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Is there a better way to ID that concept?
History of Stealth
- Thread starter Wahubna
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Is there a better way to ID that concept?
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I have my suspicions, but not definitively at this time.
Some of those from my site: http://acme-engineering.nl/curious/Lampyridae.htm
Lockheed D-21 TAGBOARD (1966)
Ryan AQM-91 COMPASS ARROW (1968)
The two drones I added were not true competitors, yet they were developped a) in parallel b) with the same important characteristic (pre-stealth) and c) same target : Lop Nor, Xinjiang. The PRC nuclear testing grounds.
The main difference was that COMPASS ARROW was subsonic and recoverable. When TAGBOARD was Mach 3, hence not recoverable : except for the camera and film, ejected.
- Lockheed did a faster and better job than Ryan, flying two years earlier, albeit they had to shift the launcher from SR-71 to B-52H.
- But in the end, Nixon trip to China led to both eye-watering expensive drones being canned, then send in storage.
- D-21 flew a handful of missions in 1969-1971, all of them failed. AQM-91 flew zero missions.
According to Ben Rich, circa 1974-75 Clarence Johnson did not thought it was possible to get a lower RCS than the D-21. Yet they succeded with Have Blue.
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Why would this T-33 be on the list? (I am not familiar with it)
Why would ARES be on this list? It's on my personal list just for it being a cool little flying gun.
Swan
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https://airandspace.si.edu/explore/researchers/projects/horten-ho-229-v3-preservation/stealthy#:~:text=In his later life, Reimar,decades ahead of its time.
Please explain how the National Air and Space museum is wrong? Note that everything above and below this line is from the museum and I have given them the credit. So why are you deleting this and claiming that I am responsible for what the museum has said?
Is it Stealthy?
In his later life, Reimar Horten promoted the idea that the Horten Ho 229 V3 was intended to be built as a stealth aircraft, which would have placed this jet’s design several decades ahead of its time. Reimar Horten claimed that he wanted to add charcoal to the adhesive layers of the plywood skin of the production model to render it invisible to radar, because the charcoal “should diffuse radar beams, and make the aircraft invisible on radar” (Horten and Selinger 1983). This statement was published in his 1983 co-authored book Nurflugel (which translates as “only the wing”). While this statement refers to the never-made production model, it seems possible that the experimental charcoal addition could have been used on the Horten Ho 229 V3 prototype. The mere mention of early stealth technology sparked the imagination of aircraft enthusiasts across the world and spurred vibrant debate within the aviation community.The stealth myth has been growing since the 1980s and was invigorated when the National Geographic Channel, in collaboration with Northrup Grumman, produced a documentary called "Hitler's Stealth Fighter" in 2009. The program featured the Horten Ho 229 V3 as a potential "Wonder Weapon" that arrived too late in the war to be used (Myth Merchant Films, 2009). The documentary also referred to the jet's storage location as "a secret government warehouse," which added to the mystique of this artifact. Since the airing of the documentary, public pressure has increased to remove the jet from its so-called secret government warehouse and put it on display. In fact, this secret warehouse is the Museum's Paul E. Garber Facility in Suitland, Maryland where a team of conservators, material scientists, a curator, and aircraft mechanic has been evaluating the aircraft.
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This T-33 was covered in RAM and conducted a flight test program to see how much it affected both detectability and flying qualities.
This aircraft was originally designed as a high-altitude bomber. The specification called for an aircraft capable of flying over the British Chain Home defences broadcasting on the 25 MHz band, the aircraft was not expected to be undetectable but by the time it was detected it would be too late for interceptors to reach it.
In such attacks, delaying detection was very important, and the use of RAM materials would surely have been useful.
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If the RAM materials worked. Charcoal isn't particularly good RAM, and the means to develop and produce useful RAM did not come until the late 1950s.
When Northrop tested a model of the Horten on their RCS range they found the frontal RCS to be 4dBsm less than a Bf-109 at CHAIN HOME frequencies. They did not model the inlets or turbines (and cockpit?), so take that as you will.
From Wikipedia
Chain Home - Wikipedia
When the target was first detected at long range, the signal typically did not have enough of a return in the second lobe to perform height finding. This only became possible as the aircraft approached the station. Eventually this problem would recur as the target centred itself in the second lobe, and so forth. Additionally, it was not possible to determine the difference between a signal being compared between the first and second or second and third lobe, which caused some ambiguity at short ranges. However, as the altitude was likely determined long before this, this tended not to be a problem in practice.
This pattern left a set of distinct angles where reception in both lobes was very low. To address this, a second set of receiver antennas was installed at 45 feet (14 m). When the lower antennas were used, the pattern was shifted upward, providing strong reception in the "gaps", at the cost of diminished long-range reception due to the higher angles.
There also existed an antiradar painting for airplanes, the ‘Schornsteinfeger’ developed in the BHF (Hochfrequenzinstitut) of Travemünde. A radar camouflage material consisting of a thick bituminous paint heavily loaded with carbon. When applied in thickness carefully calculated in relation to the radar frequency the arriving signal would be trapped within the dielectric material and its return energy damped out and transformed itself in heat. The painting was more efficient if applied over non-metallic structures predecessors of the current composite materials.
The most efficient device was the ‘IG-Jaumann’ developed by IG Farben. It consisted of 8 cm thick panels formed by 7 layers of conductive material plastic/carbon separated by layers of di-electric ‘Igelit’ polyvinylchloride. It was used against the wavelengths between 2 and 50 cm effectively reducing the reflectivity of -20dB over 2.15 GHz. However, it could only be manufactured in curved or straight panels, which made its use on aircrafts very difficult.
At least three aircraft manufacturers were experimenting with antiradar materials during the last months of the war. The designer Kurt Tank of the firm Focke Wulf built the night fighter Ta 154 with wood to make it less easily detected by the radars of the Allied. The structure was of plywood Lignofol L90 and the coating was of a new plastic known as ‘Dynal Z5’ manufactured by Dynamit Nobel-Troisdorff.
The elasticity modules should be assembled with synthetic glue named ‘Tego-Film’ (equivalent to the ‘Araldite’ used in the British Mosquito). The ‘Tego-Film’ was made of phenolic resin glues. Unfortunately it could not be used for the mass production of the Ta 154 as the manufacturing plant that synthesised it (Goldmann Company) was destroyed during the bombing of Wuppertal. The replacing of the ‘Tego Film’ by the ‘Kaurit’ adhesive, manufactured by Dynamit AG in Leverkausen, was not possible due to its high acid rate that eventually destroyed the wood.
The Ta 154 was not the only casualty of the lack of ‘Tego-Film’ suffered by the ‘Stealth’ project. The construction of the prototype Lippisch P.11, a ‘Schnellbomber’ flying wing equipped with two HeS 011 turbojets, was also stopped. It was a fast bomber able to fly at high altitude by means of radio navigation devices and incorporated different antiradar technologies. The structure was of plywood and the coating of Dynal Z5.
It was expected that the high flight profile, the ‘Stealth’ flying wing configuration and the ‘Schornsteinfeger’ painting would make it impossible to detect. There was also a plan to build a night fighter version. By the end of the war only the central section of the wing has been built.
For their own part, the Gotha/Horten team created several designs of flying wing fitted with excellent antiradar characteristics due to their outer shape (without any tailfin) and to their moulded wood coating ‘Formholz’ -15 mm plywood/carbon sawdust/plywood composition- and ‘Tronal’ plastic.
red admiral
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Which specification? What RCS values did they want to achieve? Over what aspects? Frequencies? etc.
From what's available then there doesn't seem anything that links Ho 229 with "stealth" before the 80s
Was there any connection between the US trials using a RAM. covered Lockheed T-33, project 'Passport Visa' (followed by a RAM. covered U-2) and the Plessey DX.3 X-band coating material trialled on a Balliol and Canberra airframe ?
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Any source for this? I'd like to know more
Because there isn't anything! At any rate, it does 'foreshadow' which is fine. But I view it as outside the core stealth history. Just a fun look-a-like.
I would prefer to flesh out the timeline beyond that dead horse and the various camo paint schemes or we have to cover literally every paint scheme that has flown which I have no interest in.
I'm hoping by compiling a timeline of all these we could shed light on what connections may be out there. Or at least common origin points. MBB Lampyridae for example maybe came from German engineers reaching the same conclusion as Skunk Works engineers after reading a certain paper.
It seems RAMs were prevalent in WW2.
Based on the extensive back-and-forth struggle between ASW radar looking for U-Boat periscopes and German periscope RAM coatings in addition to the extensive night fighter war and exploits of No 100 Group in WW2 that Britain had a strong LO foundation. They should have had ample understanding of radar frequencies and how they can be manipulated to produce a return or not produce a return. I would argue the RAF were LO front runners in the 40s.
Unless there was an explicit, and verifiable source of information that says a given WW2 aircraft was laid out for LO I would have to say the timeline starts post WW2. WW2 covering the science of RAMs and fundamentals of electromagnetics.
Whisperstream
I really should change my personal text
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Altogether, 21 of the aircraft on my list came from a graphic that listed LO aircraft in chronological order from 1957 (U-2 with RAINBOW treatments) to 2014 (unspecified, classified LO Platform). I was happy to see the PASSPORT VISA modified T-33A as that program doesn't get a lot of love. The Model 151 ARES was as much of a surprise to me as it was to you, but it was on the list. The graphic was created by the classified CTF that worked on the unspecified 2014 platform.
Fair enough, I think then by my criteria I'll leave ARES off for now (this list anyways). I have long wanted to model ARES anyways though so probably will still make it. But that is a different topic!
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Whisperstream
I really should change my personal text
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There are some declassified CIA documents, but a name like PASSPORT VISA makes searching rather difficult. Project pilots included Gus Grissom and Larry McClain. I first learned about this project from Larry, who said it was his first assignment after graduating from the USAF Test Pilot School.
I have no data on an official specification of the RLM, the only reference to this is a meeting between Göring and the aircraft manufacturers (Karinhall Mach 18, 1943) complaining that the industry had failed to comply with the Schnellbomber specification of October 20, 1942 (1,000 kg payload, a penetration depth of 1,046 km -one third of the operational range- and a top speed of 700 km/h, later on increased to 1,000 km/h, at operational altitude). After this conference, different projects of fast jet bombers began to appear with flying wing configuration with a combat ceiling and max speed superior to any piston fighter of the Allies, designed for horizontal bombing at high altitude (46,000 ft).
The flying wing configuration allowed the increase of load at higher altitude. Considering that the turbojets consumed a third at 33,000 ft than at sea level, the schnellbomber could be smaller and transport less fuel and more payload.
These projects included composite materials in their construction. Some believe that this type of structure might have had certain stealth qualities suited to avoid the radars of the time.
The Germans began to use these materials by mid 30’s because the German chemical companies Rohm und Haas AG and Dynamit Nobel AG-Troisdorf were interested in perfecting the plastic sheeting for aircraft use, with the cooperation of the Horten Brothers who, at that time, dedicated to the construction of flying wing sailplanes.
In October 1935, the Horten Ho IIa Habicht flying wing was fitted with a transparent nose made of Plexiglas (polymethyl methacrylate) and Mipolam (polyvinyl chloride) and the wing leading edge was covered with Astralon film (cellulose acetate). Early 1936 one Lippisch conventional sailplane named Hol’s der Teufel was fitted with an experimental wing made of Trolitax DN7019 (plywood sandwich composite with Tronal filling). Tronal, a phenol resin-impregnated corrugated cardboard, was the first synthetic material in the world developed by Dr. Barschfeld of Dynamit AG.
By April 1936 flying tests of the Lippisch sailplane were satisfactory. A weight saving of 15 per cent was realized, with no loss in strength. The success encouraged the Hortens’ to design the first aircraft built of synthetic materials: The Ho Va (W.-Nr. 5) was research flying wing airplane with 14 m span, powered by two 79 hp Hirth HM 60R engines driving counter-rotating pusher propellers. Pilot and passenger lay prone in the nose under Mipolam sheet glazing.
The entire wing structure was made of Dynal Z5 composite, much stronger than Trolitax, the new material consisting of two layers of cardboard reinforced by phenolic resin with a Tronal core. The wing coating was made of Polystal K-10 smooth skin of pressed alternate sheets of Dynal and Tronal that reduced considerably the drag. The propellers were made of Lignofol L90 beech wood impregnated with synthetic resin. Early 1937 the aircraft was destroyed during take-off. Following the accident, Dynamit AG collected the remains to carry out tests of material strength.
After the prototype loss the Hortens’ started the construction of the Parabel flying wing at Aegidienberg, a high-altitude research sailplane with 12 m span parabolic sweptback wing and semi-prone pilot. Theoretically, the continuous curve of parabola might resolve some of the classic aerodynamic problems of swept wings configuration with the minimum induced drag. The prototype was damaged in transit for flight testing in 1938 and burned unflown early 1939 because it was too costly to repair.
The Hortens kept building flying wings for the Luftwaffe during the Second World War. The Ho Vc (W.-Nr.27) a single seat experimental version of the Ho Va. It made its first flight on May 26,1942 and was destroyed in an accident in late summer of 1943. Late in 1943, the Reischsmarshall Hermann Göring awarded 500,000 Reich Marks to the Horten Brothers for aerodynamic research projects.
The Ho VII (W.-Nr. 29) was a two-seat combat trainer with 16 m span, powered by two 240 hp Argus As.10 pusher engines. The aircraft made its first flight in May 1944 at Oranienburg, it was demonstrated to Göring in September 1944 and captured by U.S. troops at Göttingen on April 7, 1945. Two additional Ho VII were under construction at war’s end.
The Ho VIII, propelled by six Argus As.10 pusher engines, was a scale flying model of the Ho XVIII transatlantic bomber project, with 40 m wingspan. Its construction started in 1944 in Göttingen and was to be about 50 per cent complete at the end of the war in Europe.
The secret to the stability of Horten designs was the bell-shaped distribution of lift, harmonizing washout, sweep back, taper, airfoil selection, aspect ratio and CG location. The absence of tailfin in the flying wings produced drag, due to the mittleren effect, an aerodynamic interference between the airflow associated to both wing panels. The Hortens’ mitigated the induced drag using a bat tail configuration in the Ho IX V1 (W.-Nr.38, RLM 8-229). This high-altitude research glider, with 16.76 m wingspan, was built in Göttingen in early 1944.
The prototype was flown on March 1, 1944. Gliding tests were highly satisfactory, directional stability was particularly good and lateral control was good, with extraordinarily little adverse yaw. In the late 1944, one scale model was tested at the supersonic wind tunnel of the Aerodynamische Versuchsanstalt für Segelflug (DFS-Göttingen) showing that the Ho IX could fly at 607 mph (977 kph) powered by two Jumo 004 turbojets.
Unfortunately for the Germans the Ho IX V2 jet-prototype (decades ahead of its time) was destroyed during the third test flight, on March 18, 1944.
It was not until 1940 that the Germans were able to identify the operating frequencies of British radars with the capture of two mobile radar stations at Dunkirk (4 m wavelength) and Chain Home (12 m).
On January 15,1943 the Technical Service of the Luftwaffe concluded that the centimetric wavelengths did not represent a military advantage that justified the effort to obtain them. That would have meant to retire all the available radio technicians from the war front, modify the production lines to manufacture new types of radio lamps, obtain bigger quantities of wolfram from the allied countries and delay the series production of the AI radar Neptun.
On February 2, a Stirling bomber of the Pathfinder Force, that marked targets for an incursion against Hamburg, was shot down by the flak over Rotterdam. The examination of the wreck showed that part of its electronic equipment operated on 9 cm wavelength…..it was one of the first H2S cartographic radars that could be recovered almost intact, as the self-destruction mechanism did not work.
It was based on the cavity magnetron technology, a casual discovery made by J.T. Randall and A. H. Boot in 1940. The German technicians were astonished by the quality of the images received through its small parabolic mirror. Geographical features or even the shape of ships and airplanes could be clearly distinguished at a time when the Lichtenstein SN-2 still operated on 3.30 m.
The German systems of manufacturing still took some time to adapt to the new technology and the overloaded electronic industry was only able to produce ten copies, denominated Berlin N-1, before the end of the war in Europe.
Meanwhile the Allied had been able to break the balance on their favour. The U-Boats were located and destroyed in the darkness, without any reaction from its Metox to the 9 cm. emissions. When the new Naxos were installed, the Allies started to emit on 3 cm and the slaughtering went on. In the air, the Lichtenstein were positioned by the Serrate devices of the Beaufighter and Mosquito and the German IFF was interfered by the Perfectos system.
The Oboe incursions resumed with the help of the 9 cm transmissions, impossible to interfere with the German equipment of the time. On 24 July 1943 the Bomber Command performed a mass attack on the heart of the Reich, using Windows, interference equipment installed in the aircrafts, electronic decoys and long-range escort fighters Mosquito N.F. XII and N.F. XIII. The latest was equipped with nitrous-oxyde boost that also used successfully to catch the Fw 190 and Me 410 night intruders during the Steinbock Operation.
The British defences had been continually reinforced since 1940.
During the first half of 1941 British defenses were strengthened with new types of radars and night fighters.
The 'Chain Home Low' to allow coverage as low of 150 m, the Gun Laying GL/EF (Elevation Finder) used by the Antiaircraft Artillery and the A.I. Mk IV used by Bristol Beaufighters from Squadrons Nos.25, 29, 68, 141, 219, 255, 307, 409, 456, 600 and 604 run by ground Controlled Intercept Stations in Orby, Waldringfield, Willesborough, Durrington, Sopley and Avebury.
Unlike the Chain Home, the G.C.I. system used Type 8 and Type 15 mobile radars, as well as large fixed installations Type 7, which could detect targets over land and identify them as hostile, as their own fighters were equipped with IFF transponders.
In June 1944 they consisted of 100 radar stations, some 2,000 barrage balloons and 2,729 anti-aircraft guns shooting proximity-fuse shells. Many batteries located between Dover and Hastings were equipped with a predictor fire-control radar system.
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You can try to go through http://www.hitechweb.genezis.eu/stealth_intro.htm by @Matej
What about the U-2 Trapeze and Wallpaper projects?
www.cnet.com
Early images of the U-2 spy aircraft being tested at Area 51
Photos, details, and history about the CIA's secret Area 51 testing facility and the U-2 spy planes developed there are showcased in a newly declassified report.
www.cnet.com
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What about the U-2 Trapeze and Wallpaper projects?
Early images of the U-2 spy aircraft being tested at Area 51
Photos, details, and history about the CIA's secret Area 51 testing facility and the U-2 spy planes developed there are showcased in a newly declassified report.
That is RAINBOW
Project KEMPSTER was a method to capture incoming microwaves through absorption by a plasma cloud generated around the aircraft. The problem was that the pilot could be affected by the generated radiation.
Microwaves propagate best along straight lines on an aircraft. A triangular shape without vertical protrusions was judged to be best. The prevailing mythology around the Horten Ho IX continues unabated. I would point out that the Americans captured at least three airframes. If this aircraft was truly a dead end then it should have been scrapped in Germany at the time. There is a credible report of at least one example being flown in the U.S. post-war. The Horten brothers did not want the engines to be exposed in their original design but worked things out with the engines they received. I submit this design was realized in the A-12 Avenger II, which reached the mock-up stage. (See Aircraft Illustrated for April, 2000.)
Microwaves propagate best along straight lines on an aircraft. A triangular shape without vertical protrusions was judged to be best. The prevailing mythology around the Horten Ho IX continues unabated. I would point out that the Americans captured at least three airframes. If this aircraft was truly a dead end then it should have been scrapped in Germany at the time. There is a credible report of at least one example being flown in the U.S. post-war. The Horten brothers did not want the engines to be exposed in their original design but worked things out with the engines they received. I submit this design was realized in the A-12 Avenger II, which reached the mock-up stage. (See Aircraft Illustrated for April, 2000.)
tacitblue1973
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I got you, page 6 for an unfortunately poor image of the PASSPORT VISA. I've found little else myself.
FighterJock
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An excellent find tacitblue1973, and incredibly interesting read too.
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From Paul Suhler, From Rainbow to Gusto : Stealth and the Design of the Lockheed Blackbird
tacitblue1973
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Thanks. I keep hoping somebody has a copy of Skip Holm's 1985 magazine article on the first flight of the U-2 that had extensive use of the radio log between Tony Levier and Kelly Johnson. I was 12 and was instantly hooked on stories of aerospace engineering on the edge by these really skilled and driven people far from home, unable to talk about their work. Quite a few only had a handful of years to be given the the satisfaction their work being publicly acknowledged before passing. And then only partially.
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tacitblue1973
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First place to look which is why I never saw it before haha. Thanks!"Test Outline for Passport Visa"
TRANSMITTAL OF REPORT | CIA FOIA (foia.cia.gov)
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"Test Outline for Passport Visa"
TRANSMITTAL OF REPORT | CIA FOIA (foia.cia.gov)
From the Bahret interviews previously mentioned.
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