- WAS IT A GOOD IDEA?
By David Hobbs
The concept of producing a practical, winged, aircraft able to use
aerodynamic lift for flight, yet capable of Vertical Take Off and Landing
(VTOL) has fascinated designers since the dawn of powered flight. Whilst
helicopters have achieved it, their fixed wing cousins have not, to
anything like the same degree.
During World War II, the Germans produced a VTO (no 'L' because it did
not land) 'target defence interceptor' called the Bachem BA 349 'Natter'.
It was powered by a single Walter HWK 109 rocket motor augmented by
four boosters and launched vertically up a railed structure 80 feet
high. It had a rate of climb in excess of 35,000 feet per minute but
a powered endurance of only two minutes and was, in effect, a 'manned
missile' intended to intercept daylight bombing raids. It was armed
with 33 Type R4M unguided rocket projectiles in the nose and, as soon
as he had fired them, the pilot ejected himself and the rocket motor
for parachute descents while the remaining wooden airframe structure
crashed to the ground. Ten were deployed to Kircheim-on-Teck in April
1945 but the war ended before they could be used operationally.
The "Natter" was a weapon of desperation but, no doubt stimulated by
it, the Admiralty wrote a more rational specification in 1945 for a
"quick reaction" fighter capable of countering Kamikaze aircraft. The
Fairey Aviation Company sketched a design for a small, turbojet powered,
delta winged 'tail sitter' that achieved VTO by being boosted up rails
fixed to a carrier's flight deck. It would have landed 'more or less'
conventionally. The end of the war against Japan took the urgency out
of the requirement but it continued as a post war research project with
some interest from the RN and RAF. A number of scale models were launched
vertically from a rail structure at WRE Woomera. There was some USN
interest in turbo-prop powered 'tail sitters' in the USA at the same
time but these, too, came to nothing and the concept proved to be a
High speed research studies carried out at the Royal Aircraft Establishment,
Farnborough, in the late 1940s led scientists to predict that future
supersonic aircraft would need wings so small that conventional take
off and landing on flight decks would not be possible. Thus, they believed
VTOL would be inevitable for future generations of fast jets because
there was no other way of operating them. The concept had nothing to
do with simplified deck operations or improving rough sea landing capability.
By 1954, the Admiralty's Construction Department had prepared plans
for a light fleet carrier capable of operating the new Supermarine N113
(Scimitar) fighter in the short term but suitable for the operation
of VTOL aircraft in the mid 1960s. The design was unfettered with conflicting
requirements and, although not perfect, had greater aircraft operating
potential than the Invincible class designed 15 years later. The same
department produced sketch proposals for modifications to the Majestic
class that would have enabled MELBOURNE and SYDNEY to operate the same
Ashore, NATO became interested in VTOL strike fighters. This followed
a large and expensive programme of airfield construction in Europe intended
to enable tactical aircraft to support NATO armies against any Soviet
aggression. Despite the evidence from two world wars and Korea that
airfields are extremely difficult to destroy, a belief grew that the
new concrete runways and hard-standings were vulnerable to attack and
that aircraft should be dispersed "into the field". The Treaty Organisation
was trying to standardise a number of weapons and systems at the time,
ranging from rifles and their ammunition to radars. In consequence two
relevant NATO Basic Military Requirements (NBMR) were written. NBMR
3 called for a lightweight, single-role, VTOL strike aircraft capable
of carrying a single nuclear weapon on a short-range tactical mission.
It had to be able to take off and land vertically on unprepared fields
near the Forward Edge of the Battle Area (FEBA). NBMR 4 asked
RN F/A 2 Sea Harrier. The Sea Harrier of today is a different
beast from its Falklands War days. The aircraft employs a very
sophisticated air-search radar, the 'Blue-Vixen', and AMRAAMs
(Advanced Medium Range Air-Air Missiles) for long range air superiority
tasks and was until very recently, considered the best air superiority
fighter in Europe. (RN)
a VTOL tactical transport aircraft in the C 130 class able to support
NBMR 3 in the field. Both completely under-estimated the logistic problems
posed by dispersed operations and took no account of bad weather recovery,
homing through hostile or friendly airspace, intelligence briefing,
site defence and many other practical details.
Britain, France, the USA and Germany all put effort into NBMR 3 but
only Britain put design effort into NBMR 4. Aircraft such as the Hawker
P1127, Dassault Mirage IIIV and VAK 191 were all flown for evaluation
purposes with paper studies based on them put up for the glittering
prize of standardised NATO production. The British Treasury hoped that
production by an international consortium would radically reduce development
costs for a new UK aircraft but NATO had no power to order anything
itself and could only recommend a solution. Sensitive to the political
issues at stake, it named the British and French entries as "joint technical
winners" and left the various governments to make of that what they
In 1961, the British concept had evolved into a practical strike fighter
design which was given the Hawker type number 1154. It was more capable
than the NBMR had demanded and was to have a single Bristol Siddeley
BS 100 engine, developed from the Pegasus, with rotating nozzles giving
a far more elegant solution to the VTOL problem than the batteries of
lift and thrust jets fitted in the rival designs. It could certainly
land vertically and with a form of reheat' known as "plenum chamber
burning"; it was capable of VTO with a small military load for a few
minutes endurance. It did much better with a short take off run, however,
and was better referred to as a Vertical/Short Take off and Landing
(V/STOL) aircraft. It would have been expensive to develop and operate
but it would have been supersonic at height and would have offered a
useful performance increase over aircraft like the Hunter and Scimitar.
With an engine optimised to give a thrust to weight (T/W) ratio of better
than 1:1 on landing, however, it would have had a poor Specific Fuel
Consumption (sfc) in cruising flight. This would have led to a payload/
radius of action capability inferior to that of other contemporary fighters,
especially those designed in the USA. Export potential would not have
been great, as it would have been expensive and very specialised. Sir
Sydney Camm, Hawker's chief designer, is believed to have said that
V/STOL fighters would not sell well until they approached the capability
of the F-4 Phantom. Time has shown him to be right.
To complicate matters, in 1961 the UK Defence Secretary insisted that
the P1154 form the basis of a joint project to replace the de Havilland
Sea Vixen in RN service and the Hawker Hunter in RAF service. This despite
the fact that the former wanted a two seat, twin-engine, high flying
fighter with a very powerful radar forming the core of an integrated
weapons system and the latter a single seat, single-engine, low flying
ground attack aircraft without radar. Further, the naval version had
to be stressed for catapulting, carry a large fuel load to give endurance
on combat air patrol (CAP) and weapons for at least two interceptions.
The RAF version could accept less fuel and lighter structure to give
"quick dash" strike capability. Two years were wasted trying to produce
a common airframe that met these two very different requirements before
the RN managed to convince the British Government that the USN Phantom
II was the only aircraft capable of delivering the operational capability
that it required. Eighteen months later the simplified RAF version was,
in turn, cancelled in favour of a buy of Phantoms. The NBMR 4 design,
by then identified as the Armstrong Whitworth Type 681 was also cancelled.
Some operational analysis of V/STOL operations was carried out in 1965
using nine aircraft derived from the P1127 and given the name Kestrel.
Three each were purchased by the Governments of the UK, USA and Germany
to form a Tripartite Evaluation Squadron, which operated from RAF West
Raynham. Pilots and ground crews were drawn from the RAF, USAF, Luftwaffe
and US Navy. The RN was not represented. When the squadron disbanded,
six of the eight surviving aircraft went to the USA for further evaluation
while two continued with development work in the UK. The Luftwaffe and
USAF both concluded that operations from hardened aircraft shelters
on conventional airfields by conventional aircraft were both cheaper
and more efficient than dispersed operations by VTOL aircraft. Had there
been operational merit in the latter, it is difficult not to believe
that the USAF would have hastened it into service in the Vietnam War.
After all the investment, some interest in V/STOL remained in the UK
and a developed version of the Kestrel went into operational service
with the RAF in 1969. This had little to do with cost-effective delivery
of an interdiction/strike capability and more to do with the sitting
Labour Government's wish to provide some work for the British aviation
industry which had suffered a series of cancelled projects in the preceding
months. The new version was given the name Harrier, originally intended
for the P1154 had it gone into service. 84 were ordered in the first
batch but, significantly, the RAF ordered 200 of the cheaper but more
capable Jaguar strike aircraft to form the main component of its strike
In retrospect, this British fascination with the platform, rather than
the operational effect it was intended to create is difficult to understand.
It contrasts starkly with the German decision to focus on a strike capability
that was best provided by conventional aircraft operating from conventional
airfields. Even more difficult to understand is the NATO planners' assumption
that concrete runways were the vulnerable part of the equation, not
the aircraft or their logistic and technical support. On the ground,
near the FEBA, aircraft and the hundreds of men and vehicles needed
to make them work would have been vulnerable to small arms, mortar and
artillery fire in addition to missile and air attack. In hardened shelters
on an airfield in a rear area, they must have been less so, even though
it took longer to reach an urgent target. The concept of dispersal away
from airfields was quietly dropped in the 1970s.
The US Marine Corps was impressed by the Harrier's undoubted ability
to deliver bombs in amphibious operations and to move ashore with the
marines and their helicopters. I believe they were also impressed by
the fact that it was so highly specialised in the short-range ground
attack role that it was not likely to be miss-employed on naval missions
as the F-8 Crusader and F-4 Phantom often were. The politics behind
procurement can be surprisingly devious. Despite a licence agreement
between Hawker Siddeley and McDonnell Douglas the AV-8A Harrier was
built in such small batches that all were built in the UK.
After the cancellation of its CVA-01 carrier project, the RN found considerable
political opposition to the idea of maintaining any sort of fighter
aircraft in ships at sea. The Chief of Naval Staff, Admiral Sir Varyl
Begg was an opponent of embarked aviation and acted quickly to run down
the conventional carrier force. He focused attention on a future navy
comprising cruisers armed with missiles and, to a limited extent, VTOL
aircraft or helicopters. Design work started on a command cruiser which
went through more than 50 iterations and which had an aviation facility
which grew from a single spot for a helicopter aft to a runway running
the length of the ship with an island structure to starboard. The latter
proved so superior, even for the operation of a modest number of helicopters
that it was adopted. The ability to embark Harriers was obvious and,
from the outset, was a factor in the design of what became the Invincible
There is a myth that V/STOL fighters can use small, simple and, therefore
cheap, ships, often called Harrier Carriers, which provide affordable
capability. In researching background papers for this article, I found
a Paper written in 1966, only six weeks after the cancellation of CVA-01,
which puts the counter argument. It compares a baseline V/STOL aircraft,
the Kestrel, with the maritime Jaguar, in development at the time for
the French Navy and seeks to put numerical values on their relative
cost effectiveness. Kestrels were more expensive to buy than Jaguars
in the ratio 8:5. Because the latter was designed for cruise efficiency
in flight and the former for its take off and landing performance, Jaguars
have better SFC and carry more weapons further, faster. For a given
task, fewer Jaguars than Kestrels would be needed.
The Paper compares two weapon effort planning scenarios, sinking a destroyer
sized contact and destroying a bridge. Different parameters were used,
some favouring the Kestrel, some the Jaguar. On average, it was evaluated
that 12 Kestrels would be needed to do the same task as 8 Jaguars and
there are tasks that the latter could do that the former could not.
Thus cost factors of 96 against 40 were given making the Jaguar more
than twice as cost effective as the Kestrel. The larger number of Kestrels
need a large ship from which to operate but it would be a simple V/STOL
carrier. There is, therefore, a cost penalty of building the V/STOL
capability into every aircraft rather than the single ship from which
they operate. Taking the CTOL (Controlled Take Off and Landing) comparison
further, the Paper examines the cost of putting V/STOL capability back
into the carrier. It uses prices equivalent to half the cost of a Jaguar
for each catapult and the cost of a whole Jaguar for the arrester wire
system. For a Hermes sized ship with two catapults and arrester wires,
this modified the cost factors to 96 against 50. It is still nearly
twice as expensive to procure the less capable V/STOL aircraft and the
'cheap ship' has been 'bought' by expenditure on an expensive but less
capable aircraft. The numbers may vary, but these factors still hold
good for today's Joint Strike Fighter where comparisons show that the
USN's carrier version is cheaper but goes further with more weapons
than the V/STOL version. It is arguable that the British decision to
take V/STOL to sea was politically rather than capability based.
Sea Harriers began to enter front line service with the RN in 1980.
Although not as capable as conventional carrier aircraft, it was immediately
apparent that they were more effective in their mobile base than the
discredited dispersed operations had been ashore. The new aircraft's
Release to Service was limited at first by the novelty of its deck operations
and weapons systems. It was still being expanded five years later. In
addition to INVINCIBLE, the former CVA HERMES was modified to operate
Sea Harriers from 1981 onwards.
Fighters embarked in these two ships were fundamental to the British
plans to liberate the Falkland Islands after their seizure by Argentinean
forces in 1982. 28 out of RN's total, at the time, of 32 Sea Harriers
were deployed in four Naval Air Squadrons, one of which was formed at
short notice. They flew 2,000 operational sorties and achieved 32 confirmed
kills of enemy aircraft in air to air engagements. They also carried
out successful strikes against enemy shipping and shore targets. None
were lost in air combat but two were lost to ground fire and others
in operational accidents. An overall serviceability rate in excess of
90% was achieved.
This performance surprised many outside the RN and was sufficient to
prevent Argentine air forces from defeating the amphibious landings.
However, by comparison with the air defence system the Service had wanted
but lost with the cancellation of the CVA-01 replacement carrier project,
the performance fell short of the optimum. Enemy aircraft and missiles
were able to penetrate the defences and inflict heavy casualties in
ships and lives. This was predictable due to the lack of embarked Airborne
Early Warning (AEW) aircraft and shortcomings in Sea Harrier performance
and armament. With only a basic pulse radar, no Beyond Visual Range
(BVR) weapon, no high speed dash to gain position and no embarked tanker
aircraft to sustain them on CAP (Combat Air Patrol) or give flexibility
in recovery, the Sea Harrier was markedly inferior to the aircraft it
It did well because of the highly skilled pilots available from previous
conventional carrier operations, many of which were instructors with
thousands of flying hours. It also had a very good weapon in the newly
supplied American AIM-9L Sidewinder and an excellent landing capability
in high sea states that caused excessive ship motion. Although rated
as a Fighter/Reconnaissance/Strike aircraft, the FRS-1 Sea Harrier could
hardly be compared with USN carrier aircraft in the last two roles and
relied on above average pilot skill in the first to command success.
In 1982 that level of skill was available.
Given this very public success, hopes for export sales rose and several
navies bought Sea Harrier or AV-8 derivatives but only in small numbers.
They include India (23 plus 4 trainers); Spain (32 plus 3 trainers);
Italy (16 plus 2 trainers) and Thailand (7 plus 2 trainers purchased
from Spain second hand). Total P1127/Harrier/Sea Harrier/AV 8 production
has amounted to 15 prototypes, 237 first generation single seaters,
98 Sea Harriers, 395 AV 8B second generation single seaters and 86 trainers
of all versions.
By the 1990s, the Sea Harrier FRS-1's capability as a fighter was becoming
marginal and replacement with the F/A-2 was timely. This has the Blue
Vixen pulse doppler radar, track-while-scan capability and up to four
AMRAAM missiles constituting one of the West's best fire control systems,
albeit fitted in a 40 year old airframe design. Even with this upgrade,
it faces tough opposition in many areas of potential conflict. The 'A'
indicates a limited attack capability giving this improved version a
limited swing performance.
Given this background, we have to answer several key questions before
deciding whether V/STOL was a good idea for the RN;
Q: Was V/STOL inevitable?
A: Advances in wing design made it possible to produce very successful
fast jets that could land on carriers conventionally. The RAE scientists
were wrong; it was not, therefore, inevitable.
Q: Was V/STOL ever viable for the USN?
A: The USN considered and rejected it. It did not accept the reduction
in operational capability that V/STOL brought with it. Even today, the
USN will not accept the V/STOL version of the Joint Strike Fighter,
which is being considered for the USMC.
Q: Why did the USMC opt for it?
A: It wanted a specific aircraft to support amphibious landings, moving
ashore with the marines. Almost as important, it wanted one that could
not be used for general fighter duties by the USN in a carrier battle
Q: Was it the best fighter that the RN could buy?
A: No, but it was the only aircraft that the British Government of the
day, which cared little for cost effectiveness or capability issues,
would allow it to buy. In practical terms, it was the only fighter that
could be operated at sea once the mistake had been made of ordering
ships of such limited capability as the Invincible class. In naval terms
it was not the best fighter, nor was it the best that could be operated
from a ship of the size the RN had planned to procure.
Q: Did it perform as expected?
A: It performed better than expected in the Falklands War but desperately
needed the capability upgrades in the F/A-2 version.
Q: Could anything else have done better?
A: An embarked AEW capability would have made the most significant difference
in the Falklands War. A USN fighter operated from a larger ship would
have been a better platform.
Q: Is another V/STOL fighter a viable replacement for the Sea Harrier?
A: Look at the JSF. V/STOL versions lack the radius of action and weapon
carrying options of the CTOL versions and cannot guarantee to land on
vertically with unexpended ordnance in the hot summer temperatures found
in the Gulf. They are more expensive to buy and maintain and offer less
operational capability. Even today, 41 years after NBMR 3, CTOL remains
the more cost-effective option.
We must conclude from these answers that V/STOL was seen as a good idea
politically and provided something for the work force to build after
the spate of cancellations in the mid 1960s. In the negative climate
of opinion that surrounded naval aviation in the 1970s, it was the only
fighter option available to the RN and no Government wanted to listen
to well reasoned arguments about cost, capability or effectiveness.
In naval terms, it was not the best fighter available, nor did it represent
the most affordable weapons system. The Service was fortunate to have
the skill base to make it work and to 'fight above its weight' in the
Falklands War. The ability of Sea Harriers to recover in rough weather
was fortuitous since it had not been called for in the Staff Requirement.
Comparisons with ARK ROYAL were inappropriate, since she was at the
end of a very long capability stretch since her original completion
and had, in any case, been scrapped. The new generation of carriers
the RN had tried to procure, the CVA-01 class, were specifically designed
to be good at operating CTOL aircraft in rough weather with an eye to
possible strike operations in the Barents Sea. The true comparison should
be made with them.
With the introduction of simple carriers and their limited V/STOL air
groups, the RN not only lost the ability to operate affordable AEW aircraft
but also the capability to cross deck strike aircraft with its biggest
and most important ally, the United States Navy. Worse, the change of
direction made it impossible to purchase or make use of USN carrier
aircraft types, forcing the RN down the lonely and expensive route of
having to develop its own unusual and expensive fighter with few prospects
of export sales. The USN had itself evaluated the idea of a Sea Control
Ship with a mix of V/STOL fighters and helicopters embarked but had
rejected it as being too expensive for the minimal capability provided!
They cannot have been impressed by the loss of allied capability as
the RN chose to follow this expensive option. The adoption of the CV
version of the Joint Strike Fighter by the RN would reverse this situation
and bring the Service back into line with its principal partner.
In historical terms, V/STOL was made to work and produced better results
than the UK Government had a right to expect. Other aircraft and air
defence systems would have performed better at a more competitive procurement
cost had a more enlightened outlook prevailed in Whitehall. In terms
of cost effective capability, V/STOL was not a good idea. A combination
of F-4 Phantoms and Gannets was so nearly achievable and would have
been better. A replacement combination of F-14 Tomcats and E-2C Hawkeyes
could have gone into service in the 1980s and would still be very hard
to beat even today.
Postscript May 02:
Those who opposed the procurement of a V/STOL fighter for the Royal
Navy in the 1960s and 70s feared that weight growth, common to all previous
carrier fighters in service, would eventually prevent the aircraft from
flying. Their time-scale was out but they were right. The principal
reason for the Sea Harrier's early withdrawal from service in 2006 its
lack of power from its early Pegasus engine. Fitting the Pegasus 107
engine into an airframe designed over 40 years ago would be technically
complex and the cost of modifying 30 airframes was unofficially believed
to exceed AUS$500 million. There is a lesson here that no matter how
good the weapon system, a fighter that relies on vertical landing performance
will always need engine development if it is to continue to fly as weight
grows during its service career. Let us hope that the lesson is learned
before the decision on which type of JSF to order is taken.