Rotor-Craft Corp. projects

Out of the myriad helicopter companies that mushroomed in the immediate aftermath of World War II, few actually managed to exist for more than a handful of years. Among these, the Rotor-Craft Co. (later Rotor-Craft Corp.) of Los Angeles , Calif. (later Glendale) was created in 1946 but soon disappeared into oblivion. And yet it was a proponent of several very interesting designs, some of which even were tested in prototype form by the military.

• The two-seat X2A Dragonfly prototype, powered by a Continental A100 engine, was purchased by the Army as the XR-11 (later XH-11), with serial 45-9478 and tested in 1948. The company envisaged a large plexiglass cabin on the production variant, but the prototype had none of it and was pretty basic by comparison. It is unsure if it actually flew as no pictures of it in flight seem to exist.
• The ambitious Model 20 Rotorbus, an enlarged civilian derivative of the Dragonfly with 1,500 hp total power, which was to accomodate 24 passengers.
• The Heli-Jeep, a two-seat twin-rotor project mentioned circa 1950, which may or may not have been built.
• An unidentified prototype which may have been the forerunner of the RH-1.

• The rocket-powered RH-1 Pinwheel, a diminutive one-man, strap-on-the-back helicopter which was evaluated in 1954 by the Navy's NATC at Patuxent River.

Sources: The American Helicopter, Aerofiles.com

NOTE: Rotor-Craft is NOT to be mistaken for the later British company Rotorcraft (in one word) which produced the Grasshopper.

I knew I had it somewhere... just found it. Here's the only pic I know of the actual XR-11 (XH-11) prototype. Caption says that it began testing in 1948 but was destroyed in an accident. It also adds that nothing is known of its development, and that the company has been working on a "Heli-Jeep" for U.S.A.F., which is said to be also a tandem-rotor design.

Source: Interavia 1951, N°3

From JAWA 1947,

there was also a two Projects,a four-seat and a a twelve-seat developed from XH-11,beside
twenty four-seat Project.

Assuming that the XR-11 relied on normal control mechanisms, the inputs must have been transmitted to the rotor heads internally through the rotor shaft. I can imagine some downsides to that approach.

taildragger said:

Assuming that the XR-11 relied on normal control mechanisms, the inputs must have been transmitted to the rotor heads internally through the rotor shaft. I can imagine some downsides to that approach.

Click to expand...

For the live of me I cannot remember where I read that the Rotor-Craft XR-11 used not only the mechanism but the actual parts from the Landgraf H-2, which Magill had purchased after Landgraf Co. had folded. The H-2 blade pitch was controlled by some type of ailerons at the end of the blades.

Couldn’t find any more detailed close-ups of the XR-11 blades than the one below (right), as compared to the Landgraf H-2’s (left).

There is another strap-on tipjet helo by Gilbert Magill‘s Rotor-Craft: the One Man Rocket Rotor.
It is different from the Pinwheel designs as it has no frame or legs to stand on the ground.

„A one-man 100 lb helicopter, powered by rockets in the tips of two small rotor blades, would be tested soon by the navy, it was announced to-day. It is the nearest approach that has been made to [strapping] a pair of rockets upon the back of a man and shooting him into space “comic strip fashion,” said the designer (Mr. Gilbert Magill).
The liquid fuel rockets, he said, were controlled by a throttle. The rotors were fixed to a [steel] tube which supported fuel tanks and an open air pilot’s seat.” Cairn’s Post, October 24, 1951.

There was also a feature article in Popular Science of January 1952.

Hi,

the exclusive of its designs are as following,

Dragonfly,X-2A,Heli-Jeep,RH-1 Pinwheel,XR-11 (XH-11),Model-20 Rotorbus,Unknown-Prototype,Four-Seat Tandem-Rotor and Twelve-
Seat Tandem-Rotor.

Honestly,I am far away from my home,so I can't judge if there is more concepts or not.

Some time ago I came across a Hiller Aviation Museum YouTube channel, and there I found couple of videos which clearly show not-Hiller helicopter. Now I realized they most likely show some early versions of RH-1 Pinwheel.

Here they are:
View: https://youtu.be/IJYI-65AYRc?t=85

View: https://youtu.be/oN7xhUIvbsA?t=71

View: https://youtu.be/kmlEw-t9Xc4

hesham said:

Hi,

the exclusive of its designs are as following,

Dragonfly,X-2A,Heli-Jeep,RH-1 Pinwheel,XR-11 (XH-11),Model-20 Rotorbus,Unknown-Prototype,Four-Seat Tandem-Rotor and Twelve-Seat Tandem-Rotor.

Honestly,I am far away from my home,so I can't judge if there is more concepts or not.

Click to expand...

From Bill Gunston's book.

From, Military_Review 1951-52

Armin Derer said:

For the live of me I cannot remember where I read that the Rotor-Craft XR-11 used not only the mechanism but the actual parts from the Landgraf H-2, which Magill had purchased after Landgraf Co. had folded. The H-2 blade pitch was controlled by some type of ailerons at the end of the blades.

Couldn’t find any more detailed close-ups of the XR-11 blades than the one below (right), as compared to the Landgraf H-2’s (left).

Click to expand...

So a variant of the “Flettner tab” that Kaman out into large-scale production on Husky, Sea Sprite, etc.