Feb 192018
 

The NERVA nuclear rocket, studied throughout the sixties into the early 1970’s, would have been a great way to propel spacecraft. But a nuclear rocket is not the same sort of reactor as is generally designed for use in space to generate electrical power. A NERVA can produce *gigawatts* of thermal energy, energy which is carried away with the high mass flow rate of the hydrogen propellant. Power reactors, on the other hand, are generally designed for several orders of magnitude lower thermal power… a few thermal megawatts, perhaps, to produce a few hundred kilowatts of electricity.

However, the fact remains that a nuclear rocket *is* a nuclear reactor. For most missions it would burn for a few minutes, at most perhaps  few hours, out of a mission lasting perhaps years. It is thus a bit of a shame to waste all that potential. So over the decades many studies have been made for using a nuclear rocket as a power generator .

One such study was reported by Aerojet in 1970. The abstract is HERE, the direct PDF download if HERE.

In this study, the NERVA would pump out 1,500 thermal megawatts during the propulsion phase(producing 75,000 pounds of thrust), dropping to 250 to 505 thermal kilowatts during the power generation phase, enough to create 25 kilowatts of electricity. This would be a very low-power, low-temperature use of the reactor, reducing system efficiency… but still, making use of a reactor that was already there, and not noticeably using up the fission fuel in the reactor. The reactor would be run at very lower power levels and hydrogen would flow through a closed loop built into the reactor; the warmed gaseous hydrogen would flow through a turbogenerator to create electricity; the warm hydrogen would then pass through a radiator built on the outer surface of the hydrogen tank itself.

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 Posted by at 3:27 am
Feb 182018
 

A few decades before the “X-Wing” configuration gained a measure of popularity, Hughes Tool Company made a detailed study of a somewhat similar concept, the “rotor/wing.” This was a three-bladed helicopter rotor attached to a large central lifting surface, either a circular disk or a triangular structure. The rotor was not turned the conventional way with a turbine engine turning a drive shaft, but instead the engine exhaust was ducted through the center and then out to nozzles at the tips of the rotors. Jet thrust would spin the rotors without transmitting torque to the rest of the vehicles; as a consequence only a small tail rotor would be needed, just powerful enough to orient the craft at low airspeeds.

A few configurations were produced, most of which looking much the same. Probably the most well known configuration was shown in US VTOL Projects 01. Shown below is a lesser-known configuration designed for anti-submarine use. Normally the configurations included the turbojet engines within the upper fuselage, close to the hub of the rotor, but this one rather bizarrely put the engines on the tail. No obvious means of ducting the exhaust to the rotor is evident, so presumably a third (or even fourth) engine was tucked into the fuselage somewhere.

 

 Posted by at 2:21 am
Feb 132018
 

Now available: two new US Aerospace Projects issues. Cover art was provided by Rob Parthoens, www.baroba.be

US VTOL Projects #2

US VTOL Projects #2 is now available (see HERE for the entire series). Issue #2 includes:

  • SOS Interceptor: A US Navy Mach 3 aircraft with jettisonable wings
  • Lockheed GL-224-3: A small battlefield surveillance and ground attack plane
  • Phalanx Dragon MP-18: An unconventional  small civilian transport
  • Lockheed L-161-1: An early concept for a variable geometry roadable helicopter
  • GE Supersonic V/STOL: A supersonic strike fighter with flip-out lift fans
  • Convair ANP-VTOL: A nuclear-powered ground-effect craft of the Navy of unusual configuration
  • Piasecki 16H-3: A compound helicopter for high speed passenger transport
  • Boeing Vertol Model 147: A tilt-wing close support fire support design for the US Army

USVP #2 can be downloaded as a PDF file for only $4:

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US Research & Recon Projects #2

US Research & Recon Projects #2 is now available (see HERE for the entire series). Issue #2 includes:

  • Lockheed A-1: The first true design leading to the SR-71
  • Bell MX-2147 Model 105: The high altitude “X-16”
  • Boeing/CRC/AMROC X-34 Reference Configuration: A reusable launcher test vehicle
  • Martin Model 159: A scout/observation float plane
  • NASA-Langley Low-Boom Demonstrator: a recent design to demonstrate quiet SST tech
  • McDonnell-Douglas DC-9 Super 80 Propfan Configuration 1: A fuel efficient transport demo
  • Convair “HAZEL” MC-10: An inflatable Mach 3 plane for the Navy
  • Republic Manned Hypersonic Reconnaissance Vehicle: an early scramjet concept

 

USRP #2 can be downloaded as a PDF file for only $4:

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 Posted by at 12:53 pm
Jan 312018
 

Recently sold on ebay was an apparently old display model. It came without markings, stand or engine nacelles, which were obviously formerly pinned to the rear fuselage in the usual bizjet position. So just what it is is unknown, but it looks too good to be Just Some Guys kitbash. But what it *is* is a headscratcher. It’s clearly a B-1 bomber forward fuselage grafted to a bizjet fuselage, but for what purpose I can’t guess. It doesn’t make sense to use a supersonic bombers cockpit as the cockpit of a small corporate jet, even as a way to utilize existing manufacturing infrastructure. Might it have been meant as a training plane, to teach future B-1 pilots the fine art of flying a Bone? A flying laboratory for the B-1 cockpit to make sure it was set up right?

Or did someone down at the model shop just get a little likkered up?

It appears t be a B-1A cockpit, dating it to the mid/late 70’s.

 Posted by at 11:21 pm
Jan 302018
 

A fanciful late 1950’s Martin Company illustration of a space station. This rendering features a large parabolic solar reflector to concentrate sunlight onto a boiler to run a turbogenerator for electricity, a hockey-puck shaped habitation section (you might think it was meant to rotate, but there are windows in the floor *and* a group of astronauts seemingly standing on the side of the thing, somehow not getting flung off), some standard 1950’s gee-whiz rocketships and something at far right that I can only describe as “a thing.” Maybe it’s meant to represent the radiator for the solar generators working fluid, but if so, it seems a terrible design. Maybe it’s the death ray.

 Posted by at 11:04 pm
Jan 232018
 

Currently winging their way from Ukraine to yours truly are two vintage brochures on the Antonov 225. These were picked up on ebay, purchases made possible by patrons of the APR Patreon. These brochures will in due course end up on the APR Patreon catalog, to be voted for as possible monthly rewards for the patrons.

If you’re interested in helping to preserve this sort of aerospace artifact, and also interested in getting high-rez scans of them, consider signing on to the APR Patreon.

 

 Posted by at 7:35 pm
Jan 172018
 

The Soviet Tsar Bomb, dropped in 1961 and with a yield of around 50 megatons (backed down from the design yield of 100 megatons) is acknowledged as the biggest bomb ever tested. But is it the most powerful bomb ever designed, or ever built? I’ve discovered some snippets of evidence that the US *may* have designed, and even built, an even bigger bomb.

Several frustratingly unenlightening reports give bits and pieces of information on a bomb code-named “Flashback.” This device was apparently air-dropped near Johnston Atoll. “Flashback” was designed by Sandia Labs and flown from Kirtland Air Force Base to Oahu, Hawaii and then to Johnston Atoll. There are some Terrible Quality Photos:

The Flashback bomb was so big that it could not quite fit within the confines of the B-52 bomb bay, and required the removal of the bomb bay doors.

Of course, this could have been purely an aerodynamic shape. Or perhaps it was a large conventional bomb, a giant “Daisy Cutter.” Or perhaps it wasn’t an actual bomb as such, but just some sort of science experiment to be dropped from an aircraft. Lots of possibilities. But those possibilities drop away with some of the hints that are provided, such as:

 

This came from an electromagnetic radiation effects report, describing – seemingly – the effect of radio emissions from the B-52 upon the electronics of the Flashback bomb. Since the bomb projected well below the belly, it was subject not only to very cold temperatures but also to intense radio transmissions from the antennae below the B-52 fuselage, so it makes sense they’d test for that. You don’t want the B-52’s communications to cause the bombs fuzing to go screwy. In this particular test, the parachute was not packed within the tail of the Flashback; instead test instruments were fitted there. More tellingly, “All HE (high explosive) and nuclear components were deleted.” Emphasis mine. Additionally, “A simulator was used to replace the warhead.”

You don’t have a warhead in a science package. You don’t have nuclear components in a conventional bomb. and if this was simply an aerodynamic and mass simulator of a proposed bomb… you wouldn’t remove the nuclear materials, because you wouldn’t have installed them in the first place. You don’t fill a mockup full of jet fuel, after all.

Such details as the weight of the unit and the yield of the device are seemingly not given. But they can be guessed at. A report on testing of the tailfin has this:

I’m not quite sure how that load of 36,000 pounds would relate to any actual forces applied to an actual bomb, but it *may* indicate the weight.

Other reports list the sizes and weights of items to be shipped to Oahu (and then to Johnston Atoll) for the test. Some of them are intriguing… what is “EMPTV?” TV certainly means “test vehicle.” But does “EMP” mean Electromagnetic Pulse? If so, does that mean another bomb-like unit, or just a science package, meant to be *hit* with an EMP to see how it reacts? Or is it a specific EMP generator, to be dropped out of an aircraft? Whatever it is, it weighed 14,500 pounds and was around 221 inches long and perhaps 59 or so inches in diameter, and was quite classified (SRD = Secret Restricted Data… “Data concerning the design, manufacture, or utilization of atomic weapons; production of special nuclear material; or use of special nuclear material in the production of energy“).

And there’s 38,000 pounds of “test equipment,” which could be anything:

There was also this:

Here, the “BTV” is the “Big Test Vehicle,” 25,000 pounds, 309 inches long by up to 76 inches in diameter, also classified SRD. Big as this is, though, it’s possibly not the device hanging below the B-52’s belly; the BTV is referenced several times in a way that seems to make it distinct from the Flashback Test Vehicle. But perhaps they are the same thing.

The Flashback Test Vehicle, fortunately, was shown in a fair diagram of a wind tunnel model. Full scale, it was 297 inches long (not counting parachute pack or what appear to be antennae) and was ~96 inches in diameter. This makes it bigger, and presumably heavier, than the BTV. So 36,000 pounds is not unreasonable.

Other ill-described tests show the Flashback as a much smaller unit than the bomb. This, *perhaps,* is merely the “physics package” of the device. This test, illustrated with one of histories worst-quality photos, was carried out in a very cold high altitude chamber, and shows two more mysteries: the “Companion Test Vehicles,” or CTVs, which are unexplained. Speculating wildly, they might have been designed to have the same ballistic properties as the Flashback, so if you drop them from the B-52 along with the Flashback, they’ll fall along with it, following the same trajectory and staying reasonably close. Perhaps thy had cameras. perhaps they had sensors. Perhaps they had transmitters. Who knows.

And there was also the “UTV.” No further data.

Perhaps the Flashback, BTV, EMPTV and UTV were all different sizes of new gigantic bombs…?

Code names generally have no relationship to the subject, but are chosen essentially at random. One would never know that “Copper Canyon” was a program to develop a scramjet SSTO. Similarly, “Operation Paddlewheel” tells nothing. But perhaps, just barely, “Flashback” might have some meaning. Comparing the Flashback to the Tsar Bomb, it it remarkable how similar they are in terms of both size and shape. One might be forgiven for wondering if Flashback was the end result of someone trying to design a Really Big Bomb based on nothing more than a verbal description of the Tsar Bomb, given, perhaps, by a spy or defector. So *perhaps* this project was a “flash back” to the earlier Soviet design. If so, what was the purpose? Was it to give the United States the same insanely pointless capability? Or was it just to find out what the capabilities and limitations the Soviets had gifted or saddled themselves with?

Using the wind tunnel model diagram, I’ve reconstructed the Flashback to scale with the Tsar Bomb:

As can be seen, the Flashback had much the same configuration, but was substantially “fatter.” Impossible to say if that was because the US designers needed the extra diameter to get the same yield (theoretically 100 megatons), or if Sandia Labs went head and designed themselves an even bigger bang. What use is a 200 megaton bomb? Not much. But then, neither is a 100 megaton bomb, especially one so big that the carrier aircraft essentially has to *lumber* to the target all the while carrying the worlds largest bullseye.

As always, if anyone has any further info, I’d love to see it.

PS: I’ve taken the Flashback model and have turned it into 2D CAD diagrams, including scale comparison with the Tsar and showing it stuffed into the B-52’s belly. This diagram will be one of this months rewards for Patrons of the APR Patreon. A simplified version will be included at the $5 level; the full diagram will be in the $8 level rewards package. So if you’d like access… sign up for the APR Patreon.

UPDATE:

It’s good to get a fresh perspective. Sadly, the perspective emailed to me was that the Flashback sure looked like a missile nosecone. So I pulled up the Flashback diagram I made from the wind tunnel model diagrams and put the RV from the Titan II ICBM on top of it. It’s not an exact match, but it’s distressingly close. If it wasn’t for the noticeably larger radius of the Flashbacks nose, I’d say it was spot-on… the outer diameter and angle are incredibly close matches.

So…what would be the point of that? Some sort of science experiment, clearly, rather than a weapons test. But what point would there be in dropping a Titan RV from a B-52? Why dangle it from a chute? Why add the heavy tail & fin assembly?

If it turns out that this was an experiment with the Titan RV, that would be less interesting than the revelation that the US developed a 50 to 100 megaton nuke. But it’s still interesting. Just not *as* interesting.

 Posted by at 9:31 pm
Jan 142018
 

A 1966 Aerojet concept for a space probe with a nuclear reactor and ion engines. Note the largish thermal radiator “wings;” such things are usually left off spacecraft in science fiction, but they are a vital part of any nuclear spacecraft. Nukes, after all, are simply heat sources; in order to get useful electrical power out of them, the heat must be used to boil a working fluid which runs a turbogenerator; and the hot gas then needs to be condensed back to a liquid by radiating the heat way to space. And thermal radiation is a terribly slow and weak process, necessitating large radiators. Electricity can also be created with thermionic systems, which generate electricity across a thermal differential… hot on one side, cold on the other. But unless the cold side it attached to some radiators, the cold side will soon be just as hot as the hot side, and then… no thermal differential, no power generation.

Note also that even with a substantial powerplant and the sizable bank of ion engines, acceleration is going to be creakingly slow. Thus you can get away with spindly structures. The reactor itself is the tiny little tin can-looking thing, top and centerline; the U-shaped structure around it is a radiation shield protecting the electronics, structure and radiators from the radiation spat out by the reactor.

 Posted by at 2:38 am
Jan 092018
 

The Curtiss-Wright X-19 was a reasonably successful experimental tilt-prop VTOL aircraft from the first half of the 1960’s. Two aircraft were built; one crashed, one is at the USAF Museum in Dayton (I believe it’s in a restoration facility). The Defense Technical Information Center has two CW documents in PDF format that cover the technology of the X-19 in some detail:

THE X-19 V/STOL TECHNOLOGY: A CRITICAL REVIEW – final report

abstract

THE X-19 V/STOL TECHNOLOGY: A CRITICAL REVIEW – technical report

abstract

One of the documents includes a fold-out three-view diagram of the X-19, scanned in glorious Extra No color two-bit black and white as two separate pages. I’ve stitched them back together and tried to make the diagram look reasonably good; I’ve uploaded the full-rez result of my effort to the 2018-0 APR Extras folder on Dropbox, available to all APR patrons at the $4 level and higher.

Support the APR Patreon to help bring more of this sort of thing to light!

 

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 Posted by at 12:04 am