Vertipedia - Cierva W.11 Air Horse

The aircraft was designed to provide viable heavy load lifting capability for commercial operations. It employed 3 main rotors all rotating in the same direction. Torque offset was provided by thrust components from the 3 rotors through built-in shaft tilt. The aircraft had a semi-monoquoque structure, a single engine, and a long-stroke undercarriage (5ft) to cope with high rates of descent. A description of the aircraft and its characteristics can be found in the following references,

Source: "The Cierva W-11 Air Horse", J. Gordon Leishman, VERTIFLITE Spring 2003, Page 52

Source: "Discussing the Helicopter", FLIGHT Staff, FLIGHT, December 2nd 1948, Pages 665-668

Overview

Data on design, manufacture and status

Design authority: Cierva Autogiro Company Ltd.

Primary manufacturer: Cierva Autogiro Company Ltd.

Parent type: Cierva Air Horse

Aircraft status: No longer flying

Configuration

Primary flight and mechanical characteristics

VTOL type: Helicopter

Lift devices: 3 in Multi-rotor configuration

Crew required: 2 in Side-by-side arrangement

Landing gear: Wheels (non-retractable)

Key Characteristics

Data on key physical features

Aircraft Details

Data on aircraft configuration, weights, flight performance and equipment

Layout and Dimensions

Weights and Performance

Engine Details

Primary Lift Device

Overall Dimensions
Overall Height:	5.41 m	17.8 ft
Overall Length:	30.05 m	98.6 ft
Overall Width:	28.96 m	95.0 ft

Airframe Dimensions
Airframe Length:
Airframe Width:
Airframe Height:

Landing Gear Dimensions
Landing Gear Base:	6.36 m	20.9 ft
Landing Gear Track:	9.42 m	30.9 ft

Cabin Dimensions
Cabin Internal Height:	1.83 m	6.0 ft
Cabin Internal Length:	5.79 m	19.0 ft
Cabin Internal Width:	2.29 m	7.5 ft

Weights
Max Gross Weight (ground):	7,938 kg	17,500 lb
Max Gross Weight (airborne):
Max Take-off Weight:	7,938 kg	17,500 lb
Empty Weight:	5,384 kg	11,870 lb

Climb Performance
Max Rate of Climb:	7 m/s	1,320 fpm

Hover Performance
Hover Ceiling IGE:
Hover Ceiling OGE:

Limitations
Max Level Flight Speed:	222 km/h	120 kts
Never Exceed Speed:
Service Ceiling:	7,620 m	25,000 ft

Range and Endurance
Max Range:	556 km	300 nm
Max Endurance:

Provided powerplant data is for uninstalled, sea level, static operations.

Powerplant
Number of engines:	1
Designation:	RR Merlin 24 reciprocating
Manufacturer:	Rolls-Royce

Normal Ratings
Max continuous:
Take-off / rated:	1209 kW	1620 hp
Intermediate:
Maximum:

OEI Ratings
OEI contingency:
OEI continuous:
OEI 30-second:
OEI intermediate:

The torque from the 3 rotors was reacted by a moment due to side force from the 3 rotors (front rotor/side-force to port, rear rotors, side-force to stbd)

Main Rotor Characteristics
Diameter:	14.33 m	47.00 ft
RPM:	219.5 rpm	219.5 rpm
Direction of Rotation:	Counterclockwise
Hub Type:	Fully articulated

Main Rotor Blade Characteristics
Blade Construction:	Wooden blades with double taper planform
Blade Chord:
Blade Tip Geometry:
Blade Twist:	-0.205 rad	-11.750 deg
Number of Blades:	3

Main Rotor Derived Characteristics
Disc Area:	161.18 m²	1735.0 ft²
Disc Loading:	16.42 kg/m²	3.362 lb/ft²
Solidity:

Main Rotor Blade Derived Characteristics
Blade area per blade:
Tip Speed:	164.64 m/s	540.2 fps

Tail Rotor Characteristics
Diameter:
Configuration:	Unknown
Direction of Rotation:	Unknown
RPM:

Tail Rotor Blade Characteristics
Number of Blades:
Blade Construction:	N/A
Blade Chord:
Blade Twist:

Tail Rotor Derived Characteristics
Disc Area:
Solidity:

Tail Rotor Blade Derived Characteristics
Tip Speed:
Blade Area (per blade):

References

References and sources used

Discussing the Helicopter

FLIGHT Staff
Flightglobal Archive, December 2nd, 1948 (page 667)
Periodical
The article is a summary of a paper presented by Mr. Shapiro from the Cierva Autogiro Company at an all day meeting of the Royal Aeronautical Society and the Helicopter Association of Great Britain on 20 Nov 1948

The Cierva W-11 "Air Horse"

J. Gordon Leishman
VERTIFLITE, Spring 2003 (page 54)
Periodical
An excellent description of the aircraft, its configuration and technical characteristics