Hi,
tl;dr
MK3, 58 parts, 4 Kerbal, cargobay, dockingport, RCS, no clipping, no lost parts, runway, splashdown, swim-inspection, takeoff, 140k orbit (500m/s spare), deorbit, runway-land, takeoff, coast-water-splashdown, moved-to-coast-using-jets
Full Story
I created multiple crafts for this challenge but found it hardest using MK3 parts (And I wanted to be the first on this challenge using MK3 ;)) so here is my participation, its called HAMMERTIME, just because... I dont know - it kind of hammers to orbit
My design goal was to make it easy and enjoyable to fly. It took my about 5 hours to design and tune - it could easily be tuned for better lift performance or efficiency but then it would not make so much fun to fly.
The only mod in use was Flight Engineer.
Some Facts:
Mass: ~87t (~52t fuel) = 35185 kg dry
Crew: 4
Engines: 4 Whiplash, 1 Vector
4 Airplane Wings (MOAR LIFT!!!)
Flight log/profile for this challenge:
Throttle full, SAS on, Turbos on (using 1-key)
Take of between 70 (yes, really) and 100 m/s
Level out at 100m height to reach water
Turn off engines, enable brakes
Touch down on water (undeploy brakes before splashdown!) under 70m/s (it even is possible to land leveled out with under 50m/s)
Do the Vessel inspection (I could not resist doing a group photo of all 4 Kerbals )
Takeoff, engines full throttle, at 70m/s pull up to leave water (easy with so much control surfaces and lift)
Ascent is also easy, this was the part I tuned the most: Just ascent between 10° and 15° and you will reach a height of 20km at about 1000m/s (This craft is more a plane than a spaceship so going faster earlier would burn it)
At a height of 20k enable vector engine (using 2-key) - just let the jets flame out (or disable using 1-key), increase ascent to about 20° until your apoapsis goes to the desired height (I did 85k)
Circularize the orbit. At this point I f**ed up (happy little accident) and did a 144k/140k orbit
At this point I had about 500m/s delta-v still in the tanks - plus LF for the jets. If you are at 75/75 you have 650m/s, so no mun or minmus without refueling. But you can also put 15t of cargo to 85/85k.
The descent is the only tricky part, but it can be archived (with Air-Brakes deployed) following one rule: Keep the vertical speed below 50m/s (at heights between 38.000 and 25.000k meters) using an AOA between 10° and 40° - archiving this can be easier if you pump some fuel to the front. You won't exceed 75% heat (of the 1200K airplane wings, they are the week-point).
If you want to reach KSC from 140k height you need to burn retrograde to an PA at 0m exactly at the opposite to the KSC (From 75/75km burn 50m/s retrograde at the crater).
The challenge says you need to land on KSC runway OR water-land at any coast. I decided to do both - first land (unpowered!) at KSC runway and lift of again to water-land at the coast next to the KSC.
I am quite happy with this universal-easy-to-fly-spaceplane (just KEEP THE VERTICAL SPEED BELOW 50m/s AT DESCENT ), in atmosphere it flies like a big fighter) - I will use it as my new default cargo SSTO.
Album URL: http://imgur.com/a/1eIdg
Craft File: https://drive.google.com/file/d/0B6w6PHP0FfB2bTIxNFBDd2x1U0E/view?usp=sharing
Have fun,
sphere