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Dessert Airfield Race on Fumes


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The aim of this challenge is to reach the Dessert airfield as fast as possible with a limited fuel budget. Time will be based on the ingame mission timer, and stops when you are on the Dessert Airfield runway at less than 1.0 m/s.

 

Craft Restrictions

1. No source of electricity generation besides engine alternators is allowed. Any batteries on the craft including cockpit batteries must start empty. Feel free to use power generated by alternators however you desire. No resources besides LF should be on the craft at launch. ISRU is prohibited.

2. No free energy devices.

3. Breaking Ground props must be node attached and not offset.

4. No aero exploits. Including magic wings or node abuse.

5. Offsetting parts is legal but they should be in visual contact with the part they are physically attached to.

6. Keep clipping realistically justifiable.

7. Craft must have an aircraft-grade cockpit with a pilot. Not a probe core, command chair, or space capsule.

8. Craft must survive in airworthy condition. That means it can take off again if refueled.

 

Categories

Full Throttle: craft may have up to 200 u of LF.

1. Camacju 8:26
2. Ralanboyle 9:54

Reserve Fuel: craft may have up to 75 u of LF.

1. Camacju 10:07
2. Ralanboyle 10:22 (presumptive).

Droplets: craft may have up to 25 u of LF.

1. Ralanboyle 21:50

Vapors: craft may have up to 10 u of LF.

Edited by Pds314
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Here's my submission for full throttle mode at 8:36. Single rapier powered plane that uses the full 200 liters of allowed fuel.

U5T4J6c.png

Launch. 4705 kg mass, single rapier powered

hiVMbuA.png

Cruise at 12 km. The ideal efficiency regime of the Rapier is such that it's at full throttle and still at the edge of flameout. That means that there's usually an optimal altitude to fly the Rapier at - the lower the drag the lower the altitude.

0BVjCEG.png

Death dive toward dessert airfield, trying to scrub off velocity

c9AYkQy.png

Approach

dNpc1Wh.png

Landed - I overshot the runway a bit but it never said I had to land there, just reach it, and I definitely reached that far

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5 hours ago, ralanboyle said:

Okay yeah. 

Reserve Fuel run took a little longer cause I couldn't leave it balls to the wall. 10:22. Apparently Youtube doesn't want to imbed this one- https://youtu.be/ZcRbSjJ4UoE

The video for this one is private. I'm gonna assume you intended it to be public rather than engaging in some kind of elaborate shenanigans and add it to the scoreboard.

4 hours ago, camacju said:

Here's my submission for full throttle mode at 8:36. Single rapier powered plane that uses the full 200 liters of allowed fuel.

U5T4J6c.png

Launch. 4705 kg mass, single rapier powered

hiVMbuA.png

Cruise at 12 km. The ideal efficiency regime of the Rapier is such that it's at full throttle and still at the edge of flameout. That means that there's usually an optimal altitude to fly the Rapier at - the lower the drag the lower the altitude.

0BVjCEG.png

Death dive toward dessert airfield, trying to scrub off velocity

c9AYkQy.png

Approach

dNpc1Wh.png

Landed - I overshot the runway a bit but it never said I had to land there, just reach it, and I definitely reached that far

Nice! I like the design but unfortunately it's not really a valid run unless you wanna waste precious seconds taxiing back to the runway.

" Time will be based on the ingame mission timer, and stops when you are on the Dessert Airfield runway at less than 1.0 m/s." -second sentence in the OP

Wow I did not expect RAPIER entries to be viable at 200  LF.

One other thing... Engines clipped into fairing to have zero drag but still generate thrust because they're clipped outside the fairing seems a bit beyond "realistically justifiable clipping." Unless you have a good justification for it I'm gonna go ahead and say that is an invalid design.

Edited by Pds314
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@Pds314 I redid the craft to not be clipped and also to target the runway. Shaved off a few seconds also

ISQTV9Z.png

In SPH, 200 fuel load

TYXsDnn.png

Takeoff

H2Hj8vq.png

The craft can cruise at 2 km/s but it guzzles fuel. It uses way less fuel at a cruise speed of 1750 and altitude of 10 km, so I go at 2 km/s for a while and then climb to 10 km.

BMOmxVY.png

This is what happens if I try to go at 2 km/s the whole way - I run out of fuel over the desert

FVLG9bO.png

Meanwhile at 1750 m/s and 10 km, I have a lot of fuel remaining while I line up for the Dessert Runway

xXvJqSX.png

Landed at 8:26

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@Pds314 I got to the airfield on 25u without too much trouble, but making a plane that could also land took 2 days. Even then it took a dozen tries to get her on the ground. For your entertainment, I didn't cut out the crashes. 22 minutes. 

 

Edited by ralanboyle
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7 minutes ago, ralanboyle said:

@Pds314 I got to the airfield on 25u without too much trouble, but making a plane that could also land took 2 days. Even then it took a dozen tries to get her on the ground. For your entertainment, I didn't cut out the crashes. 22 minutes. 

 

Wow I wonder why it was so averse to landing? 21:50 is an amazing time for that category though.

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Just now, Pds314 said:

I wonder why it was so averse to landing?

I don't know. First I had this same ship as a tricycle and tried maybe 50 times. All wheel settings and VERY gentle landings. No bueno. Then I tried it as a tail dragger. Same deal. Hence, quadracycle. After 3000+ hours of KSP, I've never had this much trouble landing a small plane. 

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On 5/21/2021 at 2:57 AM, Pds314 said:

Wow I did not expect RAPIER entries to be viable at 200  LF.

How about 75 LF?

The main reason I think Rapiers are viable is that they have a more favorable mach and pressure vs thrust curve than other jet engines, which means that even though they're less efficient they can be competitive at a higher speed.

5wPp4SP.png

Very similar plane but less fuel initially loaded. Only 70 fuel

xRdt0Uo.png

Steep climb to cruise altitude. Could have done this significantly better - I had the throttle open too long and went up to 50 km before pulling out of the dive at 14 km. Way inefficient + slow

aKtB5nr.png

At 24 km and 1700 m/s the rapier flames out a lot so I throttle back to maintain even thrust.

A6LIDNO.png

I should have started my dive earlier. Approaching airfield

TrAAM6J.png

Landed at 10:07. i bet I could shave a full minute off this time

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