Could not see lander in dust cloud. ;P

Attempt 3-6: These dust clouds. Seriously. I can't see crap.

7: Too fast. Collision at 200 m/s

9: Victory! Locked the suspension. Leaving question, because I is curious.

9 1/2: Forgot the ladders. Good thing this was a test!

Edited June 9, 2015 by waterlubber

[xtoro]

I start burning straight up to kill off my vertical fall and once it's under control I tilt back slowly to bleed off my horizontal speed. If I start dropping too fast again I point back upwards. Just a bit of back and forth looking for the sweet spot till I land.

[waterlubber]

Thanks! I loved Avalon and am contemplating...Jool 5

[cybersol]

The lower my TWR, the more I lean toward the constant altitude method of landing (search for videos). The basic idea is to first use pitch to control vertical descent rate while slowing your orbit speed at constant altitude. Slowing down more at a higher altitude tends to be much safer for the lower TWR landers.

[waterlubber]

I've found that it's best to suicide burn the whole way down . Curious, is suicide the most efficient?

[Starhawk]

I've found that it's best to suicide burn the whole way down . Curious, is suicide the most efficient?

The most efficient is a type of suicide burn. Starting from the lowest possible circular orbit, burn at the opposite side from where you want to land until your periapsis is very close to the surface. How close depends on TWR. Wait while your craft gets close to periapsis (and the surface).

Then burn at the very latest moment that will drop your horizontal velocity to zero at your periapsis. (This may require repeated use of F5 and F9 or mod+F5 and mod+F9 to find the correct timing).

Happy landings!

edit: Of course, the constant altitude method is much easier but burns more fuel.

[xtoro]

Thanks! I loved Avalon and am contemplating...Jool 5

Thanks man, I like hearing from fans of it It's being retooled to 1.x and is a lot more work than I initially thought. Another Jool 5-only mission is floating in my head as well for after Avalon.

Back on topic though, I never had much luck with suicide burns for Tylo and found the method that me and cybersol are talking about works great for me. For some reason I use more fuel trying to suicide burn than to do a more controlled descent. I actually did it that way for the Avalon mission and it turned out quite graceful.

Edited June 9, 2015 by xtoro
spelling

[cybersol]

Most efficient is an inverse gravity turn, where the shape depends on your TWR. With massless, infinite thrust engines you would do a suicide impulse burn a meter above the surface (assuming there would still be a surface after that). With a TWR of 1.00001 you would do something very close to a constant altitude method, because getting too deep in the gravity well with too much vertical speed would cause you to crash and burn. Landing though is one area where I tend toward efficient enough with some extra safety built in.

[Snark]

Key to landing efficiently is that you should always be burning exactly retrograde; anything off that will saddle you with cosine losses. Thus the efficiency of the inverse gravity turn, as cybersol points out.

You also want a reasonably high local TWR, or you really pile up the gravity losses.

[FancyMouse]

steering loss is actually not that big comparing to gravity loss, and if you could pay a little bit steering loss to prevent more gravity loss, you would actually want to do that.

[Xannari Ferrows]

You want to try to bleed off as much velocity as possible in a single burn, and as low as you can make it. Because of the inverse square law, this descent will be more efficient, seeing as you will spend less time higher up, therefore shortening the amount of time you allot yourself to gain velocity by gravity.

This will mean higher TWRs are better, but always make sure it's controllable. Marginal Delta-V is always required.