Autogyro's, gyrodyne's and helicogyre's

Autogyro's

If you know what an autogyro is, then your probably seeing something akin to the above image in your head (don't you just love how the illustrator has given Bond the classic Bond pose even though he's cleary flying, whilst being shot at, firing his own machine gun and launching two missiles). The aircraft in that picture is the classic British 'Wallis design' of the 1960's. More about that later.

Autogyro's, gyrocopter's and helicogyro's are all aircraft which use rotor blades to stay up in the air, but which aren't helicopters (in other words they usually can't hover or take off vertically).

The most simple difference between a gyrocopter and a helicopter is helicopters have powered rotors and autogyro's don't. Autogyro's work by means of air passing over the rotor blades, making them spin and in return giving the aircraft lift. Aeroplanes use their wings for the same purpose. Lift is what keeps air craft in the air. The autogyro was invented in 1923 by the Spanish aero-engineer and pioneer of flight; Juan de la Cierva who had been trying to build a three engined bomber for the Spanish military, but who found to his dismay that it kept stalling (in other words the aeroplane lost lift). In order to deal with this, Cierva turned to some designs he'd been playing with the year before, and in 1923 he managed to build the worlds first functioning autogyro, the C-4 (thats it in the picture below taking off for the first time in 1923). When the engine of the C-4 stalled, as engines were also wont to do quite often in those days, the C-4 was still held aloft by the 'autogyration' of its rotors, and still had sufficient lift to glide safely down to the ground with ease.


Cierva continued to build autogyro's, spending all his remaining money on the next prototype, the C-5, and then getting a grant from the Spanish military for the C-6. These aircraft were still experimental though and real funding was needed. A Scottish industrialist named James G. Weir stepped up and together they founded the Cierva Autogiro Company, in England. Cierva, now with real funding started producing more and more sophisticated aircraft, improving his designs one after the other. The British government got interested as did an American industrialist named Harold F. Pitcairn who set up his own licensed manufacture of autogyro's in the USA. Focke-Wulf of Germany were also very interested and were granted a license to manufacture their own variant and the Third Reich was eager to assist other aero-designers to build new and interesting aircraft also.

In 1929, Cierva tested the C-19, by far his most advanced model as it could start its rotor spinning prior to take off (thus giving the C-19 the ability to take off on a shorter run way). Up until this point, Cierva had been building his autogyro's as if they were fixed wing air craft and relying on control surfaces to steer the vehicle. This meant, at low speed the pilots lost their ability to control the aircraft as control surfaces require a flow of air in order to function. The slower the speed, the less air flow and the autogyro's become more difficult to control. Cierva solved this problem by developing a direct control rotor hub that allowed the rotors to be individually tilted and thus made the rotor the primary method of steering as opposed to control surfaces on wings. Since the rotor was always turning (thanks to autogyration) this mean the aircraft could now be steered at very slow speeds and thus the pilots wouldn't find themselves losing control as they came into a slow landing.

A C8 above Bryn Athyn Cathedral

What this meant in practical terms was, the autogyro could take off and land on extremelly short air strips thus giving the autogyro a decided advantage over fixed wing aircraft. They still couldn't take off and land vertically, like helicopters can, but in the 1930's helicopters were still a decade away from stealing the show and autogyro's were in their golden age.

Like so much of that era, it all came to tears in 1939. The Second World War eventually did away with the autogyro as a practical aircraft. People came to see them as clumsy, inefficient and just not worth the bother. I get the feeling that a lot of people were influenced by the sleek and sexy designs of fixed wing aircraft and so these were developd to a far greater degree. Fixed wing aircraft also had fewer moving parts and were more practial to boot. Fixed wing aircraft production sealed the fate of Cierva's designs, relagating them to the cheap seats and Cierva himself was killed in a plane crash in 1936 thus ending his innovation. The only significant autogyro design to come from the Second World War was the unpowered German Fa-330, designed to be towed by a U boat and used as a look out post (I bet that was a cold duty). The FA-330 was designed to be broken down and stowed inside the U boat so it was very small and easily taken apart (see below). Its fascinating to watch given that the only thing keeping the Fa-330 up in the air is the forward motion of the U boat.

Fl-184

The Japanese had a variant of the same idea and the British used their autogyro's to calibrate their coastal radar defences, but on the whole the autogyro was eclipsed by other aircraft designs and became an obscure curiosity. The Germans had played about with numerous designs, including the Fl-184 anti submarine prototype but after the war was finally finished, things looked bad for future autogyro development. Times had changed and the helicopter had arrived to steal the thunder. That was until a Russian immigrant in the USA named Igor Benson came across an FA-330 and was motivated by its light weight simplicity. Benson designed his own version, the B-5 which was designed to be pulled behind a car, presumably along beaches. Later he added light-weight motors to his designs and finally in the 1950's he had perfected them with the B-8. The USAAF tested the B8 as a possible aircraft escape vehicle under the designation X-25b (which makes it sound very grand) but nothing much came of that.

X-25b

Crew: 1
Dimensions- Span: 22 ft, 8 in; Length: 11 ft, 3 in; Height: 6 ft, 3 in
Max Speed- 95 MPH
Range- 84 miles
Max Altitude- 15,000 ft
Power Plant- One McCulloch 4318 piston engine with 72 hp
Weights- Empty: 247 lbs; Loaded: 550 lbs

If you consider the autogyro's design evolution, you can see how the FA- 330 set the template for the next fifty years. The 'next major design' after the B-8 is the Wallis autogyro (as seen in the James Bond poster at the top of this post) and it has very little innovative difference from its predecessor. Ken Wallis spent a lot of time and effort trying to sell the idea of the Autogyro, as a military reconnaissance platform, but no one was really interested. The Wallis design, like the B-8 is a small, buzzing little thing, eccentric and dangerous to behold. A few attempts at building commercial variants went no where. Wallis's most spectacular successes came from Hollywood, where both James Bond and Mad Max made use of autogyro's, in equally unrealistic fashion.

Gyrodyne's

Fairey Rotodyne

A gyrodyne is a hybrid between the autogyro and the helicopter. Like a helicopter it has a powered rotor, and can subsequently hover and take off and land vertically. At least in theory. In practice the levels of power needed mean gyrodynes have been few and far in number and those that were built, used a run way to take off. The story of the gyrodyne starts in the golden age of the 1930's (of course!) when a German aircraft designer named Anton Flettner got involved in building helicogyro's (see below) and autogyro's. His first practical model was the Fl-184 anti submarine prototype (see above) which crashed and burned in 1936. The Fl-184 and its successor the Fl-185 were based on the autogyro idea of forward propulsion using additional propellers, but unlike Cierva, Flettner powered his rotors, effectively making them into gyrodyne's.

Fl-185

These designs eventually led to the famous Fl-282 Kolibri, which is sometimes considered the first practical helicopter, though technically it is a synchropter as it had two intermeshing rotors.

Dr. James Allan Jamieson Bennett, who had become Chief Engineer of the Cierva Autogiro Company after Cierva's death, took the next step. Bennet took Flettners idea and made a prototype gyrodyne which had a shaft-driven rotor with torque correction and propulsion for translational flight provided by a side-mounted propeller. In other words, it had a second prop to stop it from spinning out of control, just like a helicopter but in this design the second prop also provided forward propulsion. Bennett's concept led to a redefinition of what a gyrodyne was as it acted like a helicopter when landing and taking off, but flew like an aeroplane. The most immediate practical application of this came in 1946, when Bennet's design led to the creatiion of the Fairey FB-1 Gyrodyne (see image below).

Crew: 1
Dimensions- Span: 15.7m. Length: 7.62m. Height: 3.10m
Max Speed- 225km/h
Power Plant-1× Alvis Leonides 9-cylinder radial piston engine, 520 hp (388 kW)
Weights- Empty: 1,633kg. Loaded: 2,177kg.

The FB-1 was never more than a pair of protype's, but they demonstrated a wide range of record breaking capabilities. Enough for a new variation to be built; the jet gyrodyne of 1954, which was a gyrodyne with small jets at the tips of its rotor wings (technically this also makes it a helicogyre)

Events bring us now to the Fairey Rotodyne (see image above). Without a doubt the crowning glory of all western autogyro's, gyrodyne's and helicogyre's. Designed to carry passengers, or as a military cargo carrier, the Rotodyne first flew in 1957. It could land like a helicopter and had the cruising speed of a fixed wing aeroplane. It excelled in trials but was killed due to post war politics which saw American designs take precedence.

Crew: 3 + 40 passengers
Dimensions- Span: 15.7m. Length: 7.62m. Height: 3.10m
Max Speed- 343km/h
Range- 830 km
Power Plant-4× rotor tip jet burning compressed air/fuel2× Napier Eland turboprops, 2,800 hp (2,100 kW) each
Weights- Loaded: 15,000kg. Max: 17,000kg

Whilst all this was going in the west, the Soviets were busy with their own, parrallel development. The Kamov Ka-22 was the resulting monster. As far as I am aware, it had no commercial purposes.

Crew: 5
Dimensions- Diameter: 22.5m. Length: 27m.
Max Speed- 350km/h
Range- 830 km
Power Plant-2 × D-25VK turbo shafts, 4045 kW (5500 hp) eachCapacity: 16,400 kg
Gross weight: 42,500 kg

Helicogyro

Link

A helicogyre is a helicopter or Autogyro which uses small propellers or jets to turn its main rotor. Naturally, as this was very unweildy, such aircraft never got past the design stage, but as the jet gyrodyne, the Hiller Hornet and the Fairey Rotodyne demonstrate, the idea wasn't without some merit.

Some personal designs...

There is no conceivable reason why a large, fully developed autogyro couldn't be designed ...save for costs and practicality. As a consequence of this, I have drawn a couple of my own designs (for my friend Oleg's RPG campaign 'Dog star'). These frivolous twin boom designs are based on numerous pre-existing fixed wing aircraft designs, especially the B-25, the P-38 the OV-10 and the P-61. I doubt they'd actually work, but I like the idea of autogyro's and its interesting to wonder what might have been...

Valkyra is a Dwarven transport autogyro with combat capabilities. She can carry 10 soldiers in her cargo compartment, plus two passengers in her uppermost deck. The crew sit in the primary cock pit and a single gunner/bombadier sits in the nose.

Lightning is a smaller, faster, gyrodyne. It has three engines, two pulling and one in the rear of the fusilage which powers the pushing prop and gives power to the rotor. The idea is, with long range drop tanks, Lightning would be able to cruise to the fight, then discarding its tanks power up the rear propellor and accelerate to combat speeds. It has a crew of two. A pilot in the nose and a navigator/specialist in the rear.