Douglas A/B-26 Invader

Known On Mark Marksman airframes

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On Mark - Main page

The Marksman build sequence and also the photo sequence is as detailed below.
Clarification by: Richard E. Fulwiler


  Marksman #1 - N100Y ( " A " model )
Serial Number :  43-22416


Marksman B #2 - N827W
Serial Number :  44-34526


Marksman C #3 - N400E
( first of, and all subsequent were " C " models )
Serial Number :  44-34761


Marksman C #4 - N320
Serial Number :  44-35870


Marksman C #5 - ZS-CVD
Serial Number :  44-34567


Marksman C #6 - N3035S
Serial Number :  41-39221

Finally, the Special Purpose Marksman "twins"


Marksman #7 – N900V 
( Operational as N46598  "BLUE GOOSE " )
Serial Number :   44-34415


Marksman #8 -  N800V 
( Operational as N67623 )
Serial Number :   44-35698
( Sister-ship - Identical except for Reg. # )



Serial #: 43-22416
Construction #: 18563
Civil Registration:
  On Mark Marksman
Name: None
Status: Unknown
Last info: 1970


Registered as N1394N
On Mark Engineering Co., Van Nuys, CA,
- Registered as N100Y.
- Used as demonstrator for pressurized Marksman.
Purolator Products Inc, New York, NY, 1961.
Transelco Inc, Rahway, NJ, 1963-1964.
- Registered as N140Y.
Occidental Leasing Corp, Los Angeles, CA, 1966.
- Registered as N190Y.
Occidental Oil of Libya Inc, Los Angeles, CA, 1968-1970.
Occidental Oil, Los Angeles, CA, 1970.
- Registered as N40XY.
- Emergency landing, engine fire, Beirut, Lebanon, Dec. 19, 1970.


Serial #: 44-34526
Construction #: 27805
Civil Registration:

  On Mark Marksman
Name: Intimate Invader
Status: For Sale
Last info: 2002


Registered as N9178Z by ???, 19??.
A.M. Wheaton Glass Corp, 19??.
- Registered as N827W.
E.T.S. Hokin Corp, San Francisco, CA, 1961-1966.
- Registered as N551EH.
- Converted to On Mark Marksman, Van Nuys, circa 1962.
CWC Air Inc, Flushing, MI, 1969.
- Registered as N400V.
Certified Check & Title Corp, Wilkesboro, NY, 1970.
- Registered as N7977.
Twin Cities Aviation, Inc, Edina, MN, 1972.
Dennis M. Sherman, West Palm Beach, FL, 1976-1978.
- Registered as N26AB.
- Flew in quasi USAF scheme, "Intimate Invader".
Oklahoma Aircraft Sales, Yukon, OK, Apr. 1981-1986.
Continental Jet Inc, Clarksville, TN, Mar. 1987.
Charles Bella, El Paso, TX, Chaparral, NM, 1988-2002.
- Open Storage, santa Teresa, NM, 1990-2002.
- Still marked as "Intimate Invader".

Reported for sale, 2002.



Serial #: 44-34761
Construction #: 28040
Civil Registration:
  On Mark Marksman
Name: None
Status: Unknown
Last info: 2002


Delivered to Reconstruction Finance Corp as 44-34761, 19??.
- Immediately put up for dispossal, 1945-1946.
Superior Oil Co, Lafayette, LA, 1954.
- Registered as N67158.
Colorado Interstate Gas, Colorado Springs, CO, 1961-1964.
- Registered as N400E.
Occidental Leasing Corp, Los Angeles, CA, 1966-1969.
- Operated by Occidental Petroleum, Las Angeles, CA, 1966-1970.
- Operated by Holiday Inns Of America, 1968.
Occidental Chemical Corp, Los Angeles, CA, 1970-1972.
- Registered as N60XY.
- Ferried from Beirut to USA, Feb. 13, 1974.
Registered as N60XX, Fort Lauderdale, FL 1976-2002.
- Sale Reported.

Thought to have been lost during smuggling operations.




Serial #: 44-35870
Construction #: 29149
Civil Registration:

On Mark Marketeer
On Mark Marksman C
Name: The Hustler
Status: Stored
Last info: 2002


Converted to On Mark Marketeer and Registered as N1471V
L.B. Maytag Aircraft Corp, Miami, FL, 1962-1964
- Registered as N320.
- Rebuilt as On Mark Marksman C, Van Nuys, 1963.
National Bank, Tulsa, OK, 1966-1969.
Trinity Industries, Inc, 1969
Confederate Air Force, Harlingen, TX, 1970-1972
Struck off US Civil Register, Circa 1975
- Reported sold to South America.
Noted in ferry markings N99426, Opa Locka, FL, July 1981.
F. J. Luytjes, Dalton, PA, 1984
T. K. Edenfield, Albuquerque, NM, May 1985.
C. H. Midkiff, San Antonio, TX, Sep. 1986.
Outlaw Aircraft Sales, Inc, Clarksville, TN, Apr. 1987
Wayne County Sheriff Dept, Detroit, MI, July 1988-1990
Reported sold in Brooksville, FL, 1992-1995.
- Damaged by Hurricane Andrew, Tamiami, FL, Aug. 24, 1992.
- Open Storage, still damaged, Tamiami, FL, 1992-1995.
Patrick M. Murphy, Brisbane, Queensland, Australia, 1998-2000.
- Shipped to Brisbane, 1998.
- Assembled at Caboolture, Queensland, Apr. 1999.
- Planned restoration to airworthy.
Matt Jackson & Howard Keck, Thermal, CA, 2000-2002.
- Shipped from Australia.
- Arrived dismantled, Van Nuys, Dec. 2000.
- Still in container, Van Nuys, 2002.
- Under restoration, the rumour being that she
 is being fully restored to possibly race at Reno with her power plants being Wright R-3350's  



Serial #: 44-34567
Construction #: 27846
Civil Registration:
  On Mark Marksman
Name: None
Status: Stored
Last info: 1992


On Mark Engineering Co, Van Nuys, CA, 19??
- Registered as N9412Z.
South African Iron & Steel Industrial Corp, Wonderboom, South Africa, Feb. 27 1962-1971
- Registered as ZS-CVD.
- Damaged in belly landing, Omaruru, Jan 13, 1971.
- Repaired.
- Withdrawn from use, 1976-1977.
Vern McWilliams, Durban, South Africa, 1977.
- Acquired for engines.
SAAF Museum, Snake Valley AB, South Africa, Aug. 9, 1977-1992.
- Stored in Museum storage Hanger, Feb. 1982.

On Mark Marksman – ZS-CVD 

My intent has been to bring to the forefront the background and history of the executive conversions based on the Douglas Invader. Following is an aircraft's history written as a tribute to one of the eight On Mark Marksman conversions, and is the only Marksman that I have a personal connection with. This writing has been inspired by a group of photographs recently provided by Wayne Allen-Smith, step-son of Carl Reck who was one of the pilots flying her during her service with South African Iron & Steel Industrial Corp ( ISCOR ). The series of photos were taken at the On Mark facility at Van Nuys in late February, 1962. A few days prior, I was privileged to see and board this particular example while she was being prepared for customer delivery

Because On Mark Engineering was 10-miles away from my home, the most successful of these Invader conversion companies was practically at my doorstep. Building a display model for the On Mark sales manager gave me open access into their facility. A school holiday celebrating George Washington’s birthday had me out at the Van Nuys airport, finding ZS-CVD on the north side of the On Mark hangar. I followed a workman out to the aeroplane, watching in awe as the beautifully engineered Airstair opened before me, then was invited aboard to tour the interior. I sat in the jump seat behind the pilot’s chair as the technician made some final adjustments in the cockpit. The memories of that event are still as fresh as if it were yesterday. The photos of ZS-CVD must have been taken within days of my visit as she was gone by the time I was able to return with a fresh roll of film. I was 16 at the time.

The drawings included are mine showing the ZS-CVD's profile as well as the ISCOR logo.

Richard E. Fulwiler                                                                         August, 2015


On Mark Marksman – ZS-CVD 

      ( conversion of A-26B-61-DL Invader, Serial # 44-34567, Construction # 27846 )

Only eight full Marksman conversions were completed by the On Mark Engineering Company based in Van Nuys, California, and ZS-CVD was one of them as a " C " model Marksman.

The On Mark " MARKSMAN " series were all built as pressurized business aircraft, converted from surplus WWII Douglas A-26 Invader attack bombers. With restructured fuselages, they could be identified by the modified cockpit glazing that incorporated Douglas ( " off - the - shelf " ) DC-6 / -7 flat panel windshields, and side windows. This was done because these components were already certified for use on Douglas aircraft, and On Mark was licensed by Douglas to install them on the Marksman using approved installation methods. The cockpit forward side windows opened as on the DC-6 ( inward, and sliding back on tracks ), while the rear cockpit side window was the same unit as the forward one only fixed, inverted and reversed ( unique to the Marksman ). The cabin side windows, including one installed in the Airstair door, and the starboard side foot-well ( two under the wing ) were symmetrically square with rounded corners, again as standard to the DC's that were pressurized.

From the completely new fabricated cockpit over-head structure, the fuselage top tapered down, diminishing in height back to the vertical stabilizer spine on the first two Marksman conversions ( registered as N100Y and N827W completed in 1961).

With the Marksman " C " , the fuselage was further modified to provide for a full height, 6' 1", walk-through interior with a constant cross section from the cockpit overhead back to the aft cabin pressure bulkhead. Marksman N400E was the first " C " model, completed before I began my visits inside On Mark starting early in 1962.

The Marksman “ C “ conversions had R-2800 CB17 engines rated at 2,500 hp with ADI, and Hamilton Standard fully reversible broad chord ( High-activity ) 43E60 propellers with auto-feather. Other identifying features on the Marksman series were the vortex generator tabs lined up the starboard vertical tail, as well as the all-metal rudder extended 6" in chord and the addition of a booster / servo tab installed above the standard trim tab. The other noticeable difference in the Marksman was the cabin supercharger scoop mounted on top of the port engine nacelle, the 165-gallon wing tip tanks, and the aerodynamically refined, elongated “ 103-inch “ nose for 1,000-pounds of baggage and weather radar.

The airframe that became ZS-CVD was originally built for USAAF by Douglas Aircraft Co. as an A-26B-61-DL Invader, Serial #: 44-34567 / Construction #: 27846.  To the civil market, registered N9412Z , she was converted by On Mark as a Marksman C executive aircraft for South African Iron & Steel Industrial Corp ( ISCOR ). Registered as ZS-CVD on completion in February, 1962, she was flown to South Africa, arriving at the Wonderboom Aerodrome ( Pretoria ), 27 February. The ISCOR  pilots flying ZS-CVD were Co. Chairman Col. Bob Preller and Carl Reck, seen flying her in and out of Wonderboom regularly through the Sixties and into the Seventies. Wayne Allen-Smith writes  :

      “ I can remember with fondness Carl Reck ( my step dad ) and Bob Preller coming back from a  business trip and hearing those familiar engines flying over our home in Waterkloof. They would wiggle the wings of the Marksman and head of to Wonderboom airport. I knew dad was home. “

 Another pilot shown to have flown ZS-CVD later on was Stan van Niekerk. Col. Bob Preller was once asked what motivated ISCOR to buy their Marksman; the short answer was that “  it was within a stipulated budget amount whilst giving the speed / range for their missions “.

A reported wheels up landing incident damaged ZS-CVD at the UIS mine ( part of ISCOR for mining tin ) 13 January, 1971.The airplane lay on the runway for months before it was jacked up, new propellers fitted and flown back to Wonderboom. She also caught fire at UIS on start up.

ZS-CVD was seen in Port Elizabeth in 1975 delivering 1974 Miss World Anneline Kriel for some function there.

Withdrawn from use with ISCOR, she was first sold to a Mr. Jordaan, then sold to Mr. Vern McWilliams for engine spares, and offered to SAAF Museum 9 August, 1977. Collected from Wonderboom after the engines were removed, she was dissembled and taken to South African Air Force Museum and remained in open storage compounds at Swartkop for decades, listed as “  Stored ( Derelict )  “.

Representing a small group of aviation history hobbyists, I sent a letter of appeal to Captain Leon Steyn, Research Officer Air Force Museum in January of 2010, notifying the museum of the rarity and importance of the Marksman. Capt. Steyn responded  :  

      “ We acknowledge receipt of your enquiry.
         While the aircraft is of immense value for it’s rarity, the South African Air Force Museum has

chosen to focus its limited resources for restoration and preservation efforts on aircraft that served with the SAAF.      
Unfortunately the On Mark Marksman has been left derelict and deteriorated since it arrived 
at the museum due to other restoration and maintenance priorities.
Its restoration or refurbishment is largely dependent on the intervention and involvement of
private entrepreneurs for funding and technical knowhow to save this historic aircraft. “

Sometime in 2010, the dissembled ZS-CVD was acquired by the two business partners and avid collectors Mr. Witold Walus and Mr. Willie Muntingh, and moved to their operations at Drakensberg Truck Manufacturers, NE of Pretoria (on D327 / Wallmansthal Rd. between R101 and N1 ) where the Douglas DC-6 Empress of Suva  ( ZS-MUL ) is now on display. In the YouTube video showing the arrival of the Empress of Suva on the dirt strip adjacent to the Drakensberg facility ( 4 December, 2010 ), the fuselage of the Marksman ZS-CVD can be seen inside the boundary fence line. Satellite map imagery verified her location. A satellite view in 2012 shows the remains moved to the north end of the property. As of this writing in 2015, no restoration work appears to have been accomplished.


On Mark Marksman enthusiast,

Richard E. Fulwiler







Above, N256H at Miami International in June 78


Serial #: 41-39221
Construction #:
Civil Registration:
Name: None
Status: Display
Last info: 2002



Farrah Manufacturing Co Inc.
- Registered as N9636C.
Southern Natural Gas Co, Birmingham, AL, 1963-1966.
- Registered as N3035S (1).
Mapco Inc, Tulsa, OK, 1969.
- Registered as N256H (2).
Bancroft Manufacturing Co., McComb, MS, 1970-1972.
Park Meadow Inc/Ligon Air Inc, Ligonier, In.
Garret Corp, Phoenix, AZ, Circa 1979.
- Modified for testing turbine engine in nose.
Garret AiResearch Corp, Phoenix, AZ, Apr. 1983-1988.
- Registered as N25GT.
- Used for engine testing.
Allied Signal Inc, Phoenix, AZ, Dec. 1988-1992.
Struck-off USCR, Jan. 10, 1992.
South Mountain High School, Phoenix, AZ, 1992-2002.
- Donated to Aviation Technology program.
- Displayed.



Serial #: 44-34415
Construction #: 27693
Civil Registration:
N60043, N5002X, N46598 , N900V 
  On Mark Marksman
Name: None
Status: Unknown




Reg'd 12th July 1962 N500X gulf Air Inc, Miami,
30th Jan 63 Intermountain Aviation

1964 On Mark Eng Corp for conversion to on Mark Marksman and re-registered N900V

15th Feb 64 sold to Intermountain Aviation as N900V

Aug 64 Sold to Atlantic General Enterprises Inc

29th March 65 Sold back to Intermountain Aviation

3rd Feb 67 sold to Pan Aero Invest, Reno

5th Feb 67 Sold to Air America as N46598

Officially reregistered as N46598 on 11 April 67 it was ferried to South-East Asia in mid-April 67, then used for training at Udorn from the second half of April to June 67; seen at Udorn April 67 and July 67; between 31 May 67 and 11 June 67. the plane was then ferried from Savannakhet to Udorn and back to Savannakhet, and used for nightly low-level supply drops over Laos, but proved unsuitable for the task, because the aircraft was too fast and too similar to a B-26 bomber.The plane continued to fly for Air America, but just doing transportation flights.

N46598 was then sold to Overseas Aeromarine Inc, Seattle, on 30 March 68, and registered to them as N46598 on 4 April 68, flown to Takhli Royal Thai Air Force Base in mid-April 68; damaged on take-off from Takhli on the ferry flight to the USA in mid-April 68 and burned. The crash was caused by a anti-shimmy poppet valve in the nose strut. The plane had been parked in Laos for several months and had deteriorated badly.

In April 1967, two On Mark Marksman were transferred from Intermountain Aviation, an air service related the US Central Intelligence Agency, to Air America, another air service connected to the Agency. The official role of these aircraft as stated in the specifications provided to Air America from Intermountain in March 1967 was "Aerial resupply, [and] low-level penetration." Both aircraft had been highly modified with a variety of navigation and other electronic equipment for this role.

Between June and October 1967, the first aircraft, re-registered from N900V to N46598, conducted low-level night time supply drops to CIA related forces in Laos during the so-called "Secret War". The program was discontinued because the aircraft was too fast for accurate drops even with the special onboard equipment, and looked too much like a type of strike aircraft known to operate in the theatre. This was cited as often causing forces on the ground to be wary of turning on their marking lamps. The aircraft was damaged on takeoff at Takhli Royal Thai Air Force Base after being transferred to Overseas Aeromarine, Inc.

The second aircraft, officially re-registered from N800V to N67623, was intended for the same role but never used. Both aircraft were initially painted in Insignia Blue, plus white trim areas outlined with black pinstripe that led the type to be nicknamed "The Blue Goose."

In the end, both aircraft were handed over to the 1198th Operational Evaluation and Training (OT&E) Squadron at Norton Air Force Base, San Bernardino, California, a unit known for alleged participation in agent dropping and other clandestine missions in Southeast Asia (Project Heavy Chain). The Squadron evaluated the two Marksman, but apparently found no use for them and scrapped both aircraft, which suffered from a chronic Invader issue of nose gear failure.


Sister ship of N46598

Serial No. - 44-35698

Construction No. - 28987 

Douglas A-26C-45-DT Invader

Participated in Bay of Pigs invasion. 
To civil registry as N5001X.  
Converted to On Mark Marksman N800V, N58071,  N67623.  “Blue Goose” sister ship.

N67623, was intended for the same role as N46598, but never used.


In the end, both aircraft were handed over to the 1198th Operational Evaluation and Training (OT&E) Squadron at Norton Air Force Base, San Bernardino, California, a unit known for alleged participation in agent dropping and other clandestine missions in Southeast Asia (Project Heavy Chain). The Squadron evaluated the two Marksman, but apparently found no use for them and scrapped both aircraft, which suffered from a chronic Invader issue of nose gear failure.