[Tip] Reduce tiping when landing on slopes.

[Warzouz]

Landing can be harsh on slopes. Here is a tip I noticed to reduce unlucky tipping.

The obvious : If fuel is drawn fuel from lower tank first (fuel conduits), lock the lower tanks or transfer fuel from the top to the bottom to lower you center of mass before landing.

The less obvious : When you locate the orientation of the slope, "Lock suspension" on the landing struts down the slope. That way, your ship will bounce less when you cut engine.

In any case : land slower than on flat land. Try to get lower than 1m. Of course activate SAS.

Edited August 7, 2015 by Warzouz

[Fearless Son]

I might add, "Have your landing points be widely spaced apart."

Unfortunately, that makes a lander hard to fit in a fairing.

[Red Iron Crown]

The obvious : Engines draw fuel from the lower tank first. So lock the lower tanks or transfer fuel from the top to the bottom to lower you center of mass before landing.

I don't believe this is correct. Engines drain a stack from top to bottom (assuming no fuel lines).

[ajburges]

A slower landing can actually be a detriment. A slope means you are landing off vertical. Even just 6 degrees of slope means you have 10% horizontal thrust. Worse, that thrust takes you away from the ground.

A better bet is to hover a meter above land, then touch down with .4-.7 TWR and stability SAS. The minimal thrust will relax thrust cutoff timing requirements and a hover before touchdown reduces the forces that make landing on a slope hard. This method does waste fuel though. Your often better avoiding slopes period.

[Warzouz]

I don't believe this is correct. Engines drain a stack from top to bottom (assuming no fuel lines).

Well my miner/lander is LVN powered and drain from the bottom. That maybe related to the fuel conduit though... EDIT : true, I fixed the OP.

BTW, I managed to land on a 27° slope on Bop. I don't understand why I can't take screenshot anymore, but my lander look lit that.

(click to enlarge)

Edited August 7, 2015 by Warzouz

[Red Iron Crown]

Well my miner/lander is LVN powered and drain from the bottom. That maybe related to the fuel conduit though...

Pic of the craft? I suspect that you have LV-Ns mounted radially and connected by fuel lines to an upper tank, that would do it. The more conventional lander design of engine at the bottom with fuel tanks above will drain from top to bottom.

More generally, engines will draw from the furthest fuel tank first, if that makes sense.

Edited August 7, 2015 by Red Iron Crown

[Skorpychan]

You're using LV-Ns on a lander, there's your problem.

[Red Iron Crown]

It looks like it's a heavy lander meant to be used repeated on a low gravity vacuum world, LV-Ns are a perfectly reasonable choice for such a role.

[Warzouz]

It looks like it's a heavy lander meant to be used repeated on a low gravity vacuum world, LV-Ns are a perfectly reasonable choice for such a role.

Yes this heavy lander is design to bring back 2 big tanks of Ore to a space station. It's capable of refueling 43% of an orange tank from Moho/Vall, 61% from Mun/Eeloo, 68% from Dres/Ike and 83% from Bop, Pol, Minmus and Gilly.

It's part of a modular space station I'm working on.

[juanml82]

Rovers are the best for landing in slopes. Hover just over the ground, match the rover's inclination to the terrain slope and cut the engines. And have an engineer on hand in the case the wheels break.

[cantab]

If you design your lander so it fits in the fairing "sideways" you can get a wide lander base in a format that easily goes up on the rocket. Example. It takes a little fiddling to ensure it's balanced but it's not too hard.

[GoSlash27]

My new lander designs put the fuel tank above everything else. Low CoG is good.

Best,

-Slashy

[Starhawk]

My new lander designs put the fuel tank above everything else. Low CoG is good.

Are you saying your tank is lighter than the command pod? I'm assuming it's manned.

Happy landings!

[GoSlash27]

Are you saying your tank is lighter than the command pod? I'm assuming it's manned.

Happy landings!

Starhawk,

So far, on all the bodies I've visited the tanks are a good deal lighter than the payload. Certainly when the tanks are partially drained from the descent burn. Probably a different story on places like Tylo...

*edit* doing the math back-of-the-envelope...

A ship with fully loaded tanks exactly equal to the mass of the payload/ engines would have a Rwd of 1.89. Even at 300s Isp, this would translate to about 1,900 m/sec DV. Much higher than would be necessary on almost all moons, and even then the tanks would weigh less than the payload at the moment of touchdown.

So yeah... tanks should be on top.

Best,

-Slashy

Edited August 8, 2015 by GoSlash27

[Starhawk]

Starhawk,

So far, on all the bodies I've visited the tanks are a good deal lighter than the payload. Certainly when the tanks are partially drained from the descent burn. Probably a different story on places like Tylo...

Yeah, I figured that was what you meant. Of course, Tylo popped into my head right away.

Anyway, I still tend to build mine with small radial tanks around a lander can for a wide base. I usually just eat the extra drag on ascent to LKO.

Happy landings! (Low CoG is definitely good!)