Reaching for the Stars [PH] - Jane's VI 3 Feb 15

[Wallenberg]

I'm sorry this is rather off-topic - but with KSP 0.23 and your recent mod updates I seem to have lost track of your "German" (like on the 'Armbrust' missile) and differently styled procedural fairings . In what mod are they included?

[NathanKell]

Realism Overhaul.

[Captain_Party]

I just want the Brits to land on the Moon first... *crosses fingers*

[NathanKell]

Ok. I have all the pics for my sounding rocket post but as it turns out I already wrote a novel and just described the American rocket. So I've split it up into two posts and I'll write the German one soon.

So, at long last: Part 1 (!) is arriving.

Also, A cookie for each reference someone gets in the post. Note that the name Wren was chosen with special care, among other things.

[NathanKell]

I: Higher, Faster Part 1

US Sounding Rockets and their Wartime Roots

During the Second World War, rocketry finally got the funding many in the American Rocketry Society had begged for from the government--but not in a way they had anticipated. GALCIT was a key player in Project Prometheus and nearly all research and engineering revolved around that massive project to build an intercontinental ballistic missile. For this, reliable upper-atmosphere readings were necessary, and so sounding rockets received some of the windfall of funding. Late in the war, when it was obvious that Prometheus would not be ready in time, and that a heavy bomber would be sufficient to carry nuclear bombs, sounding rockets retained considerable priority, along with continuing Navy balloon flights, since a fast, high-flying bomber would itself need high atmospheric data.

While GALCIT focused primarily on Prometheus, that program, done mostly in cooperation with the Air Force, was joined with another project of the newly established Jet Propulsion Laboratory at GACLIT (JPL) --JATO. Jet Assisted Takeoff--although later jets would come to mean air-breathing jets rather than rockets, the name for both JATO and JPL stuck--was a program run in concert with the Navy to provide small disposable boosters which could be used to drastically shorten takeoff runs for carrier aircraft and increase their maximum takeoff weight, as little time for acceleration on a short deck was a limiting factor for payload (land-based aircraft could manage larger payloads with long runways to accelerate down.) The JATO project at first used Goddard's preferred liquid propulsion, but it soon proved inadequate for service needs; instead JPL turned to solid fuel rockets, which were safer and could be built and then stored for months at a time. Frank Buturović and other students, postdocs, and fellows at JPL had been testing various solid fuel combinations for use in Navy and Air Force rocket-propelled weapons, and a cluster of these rockets--in a longer, thinner form such that the burntime would be longer and peak thrust lower--would enter service as detachable boosters for Navy aircraft (and Air Force aircraft flying from unprepared strips) in the final year of the war.

In the closing months of the war, with the Mighty Mouse and Fat Albert rockets and the JATO packs no longer in such high demand, Buturović mated an old Fat Albert Mk. 1 thrust section with the sounding rocket he had designed years before for his doctoral thesis, the Wren. Hitherto the Wren had reached an apogee of only about 25km--perfectly high enough for use "testing the waters" for aircraft, but still only a bit into the stratosphere. Mated to an obsolete Fat Albert Mk. 1 booster, Buturović hoped to be able to reach high into the stratosphere and perhaps determine if it merely continued up and up in a single atmospheric "bloc" until it faded away altogether, or whether there was a third layer of atmosphere, distinct from the troposphere and stratosphere, extending above the stratosphere.

The Wren was a simple design, and already showing its age. Thin steel-braced aluminum skin enclosed two pressurized propellant tanks: a large tank of red fuming nitric acid (the oxidizer) in the fat cylinder at the base, and inside the conical section above that a smaller tank of aniline, the fuel. The propellants were toxic, but they at least had the merit of being hypergolic, which greatly simplified the engine. The engine, a later model of which was designated LR22, was a very simple affair: pressure-fed and needing no ignition system due to its hypergolic propellants, with a very simple bell nozzle that JPL had developed from the first, conical, efforts. The engine produced 11.53kN of thrust at sea level, rising to over 15kN as air pressure decreased. Specific impulse was 182 seconds at sea level, rising past 235s in the best vacuum JPL could create to test the engine (later testing would yield figures of 15.2kN and 240s in near-perfect vacuum). The other main components of the rocket were the nose cone, sided with heavier, thicker steel and insulation to protect the sensors from heat, and the sensor bay immediately below the nosecone. Inside were a barometer and a thermometer, and a small radio to transmit results back to the ground. This was necessary since the rocket was unrecoverable and was expected either to break apart under heat and stress on return, or crash and be destroyed. Finally, three fins were added near the rear; these would provide stability in flight and keep the rocket pointed into the airstream; beyond this, the rocket was without attitude control.

Mission Control:

Jet Propulsion Laboratory

Vehicle:

Boosted Wren

Launch Site:

Prometheus Project testing site, Sinclair AFB, California.

Launch Date:

September 12, 1944

Objective:

Return readings from the upper atmosphere

Intended Orbit:

Suborbital

Description:

Launch the Wren sounding rocket on a Fat Albert Mk. 1 booster, attempt to exit the stratosphere (if there is something beyond the stratosphere), return temperature and pressure readings.

Outcome:

Success.

Wren

T-02:00:00 Engineering statistics; Boosted Wren being assembled in a hanger at Sinclair.

T+0:00:00 Liftoff from Pad 3 at Sinclair. (Note scorchmarks from LR18 static fires). Since Wren is without attitude control, it lifts off at a slight angle to ensure it will not land on the pad.

T+0:00:02 Fat Albert booster burnout and separation.

T+0:00:03 The Wren's LR22 lights.

T+0:00:06 Burning skyward. It's a beautiful day, and the ground crew expect to be able to track the rocket visually for quite a distance.

T+0:00:42 Burnout, fuel exhausted. The Wren is well past the speed of sound.

The California coast can be seen below.

T+0:01:56 Apogee. The Wren has been returning good data, but as of its 43km apogee it looks like the stratosphere is all there is; pressure has been decreasing steadily and there has been no discontinuity since the tropopause.

T+0:02:30 The Wren has stabilized in attitude for the long fall to Earth.

Screaming in towards the headland.

Well past the sound barrier on descent.

T+0:03:40 just prior to impact.

Fat Albert

Fat Albert was in simple terms a large clustered solid rocket booster, and a 340kg 11in (28cm) shell, originally designed for the main armament of the Alaska class of supercruisers but surplus after they were cancelled. Since the diameter of the booster was quite a bit larger, some steel fairing bridged between the shell's 28cm width and the 50cm of the booster. Intended to give naval carrier attack aircraft standoff capability, it was to be carried in lieu of a torpedo or 2000lb bomb by torpedo and dive bombers respectively. The Mighty Mouse, with only a 400lb warhead, was sized for fighters doing suppression or light attack duty. As an air-launched weapon it was accurate out to about a mile. It was also considered for deployment as a ground-launched bunker-buster for the Marine Corps. The following is a range test of the first model of Fat Albert, the Mk1 (later marks would include larger solid rockets, nearly quadrupling the burn time and greatly extending range).

Mounted for testing

In flight; launched at a 45 degree angle for maximum range.

Burnout. The eight clustered solid motors can be easily seen.

Impact: 29 seconds from launch, 3.3km downrange, 900m apogee.

Edited March 13, 2014 by NathanKell
RETCONZ whee!

[Patupi]

Yay, storytime! Like the look of the rockets, and the 'big' ones seen against the launchpad really show the scale of what is to come. They'll redefine what they consider large soon enough!

[NathanKell]

Thanks.

Yeah, this is going to span everything from 0.3m sounding rockets (this one was 0.5m, though) all the way up to 10m+ SHLLVs (assuming I make it that far). If you want to feast your eyes on some of those super-heavies, though, check out the RSS subreddit where Ferram and others have been posting some glorious monstrosities.

Also: cookies remain unclaimed.

[ferram4]

Well, I gather that the Wren is the WAC Corporal and the Fat Albert is the Tiny Tim, but I'm not finding the actual significance of "Wren" as a name, besides it being a type of small bird.

What happens if you cluster Fat Albert boosters? Can you produce a 3 stage rocket that will get it high enough?

[NathanKell]

Yup!

Wren is a pun. WAC->WRNS

Assuredly, though stability may be an issue. Though Frank may go straight for putting it atop a Granite, once Germany retakes the lead in the next post...

EDIT: Also, this is a darn sight higher-performing than the WAC Corporal+Tiny Tim; I've just assumed that a similar tech-level war's requirements would lead to a similar kind of solid fuel booster (although a much larger one in this case; Tiny Tim had a 500lb bomb and about 1/4 the solid fuel this does IIRC), and a similar doctoral student would have a similar project, just more resources at his disposal ITTL (though his sustainer, with a larger payload, has 100m/s less dV).

Here's a real WAC Corporal (sorry for blue; should be yellow/black, I know. And for some reason it shows 12kN when the cfg says 6.7 as is proper. Doesn't change the stats though.)

Edited January 22, 2014 by NathanKell

[NathanKell]

Actually, I retract my statement; doing a bit more looking it appears I had bad data on Tiny Tim. My Wren-Fat Albert is actually underpowered, which, combined with its higher drag means markedly worse performance than the real WAC Corporal and Tiny Tim.

Heh, you know what it was? This was a pre-RF craft, so the separatrons had 1/4 the fuel they should have. I fixed the tank but forgot about the boosters.

Even without that though, I was able to replicate real performance with a second booster and a slightly lighter sustainer (higher dV, but also higher drag).

Edited January 22, 2014 by NathanKell

[wminsing]

Glad to see this updated, one the neatest AAR's to come out of KSP yet.

-Will

[NathanKell]

II: Higher, Faster Part 2

Postwar Sounding Rockets and Their Wartime Roots (Germany)

While the Verein für Raumschiffahrt had never disbanded during the war, it was at best in a holding pattern even before it began. As the 1930s drew onward and Russia became ever more belligerent (and more industrialized) rearmament intensified; innovative officers in the more firmly middle class Kaiserliche Marine, and in the Luftstreitkräfte (which had been made independent from the Heer late in the Great War), looked to rockets as perhaps a way to even the odds against the titan to the east. Even earlier both the navy and the air force had reached out to the VfR, given their meteorological needs and the potential for sounding rockets to deliver instrument packages to the higher atmosphere; as the ties built, and like-minded officers were assigned as liaisons, at some point the idea of ballistic missiles took hold. Given Anglo-German advances in RADAR, and Russian shows of strength in the air, by the mid 30s the idea that "the bomber would always get through" was dying. Besides, Russia was so vast (and, at the time, bombers' ranges so feeble) it appeared that to build an airplane that could get to its target and return was an impossible task; a missile, which needed only to arrive, must be simpler.

Many had joined the VfR in the service of a shining, peaceful future, however, and would not see their rockets fly in the service of death. A similar phenomenon occurred in America, later, during the buildup of the Prometheus Project (and the Knoxville Project), as some scientists and engineers would not stand to see either rocketry or atomic physics used in that way. While some members of the VfR would finally offer their services after the invasion of the Fatherland, it would not be until well after the War that there was anything approaching a full reconciliation; a similar pattern occurred with the American Rocketry Society.

One of the first projects that the new Raketenamt of the Reichwaffenamt ordered was an upscale and conversion of the latest mark of Repulsor sounding rocket which the VfR had been testing. The Repulsor series had been funded in part by the Kaiser, a very generous patron of the VfR; with his support the VfR had moved to Berlin, under the joint aegis of Karman and Oberth at the Kaiser Friedrich Institute. There, with funding aplenty, they could build much larger rockets than their previous Mirak "Minimum Rocket" designs. Repulsors used gyroscope-based inertial guidance and alcohol-liquid oxygen engines; these soon graduated from the old pressure-fed designs to new turbompump-fed ones (powered by steam from catalyzed high-test peroxide). To solve the heating problem in the nozzle, Repulsors used the regenerative cooling method developed by Irene Bredt and Eugen Sänger, a newcomer to the VfR and later Bredt's husband.

As secrecy became an issue rocket testing was moved from the VfR's Raketenflugplatze in Berlin to a hunting estate of the Kaiser some ways out of the city, northeast of Potsdam. It was there the first government-sponsored Repulsor was tested. At the time of its first test-firing in 1938 it was the largest and most powerful liquid-fueled rocket in the world, with an engine capable of just over 20kN of thrust and weighing over half a ton wet, with instruments, parachutes, and ballast. By the start of the war it had gained a 250kg warhead, a 50km range, and a new name: Pfeil (arrow); by the end, it had a 29kN engine, a 340kg warhead, a 75km range, and a series of more famous descendents.

After the war, surplus Pfeils regained their old name of Repulsor and performed valuable high-altitude research. The post-war Repulsor, like its pre-war predecessors, was equipped with parachutes and scientific equipment. However, as it was by then designed for a 340kg weight right in the nose, its light scientific payload required ballasting, limited its altitude. Nonetheless, it was sufficiently powerful to bring its instruments up to nearly 60 kilometers above the earth and return them safely to the ground. In so doing, it gave German scientists the first opportunity to make observations of a new layer of atmosphere above the stratosphere: the mesosphere, which begins approximately 50km above the surface.

The Repulsor/Pfeil was a simple rocket. At the front was either an aluminum nosecone fairing or a steel-encased warhead, respectively. For civilian use, inside the nose cone would be ballast and scientific instruments, and four small parachutes. Behind the nose section was the inertial guidance unit and its gyroscopes. Behind that were the liquid oxygen tank and the 75% ethanol/25% water fuel tank. Behind that came the engine section. First was a small tank of high test hydrogen peroxide and a catalyst to break it down into steam; this would drive the turbopump. The turbopump, below that, would feed the oxidizer and fuel to the mixing chamber at high pressure. The model "A" engine--A4 in the late-war Pfeils--had a single large mixing and thrust chamber, which fed a large conical nozzle, regeneratively cooled. Carbon vanes in the exhaust would, on command from the guidance unit, divert it; the engine itself did not gimbal. The Armbrust used a derivative, the model B engine; it used 8 scaled-up A2 thrust chambers, and a similar thrust-vectoring system. The final distinctive feature of the Repulsor/Pfeil was its fins. Purely for stability, unlike later rockets they resembled the rakish designs gracing the covers of science fiction and science "fact" magazines of the 1920s and 30s. They had also been designed to cushion the tail-first landing of the early civilian Repulsors, and that ability, though unused, remained during the rocket's later use, only to be called on again when the Pfeils were released from military service and returned to their sounding rocket roots.

Mission:

Flight 12b

Mission Control:

Kaiser Friedrich Institute / VfR

Vehicle:

Repulsor (ex-Pfeil no. 17582)

Launch Site:

Northeast of Potsdam, on the shore of the Grosser Wannsee

Objective:

Return readings from the upper atmosphere

Intended Orbit:

Suborbital

Description:

Launch the Repulsor sounding rocket, attempt to exit the stratosphere (if there is something beyond the stratosphere), return rocket and instrumentation (with data) to the ground.

Outcome:

Success

Repulsor

T-07:00:00 Engineering statistics; Repulsor being checked out in Potsdam prior to journey to launch site.

T+0:00:00 Repulsor positioned on its launch trailer just inshore from the Grosser Wannsee lake.

T+0:00:01 Liftoff from trailer.

T+0:00:15 Nearing supersonic velocity. Pitch program has begun, so the rocket will not land on top of its trailer!

T+0:00:35 Burning skyward. Shoreline can now be seen. Nearing burnout.

T+0:00:42 Burnout, fuel exhausted. The atmosphere has so little density this high (20km) that all visible atmospheric effects have ceased. Velocity at burnout just over a kilometer per second.

The Repulsor has begun to turn significantly under the influence of air pressure, to stay aligned with its velocity vector (a gravity turn--gravity "pulls" the velocity vector downwards and the rocket follows).

T+0:02:22 Apogee (59km), and success! The Repulsor has passed through a boundary layer and into a new kind of atmosphere, the mesosphere.

T+0:02:30 Nose fairing separation, revealing the instruments and parachutes.

The parachutes are gradually fed out; as yet there is not enough air pressure to fully inflate them (nor even to stabilize the rocket in a tail-first attitude).

T+0:06:55 The parachutes deploy fully at around 600m AGL; the rocket swings to tail-first attitude.

T+0:07:20 Stabilized.

T+0:09:21 Landed!

Pfeil

Here is a late-war mark of the Pfeil tactical ballistic missile. It had the punch of a dreadnought's shell, like the American Fat Albert, but twice the range of a Second World War battleship's main battery. Used en masse against fortified Russian positions it proved moderately effective, and while expensive (though obviously less so than the larger, more sophisticated Armbrust) it did prove far more versatile than the massive railway guns that would otherwise have need been employed.

This launch occurred in mid 1945, months after the Winter Peace that ended the war. Pfeil 12246 was launched from the Kaiserliche Marine sounding rocket station at Wilhelmshaven.

Mounted for testing

In flight; pitch program beginning for maximum-range flight.

Burnout. The rocket will manage 77km downrange with a 20km apogee, the best yet.

Edited January 26, 2014 by NathanKell

[Captain_Party]

Amazing Nathan. Props and +1. Small error, you said "Anglo-British", which is basically saying "British-British"

Edited January 25, 2014 by Captain_Party

[borisperrons]

Great writing as usual! Congrats!

[FanaticalFighter]

Awesome writing, Nathan!

[NathanKell]

Captain Party: thanks, and thanks for that catch! Should be clear it was to be Anglo-German from the context, and I read the paragraph at least five times before posting and each time would have sworn I *read* "Anglo-German." Will fix on my offline copy and edit appropriately...

borisperrons, FanaticalFighter: thanks so much!

[Patupi]

I just imagine you poring over reports, sheets of statistics and blue-prints before posting one of these NathanKell... Then I realise nowadays that would all be gleaned via the web. Doesn't quite have the same mistique, but still love the amount of effort you put into the realism of these. Have some rep

[NathanKell]

Patupi: thanks so much!

And yeah, you don't want to know how many tabs I have open, between this and RF and RO and...

I'm away on a trip and have only my meh laptop and some spotty wifi, but I'll see what I can do.

That said, a couple teasers.

Supermarine Swift, the "workhorse of the war." The best jet hunter of the war to see widespread deployment and use. Seen here in RAF green, though it would go on to serve with dozens of nations after the war. Note swept wings, "flying" tail, and "stovepipe" design where the center of the fuselage is all intake, jet, and exhaust.

Wright-Northrop Dagger, a high-performance "delta wing" hunter that was on the drawing board when the war ended. Shown here in USAF hiviz. Note area-ruled fuselage.

[MedievalNerd]

The fact that you even manage to do these in between the hurdles of god knows how many mods makes you insane!

You are insane, but we love you for it.

Cheers,

[Patupi]

Viva la insanity! *grins* Keep up the good madness, I mean good work NathanKell

[NathanKell]

Hah, thanks folks.

Due to be able to build, but not really fly (or at least not well enough for good screenshots) I now have, I believe, the craft for the next few posts. I'm still deciding on satellites and the US launcher config, but I believe I can now reveal the JRC Mk III. Here it is on its record-breaking flight, after "buzzing" the German rocket establishment on Pemba Island, Deutsch-OstAfrika. Gerry Sayer at the controls. (Pemba is the farther island; Unguja Island [Zanzibar proper] is the nearer).

Breaking Mach 2 without reheat. Supercruise indeed.

Edited February 11, 2014 by NathanKell

[Redrobin]

Looking forward to more rockets

[Turbojet]

Does that mod come with the Javelin, Swift or Meteor?

[NathanKell]

Redrobin: rockets will return soon (as well posting in general) when I return from my trip.

Turbojet: what mod?

All the craft I make I will post. As this is alternate history, you won't see me making any real aircraft, or rockets /spacecraft, but they might, as Mark Twain says, "rhyme" real things. Form follows function, similar design environments and requirements lead to similar approaches

[NathanKell]

I had really hoped to post the next update Tuesday, as I had finally returned, but literally the day we got back from our trip my GF got the call that her best friend's mother died suddenly, so we scrambled for tickets and scrabbled together clothes and are now gone again, for another week. My apologies for the continuing delay.