Saturday, September 19, 2009

Arming the new Light Strike Aircraft


A couple of days ago I wrote about the USAF's proposed new Light Strike Aircraft, and examined the proposed Hawker Beechcraft AT-6, currently under development, and the Embraer EMB-314 Super Tucano, as potential solutions to this requirement.

Several readers e-mailed me with rather negative comments about such aircraft. A common thread was that they didn't carry enough ordnance to provide adequate support to troops in contact. As one correspondent pointed out:

In Vietnam, the Douglas A-1 Skyraider [which we examined in depth in Weekend Wings #31] carried up to 8,000 pounds of ordnance on up to 15 hardpoints beneath the fuselage and wings. The proposed AT-6 will have only six underwing hardpoints, plus (presumably) one beneath the fuselage. It's unlikely to carry more ordnance than the Super Tucano, which has a payload less than half the Skyraider's. That's not enough. Neither aircraft can carry enough weapons to get the job done.


I can understand my correspondents' concerns, but I submit they're misplaced. They haven't taken into account the development of weapons over the past couple of decades, which have revolutionized effectiveness and efficiency. Let's examine just a few of the weapons such a Light Strike Aircraft could employ.


1. BOMBS

The old-fashioned 'dumb bombs' in 500lb., 1,000lb. and 2,000lb. weights were ubiquitous in Vietnam - and highly wasteful. Tens of thousands of bombs were dropped on empty jungle in what disgruntled pilots called 'making matchsticks'. Given their inability to identify and locate the target precisely, pilots had to drop multiple bombs over an area to neutralize whatever threat lay within it. Even with so profligate an expenditure of ammunition, they weren't always successful.

'Smart' bombs made their first appearance towards the end of the Vietnam war, and came to prominence in Operation Desert Storm. Since then, they've largely taken over most strike roles. The same bombs as were used in Vietnam are employed, but are now fitted with guidance systems and winglets, so that they can glide to a precisely-designated point (either under Global Positioning System (GPS) guidance or directed by a laser target designation system) and destroy it. One 'smart' bomb can now destroy a target that might have survived twenty to thirty 'dumb' bombs in the past.

Given this increased accuracy, it didn't take long for someone to work out that the size of the bomb could now be tailored to the desired result. It didn't make much sense to drop a 2,000 pound bomb on a group of infantry in a trench. Sure, it'd dispose of them, but much of the blast would be wasted. A 500lb. weapon would do the job just as efficiently. In the same way, a tank might be destroyed by a 500lb. bomb, but that was still 'too much gun'. A bomb half the size would be adequate for the job, provided it could be placed accurately on target.

This has led to the development of the newest generation of 'smart bombs', the so-called Small Diameter Bomb (SDB).




This 250lb. weapon is much smaller than earlier bombs, but just as lethal, since it can be guided to its target by either GPS signals or a laser designator beam. No less than four SDB's can be carried on a rack in the space formerly required for a single 1,000lb. or 2,000lb. bomb.



Four rack-mounted SDB's loaded on a single pylon beneath an F-15E Strike Eagle



The SDB's fuse can be set to detonate above ground, producing a shrapnel effect; on impact, producing a surface blast; or at a preset interval after impact, allowing it to penetrate deep into the earth, or through reinforced concrete defenses, before exploding. The two pictures below show an SDB being tested against a reinforced concrete aircraft bunker. It penetrates all the way through the protective bunker before exploding.






Some may criticise the SDB for being 'only' 250lb in weight, but I don't think that aircraft's going to be flying anywhere after that little encounter!

Here's a video clip of the SDB, going into more detail about how it works. I apologize in advance for the breathless "oh-gee-whiz!" commentary, but that's modern television for you. If the announcers would just shut up and let the designers and engineers tell the story, it'd be much better!





Two new versions of the SDB are under development, and will be deployed in the near future. One, referred to in the video clip, will have a multi-mode seeker head, enabling it to acquire and attack moving targets. The second, the so-called Focused Lethality Munition (FLM), has a carbon-fiber casing and multi-stage explosive warhead, designed to minimize shrapnel and collateral damage, and focus the entire blast on the specific target. Here's a video clip of an early test of the FLM.





As mentioned earlier, an aircraft weapon station that previously carried a single large bomb can now carry up to four SDB's, quadrupling its effective bomb load. That's going to be very useful for the proposed Light Strike Aircraft, with its lower payload.


2. ROCKETS.

Unguided rockets have been a staple of close air support since the later years of World War II. The US has employed 2.75" rockets of various types, the current iteration being known as Hydra 70. They're mounted in 7-tube M260 or 19-tube M261 launchers on US Army attack helicopters, such as this M261 mounted on an AH-64 Apache. (The rockets shown are of different lengths, due to different warheads fitted to them.)




The main problem with these rockets has been their lack of guidance. A salvo of many rockets has typically been required to destroy a target, and the tendency of some rockets to 'wander' off-course has caused more than a few gray hairs among friendly forces on the ground!

As a result, and given the advances in weapons guidance systems, a large number of projects are under way to add guidance systems to the 2.75" rocket, making it a precision munition in its own right. Among the current programs are the Advanced Precision Kill Weapons System (APKWS), currently being run by the US Navy; the CRV-7 Rocket Weapon System; the Direct Attack Guided Rocket (DAGR); the Guided Advanced Tactical Rocket - Laser (GATR-L); the Laser Guided Rocket (LGR); the Low-Cost Guided Imaging Rocket; and the Roketsan Cirit. This is far from a US-only effort: nations such as Israel, South Korea and Turkey are involved in some of these projects, and it's a virtual certainty that other nations (including Russia and China) are engaged in similar work.

We can't possibly look at all these programs in detail in a short blog post, but they all involve fitting a guidance kit onto a standard 2.75" rocket. Let's look at one in detail, the Direct Attack Guided Rocket (DAGR) (shown below), being developed by Lockheed Martin.




Lockheed are developing an innovative 4-round launcher for the DAGR (shown below), each of which can fit onto the same bracket used to launch a single AGM-114 Hellfire anti-tank missile. Thus, a 4-round Hellfire launcher, as illustrated, can handle up to 16 DAGR rounds, or a mixture of DAGR and Hellfire weapons.




DAGR has already been successfully tested on the ground and aboard two models of helicopter. Here's a video clip showing early ground tests. Note the exceptionally good accuracy obtained against targets.





DAGR and similar rockets will probably also be able to be launched from standard rocket pods. In anticipation of these being used on aircraft faster than typical attack helicopters (such as the proposed Light Strike Aircraft), at least one company is developing streamlined rocket pods that will cause less drag at higher air speeds.

With such accurate rockets, the Light Strike Aircraft will be able to hit multiple targets with one or two rockets each, rather than the 'spray-and-pray' technique used with unguided rockets. This will make its payload far more effective, and - as with the SDB - it'll be able to deal with more targets for a given payload than was previously the case.


3. MISSILES.

It's a virtual certainty that the Light Strike Aircraft will be able to launch guided missiles such as the AGM-114 Hellfire and similar weapons, and perhaps even the much larger AGM-65 Maverick. However, these are not ideal close-air-support weapons. They're great at killing tanks, or taking out hardened structures: but for troops in combat, they're often too big for the job that needs doing (just as 500lb. or 1,000lb. bombs are 'overkill' for many targets). I'd expect the Light Strike Aircraft to carry relatively few such weapons, reserving them for important targets, while using guided rockets (as described above) for less resistant targets. It may also be that new versions of the SDB coming into service will render such missiles redundant in the close air support role.



4. CANNON AND MACHINE-GUNS

Some believe that a ground-attack and close-air-support aircraft must necessarily have a heavy gun armament, in order to strafe enemy positions. This is certainly useful, but with the advent of precision guided weapons, I suggest it's less important than in times past. The Embraer Super Tucano has two .50-caliber machine-guns in the wings. The AT-6, as I understand it, won't have integral guns in the wings, but can carry a cannon or machine-gun in a pod on a weapons station beneath the wing or fuselage. This would also allow for a heavier weapon than a machine-gun to be fitted, without worrying about internal space constraints.



5. OTHER WEAPONS.

Perhaps one of the most interesting developments in recent years is that remotely-fired and -controlled weapons are now entering the scene. These can be pre-positioned, or trucked to a safe location by transports, and called upon when the warfighters need them.

Two examples have so far received publicity. One is the Non-Line-Of-Sight Launch System, being developed for US forces by Lockheed Martin and Raytheon in partnership. It's a box known as a Container Launch Unit (CLU), holding 15 missiles with a range of dozens of miles. The CLU can be transported aboard a truck, and fired from there, or lowered to the ground for use. Here's a picture of a missile being fired from a truck-borne CLU.




Two missile types are under development for use in the CLU. The Precision Attack Munition will have a range of about 25 miles, and have a guidance system using GPS and/or laser designation and/or autonomous infrared imaging. The Loitering Attack Munition will have a longer range of over 40 miles, and will fly to a pre-designated area and loiter overhead for up to 30 minutes while seeking targets.

Here's a video of the NLOS-LS. Again, apologies for the breathless excitement of the commentator!





Israel has developed a similar system, called Jumper (shown below). It has eight missiles in its container, each with a range of over 30 miles.




It's highly likely that the USAF's Light Strike Aircraft will be equipped to call on such missiles to attack targets it designates. The missiles can be simply 'dumped' in a convenient location (perhaps a hilltop firebase, or something like that) and left there to be activated when needed. They don't need a crew, or local intervention to fire them.


So, the Light Strike Aircraft will have a considerable variety of munitions at its disposal, either carrying them itself, or able to call on them from outside sources. Even with only six under-wing and one under-fuselage hardpoints, it could carry up to eight SDB's, plus up to eight DAGR's (or even more if higher-capacity rocket pods are developed), a couple of Hellfire missiles, a gun pod, and a targeting pod. That's an awful lot of firepower!

It might not even need to use its own weapons. Let's take an example of a US patrol ambushed by enemy forces in the mountains of Afghanistan. Due to the mountains interfering with radio communications, the patrol can't call on systems like the NLOS-LS for itself. It could begin its counterattack by using its own miniature UAV, such as (for example) the RQ-11 Raven currently in service (shown below), to precisely locate enemy positions.




While doing this, the patrol would call for air support. A Light Strike Aircraft (or more than one), loitering in the area or on call at a nearby base, would speed to their location. On the way, the aircraft would receive information from the UAV about enemy positions. On arriving overhead, the aircraft would verify this information, using its more comprehensive electronic systems, and either establish the GPS co-ordinates of the targets or stand by to designate them with its laser targeting pod. It would then, from its higher altitude (which eliminates the problem of interference from intervening mountains), transmit instructions to an NLOS-LS CLU, up to 20 miles away or more, to fire a number of missiles. Those missiles would transit to the engagement area, take their targeting data from the aircraft, and dive onto the targets, destroying them. The aircraft might never need to use its own weapons or descend to within range of enemy fire.

So, with the greatest of respect to my correspondents, I think that the close-air-support scenario has changed so much since the days of Vietnam and the Skyraider that the lesser payload capacity of aircraft such as the AT-6 or Super Tucano is no longer a drawback. On the contrary - if one tried to load a Skyraider to full payload capacity with modern, compact weapons, one might come back after most missions with more than half the ordnance unexpended!

Peter

14 comments:

LL said...

With respect.

The A-1 "Sandy" was and remains one hell of an aircraft in terms of the damage the aircraft can sustain and keep flying. It also has the ability to put heavy gunfire support down, providing that it's a requirement the military is interested in. It's carrier friendly and with enhanced avionics and low light/no light capability it could be an impressive answer to the problem.

One of the benefits of the Sandy was that it remained on station and had a long loiter time. They carried a lot of fuel and had the under-wing hard points to carry 4 drop tanks which meant the ship could hang for a long - long time and still carry an impressive load-out of munitions.

Call me nostalgic. Sometimes when we reinvent the wheel we go back to where we started...

Glenn B said...

That is some scary stuff. I'd hate to see it coming at me, and am happy we have it to send at them.autast

Anonymous said...

So which would be better; a plane that could carry 8,000 pounds of smart bombs(32/250#) or one that carries less than half that many? Not to mention newer engines options for an updated Spad.

And if you are going to end up using one bomb(or missile per terrorist( as seems to be the norm now), you better be able to carry a s**tload of bombs.
emdfl

PeterT said...

Does anyone remember just how big the Sandy was? That sucker was huge. I'll bet you could carry at least 2 if not 3 at-6's in the same deck space as a Sandy. Don't get me wrong, I thought the Sandy was really great, but time and technology move on!

PeterT

Unknown said...

You are describing two different modes of operating. One up high dropping guided bombs, and surveying with expensive electronics. The other down low and firing missiles and guns much like an Apache helicopter. The up high profile is new and gives the chance for UAV like support at a tactical level, which can be a great benefit to front line troops.

However I think that the reason a smaller plane can be used is because the number of troops involved by the enemy is much smaller. The AT-6 is for guerrilla sized conflicts with all that implies in terms number of targets, complete of air superiority etc.

Anonymous said...

Here is one thing to consider: A 5-round 70mm rocket pod, a 250-pound SDB, and a Hellfire missile, can all be loaded by hand. Maverick cannot, its too heavy. If the guys on the ground can do everything they need to do without an MJ and ground firm enough to support it then they can operate this new aircraft from a much wider variety of surfaces.

Great article, Peter. I never met anything with yellow stripes I didn't like.

Jim

PS - The USAF Air Weapons Museum at Eglin AFB is a really neat trip if you can get there.

LL said...

I think you could re-tool the engine on the Sandy or build a robust platform of that sort that has the legs to stay on station. It's not only about the ordnance, it's about loiter time. That's why the B-52's were so effective as essentially airborne artillery. They could remain on station until called up by the guys on the ground.

JMO.

Rick R. said...

Precision guided munitions are WONDEFUL, when the enemy consists of discrete, hardened point targets.

But what about when teh enemy consists of soft, diffuse, hard to identify targets, like troops in the bush? Or is massing for an attack?

Such as we faced in WWII.

Such as we faced in Korea.

Such as the Soviets faced in Afghanistan.

Such as Iran and Iraq faced during the firsrt Gulf War (you know, the decade long bloodbath before DESERT STORM).

Such as we have faced in Afghanistan.

Such as we WILL have to face in (for instance) Korea, should full war break out, but remain below the nuclear threshold.

Sometimes, you need cheap, dumb weapons for area effect -- not becuase you cannot hit a specific target, but becuase there is no specific point target worthy of a bomb.

That calls for a bomb truck that can carry enough weapons to hit a large area -- even if we stipulate cliuster munitions, it takes a lot of ordnance to "sterilize" a patch of ground that equates to a company that's been spread out.

Likewise the advantage of the A1E's 20mm cannon. (Likely today, you would use a 25mm Bushmaster or a 30mm Bushmaster II in lieu of a bunch of wing mounted 20mm.) 25mm and 30mm projos can eliminate large numbers of soft and medium-hard targets from a significantly farther distance (well beyond any realistic gorund fire, short of dedicated radar aimed ADA SPG or IR seeking MANPADS), especially given teh tech advantage we can incorportae in the FCS these days.

And then there's the fact that a larger aircraft that takes more damage and can loiter longer is more of a force multiplier, even if it only had the same payload as the smaller bird.

It's always a mistake to prepare to fight teh last war at teh expence of other threats.

it's even MORE of a mistake to think that we can abandon old techniques, becuase in new scenarios there are new techniques that work better. Because sometimes the old scenarios come back.

Anonymous said...

Thing is, these aren't a replacement for the big sticks, rather the right tool for a specific set of jobs.

Jim

Fly To Your Dreams said...

I'd argue that the main reason you don't see any proposals for a new A-1 Skyraider/A-10 Thunderbolt II is cost. While the proven turboprop engines to haul such an aircraft exist, I think it'd have to be an entirely new airframe and production line. Even for a relatively "simple" aircraft, that gets pretty expensive, and I haven't read anywhere where there's a forecast demand for enough of these aircraft to cover that expense.

The beauty of the AT-6 or Super Tucano is that they're based off existing production lines. Sure there are aspects that are specific to the attack versions, but much of the costly development work on the airframe is done, and I'm guessing that there's a high parts commonality between the attack and trainer versions, at least while on the production line.

Tim D said...

I guess they called the DAGR a rocket just to have a cool acronym. As far as I recall the military definition of a rocket is that it is unguided. I guess DAGM just isn't as cool.

Anonymous said...

I'd expect most of the airframe to be the same. The most expensive systems on the aircraft are the electronics, the engine/prop, and the ejection seat(s). The electronics are going to likely be fairly similar to what is in use in the Reaper UAV, but the seat is done already and PWC has had the PT6 figured out for ages. So it shouldn't be too steep a learning curve to get this thing working.

Jim

Byron Hukee said...

Interesting read, and I agree with most all. A correction however with regard to the A-1 "Sandy". We who flew the aircraft [Skyraider] NEVER referred to the aircraft as the Sandy.... Sandy was the call sign we used when were performing the Search and Rescue mission. The aircraft was referred to as the Spad or Super Spad, but never the Sandy.

SpadGuy

M&S said...

An A-UAV runs around 900 dollars an hour for a Rotax engine Predator and 3,600 dollars per hour for a TPE331 Reaper. That's two Hellfire vs. four plus a GBU-12 or 58. Vs. Eight SDB at 42,300 dollars an hour for an F-35.
What isn't accounted for here is that TIME is everything. You have to be able to sustain multiple CAPs right near the friendly unit, or it's mission route to sanitize and rapidly respond.
And drone which can stay on station 20-30hrs (Predator) or 15-20hrs (Reaper/Reaper-ER) can thus dedicate a whole flightline to CAS Stacks on a 'one per day or until the munitions run out'. Compared to a manned aircraft with maybe 4-6hrs on station before the pilot starts to bleed competence from sitting on that rock hard seat.
That's a LOT of coverage with the MCS basically telling the UAV to fly a pattern until the operator gets back to it, taking pictures.
CCD or Coherent Change Detection then lets you cue the operator when a given area shows a pixel change in an image. Computers love this math-heavy stuff. Guys flying NTISR with 8X8 MFDs? Not so much.
IF you can preempt the threat, the first hair, teeth and eyeballs engagement which blows up the guy with a satphone or a heavy weapon ends the hero complex in the rest. And you basically tail a few back to X location for the SOF to go have a chat with.
By the time you are reactive to a casualty in progress, you are talking body bags and fast ambulance.
An Armed UAV cannot point it's nose at a target from high altitude.
Such is actually good thing since pointing your nose at a target entails a roundout through the trashfire floor and possible engagement.
While UAV VNe limits remove the 10,000 dollars per round guided rockets from the cheap end of PGMs, other systems, like Griffin and Fury and even late model Hellfires have 270` engagement around the airframe velocity vector and so can engage while remaining ground track oblique to the target.
Griffin and particularly Fury are also small enough (35-50lbs) to be stacked in tandem, beneath fuel tanks. And this makes them pass-dense relative to their parasite drag performance penalties.