Table Of ContentCOMBAT 132
AIRCRAFT
Peter E Davies
F-102 DELTA
DAGGER UNITS
132
F‑102 DELTA DAGGER UNITS
SERIES EDITOR TONY HOLMES
132
Peter E Davies
F‑102 DELTA DAGGER
UNITS
C O N T E N T S
CHAPTER ONE
A NEW SHAPE 6
CHAPTER TWO
DRAWING DAGGERS 13
CHAPTER THREE
DEFINITIVE DAGGER 28
CHAPTER FOUR
CAGING THE ‘BEAR’ 51
CHAPTER FIVE
ON GUARD WITH PACAF 66
CHAPTER SIX
ON GUARD AT HOME AND AWAY 77
CHAPTER SEVEN
LATTER DAYS 86
APPENDICES 92
COLOUR PLATES COMMENTARY 92
INDEX 96
6 CHAPTER ONE A NEw ShAPE
ChAPTER ONE
A NEW SHAPE
For some aircraft manufacturers, certain structural features became A replica of the ramjet‑powered, delta wing
Lippisch P.13a, displayed at the Military
their design signatures. For example, the Hawker or de Havilland
Aviation Museum in Virginia Beach, Virginia.
vertical tails in the 1930s, Northrop’s 1940s flying wings and The pilot’s cockpit was located in the thick
Boeing’s podded engines in the 1950s. For Convair, its delta wing was vertical stabiliser and the coal‑burning
‘powerplant’ was suspended behind the
such a distinctive feature of many of its post‑war designs that the company
nose air intake. The aircraft, which never
considered trying to patent the idea. It enabled the manufacturer to develop advanced beyond the design stage, was
interceptors that served widely in USAF and Air National Guard (ANG) intended to be a cannon‑armed interceptor
for Luftwaffe Defence of the Reich fighter
units for more than 30 years, create a prototype supersonic seaplane fighter
units charged with halting the USAAF and
for the US Navy (in the form of the YF2Y‑1) and build the world’s first RAF heavy bomber armadas that steadily
supersonic bomber for Strategic Air Command (B‑58 Hustler). destroyed the country’s infrastructure in
round‑the‑clock raids from late
In the early 1940s Robert T Jones, an aerodynamicist at the National
1943 onwards (Wiki Commons/
Advisory Committee for Aeronautics (NACA), recommended a thin delta Zackcbowen)
wing for high‑speed flight based on his research data which explored drag
statistics and the sweep angles for this type of wing, with a rounded leading
edge. However, some scientists doubted that delta wings would behave
well at lower speeds, particularly for landing when no clear stall point
would be indicated to the pilot. Others felt that controlling the wing’s
tendency to generate high roll rates in conditions of high lift would prove
too challenging.
In 1945, when it became clear that German designers had moved well
beyond such theoretical work, NACA technicians were able to study a
captured German Lippisch DM‑1 wooden glider – the first pure delta
CHAPTER ONE A NEw ShAPE 7
wing aircraft. Its thick wing spanned 19 ft 8 in, with a leading edge sweep
of 60 degrees. A disproportionately tall vertical tail which included the
pilot’s canopy extended along most of the 20 ft 9 in fuselage. Dr Alexander
Lippisch’s Delta 1 glider had flown in 1930, followed by a powered version
with a 30 hp Bristol Cherub engine and the DFS 194 rocket‑powered delta
which, in 1937, became the ‘Projekt X’ progenitor of the Messerschmitt
Me 163 rocket‑powered interceptor.
By 1945 Lippisch, who was born in 1894 and served as an aerial
photographer in World War 1, had already moved on to experiment with
improved projects based on the DM‑1. These included the ramjet‑ or
rocket‑powered P.13a and P.14 that were intended to reach speeds in excess
of Mach 1.80. The scarcity of oil‑based fuels in Germany towards the end
of World War 2 forced designers to use a coal‑burning ramjet engine with
rocket boosters for the P.13a concept. The rockets would have accelerated
the aircraft to 200 mph, at which point the granulated coal, in a rotating
drum, would have been ignited by a gas flame. The gas that was subsequently
produced by the flame mixed with high‑pressure air to create thrust.
From 1941 Lippisch was greatly assisted by the high‑speed wind
tunnels developed in Germany that enabled test models to be subjected
to Mach 4.4 airflow. As Allied troops advanced into Germany, a number
of designers, particularly those involved in the Third Reich’s cutting edge
nuclear weapons and V2 programmes, were captured and moved to the
USA in Operation Paperclip. Lippisch was among their number. His
incomplete DM‑1, captured at Prien along with large quantities of research
documentation, was also shipped across the Atlantic.
NACA’s 1946 tests with the imported DM‑1 in its Langley Field wind
tunnel, assisted unofficially by Lippisch, revealed many problems with
stability, lift and drag associated with the thick wing. Papers based on the
captured German research were made available to the Consolidated Vultee
Aircraft Corporation (Convair), which was working on the USAAF’s
August 1945 requests for proposals for a supersonic point‑defence
interceptor (designated MX‑813) and a long‑range penetration/escort
fighter. The company won the interceptor contract on 25 June 1946
and began work on two prototypes. The aircraft’s role was similar to that
performed by the Me 163 – a short‑range, hard‑hitting fighter that could
climb to an altitude of 50,000 ft before engaging intruding bombers at
Mach 1.75 (1165 mph). Its endurance for that mission would barely
exceed six minutes.
Initially, Convair’s design used a 35‑degree swept wing, accepted at
the time as the optimum sweep‑back angle, combined with a V‑shaped
tail and rocket power. By May 1946 the initial MX‑813/XP‑92 design,
armed with four T‑31 20 mm cannon in its nose, was ready for USAAF
inspection. Wind‑tunnel tests showed that the MX‑813’s wing, spanning
31 ft 4 in, demonstrated poor low‑speed characteristics. The subsequent
use of a conventional tail unit was only a partial solution to these stability
problems. Different wing configurations that progressed gradually towards
a pure delta were examined, and Chief of Design Adolph Burstein finally
preferred a 60‑degree sweep delta wing, using data from Lippisch’s research
and the DM‑1 tests in NACA Langley’s wind tunnel. Delta‑wing research
by Michael Gluhareff at Sikorsky was also examined.
8 CHAPTER ONE A NEw ShAPE
After working at the USAAF’s Air Materiel Command at Wright
Field, Lippisch himself was seconded to Convair in October 1946 as a
consultant on the XP‑92 design. His research convinced the company’s
chief aerodynamicist Ralph Schick that a tailless delta format would be
preferable, as Burstein had thought. However, the Convair team strongly
favoured a thin delta rather than the thick, subsonic airfoils used in the
German designs. Simultaneously, Ed Heinemann at Douglas was working
on Lippisch‑inspired configurations for a project that would later emerge
as the US Navy’s jet‑powered F4D Skyray interceptor, which first flew in
January 1951.
The advantages of the delta compared with conventional swept or
un‑swept wings for supersonic flight were seen to be low transonic drag
increase because the delta structure enabled a thinner wing and an increase
in lift at speeds up to Mach 1. At high angles‑of‑attack the lift decreased
gradually without inducing unwelcome stall‑spin characteristics. It made
trailing‑edge flaps and a horizontal stabilizer unnecessary, although the
wing did tend to act as a massive speed brake at high angles‑of‑attack –
a characteristic that had to be considered as a disadvantage in aerial combat.
The long‑chord wing root allowed a lighter structure with considerable
fuel capacity and great rigidity. It prevented the ‘warping’ effect that was
being encountered with the thin, swept wings used on many contemporary
fighters that could cause adverse yaw or ‘aileron reversal’ – a condition in
which operating the ailerons had the opposite effect to the intended one.
Former F‑102A pilot Col Shaun Ryan also flew the F‑100 Super Sabre
and described the inherent difficulties of the latter fighter’s thin, 45‑degree
swept wing;
‘The F‑100 was faster on landing finals [than the F‑102] but it flew
and landed like an airplane should, except for one major difference –
adverse yaw. At high angles‑of‑attack, such as those used for landing, if a
wing dropped in a “Hun” [F‑100] you picked it up with the rudder, not
ailerons. If you used ailerons the aircraft would go opposite to the control
input. This was much more noticeable in a high‑G turn where, if you
used ailerons to steepen the bank angle, the plane could snap roll in the
opposite direction. You flew high‑G manoeuvres [in the F‑100] with your
elbows braced against the canopy rails to ensure that the ailerons stayed
in the neutral position.’
DELTA DATA
A mock‑up for the ‘augmented rocket’ version of the XP‑92 interceptor
was built in 1948 with a delta wing swept at 60 degrees. At that stage it had
a simple cylindrical fuselage, including a cockpit in a pointed nose section
that was located centrally in the air intake for the innovative engine. This
was a ducted ramjet motor powered by gasoline and boosted by a number
of internal rocket chambers. In appearance it echoed the fuselage structure
of the British Miles M.52 of 1945 and the French Leduc ramjet prototype
more than the Lippisch DM‑1, but it had a thin swept wing and V‑tail
instead of the straight flying surfaces of the planned Miles supersonic jet.
To avoid being sucked into the ramjet in an emergency bail‑out, the
pilot’s cockpit section would have been jettisoned with the rest of the
