Small Falcon 9 Challenge

[Human Person]

I've seen a lot of Falcon 9 builds but most of them use the 3.75m diameter and Vector engines. I think that's OP for a Falcon 9 as the actual real-life rocket has a diameter of only 3.7m. Also while the Merlin engine has a pretty high TWR, it's actually neither very powerful nor very efficient.

so I want you guys to think small, build it in the 2.5 m diameter or smaller.

Also, the engines used on the first and second stage should be roughly the same thrust. Merlin-Vac can be a little more powerful and more efficient but it shouldn't be too much difference so I decided to give you a list of possible combinations.

All landings have to be demonstrated once, just make sure to lock the fuel you need for boost back and landing.

Size: diameter, 1st stage engines, 2nd stage engine

XS: 1.25m, Twitch/Spark, Spark

S: 1.25m, Cub, Terrier

M: 1.875m, Thud, Cheetah

L: 2.5m, Swivel/Reliant, Skiff or Poodle

 

Things to do: 

+10P Build a scaled down Dragon 2 Spacecraft that is able to land on parachutes. it has to be the same diameter as your rocket.

+5P your dragon capsule has powerful superdraco engines and can use them for a launch Abort.

+5P your dragon spacecraft has a trunk to carry some unpressurized cargo (any cargo will do). also it has solar panels, either the foldable ones of dragon one or the wraparound panels on the dragon 2 trunk. it also acts as an aerodynamic stabilizer for an abort. you can eject the cargo in this case.

+2P a launch abort can throw the capsule far enough for it to parachute land in the ocean.

+3P the spacecraft has RCS thrusters and is able to dock to a station.

now for the rocket:

+50P Build a Falcon 9. It needs to have 9 1st- and 1 2nd stage engines. first and 2nd stage need to be the same diameter, you can use nosecone parts as radial engine mounts on the first stage (a 3x3 engine pattern is allowed as well as the modern circular arrangement). Angling the engines slightly to make them fit is fine as well. Part clipping is allowed as long as it looks nice (try not to clip engine bells into each other)

+20P the 1st stage is recoverable. A splashdown is sufficient, as long as nothing breaks off during tip-over.

+13P  It lands on engine power, no parachutes.

+10P it is able to ddo a boostback and land on or around KSC ground (the entire flat area surrounding the KSC is fine). Now, If you do a landing at sea, you are allowed to tip over and break something. let's just imagine you had placed a drone-ship exactly where you came down and landed on your legs.

+5P  you do the landing burn with only 3 engines. 

+2P  the upper stage has its own probe core and antenna in order to deorbit itself after payload separation.

not done yet, we need to go heavy.

+2P Build a Falcon Heavy. the boosters need to be identical to the core stage except for some sepratrons and struts.

+10P  don't use fuel crossfeed. you may throttle back the core engines or shut up to 6 of them off in order to save fuel. don't forget to throttle back up/ toggle the engines back on at booster sep.

+10P the boosters are recoverable (boostback and landing near KSC is required now). The core can land at sea.

+3P the core stage is able to land on the next continent. 

 

Please keep it stock (+ Making History) and share your craftfiles. I'd really like to make a livestream of some sort and look at all of them personally.

 

Coming next: missions for our Falcons. I'm planning to make a TESS mission as well as a Mun landing using Falcon heavy's and perhaps a LKO station.

 

Please share videos or pictures with your mission report, but make sure to put all but one picture in spoiler. or share an imgur link, as there's nothing worse than huge post with unbelievably many pictures who are all getting loaded. keep it simple.

 

Have Fun!

 

 

 

Edited September 30, 2018 by Human Person

[Kerbalstar]

Looks great, will try @Human Person!

[l0kki]

I decided to go XXS and build one with 0.625m parts,

Craft files:

Normal: https://kerbalx.com/l0kki/Mini-falcon-9 Heavy: https://kerbalx.com/l0kki/Mini-falcon-9-heavy

I also recorded this video with the normal one.

 

[Human Person]

@l0kki I like miniturization and it's a darn fine little rocket you got there but you can't put crew on it  ... or can you? I will definitely try in my livestream.

If it's too small for crew or any reusability, it's more like an Electron rocket, still a nifty little thing. I"m especially curious about the capabilities of the heavy variant. 

 

As for my own rocket, I have an L and an M variant (i'm starting to like the M one better) and I'm currently editing a video about it. It's my first ever youtube video and I want it do be good with "back to old me" parts and such.

Edited September 29, 2018 by Human Person

[l0kki]

16 minutes ago, Human Person said:

@l0kki I like miniturization and it's a darn fine little rocket you got there but you can't put crew on it  ... or can you?

Is that a challenge i see??????????????????????????????????????????????????????????????????????

Btw i tried reusability but ksp hates parachutes that arent on your vessel

Edited September 29, 2018 by l0kki

[James M]

Totally doing this. 

[l0kki]

So i made it to orbit with this version of the mini falcon 9 heavy, the normal one seems to be too weak to make it to orbit with this crew capsule, i challenge you @Human Person to do it with the mini falcon 9

Craft file: https://kerbalx.com/l0kki/Mini-falcon-9-heavy-crewed

[sturmhauke]

Are there rules about the abort engines? Like, could I just stack some sepratrons on there?

[Human Person]

On 10/3/2018 at 1:08 AM, sturmhauke said:

Are there rules about the abort engines? Like, could I just stack some sepratrons on there?

Hmm, I would say no, go ahead, but I strongly recommend using liquid engines as they can be used also for orbital maneuvers as well as for propulsive landing.

Edited October 7, 2018 by Human Person

[Kernel Kraken]

Ooh, I love the twitch engines. Spam them and they'll be an efficient mammoth substitute. Definitely gonna try this!

[Human Person]

4 hours ago, Kernel Kraken said:

Ooh, I love the twitch engines. Spam them and they'll be an efficient mammoth substitute. Definitely gonna try this!

lol, looking forward to see it.

I'm sorry for taking so much time with the video on my entry. I want to make it pretty, so far I only have 30 min of raw footage with live commentary. maybe I'll just upload that

 

 

[eagle92lightning]

On 9/27/2018 at 2:49 PM, Human Person said:

you do the landing burn with only 3 engines.

The IRL Falcon 9 usually uses only 1 Merlin 1C or Merlin 1D. The three engine technique is not fully developed yet.

[linuxgurugamer]

14 minutes ago, eagle92lightning said:

The IRL Falcon 9 usually uses only 1 Merlin 1C or Merlin 1D. The three engine technique is not fully developed yet.

Actually, the Falcon 9 uses 3 engines for landing

[eagle92lightning]

32 minutes ago, linuxgurugamer said:

Actually, the Falcon 9 uses 3 engines for landing

No, for the entry burn the center engine stays lit and the outer eight cut on and off in pairs in of two.
 

And this is a droneship landing burn (the higher velocity of the two landings) as seen from the bottom of the Falcon 9.

 

This is what a three engine landing burn looks like, compare the diameters.

Edited November 24, 2018 by eagle92lightning

[vyznev]

Well, I made a 2.5 m scale Falcon Heavy back in January, so I figured I could just rebuild a single-core version of it for this challenge.

Actually, I already did this last month and posted screenshots of it in another thread, but I forgot to post it here too. So here it is now. Better late than never, I guess. 

Anyway, I believe this meets the following targets:

On 9/27/2018 at 9:49 PM, Human Person said:

+10P Build a scaled down Dragon 2 Spacecraft that is able to land on parachutes. it has to be the same diameter as your rocket.

+50P Build a Falcon 9. It needs to have 9 1st- and 1 2nd stage engines. first and 2nd stage need to be the same diameter, you can use nosecone parts as radial engine mounts on the first stage (a 3x3 engine pattern is allowed as well as the modern circular arrangement). Angling the engines slightly to make them fit is fine as well. Part clipping is allowed as long as it looks nice (try not to clip engine bells into each other)

+20P the 1st stage is recoverable. A splashdown is sufficient, as long as nothing breaks off during tip-over.

+13P  It lands on engine power, no parachutes.

It might also be able to do a boostback RTLS and still make orbit, but I haven't actually tested this, so I won't count it.

Honestly, looking at this craft and the target list now, I see several potential ways to improve it. For one thing, the first stage is kind of short and stubby compared to the real Falcon 9, and could probably easily accommodate one more fuel tank. Also, the second stage was just something I quickly slapped together, and I could easily improve it for more points. And of course I could always turn it back into a three core heavy variant like I flew back in January.

Still, at least it flies (and lands). 

Here's the craft file: https://pastebin.com/Kz2yJduX

And here are a few more screenshots of the test flight (including a bunch of failed landing attempts): https://imgur.com/a/A1mt0Ik

I do also have video of the flight, but I still haven't gotten around to actually editing it. Maybe later...  

[JacobTheFoxx]

Has anybody made a badge for this challenge? I might attempt it and I could make a badge if you're interested. My skills aren't great, but'll do.

[Human Person]

@vyznev nicely done! actually landing on a drone ship is a nice touch, haven't managed to do that myself (also I didn't try very hard).

On 11/24/2018 at 11:00 PM, JacobTheFoxx said:

Has anybody made a badge for this challenge? I might attempt it and I could make a badge if you're interested. My skills aren't great, but'll do.

of course you can make a badge if you like. 

On 11/24/2018 at 8:37 PM, linuxgurugamer said:

Actually, the Falcon 9 uses 3 engines for landing

this is what they tried to do on the Falcon heavy core Stage landing. AFAIK this was the only attempt so far on a landing where 3 engines stay lit until touchdown. Usually, they do what eagle92lightning said:

On 11/24/2018 at 9:06 PM, eagle92lightning said:

No, for the entry burn the center engine stays lit and the outer eight cut on and off in pairs in of two.

but they actually use all 3 engines on the landing burn, it's just that the 2 outer engines cut off prematurely so final touchdown can be done more precisely on just the center engine.

[eagle92lightning]

57 minutes ago, Human Person said:

but they actually use all 3 engines on the landing burn, it's just that the 2 outer engines cut off prematurely so final touchdown can be done more precisely on just the center engine.

If you would have read all of my posts, that is partially correct, SpaceX has even said that they only have 1 lit at the moment of touchdown. Yes they have landed them with all three lit and the majority of the time they only light the center one.