Horten Ho.XIII

History

The German Horten brothers (Walter and Reimar) conducted extensive design studies centered on an aircraft concept known as the "flying wing". This design approach eliminates the traditional tail and replaces it with a hybrid wing fuselage that utilizes significant surface area for lift/drag balance and improved operating range (due to increased internal volume for fuel storage), And include elevators and ailerons as part of the steering main plane design. Their dream was partially realized for the Luftwaffe's jet fighter-bomber Ho IX (Ho 229) at the end of the war (1945), but the Americans pushed it further for a long time in the Northrop XB-35/ XB-49. Strategic range bomber prototype (described elsewhere on this page).

The Northrop B-2 "Spirit" embodies the concept of the modern audience - the stealth bomber still flying today.

Before the end of 1944, the Luftwaffe focused on supersonic fighters to counter the constant threat of Allied bombers escorted by powerful piston-engine fighters. While safe, manned, supersonic flight is still a few years awaymostly in the U.S., U.K., and Russia with programs accelerating in the 1950s and 1960swith the advent of turbojet technology, the concept is considered tentative Accessible - especially in desperate circumstances of the Luftwaffe's war.

In search of a solution capable of reaching speeds of 1,120 miles per hour, the ministry asked ordinary players in the German aviation industry.

At the time, Germany was leading the way in the design and development of turbojets, but all types available at the time lacked the power output needed to produce the desired speed. It has been suggested that turbojets could work well in conjunction with rocket booster motors to help aircraft achieve the desired straight-line speed -- at least for a limited time in the air.

Aside from the obvious technical hurdles, supersonic flight theory is still an evolving field that requires engineers to design planes for things that are largely "unknown" -- because there isn't much concrete data on the inherent dangers and benefits of hypersonic flight available at the time Use -of-sound.

That's no problem for the visionary Horten Brothers, who moved beyond expensive, project-delayed, wind tunnel concepts to full/near full unpowered prototypes. Their method became "Ho. XIII" in physical form. XIIIA Unpowered Glider/Glider. The brothers returned to their Wings approach at Ho.

XIIIA returned the aircraft 60 degrees to the main aircraft to accommodate the expected high speed envelope. The single-seat cockpit is suspended below the frame to provide the pilot with excellent all-round visibility, and the cabin is mounted at the very end of the arrow-shaped fuselage shape.

Dimensions include a length of 31.9 feet, a wingspan of 39.3 feet and an MTOW of 730 pounds.

The program was completed in early 1945, and after just 10 hours of flying in various test flights, the brothers set about putting the project into operation. Ho. XIIIA managed to fly at 110 miles per hour to prove the basic concept was largely sound.

Speaking of the fleshed-out form of the supersonic fighter, the brothers modified the tailless design to include an oversized vertical tail for added stability, the structure proposed to extend the midship forward beyond the trailing edge of the actual fuselage . At its forefront, the cockpit snuggles up in a streamlined fashion - the single-seat position (under the one-piece canopy) is designed to be fully pressurized for working at heights. It is worth noting that the view from the cockpit is blocked by the pilot's fore and aft empennage structures and the main aircraft itself. The main aircraft retained Ho's 60-degree sweep. The trailing edge of the XIIIA has a 30 degree sweep back.

The tail is angled aft 18 degrees, including the rudder and trim plane. Additionally, a modern tricycle landing gear (fully retractable) will be used for ground operation, with the main legs mounted amidships (retracted forward) and the front wheel legs (retracted aft) occupying their usual position below the nose cone.

The flying-wing concept offers the inherent advantage of a larger shared internal volume, which means that the engines and fuel reservoirs can easily be buried deep in the fuselage, keeping the aircraft largely aerodynamic. The jet's air intakes will be either through intakes at the root of the wings or through a single port at the tail and under the nose.

Although the Ho. is not a true flying wing, with the addition of a new vertical tail, the XIIIB retains the advantages of its original full wing area design approach.

Like other postwar German aircraft programs focused on high speed, the brothers sought a hybrid/combination engine configuration that combined the latest German turbojets with a proven rocket booster. This would be the promising BMW 003R, offering 1,760 pounds to 2,420 pounds of thrust, mated to a liquid-fueled Walter HWK 509 rocket for an additional 2,750 pounds of thrust.

The onboard fuel supply will give the aircraft about an hour of flight endurance, with the limited incendiary missile activated/deactivated by the pilot when already flying.

Ho. XIIIB has an estimated top speed of 1,118 mph. Dimensions include a length of 39.4 feet, a wingspan of 39.4 feet and a height of 13.5 feet. Takeoff weight is 17,637 pounds.

The armament is concentrated on 2 x 20mm MG213 internal autocannons, mounted on either side of the nose - this provides ample firepower against any threat of the day.

Although the Ho. XIIIB was expected to enter service in mid-1946, no prototype was ever built for the Air Ministry review until the end of the war for Germany in May 1945. The Ho.

XIIIA glider was discovered by the Allies in its damaged form and eventually destroyed, leaving little trace of the project today.

Specification

Basics

Years of Service

1946

Origins

Nazi Germany

Status

Cancel

Development ended.

Crew

1

Production

0

Manufacturer

Houghton Brothers - Nazi Germany

Operator

Nazi Germany (removed)

Roles

block

The ability to intercept incoming airborne threats with high performance, usually speed and rate of climb.

X-Plane (development, prototype, tech demo)

Aircraft designed for prototyping, technology demonstration, or research/data collection.

Notable Features

Hybrid Unit

Use two or more types of propulsion systems to achieve desired performance/flying maneuvers.

wing sweep

The main plane or leading edge has retraction lines for improved high-speed performance and handling.

High-speed performance

Can accelerate to higher speeds than the average aircraft at the time.

High performance

The ability to fly and operate at higher altitudes than the average aircraft of the day.

Pilot/crew ejection system

Auxiliary procedures to allow pilot and/or crew ejection in the event of an air emergency.

Depression in crew members

Support the pressurization required for crew survival at higher operating altitudes.

Closed crew room

There are partially or fully enclosed crew work areas.

Scalable

Has retractable/retractable landing gear to maintain aerodynamic efficiency.

Dimensions and Weight

Length

39. 4 feet

(12.00m)

Width/span

39. 4 feet

(12.00m)

Height

13.5 feet

(4.10m)

MTOW

17,637 lbs

(8,000 kg)

Main aircraft structure

monoplane/low mount/sweep

Monoplane

Designed to use a single main wing main aircraft; this is the most popular arrangement of main aircraft.

install low

The main aircraft is mounted low on the side of the fuselage.

swipe back

The floor plan features a swept wing along the leading edge of the main aircraft, promoting higher operating speeds.

(structural descriptors refer to production variant Horten Ho. XIIIB)

Performance

Installed:

1 x BMW 003R turbojet with 1,760 lbs to 2,420 lbs of thrust; 1 x Walter HWK 509 liquid fuel rocket booster with 2,750 lbs of thrust.

Max Speed

1,118 mph

(1,800 kph | 972 kts)

Cruise Speed

727 mph

(1,170 kph | 632 kts)

Maximum Speed Diff

+391 mph

(+630 kph | 340 kts)

Ceiling

30,003 ft

(9,145 m | 6 mi)

RANGES (MPH) Subsonic: < 614mph | Transonic: 614-921 | Supersonic: 921-3836 | Hypersonic: 3836-7673 | Hi-Hypersonic: 7673-19180 | Reentry: > 19030

ARMAMENT

PROPOSED:2 x 20mm MG 213 internal automatic cannons in the nose.