The perils of 100% recovery

[Thanny]

Putting your rocket bits down on the runway is the easiest way to get 100% recovery, so that's what I've been doing since 0.24 came out. It takes a bit of practice (and sometimes a few reloads) to get it right on the runway with no extra burns, but it's a lot easier than trying to hit the launchpad.

Today I discovered that since 0.25, there are perils to this approach with larger ships:

I'll be sending a tanker up to my fuel depot soon, so I'll see if adding more chutes to bring the descent speed down makes a difference.

[SelectHalfling0]

The runway really annoys me now. Even though I built very few large space planes, most cause the runway to explode. I would like to say that ship was moving very slow for it to damage the runway.

[Tygroux]

Yeah, the runway is bugged right now. I can't use any of my heavy-duty lifters or test my big planetary rovers because they cause the runway to implode under the weight.

Edited October 13, 2014 by Tygroux

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That is crazy. I've had planes do somersaults down the runway and it didn't do that. I've even intentionally nosedived into the runway with a 3.75 rocket at full thrust from 10,000 meters and it didn't blow up.

[Pecan]

Just landed a 400t (at almost dry) SSTO rocket on the launchpad. Drogues reduced descent to 11m/s, residual fuel reduced it to 5m/s.

The launchpad blew-up.

(Initially the launchpad blew-up when I tried to launch the thing in the first place but launch-clamps keeping it off the ground got over that).

[tg626]

It seems to respond strictly to the weight placed upon it. In truth, all surfaces would have a limit to the weight that could be placed on them without damage/collapse. That said, in a game where you could place a 400t monster on the very edge of the shore and not have it sink an inch (let alone explode the beach) it seems a bit misguided. They'd be better off with taking the impact velocity into account and letting the weight be ok as long as you touched down slowly.

And all that aside, THIS is the reason for destructible buildings - not look what fun it is to wreck it all - THIS; adding peril to attempting to get that 100% recovery.

[bitbucket]

This is why I turned building damage off.

[RW-1]

Yeah, the runway is bugged right now. I can't use any of my heavy-duty lifters or test my big planetary rovers because they cause the runway to implode under the weight.

I had the same thought when I placed a larger booster on the pad and .... Boom!

Now we need the launch clamps to hold them off a bit.

[r4pt0r]

Is there going to be a hotfix for runway strength?(and maybe removing the fiery effect, and just having a smokey concrete dust cloud look?)

[problemecium]

I have a strategy active that improves my recovery payouts, so even on the KSC grounds or a short distance away (e.g. in the water just offshore) I get 100% recovery value. I recommend this.

[Blind Dead McJones]

That is kinda silly and hopefully they'll make it a little more robust, but remember that it probably wasn't designed to have a 300t rocket land on it. Your best option is probably to land in the ocean right off the coast and accept 98% recovery. Alternatively, don't make rockets that big.

Also, minor point, but please don't make silent videos. It just seems really lazy and amateurish. If you don't have the sound from the game, at least add narration or music or something.

[r_rolo1]

Hum, a C130-H ( that is not by far a heavy plane ) has a dry mass of 34.400 Kg with a max weight at take off of 70.300 kg ( wiki ) . A fully loaded C-130H will need a V2 of excess of 100 knots ... so if you do the math , the KSP runway would most likely explode under a fully loaded C130-H at takeoff. Not good, not good ...

And this is not even speaking of the Boeing Gumpy line, the Airbus Beluga or , god forbid, the An-124 :/

[Thanny]

Also, minor point, but please don't make silent videos. It just seems really lazy and amateurish. If you don't have the sound from the game, at least add narration or music or something.

There are quite a few problems with this statement, not least of which is the fact that the video isn't silent, as anyone who actually watched it would know. Which is a shame, because I'd like to explain why every single thing you've said is wrong.

[born2fly145]

You know, in reality, runways are actually pretty susceptible to damage. I actually tore a hole about 5 feet across once upon takeoff from an asphalt runway in a heavily loaded 747. The engine thrust downward during rotation caused the damage. In addition, many Air Force bases won't allow Harrier VTOL jets to land vertically on their runways, especially if they're asphalt. Concrete runways hold up better, although they're not invulnerable. They're also more expensive and time consuming to repair. With this in mind, I'm not surprised they collapse in KSP when a rocket lands on them vertically or a heavy craft hits hard.

[r_rolo1]

Thanny, yeah, your video has sound , but you have to agree that it is pretty quiet until 0:46

EDIT:

You know, in reality, runways are actually pretty susceptible to damage. I actually tore a hole about 5 feet across once upon takeoff from an asphalt runway in a heavily loaded 747. The engine thrust downward during rotation caused the damage. In addition, many Air Force bases won't allow Harrier VTOL jets to land vertically on their runways, especially if they're asphalt. Concrete runways hold up better, although they're not invulnerable. They're also more expensive and time consuming to repair. With this in mind, I'm not surprised they collapse in KSP when a rocket lands on them vertically or a heavy craft hits hard.

Yeah, but tell me the first time you explode a 100 m section of a runway by touching down a heavy craft Preferably also record it

In all seriousness, we are talking of unpowered touchdowns and takeoffs without tailstrikes or similar shenanigans ( the OP video is a unpowered landing via chute , BTW ). That should not destroy ( even less explosively ) large tracts of runway in almost no circumstance ...

Edited October 14, 2014 by r_rolo1

[Blind Dead McJones]

There are quite a few problems with this statement, not least of which is the fact that the video isn't silent, as anyone who actually watched it would know. Which is a shame, because I'd like to explain why every single thing you've said is wrong.

I swear I watched the whole video twice earlier and heard nothing. I checked everything too. It seems to be working now.

[Epthelyn]

Also, minor point, but please don't make silent videos. It just seems really lazy and amateurish. If you don't have the sound from the game, at least add narration or music or something.

The video served its purpose; it didn't need music to make it entertaining (because it wasn't necessarily supposed to be, although explosions be explosions) or narration to explain what was going on (because it was obvious what happened).

[merendel]

You know, in reality, runways are actually pretty susceptible to damage. I actually tore a hole about 5 feet across once upon takeoff from an asphalt runway in a heavily loaded 747. The engine thrust downward during rotation caused the damage.

On the other hand that same 747 would have been heavy enough to explode 100m or so of runway into firey rubble just by being driven out onto it. Theres been talk of it not being designed for our 400t monsters yet several 747 models have a max takeoff weight in that range according to Wikipedia.

[Pecan]

...The engine thrust downward during rotation caused the damage...

Any excuse for the landing pad being similarly susceptible?

It is (should be) designed for full-thrust rocket blast at launch, having minor thrust returning shouldn't be a problem. If it is the whole SpaceX vertical-landing idea has to go. However unrealistic part-strength is I also can't imagine any universe where rockets are stronger than their launch-pad such that it's the exploding pad that destroys the rocket, not vice-versa.

[Russoft]

I swear I watched the whole video twice earlier and heard nothing. I checked everything too. It seems to be working now.

I realize it's off topic, but I personally don't mind "game-sound-only" videos. I don't bother watching poorly narrated videos, or videos with music I dislike.

[Thanny]

So as I indicated, I added more chutes (744 radials, 8 XL's) to a tanker I sent up to refuel my depot. The result is a 480t lander (versus ~170t for the first one) with a final descent speed before impact of 4.34m/s.

I've lazily put together another amateurish video showing the result:

Since the game engine is really bogged down by the ship, I started in the middle of the descent, and sped that up by a factor of 10. The rest is running at 1x speed, which is quite slow due to the part count (my subjective impression is that large numbers of parachutes have more of a deleterious effect than any other part type).

Unlike the first ship, this one, had it survived intact, would have justified the runway repair, having a value beyond 1.6M (32K repair divided by 2% penalty). I think I'll be skipping the runway for any remotely large ships until they send in the bomb squad to make it safe again.

[tsotha]

This is why I turned building damage off.

I'm considering that myself. I don't mind buildings blowing up when you hit them, because you're not, you know, supposed to hit them. But landing on the runway at 5 m/s shouldn't damage it. It all seems rather arbitrary, and I don't see what it adds to the game.

[r4pt0r]

Any word on a runway strength hotfix? .25.1?

[Thanny]

After another tanker run, I saved just before chute deploy to try powered descent. I got the 382t ship in the last video down to 2.4m/s before touchdown, and it still detonated the runway.

I might do some experiments in sandbox mode to see just where the line is. In the meantime, I'm killing destructible buildings until they dig the bombs out of the runway.

[magnemoe]

After another tanker run, I saved just before chute deploy to try powered descent. I got the 382t ship in the last video down to 2.4m/s before touchdown, and it still detonated the runway.

I might do some experiments in sandbox mode to see just where the line is. In the meantime, I'm killing destructible buildings until they dig the bombs out of the runway.

Ok so 2.4 m/s still destroys runways, make me wonder how it would work without parachutes at all, perhaps the shock of parachutes getting disabled create the problem. Pure powered decent, this will cost 150-200 m/s

And yes the problem is that its not primarily speed but rather weight who trigger this. Should be primary speed.