Advanced Airship Corporation (AAC)
It was in early 1972 that
a company by the name, Mercantile Airship Transportation Limited
( MAST ) formed for the development of large rigid airships. Major
M.W. Wren was the Managing Director. In
1978: Thermoskyships Limited ( TSL ) formed in the Isle of Man
and acquired MAST in early 1979. Major M.W. Wren was the Chairman
and Chief Executive. As a Public Limited Company it raised £2.4
million on the London Stock Exchange towards the development of
an unconventional rigid airship.
The company had been looking
at a series of design concepts, one being the design concept of
lenticular airship design (dubbed flying saucers) which included
the proposal of using heating of the lifting gas to control buoyancy.
The idea that there was a place for airships to fulfill a transportation
gap between fast jet air transport, and slower sea transportation.
It was then that Malcolm Wren and Roger Munk, realised the value
in joining forces, as Munks Airship Developments had already proved
the concept of smaller airships with the AD 500. The resulting
merger of took place a year later on 29th May 1980, with Thermo
Skyships purchasing the company for £1 million. The merger
saw the prospect of putting both a large rigid and a smaller non
rigid design airship in to production.
The resulting merger, in
July 1980, Thermo Skyships name was changed to Airship Industries
Ltd.(AI). During the approximately two-and-a-half years the Thermo-Skyships
team spent at AI, it proposed several abortive designs, for non-lenticular
rigid airships. Much money had already been put in to the Thermo
Skyship company and it had grown to a 30 strong design team. The
idea being that the non-rigids AI designed ships would provide
an income to build the larger and now ellipse shaped 100 seat
passenger ferry airship for intercity use. However it soon became
clear that the two airship projects could not share the same design
lines and concepts.
A de-merger from Airship
Industries in the 1982 saw the split away from the group of a
smaller company headed up by Major Malcolm Wren, and the creation
of Wren Skyships Ltd. the reason for this was due to the different
design approaches for airships undertaken by both organisations
and the structural design question of airships. Wren Skyships
Limited was formed from key members of the rigid division of AIL
and began operating with Major M.W. Wren as Chairman and Chief
Executive, P.W.C. Monk as Technical Director and J.A. Dean as
Chief Accountant. It took over the Isle of Man premises of AIL
and had two subsidiary companies :-
a) American Skyship Industries Inc., formed in July 1982 and based
at Lansdowne Airport, Ohio.
b) New Zealand Airships Limited
Original project ideas from
the company, such are the R.30, which was a 1.1 million cubic
feet airship, as a design response to the US Coastguard requirements
during the U.S. President Jimmy Carter administration. The hull
would be of aluminum alloy,Alelad 2024-T3 with a thickness range
of .010 to .025 in. Supported by 24 longitudinal and 14 ring frames
two of which would be heavy duty to support engines and loads.
It would not have individual gas cell, the metal hull covering
being itself the gas container for simplicity and weight saving.
On operating and flight costs,
the R.30 as a cargo carrier was claimed to be superior to a Boeing
737 aeroplane for ranges up to 600-700 miles, while an early 1980's
study of a passenger version between Paris and London city centres
at 45 minute intervals using (using 6 airships), showed taking
30% of the existing traffic and making 40% profit after allowing
£10m each for the two city centre terminals.
Studies were also made of
the R.30 in a naval role, usually regarded as a non-rigid reserve.
The view that non-rigids are cheaper to produce than rigids and
were starting to prove themselves at the time. Another advantage
of a non-rigid airship was that they could be manufactured and
assembled in different places removing a possible constraint of
the need for hangar space. The idea of a "metalclad"
airship was to improve on the concepts gained by by the US Navy
with their non rigid experience.
The Chief Designer, Mr Pat Monk, (not to be confused with Roger
Munk of Airship Industries) joined the company in 1980 from New
Zealand Aerospace, and the Wren Skyships Design team, engaged
in designing a sophisticated, metal clad airship, the RS.1.
In 1982, the R.30 concept
was later redesigned as the RS.1 and was to be 420ft long with
a maximum diameter of 83.25 feet. Two balloonets would give it
a pressure height of 5,000 ft, and hold a 1,592,000 cubic ft of
gas. The RS.1 would be powered by 4 Airesearch TPE 331-15 turboprops.
The design speed at flying at 5,00ft would be 149.3 mph, or at
sea level cruising with 3 of the 4 engines at 121 mph.
At the time the RS.1 was
designed as much larger than the Airship Industries Skyship 600,
it's contemporary non rigid ship, and similar in concept to the
successful US Navy type ZMC2. In 1987, the concept RS.1 proposed
as a 25 tonne payload ship for surveillance, search and rescue,resource
development and relief work. This was later as dropped and the
company moved to a smaller non rigid design of ship, the ANR 1.
becomes Advanced Airship Corporation (AAC)
At a board meeting on 16th
September 1987, Major Malcolm Wren stepped down as executive chairman
from the board due to health issues, and Brigadier John Hooper
was appointed to as Chief Executive of the company. In 1987, Wren
Skyships Limited was then reorganised and became the Advanced
Airship Corporation (AAC) which was formally incorporated in February
The new company, AAC based
themselves on the Isle of Man, with the understanding that a cost
effective link between the UK at Liverpool and the Isle of Man,
could be used. Traditionally the island was serviced by small
regional airlines, and the Isle of Man Steam Packet Ferry Company,
operating a ferry service, to connect Dublin and Liverpool. Wren
Skyships undertook a feasibility study and knew there was a market
to ferry workers to and from the Island, from both the United
Kingdom and Ireland. From company documentation it was quoted
Isle of Man makes an idea operating base for the initial routes
under consideration. Since these will be new routes e.g. Jurby
to Preston, route allocation will not present a significant problem".
The concept of the ANR was to fill the role to be a competitive
passenger transport on routes up to 80 nautical miles. The concept
design was to fill the role and take on airship operations beyond
the tourist flight sector which had been established by Airship
Industries operations using the Skyship 500 and 600 models, and
in to a a regular point to point passenger service. To this end
the ANR was designed with a maximum speed of 95 mph compared to
a Skyship 500's maximum speed of 67 mph. The ANR was designed
to be a comparative passenger transport aircraft over short ranges.
ANR 1 Design
Construction of the prototype ANR 1 was commenced. The ANR 1 was
a smaller ship design, and AAC obtained enough funding to commence
the project. Attention to streamlining was a focus of the design
team of Murray McGregor as Chief Designer followed by Bruce Blake.,
with the intention to make it faster than existing airship concepts.
Three new design features which stood out were:
- balloonets at the extremes of the ship,
- retractable handling lines.
- balloonets in the extreme bow and tail of the ship were to save
around 30% of fabric weight, in comparison to contemporary non
rigid designs. Another idea of having he balloonets at the extreme
ends of the envelope, would also improve control of the airship's
trim, along with giving a higher pressure to the envelope at the
nose and tail.
For streamlining the mooring cables were to be designed to be
drawn back against the hull in flight, and the mooring battens
common in other non rigid airships were dispensed with, in favor
of a composite carapace.
For ground clearance at take off, the tailfins were placed in
an X configuration.Twin Allison 250 - B17C turboprops, each of
420hp totaled some 840h.p. As turbines are heavier on fuel than
piston engines, priority was for high speeds by airship standards
over short ranges, rather than long endurance. The weight of the
gear to retract handling lines in flight would be offset by the
turbines' lower weight per horse power than piston engines.
The ANR 1 Allison engines
were attached via a 25.42ft (7.75m) stub wing, which also contained
the 1,272 litre fuel tank, attached at the rear of the gondola,
which has a 8 ft 3 bladed propeller and engine at each wing tip,
and can be rotated for 75 degrees to 30 degrees down. The deflection
of the slipstream may be increased to 90 degrees by the deflection
of a single trailing edge flap.
To help with control the ANR was planned with both bow and stern
thrusters. These were low velocity cold air jets which could be
vectored to provide pitch and/or yawing moments and vertical an/or
sideways forces. The low velocity jet produced a minimum thrust
of 27gh. Ballonet air was designed to be used as the supply reservoir
boosted by two fans. The air passed to the pllenum chamber and
thence to one pitch and two yaw ducts. With the fans running stalled,
thrust is immediately available when a duct valve is opened. This
system was designed to assist control at low airspeed, less than
10 knots, and during a hover. Such
a system avoids the complication of placing a fan at the thruster
which could be difficult mechanically.
The construction of the new shed was commenced at the old RAF
Jurby airfield on the northern tip of the Isle of Man, began
on 14th March 1988, and erected in a period of almost of 4 months
to the day, when the first ceremonial "sod cutting"
day, the shed was completed, and officially opened on 14th June
Construction of the ANR 1 was undertaken in the newly completed
shed. In August of 1988, Airborne Industries, the airship and
balloon manufacturer delivered the envelope from their Leigh on
Sea fabric manufacturing site. By December 1988, the prototype
envelope was ready for air inflation tests. The construction of
the gondola, engines and tailfins commenced over 1989 and into
Hangar Storm Damage
It was during a gale force
storm on Friday 13th January, 1989, the main fabric door on the
hangar torn, and eventually destroyed. The envelope was quickly
deflated in order to safeguard the airship. Temporary scaffolding
and covering was erected to protect the interior of the hangar.
Two months after the storm, on 13th March, the envelope was re-inflated
inside the hangar.
Further research and design continued on the prototype ship. In
August 1989, a rupture occurred in the original nylon envelope
which had been air inflated some 22 months. The tear was repaired
and the envelope re-inflated in September 1989. By November 1989,
it was decided that a new a stronger Kavlar PU type material,
known as Aramid, could be used for the envelope. The envelope
would be lighter, stronger and less permeable to helium gas. Due
to it's design, would not allow the envelope to stretch change
shape, and therefore designed to be similar to that of a metal
clad airship such as the US Navy ZMC2, and the original R30 metalclad
design ship. The design team was presented with a difficult choice,
to continue with and fit the existing development envelope to
the prototype ship, and then replace it with the newer envelope
when it was available, or to wait, and fit the new envelope when
it was ready.
There were concerns over the serviceability of the existing development
fabric for high speed flying, even though the existing enveloped
more than adequately fulfilled the FAA requirements for tear strength.
It was the company's intention to use the first envelope for early
low speed test flying and then replace it with the newer envelope
during the test flight programme. However the new kevlar fabric
would be made available sooner than originally planned. After
a pressure tear test on 5th April 1990 on the existing nylon envelope,
a rupture occurred outside of the the test area, it was decided
that the new aramid envelope was required. Investigation in to
the envelope self deflation, no cause could be attributed to it.
With the new envelope, it was seen than an envelope change would
take 2-3 months, and ultimately impose a delay on the production
of the ANR No.2 prototype ship.
The new envelope was delivered
and the prototype ship gondola and tailfins carefully rigged and
attached to it.This added addition time to the construction of
the ship, and delayed the ANR 1 further final completion. Due
to the weight of the envelope, it was hung from the shed roof
and air inflated to keep shape.
Moving in to the new decade,
by August 1990 saw the avionics, fuel systems and main pilot controls
being manufactured and assembled the work had commenced with the
ribs for the gondola already being fitted to the gondola jig.
The design team expanded and the company took on additional office
space at the airfield next to the hangar.
With an oil price shock,
the ending of the Cold War, and the considerable drop in defense
spending, added to that spiraling inflation rates for many countries,
the world was plunged in to a deep financial recession. The impact
it had on the UK economy was not felt until the winter of 1990
and so plunging the country in to recession in the beginning of
1991. AAC was hampered by liquidity funding problems, and a withdrawal
of funding from the Middle East sources. Work on the ship finally
stalled, and in June 1991 the work on the ship, ceased, and 90
of the 120 the staff at the company were made redundant. The remaining
staff were kept on to keep a care and maintenance position for
the ship and the assets along with key members of the design team.
The helium stocks, of excess of 250,000cft were returned to their
suppliers to avoid hire charges on the helium bottles.
Alternative funding was vigorously sought by the board of Directors
over the next 18 months, By early 1993 funding options were no
longer available, and unfortunately Advanced Airship Corporation
went into liquidation on 1st March 1993. By 27th April 1993, the
ANR 1 airship gondola and envelope was sold, to Lindstrand Balloons,
at Oswestry and delivered to their premises. The gondola was later
again transported to Aviodrome,
Lelystad airport in
the Netherlands. Receivers sold the property owned by the company
on 27th September 1993, and the shed later dismantled.
The same financial recession and liquidation problems also saw
the closure of Airship Industries, in September 1990, the same
company which AAC had merged from.
The Jurby hangar remained
in place late in to 2009, when it eventually demolished.
If you want to see part of
this unique peice of aviation history built on the Isle of Man,
today the a segment of the composite nose carapace, one fin structure
and one ruddervator, can be seen on show at the Isle
of Man Motor Museum. The Museum is located on the same Jurby
Airfield where the AAC were based. Sadly
today, all that remains of the hangar at Jurby is the low outer
wall, within which is the service area and parking for the nearby
Hybrid Aircraft - Patroller 3
The chief designer, Bruce Blake went
on to form Advanced Hybrid Aircraft (AHA). The Advanced Hybrid
Aircraft team has prepared the design of a new and affordable
hybrid aircraft named Patroller 3, or simply P3. This aircraft
can fly low and slow, or alternatively can dash at higher airspeed
and higher altitude in pursuit of a land or sea target. The purchase
and maintenance costs are affordable, whilst the operating costs
will be much less than those of current manned aircraft and rotorcraft.
The energy-saving P3 can loiter at low power for as many as three
days approximately 70 hours, over a site of interest (bay, border
crossing, sea-lane). At cruise power setting, on three engines,
the endurance of 30 hours is suitable for quickly scanning a border
The P3 is helium filled (similar to an airship) and it derives
75% of its lift from the buoyancy of the helium (aerostatic lift).
The remaining 25% of lift (100% total) is derived from the wing
and the airframe-lift (aerodynamic lift of hull and stabilisers).
Thus the Take-off weight may exceed the aerostatic lift by 33%
The AHA team have already
had scale prototype for testing purposes. The design configuration
has been flight tested using a 40% scale R/C prototype. The main
aim was to prove that both Take-off and Landing (and taxiing)
may be accomplished on the airfield with NO groundcrew, simply
under the control of the Pilot. Historically, small non rigid
airships or "blimps" require a groundcrew of 10-15 strong
More details on the new airship
project and Patroller airship can be found here
Special thanks to Terry Turner,
Bruce Blake and Alastair Reid for source reference material referenced
for this page.