Monday, June 13, 2011

STOVL combat capability over-hyped

We know that the United States Air Force is committed to fielding the conventional runway version of the F-35.

After the start of the Afghanistan war, the head of the USAF stated that he could see a need for the service to split up its F-35 buy between the conventional runway version and the USMC short take-off and vertical landing (STOVL) version.

This idea (which now seems dead) has to be put in context. The goal of the USAF boss was not some STOVL fantasy super-close to the ground troops. It was based on the idea that the USAF could operate out of some shorter runways; knowing the limits of logistics.

This PDF file (click on link it doesn’t right-click, save-as well) is a school study from the USAF war college dated April of 2006. It states that the idea of STOVL for the USAF is a bad one; that even the USMC hasn’t proven the usefulness of STOVL ops with the Harrier and that if one wanted to be truly joint and save money, USAF should buy the U.S. Navy carrier version; the F-35C. It also points out other problems with the F-35B STOVL such as less endurance and range.

The paper is poorly written and full of holes ( I agree with the lack of worth of STOVL). For instance, the author doesn’t really explore the usefulness of the F-35 program. Since the F-35 won’t be able to do anti-access jobs and is too expensive for anything else, the real question is; Does the F-35 provide any value to the USAF? My opinion is, “no”.

In every major conflict involving US ground troops since Operation DESERT STORM, the USMC Harriers have not been unique in their ability to “move forward” and operate “close to the fight”. For example, during DESERT STORM “Hornets based at Shaik Isa utilized the airfield at Jabayl as a FARP [Forward Arming Refueling Point], just as the Harriers did at Tanajib, thus reducing transit time to and from the target area”.
Furthermore, USAF “F16s…generated a tremendous number of sorties while operating from a forward operating location (FOL) at King Khalid Military City (KKMC) in Saudi Arabia, located just 60 miles from the Iraqi border”.
“F-16s operating there were able to exchange their drop-tanks for extra ordnance: KKMC-based missions carried four Mk-84 2,000-pound bombs (double the normal load of two). FOL operations allowed the wing to fly more sorties per day; KKMC missions launched from the…main base in Abu Dhabi to bomb the KTO [Kuwait theater of operations]; landed and rearmed at KKMC for a second sortie to the KTO (which did not require refueling); landed and rearmed at KKMC for a third mission and after attacking the KTO, air refueled to return to Abu Dhabi.”

Like the USMC Harrier, the USAF F-16’s took advantage of a FOL, but the “F-16 carried a larger payload than either the Harrier or the Hornet, and delivered tons of ordnance…with a very small transit and turnaround time”.

Again, nearly ten-years later, during Operation ENDURING FREEDOM (OEF), the USMC Harriers were not alone in their ability to move forward and operate “close to the fight”. In October 2002, a six-airplane detachment of Harriers from Marine Attack Squadron (VMA)-513 set up shop at Bagram, near Kabul, where A-10s had been operating since March of that year.

Later during Operation IRAQI FREEDOM (OIF), Harriers took advantage of a FARP “at An Numaniyah, 60 miles south of Baghdad” but USAF A-10’s also “deployed forward” and operated out of “Tallil Air Base in Iraq”. However, logistics hampered Harrier operations. According to a “Harrier squadron commander…it was a major task keeping such aircraft supplied with jet fuel at that site”. This squadron commander went on to say, “It takes a lot of support and logistics…so we chose to use other platforms”.

Like the Harrier, the F-35B will be a logistics challenge. A number of logistics risks exist with the STOVL variant that do not exist for the other JSF variants, the primary being the vertical lift fan. Although a revolutionary design concept, the reliability and maintainability of the lift fan is still unproven. The lift fan operates on a single shaft that connects to the main engine and spins at a high-rate of speed. According to one study, this lift fan design causes “ added complexity” due to “the need for the clutch to engage and disengage the lift fan”.

Repair of the vertical lift components would very likely call for removing the engine, a traditionally “high repair time task”. Further, the lift fan and swivel nozzle adds to the logistics footprint  especially when forward deployed.

According to one study, “While the JSF designers strive to reduce the complexity of the aircraft systems, the fact remains that the STOVL…will by nature be more difficult to maintain than either corresponding CTOL or [Navy] version”. This conclusion centered on “Naval Post Graduate School [studies] which compare projected component designs for the STOVL JSF to current Harrier design and projected [F-35C] design”.


Anonymous said...

We ought to be more interested in operations from 'lousy' runways than 'short' runways. Crumbling soviet-era concrete like Bagram's old runway or dirt strips. Practical forward fighter logistics will require at least C-130 resupply. We need A-10 style aircraft that can meet that rugged standard (and not be so gold plated that we never have the will to use it as such, a la C-17). What's the F-35B's tolerance to FOD? I suspect it would be better at vacuum cleaning old-Bagram-esque runways than actually taking off from them.

asdf said...

What's the F-35B's tolerance to FOD?

you don't need an A-10 for CAS, as with modern optics you don't need to go that low (or close) to be exposed to enemy fire. and you can quickly do away with the gun with usage of the Griffin missile.
with its 3-5ft (or m, i don't know exactly) lethal radius a single one of them is much better then the inaccurate gun.
ch1466 is kurt aka anon

Bushranger 71 said...

Hi 'Anonymous'. Rudimentary crumbly weak pavement and short airfields of course affect all forms of tactical air support embracing offensive air, airlift fixed wing and helos to varying degrees; 'hoovering', reverse thrust, strong rotorwash being considerations. But I do strongly support your contention that most ADF tactical hardware should be suited for forward base operations.

I am a disciple of Colonel John Boyd, USAF and thus a fan of the F-16 and A-10; also AC-130 and helo gunships, like a Huey II Bushranger version (but not AAH). These types have well proven attributes for forward base operations.

Sorry 'asdf', but your apparent concern regarding ground-fire risk reflects timidity expressed by others in some forums – see my post (about the 35th) on Eric's V-22 Osprey thread. The following extract is from a comprehensive US Army analysis of the Vietnam War:

‘Statistics on relative vulnerability (of helicopters) reveal that out of 1,147 sorties, one aircraft would be hit by enemy fire, one aircraft was shot down per 13,461 sorties, and only one aircraft was shot down and lost per 21,194 sorties. Used properly, the helicopter was not the fragile target some doom-forecasters had predicted.’

No. 9 Squadron RAAF operated Iroquois somewhat differently during 5.5 years of Vietnam involvement flying 237,808 sorties with only 25 aircraft being hit (1:9,512 probability), 3 aircraft shot down (1:79,270) and only 1 lost to ground-fire (1:237,808). Although RPG-style weaponry in particular has improved over the past 40 years, the risk of being hit is still very low depending largely on helo operating techniques.

But let's consider intimate close air support where opposing forces are engaged at around cricket pitch proximity, as was often the case in jungle war-fighting. Safety distance requirements generally preclude application of ordnance any heavier than HE cannon or high density ball ammunition of smaller calibres. HE cannon can be delivered about 35 metres from friendlies with acceptable risk and 7.62mm minigun about 10 metres in necessitous circumstances. AAH would be better armed for intimate close air support with multiple cannon and minigun fits.

Hellfire and maybe Griffin are very good highly expensive weapons for special applications, but are really only cost-effective for use against high value targets. I crawled over much captured Iraqi armour when living in Kuwait post-Gulf War 1 and a substantial proportion had been disabled/destroyed by accurate aircraft cannon fire, but only a few units by missilery. Guided or unguided missilery is a real logistic and maintenance headache (see: 'APACHE'), whereas canned gun ammunition is very easily managed in forward areas.

Historically, some wrongly concluded that guns on aircraft were no longer relevant and they had to be reintroduced – they remain just as relevant in contemporary war-fighting.

Regarding the JSF. Its operational capabilities are at present largely unproven; meanwhile, western military capacities for offensive air operations are shrinking. Far wiser in my view to continue optimising existing assets (where cost-effective) to maintain armed preparedness for unforeseeable military situations.

The Force 2030 notion for the ADF is unrealistic and Australia could benefit if the JSF project founders, forcing a rethink of capability requirements and force structuring. I am much hoping that the F-35 project will fail.

Lorenzano Di Renzo said...

Extremely interesting article. Too bad I haven't been able to download the study. Does anybody has a different link I could get it from?
Eric, do you know on what basis the Air Force decided to give up the acquisition of F35B?


L. Direnzo