Associated reading On Mark - By Richard E. Fulwiler The Monarch 26 - By Robert Lindley Access and Air stairs A question of two aircraft with one identity. When, why, how, who ? An investigation by Richard E Fulwiler Wheels and Brakes

	On Mark Engineering Co. (OM), Van Nuys, California   Specializing and licensed by Douglas Aircraft in A-26 Invader conversions and manufacture and sale of parts. Writen by Richard E Fulwiler In the early 1950s, Grand Central Air Terminal, Glendale, California, was a hot-bed of ex-military aircraft conversion and modification. This historic airport (which exists almost completely intact but is in threat of demolition by the Disney Corporation which now owns the property) was America's first west coast transcontinental terminal and over the years (it closed in 1959) had seen numerous historic aviation firsts. Grand Central Aircraft Company executives came up with the idea to modify an Invader to carry passengers. Several Invaders were completed when the employees split off and established On Mark Engineering at nearby Van Nuys Airport. The company obtained a Supplemental Type Certificate (STC) and began to produce a number of conversions. With conversion production getting underway in the late 1950s, the company created first the Executive, becoming the Marketeer in 1957, which were the unpressurized variants. Most had the rear spar carry-through (which limited cabin access) replaced by a strong and efficient circumferential "ring" spar of On Mark's patented design. By removing most of the original interior bulkheads and adding the ring spar, provided additional room for passengers in the new cabin space of the aircraft. The forward wing spar was not changed because of the magnitude of the re-engineering that would have been required, and would have altered the aircraft's design geometry and excellent flying qualities. With the wings mounted as with the original design, meant that crew members were left with the inconvenience of mounting the flight deck through a crawlway along the right side of the cabin beneath the forward spar. The customer would supply or either purchase a standard Invader which would be restructured in On Mark's spacious hangar. The cockpit would be removed and rebuilt to include dual controls, upgraded instruments and radios, a lengthened fiberglass nose for baggage and radar added, and, more importantly, the cabin was built to customer specifications, and added a number of large windows. The standard A-26 curved windshield design would be retained, with the upper canopy clamshells either painted or skinned over. Air stair doors were installed into the belly, or right side of the fuselage. Also offered, were distinctive 165 gallon wing tip fuel tanks added to increase range, and upgraded P&W R-2800's. Next came, perhaps the best-known of the civilian Invader conversions, the On Mark Marksman series in 1961. The Marksman was the pressurized variant and required a special Supplemental Type Certificate (STC). The airframes were restructured with a greatly altered fuselage, DC-6 / -7 canopy structure with heated windshields, radio/navigation/radar improvements, ring spar, lavatory and food service consoles, soundproofing, air conditioning, increased area vertical tail, long nose, wingtip fuel tanks, improved anti-skid brakes, deicing, and numerous other upgrades and systems included as standard. The pressurized Marksman series were offered in three versions; Marksman A, B, and C. The Marksman A had 2100 hp R-2800-83AM3 engines; the Marksman B had 2100 hp R-2800-83AM4A engines; whereas the premier Marksman C had a raised cabin top that provided a 6 foot walk-through full length cabin, 2500 hp R-2800-CB-16 / -17s and added internal wing auxiliary fuel tanks. Only 15 percent of the original fuselage remained, and dependant on customer options, were designed to carry from 6 to 8 passengers. The base price of the Marksman A was $257,430, up to $361,492 for the Marksman C. The On Mark Marksman was regarded as the best of the A-26 Invader conversions, providing up to eight business executives and a crew of two, an all-weather aircraft that was able to cruise up to 25,000 feet at 325 - 365 miles per hour with a range of  between 1200 and 2500 miles with normal reserves. At 20,000 feet, the pressurized, air-conditioned cabin was at a comfortable 7,500 feet. On Mark also built a model and partial mock-up of the Model 450 which was a greatly modified pressurized aircraft fitted with Allison 501 D turboprops but, after a lot of deliberation, the project was shut down. Oddly, there is no exact record of the number of converted Invaders built by On Mark but its thought to be up to 50 aircraft. Also, the reign of the On Mark aircraft was short - a new generation of business jets led by the Lockheed JetStar and Lear Jet quickly dominated the market and the On Marks were purchased in the late 1960s and 1970s by drug runners who respected the type's long range and load carrying abilities. The following is a quick look at On Mark Invader conversions. On Mark Marketeer - unpressurized. On Mark Marksman A - pressurized. On Mark Marksman B - pressurized. On Mark Marksman C - pressurized.     On Mark Marketeer - Serial No's Prototype serial number: 44-35326, N2889D, N40Y, N401Y Serial number: 41-39161, N1470V, N317V, N317W, N26RP Serial number: 41-39215, N5292V, N4000M, N200M, N142ER Serial number: 41-39497, N71Y Serial number: 41-39516, N237Y Serial number: 43-22258, N1469V, (N36B?),   N94445 Serial number: 43-22444, N4050A Serial number: 43-22602, N9990Z Serial number: 44-34390, N6836D Serial number: 44-34423, N9594Z, C-GHLI Serial number: 44-34524, N558, HK-999E. Serial number: 44-34550, N7769C, CF-CCR, N355Q, HK-1247W, HK-1247P Serial number: 44-34616, N2890D, N300V Serial number: 44-34713, M5538V, N706ME, N36BB, N26MR, N26WB Serial number: 44-34738, N9861C, N600D, N808D Serial number: 44-34754, N66662, N666 Serial number: 44-34755, N67839, N256H, N3035S Serial number: 44-34769, N67162, N500M, N29711, N500MR Serial number: 44-35201, N8025E, N137WG, N437W Serial number: 44-35326, N2889D, N40Y, N401Y Serial number: 44-39495 Serial number: 44-35562, N707TG, N7079S, N9176Z, N7079G Serial number: 44-35681, N60Y, N160Y, N168Y, CF-VPR Serial number: 44-35698, N5001X, N800V, N58071, N67623 Serial number: 44-35708, N5530V, C-GXGY Serial number: 44-35710, N7705C, OO-INV Serial number: 44-35913, N3522C, N303WC Serial number: 44-35938, N4203A, N510X, N516X, D-BACA Serial number: 41-39467, N6844D Serial number: 44-34765, N67160, D-CAFY Serial number: 44-34766, N67807, N1243, N910G, N9150, N26BK  Serial number: 44-35617, N7660C, N600WB Serial number: 44-34774, N67163, N163Y, N917Y     On Mark Marksman - Serial No's ( See clarification below by Richard E. Fulwiler ) Prototype #1 (A) Serial Number: 43-22416, N1394N, N100Y, N140Y, N40XY, N190Y   Serial number: 41-39221, N9636C, N3035S, N256H, N26GT Serial number: 43-22416, N1394N, N100Y, N140Y, N40XY, N190Y Serial number: 44-34415, N60042, N5002X, N900V, N46358, N46598 " Blue Goose " Serial number: 44-34526, N9178Z, N827W, N551EH, N400V, N7977, N26AB Serial number: 44-34567, N9412Z, ZS-CVD Prototype # 3 (C) Serial number: 44-34761, N67158, N400E, N60XY, N60XX Serial number: 44-35698, N5001X, N800V, N58071, N67623 Serial number: 44-35870, N1471V, N320, N99426               Additional details   Note 1. Bulkhead modifications Note 2. Rudder modifications Note 3. Conventional lateral wing spar versus ring spar   Note 1. Bulkhead modifications by Richard E Fulwiler: (See photos below) Looking into how the Invader airframe developed as various companies undertook modifications to increase space and performance, I Checked several links and found data on the B.A.M.R.S. A-26 restoration, information which can be found via this link :   http://www.caea.info/en/coll/b26.html    I have accessed their photo files many times because, during the restoration process, many photos were taken documenting the disassembly and exposure of internal components and structure. To me this is important because it shows why certain skin seam lines overlap where they do because the underlying structure provides a point of attachment, and what that structure looks like.   As an example, compare the aft bulkhead ( above two photos ) where the empennage attaches on the standard fuselage B.A.M.R.S. A-26 photo to Graham's N99426  ( post Andrew ) Marksman photo. It shows how much the standard fuselage was modified by On Mark to raise the cabin top and provide for pressurization by the solid aft pressure bulkhead. It is fortunate for us that both photos were taken from close to exactly the same vantage point.           Note 2. Rudder modifications on On Mark Invaders The actual difference in rudder design between the A-26B/C models and the On Mark Invaders is in the chord of the rudder - it was widened about a foot, in an attempt to lower the VMC ( the minimum single engine control speed ) with one engine operating at take-off power and the second engine windmilling - rather critical on any twin engine aircraft on take off, which on the early model A/B 26s was 140 kts). Air Spray looked into the possibility of adapting the K model rudder to their B/C aircraft. For the most part, it was a straight forward swap. Simply remove the original B/C rudder, swap positions on the rudder attachment brackets ( Top bracket moved to the lower position and bottom moved to the top position ) and bolt on the K rudder. However, the FAA insisted that Air Spray also had to install the two rows of vortex generators that had been installed vertically on the right side of the vertical stab in front of the rudder. Unfortunately the vortex generators were not available and they would have had to have them manufactured to match the original drawings, so it didn't go forward with the modification.   The two shots above show the obvious difference in rudder size, the top detail showing an A-26C and the lower shot an On Mark B-26K         Note 3. Wing spar modifications The On-Mark Marksman had three major modifications from the stock A/B-26 B/C 1. A "ring" spar installed in bomb bay, replaced the original spar carry thru structure ( which was stronger than original and allowed more bombs to be carried ) 2. A wing spar reinforcing kit which placed a 1/4" plate on the top and bottom of both spars, running from just inboard of each nacelle, running through the nacelle to about 3' outboard of the nacelle The modification wasn't that noticeable and didn't cure the problem - it was eventually discovered they were actually breaking just outboard of the fuselage, usually on the left side rear spar).   Note: On an similar note but not directly associated with On Mark and as we're talking Wing spar mods A short term modification and used on both Douglas and On Mark Invaders, came in the form of a steel reinforcement cable which looped around a cleat fitted to a Titanium stress plate modification on the inboard section of the wing ( as seen below ) and was fixed within the fuselage, inboard of the main spar. Although a little rough around the edges, this short term solution allowed Invaders that had suffered spar failure to undertake ferry flights in order to have the broken spar repaired or replaced. Flight parameters were severly limited, but the mod was an FAA approved device and helped companies to recover aircraft that would have otherwise been grounded. This interim mod was designed by engineers at Air Spray and believed used on N7079G when she suffered an in-flight spar failure. Above, Air Spray Tanker 32 wing spar reinforcement for ferry flight                    Other differences The most visible modification, was the installation of 300 gallon tip tanks, which effectively doubled on board fuel but aggravated the spar problem because of their extremely long movement arm. If you had a surplus Marksman ( and not a civilianized version ) the only thing you had to do was remove the tip tanks and install a set of the original wing tips to make it look like a B/C. But the most noticeable differences in the K model is the engine (higher horsepower -2500 vs 2000), the prop (still a Hamilton Standard but slightly broader and squared off tips and the rudder - the chord is 1 ft wider and there are a couple of rows of vortex generators running up the right side of the vertical stabilizer just in front of the rudder.

	LeTourneau Based in Long View, Texas, this company did some very early Invader executive conversions. There modifications basically included a six-place cabin in the rear fuselage and an air stair door. Number of conversions is not known. Note: Robert Gilmore LeTourneau (November 30, 1888–June 1, 1969), born in Richford, Vermont, was a prolific inventor in the earthmoving industry. His machines represented nearly 70 percent of the earthmoving equipment and Engineering vehicles used during World War II, and he was responsible for nearly 300 patents. With the help of his wife, Evelyn, he founded what became a private, Christian university, LeTourneau University, in Longview, Texas, and was known as a devoted Christian and generous philanthropist to Christian causes, including to a camp and conference grounds that now carry his name, "LeTourneau Christian Center."He was sometimes called "God's businessman". Based in Long View, Texas, this company did some very early Invader executive conversions. There modifications basically included a six-place cabin in the rear fuselage and an air stair door. Number of conversions is not known, however listed below are a few of the A-26 invaders that were modified. Serial number: 43-22275 Serial number: 44-34134 Serial number: 44-34520

	Rock Island Oil & Refining Co., Kansas conversion Oddly named company had an aviation division that in the 1960s produced the very attractive Monarch-26s. The company purchased several dozen surplus Invaders and moved them to their aviation facility at Hutchinson, Kansas. A number of Rock Island aircraft were built up and they were basically stock looking but had a lengthened nose, passengers cabin with extra windows, and upgrade cockpit and avionics. Monarch 26 - 1960's, longer nose, systems upgrades. The Monarch 26 was a corporate aircraft conversion performed by the Rock Island Oil and Refining Co of Wichita, Kansas. The company purchased six surplus Invaders (ex-French AF aircraft that had served in Indochina) out of the Clark Field storage facility. The original Invader airframe was extensively reconfigured with re-contouring and extensive re-skinning. In order to provide for more interior cabin space, an new wing spar was designed to replace the original straight-through configuration and new upper and lower fuselage structures were extended from the rear spar to the fin root fillet. The new cabin could accommodate up to six passengers in a low-density arrangement, and featured floor heating, a restroom, catering facilities, and panoramic windows. There was an airstair door on the rear starboard side. The extended nose was 30 inches longer than the original. Because of a fear of wing failures, the Rock Island engineers decided not to add wingtip fuel tanks, but added additional fuel cells in the outer wing panels, which raised the total fuel capacity to 1012 US gallons. The cockpit was fitted with dual controls, new instrument and overhead panels, and "metalized" double-paned cockpit canopies. Anticipating more orders, Rock Island acquired 30 more surplus Invader airframes, this time from storage at Davis Monthan AFB. However, the Monarch had only limited success in the corporate aircraft marketplace, with only 4 being completed, including three in-house. In addition, the Monarch found itself in competition with the first generation of corporate jets such as the Sabreliner, Jetstar, and Learjet. The majority of excess airframes that had been acquired were sold to parts brokers in 1969 but several examples went on to serve as aerial tankers in the USA and Canada. Some also ended up as flying warbirds, museum exhibits, and potential restoration projects. Rock Island capitalized on its experience with Invader conversions by creating the Consort 26, which was designed for research and development purposes. All military equipment was removed, the bomb bay was sealed up, and a reinforced floor was added. Three Invader airframes were modified in this way and were sold or leased to aerospace companies as platforms for system development programs. Airframes that were "purchased" by Rock Island Oil & Refining Serial number: 44-35643 Serial number: 44-35371 Serial number: 44-34390 Converted 1960 Serial number: 44-34602 Converted 1987 Serial number: 44-35911 Converted 1960 Serial number: 41-39561 Serial number: 44-34612, Serial number: 41-39467 Serial number: 44-34146 Serial number: 44-34615 Serial number: 44-35893 Serial number: 44-35217 Serial number: 44-34736 Serial number: 44-35682 Converted Serial number: 44-34725 Serial number: 44-35964 Serial number: 43-22374 Serial number: 44-34749 Serial number: 44-34609 Serial number: 44-35505 Serial number: 44-34697 Serial number: 44-34592 Serial number: 44-35994 Serial number: 44-35752

	Rhodes Berry, California conversion Possibly the ugliest of all Invader conversions, the Rhodes Berry Silver 60 was built at Whiteman Airpark in the San Fernando Valley of southern California during the late 1950s. The fuselage was completely redone resulting in a swollen unit that could accommodate up to 16 passengers. Also, because of the deeper fuselage, the nose gear could now retract straight back without first swiveling as on stock Invaders. The first Silver 60 flew on 25 June 1960 with the registration N5510V. Some sources state another example was built but we can't find photos of just the first and its final history is not known. Silver Sixty - 1960, fuselage revised for up to 16 passengers.

	Lockheed Air Service (LAS), California conversion A separate arm of Lockheed Aircraft, LAS operated from Ontario, California, and specialized in the conversion of airframes. In the late 1950s, the company created the Super 26 which utilized just the wings, engines, tail, and landing gear of the Invader. A new fuselage with a pressurized cabin that was 22 feet long and six feet high was built and this could carry six-to-nine passengers. Constellation windows and cockpit sections were utilized and the first example, N5052N, flew in mid-1960. Apparently only one was built and the hulk finally wound up with Air Spray in Canada as a parts source. Super 26 - new fuselage with A-26 wings, tail and engines.   The modifications in detail consisted of: Increased interior height by raising the fuselage top ( looks like a foot above the normal A-26 ) - and - deepening the belly ( by 6 to 9 inches - starting with a fairing at the nose landing gear well / forward bomb bay lower-partial bulkhead ) carrying this height section aft to the break in the parallel longitudinal reference ( tapering to the tail ). Increased the interior cabin length by adding what appears to be a 6 foot " plug " in the fuselage aft of the wing. This configuration is remarkably similar to the L.B. Smith Tempo II conversion design. With the incorporation of the " ring spar " to replace the rear wing spar carry-through structure, the interior would be open from the rear face of the forward wing spar, all the way back to the rear pressure bulkhead ( behind the rear-most cabin side window ).   LAS was said to have used Constellation L-1049 Super G cabin windows in conjunction with pressurization. These can be identified by the square shape with generously rounded corners as seen on the aft fuselage ( 4 on each side, includes the entrance "Airstair" to starboard and the escape panel opposite ) and the pair below the right wing. The oval windows above the wing appear to be horizontally sectioned from the side window size. The cockpit windshield appears to be the normal A-26 curved units but with small cockpit side windows, both incorporating heavier framing to withstand pressurization loads. This configuration can also be found on the L.B. Smith Tempo II conversion.   A newly designed fiber glass nose with considerable length and contour revisions over the standard A-26. The added length of the nose was certainly increased to compensate for the added fuselage length aft of the wing. This would bring the C. G. back to the correct location and aerodynamically improve the shape. An added benefit would be an increased capacity to carry luggage and baggage in the nose along with the aft compartment ( note the small open doors on the right side, nose and tail ). A half-dome transition shape to the aft end of the cabin top to blend with the standard A-26 tail section. Note how the vertical stabilizer leading edge blends into a horizontal dorsal spine, ending at the half-dome transition. These shapes can be found on the On Mark Marksman " C " configuration. As the LAS Super 26 preceded the Marksman series, it seems that there were many design elements used by the various conversion companies, especially those operating from the San Fernando Valley area of California. It must be noted, however, that On Mark Engineering dominated the A-26 Invader conversion business, and was successful beyond measure compared with their competition.

	L.B. Smith, Florida conversions L.B. Smith Aircraft Corp. Miami, Florida Founded in 1947 at Miami Intl. Airport by company president L.B. Smith, it quickly became one of the foremost aircraft conversion, overhaul and modification centers in the United States. They did executive aircraft interiors for many types from the Douglas DC-3 to the Lockheed Jetstar. Their most famous conversions were the ex-military Douglas A-26 Invaders as the Smith Tempo I / II executive transports and the Curtiss C-46 Commando which became the Smith "Super 46". Seven or more C-82 Packets were briefly acquired by L.B. Smith in 1955 where they were de-militarised for civilian service in Latin America. L.B. Smith was closely associated with a similar company called Aerodex Inc., who were a CAA approved aircraft repair station. Based in Miami, Florida, this company specialized in conversions of the C-46 as well as producing airliner interior components. The company decided to completely reengineer the Invader and replaced both spars with ring spars built of aluminum. This also saw the increase of the wing center section which moved the engines on each side 20 inches from the cabin to reduce noise. The aircraft, like the On Marks, received DC-6 wheels and brakes, new canopy and cockpit, lengthened nose, rebuilt fuselage, and numerous other modifications. Named the Biscayne-26, it is thought that only one aircraft was built before the company decided to start with a clean sheet of paper. The new aircraft would have a completely new and much larger fuselage that would also be pressurized. Two variants were to be built, the Tempo I (unpressurized) and the Tempo II (all the bells and whistles). The Tempo II was ten feet longer than a standard Invader and had a 28-foot cabin that could accommodate up to 13 passengers. Every thing else on the first aircraft was completely modernized and it was a beast, making its first flight as N4204A during October 1959. Price was $375,000 but it appears only one was built and it eventually went to the University of Nevada and was lost over the Sierras when it came apart. Smith Biscayne 26 Smith Super 26 Smith Tempo I - unpressurized. Smith Tempo II - pressurized. The first of these conversions was known as the Super 26. It was fitted with wingtip fuel tanks and had executive accommodations, but was otherwise similar to the basic Invader. Later conversions included the Smith Tempo series. The Smith Tempo I was powered by R-2800 B-series engines and had an unpressurized fuselage. The Smith Tempo II had R-2800 C-series engines and was equipped with full cabin pressurization. Both versions featured wingtip tanks and a new 9 foot 7.5 inch extension on the fuselage that could accommodate from ten to 13 passengers. Other A-26 Invaders registered at one time with L.B.Smith Corp * Serial number: 44-35238 - N3477G, 1966-1970 * Serial number: 43-22569 - N3478G, 1964-1970 * Serial number: 41-39509 - N3480G, 1963-1970 Serial number: 43-22652 - N8018E Serial number: 44-34535 - N8020E, June 1959 Serial number: 44-35201 - N8025E, Jan 1962 Serial number: 44-35323 - N8026E,  July 1958 * Serial number: 43-22730 - N8027E, 1964 * Serial number: 44-35541 - N8032E Serial number: 44-35696 - N8036E, June 1963 Serial number: 44-35788 - N8058E, 1962 Notice how the registrations tend to follow suite   Note: * Possible candidates for Smith Tempo II conversion

	Grand Central Air Services The early days of air travel in Los Angeles have essentially nothing to do with those often dreaded letters L-A-X. In fact, the origins of commercial air travel in America began in Glendale in the early portion of the 20th century in what eventually became Grand Central Air Terminal (GCAT). In the early 1950s, Grand Central Air Terminal, Glendale, California, was a hot-bed of ex-military aircraft conversion and modification. This historic airport (which exists almost completely intact but is in threat of demolition by the Disney Corporation which now owns the property) was America's first west coast transcontinental terminal and over the years (it closed in 1959) had seen numerous historic aviation firsts. Grand Central Aircraft Company executives came up with the idea to modify for executive use, the first batch of Ex Military A-26 Invaders to enter the civilian registry, and thus start the ball rolling on what was to be the birth of the VIP transport Invader, in all its many guises. Several Invaders were completed when the employees split off and established On Mark Engineering at nearby Van Nuys Airport.

	Wold Corp. The Wold Invader was powered by two Pratt and Whitney R-2800-CB-16 engines, rated at 2,400 h.p. with water injection, and driving Hamilton Standard reversing propellers. Although of somewhat small cross-section, the fuselage is luxuriously furnished for eight passengers in four large reclining chairs and a divan. The cabin is "super-soundproofed" and provided with a toilet and extensive storage facilities, and optional equipment included the following: Sperry A-12 autopilot; Bendix X-band and weather radar; Collins Integrated Flight System; Bendix D.M.E.; Sperry engine analyzers, and the following radio equipment—sufficient to take the aircraft anywhere in the world—Collins 51R3 Omni receiver, Bendix Omni receiver, 17L3 Collins transmitter, series 440 Wilcox 50W V.H.F. transmitter simplexed with Wilcox receiver, dual Collins R.M.I., dual A.D.F. Bendix MN62, Bendix markerbeacon receiver, F-ll A isolation amplifier, cockpit and cabin speakers, Collins 51V glideslope receiver, and R89 glide-slope receiver. More than 80 multi-engined executive and airline transports, with a total value exceeding £5m, were sold by William C. Wold Associates, an American company specializing in transport aircraft sales. The simple but highly successful Wold technique centred on the production of a small brochure describing the aircraft, which was circulated to a mailing list of 7,000 company executives, pilots, purchasing agents, export and import firms and operators, both in the U.S. and abroad. The companies flag ship conversion identified in the Wold brochure was the 300- m.p.h. Douglas B-26 Invader conversion with a luxurious five seat cabin and toilet.

	Hamilton Aircraft In 1966, wing spar cracks had started to show up in some of the FAB's (Brazilian Air force) Invaders. In an attempt to prolong their service lives, in 1968, several FAB Invaders were flown back to Tucson, Arizona for an upgrading by the Hamilton aircraft Company. Most of the changes involved IRAN (Inspect and Repair as Necessary) of avionics, communications equipment and weapons systems. 15 aircraft were refurbished. In addition, three new aircraft (FAB serials 5173/5175) were acquired by Hamilton from surplus stocks as attrition replacements. Unfortunately, one of the FAB B-26 was so badly corroded that it had to be struck off in Arizona and replaced by another. In addition, a civilian B-26 was impounded by the Brazilian government in June of 1966 due to its involvement in illegal smuggling activities. It sat derelict at Brasilia until 1970, when the FAB finally took it on charge and used it as a transport aircraft under the FAB serial number of 5176. In spite of the Hamilton rebuild program, wing spar cracks began to reappear in the wings of many FAB B-26s in 1972, which led to the decision to retire the B-26 from FAB service rather than to attempt to keep them in the air for much longer. The withdrawal took place in stages, beginning in 1973 and lasting until December of 1975.

	Slick Airways There were certain Ex Military A-26 Invaders that were brand new and never AAF accepted. These Invaders came direct from Douglas to Kingman, to the RFC for disposal. Charles Babb purchased several of these for $2000 each...brand new airplanes with the cushions still wrapped in plastic. One of these Invaders went to Milton Reynolds and was registered with his company then, the Printasign Corp. of America. After his round-the-world 1947 flights with Bill Odom at the controls, it went to Phillips Drilling in 1948. They had a large window installed in the aft fuselage and a cabin door installed. In 1954 it went to Earl Slick of Slick Airways, of Burbank, CA. Aviation Power Supply of Burbank installed the tip tanks in January 1956, and also did some other fuel system work and other modifications. In July 1956 On Mark at Glendale installed a weather radar unit with the radome on the nose. In October 1956, a company in Denver replaced the Bendix brakes with new Goodyear brakes. In August 1957, On Mark did some aft fuselage mods, including lowering the aft floor. In July 1961, On Mark did some more fuel tank work. In March 1967, the airplane went to the Ventura Division of Northrop, and pylons were installed to handle "Horkey Moore launcher" rails to mount RP-78 targets. Not sure about these items but it appears the Invader was used as a launcher of new target drones. Shortly afterwards, or maybe when the wing racks were added, the airplane went to On Mark again to have fatigue straps added to the front wing spars and shear plates added to the rear spars, and the wing structure and attach points were also inspected with the wings and engines off the fuselage.

	On Mark Marksman Conversions - Richard E. Fulwiler.   Registration # (Red) at conversion   Marksman - Conversions Conversion sequence Marksmen production No's 1 - 8 Models A - C Note: SP - Special Purpose   # 6 - Marksman C - Serial Number: 41-39221, N9636C, N3035S, N256H, N26GT          Prototype # 1 A - Marksman A - Serial Number: 43-22416, N1394N, N100Y, N140Y, N40XY, N190Y                  # 7 - Marksman C - SP Serial Number: 44-34415, N60042, N5002X, N900V, N46358, N46598 " Blue Goose "                     # 2 - Marksman B ? - Serial Number: 44-34526, N9178Z, N827W, N551EH, N400V, N7977, N26AB                        # 5 - Marksman C - Serial Number: 44-34567, N9412Z, ZS-CVD          Prototype # 3 - Marksman C - Serial Number: 44-34761, N67158, N400E, N60XY, N60XX                  # 8 - Marksman C - SP - Serial Number: 44-35698, N5001X, N800V, N58071, N67623                         # 4 - Marksman C - Serial Number: 44-35870, N1471V, N320, N99426         Reference Survivors: ( Intact ) Marksman # 2 (as N26AB)    "Intimate Invader" Dona Ana County Airport, Santa Teresa, NM    Marksman # 6 ( as N26GT )   South Mountain High School, Phoenix, AZ      Survivors: ( Disassembled  - Last known locations ) Marksman # 4  ( as N99426 ) Van Nuys Airport, Van Nuys, CA   Marksman # 5  ( as ZS-CVD )  SAAF Museum, Snake Valley AB, South Africa