Republic F-109C "Thunderdart"; 121st FS, 113th FW, (District of) Columbia ANG

Dizzyfugu · June 28, 2013, 12:33:10 AM

Here is Republic's final independent design that actually made it into service: the F-109 "Thunderdart"!

Some background:
The F-109 started life as a privately funded light fighter program by Republic under the handle AP-95 in the mid-1950s, aiming at export markets which were about to replace their 1st generation jet fighters like the F-86 or F-84 and air forces which could not afford or simply want the heavy supersonic fighters under development at that time. In the USA, it was also aimed at the replacement of these Korean War era types in the Air National Guards.

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

The AP-95 was inspired by both Lockheed's CL-246 (the later F-104 Starfighter) and Northrop's N-156 Light Fighter concept (which eventually developed into the highly successful F-5 fighter family, aiming at the same niches. In size and performance the aircraft fell more or less in between these two design – it was heavier and larger than Northrop's project, and a less radical alternative to the CL-246. Republic's design team started the development in 1955 and relied heavily on the huge F-105 fighter bomber that had been under development at the time, but the AP-95 was to be a pure interceptor. The basic idea was "to build a relatively small and highly aerodynamic fighter around the same engine that drives the F-100, but focusing on high performance and low cost of maintenance, as well as good field performance."

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

Actually, the AP-95, called "Thunderdart",was revealed to USAF officials for the first time as a full-sized mock-up in early 1957, and it looked much like a scaled-down F-105. It combined a slender, area-ruled fuselage with highly swept wings and a conventional, low tail.

The nose offered space for a relatively large radar dish. The air intakes were placed in the wing roots, with Ferri-style, forward-swept leading edges that had also been used on the F-105 and other Republic designs like the AP-75 interceptor.
From the F-105 the landing gear concept had been borrowed, too. The long main legs retracted inwards into the wings, leaving only the outer wings free for ordnance loads, but allowed much space in the fuselage for fuel and avionics. The aircraft was to be powered by a Pratt & Whitney J57-P-21 turbojet, with a dry thrust of 10,200 lbf (45 kN) and 16,000 lbf (71 kN) with afterburner.

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

The basic armament of the AP-95 was an internal 20 mm (.79 in) M61 Vulcan Gatling gun, which had a rate of fire of 6,000 rounds per minute. The cannon, mounted in the lower part of the port fuselage, was fed by a 725-round drum behind the pilot's seat. Additionally, the AP-95 was able to carry up to four AIM-9 Sidewinder AAMs under its wings. Total external payload was 6.000 lb (2.727 kg) on five hardpoints, a centerline pylon under the fuselage was "wet" in order to take a single drop tank. Alternatively, iron bombs or napalm tanks could be carried in a secondary ground support role.

The AP-95 was an attractive design but faced a strong competition, if not opposition. Among USAF officials it was not popular, because it was - despite its basically good performance and low development risks - regarded as an inferior aircraft. It did not reach Mach 2 (what the F-104 promised, despite many other weaknesses), and adding a complex radar system (which would have allowed longer range AAMs like the AIM-7 Sparrow) with an additional operator would further reduce performance.
The aircraft shared a "bad image" fate with the later F-5, which became nevertheless very popular in oversea markets due to its simplicity, versatility and efficacy. On the other side, Europe was already in Lockheed's strong grip, as the F-104G had been selected as NATO's standard fighter bomber - under dubious circumstances, though, but it successfully blocked the market.

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

Anyway, the AP-95 was nevertheless a capable aircraft which was more cost-effective than the thirsty and short-legged F-104, or the larger F-102 and F-106 which formed the air defense backbone at that era. While the US Air Force did not want another type in its arsenal, it was decided to buy and build the aircraft as a state-of-the-art replacement for the ageing ANG Sabres and Thunderstreaks, with the prospect of delivery of the type to NATO partners all over the world, too.

The original design was quickly approved and the AP-95 prototype made its maiden flight on October 10th, 1960, only equipped with a basic AN/ASG-14T ranging radar. After completing trials and further development with two further YF-109 pre-production aircraft, the Thunderdart was officially introduced as F-109A in March 1962 to the USAF. These production aircraft now featured an AN/APQ-83 radar for night and all-weather interceptions. Additionally, one of the YF-109 was modified in late 1962 to carry a second crew member under a lengthened canopy and with reduced internal fuel - it was planned as a F-109B trainer, but did not find interest since the T-38 already offered supersonic performance at much lower cost, and the Thunderdart's range suffered considerably. The F-109B remained a one-off.

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

In 1964 the F-109A was also introduced to the US ANG forces and attained some interest from other countries, including Spain, Italy, Turkey, Greece, South Korea and Japan. Most of these foreign countries settled for the Starfighter in the 60ies, and the door for the F-109 was closing: As a result of winning the International Fighter Aircraft competition in 1970, a program aimed at providing effective low cost fighters to American allies, Northrop introduced the second-generation F-5E Tiger II in 1972. This upgrade included more powerful engines, higher fuel capacity, greater wing area and improved leading edge extensions for better turn rate, optional air to air refueling, and improved avionics including air-to-air radar. It became a great success and made the F-109 obsolete, which lacked further development potential and was too limited to its interceptor role to be a versatile option for smaller air forces.

From 1962 until 1965, a total of 145 F-109As were built. Compared with the 1.400 Tiger II versions until 1987 only a very small number, and further orders from the USA did not materialize, even though the Thunderdart showed good flight characteristics.

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

As a final attempt to improve the Thunderdart's potential, 80 F-109A aircraft were modernized from 1969 on, all of them ANG aircraft. These machines received a more powerful J57-P-20 engine, rated at 18.040lbf (8.200kN) thrust at full afterburner – which finally allowed to break the Mach 2 barrier.
On the avionics side, a new AN/APQ-124 radar was fitted – which still did not allow the guidance of medium range missiles, though, the AIM-9 remained the Thunderdart's primary weapon. Further enhancements included a more modern firing system and an AAS-15 infrared sensor. These updated aircraft received the designation F-109C, and the MLU phase lasted until 1972. Externally these modified aircraft could easily be identified by the bigger radome and the added IR sensor pod under the nose.

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

No F-109 was ever used in combat, despite the raging Vietnam War. The original F-109As remained with the USAF, but these were only used for training purposes or as instructional airframes on the ground. These F-109As were quickly phased out during the 70ies, the last one in September 1977. The modernized F-109C soldiered on with several ANG forces until 1985, being replaced by F-4 and F-16 as interceptors and multi-role combat aircraft.

Republic F-109A "Thunderdart" by Franclab, on Flickr
(This wonderful illustration was done in less than 24h by fellow user Franclab from flickr.com - many thanks for this "present"!

)

F-109A general characteristics
Crew: 1
Length: 56 ft 9 ¼ in (17.02 m)
Wingspan: 25 ft 7 in (7.81 m)
Height: 15 ft 9 ¼ in (4.82 m)
Wing area: 277 ft² (25.75 m²)
Empty weight: 14.000 lb (6.350 kg)
Loaded weight: 20.640 lb (9.365 kg)
Max. take-off weight: 29.027 lb (13.170 kg)

Powerplant
1× Pratt & Whitney J57-P-21 turbojet with 10.200 lbf (45 kN) dry thrust and 16.000 lbf (71 kN) with afterburner:

Performance
Maximum speed: Mach 1.86 (1.225 mph, 1.975 km/h) at 36,000 ft (11.000 m)
Combat radius: 450 mi (730 km)
Ferry range: 1.735 mi (2.795 km) with external fuel
Service ceiling: 58.000 ft (17.700 m)
Rate of climb: 31.950 ft/min (162.3 m/s)

Armament
1× 20 mm (0.787 in) M61 Vulcan gatling cannon with 725 RPG
5 hardpoints for 6.000 lb of ordnance (2.727 kg); typically 2× or 4× AIM-9 Sidewinder under the wings, plus an optional drop tank under the fuselage.

The kit and its assembly
This is a totally fictional aircraft with no real paradigm. The initial idea was that I wondered if one could not make something from an early MiG-21F with its small diameter air intake, when this would be replaced by a radome?

That the project eventually evolved into a kind of anti-Starfighter came through the wings: there was the problem of placing the air intakes somewhere. To solve that problem I remembered the Tamiya 1:100 F-105 kit, I built one years ago and it's still available, even though I had to import a NIB kit from Hong Kong for this occasion. Calculations had indicated that the wing size and span would match a 1:72 MiG-21 well, and so the F-109 was born. The Thunderchief's air intakes are SO characteristic that anything else than a Republic design was out of question, the rest was spun around this basic idea.

As a side note: the F-109 designation had never been officially allocated. While the Bell D188A VTOL fighter is often cited as "YF-109", this designation was a marketing invention of the Bell company. "F-109" had NEVER been used. Douglas had also used the F-109 code for an F-101 development, but also only for internal purposes.

But back to the model itself: the whole thing is a true Frankenstein job, puzzled together from a lot of bits and pieces. The most important ingredients:

● Fuselage from a 1:72 Academy MiG-21F, incl. canopy
● Radome from a 1:72 Hasegawa F-4E
● Wings, pylons and main landing gear from a 1:100 Tamiya F-105
● Stabilizer fins from a 1:72 Revell F-16, shortened
● Main wheels from a 1:72 Hobby Boss F-86F
● Fin from a 1:100 Il-28(!)
● Horizontal stabilizers from a 1:72 Matchbox A-7E w. reduced span
● Front wheel from an 1:72 Italeri A-4M
● Engine nozzle from a 1:72 Matchbox F-104G
● The afterburner inside is actually a sprocket wheel from an 1:72 ESCI M1A1 Abrams
● Cockpit tub and dashboard come from a 1:72 Heller Alpha Jet
● Seat and pilot from Matchbox (unknown origin)

1:72 Republic F-109C "Thunderdart" (Whif/Kit-bashing) - WiP by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart" (Whif/Kit-bashing) - WiP by dizzyfugu, on Flickr

The MiG-21 lost any characteristic detail (blow-in doors, 30mm cannons, slots for wings and stabilizers, even its fin and spine), and the landing gear wells were covered. The F-105 wings were placed slightly lower on the fuselage side. The fin was simply replaced, the tail a bit shortened and the new/bigger nozzle attached. The new nose had almost the same diameter as the original air intake piece from the Academy MiG-21F. For the Corsair II stabilizers, 'consoles' were added on the lower rear fuselage, so that they could also be placed in a lower position.

My plan/wish was to make the thing look as little MiG-21ish as possible, and IMHO I succeeded well. Actually, the Thunderdart reminds a LOT of the much bigger F-105, and there is also a lot of F-101 in it, too, despite its ADC livery? You take at least two looks, since proportions are different from the F-105, yet the thing looks VERY familiar... "Could it have been...?"

External loads were limited to just two AIM-9 training rounds with launch rails under the outer pylons, even though all wing pylons were fitted (the Tamiya kit has large slots to hold them, I was too lazy to fill them).

The cannon bulges, the IR sensor as well as some air scoops and antennae were sculpted from simple pieces of sprue or styrene.

Painting and markings
As an USAF/ADC interceptor, an overall Aircraft Grey (FS 36473, used ModelMaster 1731) was clear from the start – and it's actually a fine option, as the F-105 as lookalike benchmark was basically only operated in bare metal or SEA camouflage. An ADC aircraft would be deceiving, too, and provoke third looks.

The cockpit interior was painted medium grey, the landing gear wells in interior green and the air intakes in white with red trim.

Anyway, making an ANG aircraft from this base was more tricky. At first I wanted to create an Oklahoma ANG aircraft (had some nice markings for the fin, but they turned out to me too large since they belong to a modern F-16...), but finally settled on a D.C. Air Guard aircraft since I had such fuselage markings from a F-86H at hand.

Basic tone is an overall FS 16473 ADC Grey (Testors 1731), some panels on the upper side and the flanks were highlighted with a slightly lighter grey (FS 16515). The cockpit front area received a flat black anti-glare panel, to which a black trim was added - F-106 style, and this turned out to be VERY characteristic, if not deceiving! Around the rear fuselage some heat marks – reminiscent of the F-100 – were added through metallizer (Steel and Titanium, partly mixed with Humbrol 113, Rust) and some dry-painting. The kit was then lightly weathered through a thin wash with black ink and very light dry-painting with pale grey.

1:72 Republic F-109C "Thunderdart" (Whif/Kit-bashing) - WiP by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart" (Whif/Kit-bashing) - WiP by dizzyfugu, on Flickr

The colorful fin markings were designed by myself – inspired by a 2008 postal stamp from the 'Flags of our Nation'series. My fin decoration is purely fictional, though, and incorporates the D.C. flag (two red horizontal bars on a white ground, with three red stars above) as well as some iconic cherry blossoms, as these seem to be a local identity symbol? Additionally the fin features on one side the District of Columbia Sign, on the other side the Eastern Air Defence Sector badge. The fin decoration was created on a PC with Corel Draw and printed on Experts' Choice white decal paper with an inkjet printer at 600dpi - even though the touchy decals suffered under the soaking process... A lot of cosmetic correction had to be done by hand/brush, it's far from perfect, just the result of my first large scale self-.made decal experiment. The rest of the markings were puzzled together from the scrap box.

1:72 Republic F-109C "Thunderdart" (Whif/Kit-bashing) - Making decals by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart" (Whif/Kit-bashing) - WiP by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

After painting and decals, the kit received an overall coat of semi-gloss Humbrol varnish, since I wanted a slight shine but not a hi-gloss finish. The anti-glare panel was covered with matt varnish - which did not dry up properly, leaving a milky film. Nevertheless, it looks like sun-bleached black paint, so I kept it. Undesired side effect... The radome was painted with gloss varnish, so that three shades of black meet at the Thunderdart's nose.

1:72 Republic F-109C "Thunderdart"; BuNo 62-28502 of 121st Fighter Squadron, 113th Fighter Wing; (District of) Columbia Air National Guard; Andrews Army Air Field, summer 1972 (Whif/Kit-bashing) by dizzyfugu, on Flickr

A major kitbash. The Thunderdart looks unspectacular, but it is IMHO very deceiving. It combines characteristic elements of various Century fighters in shape and color, and it should keep some folks wondering what's actually wrong about it... Sleek aircraft - behold what's in a simple 1st generation MiG-21!

tahsin · June 28, 2013, 12:45:31 AM

Cries out: "Field me, field me."

I knew Dizzyfugu has always something that deserves the accolades, but as a 105 fan, I find this particularly appealing.

Dizzyfugu · June 28, 2013, 01:09:26 AM

Thanks a lot! Yes, this thing cries "105" at first glance, but then the proportions are not right and you start to wonder what's wrong with it...

Anyway, this project made me wonder if a F-105F (or G) with a bigger radome, some serious AAMs and in ADC Grey would not look cool? It could have been sold to Canada, instead of the F-101Bs?

rickshaw · June 28, 2013, 01:48:15 AM

Very nicely done and presented...

PR19_Kit · June 28, 2013, 02:33:50 AM

A REAL tour de force this time Thomas!

The 1/100 scale F-105 wings are a touch of genius, and the back story is so typical of the American defence purchasing process that it screams 'real'!

Of course if it was British we'd have built the first five pre-production aircraft and then cancelled the whole project.......

Weaver · June 28, 2013, 04:07:15 AM

Well it got me: I was convinced you'd scaleorama'd a 1/48th cockpit into a 1/72nd F-105.....

Great piece of work - very well done!

Dizzyfugu · June 28, 2013, 04:38:55 AM

Thank you both!

Logan Hartke · June 28, 2013, 08:13:52 AM

I like it, Dizzy! It definitely looks like a Republic design, so job well done there. To my eyes, it does look like an American Su-15, though. I like it!

Cheers,

Logan

sandiego89 · June 28, 2013, 03:13:57 PM

Top notch, really like the small details like the IR sensor, splinter plate, etc. Think a tank on your wet centerline store would look great. Well done!

Ed S · June 28, 2013, 04:48:29 PM

Brilliant concept and an excellent kitbash. Well done.

Ed

Dizzyfugu · July 01, 2013, 12:11:12 AM

Thank you all, your feedback is highly appreciated!

albeback · July 01, 2013, 01:15:17 AM

I like the idea of the full width radome on the MiG fuselage.I'm about to start work on a 1/48 SU22. I also want to fit it with a radome similar to your model. This would of course involve new intakes. My original idea was to build side intakes above each wing but, the double curve of the upper fuselage would make shaping quite awkward. Instead, I decided to go for nose intakes either side - I got the idea from the Sukhoi T-49.

The result will be pretty ugly but a lot simpler. Besides, the Fitter isn't exactly pretty anyway!! Lol!

. Actually, I rather like the rather brutal, menacing look of the thing! Give me one of those instead of a dinky toy F-16 any day!

Your concept is quite ingenious. I like it!
Another of my mad ideas is to combine the cockpit,fuselage,wings & undercarriage of the Airfix 1/48 Lightning with the fuselage/tail of the KP SU-7 to produce a sort of single engine Lightning. Have you considered the SU-7 for any of your projects? I think it would look good with this sort of treatment

Allan

Dizzyfugu · July 01, 2013, 02:05:20 AM

The Republic Ferri intakes are great when you want to add these to an aircraft which originally has a nose intake. Adding airtakes IS tricky, since you normally have to widen the fuselage for the air ducts, and the wing roots solution is very elegant for a conversion - that's why I ended up the the 1:100 F-105 wings on my project. And they look SO characteristic that it was IMHO impossible NOT to make a Republic aircraft from the thing...

Not certain if 1:48 wings of a F-105 can be easily obtained or a conversion kit of some kind, but these should fit in size and shape on a Su-22? An F-84F is also an option, as well as a Hawker Hunter?

Somewhere I have seen A-4 air intakes transplanted onto a Su-22 - but IIRC it was just a CG experiment, not true model hardware. But I could imagine that it might work - maybe add some splitter plates, though?

Anyway, a "closed-nose" Su-22 should look awesome - looking forward to the result!

albeback · July 01, 2013, 05:21:21 AM

Quote from: Dizzyfugu on July 01, 2013, 02:05:20 AM
The Republic Ferri intakes are great when you want to add these to an aircraft which originally has a nose intake. Adding airtakes IS tricky, since you normally have to widen the fuselage for the air ducts, and the wing roots solution is very elegant for a conversion - that's why I ended up the the 1:100 F-105 wings on my project. And they look SO characteristic that it was IMHO impossible NOT to make a Republic aircraft from the thing...

Not certain if 1:48 wings of a F-105 can be easily obtained or a conversion kit of some kind, but these should fit in size and shape on a Su-22? An F-84F is also an option, as well as a Hawker Hunter?

Somewhere I have seen A-4 air intakes transplanted onto a Su-22 - but IIRC it was just a CG experiment, not true model hardware. But I could imagine that it might work - maybe add some splitter plates, though?

Anyway, a "closed-nose" Su-22 should look awesome - looking forward to the result!

I'd considered F-105 wings but somehow, they just didn't look right. I wanted to retain the characteristic sit of the 22 and,fitting the hefty undercarriage into the 105 wings would have involved more work than I was prepared to do.. The Fitter's wing roots are certainly deep enough to accommodate intakes a la F-105 and, I'd considered building wing intakes but, I figured giving it a nose job would be simpler. Given that the air duct runs down the centre fuselage, no widening would be required anyway.

I've seen the photo you refer to. It looks great. The aircraft used was a 2 seater & it's in USAF Vietnam camouflage. The A4 style intakes look great on it but, again, given the shape of the fuselage in that area, I decided to take the eas(ier) road!

Allan

Father Ennis · July 01, 2013, 05:58:18 PM

You know there is something very familiar about the look of your plane. Something Soviet from the 50/60's maybe

? Great looking build BTW !!! Good choice of markings,too. I can imagine a trio of them scrambled to intercept a phylanx of UFOs over our capital in the 50's early 60's ...