Just wanted to share an abomination...

[Matrazuchi]

So, I'm a n00b, that's a given... and my KSP exporation is at the beginning, but that's no reason to have it dull. So, here's what I try to do: I'm selecting contracts that could be somehow done together in the same flight. Is not always efficient, but it's a challenge.

I would like to share with you one of those combo-contracts and the craft which made it possible:

My latest challenge was composed of two contracts:
- get two tourists on a suborbital trip (their faces when the craft took off, just priceless )
- test J-33 "Wheelsey" turbofan at 2000-4000m altitude, and a speed between 170 to 250m/s

... Anyway, the two seemed somehow contradictory at a first look, as one required a rocket, the other one an airplane. Why not do a rocketplane then, and solve them both? And as long as we're there, why not add some extra scientists and a bunch of instruments, and collect some science and crew reports while at it?
Suffices to say that it took me a bit of experimentation, as I went from cheap and simple to complex and expensive... and at first i barely reached 16000m, then somehow I made to 20000, and then, when I reached 60000, I though that was the limit and I won't be able to pass 70000, but that was just my self-doubting.  Eventually I got there, landed the scared passengers safely and without making them sick (yep, it was among the requirements)... but, not the entire plane landed.

As you'll see in the images below, the craft is meant to lose its parts as it goes, it's loaded with decouplers, the first ones to go being the landing gears (who needs landing gear anyway? ). And descending from suborbital, on a very steep trajectory wasn't too much fun either, as I had a very narrow window for deploying the Drogue chutes, good thing I got redundant on those (had 4, two of which were blown away by the overheating and speed, but they slowed the craft just enough for the other two to deploy and do their job... from there, it was all routine).

The way it happened:
1 - took off using the wing jet engines (all engines had 10% fuel only)
2 - short after taking off, lose landing gear (was fitted on decouplers, like most parts)
3 - get temperature measurements, as accelerating towards the first contract, with all those nipples under the belly (turns out one can get all measurements one wants, in a place, as long as enough instruments are brought along, and they all count equally)
4 - kick in the "Wheelsey" engines, those surely made a difference, despite the small air intake fitted on.
5 - get the liquid fuel rocket on (preset at 70% thrust), this happened at around 10000m, as the vertical speed was dropping under 100m/s, and that made the jet engine viable until just under 20000m, when they flameout.
6 - not long after, I dropped the wings, as they would only cause drag
7 - once the jet engines flamed out, I dropped them all and boosted the rocket engine to 100% (still keeping the canards, will need them later). From here, is just a rocket with canards...
8 - for the descent, I still happened to have a bit of fuel, which I used to slightly reduce the descent speed just before hitting thicker atmosphere, it didn't do much, but it helped to open the chutes before getting all fried.
9 - dropped the rocket engine and tanks and now it's only a glorified capsule (poor tourists, only if they knew how little was standing between being crushed to death and living to tell)
10 - deployed the drogue chutes, which didn't pop until the atmospheric thickness became viable (just at the same time when air friction was starting to cause plasma), the first two failed immediately, but they allowed the other two to just make it... 
11 - dropped the canards, as now they had no purpose, dropped the heat shield at the back of passengers compartment (yes, i had one, where the liquid fuel was attached)
12 - deployed the main parachutes and landed safely, taking those poor stand-up guys money... plus a lot of science that I got to collect.

Would you have it done differently?

 

Edited November 10, 2022 by Matrazuchi

[DeadJohn]

48 minutes ago, Matrazuchi said:

Would you have it done differently?

You didn't do anything wrong, just commenting on what I might have done.

Mismatched part sizes cause extra drag. I would use larger intakes on the Wheesly engines even if I didn't need the extra airflow. Maybe you didn't have them unlocked in the tech tree yet.

I might have tried a vertical rocket instead of a plane for a less complex ascent. No wings, no landing gear. Keep the central core of your ship with the capsule + crew cabin + LFO rocket. Maybe add more LFO if needed. Remove all the Juno engines and canards but keep the 4 rear fins for control. Reposition the 2 Wheeslys so they are balanced on opposite sides of the central core. The Wheeslys are mostly along for the ride, only slightly boosting thrust during the early part of your flight, then stage them away when you are flying too high and too fast for them to do anything.

 

[Matrazuchi]

1 hour ago, DeadJohn said:

Maybe you didn't have them unlocked in the tech tree yet.

Correct, even the "Wheelsey"  I don't have it yet. It was temporarily available for the contract, So I had to improvise.
 

1 hour ago, DeadJohn said:

I might have tried a vertical rocket instead of a plane for a less complex ascent. No wings, no landing gear. 

It could work, if the rocket had a very low ascension rate, so its speed would be under 250m/s until it goes past 4000m, for the engine test contract. But then, if I did that, I wouldn't have anything to share with you guys 

[darthgently]

I've used air breathers as a first stage.  It takes a lot of them and you want to keep the clamps engaged until they are completely spooled up.   On a vertical ascent, they start wheezing fairly soon into the flight