Low-tech STOCK Career Spaceplanes?

[dire]

Hi folks, I don't know if this is possible and I don't have an "entry", but I'm wondering if any of you have created low-tech spaceplanes before getting the last upgrades to the facilities.

Restrictions on the plane:

Must be capable of getting a payload to LKO. Small payloads are OK, large payloads are better. Realistically, 14 tons to orbit given the mass restriction would be fantastic.

Must be capable of returning to the Space Center after deploying its payload.

Doesn't have to be SSTO, but the less you drop the better. SSTO would be ideal. 

Doesn't have to take off on the runway, but c'mon, it's a spaceplane, not a rocket. I've already seen some very impressive SSTO rockets.

No tech that costs more than 300 research to unlock -- that means NO: Rapiers, Whiplash, Aerospike, Ion (on a spaceplane?), shock intake, engine pre-cooler, or quad adapters (although bi-adapters are available and you can make a quad with 3 bi-adapters). That probably means Panther engines.

Not more than 255 parts or 140 tons total weight.

NO Mechjeb or WiseASS. The planes should be human-pilot-able, because hardcore stock  

If you really want me to score them, I will, but I'm honestly just wondering if it's even possible at this point.

 

I am -working- on an entry but it decided to spontaneously fall out of the air at 6km and 600m/s just after the panthers started giving me 174kn thrust.

 

 

And yes, that is two different flights with the wings and engines set up a little differently.

[TheDestroyer111]

Hmm... So, it should be able to carry payload in a cargo bay or something similar? If it doesn't, I can present you my career mode workhorse's several versions. It all begun from the little "Air scout" that I used for medium-range survey contracts. Then, I had to do some suborbital tourist contracts and due to low funds, I decided that my vehicle needed cheap boosters and be possible to partially recover. So, I made my "Suborbital Rocketplane Mk1" It partially utilised the design of the air scout, but was largely remade: It had the same wings, but a different tailfin, canards, a passenger cabin, LFO tank and rocket engine. It used 2 stacked, jettisonable Hammer boosters for the initial boost and a Terrier engine for the rest. I quickly realized that this design has potential, and despite the fact that its landing gear wreck themselves on land landings and I have to land on water (Freaking 1.1 landing gear...), I attached it on top of a bigger rocket with liqiuid propellant, and used it for orbital contracts. It had excess DeltaV, but this allowed a safer reentry. When Mun flyby contracts appeared, I strapped 2 additional boosters to it and used for Mun flyby contracts (It could do a Mun flyby without them, but reentry would be dangerous).

 

[dire]

That looks like a very handy plane! In the example I showed I have a probe in the cargo hold for all those pesky "Take 4 gravimetric readings on the surface of the Mun" missions, but just getting the plane there is an accomplishment.

[mk1980]

I used a few SSTO planes in my last career game prior to unlocking the final R&D, final SPH or final runway upgrade.

they worked ok-ish. get the job done, but nothing spectacular. Panther engines aren't that well suited for SSTO business.

I uploaded 3 images as an album. The first one is just a crew transport with 8 seats, so it's basically about 4 tons of payloads (2 mk2 crew cabins). worked all right. actually a bit over engineered, had almost 600 m/s left in orbit, which is a lot more than you'd need to dock to an LKO space station or something similar.

the 2nd plane was meant as a fuel tanker (the tank in the middle is basically the payload, i think that's about 12.5 tons of fuel?). worked "OK" but it was somewhat unstable with emtpy tanks, so the one time i used it i had to land it *somewhere* (i think about 100km away from KSP).

the last plane was a pure rocket engine design. the little lander thingy you can see in the image is basically a "mun ferry" that gets 4 tourists to the mun surface and back. the ferry is about 10-12 tons i think, so i guess that's fairly close to your ideal 14 ton payload.

the dual skipper plane worked better than the 8 panthers + 1 skipper plane. my conclusion is that you're better off only using panthers for light duty. they are just too weak to get a usefuel payload to orbit. the rocket plane worked surprisingly well, though.

 

[dire]

That is a pretty cool rocket plane. Do you just point it straight up when you launch or do you do the whole spaceplane "500km run at 10km height" thing to get your speed up first?

 

[mk1980]

i think the thrust/weight ratio of that plane is < 1 at takeoff (otherwise it would be a bit pointless to even launch it as a plane - might as well cut the wings and just launch it as a vertical rocket). i think i pulled up more steeply than a "conventional" airbreathing jet, since the rocket engines don't have that "weak thrust at low speeds" mechanic and actually get more efficient at higher altitudes.

i don't remember the exact ascent (has been a while) but probably something like a 20° climb initially when TWR is still too low for a steeper angle and gradually pulling up towards 45° or something as the TWR rises. i think i didn't go above 45° angle.

or in other words - once you're up around 10km or something, it's not much different from a vertically launched rocket - the difference is just that the vertical launched rocket drops the angle from 90° at liftoff to about 45° while ascending from sea level to ~10km altitude, and the rocketplane raises the angle from maybe 20° at takeoff to about 45° in the same time. after that point, you'll pretty much follow something similar to your standard gravity turn to minimize gravity losses etc.

it's actually easier than a jet plane since you can ignore the "low speed->low thrust" mechanic. and it's actually also a bit easier than a verticalrocket, since you are in no danger of flipping over.

it's just an intermediate design, of course. once you have access to whiplash ramjets, you can easily lift significantly larger payloads with a similarly sized plane. but the rocket propulsion is quite competitive compared to panther powered jet hybrd planes.

[GoSlash27]

dire,

 I design 2 basic spaceplane types: Crew transports and fuel tankers. Crew transports handle around 5 kerbals per trip because I rarely have the need to move more than that. This makes crew transports small, compact affairs.

 Tankers, OTOH... I like them to be as big as I can make them while still have them manageable for landing.

Here's some design idea (all have flown missions)

Best,
-Slashy

[Mesklin]

See my touristic SSTO - 2 tourists to Kerbin orbit and back

https://kerbalx.com/Mesklin/SSTO-Panther-LT-112

 

[*MajorTom*]

my lo-tech ssto

1. I just dont know why this SSTO need for - maybe crew report in different coordinates

2. sat-launcher

3. Mun (Minmus) rover -launcher

2 and 3 craft save you can find here http://kerbalspace.ru/sandbox/saves/other/5040-letaem-na-panterah.html

take-off at 2/3 engine power

Edited July 15, 2016 by *MajorTom*

[TheDestroyer111]

@Parkaboy's SSTO in chapter 9 here:

http://forum.kerbalspaceprogram.com/index.php?/topic/137289-demum-perveniemus-a-stock-career-report-webcomic-chapter-9-online/&page=3

 

[foamyesque]

Ah damnit, I thought I had one but I was going through the parts list and I found out I had one thing that wasn't 300 tech or below:

 

The probe core.

 

[TheDestroyer111]

On 7/17/2016 at 9:44 AM, foamyesque said:

Ah damnit, I thought I had one but I was going through the parts list and I found out I had one thing that wasn't 300 tech or below:

 

The probe core.

 

Emm... There are several of them below 300 tech?

If you mean that no fair sized probe core is under 300 tech, then you may have to redefine your meaning of "fair sized" by using C7 Aerospace's brand new NCS Adapter!

Or just but it into a cargo/service bay.

[foamyesque]

1 hour ago, TheDestroyer111 said:

Emm... There are several of them below 300 tech?

If you mean that no fair sized probe core is under 300 tech, then you may have to redefine your meaning of "fair sized" by using C7 Aerospace's brand new NCS Adapter!

Or just but it into a cargo/service bay.

 

No, I mean I'd built one where every part was, I thought, under the limit, but I forgot to check the RGU. Putting a lower-tech one in the bay instead of at the nose was my planned tweak, yes.