Sepratron Airplane Challenge

Klapaucius · April 16, 2021

This challenge is a direct result of @peridoot's Small Plane Challenge which was a heap of fun to participate in.

The goal: fly as far as you can powered only by Sepratron rocket engines.

RULES:

Stock and DLC only.

You may use any number of Sepratrons, and you can stage their firing however you like, BUT...you have to land with everything you took off with. No dropping parts. I'm very curious to see what the diminishing returns limit is.

You may take off from any of the airfields.

You must take off and land horizontally. You can elect to use landing gear or eschew gear, but you need to land intact. No chutes.

Part clipping is fine except for the engines. Each nozzle must be distinctly visible.

I'd like to measure both time and distance, but I know the F3 is not the most reliable. Any suggestions appreciated.

Your craft needs to have lifting surfaces. You are welcome to use SAS, but your plane should be able to take off without it (in other words, no torquing your way off the ground or maneuvering by torque alone).

Time will be calculated from takeoff until landing. Your gliding time counts towards flight time.

There will be separate leaderboards for autonomous and Kerbaled aircraft.

LEADERBOARD

@ralanboyle 40:25
@swjr-swis KlapSAC-1d 18:30

@camacju 12:31

@Klapaucius "Carlo" 10:30

@vyznev7:40 (water landing--will need to land on the ground to fully qualify)

My entry: 50 seconds aloft.

Edited May 3, 2021 by Klapaucius

camacju · April 16, 2021

Here's a quick submission. Could be improved significantly but this is a pretty good start.

In VAB. Three stages of Sepratron to adjust the thrust profile

On runway

Steep climb

Final stage firing

Apoapsis of 42 km. Not optimal by any means

Pulled into a glide. Ideally I'd do this sooner but Mechjeb wasn't cooperating

Wheels down

Landed at 12min 31sec

vyznev · April 16, 2021

I thought this seemed vaguely familiar…

(It's not quite the same challenge, since that one only allowed one sepratron per craft, but all entries there should qualify for this challenge too. Modulo possible physics changes in three years, at least.)

Klapaucius · April 16, 2021

19 minutes ago, vyznev said:

I thought this seemed vaguely familiar…

(It's not quite the same challenge, since that one only allowed one sepratron per craft, but all entries there should qualify for this challenge too. Modulo possible physics changes in three years, at least.)

I had a feeling there would be something similar in the archives. However, and I may not have been clear enough, but in my challenge you need to take off from a runway like a plane (and it has to have lifting surfaces. The above challenge allowed launch clamps and maneuvering by SAS alone.

Klapaucius · April 16, 2021

1 hour ago, camacju said:

Pulled into a glide. Ideally I'd do this sooner but Mechjeb wasn't cooperating

Wheels down

Landed at 12min 31sec

Cool. However, in looking at it I think it breaks the engine clipping rule. Every nozzle needs to be distinctly visible. It was to prevent squished over-powered small craft. You've got way more engines in your staging list than are visible.

Klapaucius · April 17, 2021

I've got a new entry, and it is actually a pretty respectable aircraft.

https://kerbalx.com/Klapaucius/Carlo-Sepratron-Plane

I managed 10:30 flight time for a distance of 91205.

Here is a flight from the Island Airfield to the KSC, including taxiing.

vyznev · April 18, 2021

Does this count as a valid craft?

Spoiler

This was just a test run to see how far I could get with two sepratrons, and I forgot to take a screenshot of the F3 screen so I only have the flight time (about 7:40; no video, so I might be off by a second or two there too). Anyway, I'm sure this plane can do a lot better with a few more engines.

As you can see from the screenshot, it does take off without SAS, although control is very limited without it due to the lack of a tail fin. And it does sort of take off horizontally, although it must pitch up pretty quickly since it only has grip pads for landing gear.

Klapaucius · April 18, 2021

6 hours ago, vyznev said:

Does this count as a valid craft?

Yes it does! Very cool.

swjr-swis · April 21, 2021

On 4/16/2021 at 9:39 AM, Klapaucius said:

You may take off from any of the airfields.

Note that due to altitude differences, this grants airfields other than the KSC an advantage (higher TWR & Isp from the sepratrons). For those playing without DLC or on pre-1.4 versions, there are no other airfields than KSC to use.

On 4/16/2021 at 9:39 AM, Klapaucius said:

I'd like to measure both time and distance, but I know the F3 is not the most reliable. Any suggestions appreciated.

True. 'Not the most reliable' is an understatement, especially regarding distances. The worst of it is that it's wildly inconsistent, else we could still compare the numbers even if inaccurate. But it will easily and for no apparent reason sometimes show numbers several times what the real distance could possibly be, while doing a practically identical run.

Possible alternative: you could ask for a screenshot of the Map View once the craft is landed/splashed. When focused on the craft, the Info button will show the LAT/LON of its location.

The default KSC runway spawning point is at LAT 0 2' 55" N, LON 74 43' 28" W. Given that one degree is about 10.5km ASL (10.472), the real ground distance covered is relatively easy to calculate from the difference in degrees.

All that aside, here's my initial entry, the KlapSAC-1d (craft file here): 115 sepratrons (as many as can be fit in a 1.25m bay such that every nozzle remains distinctly visible), impelling a kerbal in an Mk1 command pod. Lifting and control surfaces present and used, three-point landing gear provided for safe landings. Chute is present only for heat and drag reasons and is not deployed.

The KlapSAC-1d reaches an altitude of 57.75km, landing 513km (F3 ground distance) -or around 24.05 degrees (LAT/LON difference, ~252km) if you so choose- away from its starting position, after a flight of 18m30s.

Spoiler