1091

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

http://aviastar.org/helicopters_eng/landgraf.php

http://en.wikipedia.org/wiki/Landgraf_H-2

http://helicopterfoundation.org/portals/4/jim.pdf

I was impressed with one of them, the Landgraf machine. So much so that I later went to work for the Landgraf Helicopter Company, and later became their Vice-President.

I had soloed in the Landgraf helicopter. After I took training in the Bell machine, it really frightened me because if I’d gotten into a Bell or Sikorsky and tried to fly it solo with just airplane experience I would have crashed for certain. Because these machines have a lag in the controls that you have to get used to, and the Landgraf machine used blade ailerons for control, which gave you an almost instant control like an airplane, I was able to get away with that one.

Rotor-Craft X-2 Dragonfly / XR-11 This makes reference to Landgraf.

Landgraf Patent: 2,443,393 This appears to include all of his unique ideas.

US 2614637 ~ Air Screw with Automatic Pitch Mechanism ~ Fred Landgraf

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 and from the patent. This is the opposite of line below.

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

Tie-Rod Transmission ~ An Ingenious Drive System Used on the Landgraf Helicopter

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. There appears to be drag tabs at the blade tips, presumably for yaw. turn. This is the opposite of line above.

Worm & Wheel(s):

He uses a worm and 2 wheels. Flettner proposed a worm and 2 wheels for his Fl 339 See 1509.html

The worm's shaft could be extended forward or aft to drive a propeller.

Fred Landgraf (seen misspelled as Langraff and Langgraff).

Article from AMERICAN HELICOPTER October 1946