Saturday, April 13, 2013

The Mysterious Ryan Model 147S-2


This article was a particular challenge for me. It also had a very long gestation. I first saw a model of the S-2 back in 2001 and it intrigued me greatly. Once I decided to write about it in late 2010, It took me another two years to unearth enough material to even begin to understand what it was I found.  And then it really got interesting.

Fortunately, I had a lot of help. The information and data provided by Doug Fronius, Norm Sakamoto and John Dale proved invaluable, as did the photo archives uncovered at the San Diego Air and Space Museum (SDASM) by Craig Kaston and myself. The two books by William Wagner (noted in the article) gave added details and backdrop to the program, which were also very helpful. In the end, it proved to be a very illuminating and satisfying experience.

It would prove to be a bittersweet one as well. Shortly after this was posted in Airspace, my editor informed me that the magazine was cancelled. Apparently the leadership team felt it had outlived its value to the department.  

Oh, was a nice gig while it lasted.

But this won't be the last article you see. I have several that have been cleared that I have yet to post on this blog. I will do so in the coming months. I also plan to write new articles down the road for this and other venues if possible. The ultimate goal is to generate enough material to write a new book on the history of Northrop and Northrop Grumman. An ambitions goal, I know, but one that I think is both worthwhile and attainable - at least I hope so. We'll see. 

This article was originally published in the Northrop Grumman Engineering Department's in-house, on-line magazine Airspace, Vol. 3, number 24, November/December 2012. It is reposted here with permission and has approved for public release case number 12-2367.   

 The Mysterious Ryan Model 147S-2

By Tony Chong

The 1960s and early 1970s were not only a turbulent period in American history, but they were also a tumultuous time for the heritage Ryan Aeronautical Company. Great changes occurred in the company’s fortunes during that decade and a half, yet Ryan remained highly innovative and on the leading edge of remotely piloted vehicle (RPV) technology throughout that span. Even more impressive was its forays into the growing field of Low-Observables, or stealth, as seen by its elusive and mysterious Model 147S-2 concept.

The model 147 line began with the 1962 pairing of Ryan with the U.S. Air Force’s 645th Aeronautical Systems Group, a rapid procurement/rapid deployment unit known as “Big Safari.” Tasked with developing special reconnaissance platforms since 1952, Big Safari found an extremely willing and resourceful collaborator in Ryan.1 

Using the existing Model 124 Firebee target as a starting point, the team designed, custom-built and fielded around thirty variants and sub-variants of drones known collectively as Model 147 Fireflies and Lightning Bugs. Nearly 3,500 combat sorties were flown by these vehicles during the Vietnam War by the 100th Strategic Reconnaissance Wing (SRW). 2

But success created its own consequences. The company, which was living from one contract to another during the early days of its Big Safari collaboration, saw its fortunes rise by the late 1960s. Unmanned vehicles of all types, from targets to “Special Purpose Aircraft,” grew from 20% of the company’s total revenue in 1962 to over 90% in each year from 1967 to 1971.3

Flush with success, Ryan sought to expand its lead in RPVs through acquisition, but became a target for acquisition itself.4 In 1968 Teledyne, Inc. bought out founder T. Claude Ryan’s holdings and on January 2, 1969, a new subsidiary of Teledyne called Teledyne Ryan Aeronautical (TRA) was born.5

Its Air Force relationships changed, too. By late 1965 it became clear that Ryan had moved beyond merely modifying existing vehicles into the production of new aircraft. At that point Air Force Systems Command reasserted its authority over such activities. By 1969 the bulk of TRA’s work had transitioned from the free-wheeling, can-do realm of Big Safari and Air Force Logistics Command to the normal, more bureaucratic and competition-driven procurement channels within Systems Command.6

Despite the internal and external shake-ups, the moves created new opportunities beyond the original reconnaissance efforts. More importantly it saw the development of low-observable technology as a new field to investigate. The 1966 contract for the Ryan Model 154 Compass Arrow was one of the company’s initial stealth forays (see 2 April 2013 entry)7.

A multi-mission RPV study in 1971 written by TRA and RCA featured a trio of advanced drone concepts; one for interdiction/strike, one for air-superiority and one for advanced reconnaissance. Of the three versions the Model 147S-2 reconnaissance drone was the one design that delved further into LO.8

The S-2 was to be a day-or-night low-altitude penetrator that was smaller, faster, longer legged and with a lower Radar Cross Section (RCS) than its S-series predecessors.9 Several variations on the basic design were considered, but the two primary concepts that emerged featured a semi-tailless vehicle with cranked arrow delta wings. Canted vertical stabilizers midway out on the span protruded from the upper and lower surfaces of the wings.

The blended compound curvature over the fuselage and wings accomplished more than just lower RCS. It also allowed for greater fuel storage within the shorter length of the drone. In any event, it made for a very streamlined and futuristic-looking vehicle that was just over 21 feet long with a 12.5 foot span for the Configuration 4 S-2 version.10

Propulsion was to be provided by a single Teledyne CAE (Continental) J69-T-406 turbojet with 1,920 lbs. thrust, the same engine as used on Ryan’s supersonic BQM-34E/Model 166 Firebee II. While the engine was capable of supersonic performance, the S-2 was only envisioned to go Mach 0.95 maximum. This was to be done at 2,500 feet above ground level (AGL) during its high-speed “scoring” pass (photo pass) over the target. Ingress or penetration speed was to be Mach 0.65 at 1,000 feet AGL. The vehicle was to pop up to over 40,000 feet for egress at 420 knots cruising speed for maximum range.11

Range was a factor of speed and duration at penetration and scoring altitudes. The more time spent down low would reduce range, but in either case, high or low, it was about double that of the original S-series.

The S-2 nose could be configured to carry different scorer (camera) systems individually or multiple scorer systems at the same time. These could be photo, such as the F-695 or CA-120 cameras or the KA-60 panoramic camera, various laser line-scanner cameras or infrared types like the RS-330R. In addition the vehicle could be optimized for various types of intelligence gathering including electronic or signals (ELINT/SIGINT) data. Electronic counter-measures (ECM) could be carried on-board as well. A real-time data link could be provided on some packages.12

As with the rest of the Model 147 series, the S-2 was to be primarily air-launched from an aircraft, but a zero-ground launch capability with rocket-assist take-off boosters was to be available, too. Retrieval on one version was to be via parachute and the standard Mid-Air Retrieval System (MARS), which was perfected on earlier Model 147 types. However, Configuration 4 appeared to feature retractable landing skids as the parachute housing was removed on that variant.13

The S-2 evoked enough customer interest that Ryan began extensive wind-tunnel testing of its various configurations. Artist’s illustrations showed the vehicle in formation with other operational products as if it had become operational itself.14 The company even produced several display models for presentation.

Unfortunately no prototype or production contract ever materialized. The concept became nothing more than a mysterious design tantalizing the viewer in a painting or a model cabinet already full of other intriguing vehicles.

The end of the American involvement in the Vietnam War was probably the big reason the S-2 did not progress much farther than it did. With no immediate tactical need at hand the Air Force’s attention soon shifted to other areas. The highly classified nature of the reconnaissance RPVs contributed to the lack of awareness by the mainstream military and political leadership, thus stifling any support such a program could have garnered had it been more widely known.15

In 1976 all strategic and tactical drone assets were consolidated under one operational entity: Tactical Air Command.16 Unfortunately TAC was wracked with factious in-fighting over its post-Vietnam role and mission requirements, a fight exacerbated by post-Watergate distrust and the growing stagflation and economic hard times of the late 1970s.17 By 1981 no operational RPVs existed in the Air Force or Navy inventory other than target drones.18

All these reasons and more served to close the door on a very promising future for the S-2 and other unmanned vehicles of the period. Ryan would once again enter a difficult period of small contracts as it struggled to survive through very lean times. It would be another fifteen years before that door would reopen on an unmanned vehicle renaissance.

As for Low Observables, Ryan would continue to explore that technology, developing some extremely interesting designs in the mid-to-late 1970s. But that is a story for another day.

Doug Fronius, Col. John Dale, USAF (ret), Norm Sakamoto and Craig Kaston contributed to this article. Thanks also to the San Diego Air and Space Museum (SDASM) for access to and use of its Ryan photo collection and data archives.

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. 


1. Details of this collaboration can be found in: William Wagner, Lightning Bugs and other Reconnaissance Drones (Armed Forces Journal International / Aero Publishers, Inc. 1982)
2. Ibid, 213, and in: William Wagner and William P. Sloan, Fireflies and other UAVs (Aerofax, Inc. 1992), 13. Both references show the same chart. Note that Tactical Air Command flew some missions with 147NA/NC variants, but the number of flights is unknown and thus not listed in the tally 
3. Teledyne Ryan Drone Sales, 1960-1971 – document in the SDASM collection
4. In 1965 Ryan acquired a controlling interest in Continental Motors Corporation, of which their Continental Aviation and Engineering Corporation subsidiary produced the jet engines used in many of the Model 147 vehicles 
5. Lightning Bugs, 151 
6. Ibid, 146 
7. Fireflies, 35-37. This includes a fascinating account of the competition between Ryan and North American Aviation that led to the Compass Arrow (with heritage Northrop trying to get into the program as well) 
8. Multi-Mission RPV Study – Executive Summary, Teledyne Ryan Aeronautical and RCA, 1971, document in SDASM collection 
9. Lightning Bugs, 212-213. A complete breakdown of S-series sub-variants is listed along with a painting of all the Model 147s and other drones. As noted previously, Fireflies, 12-13 has the same painting and chart. Another good reference is this site that also lists production amounts, as far as they are known: 
10. Model 147 S-2/147 S Comparison, Teledyne Ryan Aeronautical, date unknown, unnumbered page in brochure Xerox copy, Tony Chong collection via John Dale. The actual dimensions are not listed, but scaling out the comparative three-view drawings gave the approximate sizes for each vehicle 
11. Ibid, no page number listed 
12. Ibid, no page number listed 
13. Multi-Mission RPV Study, 6 
14. Lightning Bugs, 206, fireflies, 11, same image 
15. A clear sense of the frustrations in dealing with this wall of secrecy is found in Lightning Bugs, 207-209 
16. Fireflies, 104 
17. A detailed, albeit biased view of this contentious period in Air Force history is found in Boyd – The Fighter Pilot Who Changed the Art of War, Robert Coram (Little, Brown and Company, 2002) 
18. Lightning Bugs, unnumbered third page of Foreword 


The standard references for Ryan RPVs are: Lightning Bugs and Other Reconnaissance Drones, William Wagner, 1982, Armed Forces Journal International / Aero Publishers, Inc., Fallbrook, CA; and Fireflies and other UAVs (Unmanned Aerial Vehicles), William Wagner and William P. Sloan, 1992, Aerofax, Inc., Arlington, TX.

This is an outstanding website dedicated to the AQM-34 Ryan RPVs:

These two documents were critical in understanding the 147S-2: Multi-Mission RPV Study – Executive Summary, Teledyne Ryan Aeronautical and RCA, 1971, San Diego, CA; and Model 147 S-2/147 S Comparison, Teledyne Ryan Aeronautical, no date listed.  

Photo Captions

1. The cover of the July 1971 TRA/RCA RPV executive study was illustrated by three very intriguing designs. The S-2 is the upper-most vehicle. Photo credit: Craig Kaston via SDASM collection. 

2. The full-color original art is even more striking. This piece is unusual in that two artists signed the painting: Robert Watts and Matt Giacalone. Watts would produce some extremely vibrant art for Ryan. Note the configuration of the tail and exhaust on the S-2. Photo credit: SDASM collection.

3. The Executive Summary included three sets of 3-view drawings of their advanced concepts. While Ryan did test a strike RPV variant based on the Model 147S (Model 234), this strike version, like the rest of the proposals shown here, was more refined for the chosen role. The S-2 in this view has a different tail/exhaust design. It is minus the parachute housing seen on the previous two pieces of art. Photo credit: Craig Kaston via SDASM collection. 
4. The baseline Lightning Bug is a Model 147S. The S-2 is shown in comparison and reveals how much smaller in length, height and span the new vehicle was to be. This is the long exhaust version, or Configuration 4 as noted in the previous image. Photo credit: Tony Chong collection via John Dale.

5. This isometric cut-away view shows the parachute housing variant of the S-2. Notice how much slimmer the nose is, too. It is not known at this time if there were to be two versions of the S-2 (an A and B) or if this was just an interim design phase. It is possible the parachute version was for the Navy and the long-exhaust variant was for the Air Force and featured retractable landing skids. Photo credit: Tony Chong collection via John Dale. 


6. Robert Watts painted this image of a parachute-equipped S-2 streaking over agricultural terrain. The structures to the left of the river appear to be American-style farm houses. Nevertheless it is a very dynamic image. The vehicle appears to be climbing to scorer altitude and preparing for a photo run. Photo credit: SDASM collection.


7. This unsigned piece of art, possibly by Matt Giacalone, shows what looks like an earlier variant of the S-2. There is a break in the line between the leading edge of the wing and nose and the verticals appear more outboard than in the other images. Still, it is a nicely rendered artist’s concept. Photo credit: SDASM collection.

8. Two parachute-equipped S-2s are carried by this Navy/Grumman A-6 Intruder in another great image by Robert Watts. As mentioned before it is possible that this version of the S-2 was for the Navy as the practicality of overwater MARS retrieval by helicopter would seem like a much more realistic solution than a skid landing on an aircraft carrier. Photo credit: SDASM collection.


9. This Robert Watts image shows a low-level launch of the S-2 by an A-6 Intruder. The S-2 was designed to fly near nap-of-the-Earth routes at 1,000 feet AGL during ingress.  Watts seems to show it even lower than that. Again, note the drone has the parachute housing. Photo credit: SDASM collection.

10. Aside from the A-6, these vehicles were also tabbed as launch aircraft. The rather poorly reproduced ground launch cart is shown with a barely discernible S-2 on the cradle. The C-135 is an intriguing choice for a launch aircraft. Photo credit: Tony Chong collection via John Dale. 

 11. Wind tunnel testing was done on the Configuration 4 variant, the one without the parachute housing. This view gives a good indication of the increased internal volume in the area between the body and the wing root. The extra volume would allow the S-2 to carry more fuel and have greater range than the baseline 147S. Photo credit: SDASM collection.

12. Another shot of the wind tunnel model shows how compact the S-2 would have been. Photo credit: SDASM collection.


13. A shot from down the tunnel looking back at the model shows the belly of the S-2. The people around the model give a good indication of its size. Photo credit: SDASM collection.

14. While not 100% certain, this gray model of the Configuration 4 S-2 is quite possibly the same wind tunnel model as seen in the previous views, but repainted. The exhaust has been detailed out a bit more as well. Photo credit: SDASM collection.


15. This shot of the Configuration 4 S-2 on a cradle stand on top of a blue-covered table is clearly taken outside. While that seems odd what may be happening is the art department needed photo references of the new vehicle in interesting and dynamic poses to aid them in creating graphics and concept paintings for the company. Photo credit: SDASM collection.

16. Another more practical aspect of shooting models outdoors is the artist can see how the sunlight falls on the vehicle. Notice the differentiation of the reflectivity of light on the starboard canted vertical compared to the reverse-angle canted port vertical. Note also how the shadows fall around the body of the vehicle. This view also shows the exhaust in good detail. Photo credit: SDASM collection.


17. At least a handful of S-2 models were made at the time, of which this is one. A splash-mold was taken off this example by the Northrop Grumman Display Model Shop in El Segundo so new copies could be made if needed. The model comes out to about 1/30th scale. Photo credit: Tony Chong.


18. The stand stated the model to be a 147 SK2, which created a great deal of confusion. There was a 147SK, which was an S-series vehicle modified for launching from Navy ships. It was assumed SK2 was a subsequent Naval 147 type. So far no other reference has been found to substantiate that SK2 was a real variant designation. Photo credit: Tony Chong. 

19. The parachute-equipped S-2 also made it into one of Robert Watts’ periodic paintings of the Ryan family of drones (bottom vehicle on the left side). This also caused confusion as all the drones pictured here were built and flown, so the natural assumption was that the S-2 had been built and flown, too. It was disappointing to discover that this was not true. Photo credit: SDASM collection. 

20. An enlarged view of the S-2 from the previous image shows the parachute housing extending aft and the exhaust plume glowing beneath the fairing. Photo credit: SDASM collection. 

 21. The S-2 made another deceptive appearance on a board of built and flown Ryan vehicles during this photo-op with returning Vietnam POW CMDR Ed Martin (center), ADM Ulysses S. Grant Sharp, USN, ret. (left) and TRA chief executive Robert C. Jackson (right). The S-2 is in the center of the board. Photo credit: SDASM collection.

22. A close-up of the center shows the Configuration 4 S-2 displayed as a half-model mounted on a board with the other half-models of Ryan products. It is worth wondering if this unique presentation still exists. Photo credit: SDASM collection. 

Approved for Public Release: Northrop Grumman Case 12-2367, 12/21/12


  1. This is some good stuff. Thanks for posting it!

  2. Excellent!: Well-written, well-illustrated summary of the history of a little-known (and unknown to me) aircraft project. I look forward to future posts with great anticipation.