Northrop F-20 Tigershark
1/144 LS kit (cat.nr. 1053)

Introduction

The Northrop F-20 evolved from the F-5G design study, which in turn evolved from the F-5E.
Northrop proposed the F-5G as modernized F-5E fitted with a more powerful single engine and larger horizontal tail fins.
The F-20 design went much further than the initial F-5G, including state-of-the-art avionics, digital fly-by-wire and a digital multi mode AN/APG-67 radar set. It also incorporated some unique aerodynamic features that were applied before to the YF-17 design.
Another change to the initial F-5G design was moving the tail fin assembly further back by about 9in, all of the actual F-20 airframes had the tail fin in this location.

As part of the FX program the F-20 was proposed as a lower-cost export alternative to the F-16A and Northrop made sure to prove that it could match or better the F-16A.
The F-20 development program ran from 1982 until November 1986, when a political decision to allow F-16A to be exported to non-NATO countries ruined any chances of F-20 sales.

Three F-20 airframes were completed:

The first airframe bears a closer resemblance to the original F-5G design by using F-5E nose and cockpit sections, the second and third airframes were built to full F-20 specs and were fitted with a 'panoramic' canopy.

Over time three different paint schemes were applied:

• red/white high visibility scheme (mock-up and Nr.1 at roll-out and 1983 Paris Salon);
  
• two-tone camouflage gray (Nr.1 after 1983 Paris and Nr.2 at roll-out);
  
• gloss metallic gray (Nrs.1 and 2 at 1984 World Tour and Nr.3 at roll-out).
  

Between 1983 and 1986 one or two F-20s would be present at about every major Air Show, including shows in Europe and Asia, showing off with a spectacular flying display.
In 1984 Nrs.1 and 2 went on a tour around the world (including the Farnborough Air Show) whilst Nr.3 was used for weapons testing.

stores

Wing tip missile launch rails were always fitted, with each rail loaded with either an AIM-9L missile or a 'Smokewinder' smoke-generating pod for display flights.
For long flights up to three 275gal aux fuel tanks could be fitted to the centerline and inside wing pylons, these were the same tanks that were also used on F-5E/F.
Dimensions of the 275gal tank: diam 24.00in (1/144: 4.23mm); len 209.60in (excl fins) (1/144: 37,0mm).
There were plans for a fuel tank of 330gal capacity but this was never fitted to any F-20.
The 330gal tank was to be a larger version of the 275gal tank with the center section stretched by 28in to arrive at 237.60in len (excl fins, 1/144: 41.9mm) and fitted with larger horizontal fins.

The kit(s)

In 1984 LS released a 1/144 scale kit of the F-20.
After LS went bankrupt the F-20 patterns were bought by ARII who still does occasional re-releases of the kit.
As far as I know the LS kit was copied twice: once by CC Lee and once by Trumpeter.
The CC Lee kit is a decent clone of the LS kit.
In 1989 Airfix added a 1/144 F-20 kit to its line-up, this kit came with decals for the 3rd aircraft in gloss metallic gray scheme so I bought one, but the kit itself turned out to be a rather poor Chinese copy of the LS kit. The main sprue is marked 'F-1324', which matches the catalog number of the Trumpeter 1/144 F-20 kit.

The LS kit captures most of the design characteristics of the F-20 well.
A few things that can be improved are:

construction

• The right-hand side of the rear fuselage is not as much curved inwards as the left-hand side, this should be made symmetrical.
  
• The wing-fuselage section does not fit flush with the lower fuselage, the recess in the fuselage sides needs to be made slightly larger.
  
• the nose wheel leg is 1mm too short, this can be fixed by fitting a piece of plasticcard in the wheel well on which the leg is mounted.
  
• due to the way the fuselage halves are molded, the top of the gun barrels are flush with the nose, the look can be improved by cutting a small v-shaped grove on the inside of each barrel, with one side of the V-shape flush with the nose and the other one vertical against the barrel.
  
• the seat is molded in with the rear of the cockpit tub, making it sit too far back. A new (Stencel S-III-S) seat should be positioned further forward by some 2mm with some representation of the canopy hinge scissors added behind it.
  

accuracy

• The tail fin assembly needs to be cut off along the top of the fuselage and moved back by 1.5mm (see picture, top is original kit).
  
• The spine of the kits fuselage tapers towards the rear fin, however its width should remain constant aft of the flap hinge lines (I had not noticed this when building my first LS F-20 kit).
  
• The shape of the Karman fairings should be more complex towards the rear, with the tail cone 'sitting on top of it'.
  
• The F-20 nose is slightly wider and more curved than an F-5E nose: with an F-5E the nose starts to taper at the rear of the gun bays, with an F-20 the taper starts at the front of the gun bays. In side view the lower side of the F-20 nose is more curved. The nose shape of the LS kit is somewhere in between the two in top view, in side view it is spot-on.
  
• A pitot tube should be fitted to the starboard side of the nose, below the windshield.
  
• The F-20 wing root leading edge extensions have a 3.6° downward angle starting over the wing leading edges, those in the kit are too straight and the leading edges too blunt.
  
• The leading edge flaps in the kit are not full span but end 1.4mm (8in at full scale) inboard of the tips, this is accurate for Nr.1, but Nrs.2 and 3 had full span LE flaps.
  
• Small Tip EXtension strakes have to be added between the wing tip leading edges and the missile rails, these are featured on the box art but are not in the kit.
  

Back in 1985 I completed an LS F-20 kit and finished it as the second aircraft in two-tone gray camo scheme using the kits decals.
I also had started building a second kit and later I acquired an incomplete third kit, which I started converting into an F-5E (only to abandon it later when Dragon announced an 1/144 F-5E kit).
Apart from that I received a CC Lee F-20 kit.

Recently I looked into completing the kit I had already started and also made plans to turn my abandoned third kit into the nr.1 aircraft using bits from the Airfix kit.
As I need the fuselage halves of the complete LS kit as a reference for turning the abandoned kit back into an F-20, first thing to do is restoring the rear fuselage of the abandoned kit.
Once that fuselage is restored, its nose needs to be replaced by one cut from a Revell F-5E kit (either cat.nr. 04018 or 04003), again using the LS kits fuselage halves as a reference for getting the length of the nose right (base of windshield to rear edge of fuselage).
The nr.3 aircraft can be completed once the fuselage of the nr.1 aircraft is converted.

After reading the 2023 'Northrop F-20 Tigershark' book by Paul Metz and inspecting my CC Lee F-20 kit, I changed my plans and decided to turn the CC Lee kit into the nr.1 aircraft and turn the abandoned third LS kit into another nr.3 aircraft in its final 'Big Nose' guise.

This page is split into four build reports:

• Aircraft Nr.1, CC Lee/Revell bash
  
• Aircraft Nr.2, LS kit
  
• Aircraft Nr.3, LS kit
  
• Aircraft Nr.3 Big Nose, LS/Airfix bash
  
  

References

• 'Northrop F-20 Tigershark', Paul Metz, Air Force Legends Nr.228, ISBN 9-798985-472660
  
• Walkaround at IPMS.nl of F-20 Tigershark GI1002 as displayed in the California Science Center
  
• Northrop Flight Test: F-20 Tigershark pictures on Britmodeller
  
• F-20 described on DetailedPedia
  

Aircraft Nr.1

For this model I decided to use the CC Lee kit.
The CC Lee kit is a decent clone of the LS kit: sprues differ, recessed panel lines are a bit softer and some small details are missing, but otherwise the kit matches the LS kit so well that parts of one kit will fit the other one perfectly.
A very similar looking F-20 model kit was also sold by Taiwanese company Huan Chiu, I found this kit mentioned on Korean 'acme97' scale modelling blog.
Over the years CC Lee kits came with either self-adhesive stickers, decals with a wrong font type for 'F-20' and 'F-20 Tigershark' texts or improved decals with correct fonts. You may also find a combination of either decal or sticker sets in one kit.
For the red/white scheme I won't be needing any of the kit decals anyway.

Construction

Some general changes need to be made:

• The tail fin assembly needs to be moved back by 1.5mm.
  
• The F-20 wing root leading edge extensions have a 3.6° downward angle starting over the wing leading edges, those in the kit are too straight and the leading edges too blunt.
  
• Small TEX strakes have to be added between the wing tip leading edges and the missile rails.
  
• The TEX strakes should fit flush against the leading edges.
  

fuselage

The fuselage of the Nr.1 airframe differs from the others in a number of ways:

• the entire forward fuselage section of an F-5E was fitted, resulting in a slightly sleeker and more straight nose and a canopy with a smaller clear area.
  
• There is a vent in the port side of the rear canopy frame that is unique to this airframe.
  
• A large UHF aerial was mounted on the top of the spine.
  

For a 1/144 F-5E forward fuselage section there is a choice of two kits: a Dragon F-5E or a Revell (G) F-5E.
The Dragon kit comes with a separate forward fuselage to allow for an F-5F dual, however the cross-sections of the Dragon nose and the LS F-20 fuselage are a poor match.
The Revell F-5E kit matches the cross section of the F-20 better but there the nose needs to be cut off of the fuselage.
I picked a Revell F-5E 'Patrouille Suisse' kit (cat nr.04003) for a donor.

Painting

For first F-20 the spectacular red/white roll-out scheme is an obvious choice.
Fortunately I managed to find a nice set of 1/144 scale F-20 decals made by TripleNuts ("F-20/F-5E/F Vol.1", cat.nr.TN-004) which includes a set of stripes for the red/white color scheme of the nr.1 aircraft.

The red used for this scheme appears to be Insignia Red, I could not find any details on the exact paint color used.

Aircraft Nr.2

Construction

Construction of this kit was straightforward, no additional changes need to be made, aside from:

• The tail fin assembly needs to be cut off along the top of the fuselage and moved back by 1.5mm.
  
• due to the way the fuselage halves are molded, the top of the gun barrels are flush with the nose, the look can be improved by cutting a small v-shaped grove on the inside of each barrel, with one side of the V-shape flush with the nose and the other one vertical against the barrel.
  
• the nose wheel leg is 1mm too short, this can be fixed by fitting a piece of plasticcard in the wheel well on which the leg is mounted.
  
• Small TEX strakes have to be added between the wing tip leading edges and the missile rails, these are featured on the box art but are not in the kit.
  

I fitted just the Sidewinder missiles from the kit to the wing tip rails, no pylons nor stores.

fuselage

The recesses in the fuselage sides for the wing center section had to be trimmed to make it fit flush with the lower side.
The joins between the intakes and the fuselage and between the wing center section and the lower fuselage needed some filler.

Painting

Aircraft Nr.2 initially flew in the camouflage gray scheme. For the 1984 World Tour it was repainted in the gloss Ascot Gray scheme.
The kit decals are accurate for Nr.2 in camouflage gray. This scheme uses the same colors as the early F/A-18 color scheme, with registration and anti-glare panel painted in FS.35237.
I decided to paint the anti-glare panel on the nose by hand instead of using the kit decal and mixed some Polly S paint to match the decals.

Aircraft Nr.3

Construction

Construction of this kit is straightforward, no additional changes need to be made, aside from those listed above and:

• The leading edge flaps should be full span and continue behind the TEX strakes, there should be a small gap between the strake and the flap leading edge
  

I am considering fitting two auxiliary 275gal fuel tanks to the inboard wing pylons to represent the aircraft as it traveled to and from air shows.
The F-20 kits only contain a single 275gal fuel tank each but fortunately I have stores of multiple kits.
'Plan B' would be to fit a pair of scratch-built 'Smokewinders' to the wing tip rails instead.

Painting

Aircraft Nr.3 only ever flew in the gloss metallic gray scheme.
The gloss metallic gray paint used was an automotive lacquer but sources disagree on the exact color used: some mention "1983 Mercedes Benz Anthrazitgrau Metallic 172" , but the Paul Metz book and others (including the painting guide in the 1/48 Monogram F-20 kit) mention BMW Ascot Gray ("1981 BMW Ascotgrau Metallic 151") , a true gray gun-metal shade.
For the gloss metallic gray scheme the civilian registration numbers and tail fin tip appear to have been painted in FS.36270, the radome was either FS.36270 or gloss black and a flat black glare patch was painted on the nose.
At the time of the 1985 Paris Salon air show the aircraft had just received a fresh coat of paint, the radome was also painted Ascot Gray and no black glare patch was applied.

Aircraft Nr.3, Big Nose

Finding out about this version was one of the many surprising facts I found when reading the 'Northrop F-20 Tigershark' book by Paul Metz.
If you look closely at the Nr.3 aircraft as it is displayed at the California Science Center you may notice that the nose contours look a bit odd and the gun bay access doors extend further down (plus the engine nozzle is missing).
Right before the F-20 program got canceled, Nr.3 received a 'nose job': it was found that the AN/APG-67 radar set would perform much better with a larger antenna, to fit this larger antenna the nose had to be made slightly deeper and wider.
Aircraft Nr.3 was fitted with the new larger nose section for aerodynamic testing, aircraft Nr.4 was to receive the complete enhanced radar set as well but was never completed.

Construction

Long ago I had started to convert the fuselage to an F-5 by cutting down the rear.
Now that I want to turn it back into an F-20 I need to undo the changes by grafting parts of the rear fuselage of the Airfix/Trumpeter kit onto the LS fuselage halves.
Apart from that some general and specific changes need to be made:

• The leading edge flaps should be full span and continue behind the TEX strakes, there should be a small gap between the strake and the flap leading edge
  

fuselage

The bigger nose section was made both deeper and wider by reducing the taper of the nose, an entirely new radome was fitted.

• In top view the nose used to begin tapering at the front of the gun bay hatches; the wider nose starts tapering further forward.
  
• In top view the new radome looks more like an F-16 radome, so needs reshaping (or replacing ?).
  
• The gun bay doors extend all the way down to the bottom of the fuselage, the latches are now just beyond the curved lower edge.
  
• The design calls for a grid of small pressure relief vents in the gun bay doors but these are not present on #3 as displayed.
  

Before reshaping the nose section the rear fuselage needs to be restored.
When I attempted to turn the F-20 kit into an F-5, I started by cutting down the rear fuselage and cutting back the wingroot leading edge extensions before abandoning the conversion.
It would be easier to use the rear fuselage of the Trumpeter kit than to restore the modified LS fuselage, however the Trumpeter plastic is thin and the shape of the rear fuselage is off, so that won't work.
Instead I cut some wedges out of sprue and inserted one in each of the fuselage sides. I left a 'T'-shaped ridge at the inside of each wedge to fit against the insides of the fuselage.
Before gluing the wedges in place I sanded the yellowed traces of glue off of the mating surfaces as these were not responding to glue, I also chipped off any old filler as that had turned brittle.

After fitting the wedges I heat-stretched some sprue and used that to fill any gaps.
First step in restoring the rear fuselage is adding a missing piece to the gap in the top.
I used half of a Hasegawa 1/24 F-104G (cat.nr.1002) wing fuel tank (part nr.B19) as its center section has the exact same diameter as the rear F-20 fuselage.
I trimmed both the cutout in the F-20 fuselage and the replacement part until an exact fit was achieved. I left a small section of the tank protruding behind the fuselage to help with alignment.
The forward section of this fuel tank has about the right amount of taper to be used for replacing the F-20 spine, I already cut out the section that matches the shape of the spine best.


The shape of the nose section of the Airfix kit is off for a regular F-20 but it might work for the big nose, however the plastic is not thick enough to sand the nose down.

Painting

Identical to the Nr.3 aircrafts usual gloss metallic gray scheme, apart from having no more 'F-20 Tigershark' text on the revised nose and the civilian registration now painted in flat black.
For the gloss metallic gray scheme the tail fin tip appears to have been painted in FS.36270, the radome was FS.36320 and a flat black glare patch was painted on the nose.

Trumpeter and LS F-20 kits compared

Some pictures of the main parts of both kits compared show why I consider the Airfix/Trumpeter kit to be a poor LS copy.
The sprue layout and the way the Trumpeter model is split into separate parts is almost identical to the LS kit, too close to be an original design IMHO.
The white model in the pictures is the Trumpeter kit, the gray one is the original LS kit. I did not bother adding the intakes to the Trumpeter kit as those only make it look worse.



The most obvious faults of the Trumpeter kit summarized:

• the sides of the nose/forward fuselage are too flat,
  
• the forward fuselage is too tall and too wide,
  
• the spine of the fuselage is too wide and tapers off at too shallow an angle,
  
• the Karman fairings (between the wing and the tail planes) are too tall,
  
• the vertical tail fin is too small in chord and the angle of the leading edge is too steep,
  
• tail planes are too thick and have blunt edges,
  
• lower fuselage center section between the wings is about 1mm too thick,
  
• 
  

The Trumpeter kits canopy (at top and left in the picture) deserves a special mention as it is too large in all dimensions and the rake of the windshield is too steep, making it look more like a WW2 fighter canopy.