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Hafner Rotachute, Rotabuggy
had watched the development of parachute forces in first the Soviet
Union and then in Germany with a certain amount of amusement,
such forces could be easily picked off while still in the air or
quickly surrounded by superior forces once on the ground. The success
of the German Fallschirmjäger,
Norway and then in Holland quickly forced an reappraisal.
The British swiftly organised parachute troops of their own, largely
copying the techniques they observed the Germans to use. However they
were also keen to "leap-frog" the technology used by the Germans in any
way they could. We
are so familiar with seeing
modern parachutists descend
with accuracy onto tiny targets that it is easy to forget that in the
Second World War the parachutes of the time did not allow much control
at all. Paratroops had to largely trust to luck as to where they would
land. German parachutes featured a single strap that the wearer dangled
from and were particularly hard to control, the British and American
parachutes featured a much better harness and had a bit better control,
but nothing like the control modern parachutes allow.
Hafner an Austrian
autogyro pioneer who had settled in
Britain to develop and sell his AR
Gyroplane. In 1938 in response to Air
Ministry specification S22/38 he had submitted
designs for a three seat autogyro (the AR IV and a sub-variant the AR
V) to be used by the Royal Navy. The design was accepted and
construction had started (by Short Bros) when in May 1940 Hafner was
interned as an "enemy alien". He was quickly released and became a
British subject. For some reason he did not proceed with the navy
autogyro project when released. Instead his work switched to the
problem of producing a more controllable alternative to the
parachute. He thought he could use the autorotation principle of
the autogyro to produce an unpowered rotor alternative to the parachute
that would allow much greater control and and accuracy. It had obvious
applications for dropping spies and saboteurs behind enemy lines and
also for surprise coup de main operations to seize or destroy
in enemy territory. He presented his ideas in September 1940 and they
were enthusiastically taken up. Hafner set up a team at the Airborne
Forces Experimental Establishment based at Ringway (now Manchester
development of the early
Rotachute. On the left is the device as originally conceived, worn on
the back like a parachute with folding rotor-blades that would spring
open when the wearer jumped from an aircraft. Static tests showed a
lack of directional stability which led to the middle development which
featured an inflatable fin blown up once in flight by compressed air
(like a life jacket) and kept rigid by air captured in
side-pockets. More tests showed this still did not have enough
directional stability so further development led to the Mk I Rotachute
on the right which used a metal framework to hold the pilot. The tail
was still a bag of rubberised fabric held rigid by the airflow into it.
The Mk I was the first Rotachute to actually take to the air with a
pilot, albeit only towed behind vehicles. It proved that even more
stability was needed. Note that the Mk I featured the ability to mount
a Bren gun under the pilot. It was envisaged this could be fired via a
cable to give covering fire during the final stage of landing and then
be disconnected to be used once on the ground.
led via the Mk II and Mk III to
the MK IV, the ultimate Rotachute. This had a rigid fin and small
endplates on the tail to give the required stability.
Tests at Ringway, involving rotors with dummy loads towed behind
vehicles or dropped from aircraft, soon showed that the initial hopes
a simple foldable rotor worn like a parachute were impractical. It soon
became apparent that a fin of some sort was needed to give the desired
directional stability. At first it was hoped that a small "blow-up" one
would suffice, but further testing proved it needed to be larger and to
support the fin a metal framework was needed that the wearer would sit
in. Time dragged on and the first towed test of a Rotachute with a
pilot on-board (the Mk I piloted by Sqdn Ldr I. M Little towed behind a
Humber car) did not take place until 11th February 1942. The Mk I led
to the Mk II which featured an even larger fin (albeit still
essentially a rubberised bag kept inflated by air flowing into it).
This in turn led to the Mk III with an even larger fin, this time
manufactured as a self-supporting structure complete with small
tailplane. The Rotachute had grown from the initial idea of a small
strap-on parachute alternative, worn by the "wearer" into a tiny
unpowered gyrocopter flown by a pilot.
Testing of the numerous prototypes continued, progressing from towing
behind cars and trucks to being towed behind Tiger Moth aircraft (in
for 40 minutes). Squadron Leader Little was joined in the testing
programme by Robert
Kronfeld the renowned glider
pioneer. The fitting of endplates to
the tailplane of the Mk III in May 1943 finally produced a craft that
performed well in all respects. However by now it was late 1943 and the
problems of actually delivering the Rotachutes to the target area for
the assault role had not been addressed. Also the growth in the
structure of the Rotachute had made it unattractive for delivering
spies and saboteurs (its one thing to quickly bury or hide a parachute
after landing, quite another to dispose of the tiny aircraft the
Rotachute had grown into). In the meantime the British had already used
gliders carrying troops to seize bridges during the invasion
Sicily and there seemed little point in carrying on with Rotachute
development. There were various spin-offs that were explored; an
unmanned Rotachute style device was suggested as an alternative to
parachutes for delivering air-dropped sea-mines and supplies and an
unmanned Rotachute towed behind a ship as an alternative to a barrage
balloon was another. Paradoxically the use of the Rotachute as a towed
"crows nest" was never explored, something the Germans developed the Focke-Achgelis
Fa 330 rotary kite for. This was
a role the Rotachute would have
been well suited for.
The Rotachute was sidelined for the later Rotabuggy
project (see below). However after the war was over one of the
Rotachute prototypes was shipped to the USA for testing. The Americans
were very impressed with the results and looked into adapting the
technology for their own use. A decade later the Kaman helicopter
company was still looking into the use of the the Rotachute principal
supplies by air ( see
video at this link ).
How the Rotachute might have been used in service.
evolved Rotachute would need to
be towed all the way to the target (extremely slowly and with great
discomfort to the pilot) but it was suggested that aircraft could be
modified to carry a number of Rotachutes suspended from a bar. The
Rotachutes would then be suspended in turn at the end of the bar to
allow the rotors to spin up before being dropped. The painting above
imagines an A.W. Whitley modified for this purpose.
from the Whitley the Rotachutes
are guided towards their target.
In this case a river crossing, the classic target for such a pinpoint coup de main assault.
With gliders having proved themselves for the accurate delivery of
troops (The action to seize Pegasus
on D-Day being the prime example) Hafner looked at ways to use the
Rotachute technology to it's best advantage. British Horsa
were capable of carrying Jeeps but it occurred to Hafner that the Jeep
itself already had a set of wheels to act as an undercarriage and if
the Jeep could be mated with a rotor and tail it would
mini rotor-glider that could be landed with much greater accuracy and
into much more confined spaces than conventional gliders. It
would also be much cheaper than a conventional Horsa glider (it was
calculated that seven such Jeeps could be converted for the cost of one
Horsa Glider). A quick test of a Jeep (simply by dropping it from
increasing heights) showed that the basic suspension and structure was
more than adequate for the role. So in April 1942 was born the
"Rotabuggy" project. With the lessons learnt from the Rotachute initial
construction of the prototype proceeded very quickly. It featured an
extended windscreen and a large tail with tailplane and endplates. The
tail and overhead rotor could be quickly detached. The Rotabuggy was
flown from the front "passenger" seat with the controls hanging into
the Jeep from the overhead rotor. Some descriptions of the Rotabuggy
imply that it would only have flown with the one pilot on-board.
the Rotabuggy needed someone in both the "pilot" and "driver" position.
The "driver" used the conventional steering wheel to steer until the
craft was airborne, when the pilot took over.
prototype was ready to start towed tests behind a lorry in November
1943 but the lorry was not powerful enough to get it into the air. A
Bentley racing car had to be used to get it airborne, and then only for
short hops. A Whitley bomber was then used to tow it around the
airfield for longer hops (the Whitley itself stayed on the ground for
these tests). Problems with vibrations plagued the prototype and then a
heavy landing damaged the rotor blades and the project was delayed
while a new set were manufactured. It was not until September 11th 1944
that a first towed flight was attempted (towed by a Whitley) with Sqdn
Leader Little as the pilot and Flt Lt Packman (an engineering officer)
sitting alongside in the Jeeps"driver" position. The flight was a near
disaster, severe vibration occurred at the increased airspeed and the
Rotabuggy proved to be very tail-heavy in the air under tow and there
was no way to trim this out. After a very fraught flight with the
Whitley reducing speed to just above stalling the combination managed
to land safely. This was the Rotabuggys first and last proper flight
towed behind a flying aircraft. With D-Day past and the collapse of
Germany imminent and with a stockpile of Horsa gliders already built
there seemed little point in carrying on with the Rotabuggy project.
The prototype had its tail and rotor removed and was used by the
Airborne Forces Experimental Establishments motor pool at Beaulieu.
Ironically one of the tasks it carried out was towed tests of a
captured German Focke-Achgellis FA330 rotakite.
view of the Hafner Rotabuggy
The Hafner Rotabuggy
painted as if it had
gone into production and service
many online descriptions of the Rotabuggy it is
asserted that it was specifically nicknamed the "Blitz Buggy". This is
not true. The misunderstanding
results from a misreading of Philip Jarrett's "Nothing Ventured"
article in the October 1991 edition of Aeroplane monthly
magazine. "Blitz Buggy" was a nickname given to all Jeeps when they
were first introduced. The term was first used in American
talk" at the start of the 1940s to refer to any military vehicle. It
later became attached specifically to the Willys Truck 5 cwt 4x4 when
it was first introduced in large numbers. This nickname was itself
replaced by the term "Jeep".
to contemporary magazine article (Popular Mechanics Nov 1942) that
refers to Blitz Buggies.
Youtube video of US Training film "Crack that Tank" - 1 minute 15
seconds in hear reference to Blitz Buggies.
Hafner's last thoughts on the "rota" concept was the "Rotatank" . This
mated a heavy tank (a Vickers Valentine) with a huge tail and rotor.
The pilot would sit in the commanders hatch in the turret controlling
the craft in the air via controls descending from the rotor. A pair of
huge wheels on a "dolly" would be used on take off and then be dropped,
the tank landing on it's tracks. The scale of the project was daunting.
The rotor required would have been over 150 feet ( 46 metres) in
diameter and over 6 feet (2 metres) wide. It was calculated that no
existing single aircraft in RAF service could have towed such a design
and it was suggested that a Halifax 4 engined bomber would tow the
Rotatank but would in turn need itself to be towed by a DC3 Dakota to
get airborne. By the end of the war the Valentine was an out-moded tank
and had been replaced by even heavier designs. Not surprisingly the
Rotatank never got beyond the initial design stage.
view of a Rotatank complete
with the launch dolly with huge wheels. This would have been dropped
after take-off. The tank would land on its tracked running gear. Clutch
out of course!
Rotatank based on a Valentine
Mk X tank.
Afterwards and afterthoughts.
Raoul Hafner went on to head the helicopter division of the Bristol
Aeroplane Company, designing the Type
Belvedere helicopters. When
Bristol's helicopter division merged
with Westland helicopters in 1961 Hafner became Technical Director, a
post he held until retirement in 1970. He was killed in a sailing
accident in 1980.
A certain amount of criticism is levelled at the various "Rota"
projects, characterising them as hair brained "Heath
contraptions. There was something slightly amateurish and small-scale
about them to be sure, but that was largely the point, they were trying
to come up with simple, cheap, easily mass-produced solutions. Against
the rapidly changing background of the World War the extended
development and testing necessitated by a tiny budget, small staff
numbers and primitive facilities meant the projects never kept pace
with events. With hindsight it is clear the best use of Raoul Hafner's
genius and drive would have been to ask him to carry on with his navy
autogyro AR IV project, or combine his work with that of the G
Weir company who had the first proper British helicopter (The Weir W-5)
flying as early as 1938 and were working on the revolutionary W-9
and Nagler R2 Revoplan of 1932
Hafner AR III Gyroplane of 1935
of one of
the surviving original Rotachute prototypes at the Museum of Army
Flying , Middle Wallop.
Rotabuggy at the Museum of Army Flying, Middle Wallop
Rotabuggy article on the Aviastar website.
Notes on Sources
The two articles in the "Nothing Ventured" series by Philip
Jarrett in the August and
October 1991 editions of Aeroplane
Monthly magazine are highly recommended. The August Edition covers the
Rotachute and the September edition the Rotabuggy and Rotatank. Also
note that the October edition has a letter in the "Skywriters" column
by Ted Vaisey who worked on the Rotachute with comments on the earlier
A few paragraphs alongside a very good drawing of the Rotabuggy appear
in the Winter 2006 edition of Air-Britains "Aeromiltaria" magazine.
The Hafner Rotabuggy features in an article in the March 2012 edition
of "Britain at War" magazine and a letter from Alistair Mellor in the
May edition gives some details of the Rotatank design and a photo
showing that the Jeep section of the prototype Rotabuggy was used to
tow a captured Focke-Achgellis FA330 rotakite for trials.
B20 | Blackburn B40
Don | BP
P100 | Hawker Henley |
OA-1 | Vickers Venom
| Gregor FDB1