Horten Ho 229 V3


How is the Horten Constructed?

The Horten stands 2.7 meters (9 feet) tall, has a 16.8 meter (55 foot) wingspan, and is 7.6 meters (25 feet) long. It is constructed in five main sections: a center section constructed from a steel tubular framework that encompasses two engines, the cockpit, the landing gear, and two wings. The center section framework is covered with a plywood skin made up of multiple panels that are attached to structural wooden supports with steel hardware. Steel fairings protect the engines and overlay plywood at the back of the aircraft to protect the wood from exhaust heat. A green colored protective coating, that may have been a fire retardant, is present on the interior surfaces of the plywood panels and selectively on the exterior wooden surfaces. The wings are constructed of wooden structural members and plywood skin.

Structural Framework

The structural framework of the jet is made from tubular ferrous alloy sections welded together. Large bolts, in addition to castellated nuts and cotter pins, are used to join the framework top and bottom sections to the front and aft landing gear, wing roots, wing pins, and the nose sections. The circumference of the larger structural tubes are 15.9 centimeters (6 1/4 inch) and smaller connector tubes are 10.2 centimeters (4 inches) in circumference. U-shaped brackets are welded onto the structure in multiple locations for the purpose of adjoining either the plywood skin or other structural elements. Each of the U-shaped brackets vary in length depending on their location on the wing roots and have floating nut plates on the top of the framework, while the bottom section has self-locking nut plates. The nut plates appear to be made of an aluminum magnesium alloy.

Drawings highlight each wood panel section of the bottom of the aircraft.

Drawings highlight each wood panel section of the top of the aircraft.

Plywood Skin

The plywood covering the airframe consists of pre assembled panels that vary in shape and size. The plywood gives the jet its overall aerodynamic shape and is formed with the thickest sections (1.9 centimeter, 3/4 inch) at the leading edges which appear to tapper to the aft where the plywood is .3 centimeters (1/8 inches) thick at the tail. The placement of the engine fairings obscures the sections where the plywood panels meet and gives the jet the appearance of an uninterrupted streamline shape. The top of the jet has nine individual plywood panels, and the bottom has four—not including the tail.

Each plywood panel was constructed with lumber structural supports, called "formers," that affix to the plywood with nails. The formers also have a thick adhesive bead that runs along the edges where the wood interfaces with the surface of the plywood. These formers fit into the U-shaped brackets of the steel framework.

Stacks of wood veneers that are largely adhered together are placed in between the plywood skin, the U-shaped brackets along the wing roots, and on the belly panels. These stacks are used as spacers to compensate for material and possibly provide more anchorage for hardware.

The right and left curved leading edges of the jet are fabricated differently from the rest of the jet. In these sections the formers are attached to the steel framework with bolts, and the L-shaped brackets are riveted to the formers. Each L-shaped bracket has riveted nut plates for attaching the plywood skin.

Engine Fairings

The engine fairings, intake cowlings, and exhaust panels are made from welded pre-cast sections of steel. The intake cowlings appear to be made from hammered curved sections welded together to fit over the plywood leading edge. The intake cowlings have a small, concave underbelly section that screws to the main curved piece and to surrounding plywood on the underside of the leading edge.

The fairings on the top of the jet are curved to match the contour of the engines and have 5.1-centimeter- (2-inch-) wide flanges on either side with regularly spaced holes for hardware (machine screws) to secure to the plywood. The fairings on the top of the jet occur as two sections, one forward and one aft. The aft sections are appreciably longer.

The exhaust panels, located at the aft, are made from long and flat sections of steel with a hammered concave area located directly behind the engine. The exhaust panels are secured to the plywood with machine screws that connect on the underside with magnesium alloy nut plates (at the very aft of the jet), the other hardware securing the exhaust is machine screws and some wood screws.