The avionics in both aircraft represent the latest technology of their respective periods. The F-105's ASG-19 Thunderstick I/II system was tightly integrated with the NASARR multimode radar, as is the JSF's ICP package and APG-81 radar. Both radars are designs biased toward air-ground modes, but with respectable air-intercept capabilities for their periods.

The definitive F-105D, of which only 610 were built by 1964 due to higher than hoped for costs, could carry up to 2,500 lb in its internal bomb bay, and external stores on two 3,000 lb inboard pylons, two 3,000 lb outboard pylons and a 4,500 lb centreline pylon, for a total of 12,000 lb. The JSF carries a 2,500 lb guided bomb in either fuselage bay, up to 5,000 lb on a pair of inboard pylons, and 2,500 lb on a pair of outboard main pylons, with a 1,000 lb centreline pylon.

The F-105D fleet was thrown into the meatgrinder of the NVA air defence system, then the most formidable in existence as the SovBloc pushed their latest SAMs, radars and MiG-21 Fishbeds into the theatre. Between 1965 and 1970 no less than 334 fell to enemy defences - 312 to SAM/AAA - not a bad figure in terms of sorties flown and the density of defences in theatre. Despite the bad press attached to the F-105, it was a rugged high performance aircraft capable of taking a lot of punishment.

The typical configuration for strike sorties was a payload of 6 to 8 750 lb M117 dumb bombs (4,500 lb to 6,000 lb), with two external 450 USG tanks. For shorter ranging CAS/BAI tasks, up to 12 M117 or 9,000 lb were carried. These payloads are very similar to the nominal internal/external payloads of the JSF. Typical fuel for an F-105D using internal tanks, a bomb bay tank and two 450 USG tanks was 16,000 lb - very close to the internal fuel of a JSF.

Early F-105 sorties were flown in a self escort configuration, armed with an internal 20 mm gun and an external AIM-9B missile, paired with an EWSP pod, on outboard pylons. The NVAF quickly learned that early engagement of the F-105 strike packages forced them to jettison bombs to achieve viable performance to defend themselves or evade attack, and very early the F-105s were supported by F-4C Phantom CAPs to keep the MiGs clear of the strike packages. A later tactic saw F-4C/D Phantoms interspersed with F-105s to effect defacto escort support. Most sources claim 22 F-105s lost to MiGs for 27.5 MiGs shot down by the F-105s, or an exchange rate of 1.25:1 in close air combat.

The F-105 experience presents an interesting case study of self escorting strike fighter operations, and the utility of a strike optimised tactical fighter in air combat. Two factors make this experience important. The F-105D/F and MiG-21 Fishbed had defacto parity in radar/missile performance with the MiG doing better in turn/climb performance, and the extended duration of the campaign made for a large number of statistically valuable repeat engagements.

This is especially relevant for the Australian DoD which intends to fly self escorted F/A-18As and later JSFs into a Sukhoi Su-30 rich regional environment. For the non-stealthy F/A-18A the reality is that an inbound Sukhoi will force an F/A-18A to jettison stores to achieve viable air combat performance to even survive the engagement - unlike an F-105D evading a MiG-21PF, the F/A-18 family does not have a speed/endurance advantage to play against the Sukhoi. For the JSF, which has roughly parity in radar performance against better Su-30 variants, and parity in energy performance against older Su-27SK configurations, it puts all of the survivability eggs into the stealth basket.

There is another interesting parallel in the F-105/F-4 experience, which is that the F-4 had a significant advantage in radar/missile range and energy performance. This parallels the superior stealth, radar, missile kinematic and energy performance advantages held by the F-22A, intended to escort the JSF in US Air Force service.

While the JSF and F-105 are separated by almost half a century in technology, they occupy almost identical niches in size and intended role optimisations. The F-105 was clearly an outstanding success in its primary role of strike/interdiction and close support, but was much less successful in air combat. The lesson in this for future JSF users is a simple one - the JSF is likely to be highly effective in its primary battlefield interdiction / close air support role but less likely to be successful in air combat, as its basic aerodynamic performance is close to parity with the most likely adversary types - advanced Su-30 variants. The decisive factor for the JSF in this game will be its limited stealth performance against the full spectrum of opposing radar systems, especially long range lower band surveillance radars used to guide Sukhoi intercepts.

The Australian DoD's idea of using the reduced stealth export JSF as an F-22A substitute courageously defies historical experience in the use of strike optimised tactical fighters in air combat. It will inevitably attract criticism of the JSF's limited air combat performance rather than criticism of the intention to use the JSF outside of its design optimal roles. The JSF is no more an F-22A, than the F-105D was an F-4C.