Trade shipment to the island runway

[Pds314]

Mission

The aim of this challenge is to build a trade vehicle that can deliver bulk cargo to the runway island both quickly and cheaply, getting return on your investment as fast as possible.

 

Scoring

1. Cargo will be represented as ore.

2. Sale price of the cargo will decrease when cargo is shipped at high rates, reflecting price elasticity and saturation of the local market. The formula is

Sale price per unit of ore = 0.1*(ore/time)^(-0.25)

So if you ship 1500 ore in 1500 seconds, you will make 150. If you instead ship 30000 ore in 1500 seconds, you will make about 1419.

3. Spent resources or lost or discarded parts will be deducted from your earnings. That is, 0.6 per unit of solid fuel, 0.8 per unit of liquid fuel, 0.18 per unit of oxidizer, 0.02 per unit of ore (yup, you have to buy this stuff, even if it is pretty cheap). If you burn 50 units of LF delivering your ore, that's 40 cost. If it's 1500 ore, that's 30 more cost.

4. Additionally, as pilots and remote operators have wages, there will be an additional deduction of 0.01 per second. So if you take 1500 seconds to deliver your ore, that will be an additional 15 cost. This applies regardless of if there is an actual pilot.

 

The goal is minimize ROI.

ROI = trip time * empty vehicle cost / ( sales - expenses )

 

So if our hypothetical vehicle cost 10000 empty, and spent 40+30+15 = 85 to deliver 1500 ore in 1500 seconds, that's a profit of 65 per 1500 seconds. Or about 231000 seconds of ROI.

 

Rules

No exploits allowed. Including aero exploits.

Build your craft in a sensible way without unjustifiable clipping or offsets.

If you want to do something wierd like ISRU for ore or fuel, I won't stop you. However, you may not sell any surplus fuel you end up with. Your fuel bill can be zero but it can't be negative.

If you build a boat, I will let you cheat it into the water. However, it should be very close to the coastline and at close to zero speed with cheats off when you start the timer.

The time stops when you're stationary anywhere in contact with the island.

[Pds314]

Because of the way sale prices work, I realized that some really marginal runs might actually have a better ROI if you maintain artificial scarcity by doddling around on the runway for several minutes, asserting your dominance by proving how desperate Kerbals on the island really are for your ore.

[Blaarkies]

Looks like an interesting challenge!
With electric propellers from Breaking Ground the fuel cost can easily be zero. Will you make an example run to show what the challenge could look like?

[Pds314]

5 hours ago, Blaarkies said:

Looks like an interesting challenge!
With electric propellers from Breaking Ground the fuel cost can easily be zero. Will you make an example run to show what the challenge could look like?

Yeah I think I will have to wait until tomorrow. Props and even full electric ARE allowed but of course fuel is far from the only concern.

 

[jimmymcgoochie]

Interesting, I see no cost value for using fireworks as propulsion… 

[FleshJeb]

I think this would be even more interesting if you included round trip time including reloading for the next trip. This would either require dropping off/picking up full ore containers or jettisoning/draining/fuel-transferring the ore.

[ralanboyle]

Well, somebody needs to stop talking about doing it and just do it! I’m book marking this for next week when I’m traveling. 

[ralanboyle]

@Pds314, I think it's rude that no one has submitted an entry for your challenge. So I took 10 minutes to throw together a simple, quick run. I am 1000% sure it can be beaten but maybe it'll serve as a benchmark. I'd like to do this if we can get some competition going. 

I don't know how to do your scoring so here are the specs: 161 seconds, 40 units of fuel, 600 units of ore. Plane at take off costs 17,332.

 

Edited July 8, 2021 by ralanboyle

[OHara]

I tried it with a prop plane with the Breaking Ground mod. Craft and album at KerbalX.

In KSP, 4m² of solar panel is enough to power two electric motors to propel a 17.6-tonne aircraft at 425 knots.

Variable-pitch props are useful for slowing the craft upon arrival, but it still takes some planning ahead to slow down in time.

I thought I would be clever, and install Making History and enable the Island Runway as a launch site, so I could let KSP's recovery menu figure my costs.  However, KSP does not credit us the cost of the variable-size motor in recovered BG electric motors, only minimum cost of the motor.  So by KSP's accounting, it is a money-losing venture:

SalesPrice : ¤0.1 √√(257/1200) = ¤0.068 /ore
Revenue : ¤0.068 × 1200 = ¤81.6
Expenses, ore: 1200 × ¤0.02 = ¤24
Expenses, motor winding : 2 × ¤105  = ¤210
Expenses, salary : 257s × ¤0.01/s = ¤2.57

Profit: 81.6 − 24 − 210 −2.57 =  −¤154.97/trip
Capital : ¤17 085

ROI : −¤154.97 / ¤17085 / 257s = −0.000 035/s

Edited July 11, 2021 by OHara
If we leave out the cost of motor windings, we profit ¤55 per trip, ROI 0.000 013/s

[Ksp Slingshooter]

Making a loss seems against the spirit of the challenge. @Pds314 are you sure that the ROI can be negative?

[Deddly]

9 minutes ago, Ksp Slingshooter said:

Making a loss seems against the spirit of the challenge. @Pds314 are you sure that the ROI can be negative?

Sounds realistic to me. ROI in real life can easily by negative.

[Ksp Slingshooter]

I don't think any company would like to make a loss. Unless, it's an emergency or humanitary help

[Deddly]

9 minutes ago, Ksp Slingshooter said:

I don't think any company would like to make a loss. Unless, it's an emergency or humanitary help

Negative ROI just means the design needs to be improved upon to gain profitability

[Ksp Slingshooter]

8 minutes ago, Deddly said:

Negative ROI just means the design needs to be improved upon to gain profitability

So, the challenge is to make the worst possible design?

[OHara]

Oops, I took ROI to be literally "return on investment" but @Pds314 meant for us to calculate the time of operation required to earn back our investment.

And if I ignore the KSP recovery calculation, I do not have to pay for wear on my motor, so the 'Orer' propeller craft would score:

SalesPrice : ¤0.1 √√(257/1200) = ¤0.068 /ore
Revenue : ¤0.068 × 1200 = ¤81.6
Expenses, ore: 1200 × ¤0.02 = ¤24
Expenses, motor winding : 2 × ¤105  = ¤210
Expenses, salary : 257s × ¤0.01/s = ¤2.57

Profit: 81.6 − 24  − 2.57 =  ¤55.03/trip
Capital : ¤17 061  (empty craft)

Flight time to pay back the investment : 257s × ¤17061 / ¤55.03  =  257s × (310 trips)  =  79 700s 

 

Not every method will make a profit at this. 

@ralanboyle's jet spends ¤32 on fuel plus ¤12 on ore at the source to carry ore that sells for ¤43 on the island.

An SRB needs ¤492 worth of solid fuel (the 820 units in a Thumper) to throw 600 units of ore at the island, which ore sells for under ¤60.

Edited July 11, 2021 by OHara
clarify that it is not difficult to make positive profit, but not every method will profit

[ralanboyle]

Thanks @OHara for breaking down the math. Maybe I can do it now... I went at it with the cheapest plane I could manage with a reasonable amount of ore. 

 

SalesPrice : 0.1*(210/360)^(-0.25) = 0.114 /ore
Revenue : 0.114 × 210 = 23.94
Expenses, ore: 210 × ¤0.02 = 4.2
Expenses, Fuel : 12.28 × 0.8  = 9.82
Expenses, salary : 360s × 0.01/s = 3.6

Profit: 23.94-4.2-9.82−3.6 =6.32/trip
Capital : 4959  (empty craft)

Flight time to pay back the investment :      6.32/360s = 0.018/sec,       4959/0.018=275,500s (766 Trips)

Looks like my fuel crushed me. I'll have to go electric. 

[snip]

 

Edited July 13, 2021 by Gargamel
Video Snipped

[OHara]

20 hours ago, ralanboyle said:

Looks like my fuel crushed me. I'll have to go electric. 

Based on your recent efficiency challenge, I thought a bigger is better approach would cut the fuel costs sufficiently.

I chose the Wheesley engine for its efficiency and loaded as much ore as I thought it would successfully push to the island (KerbalX link).  A built-in angle of incidence to the wings gives it a 9:1 glide ratio so I can get there on 20u of fuel.  It was a challenge to get that heavy craft stopped on the island runway.

I came close, but could not quite beat the prop plane
(at least not without a lot more practice at quickly slowing this plane down to land).

SalesPrice : ¤0.1/ore ×  √√(309s/1800ore) = ¤0.06437 /ore
Revenue : ¤115.86
Expenses, ore : ¤36
Expenses, fuel : ¤16
Expenses, salary : ¤3.09

Profit : ¤60.77/trip
Capital : ¤16 205 (empty craft)

Flight time to pay back the investment : 266 trips  =  82 400 s

[ralanboyle]

Yeah, I thought the same thing. Efficiency is almost always found in scale but @Pds314 addressed it in his scoring system. The question is how well his balance actually works. I did a super tiny run (which was removed by a moderator for having an inappropriate (but clever) name.) So now, its time to GO BIG! 

[ralanboyle]

Welp... Bigger is not always better on this one...

SalesPrice : 0.1*(46,500/341)^(-0.25) = 0.029 /ore
Revenue : 0.029 × 46,500 = 1,348.5
Expenses, ore: 46,500 × 0.02 = 930
Expenses, Fuel : 0
Expenses, salary : 341s × 0.01/s = 3.4

Profit: 1,348.5-930-3.4 =415.1/trip
Capital : 1,151,449  (empty craft)

Flight time to pay back the investment :     415.1/341s = 1.217/sec,      1,151,449/1.217=946,137s (2,775 Trips)

 

 

[ralanboyle]

Sales Price : 0.1*(4,500/383)^(-0.25) = 0.054 /ore
Revenue : 0.054 × 4,500 = 243
Expenses, ore: 4,500 × 0.02 = 90
Expenses, Fuel : 0
Expenses, salary : 383s × 0.01/s = 3.8

Profit: 243-90-3.8 =149.2/trip
Capital : 37,028  (empty craft)

Flight time to pay back the investment :     149.2/383s = 0.39/sec,      37,028/0.39=94,943s (248 Trips)