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The Convair F-102 is a first generation supersonic
interceptor of the Century Series of fighters.
Influenced by the captured wartime work of Dr. Alexander
Lippisch, Convair engineers became convinced that delta
wings were the way forward for supersonic aircraft.
Their first attempt was the XF-92A demonstrator, a barrel
fuselage with mid mounted 60-degree delta wings, and an
Allison J-33 engine of 5,900 lbs thrust or 7,500 lbs
afterburner, it came close to breaking the sound barrier.
This ‘success’ was the green light for continued development
of the YF-102. The YF-102 was about 70% size of the service
aircraft which we are familiar with, and had a pointed nose,
air intakes just below the cockpit, delta wings, and a Pratt
& Whitney J-57 of 9,200 lbs thrust or 14,800 lbs
afterburner. More than enough power to go supersonic with.
However flight-testing revealed a VERY different story, as
the YF-102 stubbornly refused to go supersonic under any
conditions! At this time the USAF was not interested in a
fighter incapable of going supersonic, and was very close to
canceling the F-102 project.
However at this time a NACA aerodynamics specialist
called Richard Witcombe discovered the area rule, and it was
suggested that this be applied to the YF-102. Put simply –
an aircraft’s cross section, when plotted from nose to tail
would be as smooth a curve as possible.
In practical terms for the YF-102, it was modified to
have a longer and more tapered nose, slimmer fuselage where
the wings were attached, and a lengthened tail section
widened with the addition of two large bulges. Re-engined
with a J-57-P-11 of 10,200 lbs thrust or 16,000 lbs
afterburner, the aircraft was redesignated YF-102A and
easily broke the sound barrier on its second flight.
The service F-102 was powered by a similar or slightly
more powerful J57, giving it a maximum speed of 825mph at
36,000 feet. It was armed with 6 Hughes Falcon missiles
carried internally in the weapons bay, 3 being infra-red and
3 being radar guided. The F-102 served with the USAF from
April 1956 until 1978 with the ANG. 875 single seaters were
built.
The TF-102 was a side-by-side trainer version with full
combat equipment, 63 being built. The bulbous front end
compromised the newly discovered area-rule, and restricted
the TF-102 to subsonic flight only. Most served with the
4780 Air Defense Wing, providing training for F-102 pilots.
However all operational units had a trainer version for
pilot evaluation purposes.
As an aside, the F-106 Dart is a continuous development
of the Dagger, designed from the outset with knowledge of
the area-rule. With a J75 of 17,200lbs thrust or 24,500 lbs
afterburner, it achieved a maximum speed of 1,525mph at
40,000 feet. The fastest single engined aircraft ever!
THE KIT & CONSTRUCTION
The Hasegawa kit has been with us for some years now (I
don’t know it’s precise vintage), and is frequently
re-issued. I built my first Dagger (and Dart) in 1987, in
ADC overall gray, so knew exactly what I was getting. As I
remembered, it went together well, required no filler, and
looks every inch as an F-102 should. Superbly moulded in
Hasegawa's hard grey plastic, this kit is free of flash, and
a pleasure to build. The only shortcoming being that this
kit is not up to modern standards of interior detail and the
surface detail is raised, but that should be reflected in a
lower cost! It represents a superb example of first
generation Hasegawa at their finest, and is an excellent
start point for any F-102 Dagger project.
Although I think the Hasegawa kit shapes out well as an
F-102, I never measured my kit until this project, but am
very impressed with the results.
My second Hasegawa F-102 came courtesy of the Esoteric
Models sale at the 1998 IPMS Nationals.
The Hasegawa instructions are clear and concise, making
construction fairly straightforward, so I'll just
concentrate on the areas where I diverged from the standard
kit instructions.
Cockpit
Unsurprisingly, this bears no relation to the original,
the only shared component being the front undercarriage bay,
and this had to be modified by removal of the single
seater’s side consoles.
Cockpit starts with the floor, vac-formed as a single
part, I painted it Ash light grey from the Inscribe range of
acrylic paints, with black side consoles and installed
control columns made from sections of paperclip. Next came
the metal seats, which needed a little work to remove the
pouring points. Seats were painted black with green cushions
and red head and armrests. I installed harnesses from thinly
sliced Tamiya masking tape, and then installed the seats.
Front Fuselage
This is continuously dry fitted with the cockpit, as
these parts are nothing like as well fitting as the original
Hasegawa parts. The first task that can be completed is the
installation of the modified undercarriage bay. This gives a
base for the cockpit floor, such that the opening can be
trimmed to the correct shape and size. I painted the cockpit
walls light grey prior to cementing the cockpit floor to the
top of the undercarriage bay, such that the seats backed
upto the bulkhead. I installed a little nose ballast prior
to joining the front fuselage halves, fortunately it all
lined up ok, with the cockpit well centred.
With the front fuselage halves joined I was able to
smooth the seam, and install the instrument panel and
coaming. These were painted black.
Completing the Airframe
I mated the Hasegawa fuselage halves, and then began
checking to see where I should sever the original front.
Unfortunately the Xtraparts instructions are not very clear,
and the cut does not follow a panel-line, but the diagram
shows a line 6mm aft of the wing root. It was impossible to
check by dry fitting, so I took a deep breath and wielded my
hacksaw.
Now that I could check by dry fitting, I was horrified to
find that the weapons bay aperture was about 6mm short for
the cover! The line was in the WRONG place! Undeterred, I
smoothed the cut marks, and rejoined the severed fuselage
parts using tabs. After cooling down for a few days I cut
the fuselage again at a point coinciding with the leading
edge of the wing. This time the dry fitting indicated
success, so I joined the new nose, and began filing the join
lines. The wings were installed unmodified, followed by the
weapons bay doors. This is a single piece resin replacement
part by Aeroclub, which would fit the single-seat Hasegawa
kit perfectly. Mine required minimal trimming to compensate
for the new nose. Final touch was the metal air intakes,
which required a little cleaning up before fitting, but
fitted very well. At this point I primed the entire
airframe, to check that all my joins and seams were smooth
enough.
Canopy
I trimmed the canopy from its backing sheet, and was
horrified to find that it was undersize! In desperation I
trimmed the coaming, and installed raised cockpit side sills
to spread the rear section of the canopy a bit. This
achieved an adequate match for the rear section, but left
horrendous gaps around the windscreen. The canopy was fitted
using Humbrol Clearfix all round, several applications being
applied to fill the gaps at the front. Finally I used PVA
wood glue to smooth the front to an aerodynamic section. At
this point I noticed that the seats are very small, and a
pilot with head on the headrest wouldn’t be able to see over
the instrument panel. However after all that filling, the
cockpit was going to have to stay as it was.
Hasegawa suggest that Vietnam scheme F-102s should have
an infra-red sensor just ahead of the canopy, and this was
moulded on my original F-102. However, photographic evidence
suggests that this item is retractable, so I omitted it from
the TF-102.
Painting and Markings
I masked the clear sections of the canopy very carefully
with bare metal foil, leaving the frames exposed. Then I
handpainted the upper fuselage in Vietnam 3 tone camouflage
using Humbrol numbers 116, 117 and 118, following the
Hasegawa painting instructions. Underside was painted with
Inscribe Ash Grey with Inscribe Avocado as interior green
for the undercarriage bays. Nose radome is Humbrol 33 Black.
This was followed by several coats of Johnsons Klear prior
to application of decals. I apply my decals over a wet patch
of Klear as this gives no space for any air, and eliminates
the risk of silvering. The Xtra parts conversion includes an
appropriate serial number, and the instructions suggest
using kit decals and simply replacing the serial. This is
exactly what I did, and just hope that 0-41367 served with
the 62nd Fighter Squadron in Vietnam colour scheme at some
time.
After completion of decalling I coated the entire
aircraft with Humbrol Matt Cote to dull it down, prior to
removing the canopy masks. On this occasion the masks came
off cleanly without tearing any framing or cracking those
joints around the canopy.
Finishing Off
Nearly there, the rest is straight forward, with no more
hidden traps. Jetpipe and arrestor were painted gunmetal and
installed after completion of painting. Undercarriage was
painted with Humbrol Aluminium with silver oleos prior to
installation. Wheels are Aluminum with Aeromaster Tire Grey
tyres. The air data probe was again Aluminium, and required
the drilling of a very straight hole into the tip of the
radome.
Voila! the TF-102 project is complete, and a very
different Dagger joins my miniature air force.
Accuracy
For the purposes of completeness (and for only the second
time ever), I have measured the models, multiplied the
measurements by 72 to see how large the model would expand
to. Then I obtained dimensions from my reference books, and
calculated the difference - to explain it away.
F-102
Height. Model built without undercarriage, so use TF-102
figures.
Span 162mm, x72= 11664mm, 11.60M, Diff = 64mm
Length 284mm with probe, x72= 20448mm, 20.82M, Diff=
372mm
TF-102
Height 90mm, x72= 6480mm, 6.45M, Diff = 30mm
Span 162mm, x72= 11664mm, 11.60M, Diff = 64mm
Length 282mm in probe, x72= 20304mm, No Figures
As you can see, the model is extremely accurate, with
discrepancies probably down to my crude measuring
techniques, or inaccurate length of the probe. They
certainly look the part!
CONCLUSIONS
Overall I am delighted with the outcome of my TF-102
Dagger Trainer, despite any shortcomings that I have
mentioned. The difficulties with the fuselage length, and
the canopy all added to the satisfaction of the project, and
completion has the added reward that I have NEVER seen
another completed example at any model show.
Although I never had the pleasure of meeting Jim Wood, I
hope he would approve of what I did with one of his kits. |
