Ahrens AR-404

The AR-404 utility aircraft: was the brainchild of a US company who set up a production facility in western Puerto Rico. The company made various claims for the AR-404, including that it could be certified under the same standards as the large jetliners, but in one year rather than four.  In order to facilitate the loading and unloading of cargo, the fuselage was of constant rectangular section along almost its entire length, the main undercarriage was retracted into sponsons on the fuselage sides, and the tail included a loading ramp. As a regional airliner, the AR 404 was designed to carry 30 passengers, or in its cargo configuration, to accommodate four standard D3 freight containers. It first flew 01/12/76.

Flight International

Through obtaining money from the Puerto Rican government, it was said 1000 locals with no previous aircraft making experience would soon be turning out four per month. A mysterious US government investigation into the company dragged on, preventing the development money and loans going through. The project was abandoned and the principals decamped elsewhere. Only two AR-404s were built. The first prototype was last noted serving as a snack bar.

Crew: 2
Capacity: 30 passengers
Length: 52 ft 9 in (16.08 m)
Wingspan: 66 ft 0 in (20.12 m)
Height: 18 ft 6 in (5.64 m)
Wing area: 422 sq ft (39.2 m2)
Aspect ratio: 10.1:1
Airfoil: NACA 643-618
Empty weight: 9,500 lb (4,309 kg)
Max takeoff weight: 17,500 lb (7,938 kg)
Powerplant: 4 × Allison 250-B17B turboprops, 420 shp (310 kW) each
Performance

Maximum speed: 219 mph; 352 km/h (190 kn)
Cruising speed: 196 mph; 315 km/h (170 kn)
Stall speed: 86 mph; 139 km/h (75 kn) (flaps down)
Range: 978 mi; 1,574 km (850 nmi)
Service ceiling: 18,000 ft (5,486 m)
Rate of climb: 1,200 ft/min (6.1 m/s)

Lippisch DM-1 Glider

At age 14, Alexander Lippisch (1894-1976) was inspired to work in aeronautics after witnessing Orville Wright demonstrate flying over Berlin in September 1909. Shortly after World War I, Lippisch became involved in sport gliding. He designed several conventional sailplanes, and between 1927 and 1932, he built eight tailless glider and powered airplanes. Exhaustive work with flying models preceded the full-size aircraft.

In 1939, Lippisch joined Willy Messerschmitt's aircraft design and manufacturing firm where he developed the Me 163 Komet (see NASM collection), a semi-tailless, rocket-propelled, fighter interceptor. This small fighter possessed tremendous speed and on October 2, 1941, test pilot Heini Dittmar reached a velocity of more than 1,000 km/h (620 mph) at the controls of his '163. When mated to Lippisch' swept wing airframe, the Walther rocket motor could push the Komet through the air faster than any other man-carrying, flying machine flown to that date. Despite such performance, the motor consumed fuel at a fantastic rate and the range of this airplane was too short for practical wartime use. The Messerschmitt factory completed about 300 Komets. The performance of the Me-163 encouraged Lippisch to experiment with flight at velocities beyond the speed of sound, about 1,124 km/h (698 mph) at 6,080 m (20,000 ft) above the ground. In 1943, Lippisch became director of the Luftfahrtforschungsanstalt Wien (the Aeronautical Research Institute at Vienna or LFW) and he began to develop the supersonic delta wing airframe. Lippisch created several designs that culminated in the DM-1 (Darmstadt-Munich model 1) glider. Lippisch intended to test the DM-1 to determine the handling characteristics of a sharply swept delta wing aircraft flying at low speeds. After completing these tests, he planned to add power and continue to test the DM-1, pushing it to higher speeds to investigate high subsonic and supersonic flight. Lippisch hoped to reach Mach 6 (6,743 km/h or 4,188 mph). Construction began in August 1944 at the Flugtechnische Fachgruppe (FFG) Darmstadt but an Allied bombing attack during September interrupted the work. Workers moved the project to the FFG Munchen and continued to build the delta plane. The war ended and the Allied armies discovered the unfinished glider when they occupied the base at Prien am Chiemsee in southern Germany early in May 1945. The specialists in U. S. air intelligence were deeply impressed with the DM-1 and arranged for construction to resume and continue throughout the summer. A number of people visited the project site including Charles A. Lindbergh. The aircraft was completed late in the summer and Allied authorities planned to test fly the aircraft in Germany, but they wisely reconsidered and chose to ship the glider back to the U. S. Workers loaded the DM-1, fully-assembled, into a special crate and began to move the aircraft on November 9, 1945. The glider arrived at Norfolk, Virginia, aboard a frieghter and its journey ended at the National Advisory Committee for Aeronautics (NACA) Langley Aeronautical Laboratory. Wind tunnel tests began in February 1946 and finished by year's end. The NACA transferred the DM-1 to the National Air Museum (later the National Air and Space Museum) in 1950 and the glider arrived at Silver Hill, Maryland, in 1954. Wingspan: 5.9 m (19 ft 5 in) Length: 6.6 m (21 ft 7 in) Height: 3.2 m (10 ft 5 in) Weights: Empty, 297 kg (655 lb) Gross, 460 kg (1,017 lb) Info by Frank Carr, Russ Lee, 4/11/11

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