Kerbal Dynamics: The Ultimate Skycrane

[ihtoit]

The Boffs just handed me another note:

"Today's challenge is to build a long-range, heavylift helicopter and use it to deposit a manned science package near the object at 81D57M North, 128D30M West (altitude shy of 100m), collect science (especially ground samples) and return the helicopter and all Kerbals with collected science to KSC leaving the science package behind with a marker flag."

Sounds complicated. It probably is.

THE RULES:

- ALL structural mods valid.

- No OP gear, exploits, cheats, hyperedit, infinite fuel or any of that other stuff.

- Transporter MUST be manned.

- Transporter MUST be of the strictly helicopter variety: the lifting force must be provided by rotors (Firespitter recommended).

- Science package MUST be detachable intact with capsule accommodation for at least one Kerbal.

SCORING:

250 points for safe landing at target coordinates.

250 points for returning to KSC.

250 points for doing both flight legs WITHOUT refueling (not even with Kethane mining, processing SPH-load kethane is OK though!).

100 points for utilising kethane for fuel/oxidiser generation.

1 point for each Science point gathered. You may use ONE orbiting relay to transmit Science back to KSC.

Science Points proofs:

Cropped screenshots (to save loading time) for transmitter status Science points transmitted (where used).

Other proofs:

Regular screenshots at each leg.

Recovered Science.

This is a "free design" challenge. Obviously the more Kerbal your design, the better, but bear in mind fuel consumption versus carrying capacity. Flights are likely to take a while (my kethane helicopter, which could barely make 6km altitude, took 35 minutes or so to fly 400km).

(Challenger's Note: I'm going to try this one out with my kethane rig writ large (with a full kethane tank), with extra fuel in drop tanks for a hop-flight outbound to target (I already have all the kethane deposits mapped but with extra tanks I shouldn't need to stop for a refuel), once the aircraft has dropped its load and is very much lighter it should be a case of a one-stop to the kethane field to the NE of KSC, mine some and refine some fuel then a leisurely flight back over the Northern peninsular mountains. I won't be scoring on science since I do all my proving in Sandbox mode, though there will be some screenshots).

Challenger's entry: ongoing: the Kerbal Dynamics Hercules HLT (HeavyLift Transport), ironically it's way less than 20t on the runway! I hope it's got the fuel economy to at least make it to a kethane field! Oddly, I couldn't find a way to fill the kethane tank so it went up empty (me 'tard?), so the transporter actually settled on the payload until the drop tanks kissed the tarmac! No harm though!

Powerplant: twin meshing Bear rotors, 2x1200W batteries, 2x 1x6 solar arrays (for the two kethane drills and the onboard refinery), twin outboard LF tanks and six drop tanks.

Vehicle part count (with payload): 79!

HLT in flight:

EDIT: this bird needs to be a LOT bigger. Barely got half way before running out of gas! I think those Bear rotors are a bit of a fuel hog.

Edited April 1, 2014 by ihtoit

[Darren9]

Could you show a map/zoomed out view and point to it? Also can any propellers be used (VTOL, electric or even one lift and another forward for example), and must each leg be a single flight? A battery-electric-solar-RTG seems possible, if it had to land and recharge or even wait overnight that would count as refueling?

Edited April 1, 2014 by Darren9

[ihtoit]

ok...

1. it's just inside the ice cap to the North North West of KSC, approx. 800km. I'll post a screenie just as soon as I land. For now, here's a very rough approximation of the position of the object. KSC is over the horizon:

2. yes. As long as the primary lift is via horizontal rotors not wings, you're golden.

3. No, you can stop to refuel (possible options are jet tankers with KAS connectors, preplaced at specific rendezvous points, or the two major kethane deposits en route (one off to the East which takes you a bit out of the way, another one on the direct path which covers a good chunk of the ice cap), to name but two options that I myself have considered - I figured it's a lot easier to just watch the one aircraft and kit it for kethane, so that's what I went with).

4. No, it wouldn't count as refueling if you're not taking on combustible fuel. A nuclear powered helicopter is an option, too!

Edited April 1, 2014 by ihtoit

[Darren9]

Thanks, there is one other thing. A "manned science package", is that a large manned lab or a small science, a goo and a cabin would be good enough. I uninstalled all the nuclear stuff to stop some memory overflows and this could greatly effect the number of batteries and solar panels I need.

[ihtoit]

yeah I just used a MK.I can and kept pretty much to the stock sensors with the exception of that rather handily placed kethane scanner on the nose of the transport and I think the ore scanner isn't stock either. Obviously if you use a MPL you can rerun goo experiments and Science Jr (or whatever the deployable package is called) and spam the snot out of your Science score, but whatever you collect Science on MUST be attached to the Science capsule and left behind with it.

This is an early development test flight. The large batteries (2 of) on the Science can were replaced with a single stock battery as they were too heavy. Stock sensors are on the other side of the can, one pair of solar panels (with no heatsinks), and no parachutes on this version because I thought I might try and be clever and do a low altitude drop onto the landing gear (suffice it to say, that didn't work). Also, the docking ports were swapped out with a decoupler and cubic strut to save a lot more weight.

Edited April 1, 2014 by ihtoit

[Fengist]

I think your distance is off a bit. It's more like 1,000km. Annnndddd... I seriously doubt anyone will get a 'helo' that kind of distance. If you remember my ultimate helo challenge, even I had a rough time getting to KSC2 with a helo and that was with 2 turbofans pushing. Even the other competitors were pinched for fuel. If you open this up to all props then only one has the power & efficiency to really make it (unless you stack gobs of little props) and that's the Lancaster engine. In which case, you're a VTOL. If you have to send a jet to refuel then what's the point? You might as well load your cargo onto a jet in the first place. Or at least a SVTOL. You said once that you had flown real helos. If that's the case then you should know that they're not super efficient at carrying cargo long distances.

Now, let me strap on some jets and I'll give this a shot. Otherwise, it's a looong boring flight at Lancaster speeds.

Oh, and by your rules definition, THIS would qualify (and probably make it but I'm not up for that long of a boring flight) even though it's anything BUT a helo or a sky crane.

[ihtoit]

ok, jets are fine for forward thrust (most modern helicopters do have either tail-facing vectored engine exhausts or dual-function jets (the Jetranger II has twin jet turbines that run the main rotor and provide all the forward thrust, landing one is tricky as you have to throttle back and pull the collective all the way back but keep the nose down with the control ailerons to cancel forward motion - KSP is a lot simpler, you can just add the jets toggle to an action group and switch them off during takeoff or landing)), but are those wings I see outboard the engines? And is this a VTOL or a STOL? Never mind, I just spotted the landing gear. I would say no unless you swapped the winglets for fenestrons if you're claiming that they're there for control authority - those particular ones do have a lot of lift. The distance is right, as the crow flies it's something like 800km from the runway (I'll do a target lock from the runway later today).

As to the range issue, it's a question of fuel fraction. The problem I have with my designs is that they're only about 10% fuel, I need to get that fraction higher. Distance records shown here concern some aircraft adapted for the attempt. That said, unmodified helicopters hold most of the records (the Hughes OH-6 model 369 has a ferry range (maximum internal fuel load, no payload, one pilot and no passengers) of 3560km on just its one internal tank, we're talking a fuel fraction of more than 50%). My own version of this bird (the KD Miniranger) has a max range of 200-someodd km one one fuel load with two passengers, but there again we're talking standard aero model, stock 1.25m LF tank and a vehicle loaded weight of less than 3.5t. I'm pretty sure it'll be about half again with FAR.

Edited April 3, 2014 by ihtoit