N12 'Slowpoke' Training Rocket

[ellindsey]

Presenting the N12 \'Slowpoke\' training rocket.

This is not a rocket that is going to win any awards for design or efficiency. It uses multiple mods, including NovaPunch, Silisko Industries, and the incredibly hax Fatboy XL fuel tanks. It has the aerodynamics of an oil refinery, turns like a cow, and crawls to orbit with agonizing slowness.

It is however very, very stable, has insane delta-V, and is really handy for learning to pilot rockets. It\'s also version 0.13 compatible.

This is my first decently successful rocket. Initially the design was meant to make a rocket that was stable, after having too many designs that span out or tumbled when I tried to make the turn to orbit. I started from scratch with a design that had many widely spaced, low-thrust rockets, widely spaced RCS quads, lots of RCS fuel, and a short, wide design that would be very controllable in turns. The overall thrust-to-weight is barely enough to reach orbit, but those 12 Nerva engines are absurdly fuel-efficient so this rocket can take its time, and the low acceleration gives you more time to correct for mistakes.

After I learned to reliably make orbit, I added landing legs to make it useful for practicing vertical landings. This also led to me adding a lot of cross-struts to keep it from snapping apart on rough landings, and a really robust escape system for aborts.

Now, the absurdly capacious Fatboy XL tanks and the Nerva engines mean that this thing takes forever to run out of fuel. This is really helpful for leaning how to do orbital adjustments by trial and error - you can completely screw up your orbit and still have enough fuel left to correct it and try again.

The initial version of the rocket had 4 fuel tanks. The full version here has an extra 4 tanks, which give it enough range to make it to the Mun, jettison the spare tanks, land, take off, return to the launch site, and land intact in the ocean - or even on land, if you\'re a really good pilot.

After a successful vertical landing on land. The design has a lot of heavy parts on weak mountings that like to snap off if you have any horizontal speed or touchdown. Spamming cross-struts on everything helped correct that to a degree.

An unsuccessful landing. Hey, the capsule survived, and the crew are surprisingly cheerful about the whole thing. Note the landing gear/engine/secondary fuel tank assemblies in the background. These broke off from the main body intact, engines still firing, and were zooming around in circles on the ground for a while after the crash.

Successful abort after another failed landing. The side-mounted pusher escape rockets work pretty well for getting the capsule away from the rest of the rocket. The crew are pretty happy about this flight too.

Headed for the Mun. I don\'t know what Bill and Bob are so freaked about.

Jettisoning the fuel tanks. Note that the fuel tank on this rocket are mounted above the main tanks and engines. To jettison them, you trigger the low-energy mechanical disconnects, then gently back away from them with the RCS. Do this only while in orbit. Attempting to jettison the fuel tanks while in an atmosphere is not recommended.

And the fuel tanks drift away in formation. Let them get clear before starting your descent from orbit so they don\'t catch up with you.

Landing on the Mun is nerve-wracking with this design. It\'s very stable, but the 12 Nerva engines are sized to lift off from Kerbin with a full fuel load. Here we\'re landing on the Mun and have burned half our fuel, so the engines produce far too much thrust. To land I need to keep the throttle near minimum to avoid just flying back out into space. There\'s not much granularity to the throttle, so I have to constantly jog the engine up and down one throttle step to control vertical speed.

Touchdown on the Mun, without any parts breaking off! Jeb looks surprised, the others are just happy to still be alive.

Returning to Kerbin, landing in the ocean off the coast of the launch complex. The rocket is capable of landing on the ground, but my piloting skills are not very good, and I was running low on RCS fuel. One important thing I learned about the design is that is important not to have any aerodynamic parts - fins or wings - on this rocket. Having fins means the thing will want to turn into the direction of flight when hovering sideways, which rapidly leads to more sideways speed and tilting over beyond the ability of the RCS to control. This thing needs to be as aerodynamically neutral as possible.

Nearly out of RCS fuel, landed with a bit too much lateral speed, and one of the Fatboy tanks was destroyed on contact with the water. Good thing it was nearly empty. The rest of the rocket floated intact and was theoretically recoverable, so I\'m calling this a successful flight.

The parts used here are a bit hax, so the fact that it can go to the moon, land, take off, return to the launch site and land again with only some fuel tanks jettisoned isn\'t much of an accomplishment. Mostly this design has been really helpful as a forgiving platform to learn to fly and land a rocket.