KevinTMC's Delta Hornet: Basic jet aircraft...with optional rocket delivery!

[KevinTMC]

I had sent Jeb off to explore a polar anomaly on Kerbin...only his craft landed without any return fuel, and also he managed to crash the rover before getting even remotely close to the anomaly. Rescue time!

I built this jet to go fetch him before his maniacal smile was permanently frozen into place by the arctic cold. Looking at the finished product, I'm not sure whether I did much more than re-invent one of the Ravenspears--but I did build it from scratch.

Or rather, it grew out of two other designs: a tiny uncontrollable thing that I had called the "Hornet", and a classic delta-wing jet that I had--even more imaginatively--called the "Delta". Combine the two, and you've got the Delta Hornet, the most flyable atmospheric craft I've ever devised (a very, very low bar to clear, admittedly):

Delta Hornet: 10.989Mg, 44 parts

Operational ceiling: approx. 20,000m

Cruising speed: approx. 445m/s at 12,000m

Operational range: approx. 990km

At cruising altitude, this craft handles 2x physical acceleration smoothly. 3x is often quite tolerable; and even 4x will often prove a non-catastrophic choice in short bursts.

The Delta Hornet comes with not one, but two patented Rescue Seats mounted behind the cockpit! Here's one satisfied customer, testing out a Rescue Seat and having a whale of a time:

This jet proved perfectly capable of reaching Jeb...but not of making it back home. It needed more range.

And possibly more explosions.

And so, in the following post I introduce...the Delta Hornet, Rocket-Launched Edition!

[KevinTMC]

What was needed for the polar rescue mission, to go fetch Jeb (and now also Bill, who had flown out in a standard Delta Hornet which was barely sufficient for the outward leg of the trip) was something with greater range, more excessive cost, and more potential for catastrophic failure. All three requirements were met in the Delta Hornet, Rocket-Launched Edition (or Delta Hornet RL):

Delta Hornet RL: 345.485Mg, 308 parts with launcher; 10.993Mg, 48 parts plane only

Delivery range (ground-to-ground, without using jet engines): approx. 1080km

Launch profile: Retract landing gear. Set throttle to three ticks below maximum (as high as it can go without making the Mainsails explode) for launch.

At about 8000 meters (as it's starting to get squirrely), throttle down a couple more ticks to the 2/3 mark, turn on RCS, and begin gravity turn, carefully pitching down to about 50 degrees. There's an excessive supply of monopropellant, and this thing can be hard to steer, so go ahead and leave RCS on as you try to maintain pitch and heading until apokerb reaches about 100km.

Cut main engines, and pitch down to the horizon. There should still be tons of monopropellant left; at this point, I keep the RCS on and thrusting forward, and manually steer with ASAS off so more of the RCS thrust goes into forward motion. (This may only earn me a couple extra kilometers, but it burns excess fuel...and everyone needs a hobby of some sort, I suppose.)

At apokerb, burn whatever fuel is left in the main tanks. I use up the remaining RCS as well, to get just a little more distance out of the suborbital flight. Then it's time to stage.

On those days when KSC safety officers are actually invited to mission-planning meetings, they highly recommend staging with the craft pointed prograde, and before gravity starts to kick back in.

If lights are on, you might want to turn them off to save electricity. Enjoy the glide back down.

Once you're back in the thicker parts of the atmosphere, it will take some effort to keep the nose up; use lots and lots of trim to help. Leave jet engines off until under 15,000m; once they're fired up, you should be able to wrestle the plane into normal level flight before it dips below 10,000m.

Or you can leave the engines off and glide to a landing. Harbas Kerman did just that; here he is, safely landed 1080km east of KSC with full jet fuel:

[KevinTMC]

Craft files are available here:

Delta Hornet (Stock)

Delta Hornet RL (Stock)

Action groups for Delta Hornet:

Abort) Toggle engines and landing gear; deploy chutes

1) Toggle ladders

Action groups for Delta Hornet RL:

Abort) Decouple all; fire all sepratrons; shutdown rocket engines; toggle jet engines; toggle landing gear

1) Toggle ladders

0) Abort Mode 2: Deploy chutes

[Rune]

You lacked range? That should be capable of circumnavigating kerbin with that much fuel! The problem is that you are likely staying too low because you don't have enough intakes to fly at <20kms and <1,000m/s. That's how you cross continents. Seriously, I have gotten to the north pole and back with a single fuel tank and engine by airhogging at <1500m/s.

Rune. Other than that, so kerbal you might want to ignore my comment

[KevinTMC]

Ah. Just goes to show how much I've still got to learn about jet engines and atmospheric flight and such.

Would it really help extend the range that much by just adding some intakes to the design and flying higher (we're talking what, 25km instead of 12?)...or would I need to also switch from the Basic Jet Engine to Turbojets?

I used the Basic Jet exclusively here, since there were only two engine slots and I was designing it for lower-altitude flight; but perhaps I wildly overestimated the limitations of the Turbojet? If two Turbojets on this plane would be only moderately worse for flight below 10,000m, while they raised the ceiling and allowed vastly more efficient flight at a high cruising altitude, then switching to those would be rather a no-brainer (though I'm not sure why one would ever choose the Basic Jets, in that case).