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The Inefficient Airplane Challenge


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The Goal: Make the most fuel guzzling aircraft you can.

 

The challenge: Fly from the KSC to the Island Airfield.  Use as much fuel as possible within the parameters listed in the rules.

 

LEADERBOARD:

@ralanboyle:  weight 22530, fuel burned 9778, score 2.3

 

RULES part 1 (Single Engine):

1. You may not exceed 3000 meters in altitude.

2. You only can have one engine. 

3.  Any air breathing engine is allowed.  Rapiers may not be in rocket mode.

4.  Landing gear must be retracted except for takeoff and landing. Small craft using the LY 01 and 05 gear are allowed.   No, you may not add insane amounts of gear.

5. Airbrakes may not be used (it is just too easy, otherwise). Airbrakes are defined as the stock A.I.R.B.R.AK.E.S. If you figure out something else, go for it.

6. You must fly straight to the airfield.  No trying to stretch out the distance by flying in a sine wave pattern or in circles.

7. The craft must takeoff and land horizontally. No VTOL for this challenge.

8. Your craft must be piloted. 

9. Stock and DLC only.  

10.  Internal SAS only.  No additional reaction wheels or fly-by-wire.

11. Keep to the spirit of the challenge. Exploit the rules, but don't try to win on technicalities.  If unsure, ask.

 

Your score will be determined by the rather oversimplified and not completely valid formula of initial mass (including fuel) divided by fuel consumption.  Thus a 30,000kg craft that consumes 160 units of fuel has a score of 187.5. The lower the score, the better the ranking.

 

Keep the resources tab open and note the starting and ending values for the liquid fuel:

tJkaybk.png?1

 

RULES part 2 (Multi engine open class race)

Must take off and land horizontally

Must be stock or DLC. 

Must be airbreathing.

Fuel must be burned, not drained or dropped.

No parts may be shed. 

Scoring: (takeoff weight/fuel units consumed)  * flight time. Lowest score wins.

 

Basically, get to the Island Airfield as fast as you can while using as much fuel as you can.  Anything not mentioned above goes.

 

Edited by Klapaucius
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Probably the best (worst?) way to do this will be to have a jet engine angled almost all the way down and as heavy of a craft as possible. Then go full throttle, inch down the runway until your wings provide that extra tiny bit of lift, and float eastward to the island airfield.

 

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19 minutes ago, camacju said:

Probably the best (worst?) way to do this will be to have a jet engine angled almost all the way down and as heavy of a craft as possible. Then go full throttle, inch down the runway until your wings provide that extra tiny bit of lift, and float eastward to the island airfield.

 

I had initially planned to not allow what you have mentioned, but figured that there would be controllability tradeoffs with one engine. Also, there is a price for weight.

Edited by Klapaucius
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Alright, I took a quick run at this. I just put the Panther on wet mode and gave a plane enough drag to barely fly. There might be a much better solution to this... 

It weighs 22530 at take off and burns 9,778 units of fuel on its flight. 

So that score is 2.30. 

 

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On 5/4/2021 at 2:17 AM, ralanboyle said:

It weighs 22530 at take off and burns 9,778 units of fuel on its flight. So that score is 2.30. 

I love your design. However, you may want to check your units: you burn 9778 kg of fuel, which amounts to 1955.6 units. Each unit of fuel has a mass of 5 kg.

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This seems to me like it'll wind up as a tradeoff of three things:

1) Packing as much fuel as possible relative to dry mass. An idealized aircraft would be nothing but Mk. 0 fuselages, with an 11:1 wet:dry ratio. Incidentally, this caps the minimum score as being 0.0055.

2) Maximizing drag. While there can be some drag from the fuel tanks, wing parts will likely be necessary: any fuel which isn't burned can be replaced by draggier parts.

3) Maintaining lift and controllability throughout the entire flight. This will mean even more parts which are not Mk. 0 fuselages. It also means the aircraft cannot be too draggy, else it'll simply fall out of the air.

Ralanboyle's submission could likely be optimized with a few tricks:

1) Place fuel tanks radially rather than axially. All his fuel tanks were in-line with the cockpit, so their front nodes weren't generating any drag. Egregious part offset shenanigans may be involved. As an example: it might work to place the intake(s) on rear nodes, then rotate and translate them to face forwards again. That leaves the front nodes of whatever they're attached to exposed to drag.

2) Any tanks which aren't burned get replaced by draggier parts.

3) It might be more (in)-efficient to replace the wings-plus-spoilers design with a single surface tilted to have a high angle of attack. This way, one wing part can serve for both lift and drag.

4) Land only at the last possible moment, stopping at the eastmost point of the island runway.

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@QF9E You are correct, my math was wrong...as usual. @Klapaucius, you can do the math on that first effort if you want. Personally, I'd rather just submit a new run rather than do math...

@Starman4308, when doing my new run I went out of my way to not take any of your tips. The gauntlet is hereby thrown down; beat me, I will congratulate you. 

All, I am stuck in a hotel room for a few days. I am both drunk and bored. #pilotlife. 

 

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4 minutes ago, camacju said:

I had a feeling hovering would be the ideal way to go here. I think the only way to beat that score would be to reduce dry mass as much as possible

I bet it's possible to beat my score by around 50% with non-drunk optimization. Also, I bet the multi engine class could get silly. 

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3 hours ago, camacju said:

I had a feeling hovering would be the ideal way to go here. I think the only way to beat that score would be to reduce dry mass as much as possible

In my book, that is basically a VTOL without the takeoff.  It breaks the spirit of the challenge.  I'll let it pass since I did say exploit the rules, but I would be keen to see entries that manage to do it in level flight.

@ralanboyle Did you take your number from KE or from the  resources tab?  If not the latter, your new score is 11.5

Edited by Klapaucius
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@Klapaucius resources. For the second run, I used 840 units, Its the two 400 unit fuel tanks plus the 40 in the static intake. 

On the issue of VTOL/AOA. I'm unsure of the best way to define what you want. All airplanes are going to have an angle of attack while flying. Mine is just stupid high. 

On the issue of VTOL... I mean... It does not have the ability to Take Off or Land Vertically... so...

In defining the spirit of the challenge. You could have a rule regarding the maximum angle of thrust relative to the horizon. It seems a little forced but it would keep people from doing what I did and force people to use horizontal thrust in combination with high AOA wings. Which would be entertaining. 

For those interested in some nerdy aerodynamics; 

Normally the Critical Angle of Attack is the angle at which an airplane stalls (AOA is the angle between the Cord Line of the wing and the direction of flight). Some airplanes can remain stable while above critical AOA (despite what the FAA claims...), this is called High Alpha. My airplane had an AOA of about 80 degrees for most of the flight despite having a Critical AOA of around 30 degrees. 

In aerodynamics much attention is given to the trade off between Horizontal verses Vertical Component Of Lift. But the trade off of Horizontal verses Vertical Component of Thrust is basically never discussed (except by nerds in lab coats). In a nut shell, Vertical Component of Thrust increases with the AOA of the engine. So, with a flat wing or fully symmetric wing in line with the thrust, the Thrust AOA and the Airfoil AOA will be the same. As the Vertical Component of Thrust increases, it makes the plane aerodynamically lighter which decreases the lift requirement. If you are able to increase your Vertical Component of Thrust at a rate sufficient to overcome the loss of lift caused by stalling, then you can maintain stable flight in High Alpha. The smooth transition is the hard part because the curve of lift required is not linear.  

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Alright, alright, alright. No more shannannagans, just a good (crap) old fashioned prop job. No chutes, no high alpha, no silly drag. That big ass turbo shaft eats fuel. She's a big poodle that didn't want to get off the couch, but at the end of the day, she got there. She weighs 20,495kg and used 2,000 units  (10,000 kg) of fuel. 

 

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21 hours ago, ralanboyle said:

Alright, alright, alright. No more shannannagans, just a good (crap) old fashioned prop job. No chutes, no high alpha, no silly drag. That big ass turbo shaft eats fuel. She's a big poodle that didn't want to get off the couch, but at the end of the day, she got there. She weighs 20,495kg and used 2,000 units  (10,000 kg) of fuel. 

 

Oh you think those kind of turboshafts eat a lot of fuel?

There is more than one kind of turboshaft. A single blower assymetric 1 Panther, Rapier, or Goliath ye olde turboshafte? With full stock drag? Yeah that's gonna gobble up a lot of fuel.

For reference, even with a global drag multiplier of 0.1, this thing burned around 300 kg of fuel in a 2150 kg plane flying 60+ m/s. That's with one Juno using aero cheats and trying to minimize fuel consumption. oSzolUq.png

Edited by Pds314
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On 5/3/2021 at 5:17 PM, ralanboyle said:

Alright, I took a quick run at this. I just put the Panther on wet mode and gave a plane enough drag to barely fly. There might be a much better solution to this... 

It weighs 22530 at take off and burns 9,778 units of fuel on its flight. 

So that score is 2.30. 

 

You might wanna recalculate your score.

I think you'll find you are actually burning about 996 units of fuel, not 9778.

AFAIK you're burning about 9800 delta-V. Which suggests 77.9% of the mass reaches the island while 22.1% is spent fuel. I.E. You're burning about 4979 kg of fuel. But as a unit of fuel is 5 kg, So that's more like 996 units of fuel.

Your actual score is 22.6.

Not 2.30. Which would imply that you're burning over twice your starting weight in fuel.

 

Anything with no refueling should always get a score of at least 5.5. Obviously if it ISRUs fuel from the seafloor or whatnot you could actually get 2.3 but yeah I don't see you doing that at any point in the flight.

Edited by Pds314
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Having seen this challenge run for a few days, I realize I did not think it out as well as I should have.  I'll leave part 1 as is, since there are already entries.

 

Part 2 has been opened up a lot.  Hopefully this will generate some truly insane craft.

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