HABS (not LABS) nuclear bombing with US fighters?

[Rob de Bie]

I'm researching the weapons used by RNLAF F-84Fs (see photos below), and looked into the delivery methods of the nuclear weapon. The USAF trained RNLAF pilots in two techniques: LABS (Low Altitude Bombing System) and HABS (High Altitude Bombing System). Most RNLAF strike F-84F training missions involved two HABS and two LABS deliveries.

 

I guess LABS is well know: make a half loop (Immelmann), and drop the weapon at either ~45 degrees climb angle for a toss delivery, 90 degrees for a 'vertical' delivery, or ~110 degrees for an 'over the shoulder' delivery. All three methods result in the weapon having a say 40 second flight time, allowing the attacked to get away from the blast.

 

HABS involves a dive from 23k ft to ~10k ft, 60 degrees angle, with weapon release at the end of the stable 60 degree dive. I don't see yet how that creates safety for the attacker.

 

So far I haven't found HABS being mentioned for any other fighter than the F-84F. Does anyone know of its use for any other fighter?

 

Rob

 

 

[Tailspin Turtle]

HABS, probably by another name, was the standard delivery for U.S. Navy carrier-based aircraft carrying the Mk 7 and Mk 8 prior to the development of LABS. It may have involved some retardation on the nukes to provide a little more separation from instant sunshine but the theory was the escape speed generated by the dive and the ability to quickly get low into terrain masking would make the maneuver survivable. The Mk 8 was also intended as a submarine pen buster, so it would penetrate some depth into the ground or concrete before detonating.

[Rob de Bie]

On 2/22/2025 at 5:02 PM, Tailspin Turtle said:

HABS, probably by another name, was the standard delivery for U.S. Navy carrier-based aircraft carrying the Mk 7 and Mk 8 prior to the development of LABS. It may have involved some retardation on the nukes to provide a little more separation from instant sunshine but the theory was the escape speed generated by the dive and the ability to quickly get low into terrain masking would make the maneuver survivable. The Mk 8 was also intended as a submarine pen buster, so it would penetrate some depth into the ground or concrete before detonating.

 

Tommy, many thanks for responding. I had no idea about Navy delivery techniques, I realize now.

 

Here's a graph I made of the information that I found in an old USAF/RNLAF HABS-LABS training document. Does that match the pattern you describe?

 

Dutch F-84Fs used the B28, unretarded as far as I know. LABS was done with unretarded weapons, and the practice bombs were always Mk76 'slicks'. Those wouldn't be suitable to practice 'retarded HABS' with, and most missions had two HABS and two LABS deliveries.

 

That leaves the question what protection HABS offered to the attacking pilot. LABS leaves a lot more time (around 40 seconds) to escape from the blast.

 

 

Rob

Edited February 23, 2025 by Rob de Bie

[Tailspin Turtle]

Rob, thanks for that. The first Mk 7s had dive brakes for retardation (however, I don't think I'd level out as depicted in your illustration: I'd keep diving, albeit at a shallower angle, until I had to pull out or hit the trees). I vaguely remember that the release altitude was 10,000 feet: I'll see if I can find documentation. The Mk 8 had a frangible nose cap over a blunt spiked nose as it was intended to penetrate some distance into the ground and/or concrete before detonating (it was the very inefficient gun-type device that would survive that shock). That would slow it down and result in somewhat less effect laterally, certainly relative to an air burst.

[Rob de Bie]

Tommy, thanks for the additional details. I must admit that I don't know many details of the B28 as used by RNLAF F-84Fs.

 

I consulted the Wiki page (ahum) and it says the parachute-retarded B28RE was suitable for laydown delivery, that including a (retarded) impact. But I still think the not-retarded B28EX was the weapon of the RNLAF F-84F, as its delivery was simulated with slick Mk76s. I guess a not-retarded impact was out of the question.

 

I hope to interview a few pilots about the subject, but generally they are reluctant to talk about it. Still.

 

Rob

[Tailspin Turtle]

1 hour ago, Rob de Bie said:

Tommy, thanks for the additional details. I must admit that I don't know many details of the B28 as used by RNLAF F-84Fs.

 

I consulted the Wiki page (ahum) and it says the parachute-retarded B28RE was suitable for laydown delivery, that including a (retarded) impact. But I still think the not-retarded B28EX was the weapon of the RNLAF F-84F, as its delivery was simulated with slick Mk76s. I guess a not-retarded impact was out of the question.

 

I hope to interview a few pilots about the subject, but generally they are reluctant to talk about it. Still.

 

Rob

Literally back-of-the-envelope crude calculation, in 16 seconds at 532 knots TAS, the jet would be about 24 nm away and opening the range at 1.5 nm per second. Seems doable.

[Hajo L.]

Are you sure that 532 knots are meaning a speed of 1,5nm per second(!!)? Because if you take 1 second x 60 (to get to minutes), than x 60 again (to get to hours), you'll end up with 5400nm per hour.... 😉

 

Hypersonics weren't invented back then....

 

 

HAJO

[habu2]

My back of envelope says 

532 kts ~= 612 mph

/60 = 10.2 statute miles/min

/60 = 0.17 statute miles/sec

~= 0.148 nautical miles/sec

[Tailspin Turtle]

In my defense, I hadn't had my coffee yet. Anyway 2.4 nm away and low and opening might work if the metal on your control surfaces is fairly thick and they are painted white.

[Hajo L.]

A lot of funny things wouldn't have happened if we had coffee in time.... 😉

 

 

HAJO

[Winnie]

8.86 NM a minute at 532 knots. Calculated on my trusty E-6B

[Murph]

     FWIW, most USAF fighter pilots I flew with ditched the "whiz wheel" once they graduated pilot training.  After that we would break planned speeds down to miles per minute, fuel flow down to pounds per minute, and plan routes based on multiples of six.  That meant routes were typically planned for a groundspeed of 300, 360, or 420 mph (aka 5, 6, or 7 miles per minute).  Heavy bombers with a Nav or two on board probably varied from that, but the single seat fighter tried to keep it as simple as possible inflight.  As you would expect, this preflight planning is all pretty much done on a computer now. In the graph cited above the aircraft is basically doing 9 miles a minute at release and during the escape maneuver, while the bomb will take 15 seconds to detonate (in a single seat aircraft always round to easily divisible numbers).  That would give a separation of 2.25 miles from the detonation point using fighter pilot math.  Dive passes were predicated on hitting a certain altitude, at a certain speed, at a certain dive angle with a specified mil depression on the gunsight "pipper" to maximize accuracy for unguided weapons.  Once they came up with the CCIP and CCRP, this got WAY easier.  

     I was fortunate enough to never have anything to do with nukes, but most pilots I talked to who sat Victor Alert didn't expect to survive the mission.  

 

Regards,

Murph