Chasing Mercury - The Northrop N-227

One of the requests that Diane made when I started doing monthly articles for her was to cover space related projects. This was because our sector includes the former TRW, which has an incredible space history.

Fortunately, I also had a strong interest in that subject, so the request was not a hard one to fulfill. I am, after all, a child of the space age. But I remain a heritage Northrop guy and even though I greatly appreciate the history of Grumman, Ryan, Radioplane, TRW and Scaled Composites, any chance I get to explore Northrop legacy programs and proposals I will do so in a heartbeat.

This is not to say I won't explore the other heritage companies' histories - I have and I will continue to do so and they will eventually be posted here. But availability is also a key and I have had much more success with finding Northrop history than with the other companies, save perhaps Ryan.

The Mercury Program is of special signifcance to me. I remember my mother waking me in the early morning to watch Alan Shepard's suborbital flight and later John Glenn's launch and three-orbits around the Earth. Nearly twenty years later the circle would close as I roused my six-year old daughter to watch Columbia make the maiden voyage of the shuttle program into space. Perhaps someday she can watch a launch to Mars with her kids in the wee hours of the morning.

One final note: I did manage to find some information on the Grumman G-214, their Mercury proposal. Be on the lookout for it in the next few days.

This article was originally published in the Northrop Grumman Engineering Department in-house, on-line magazine Airspace, vol. 2, no. 6, in April 2011. It is re-posted here with permission and has approved for public release case number 12-1474.      

Chasing Mercury – The Northrop N-227

By Tony Chong

April 12, 2011 marked the 50^th anniversary of the launch of Vostok 1.  On that day in 1961 Soviet cosmonaut Yuri Gagarin became the first human to go into space.  He also became the first human to orbit the Earth.

Twenty-three days later, on May 5, 1961, Alan Shepard became the first American astronaut to go into space during a 15 minute, 28 second sub-orbital flight that took him 303 miles downrange from the launch site at Cape Canaveral, Florida.  Shepard rode inside a Mercury capsule fitted to a U.S. Army Redstone missile. 

Project Mercury, America’s first series of manned spacecraft, was a program designed to put an American into space as quickly as possible.  It was not, however, a hastily conceived stop-gap measure.  In actuality the ballistic manned satellite concept was one of three methods under active consideration by the U.S. Air Force since 1956 for establishing an American presence in space, with the initial phase eventually being called “Man In Space Soonest” and the fourth and last phase to encompass a manned lunar landing fifteen years after program start. 

Sputnik’s launch on October 4, 1957 changed all of the dynamics in the blossoming American space program.  Faced with a need to respond to the Soviet initiative, and with a desire to curb military expansion into space, President Dwight Eisenhower threw his weight behind a civilian-controlled agency.  The important, but obscure National Advisory Committee for Aeronautics was remade into the National Aeronautics and Space Administration, effective October 1, 1958.

NACA had itself examined the three basic types of manned spacecraft – ballistic, skip and glide – prior to Sputnik.  For a variety of good reasons (launcher capabilities and developmental issues, among others), the new NASA chose the ballistic approach.  McDonnell Aircraft Corporation won the competition to build the capsule, but what is largely forgotten is that heritage Northrop Aircraft, Inc. competed for that program as well.

Northrop was one of the eleven aircraft manufacturers that responded to the Air Force’s 1956 request to industry for manned satellite concepts.  As late as January 1958 the company (which changed its name to Northrop Corporation on February 2, 1959) adhered to the more sophisticated “boost-glide” vehicle proposal, the basis for the eventual X-20 Dyna-Soar (Dynamic Soarer) program won by Boeing in June 1959.  However, with NASA issuing a specification on November 14, 1958, for a ballistic capsule, Northrop answered with a design that carried the internal designation N-227.

NASA’s specifications included the need to fit the capsule to both the Redstone missile (for sub-orbital flights) and the Air Force/Convair Astronautics Atlas missile (for orbital missions).  Additional requirements for a launch-escape rocket tower system, a retro-rocket system for de-orbiting, a zero-lift body utilizing blunt-end re-entry for drag braking, pilot controllability of the capsule and the ability to land in water also drove the basic shape of the design.

Northrop’s proposal was very similar to the winning McDonnell vehicle.  The main visual differences were in the wider diameter at the blunt end for the Northrop craft – 80 inches versus McDonnell’s 74.5 inches – and the shape of the forebody of the capsule. 

The launch-escape rocket tower structure also differed in where it attached to the two proposals.  Northrop’s craft featured a constant-diameter forebody with the tower joined to the flat end (top) of the vehicle.  McDonnell’s design had a tiered forebody with the tower structure fitted over the smaller diameter upper section.

Both designs also featured a corrugated look to the capsule exterior surface.  However, Northrop’s corrugations ran along the length of the vehicle while McDonnell’s formed around the circumference of the craft.

Final designs on this fast-tracked proposal were due by December 11, 1958.  The NASA selection team worked over the Christmas holidays to determine the winner.  Northrop did not make the final cut. 

Ironically, heritage Grumman, a late entry into the manned spaceflight game, did.  It essentially tied with McDonnell as having the best design.  However, because Grumman was deemed to be short on manpower due to some impending Navy contracts, the award was given to McDonnell on January 12, 1959. 

Alan Shepard would make his historic flight just two years and four months later.

 

Kristi Harding of Records Management contributed to this article.

Any information on the Grumman Mercury proposal would be greatly appreciated by the author for incorporation in a possible future article.

For further reading, check out “This New Ocean – A History of Project Mercury” by Swenson, Grimwood and Alexander, NASA SP-4201 in the NASA Historical Series, U.S. Government Printing Office, 1966.

For “Man-In-Space-Soonest” background information, check out: http://www.astronautix.com/fam/manonest.htm

On-line information on Project Mercury can be found at: http://www-pao.ksc.nasa.gov/history/mercury/mercury.htm and http://www.thespacereview.com/article/586/1

Tony Chong is a historian, photographer and a contributing editor to Airspace. He leads activities in the Aerospace Systems Display Model Shop and works in El Segundo.

 

Photo Captions

 

1) N-227 3-view: This 3-view drawing taken from the Northrop proposal shows the basic layout of the N-227 design.  Note the shape of the forebody, the attachment of the launch-escape rocket tower and the diameter of the blunt end of the spacecraft.  The head-on view shows the linear corrugations on the skin.  Photo credit: Tony Chong collection 

 

2) McDonnell 3-view: By comparison this general arrangement 3-view drawing of the McDonnell capsule, taken from one of its proposal pages, shows a tiered forebody, a narrower diameter in the widest part of the capsule proper (the adapter shroud flares out more) and a different method of attaching the tower structure to the spacecraft.  Photo credit: Tony Chong collection 

 

3) N-227 stats: Another page from the Northrop proposal features a weights and balance breakdown of the various components of the company’s design.  Photo credit: Tony Chong collection

 

4) img066: Northrop’s proposal featured an artist’s concept painting of the N-227 in the splashdown/recovery phase.  The linear corrugations show up well in this interpretation, as does the inflated orange, torus-shaped landing impact airbag with an internally-fitted stabilization water bag.  The artist’s signature says “Todd.”  Photo credit: Tony Chong collection

 

5) 158209: Several photos were taken of a small model of the N-227 showing how it would have looked mounted on a Redstone or Atlas missile.  This particular image shows the rather ungainly looking transition fairing and how it would have joined to the Redstone missile.  Photo credit: Northrop Grumman

6) mr-2: Contrast the previous image with this of the McDonnell Mercury capsule fitted to the Redstone missile.  Even with the slight overhang, the smaller diameter of the McDonnell design makes for a much cleaner fit to the launcher.  Photo credit: NASA 

7) 158208: This image shows the model of the N-227 separated from the Redstone launcher.  The combined fairing, capsule and launch-escape rocket tower assembly sitting next to the Redstone body gives a good indication of the relatively small size of the missile, as if emphasizing that it was only powerful enough for sub-orbital flights.  Photo credit: Northrop Grumman

 

8) 158206: The fairing on the N-227 and how it joins to the Atlas missile is shown in this photo.  Note the inverse taper from the capsule’s 80” diameter body to the smaller diameter top of the Atlas.  Photo credit: Northrop Grumman

9) GPN-2003-00042w: Again, the contrast between the Northrop proposal and the actual Mercury/Atlas combination is noticeable.  While still featuring an inverse taper, the McDonnell fairing is much shorter than the N-227’s.  An obvious question would be did the taller fairing and wider capsule, with perhaps its potential vibration and/or stability problems along the transition structure, play a part in Northrop’s loss?  Photo credit: NASA

10) 158207: The N-227, with its tower and fairing, is shown separated from the Atlas booster.  The hand is a good indicator of the size and scale of the model.  Photo credit: Northrop Grumman

Northrop's Lost Tracker - The N-60

Much like the evolution from vinyl to tape to CD to the cloud, advances in technology always make for that awkward moment when you realize your "state-of-the-art" reproduction tools in one era are pretty much antiquated in another. 

And so it is with the N-60 data. Originally reproduced on a copy machine in the early 1990s, I had the opportunity to get the brochure back for a short time and was able to take some digital images about eight years later. 

What I would have given to have had a nice scanner back in those days.

Nevertheless, we do what we can with the tools we have available at the time. Perhaps another day I will get a third chance.

This was a particularly intriguing subject to me mainly because Northrop proposals for Navy programs are not well known. The fact that a primarily Army and Air Force contractor would pursue carrier-based aircraft raises all sorts of issues for that company, especially in understanding the environment in which those aircraft operate. In short, it ain't as easy as it looks, and it doesn't really look easy to begin with.

A couple of comments before we proceed: When I wrote the caption to image number 8, I knew I had seen a photo of a twin-engine prop aircraft in that angle before. While there is indeed one of the AJ-1 Savage in just such a position, as noted, the photo I was really thinking of was one of the Lockheed P2V Neptune, which was taken shortly before the artist's concept was done. I, of course, unearthed it after the article went to publication.

It is, of course, logical to say that all images of a twin-engine prop airplane taken or drawn from that vantage point would look similarly dramatic. However, I'm fairly convinced that this particular piece of art was deliberately fashioned after the Neptune photo in order to generate a more visceral reaction within the Navy customer examining the proposal. The survival of Naval aviation was being fought over in the Pentagon and in Congress at that time and a strong emotional appeal could only help sell the product. As Northrop was a very dark-horse in the competition, it would need all the help it could get. Or so, I'm betting, the thinking went.

This article was originally published in Airspace Vol. 3, No. 16, March 2012. It is posted here with permission and has approved for public release case number 12-1493.

With that said, let's take a look at the N-60. 

Northrop’s Lost Tracker – the N-60

By Tony Chong

The demands of naval carrier aviation have always presented tough challenges for those willing to build airplanes for that service.  It is a difficult field to compete in and even more difficult for an inexperienced company to win against established opponents.

The rapid advancement of aircraft design in World War II, followed shortly by the start of the Cold War and the transition from the piston age to the jet age, offered a multitude of opportunities for unproven companies to make that breakthrough.  One such opening occurred in 1949 when the Navy’s Bureau of Aeronautics (BuAer) issued an Outline Specification inviting the industry to bid on a new type of aircraft. 

OS-117, as it became known, sought to replace the existing Hunter/Killer teams then in service with a single, self-contained platform that could detect, identify, track and destroy enemy submarines in an ocean environment and in all weather.  Additionally it was to be operable from all of the Navy’s carriers, ranging from the small CVE-105 class escort carrier all the way up to the very large CVB-41 class battle carrier.

Eighteen companies responded with a total of 24 proposals.  Among them was one from heritage Northrop Aircraft, Inc., an unlikely entrant with no previous carrier aviation experience.¹ Nevertheless the company submitted a heavily detailed design with the in-house designation of N-60.

Northrop envisioned a conventional mid-wing, twin-engine aircraft of all-metal construction with a span of 61 feet and a length of 48 feet, 10 inches.  The outer wing panels would stow for more compact deck storage by rotating the leading edges up and folding the panels aft.

The N-60 also featured a bulbous forward cabin for the four-man crew and a fixed, aft belly radome containing the AN/APS-33A radar.  A single Mk. 41-1 light-weight torpedo was to be carried in the weapons bay, along with rack-mounted sonobouys.  Additionally six 5” rockets could be fitted, three under each wing.

Multiple access panels, doors and hinged sections for easier maintenance were an integral part of the proposal.  Aircraft sub-assemblies were also designed for simplicity in construction and repair.  The engine nacelles were to be fully interchangeable as part of that goal. 

Propulsion was to be provided by two 900hp Wright R-1300-C7B6 Cyclone 7 radial engines, each driving a 12-foot diameter two-bladed Aeroproducts prop.  Designed for catapult launch at 73 knots airspeed, the N-60 could also accommodate two Aerojet 3500lb thrust JATO (Jet-fuel Assisted Take-Off) units for short, 300 foot deck operations.

The choice of the R-1300s was intriguing, especially considering most of the other contenders gravitated to more powerful Wright R-1820 or Pratt & Whitney R-2800 engines.  One result was Northrop needed to build as light an airframe as possible in compensation, for instance using magnesium skins instead of heavier aluminum alloys over the outer wing panel box structures.

Despite the detailed submission, the N-60 did not make the down-select to the final three contenders.  Certainly the engine choice must have played a role in the selection, as well as the company’s lack of carrier aviation experience.  Moreover the airframe design seemed tailored to a less robust structure than one required by the Navy for its operations.

In the end, experience did matter.  Heritage Grumman eventually won the competition with a robust submission slightly shorter in length and a few feet wider in span than the proposed N-60.  However, it was powered by two R-1820s driving three-bladed props each, with enough power to meet all requirements with greater speed, payload and range than the Northrop entry.

December 2012 will mark the 60^th anniversary of the first flight of Grumman’s XS2F-1 Tracker.  This remarkable plane not only became the Navy’s first specifically designed carrier-borne ASW platform, but a piston-engine survivor in the burgeoning jet age, serving for over twenty years in operational squadrons at sea.

The N-60 in turn would fade into oblivion, one of several unproductive Northrop navy proposals submitted during the 1950s.  It was not until the introduction of the F/A-18 Hornet over 30 years later that Northrop would see one of its designs, albeit one heavily modified by experienced McDonnell Douglas, become a successful carrier-borne aircraft.

Footnotes

1:  Jack Northrop developed the Navy’s BT-1 carrier-based dive bomber, the precursor to the Douglas SBD Dauntless, in the mid-1930s while heading the El Segundo, CA-based Northrop Corp., a subsidiary of Douglas Aircraft Company.  Douglas dissolved Northrop Corp. and made it their Northrop Division in 1937.  When Jack Northrop left the company in 1938 it was renamed Douglas’s El Segundo Division.

References and Notes

An excellent brief overview of the OS-117 competition featuring several of the contenders is found in: American Secret Projects – Bombers, Attack and Anti-Submarine Aircraft 1945 to 1974, by Tony Buttler, Ian Allan Publishing, 2010, pp 168-173

Additional OS-117 information from the Grumman perspective is in Grumman Aircraft since 1929, by Rene J. Francillon, Putnam Aeronautical Books, 1989, U.S. publisher Naval Institute Press, pp 350-352.

A great on-line discussion on OS-117, with images of some of the competing types not shown in Buttler’s book, is found here: http://www.secretprojects.co.uk/forum/index.php/topic,584.0.html

Tony Chong is a historian, photographer and a contributing editor to airspace. He leads activities in the Aerospace Systems Display Model Shop and works in El Segundo.

Photo/Image Captions 

  

1) 100_0009w: The cover art for the Northrop N-60 brochure shows the aircraft banking over a late Essex class-type carrier with spurious markings on the forward deck.  Note the size of the N-60 launching from the portside catapult.  The “23” on the cover indicates this is the 23^rd brochure put out by the company.  Photo credit: Tony Chon

                                                              

2)  Img989w: A scan of a 3-view drawing of the N-60 with a human figure for scale.  The “NS-60” notation on the upper right-hand corner of the sheet stands for “Northrop Specification 60.”  Most Northrop N-numbered projects also came with specifications details.  Early in the company’s history the N and NS numbers would usually match.  But as the system progressed into the 1950s the numbers began to diverge widely and rapidly.  Credit: Tony Chong collection 

  

3)  100_0016w: This photo of the general arrangement 3-view from the brochure adds a few more details.  While Northrop had a fixed belly radome, Grumman’s design featured a retractable “dustbin” housing that could be stowed during launch, transit and recovery, lessening drag during non-mission portions of the flight.  Note also the dihedral on the wings outboard of the engine nacelles.  Photo credit: Tony Chong

 

4)  100_0003 (2)w: A detailed fold out drawing of the landing gear and tail hook was included the brochure as well.  Note the rather spindly nature of the nose gear and the unusual retraction process where the gear folds rearward and the wheels go forward.  Photo credit: Tony Chong 

     

5)  100_0003w: This illustration of the N-60 on the elevator of a carrier shows the wings folded in the stowed position with the leading edges up and the upper surfaces of the wings facing inboard.  The picture also shows Grumman F6F Hellcat fighters on the same deck.  Hellcats were withdrawn from active duty carrier-based squadrons in 1948, which makes their inclusion in this 1950 scene a puzzling anachronism.  Photo credit: Tony Chong

   

6)  100_0007w: The complex wing-folding mechanism is illustrated in this drawing, which also shows the forward locking pins, eyelets and actuators.  Photo credit: Tony Chong

 

7)  100_0008_2w:  With space on Navy carriers at a premium, deck-spotting charts like this one from the N-60 brochure highlight the advantages of folding wings for aircraft storage.  Photo credit: Tony Chong

    

8)  100_0004w: This illustration from the brochure shows the N-60 on the deck of CVB-42 USS Franklin D. Roosevelt.  It is eerily similar to a photo of a North American Aviation AJ-1 Savage on the deck of CVB-43 USS Coral Sea that was shot just after the brochure was published in April 1950.  Photo credit: Tony Chong 

     

9)  100_0009aw: Accessibility and ease of maintenance on the N-60 were prominent selling points touted by Northrop.  This drawing shows how those features would operate for engine repair or change-out.  Photo credit: Tony Chong

 

10)100_0018w: A production breakdown drawing was also included in the brochure, where Northrop said it designed the principle airframe joints to require a “minimum of manufacturing and tooling hours.”  Photo credit: Tony Chong

   

11)100_0006w: This cut-away illustration shows crew stations and major equipment and parts placement within the N-60.  Note the torpedo just aft of the crew compartment and forward of the radar equipment.  The crew included the pilot, “assistant pilot,” a forward-facing “radar operator” and a rearward-facing “countermeasures operator.”  Photo credit: Tony Chong

   

12)100_0008w: Pilot forward visibility and the AN/APS-33A radar range limits are illustrated in this drawing.  Photo credit: Tony Chong

   

13)100_0002w: This nicely done illustration shows an N-60 in flight over a coastline area.  While visually interesting it would not be the normal area of operation for the airplane.  Photo credit: Tony Chong