Flieger, grüß' mir die Sonne, grüß' mir die Sterne und grüß' mir den Mond. Dein Leben, das ist ein Schweben, durch die Ferne, die keiner bewohnt! - Hans Albers, F.P.1 antwortet nicht (Adaptation in the 80s: Extrabreit)

Saturday, 8 August 2015

Mün rover racer

With renewed energy, I tackle the construction error of the White Goose spaceplane. And lo and behold, just about 15 minutes later, it is solved. The tips from the forums which I copied&pasted in my last blog entry were not entirely applicable, though. But the theory behind was.

- this is the struts how I had them at the end of last session

The theory is that the plane must have its lift applied evenly accross all sections. With my plane, I found out that the aft landing gear was the culprit; it was placed too much frontal. My earlier versions had it placed more in the back, close to the engines. Indeed, it was because of those forum tips that I had placed the landing gear more forward, in order for them to be closer to the center of mass, for an easier and faster liftoff. It turned out that this closeness to the center of mass made the wings bow upwards from the weight. That, or, the wobblyness of the middle part of the engine nascelle was the culprit; only the back part is strutted. But I have had enough of test launches and want to get on with my missions.

As a conclusion, I will pay attention that the triangle of the position of the landing gears must always have the center of mass in its center. If not, there is too much weight imbalance, which eventually will cause the plane to veer off at higher roll speeds. And struts, always.

- this is how it works fine now

Just to be sure, I also added one more strut at the front, and some small ones connecting the engines in the aft to each other. Presto! But what a fight to finally get back to a working plane. I guess this also proves the saying, never touch a running system.

I also added a small experimental detail: A heatshield in the front of the cargo bay. Even though I only can install it as a packed version, it seems to work, heat gauges still show, but non anymore throughout the ascend and only green heat gauges during re-entry!

- much better heat tolerance

I still have to reload once, but this is because I forgot to put the test equipment from that mission contract not into an extra stage, so it fires off too early. Then, finally, I can check off two tourist contracts and a test contract.

They get immideately replaced by new contract offers in the mission control center. Two satelite missions and a rescue mission, an ideal combination for which the Firebird (former labelled as Cargo Shuttle) was made for.

- not again please...

This mission launches fine, even though the Firebird has a similar wing construction problem, but this bird does not misbehave, so I leave it at that. One satelite is for a polar Mün orbit, one for an escape trajectory out of Minmus (I don´t ask what purpose this could have). The last maneuver for the rescue mission will take a bit, since I was too lazy to time the launch for a proper close intercept position.

Since my Minmus missions are basically finished, with the Navitas digging for ore/fuel in the meanwhile, I can now turn towards my Mün expedition. I want to first use and test the Yawl. Right at that moment, there is an area with some closer-neighbouring biomes below, so I make a hasty undock.

- no time to admire the skyline

For the landing, I watch the KER figure for the suicide burn, but again, like during my first Mün landing, the figure is wrong, so I am burning too late and crash horribly. Reload. Crash again. Apparently, the landing gear is not really up to compensate an impact with 50m/s, even though its description says so. Two crashes later, I found the sweet line at about 20m/s. After all, I wanted the landing gear instead of landing struts in order to save deltaV by having not to decelarate so much.

Eventually, the Yawl has a touchdown on Midlands, short before dawn. Starting all science experiments, the JR lab is not reachable from top. Dismounting via the ladder is also a problem, I attached it too low, causing my Kerbonaut to fall off.

 - going through all engineering errors

Then I start to drive around. The wheel motors do have some trouble accelerating the boat on upward slopes. At about 20 m/s, the rover becomes unstable and hops on slight bumps. And the distances, they are really huge. 20 minutes of driving, and I haven´t yet arrived at another biome, which seemed to be so close by as seen from above. As I have to climb down a steep slope into a crater, a moment of inattention at max speed and the rover topples.

- quite overdone for a simple sommerault, no?

Sigh. And reload, loosing the last hour of gameplay or so. I shudder to think how many Yawls I would have had to bring here if I played "iron man" style...

This time, I try to land even closer to a spot which is close to three biomes. A Mün map download from the kerbalwiki helps me to do so.

- I choose a spot south of the polar crater

After some more driving around, I get a bit frustrated by the weak motorpower; steep slopes get the Yawl down to a crawl of 4m/s at most. Also annoying is the fact that rover wheels, even thought they are rated to have a braking power of 30, cannot stop the Yawl at a steep slope from going backwards down. The landing gear, with its nominal torque of 17, do manage, on the other hand. Since it is still not dawn and the batteries are almost depleted, I park the vessel.

Some maneuvers concerning my two satelites mission serve as a diversion and help me to finish the game session on a lighter mood; after all, the rover test so far was more on the disappointing side.

- test contract for spider engines, which make for good satelite engines, and an occasion for witnessing a nice scenery

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