Kerbalife Security Export SSTOs

[PolecatEZ]

Hello and welcome to my historical presentation of Kerbalife Security products. At Kerbalife, we're dedicated to giving you only the purest products with our natural all-stock guarantee. Our organic design methods keep clipping to a bare minimum while while still giving you the aesthetic appeal of stucco wall paper. If you need any specifics about a model, or would like to become a Kerbalife Independent Designer yourself, let us know after the presentation. Thank you for sitting through our Kerbalife presentation. On with the show...

AA-10E Angry Bird

The Angry Bird Project, or the more affectionately known "Plucked Chicken Project" came as a result of the first attempts at SSTO design by the engineers at Kerbalife Security. Mainly, they sucked...badly. After the 14th test pilot went down in a high-altitude flat spin of flames, Kerbalife executives sent out a procurement order for off-the-shelf systems in a competitive bid. After months of expos and airshow attendances, 12 shiny new KF-X Sparrows were purchased. At first the pilots loved them because, well, they didn't kill them outright. However, attempts to use the KF-X for delivery of small space objects sometimes left the pilots with very little delta-V for the return trip, especially with slightly larger masses or higher orbital targets. After confering with higher-ups, the engineers began tearing them apart to find out what made them tick.

The requirements for the improved Sparrow, dubbed the Angry Bird, were for use of atomic engines, the ability to take at least 1 ton of cargo into 120km orbit, and use entirely oxidized fuel. Hidden parts were also stripped out, including the faulty mono-propellant tanks, and the troublesome neck-docking clamp was removed for a more conventional piece after an early model disassembled itself in orbit. The current model can put a dual-loaded cargo load into 100km orbit with about 1000 delta-V to spare, and can also refuel for a full 3200 delta-V at any LKO station.

AA-40C Cobra

The Cobra is the bastard step-child of the mildly successful AA-39 Pythagorus flying triangle and the abortive AA-03 Mouser III design responsible for the deaths of 8 brave test pilots. Following the success of the Angry Bird project, engineers went about trying to figure out, "How freaking big can we make these things?" The results got into orbit on the very first test flight. Featuring 3 ramjet engines with ordered flameout, as well as dual-atomics, the test pilot basically said, "I made 1500 m/s easy, then just shot skyward and profit!" Later refinements added successful "Muner landing gear" to the backside, where a vertical landing is possible, then a simple drop will put it back horizontal as well as large solar panelling just because it looked cool.

Featured above is a joint Manta Class Carrier and Cobra SSTO project where engineers literally attempted to mate the two designs. The Hammerhead Class frigate was born a few months later...

AA-20B Mighty Mouse

The Mighty Mouse is the SSTO conversion of the Mouser VII conventional attack fighter. The conversion was conceived and performed as part of an off-handed bet between Billy-Bobias and Sidson Kerbal over whether 2-1 rocket-jet combo was more efficient than a 1-2 rocket-jet combo. The result was a powerhouse re-dubbed the Mighty Mouse. Its efficient design allowed it to take 2 kerbals into LKO with still about 2500 delta-v to spare without a refuel.

The Kerbalife executive board was split between putting the Mighty Mouse into full fleet production or holding out for "something that didn't look like a *** ***." The aesthetics fans wanted a rework of the Sparrow design instead. After about 2 weeks of virtual war in the boardroom, a compromise was made wherein the new engine layout would be a 2-2. The Mighty Mouse models in service were relegated to trainer status and the Eagle was born.

AA-31C Eagle

After about 10 iterations, the board finally approved the AA-31A Mighty Eagle (later shortened to Eagle) for the primary production run. In addition to pushing a metaphor, the wings proved surprisingly stable and powerful, as well as the somewhat tricky but optimal engine layout. The result is a production work horse capable of putting 4 tons of distributed payload into LKO with 2000 delta-V to spare. Later models added the Munar landing struts as well as other avionics and wing-layout optimizations.

So far, almost 150 have been produced, with another 80 currently being made for export. Only 2 have been lost to accidents or structural failures, one of them taking out Fuel Depot Yankee in a spectacular lesson in how not to dock.

AA-32D Condor and AA-30B Falcon

Following the start of production for the AA-31 Eagle series, several variants were produced which culminated in the AA-32D Condor for almost exclusive use by Kerbalife Security Marine Division. This model features a fighter cockpit upgrade for the front end, as well as extened and expanded wingspan allowing it a much better (and slower) angle of attack vector for unleashing up to 12 tons of ordnance on a target, either diving in from orbit or by more conventional runway to target missions.

The AA-30B Falcon, on the other hand, is a major retrofit for the AA-10 Angry Bird/Super Sparrow series to attempt to bring it up to the Eagle standard. It features the changed wing design and a longer centerline fuel tank, but otherwise doesn't change the profile of the AA-10 significantly.

And now for something completely different...

DS-05E Confederate Skycrane

Hot on the heels of the success of the DS-02 Union and DS-3 Overlord Dropship designs, engineer Sidson Kerbal decided to slap a few rebellious jet engines onto the side of a DS-02 Union "just to see what would happen." The dumbfounded mission control team then watched as it made orbit on its very first run. Given that 30 tons just made it into orbit without losing any stages, it suddenly found itself in the SSTO category. After some tinkering with the original retrofit, the "lander can" cockpit was added, the 3-man was dropped in favor of cargo, and the engines were placed outward from the body so as to accomodate odd-sized underslung loads. The result can put up to 5 tons into LKO with just enough delta-V to de-orbit and do a controlled parachute/VTOL landing right back at KSC.

For best results, plug in the numbers above into your favorite ascent computer, kick on the atomics at 30,000m, turn off the jets at 36,000, and you should be home free as long as you're keeping the throttle at safe jet levels. Landings do need some jet assistance, as the chutes will get it to 10 m/s or so, jets will be needed to get it down to < 5 m/s.

In the future, we will be posting up threads of Dropships, Capital Ships, and our very own line of Space Station parts.

Cheers,

Polegato Kerbal, Kerbalife Independent Designer

Addendum - Basic SSTO instructions:

As for flight profile, testing these gave me some very hardcore experience (probably spent easily 100 hours getting spaceplanes into orbit). Here's the basic idea for any of them:

1) Don't mess with the intakes, you have enough to worry about and a few points of drag coefficient at lower altitudes isn't worth the headache.

2) Basic safety level for air is (Number of Jets) x (Approximate throttle by points)/10 so if the air level is showing .03 and you have two engines, you can run them at 15% throttle. One turbojet is good enough for anything at altitude.

3) At around 30,000m you can kick on the LV-Ns and keep your throttle low and run everything. Keep tapping the throttle lower as you climb. Mechjeb 2 is ok at doing this if you set it to "prevent flameout with safety 20%". A flameout at 5% throttle isn't going to kill you with the LV-Ns going also.

4) The real trick - when the jets cut out, make sure you're still gaining altitude. Its very hard to change your velocity upwards again if you're altitude is dropping. This is the key.

5) When the jets cut out, turn them off, crank the LVN's to full, and pitch up hard. You should have about 60-75 degree AoA and your prograde (yellow circle) should be just above the horizon or more. Your altitude should still be gaining.

6) If your altitude hits 40km, you're golden. My way of monitoring is to watch your "Time to Apoapsis" number. If it goes below zero, you're screwed, if it gets close to zero and creeps back up, you're good. Any number above zero is good until it goes to a BIG number below zero. With LVNs your climb can sometimes be another 5-10 knuckle biting minutes. You have a lot of dV though so don't sweat too much.

7) Your Apoapsis will start to rapidly out-pace your altitude, when it hits the desired orbit then cut the engines or drop them back down and just run them in tiny bursts until you're out of the 69,000 altitude range.

8) With LVNs, you don't burn much fuel, so if your numbers above don't look good, cut engines until you get back down to 20-25km and then try again. Each try you'll be a hair lighter so its that much easier. You should get at least 3 good tries on most of these craft.

All of this becomes very second nature after a while. Using Mechjeb 1 or 2 can also be a good time saver - turn on "Ascent" about step 5 - though you do need to heavily babysit and adjust numbers for each craft.

Edited April 22, 2013 by PolecatEZ

[Tallinu]

For best results, plug in the numbers above into your favorite ascent computer

I'm afraid "the numbers above" in that image are unreadable.

A bunch of these ships look really nice though! For some reason I'd never thought of using LV-Ns on a spaceplane...

[Immashift]

They do indeed look really nice . Performance of the Angry Bird is pretty spectacular - treated it as any other space plane and got it to orbit extremely easily with a pile of fuel remaining.

I gave the Eagle a shot but ran out of oomph at about 25km. Still had plenty of fuel but wasn't going anywhere. I probably did something wrong Gonna have to try again later.

Some very well designed craft though. I too thought LV-N's would have too little TWR for the more active ascent of a space plane.

Also, if you're having trouble seeing numbers on images, try a better resolution or right click on them and "view image". I'm running at 1680x1050 and can see them perfectly in-thread.

Edited April 21, 2013 by Immashift

[Rune]

Some screenshots would do wonders to go with those great introductions. I upload the to imgur, but you may have your own preferences.

Edit: Ok, never mind that. Apparently I was suffering from a horrible case of network adapter settings, making web pages go at the speed of a paralytic snail, and the images didn't load at all. I'll leave it because I hate empty posts without explanation as to what happened.

Rune. And keep at it!

Edited April 21, 2013 by Rune

[Mr Chips]

some very nice SSTO's

[PolecatEZ]

They do indeed look really nice . Performance of the Angry Bird is pretty spectacular - treated it as any other space plane and got it to orbit extremely easily with a pile of fuel remaining.

I gave the Eagle a shot but ran out of oomph at about 25km. Still had plenty of fuel but wasn't going anywhere. I probably did something wrong Gonna have to try again later.

Some very well designed craft though. I too thought LV-N's would have too little TWR for the more active ascent of a space plane.

Also, if you're having trouble seeing numbers on images, try a better resolution or right click on them and "view image". I'm running at 1680x1050 and can see them perfectly in-thread.

I'm going to re-do some of the images anyways so the numbers can be seen a little easier.

I also made detailed instruction above about SSTOs in general.

Puttering out at 25km though sounds like an issue with climb angle. At about 22km or so you want to level out as much as possible (do it slowly, use the SAS). Keep your yellow circle just above the horizon so you'll be gaining altitude slowly and a LOT of speed. At 25km you should still be running at nearly full throttle on just the jets.

Another key to remember - the faster you go = more air in the intakes, more level you are (your nose vs. your prograde vector) = more air in the intakes. More air in the intakes, more power as you climb higher.

I'm going to experiment with bottom mounting some 30 degree angled intakes to see of that helps anything

Edited April 21, 2013 by PolecatEZ

[Immashift]

I'm going to re-do some of the images anyways so the numbers can be seen a little easier.

Another key to remember - the faster you go = more air in the intakes, more level you are (your nose vs. your prograde vector) = more air in the intakes. More air in the intakes, more power as you climb higher.

I'm going to experiment with bottom mounting some 30 degree angled intakes to see of that helps anything

One note* Where I said Eagle in the last post I actually meant the Falcon. Posting at 4am clearly wasn't a great idea.

Oh I can fly them well enough I remember doing that in particular to the aeris 4a at one point, giving it six ram intakes and about twice the radials it had...slightly air-hoggy I know, but it ended up wanting to spin sideways at about 27km doing something like 1500m/s. That design actually runs out of air for the control surfaces before the engines choke. I need to upload that somewhere at some point.

Anyway with the Falcon, the climb angle was non-existent. I treated it like every other space plane. I leveled it out after a 45 degree climb at about 18km, then tried to make it go as flat out as possible. I got it to like 7-800m/s before the speed started *dropping*. I thought pushing it into thinner atmo would help that out so I pushed it into a bit of a climb to about 24km. It went maybe 800m/s before the angle started dropping past the horizon and it started going down. Even lighting up the LV-Ns didn't want to save it.

Gonna try it again right now I think though. See if I can make it behave a little better.

Maybe I'm just doing the ascent slightly off. I remember the KR-X Sparrow BARELY making 80x80km orbit with ZERO fuel remaining and finishing the circularizing with the ion engines pretty regularly.

Edited April 21, 2013 by Immashift

[Climberfx]

Man, the Eagle is wonderful! Those canards on the extreme of wing are great!

Good ships design!

[Immashift]

Okay so I had another crack at the Falcon. Still didn't get it to orbit and I'm not sure what else I can do to convince it. It's ALMOST there, but not quite. I'll go through what I did:

So taking off is simple, and getting it to around 22km is easy, if not a bit long... First thing I notice though is that the wings don't really react well to physics warp, and Ed Kerman here doesn't seem to like it either

So I get it to 22km, and look at the elapsed time - 16 min - this is climbing at 45 degrees the entire time. Yeah, it's a little slow to get up there.

So here's where flameout happens and I'm forced to light the LV-N's. It seems there isn't much space between leveling out and lighting the LV's, I might play with intakes a bit to make it a little more forgiving there.

Here's my final vector where I cut the engines completely and coast to circularizing point:

After trying to circularize, I was left with this trajectory:

So you can see how close I get it. If I could squeeze 200m/s out of it I'd be in orbit. The ascent seems to take abnormally long, and after lighting the LV's, the altitude actually DROPS till you break around 1300 m/s and then it starts climbing again, so you're losing a lot of delta-v trying to fight against the craft's TWR. I'll play with the design a bit and see if I can get it to save a bit more fuel, cause it's almost there.

[Rune]

Just by your description, and without trying out the craft, I think I know what's the problem. On rocket takeover, and with any SSTO really, you want to have a decent ascent speed to get over 35 kms and serious drag losses as soon as you can. So after speeding up at 20-25kms, pitch up until you see about 50m/s on the vertical speed indicator, perhaps lighting the nukes to get an even higher T/W on the pull up maneuver. You can loose an infinite amount of delta-v by staying in atmo.

Rune. The second the jets go out, the atmosphere becomes your biggest enemy.

[Immashift]

So after speeding up at 20-25kms, pitch up until you see about 50m/s on the vertical speed indicator.

That's actually what I've been doing. I get it to 20-25 and I'm holding the plane at a slight climb. When flameout happens I'm lighting the LV-N's, but the thrust is so low that holding the plane at a 45 degree angle makes the pro-grade vector BARELY above the horizon, meaning it's burning piles of fuel going up extremely slowly. Look at the image where I light the LV-N's. That image is taken literally half a second after flameout. You can see the angle vs vector there.

[PolecatEZ]

Ok, had to test it to make sure I didn't mess up. Yes, for that model it is a very long and slow climb. You're pushing almost 20 tons with a single jet engine, which is technically a no-no in the SSTO design book but I wanted to try it anyways. So, I get this pig to about 26000 meters and about 900 m/s, pitch straight up, and light the LVN's. It made it to orbit with about 600 d-V to spare. If I had coasted between 26000-30000m and squeezed a bit more speed before ascent, I probably could have made it with about 1000 d-V (which is about what I did the first test run). You just happened to pick the most challenging of the lot to try out

Good catch on the physics warp, 4 struts and she's rock solid now.

As the other guy said, once you switch off the jets, pitch straight up hard for a near vertical ascent...use RCS if you need a little assist to get your nose up. You want to get out of the atmosphere as fast as possible.

Edited April 22, 2013 by PolecatEZ

[Rune]

Hum. I really have to re-post my crafts. My K-22 has the same powerplant (single jet+2 nukes), and I find the thrust issue to get over 10,000m, not on rocket takeover. I actually use the nukes with the jet to get over 15kms quickly (by 7,000 meters you already get upwards of 700s isp on the nukes). But I also light them when I'm close to flameout, and throttle down to 2/3rds to keep the jets going a bit further and build vertical speed quickly. But, my takeover speed is also much, much higher, about 1,500m/s, so I get much more in-space delta-v out of it. What's stopping you from really speeding up? Drag? Too few intakes? Burning all your jet fuel before then because you climb too slowly?

Edit: Upon close inspection of the screenshots, I see you don't touch the throttle. Bad idea, you can squeeze quite a bit more out of the jets if you throttle them down a bit after flameout.

Rune. Kinda confused.

Edited April 22, 2013 by Rune

[Immashift]

As it's a single engine I probably should have coaxed it into more altitude after flameout, but I'm used to flying my heavily modified aeris which uses two engines and gets up to orbit with almost half its fuel left, so coaxing the engines after flameout is neither necessary nor does any good really.

On a two engine design hovering around flameout is asking for a flatspin, and that idea I guess has sorta stuck cause I only really ever build twin engine planes with one button that switches engines and closes/opens intakes - press one button as close to flameout as possible and you're good to go.

I'll have to try giving the single turbines a little more credit and not mash my "I want to go to space" button the moment the intakeair drops to the minimum that can sustain one engine at full throttle.

It's fun figuring out how I'm doing it wrong gonna give your method a try later today.

[zombiphylax]

Hah! I didn't even notice the Angry Bird was a modified Sparrow until about half-way through this thread. Great work, I'll pilot some of these when I have time to sit down and play for an extended period of time. No need to make a payload delivery bird now.

Immashift, you should be able to get the Sparrow to a very low orbit and back down with LFEs, even at high inclination, but it's really not forgiving. I still have trouble with minimal SSTO designs myself, and there are very few decent videos showing a good launch profile.