KSPlopnik: the E. Julius Edition

"E. Julius" (soonerfrommi) 02/07/2015 at 16:25 • Filed to: KSPlopnik

1

14

Inspired by Wolfezx's KSP posts, I decided to fire it up this morning and try my hand at making a two stage spaceplane. I've done straight SSTOs before, but I was intrigued by the challenge of designing a small spaceplane that could be lifted to a high altitude by a larger conventional aircraft. I haven't bothered installing any mods since I wiped my install for the last update, so this is all just vanilla KSP. I will say I am very impressed with how easy the new design tools make things.

Designing the spaceplane only took me about 20 minutes—not too difficult when your only goal is to get one kerbal into space. All the subsequent development time went to the carrier plane. Making something that could get off the ground wasn't too difficult. 85% of the development time came from applying little tweaks to make it more stable in flight. I'm able to fly the combined craft up to about 22 km on the jet engines before I start risking a flameout, which is plenty high enough to allow the tiny plane to reach orbit.

The real tricky part comes during the separation. I initially had some problems with the two planes colliding, so I fitted the small boosters to the tiny plane to get it clear before they hit each other. That was the easy part. I found that when the small plane separates, this shifts the center of gravity substantially (obvious). This presents a problem, because if the center of thrust is not aligned with the center of gravity, the thrust induces a moment that causes the plane to start somersaulting through the air. If the engines are throttled low enough, the pitching moment is small enough for the stability assistance to mitigate the effect, and only 15–20% throttle is required for stable flight once separated.

Since the CoG shifts so dramatically at separation, the position of the engines has to be a compromise between the two. In order to allow me to use full thrust when launching the spaceplane, I aligned the thrust with the combined CoG. This means that as soon as separation occurs, the larger plane pitches backwards dramatically. I fitted two small boosters to the nose in an attempt to counteract this at the moment of separation, but the main problem is reducing thrust from the main engines. In order to avoid losing too much speed or accelerating in the wrong direction, I have to act pretty quickly with the spaceplane once it separates. This leaves me no time to adequately reduce thrust on the larger plane after separation, and I don't want to just lose the speed anyways by decreasing thrust before separation.

I've toyed around with the idea of cutting the engines right at the moment of separation since they take a little bit to spool down and thus won't interfere with the small plane too much. Combining this with properly configured boosters on the nose should be able to bring the large plane into a stable glide while I take the necessary actions to get the spaceplane into orbit. As it stands I usually still have enough time to recover the large plane from its spin and set it on a path back towards the runway after I get things sorted with the spaceplane, but I'm not really satisfied with "45 seconds of violent spinning" as part of my mission profile.

I'll probably get back to it at some point tomorrow and try and sort everything out. The stock aero in KSP is pretty shitty though, so after I solve this one to my standards I'll probably wipe the save and install a bunch of mods to get back into the career mode. Happy KSPing Oppo!

Funktheduck > E. Julius 02/07/2015 at 16:30

1

I love watching people play this or seeing what people do in this game, but I can't bring myself to buy it. It's too technical for me to just want to have fun with.

45bullets > E. Julius 02/07/2015 at 16:33

0

i have a question:

what will come first: kerbal coming out of green light, or there being an actual space program called "kerbal"

E. Julius > Funktheduck 02/07/2015 at 16:37

1

I would not go so far as to suggest software piracy, but…

E. Julius > 45bullets 02/07/2015 at 16:39

0

All the news outlets are saying the next update will be 1.0. No release date though, so that could be in a year and a half, but it sounds like they've got the features nailed down. Having played since version .17 though, it is unbelievable how much this game has improved. They can keep it in development for as long as they like as far as I'm concerned.

PanchoVilleneuve ST > Funktheduck 02/07/2015 at 16:40

3

The genius of it is how easy it is to learn it by simply experimenting.

Funktheduck > E. Julius 02/07/2015 at 16:42

1

If I wanted to play it I would pay. I have a job and some spare money. I only used to pirate when I was a broke college student.

Funktheduck > PanchoVilleneuve ST 02/07/2015 at 16:44

0

Yeah. I've watched friends play enough to figure it out pretty easily. When I game I either want semi-mindless or puzzle types. Not huge on technical stuff.

For example. I'm not one of those people who do all the number crunching and researching for the best combos in an RPG or something. I just play in a manner that makes me happy.

PanchoVilleneuve ST > Funktheduck 02/07/2015 at 16:45

1

You should be playing Besiege, FYI.

http://store.steampowered.com/app/346010/

E. Julius > Funktheduck 02/07/2015 at 16:46

1

Ah ok, when you said you couldn't bring yourself to buy it I was thinking it had something to do with how much you thought you would enjoy the game vs. how much it cost. As panchovilleneuve said though, it is a whole lot of fun just learning by fucking up, and barring that there are a bunch of great tutorials and videos.

I know what you mean about not pirating stuff though. I used to exclusively pirate games, pretty much from the time I was 10 or so until this past year. Now that I'm doing remote consulting work through the school year though I have more disposable income, and stuff goes on sale so often I might as well pay the the ten bucks or whatever for a legitimate product.

Funktheduck > PanchoVilleneuve ST 02/07/2015 at 16:51

0

I just watched the Leo takes a look video for that. Looks like a lot of fun.

But..... It's windows only and my windows laptop died. Mac only for now.

E. Julius > PanchoVilleneuve ST 02/07/2015 at 17:16

0

Ughhh I just saw this today, but I went over budget on my last trip so I'm trying to cut back on spending for this month. Looks awesome.

45bullets > E. Julius 02/08/2015 at 08:54

0

yeah, but it just seems odd how long kerbal has been in green light.

E. Julius > 45bullets 02/08/2015 at 08:57

0

I wonder how long the average game spends in the early access phase? Certainly I think KSP is an exceptional case given its popularity and uniqueness. Half the early access games are just bullshit Minecraft or 7 Days to Die clones.

45bullets > E. Julius 02/08/2015 at 09:00

0

true, but it seems like it's been that way for ~4 years and that everyones so used to it that nobody really cares that it's in early access at all. and honestly, the only other good game in early access that I've seen is prison architect.