Douglas A/B-26 Invader

On Mark interior layouts

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The On Mark airstairs and cabin access, By Richard E. Fulwiler - Main page

Interior and Cabin details for the On Mark Marketeer and Marksman conversions
On early examples and even some of the later On Mark conversions, some aircraft did not incorporate the circumferential “ Ring “ rear spar, and had the belly Airstair as the entry portal.
The cabin was broken up into compartments that limited comfort and ease of movement.
On Mark was able to open up the interior considerably with the incorporation of the rear “ Ring “ spar that eliminated the original aircraft’s carry-through structure / partial bulkhead. This option first appeared on the prototype Marketeer, N40Y in 1957. The ring spar eliminated the difficulty in having to duck under the rear spar carry-through structure, and to navigate around the area in the cabin floor for the bottom entry door. Ring spar optioned versions of the Marketeer, and all Marksman conversions had the starboard side Airstair entry door, and the mid-cabin seats could now be mounted on tracks to allow arrangement flexibility and ease movement about the cabin. On Mark named their interior arrangement options as " The Director ", " The Administrator " and " The Secretarial " .
The Invader’s fuselage width was so narrow that passing between two adjacent seats was very difficult, so was usually avoided. To compensate, On Mark designed the cabin to have a long couch installed along the port side with it’s back bisected by the ring structure, or individual chairs installed fore and aft of the rear spar. The couch or these individual chairs faced to starboard. Two opposite footwell windows below the wing gave the passengers seated there a view out from that mid-section seating area. The fully enclosed lavatory ( when optioned ) was port-side forward just behind the aft face of the forward spar bulkhead, and was just big enough to have a very small wash basin on the forward wall and a chemical toilet installed in the aft-portside area. There was just enough floor space to stand ( on the Marketeer and early Marksman conversions, stoop ) at the wash basin just inside the angled privacy door, and the closed toilet lid made for a jump-seat.
The aft most seat pair ( double seat ) was just far enough forward of the rear cabin bulkhead to allow reclining to around 20 degrees from vertical. As the fuselage was beginning to further narrow in this area, these seats were very close together and shared a center armrest. Retractable footrests could be extended forward from beneath the rear double seats on most conversions for comfort. Work tables were held in wood paneled pockets along the outboard sidewalls, lifting up and folded out horizontally to bridge across the cabin for use by the rear and aft-intermediate cabin seat occupants. These intermediate area seats ( mounted on tracks for fore-aft adjustment ) could be positioned facing either forward or aft, individually or in pairs. Large cabin windows were installed in the fuselage sides for these passengers. Small “ brow “ type windows were installed in the fuselage above the wing to brighten this area of the cabin. Curtains were usually installed and could be drawn closed to cover all cabin window openings.
Beverage and food service consoles could be optioned and were usually installed on the cabin’s starboard side, inboard of the wing root area. Entertainment equipment, and flight status instruments could also be included, tucked into small consoles between seats or on dedicated panels. Emergency escape hatches were provided in the cabin overhead.
Whatever interior arrangement was chosen, entry to the cockpit-flight-deck was accomplished by ducking under the forward spar through an opening on the starboard side. The cockpit floor was the ceiling of the nose gear well and therefore elevated from the cabin floor. An angled bulkhead extended from the top of the aft nose gear well bulkhead, rising up to the base of the forward wing spar carry-through. This panel was solid for 2/3rds of the width towards the port side, open on the starboard 1/3rd for cockpit entry. The cockpit jump seat ( when optioned ) was mounted on the port side behind the pilot.
All interior appointments were of the highest quality and comfort levels. On Mark worked with each of their customers to provide an environment that was as unique, plush, and as quiet as possible. These interiors far exceeding the standards of the best the airlines had to offer, and set an example for other business aircraft to follow.


Photographic legend
    • Early Executive Marketeer N2DM ( with rear spar carry-through )
    • Marketeer N40Y (  the prototype Marketeer, with rear ring spar )
    • Marksman N827W ( Marksman #2 )
    • Marketeer N26BK ( rear spar carry-through )
    • Marketeer N7079G ( rear ring spar )

Early Executive ( Marketeer ), N2DM ( rear spar carry-through





Marketeer N40Y (  the prototype Marketeer, with rear ring spar )



Marketeer N40Y - Mid-Cabin - view forward, Lavatory door closed. Forward ( Main ) Spar " duck-under " evident.


Marketeer N40Y - Cabin - view aft, Airstair open.




Marketeer N40Y - Cabin - view aft, Airstair closed, work tables extended.


 Marksman N827W ( Marksman #2 )


Marksman N827W - Cabin - view aft. Note the Rear " Ring " Spar covered by upholstery.


Marksman N827W - Cabin - view forward. Note the Rear " Ring " Spar covered by upholstery, the Forward ( Main ) Spar carry through with " Duck-Under " below right, and the curtained opening above the covered structure.

Marketeer N26BK ( rear spar carry-through )
Graham Robson photos, used with permission.




Marketeer N7079G "Sexy Sue" ( rear ring spar )