Flightline Friday: the incredible Thud

I’ve read both of Ed Rasimus’ books about his two tours of duty in Southeast Asia during the Vietnam War.  He flew one tour in F-105s during Rolling Thunder (April-September 1966), and another in F-4Es during Linebacker I and II (July 1972 – ? 1973).  It makes for more than slightly interesting reading, though I must admit I was dismayed to read that he succumbed to the same collapse in morals in his second tour that were afflicting the entire culture in that timeframe. Enough said.

I have long been enthralled of the Republic F-105 Thunderchief.  In Air Force circles, it is legend, for many reasons.  It was incredibly tough.  Thuds survived battle damage over North Vietnam that would have left a WWII B-17 crew shaking.  One reason it was so tough was because Republic had always built very heavy, strong birds.  Even with water injection increasing takeoff thrust to nearly 27,000 lbs, a heavily loaded Thud in a hot and humid environment like Southeast Asia often needed over 10,000 ft to takeoff.

It was also very capable. I was surprised to learn that Rasimus found the F-105 NASARR R-14A radar far more capable than that in his F-4E (APQ-120), especially in ground attack and terrain avoidance modes.  The F-105 radar was one of the very first with a fair terrain following/avoidance capability.  He generally found the Thud to have better avionics, at least for ground attack, than the F-4E – and aircraft developed over 10 years later. Though, the F-4Es inertial navigation system and vastly improved bombing computer did allow some modes of attack that were unavailable in the Thud and which sometimes – when it worked – made bombing a point target a relative snap.

But it was in the area of flight performance that I found his reminiscences most revealing. I had long read that the needle-like Thud was very fast down low. I have read reports of Thuds topping 800 kts (~930 mph) on the deck after they had dropped their ordinance and were “clean.”  In Rasimus second tour, his main duty especially during the incredibly intensive bombing of Linebacker II (which finally ended the war) was to escort “Wild Weasel” F-105s in attacking SAM sites.  They really nailed a few.  In Wild Weasel, specially equipped F-105Gs would use sensors to detect the presence and location of SAM sites, and operate in conjunction with F-4Es carrying cluster bombs as a hunter-killer team. The Wild Weasels would find the SAM sites and sometimes shoot a missile at them (which rarely worked, back then – all the North Vietnamese had to do was to turn off their SAM radar and the missile would lose lock and fall to the ground), but then they would call in the F-4s to drop their cluster bombs, which really did the trick. They absolutely pasted a few SAM sites.

Anyways, the Phantom did not lack for thrust.  With two J79-GE-10 turbojets making 17,900 lbst each, they actually had about half again as much thrust as the F-105.  But the 105 was much more aerodynamic.  It has been said of the Phantom that it is an object less that with enough thrust you can get even a brick to fly.  The Phantom was a very high drag aircraft and was especially so when carrying ordinance.  So on these SAM suppression missions, when the F-4s would be operating with the F-105s (generally a few thousand feet above and behind the Thuds), Rasimus often found he had to engage afterburner to keep up with the Thuds traipsing along at 600+ kts in military power.  That with two drop tanks and a couple of missiles hanging on the rails.  The Phantom, with ordinance, wanted to cruise at about 450 kts, while the Thud wanted to be at more like 550.  That makes a huge difference in a country that was wallpapered with not just SAMs, which were exciting but could be beaten, but also with every caliber of gun from pea shooters up to 100 mm radar guided cannon.  Even with radar guided AAA, it is pretty hard to hit an aircraft jinking and diving at over 600 kts, but at 450 hit probabilities go up tremendously.

Unfortunately, due to incredibly stupid rules of engagement that literally had aircraft attacking the same often worthless target, coming in at the same time of day and from the same approach vectors, day after day, a lot of Thuds were lost.  In fact, over the course of the war, 395 of the 833 Thuds built were lost.  The Air Force wanted to build a lot more Thuds, they preferred the Thud to the Phantom for ground attack, but McNamara insisted all the services use the same fighter (which led to the F-111, and now, the F-35, debacles), and so F-105 production was terminated in 1961.  It’s a shame in some respects, because it is  likely a goodly number of aircrew would not have been lost had they been in F-105s rather than F-4s.  Don’t get me wrong, I love the Phantom and am not knocking it at all, it was an is a heckuva plane, but it wasn’t a Thud.

Rasimus’ unit, 421st TFS, Korat RTAFB, 1966. Could be Raz himself, but unlikely

There is a dirty joke in the tail codes. SH means Sierra Hotel in the phonetic alphabet, but also means S— Hot, a common expression used during Vietnam for a stellar performance. I think this tail code was used at Takhli late in the war. The wing is declaring their stellar qualities.

My man Karl Richter. This is his statue at the Air Force Academy. He deserves it.

Why not some more Richter photos. He deserves it, Mr. 200+ missions:

Alright, there might be a bit of a man crush going on.  But Richter was a hoss.