Northrop's Flying Wings (2024)

* One of the great dreams of a number of aircraft designers of the 1940s was the "flying wing", an aircraft that consisted only of a wing, providingpure aerodynamic efficiency. The most famous of the flying wings was theseries of test machines and heavy bomber prototypes built by Jack Northrop.This document provides a history and description of the Northrop flyingwings, as well as the German Horten flying wings. A list of illustrationcredits is given at the end.

[1] JACK NORTHROP

[3] XP-79 FLYING WING JET FIGHTER

[5] NORTHROP XB-35

[7] FOOTNOTE: HORTEN BROTHERS FLYING WINGS

[1] JACK NORTHROP

* John Knudson "Jack" Northrop was born in Newark, New Jersey, on 10 November1895. His family decided to move West, and spent time in Nebraska, whichJack regarded as "dreary", being too flat, too cold or too hot, and dull --before moving on to Santa Barbara in South California.

In 1916, Jack Northrop began to visit a local automotive shop run by thebrothers Allan and Malcolm Loughead (pronounced "Lockheed"). The Lougheadbrothers were also tinkering with building airplanes in their shop, andNorthrop was interested enough in what they were doing to be hired on. TheLoughead brothers had very little formal education, and Northrop's knowledgeof algebra and physics made him useful.

After America declared war on Germany in 1917 Northrop enlisted, but the Armyput him to work helping build flying boats instead of sending him intoaction. He mustered out in 1918, went back to working for the Lougheadbrothers at their plant in Burbank, California, in the Los Angeles area. Healso married his high-school sweetheart.

Northrop was intrigued when he learned that the German Albatros fighter had afuselage made of molded plywood, instead of the wood-and-canvas frame commonto aircraft at the time. As a result, Northrop's first airplane, the"Loughead S-1", was built using plywood that had been soaked and forced intoa concrete mold with a balloon, resulting in smooth curves instead of theboxy lines of most contemporary aircraft. However, the market for newaircraft was lousy, and the Loughead company closed its doors in 1920.

Jack Northrop worked for his father's building company for three years as anarchitectural draftsman, but that company folded, too. He then worked foranother little aircraft firm, run by Donald Douglas, helping the companybuild the World Cruiser Aircraft for the US Army, which would fly it aroundthe globe in the spring and summer of 1924.

The World Cruiser Aircraft was of entirely conventional design. Northrop hada strong innovative streak and wanted to do more, coming up with ideas for astreamlined aircraft with a single wing. There was no way it would happen atDouglas, but Northrop was still in touch with Allan Loughead. Loughead hadgone on to work as a real estate developer but wanted to get back intoaviation, and he had potential backing from a Los Angeles venture capitalistnamed Fred Keeler. With Northrop's design in hand, Loughead was able to getthe financial backing from Keeler to start a new company. Keeler, however,not unreasonably insisted that the outfit be named the "Lockheed AircraftCompany" to prevent everyone from stumbling over the pronunciation andspelling of "Loughead".

The new company set up in a rented shop in Hollywood in 1926. The first"Vega", as the new aircraft was called, was ready to fly by mid-1927. Itlooks quaint today, though still elegant in a classic sort of way, but it wasbreathtaking then: all smooth curves except for the radial engine up front,fixed landing gear in teardrop-shaped spats, and a solid high-mounted wing.The wing was unbraced, which made Loughead very nervous, feeling that nobodywould think the aircraft was safe. He tried to push Northrop into addingstruts, but Northrop stubbornly held out.

* Northrop proved right: the good looks and superior performance of the Vegamade it a runaway success. It won air races; it was used by aerialsuperstars such as Amelia Earhart and Wiley Post to set records; and, morepractically, it was a neat and fast six-passenger airliner. Through 1928 and1929, the Lockheed Company could hardly keep up with orders.

Northrop had plenty of clout in the company, and was thinking of improvedderivatives of the Vega with aluminum instead of wood construction, refinedstreamlining, and other new features. However, he had a bigger vision inmind as well: a flying wing. He had grown up in Santa Barbara watchingseagulls and similar soaring seabirds glide through the sky, and found aninspiration in their configuration: mostly wing, a minimal body. What couldbe more efficient than an airplane that consisted of nothing but a wing? Itwould be capable of great range and load capability, since there would benothing in the design of its airframe that would not contribute to lift. Ifseagulls could more or less do it, so could he.

Hugo Junkers in Germany was also interested in the concept of the flying wingand was struggling with designing one that could fly and be controlled.Allan Loughead, unfortunately, was not a believer, and the company had alsohired on a manager who didn't give Northrop a free leash. Northrop only putup with that awkward arrangement for a few weeks and then quit.

George Hearst, son of publishing baron William Randolph Hearst, had bought aVega, and the senior Hearst proved perfectly willing to back Northrop in hisproposed ventures. Northrop established his own company, the AvionCorporation, sited in Burbank, and went ahead with his ideas for a flyingwing, and for a Vega follow-on built of aluminum named the "Alpha" -- in thatorder.

Northrop's first shot at a flying wing had a wingspan of 9.15 meters (30feet) and a single engine with 65 kW (90 HP). "The Wing", as it was known,was built of metal, had fixed "reverse tricycle" landing gear, and twin openco*ckpits, though the right co*ckpit was usually faired over; the pilot didn'thave a windscreen, the belief being that it would interfere withstreamlining. Northrop quickly realized that he was in unfamiliar territoryand that the flying wing was nearly uncontrollable, so he added a twin-boomtail. It was powered by a Menasco Pirate four-cylinder inverted inlineair-cooled engine providing 67 kW (90 HP), originally driving a fixedtwo-blade pusher propeller through a driveshaft. The prop was later moved tothe nose.

First flight was in 1929, with freelance pilot Eddie Bellande at thecontrols; the take-off was from Burbank airport, but the landing was at MurocDry Lake, in the California desert. The aircraft was never given a formalname, being known as the "Northrop 1929 Flying Wing". Apparently it wasscrapped.

That taken care of -- at least for the moment -- Northrop then turned out theAlpha, which performed its first flight in March 1930. It was sold as a mailcarrier, and there were few buyers; only 17 were built, since the Depressionwas setting in and things were difficult. Northrop considered a partnershipwith an aircraft firm in Kansas City, though he was very reluctant to moveback to the Great Plains, and decided instead to cut a deal with DonaldDouglas to set up a "Northrop" subsidiary of Douglas Aircraft in 1932. Hehelped Douglas create the groundbreaking DC-2 and DC-3 airliners.

That was a satisfying accomplishment, and Northrop should have been happywith his life. His home life with his wife and three kids was stable andcomfortable, and he was respected in his work, both for his clear abilitiesand for his modest and conscientious management style. However, he stillwanted more, wanted to be his own boss. Douglas bought out Northrop's sharein the Douglas Company in 1938, turning the Northrop subsidiary into theDouglas El Segundo Division. Northrop decided to strike out completely onhis own, using the cash and some additional backing from financier LaMotteCohu to establish Northrop Aircraft INC in 1939. With war coming, businesswas good, with Northrop winning foreign aircraft sales and contracts to buildsubassemblies for other aircraft manufacturers.

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[2] NORTHROP N-1M & N-9M

* Northrop's real focus in his own company was the flying wing. Working withTheodore von Karman of Caltech, arguable the most prestigious aerodynamicsexpert in the US, in 1940 Northrop flew his first true flying wing, the"N-1M", with "M" standing for "Mockup". Its initial flight was on 3 July1940, with freelance test pilot Vance Breese at the controls.

The "Jeep", as the N-1M was nicknamed, was made of steel tubing and sheathingso it could be easily modified, and in fact its airframe configuration couldbe altered to an extent by ground crew adjustments. It had retractabletricycle landing gear -- all single wheels, the nose gear retracting backwardand the main gear retracting from the wings in toward the fuselage -- and waspowered by twin Lycoming O-145 flat-four air-cooled engines with 48 kW (65HP) each, driving three-bladed variable-pitch pusher propellers. Theaircraft was fitted with a small fixed tailwheel assembly to keep theproptips from scraping the runway on take-off. There was no tailfin. TheJeep originally had downturned wingtips, but it was later modified withstraight wingtips,

The aircraft, in maturity, featured a wingtip control assembly variouslyknown as a "rudderon", "deceleron", or "split flap drag rudder". It was acontrol surface on the rear of the wing near the wingtip that could bedeflected up, down, or split top and bottom to be deflected both ways. Whenone was opened up, it caused the aircraft to turn; when they were both openedup, they acted as airbrakes. The Jeep still had "elevon" control surfacesinboard of the rudderons to provide climb and dive (elevator) or roll(aileron) control.

The N-1M had a length of 5.46 meters (17 feet 11 inches) and a span of 11.8meters (38 feet 9 inches), with a weight of about 1,800 kilograms (4,000pounds). It was painted bright chrome yellow. It proved underpowered, andso the Lycoming engines were replaced by Franklin 0-300 flat-six air-cooledengines with 87 kw (117 HP) each, driving three-bladed propellers. It helpedgive Jack Northrop a handle on how to build a more practical flying wing.The N-1M still survives, on display at the Smithsonian National Air & SpaceMuseum in Washington DC.

* By the end of 1941, America was at war and Northrop was building moreconventional aircraft to support the war effort. The most significantcontribution of the company to the war effort was the big twin-engine P-61Black Widow night fighter, a capable machine though it arrived too late inthe conflict to have a significant influence on the course of events.

Northrop hadn't given up on the flying wing. Even before America entered thewar, the military had given thought to a bomber that could fly across theAtlantic, drop its bombload, and fly back again. If Britain fell to theNazis, such a weapon would be a necessity. The slogan was simple: "10,000pounds of bombs for 10,000 miles" -- 4,500 kilograms for 16,000 kilometers.

[3] XP-79 FLYING WING JET FIGHTER

* While Northrop's main focus was on building the XB-35 bomber, the companyalso went off on other design paths, including a flying-wing fighter. Theoriginal concept was for a rocket-propelled fighter designated the "XP-79" inwhich the pilot flew in a prone position -- partly for streamlining, partlyto handle gee forces, through proper neck support was a difficulty. TheXP-79s were to be powered by a liquid-fuel Aerojet rocket engine providing8.9 kN (905 kgp / 2,000 lbf) thrust, with take-off assisted by twinsolid-fuel "jet assisted take-off (JATO)" boosters providing 4.45 kN (450 kgp/ 1,000 lbf) thrust each.

Three prototypes were ordered in January 1943, with the concept originallyevaluated by unpowered gliders, built of wood with fixed tricycle landing gear-- the nose gear in a spat, the main wheels in underwing fairings -- and awingspan of 9.75 meters (32 feet). They were given the designation of"MX-334". Although Jack Northrop never liked the idea of cluttering up hisclean flying wings with a tailfin, calculations and wind-tunnel work showedthere was no way around fitting one. Three were built, being towed into theair by Lockheed P-38 fighters. One was lost when it got caught in theP-38's propwash and stalled, pilot Harry Crosby bailing out successfully.

One was actually fitted with a prototype Aerojet rocket motor and flew as the"MX-324", but engine development proved troublesome and there may have beenmisgivings about using rocket propulsion anyway -- pure rocket fighters hadblazing performance but pathetic endurance and excessive fire hazard, andwould prove to be a very bad idea. The decision was made to not build two ofthe rocket-powered XP-79 prototypes; the third was to be built with twinWestinghouse J30 (19-B) turbojets.

The result was the "XP-79B", definitely one of the most unusual aircraftflown during World War II. It retained the prone pilot position of thegliders, but added retractable landing gear, in a "quadracycle"configuration, four wheels in a "baby buggy" configuration; twin tailfins;and a Westinghouse J30 engine in a nacelle on each side of the co*ckpit, witheach engine providing 6.1 kN (620 kgp / 1,365 lbf) thrust. Wingspan was11.6 meters (38 feet) and take-off weight was 3,930 kilograms (8,670 pounds).

The XP-79B had a puzzling little inlet on each wingtip, which provided ramair to a bellows to help actuate the rudderons. The pilot flew the aircraftwith a crossbar handle and foot pedals. Armament was to be four12.7-millimeter (0.50-caliber) Browning M2 machine guns in the wing leadingedge, though it wasn't fitted in the prototype.

One of the particularly odd features of the XP-79B was the notion that itwould be used in ramming attacks on enemy aircraft. The originalspecification never mentioned the idea, and it was preposterous on the faceof it -- trying to execute a ramming attack without damaging the canopy,tailfins, and engines might be very tricky, and there was no sense in gettingany closer than needed to a target's defensive armament anyway. Eventraining to perform such attacks would be problematic, and no pilot wouldhave resorted to ramming as anything but an act of desperation.

However, Jack Northrop himself stated: "It was designed as a projectile,with the thought that it could be used to intercept and knock wings or tailsoff other airplanes." Where this dubious notion came from is unclear -- theaircraft was built strong and possibly some engineer, maybe Northrop himself,suggested it could be used in ramming attacks, and threw it out asmarketing hype. If the concept was taken seriously at Northrop, it seemsunlikely that USAAF brass thought much of it.

The XP-79B was hauled out to Muroc Dry Lake (now Edwards Air Force Base) inJune 1945, to perform its first flight on 12 September 1945, with HarryCrosby at the controls. It was also its last: the aircraft flew fine forabout 15 minutes, then went into an unrecoverable spin. Crosby managed toget out, but his parachute didn't open fully and he was killed. Although thecause of the accident was determined and was fixable, by that time the USAAFhad lost interest in the program and that was the end of it.

While it seems unlikely that the XP-79B would have ever gone to production,even disregarding the tragic death of Harry Crosby it was a pity it didn't gothrough full trials. Practical or not, no aircraft looked more like a 1940sscience-fiction prop, and video footage of the thing flying around would befascinating.

Northrop also worked on a series of flying-wing cruise missiles, the "JB-1"and "JB-10", using a manned glider (with upright seating this time) as ademonstrator, once again towed into the air by a P-38. This topic isdiscussed in more detail in a companion document on cruise missiles.

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[4] XP-56 & X-4

* Along with the XP-79, Northrop also developed two "tailless" aircraft --with a fuselage, wings, a tailfin, but no tailplane. The first began withArmy Air Corps "Request for Proposal R-40C", issued in 1940, specifying afast, high-altitude, long-range interceptor, with vendors encouraged to"think out of the box". Northrop engineers had already been thinking out ofthe box, and returned a proposal for a tailless fighter with a pusher engine;the Air Corps like the proposal, and funded a flight prototype. A secondprototype would follow later.

The XP-56 had a short, blunt fuselage, with a pusher prop driven by a Pratt &Whitney R-2800 28-cylinder two-row air-cooled engine providing 1,500 kW(2,000 HP). The prop was contra-rotating, with three variable-pitch bladeson each prop stage; the engine intakes were in the wing roots. It wassupposed to be powered by the P&W X-1800 24-cylinder H-block liquid-cooledinline engine, but it didn't materialize; using the radial engine meant abigger fuselage. The aircraft was 8.38 meters (27 feet 6 inches) long, had awingspan of 12.96 meters (42 feet 6 inches), and an empty weight of 3,955kilograms (8,700 pounds).

The XP-56 had inverted gull wings, a dorsal tailfin -- in part to keep theprop off the runway -- and a small ventral tailfin. It had the wingtipinlets like the XP-79; they were actually developed for the XP-56. Itfeatured retractable tricycle landing gear, all gear assemblies with singlewheels, main gear tucking in from the wings towards the fuselage, nose gearretracting backward. The XP-56 was built of magnesium alloy, apparently outof fear of aluminum shortages. It was to be armed with twin 20-millimetercannon and four 12.7-millimeter (0.50-caliber) Browning M2 machine guns, butit is not clear if the prototypes were ever fitted with armament.

Initial flight of the first prototype, tailcode 41-786, was on 30 September1943, with the aircraft demonstrating bad yaw instability; the ventraltailfin was enlarged to about the same size as the dorsal tailfin, solvingthis problem. The first prototype was damaged beyond repair on 8 October1943 when a tire blew out during a high-speed taxi run; the pilot, JohnMyers, survived without serious injury.

The second prototype, tailcode 42-38353, flew on 23 March 1944. It featuredsome changes in ballasting, a larger ventral tailfin, and modified ruddercontrol. It could not reach design speed and handling was difficult; it onlyperformed ten flights before the decision was made that the XP-56 was unsafeto fly, with the program abandoned a year later. The second prototype endedup in the hands of NASM, but hadn't been restored at last notice.

* Although the XP-56 was a dead end, the USAAF awarded a contract to Northropin 1946 to build two prototypes of a tailless jet research aircraft, with thefirst "X-4 Bantam" flying on 15 December 1948 from Muroc Air Force Base inCalifornia -- Charles Tucker at the controls. It was a small aircraft ofall-metal construction with a stubby fuselage, swept wings, a tailfin, andretractable tricycle landing gear -- all gear with single wheels, the maingear retracting from the wings towards the fuselage, the nose gear retractingbackwards.

The X-4 was powered by twin Westinghouse J30-WE-7 / WE-9 turbojets with 7.1kN (725 kgp / 1600 lbf) thrust each. It had split flaps that also worked asair brakes. The bubble canopy hinged up from the rear. Length was 7.09meters (23 feet 3 inches), wingspan was 8.18 meters (26 feet 10 inches), andempty weight was 2,500 kilograms (5,510 pounds).

The idea behind the X-4 was that the wing and the tailplane did not play welltogether at transonic speeds, leading to flight instability, and so it seemedto make sense to get rid of the tailplane. The first prototype turned out tobe unreliable, and only flew ten times before it was grounded, to bescavenged for the second prototype. It was flown from 1950 to 1953 by theHigh-Speed Flight Research Station of the National Advisory Committee forAeronautics (NACA), the principal ancestor of the modern National Aeronautics& Space Administration (NASA).

[5] NORTHROP XB-35

* Work on the XB-35 flying-wing bomber continued through World War II, if ata slow pace. The payload-range requirement in the original USAAF request wasunreasonable -- it would be hard to do even today -- and as the war turnedagainst the Axis, the need for a trans-Atlantic bomber faded. However, theproject didn't die out.

The first XB-35 prototype performed its initial flight on 25 June 1946. Thefirst rival "XB-36" followed in August, and appeared less promising. It didnot appear capable of meeting its design goals, and Convair -- asConsolidated had become after merging with Vultee during the war -- foundgetting the aircraft on track difficult.

The second XB-35 prototype performed its initial flight on 26 June 1947. Asthe XB-35 emerged, it was a huge flying wing, built mostly of aircraftaluminum and driven by four Pratt & Whitney (P&W) R-4360 air-cooled,four-row, 28-cylinder radial engines, each driving a pusher propeller througha driveshaft and providing a maximum of 2,240 kW (3,000 HP). TheHamilton-Standard propellers were of contra-rotating configuration, with eachstage featuring four blades. There were wide slot engine intakes in theleading edge of the wing.

The wing featured rudderons at the tips, a flap on each wing between theengines, a wider "elevon" control surface outboard of the engines, and a slotin the outer front top of the wing that closed or opened automatically.Controls were actuated using a dual-hydraulic system; an "artificial feel"system monitored the elevons to give the pilot feedback. There were notailfins. Landing gear was of tricycle configuration, all electricallyactuated, with twin-wheel main gear in the wing between the inboard andoutboard engines retracting forward, and single-wheel nose gear retractingsideways to the left.

Normal crew was nine, including a pilot, copilot, bombardier, navigator,engineer, radio operator, and three gunners. There were folding bunks to therear for six relief crew for long missions. The pilot sat in a bubble canopyoffset to the left of the aircraft's centerline, with the copilot sittingwithin the wing to the right, seeing out through glazing in the wing leadingedge. The bombardier sat to the right of the copilot, aiming through aglazing beneath the wing. Radio operator, flight engineer, and navigatorwere in a compartment to the rear, with an astrodome on top for the navigatorto take sextant readings.

Defensive armament consisted of 20 guns in seven remote-control positions --a two-gun turret above and below each wing, a four-gun turret above and belowthe center section, and a four-gun tail stinger. The guns were all BrowningM2 machine guns, though apparently there was consideration of using20-millimeter cannon in production. There were crew sighting bubbles on therear fuselage for the guns, though neither XB-35 was ever armed. There werefour separate bomb bays in each wing -- three inboard of the main gear welland one outboard -- with a maximum total bombload of 23,675 kilograms (52,200pounds).

___________________________________________________________________ NORTHROP XB-35: ___________________________________________________________________ wingspan: 52.4 meters (172 feet) wing area: 371.8 sq_meters (4,000 sq_feet) length: 16.18 meters (53 feet 1 inch) height: 6.1 meters (20 feet) normal loaded weight: 73,470 kilograms (162,000 pounds) max speed at altitude: 630 KPH (390 MPH / 340 KT) service ceiling: 12,195 meters (40,000 feet) range: 12,075 kilometers (7,500 MI / 6,520 NMI) ___________________________________________________________________

The two XB-35s were built, but they proved unsatisfactory. The contrapropsand the drive system were very unreliable, leading to their grounding bySeptember 1947. They were refitted with ordinary four-bladed propellers andreturned to the air in early 1948. The new props helped a lot with themechanical problems -- but the props couldn't provide adequate powertransfer, and performance suffered. Only one YB-35 was completed, performingits initial flight on 15 May 1948. Unlike the XB-35s, it was fitted withdefensive armament.

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[6] NORTHROP YB-49 & YRB-49A

* Along with two XB-35s and the single YB-35, 12 more B-35-type flying wingswere planned, though none would fly as B-35s. The USAAF was losing interestin piston bombers, jet aircraft being clearly seen as the way of the future.In late 1944, Northrop had proposed a jet derivative of the B-35, to bedesignated the "B-49". Two of the planned flying wings were accordinglybuilt as "YB-49" prototypes -- originally to be designated "YB-35B" -- thefirst performing its initial flight on 24 October 1947. It was followed by asecond YB-49, which performed its initial flight on 13 January 1948.

The general dimensions of the YB-49 were of course identical to those of theXB-35. It was powered by eight Allison J-35A turbojet engines, with theengines arranged in parallel quads in each wing and intakes in a slot in thefront of the wing. Yaw stability was more of a problem with the YB-49 thanit was for the XB-35, and so the jet flying wing had four tailfins,protruding above and below the wing, with a tailfin inboard and outboard ofeach engine array, and a long "fence" in front of each tailfin on the top ofthe wing. All the defensive armament except the tail stinger was deleted.The fuel-hungry jet engines cut range, and warload was reduced to 14,510kilograms (32,000 pounds).

___________________________________________________________________ NORTHROP XB-49: ___________________________________________________________________ wingspan: 52.4 meters (172 feet) wing area: 371.8 sq_meters (4,000 sq_feet) length: 16.18 meters (53 feet 1 inch) height: 4.63 meters (15 feet 2 inches) normal loaded weight: 87,955 kilograms (193,940 pounds) max speed at altitude: 795 KPH (495 MPH / 430 KT) service ceiling: 12,410 meters (40,700 feet) range: 5,080 kilometers (3,155 MI / 2,745 NMI) ___________________________________________________________________

Some sources claim that pilots found the YB-49 elegant to fly -- though othersources point to its instability, it being too much like a boomerang to flyvery straight. The public found the flying wing design fascinating andpopular science magazines played it up as the "aircraft of the future".Unfortunately, the second YB-49 was lost in a crash on 5 June 1948, all thecrew being killed. It turned out the aircraft had suffered a structuralfailure in a dive test. Muroc AFB was subsequently renamed "Edwards AFB"after the late pilot, Captain Glenn Edwards.

* Despite the accident, the flying wing did seem to have a very promisingfuture. Late in June 1948, Jack Northrop was visited by US Air Force GeneralJoseph McNarney, a big cheese in the USAF procurement hierarchy, and gave himan order for 30 "RB-49A" reconnaissance machines. McNarney assured Northropthat large numbers of orders would follow. A single "YRB-49A" machine wasbuilt, differing from the YB-49s in having no tail stinger, and reducing thenumber of engines to six -- with four in the wing itself and two mountedunder the wing on pylons. Jack Northrop hated tacking on the engines underthe wing, but it freed up space in the wing for fuel tanks, particularly bytrimming back on the complicated wing ducting. It performed its initial flight on 4 May 1950.

By that time, the program had run into fatal turbulence. Since Northropdidn't have production facilities adequate to build the RB-49A in quantity,it was to be built in the Convair plant in Fort Worth, Texas, which was ownedby the government. It might have been satisfying for Northrop to realizethat his rival, Convair, would not only lose the contest but would have tosupport flying wing production, but that blade cut both ways. Coming to anagreement with Convair on production proved troublesome; and then on 16 July1948, Secretary of the Air Force Stuart Symington bluntly told Northrop thathis company had to merge with Convair.

The two companies couldn't agree on a merger either, and then things beganto go from bad to worse for Jack Northrop. The B-36 was finallydemonstrating most of the range and payload for which it had been designed.The flying wing, in contrast, was still not meeting its range specifications,and its thick wing ensured that its performance would always be limited. TheAir Force had only turned to the flying wing when the B-36 program appearedto be close to collapse; when it revived, the B-49 didn't have a chance.

In early 1949, Symington ordered increased production of the B-36. Sincemoney was tight, that meant killing other projects. On 11 January 1949, theflying wing was canceled. There was something of a scandal over thedecision, with critics charging that Symington's actions were part of a plotto build an aviation super-company that he would eventually lead. There werehearings over the matter in August 1949. There was no evidence to supportany of the charges and the issue was dismissed, permanently.

Jack Northrop continued to insist that Symington had been up to no good,cancelling the RB-49A when Northrop didn't go through with the merger withConvair. There was no evidence to support this accusation, and in fact inMarch 1949 the Air Force had given Northrop a big contract to build the F-89Scorpion all-weather interceptor. With the Cold War slowly brewing up,Symington needed to improve America's strategic defense posture as quickly aspossible, and if that meant stepping on the toes of people like JackNorthrop, that was just too bad. In any case, the Air Force was alreadyacquiring much faster bombers like the Boeing B-47, capable of speeds thatthe B-49 could never touch.

Nine unfinished flying wings -- most of which were to be completed to RB-49Aspec, with a few to be used for trials -- were scrapped, as were thesurvivors of the six that flew. Tragically, none of them ended up in an airmuseum. The whole fiasco took the wind out of Northrop. In November 1949,all 11 of the flying wing bombers that had been built were scrapped --except for the first YB-49, which had been destroyed in a fire after a groundaccident on 15 March 1950. Tragically, none of the flying wing bombers wentto air museums. He divorced his wife, and in 1952 he resigned from thecompany even though he was only 57 and business was good.

* Jack Northrop would, in the end, receive some vindication. In April 1980,after he had been left mute by a stroke, he was driven to a secret office atNorthrop and shown plans for a new aircraft in the works: the B-2 stealthflying wing bomber, to be built by Northrop. He died some months later andnever got to see it fly, but it was a satisfaction to know that his workhadn't been forgotten after all.

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[7] FOOTNOTE: HORTEN BROTHERS FLYING WINGS

* The flying wing configuration was very attractive to aircraft designers inthe 1940s. It seemed to promise a highly efficient aircraft, since the formof the aircraft included little that did not provide lift.

Jack Northrop's German counterparts were the Horten brothers, Reimar andWalter. They developed a series of gliders and powered aircraft to testtheir flying wing concepts, including:

Ho I (1st flight 1933 / 1 built): A pure flying wing glider.
Ho II Habicht / Hawk (1935 / 4): Improved glider, one with pusher prop.
Ho III (1938 / 19): Improved Ho II.
Ho IV (1941 / 4): Glider with prone pilot & long "boomerang" wing.
Ho V (1937 / 2): Motorglider with twin pusher props, 1 or 2 seats.
Ho VI (1944 / 2): Improved Ho IV.

From 1936, the Hortens were both Luftwaffe officers, in which capacity theycontinued their interest in flying wings. In 1942, they came up with aconcept for a flying-wing jet fighter. They began by building a trainer, the"Ho VII", which had dual controls and two 180 kW (240 HP) Argus air-cooledinverted-vee As-10 piston engines, driving pusher propellers. Two werebuilt. Since the Hortens were performing this development on their owninitiative and without RLM approval, they formally described the Ho VII as a"research aircraft", which had enough truth in it to be not quite a completelie. Incidentally, the Hortens also worked on an "Ho VIII", with ambiguousdescriptions in the literature, but in any case it wasn't flown.

The actual fighter design was designated the "Ho IX". The Hortens had showndrawings of their flying-wing fighter to Reichsmarshall Hermann Goering, andthey had his personal backing for the project. The first prototype of theHo-IX, the Ho IX V1, was originally built as an unpowered glider, firstflying in 1 March 1944. By May, the potential of the Ho IX was apparent, andthe RLM had authorized development, ordering more prototypes and 20production aircraft. Manufacturing was assigned to the Gotha company, andthe production fighter was to be designated the "Gotha Go 229".

Some sources claim the Ho IX V1 was later fitted with twin BMW 003 engines,but in any case it was lost in a crash later in 1944. Work on thesecond prototype, the powered Ho IX V2, was delayed because the requiredJunkers Jumo 004B engines were not available, and the Ho IX V2 did not flyuntil just before Christmas, 1944. It only logged two hours of flight timebefore it crashed on 18 February 1945.

Work on the Ho IX V3, which was closer to production spec, moved slowly dueto economic dislocations caused by Germany's military collapse. While theengines of the Ho IX V2 were smoothly buried in the wings, the engines onthe Ho-IX-V3 protruded up through fairings on top of the wing.

The Ho IX V3 was almost complete when US forces occupied the factory, andwas shipped to the Smithsonian Air & Space Museum, where it resides today.The V4 and V5 prototypes were intended for development of a two-seatnight-fighter variant that was not built. The V6 prototype was theproduction prototype for the Go 229 day fighter variant, with much externalresemblance to the V3, but considerable re-engineering under the skin.

The Go 229 was a pure flying wings. The center section was framed with steeltubing, the wings were of wooden construction, and the entire aircraft wasskinned in plywood. Some components were made out of a wood composite named"Formholz", which was something like particle board molded to specific shapesunder pressure. The Go 229 featured tricycle landing gear, and the co*ckpitwas fitted with a crude ejection seat. It was to be armed with four MK 103or MK 108 30-millimeter cannon and would be able to carry two 1,000-kilogram(2,200-pound) bombs.

The Go 229 was to have a wingspan of 16.8 meters (55 feet), a length of 7.47meters (24 feet 6 inches), an empty weight of 4,600 kilograms (10,140pounds) and a fully loaded weight of 8,100 kilograms (17,860 pounds).Performance was estimated at 970 KPH (600 MPH) at 11,900 meters (39,000feet). Range was expected to be a remarkable 1,900 kilometers (1,180 miles)without drop tanks, or 3,170 kilometers (1,970 miles) with drop tanks.

* The Hortens considered a supersonic delta rocket-jet fighter, the "Ho X",but only got as far as building a pusher-prop demonstrator that was nevercompleted. They did fly a single demonstrator glider, the "Ho XIII", toevaluate a highly-swept flying wing configuration, with a pilot's gondolatacked on under the rear of the wing.

In addition, they drew up designs for a huge bomber flying wing, the "HoXVIII", with enough range to fly to America, hit New York or Washington with4 tonnes (4.4 tons) of bombs, and return to Germany. The RLM issued arequirement for an "Amerika Bomber" in 1944, with five companies providingdesigns, none of which were acceptable. The Hortens weren't invited tosubmit a design, the perception being that they were focused on fighters, butwhen they learned about the Amerika Bomber competition very late in 1944,they came up with a proposal for a big flying wing designated "Ho XVIIIA",made mostly of nonstrategic materials and powered by various enginearrangements, such as eight Jumo 004B turbojets buried in the center of thewing.

The flying wing configuration promised aerodynamic efficiency and lots ofspace for fuel tanks, making it possible for a jet-powered aircraft to meetthe range requirement in an era when jet engines were notorious fuel hogs.The Hortens pitched their design to the RLM in February 1945 and RLMofficials were very interested -- but they then handed the design over to acommittee of aircraft designers from other firms, who added such things as atailfin and moved the engines beneath the wing.

The Hortens were appalled since such changes reduced the aerodynamicefficiency of the aircraft, and came up with their own "Ho XVIIIB" designthat swallowed some of the concerns of the RLM to give a solution more on theHorten's own terms. The Ho XVIIIB was to be a flying wing with fixed landinggear in the form of a pylon-like fairing under each wing that featured fourwheels in series; the wheels were covered by aerodynamic doors in flight. Asingle Heinkel-Hirth HeS 011 turbojet was fitted on each side of both landinggear fairings, giving a total of four engines.

The three crew sat under a single bubble canopy in a pressurized co*ckpit.There was to be no defensive armament, the aircraft obtaining protection fromspeed and altitude -- even if a fighter could reach its altitude, the flyingwing, with its huge wing area, would be easily able to outmaneuver it. TheHortens did provide variant designs with defensive armament in case the RLMinsisted.

As envisioned, the Ho XVIIIB was to have a loaded weight of about 35 tonnes(38.5 tons), a span of 40 meters (131 feet 4 inches), a top speed of 850 KPH(528 MPH), a ceiling of 16,000 meters (52,500 feet), and a range of 11,000kilometers (6,835 miles). It was an impressive idea, but like many ofGermany's last-gasp weapons, was nothing more than a paper fantasy. OtherGerman aircraft manufacturers considered flying-wing designs, but none ofthem ever came to anything, either.

* Reimar Horten emigrated to Argentina after the war, where he continuedto design gliders and powered aircraft. He died there in 1994. Walterstayed in Germany, becoming an officer in the revived Luftwaffe, and diedthere in 1998. The Hortens have acquired something of a legendary status, asvisionaries far ahead of their time -- with many comments about the"stealthiness" of their designs, just as with Jack Northrop. In reality,while they were ingenious, in practice they were tinkerers, who made nomajor contributions to aircraft design.

BACK_TO_TOP

[8] COMMENTS, SOURCES, & REVISION HISTORY

* Neither the Northrop nor Horten flying wings amounted to much, but theflying wing is alive and well in the 21st -- most spectacularly in the formof the B-2 Stealth bomber and its follow-on B-21 Raider bomber. It is alsocommon among drones, and efforts are currently under way to develop"blended-wing body" aircraft that are clearly evolved from flying wings.Flying wings have become more practical because of improved aerodynamicknowledge, advanced airframe materials, and in particular very smartfly-by-wire control systems. However, modern flying wings are another story.

* Sources include:

THE FLYING WINGS OF JACK NORTHROP by Garry R. Pape with John M. & Donna Campbell, Schiffer Military / Aviation Books, 1994.
"The Dream Of The Flying Wing" by Tom A. Heppenheimer, INVENTION & TECHNOLOGY, Winter 1994, 55:63.
"Northrop's Flying Wings" by Bill Gunston, WINGS OF FAME, Volume 2 / 1996, 24:37.

* Illustration credits:

Northrop YB-49 / Northrop
The Wing / Northrop
Northrop N-1M / Smithsonian NASM, VA USA / 2004 / author
Northrop N-9MB / Chino Airshow 2014, CA USA / Tim Felce (Airwolfhound) / Creative Commons Share Alike License
Harry Crosby with MX-334 glider / Muroc CA USA / 1944 / Northrop
XP-79B / USAAF?
XP-56 / USAAF?
Northrop X-4 / USAF
XB-35 / Northrop?
XB-35 / Northrop?
YB-49 / Northrop
YB-49 / artist unknown
YRB-49A / Northrop
unfinished flying wings / Northrop
Horten Brothers aircraft / drawing by author
Ho IX v1 glider / author unknown
Ho IX v2 glider / author unknown
Go 229 / Revell models
Ho XVIIIb / flightsim by BorekS
X-48B BWB drone demonstrator over Edwards AFB range / 2007 / Carla Thomas, NASA

* Revision history:

Northrop's Flying Wings (2024)

References