Item 1091
OTHER:
Helicopter - Outside - Interleaving - Landgraf ~ H-4
Outside Web Pages:
http://avia.russian.ee/helicopters_eng/landgraf-r.html
http://www.aerofiles.com/landgraf.jpg [X21762]
http://avia.russian.ee/vertigo/landgraf-r.html
Landgraf Patent: 2,443,393 This appears to include all of his unique ideas.
Notes:
LANDGRAF A certain Fred LANDGRAF, influenced for the Focke-achgelis Aircraft, initiated in 1938 the construction of an aircraft of a place and two lateral rotors, the H2. The adjustments had been laborious, the aircraft if it caused an accident during the test flights, flying for the first time in November of 1944. This must have been a convincing flight, therefore the Landgraf got a contract of the American army to develop the H-2. this aircraft weighed 386 kg, in full load, and was stimulated for an engine of 85 horses type R.POPJOY. The control of the ciclico was gotten through compensation mechanism, and the two rotors did not intervene. Prominence for the set of landing gears, that were retractable. An accident damaged the aircraft sufficiently, stopped the activities of the company, who closed the doors in 1948.
1943: (Fred) Landgraf Helicopter Co, 135 St at Central Ave, Los Angeles CA.
H-2, -3, -4 1944 = 1pCH; 85hp Pobjoy R; span: 27'0" rotor: 16'0" length: 15'0" load: 186# v: 100/x/0. Fred Landgraf; ff: 11/2/44. Twin overlapping rotors on wingform pylons. $2,300; POP: 1 [X21762], produced as military evaluation prototype, damaged in a test flight. Company, beset by financial problems, cancelled development of 3p H-3 and 5-8p H-4, and auctioned its design and tooling in 1949, with the remains of the prototype going for $50.
The airfoil of the blade is NACA 0015.
It looks like the rotors turn inside-forward (breaststroke). This is assumed by looking at the shade of the blades in one of the pictures.
It appears that the craft has a torque ~ pitch coupling.
It appears that yaw is by differential torque.
Gross weight: 850 lbs
Pitch - RRPM governor
Landing gear
Additional information is available in 'The Helicopter ~ A pictorial history' page 150.
Have book.It has more specifications, such as 18 ft dia. rotors (5.5 m also mentioned) disks at a 12 ft stagger (3.6 m also mentioned) (interleaving).
Additional information is available in 'Mechanix Illustrated'. Have copy in file folder.
The rotors' advancing blades are on the outside. Their appears to be drag tabs at the blade tips, presumably for yaw. turn .
Fred Landgraf (seen misspelled as Langraff and Langgraff).
Article from AMERICAN HELICOPTER October 1946
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There is the Landgraf H-2 portion of an article in the same file.
There is the Mechanix Illustrated Jan 1949 article in the file folder
More Information on the Interleaving Configuration:
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Last Revised: June 14, 2008
