Tag Archives: aircraft

Parvusimperator Reviews the F-22 Raptor

No fighter discussion would be complete without mentioning this one, even if it’s technically not available for the procurement games.

To understand the F-22, we should first look at the ATF, or the state of military aviation in the ’80s. The core of the USAF was the F-15 and the F-16. These were great fighters, but the Soviets had counters, namely the Su-27 and the MiG-29, which were at least the equals of the American fighters. In the maneuverability area, they might even be considered a bit ahead.

American doctrine was heavily invested in air superiority, and the USAF was always looking for the next big thing, so they put out a design concept for the ATF. It was to fly faster and higher than other fighters. Or, more precisely, to cruise higher. Speed is good, since speed is energy that can be converted into maneuvers. Energy is life. But supersonic speed meant afterburners, which burned fuel rapidly. So most fighters couldn’t sustain supersonic speeds for very long. The USAF’s idea was to use new engine technology to push the envelope of cruise speed, not maximum speed. The resulting fighter would not be faster than the Eagle, but it would be able to maintain supersonic speeds without lighting its afterburners (to “supercruise”). These engines would be designed to work at higher altitudes, because altitude can be converted into energy. Energy is life. Energy is winning.

Of course, there were secret projects in the works too, and so the USAF added stealth requirements. Stealth demanded careful shaping, special skin, and internal carriage of weapons. This helped the supercruise, since it reduced drag. A protracted development period due to the end of the cold war, and a competition between the Lockheed and Northrop Grumman entries eventually resulted in the F-22 we know today.

The F-22 is the king of the skies. Full stop. There is no better aircraft at aerial combat. None. Fighting with a Raptor really, really sucks. The Raptor has a massive, powerful, highly advanced, low-probability of intercept radar, and the obvious stealth features. So it’s going to see you first. And because it cruises at mach 1.2-1.4 at a higher altitude than you, the Raptor has the energy to decline any engagement it pleases, or dictate the range as it pleases.

If the Raptor chooses to engage BVR, as we’ve mentioned it’s going to get the first shot. It sees you first. It gets to position favorably. Plus, if you’ll recall, it’s flying higher and faster than you. So its missiles get that much more energy, because they start from a supersonic platform, and get a gravity assist as they dive down. Which is a great recipe for an intensely frustrating exercise. And by ‘exercise’, I mean ‘simulation of being smote by an angry god’.

But that’s BVR. The Raptor owns BVR. What if we force the merge and go to WVR? Probably by stipulating in the exercise rules that it’s a WVR fight, but still. Well, here go some of the advantages, though it’s still a massive pain to acquire a lock on the Raptor. At least you can see it. And you can engage with IR seekers, but not super well. Everybody dies in WVR. The Raptor is no exception. But it has the best aerodynamics of any fighter around, with a very high thrust/weight ratio and very low wing loading. It also has thrust vectoring. So even in WVR engagements, the Raptor is a winner more often than everybody else. It’s kill to death ratio at Red Flag is hilariously lopsided, and that’s against pilots who dogfight for a living.

If you’re thinking this is quite gushy, and excessively positive, you’d be right. I love this thing. But it’s not tops at everything. The internal weapons bays are somewhat limiting. The Raptor was designed around a warload of six AMRAAMs and two Sidewinders internally. This isn’t a bad loadout, though it could be bigger. However, those bays are not very deep. So the F-22 can’t carry much in the way of bombs. And it can’t carry any bombs that are all that big. The F-35 can’t carry many bombs, but it can carry two of just about any air to ground weapon you please. The F-22 is limited to bombs of 1,000 lbs or less, and that size class also rules out most standoff weapons. Plus, it only recently got ground-oriented radar modes. Ground attack is not its thing. Though the USAF is trying, and has made special small GPS-guided glide bombs so the Raptor can bomb more stuff.

Oh, and it’s out of production. Even when it was in production, it was super expensive. You could theoretically restart the production line, but that would cost a whole bunch of money. And the USAF only bought 187, which isn’t a lot. And there are have been issues with the onboard oxygen generating system, which have restricted that flight envelope. Those should be fixed by now.

So it’s an expensive, gold-plated, air-superiority fighter with gimped ground attack in a world of strike operations. Would we buy it?

Well, we can’t. Production lines were closed in 2011. Sorry. Blame Rumsfeld, not me.

Feels like a cop-out, doesn’t it? Okay, fine. Suppose they got their act together and started making them again. Raptors rolling off the production lines. Would we buy them?

Well, we still can’t. Even if the production lines were reopened, there’s a pesky act of Congress in the way. Really. There’s a law in the United States that says Thou Shalt Not Export the F-22. Even to one of America’s favorite and closest allies, like Japan or Australia or Israel. No Raptors for you.

Sigh.

Okay, that’s another cop-out, right? I’m still avoiding the question. Fine, fine. Remove both pesky intrusions of reality. Would. We. Buy. One?

We’d need a price, right? Well, let’s be awful and take the figure from an offhand quote of an Israeli Air Force general of $200 million, rather than the much more favorable wiki flyaway cost of $150 million. So. 200 million dollars a copy. Would we buy?

Hell fucking yeah, we’d buy.

Did you really think I’d say no to the greatest aerial combatant of all time? Are you mad?
We’d be all over this, if the above conditions were met. Even at $200 million. It’s got Wunderwaffe-class awesomeness. It’s also an absolutely beautiful fighter. It looks right. It is right.

Since this is a game, you might be thinking I should try to trade Fishbreath something so we can both skirt our self-imposed rules a little. He’d never go for it though. He doesn’t like spendy wunderwaffe.

Author’s Notes: This review was not sponsored or paid for in any way by Lockheed Martin, the Fighter Mafia, or members of the United States Air Force.

Fishbreath Flies: DCS AJS 37 Viggen Review

Leatherneck Simulations is at it again: a 1970s aircraft modeled in loving detail. Once more, we get a plane which has virtues beyond accuracy. Leatherneck’s DCS Viggen has heart.

I’ve written about the Viggen’s history already, so if your first thought is, “Why should I care?”, there’s your answer. With that out of the way, we can move onto the plane itself.

Graphics
Digital Combat Simulator made huge strides on this front with the release of its new rendering engine in 2015; Leatherneck has proven itself well above average at the graphical side of DCS module development. The MiG-21 was a work of art, and the Viggen is perhaps even more so. The external model is well done, and seems perfectly realistic to me1. The real artistry comes inside the cockpit, though. Flip on the battery and the low pressure fuel pump, and the master warning lights (labeled HUVUDSVARNING, because Swedish) come on, bathing the cockpit in a luminous flashing red. Turn them off and get through the rest of the startup checklist, then turn the radar on. The CRT casts its eerie green CRT glow over everything, and seems to glow with the inner light all displays of its type do.

Beyond the superb lighting effects, the cockpit also has the weathered feel you would expect from twenty-year-old airframes. (Remember, the AJ 37 Viggen is a 1970 plane; the AJS 37 Viggen is the 1990s update). It isn’t dingy, but it does look and feel as though it’s been used, and that adds tremendously to the plane’s character.

Sound
We come now to perhaps the best part of the Viggen: its sound design. Although the DCS engine may not do very well at exterior sounds for any plane, Leatherneck has still managed to make the flyby sound meaty, especially in afterburner. In-cockpit, the state of things is much better. Turn on the AC power, and the computer’s fans spin up with a sound that reminds me of my childhood machines. The master warning alarm has the same warmth to it as the light does. Later, the insistent chirp of the radar warning receiver gives way to the thunder of the afterburner, growing deeper by stages as the throttle clicks past its detents through the three afterburner power bands.

Sound is an important and underrated component to immersion in sims. The Viggen gets it spot-on. It’s good as any sim I’ve played to date.

Systems and weapons
The Viggen flies a mission profile rather out of favor in today’s world: interdiction. That is, it’s designed to fly at ludicrously high speeds and ludicrously low altitudes, carrying a wingload of bombs, rockets, or rudimentary guided weapons. It gets to its target, pops up at the last minute to aim its weapons, makes one pass, and heads home.

This is reflected in its design: the canarded double delta makes quite a bit of low-speed lift, but it does so inefficiently. The Viggen is happiest in its native habitat: Mach numbers greater than 0.6, altitudes lower than 500 meters above the ground. It does not fit into the low-intensity COIN world of DCS nearly so well as (say) the A-10C, the Ka-50, or even the Su-25. The weapons fit requires you to know where your target is, and even the air pressure at the target’s location. All of this (except for the air pressure) must be programmed into the computer ahead of time, or using the wee six-digit input display while flying.

So, don’t expect to do much loitering, waiting for JTAC, and dropping bombs precisely. Even if it was more straightforward, the Viggen has very little facility for dropping quantities of its weapons smaller than ‘all’. Only guided missiles fire one at a time.

Having introduced this section with an extended ramble, let me get back on point for a paragraph. The systems modeling feels right to me. I’m not an expert on Swedish systems of the 1970s and 1990s, but everything feels plausible enough, modulo some early-access issues Leatherneck is working through in weekly patches. Notable fun items include the overwhelmingly programmable RB-15 anti-ship missile, the BK-90 totally-not-a-low-altitude-cluster-JDAM, and the RB-05A manually-guided missile (easier to use than it sounds). The air-to-ground mapping radar works as expected; that is to say, it’s very cool, albeit with the confusing wrinkle that green means no radar return and black means return.

There are some ongoing issues with rearming, as well as some others involving weapons and multiplayer, but I’m confident Leatherneck will be able to get those squared away.

Gameplay
On to the most subjective point! Is it fun?

Yes. Yes it is.

The design of the HUD, with few numbers and lots of indicator lines, makes you feel like you’re flying a Swedish X-Wing, and the rest of the cockpit supports that impression. As the treetops zip by at four hundred knots, and the waypoint distance line on the HUD shrinks to indicate you’re closing in on your target, you can just picture yourself hurtling down the Death Star trench.

Maybe that’s an exaggeration, but the Viggen’s mission profile makes for a certain sense of rising anticipation as you speed toward your target. Do you know that stereotypical scene from adventure movies, the one where the sun inches toward a bejeweled staff placed just so, or the one where some narrator is speaking while an orrery clicks toward planetary alignment? Everything is building toward a single moment, and then, bam—the payoff. The sun sparkles off the jewel and lights up the model of the city below, the orrery’s planets align. That’s the feel of a Viggen mission done correctly. Your range-to-target dial—and it is a dial; the Viggen may be computerized, but it isn’t that computerized—ticks down toward zero. You pull up, catching a glimpse of your target as you do. You roll onto it, lining up the sighting mark in the HUD, and then, bam. You pull the trigger and your weapons strike home. There’s the payoff.

It’s tremendously exciting.

Verdict
I recommend the Viggen wholeheartedly, based on its production values and on the sheer thrill I get out of flying it. I offer the following two caveats, though. First, it’s an early access product; more importantly, it’s an early access DCS product. There are still plenty of gremlins. Second, if you’re a multiplayer-primary player, be warned that there are several bugs and several usability issues to contend with. Even with those caveats, though, it’s an excellent aircraft, and I very much doubt you’ll be disappointed with your purchase.


  1. I don’t count rivets, though. 

Resurrected Weapons: Douglas F6D Missileer

We looked at the long-range, high performance Eagle missile on Tuesday. Now, let’s look at the plane to carry it.

As ever, the US Navy was concerned about saturation attacks on its carrier battle groups. To counter the new threat of bombers armed with large, long-range antiship missiles, the Navy had two projects under development in the late fifties. One was the Typhon long range SAM, with a projected range of 200 nautical miles. The other was the Eagle/Missileer project.

Missileer was, unusually for the jet age, a subsonic fighter. Given that it had to stay on station more than 200 nautical miles away from the fleet, and that more loiter time was significantly better, the decision was made to keep the design subsonic. Long loiter also conveniently sidestepped delays in interception from launching alert fighters, since the fighters could be orbiting and ready. Subsonic design made mounting a large, advanced radar and large, advanced missiles easy. We’ve already talked about the massive, 1,284 pound Eagle missiles. The Missileer was designed to carry six of them. It was also designed around the large APQ-81 radar.

APQ-81 was an early pulse doppler radar. In an era when a fighter radar with a 24 inch diameter dish was considered large, APQ-81 had a dish 60 inches across. It could detect a standard radar target1 at 120 nautical miles, and track sixteen of them simultaneously at 80 nautical miles. It had a track-while-scan mode. It was designed with innovative anti-jam features from the beginning, including a narrow, 3° beam with a 24 kHz bandwidth, both chosen to avoid most available jamming systems.

Unsurprisingly given that it had to carry such a large load, the F6D was fat and ugly. It was 53 feet long and had a wingspan of 70 feet. It was powered by a pair of Pratt & Whitney TF-30s, engines that would go on to power the F-111 and the F-14A.

Like the AAM-N-10, he Missileer was cancelled by McNamarra to free up budget space for other things. The aircraft itself would be easy to develop but the radar and systems integration (and the AAM-N-10) would be risky and expensive. Plus, they’re overspecialized for a single mission. The F6D had to be bought in conjunction with another, more conventional fighter, since it could not provide strike escort capability or establish air superiority. It was a project that was somewhat ahead of its time, like Typhon. The US Navy would later get a much more reasonable set of systems with similar capabilities in the 1980s with Aegis and Tomcat/Phoenix.

Verdict: Funding request denied by the Borgundy Aircraft Procurement Board


  1. In the late 1950s, the standard radar target was assumed to have a radar cross section of 5 square meters. This corresponds to the radar cross section of a B-47 bomber. 

F-35 First Red Flag Performance

The F-35A is at its first Red Flag! And we’ve gotten some reports of how it’s doing.

First, a little review. Red Flag is the most advanced aerial combat exercise in the world. In a given year, there are several Red Flags, operated out of Nellis Air Force Base in Nevada and Eielson Air Force Base in Alaska. There, the US Air Force and US Navy squadrons join with squadrons from other NATO and Non-NATO allies to engage in a series of realistic training exercises. They have the full suite of AWACS support, and air combat is staged against the Aggressors, instructor pilots who fly F-15s and F-16s and are trained in a wide variety of foreign flight tactics.

The Aggressor pilots are the best dogfight pilots in the world. That is literally all that they do. Their job is to be the nastiest guys in the sky, to catch pilots making mistakes in training where there’s a nice debrief so they can learn from their errors. Beats the Hanoi Hilton.

And the F-35 is, of course, the next fighter of the US Air Force, the US Navy, the US Marine Corps, the Royal Navy, the Israeli Defense Forces, South Korea, Australia, and a whole lot of others. It’s a huge, complicated, advanced program. And it’s had its share of problems as well as its share of detractors. And it was my pick for Borgundy’s Fighter in the Procurement Games. Despite the problems, I stand by that decision.

So with all that in mind, let’s see how it did. Keep in mind, this is only one Red Flag exercise. Small sample sizes can lead to problems. But it’s the data we have, and given the questions, it’s worth commenting on now.

As befits USAF doctrine, the F-35 has been primarily tasked with strike and SEAD missions. The USAF has F-22s for air combat. And the F-35 has done great. They didn’t lose any fighters on day one of the exercise when they engaged enemy air defenses, which is not something that usually happens. The Aggressor Team had to revise their exercises to be more complex and difficult in order to make life more difficult for the ‘Blue’ team (the good guys with the stealthy fighters). These tests are only interesting when they are hard.

But let’s talk about dogfighting. Nobody else has Raptors, so the rest of the world will need the Lightning II to be ready to mix it up, and the F-35 got some dogfights in. We do not know any of the specifics of the engagement–range, circumstances, rules of engagement, simulated loadouts, etc. But we do have a final score. 15-1 in favor of the Lightning. Questions abound, of course. What were the rules of engagement? What were the circumstances? Were these all WVR? BVR? We do know that the Aggressor pilots have had a lot of experience dogfighting (and mostly losing) to the F-22, so they may have been a little more ready for the F-35 than one might otherwise expect.

Pilot impressions of the Lightning II continue to be positive. The situational awareness is better than anything else in the sky, and unsurprisingly, pilots love being able to see and know more. No complaints about the aircraft have emerged. Also, it’s done great on the flightline. No F-35s have missed a sortie for maintenance problems, and the planes report a 92% mission readiness rate. Most legacy aircraft have a 70-85% mission readiness rate.

So despite the problems, many of which do not affect the -A variant, we can see that the Lightning is doing well in unscripted exercises. It’s a very good sign for the program.

And no, we do not expect the program to be cancelled as part of President Trump’s review.

Sunday Puzzle: Air-to-Air Refueling Edition

Need something to wash the taste of Patriots victory out of your mouth? Try the Sunday puzzle.

Much ink has been spilled about the limited range of modern American carrier fighters. It’s one of parvusimperator’s biggest bugaboos. Sometimes though, it’s difficult to get a good sense for the penalties imposed by limited range. Let’s formulate it as a riddle.

You, Colonel Reader, command a fighter wing in Friendly Mideastistan. You have orders to strike a target in Enemy Mideastistan. Your target is six hours away from your airbase. Your fighters only fly for three hours on one tank of fuel.

Some additional parameters: your fighters fly at a constant speed without respect to payload or altitude, and their fuel consumption is also constant. You have exactly one airfield to work with, placed six hours from the target. Planes may not take off from or land anywhere else, nor may a plane run out of fuel in midair. (It looks bad.) Planes may refuel each other; there is no limit on how much fuel a plane may transfer. Takeoffs, landings, and refueling are assumed to be instantaneous.

Question 1: for each plane which drops a payload on the target, how many planes are required for refueling?

Question 2: describe the pattern of refueling which is required to get one plane to the target.

Answers and analysis:

Spoiler:

I first saw this as a question about circumnavigating the globe, so I’m going to talk about 180 and 360 minutes instead of 6 hours.

Two refueling planes are required per strike plane. All three take off at T+0. When they reach T+45, all three have 135 minutes of endurance remaining. The first refueling plane fully refuels the other two, at the cost of 90 minutes of endurance. It has 45 minutes of endurance remaining, and returns home. The other two have 180 minutes of endurance left.

At T+90, the first refueling plane has landed. In the air, the two remaining planes each have 135 minutes of endurance remaining. The second refueling plane fully refuels the strike plane. The refueling plane is left with 90 minutes of endurance, and the strike plane now has a full 180. The refueling plane turns for home.

At T+180, the strike plane drops its payload on the target, with 90 minutes of endurance remaining. The second refueling plane has landed. The first refueling plane, now refueled, takes off.

At T+270, the strike plane and the first refueling plane meet. The strike plane is running on fumes, with 0 minutes of endurance left, and the refueling plane has 90 minutes. It transfers half its fuel to the strike plane, leaving both with 45 minutes of endurance. The second refueling plane takes off.

At T+315, the strike plane and the first refueling plane meet the second refueling plane. The first two are running on fumes. The latter has 135 minutes of endurance remaining. It transfers 45 minutes of fuel to each of the first two planes, leaving all three with 45 minutes of endurance: just enough to get back to home plate.

And this, of course, is the best-case scenario. Our model is simplistic in the extreme; it doesn’t account for the time taken to refuel, the time taken to find the tanker, the difference between fuel consumption based on payload, the ordinary requirement that strikes be flown at a speed and altitude different from those used for best cruise performance, and a myriad of other factors.

Let us consider a real-world example which closely matches our riddle in its setup: the Black Buck raids, flown by the RAF during the Falklands War. The distance between the closest British airfield, Wideawake on Ascension Island, and Port Stanley Airport, in the Falkland Islands, is 6,300 kilometers. Different sources list the Vulcan’s cruising range at between 4,100 and 7,000 kilometers. Even if you choose the worst possible figure, the Vulcan’s endurance is nearly two-thirds the required range, much better than the half in our riddle. Of course, I haven’t been able to find actual range figures; this column does not merit that much investigation.

What it does merit, however, is the answer to our riddle for the real-world case. For each Vulcan strike (they were flown as single-aircraft raids), eleven tankers were required, refueling each other, then refueling the Vulcan six times on the outbound leg and once on the return trip.

Refueling is hard. Not only is it difficult mechanically, not only does it require specialized aircraft (or limited refueling performance, for buddy stores), it also gets you into a vicious cycle in the same vein as rocket design. When you have to carry your fuel, you need more fuel to carry your fuel to where it’s needed, and so on and so forth. The United States has an enormous advantage in that it already operates refueling assets worldwide; much of its fuel is already where it needs to be. This may not always be the case, hence our advocacy for aircraft designs with legs built in.

I hope you enjoyed the inaugural Sunday puzzle. There may be others.

Resurrected Weapons: A-6E Intruder

If my father’s generation wanted precision strike from the sea, they’d call up the ugly but effective Grumman A-6E Intruder. Looking like a drumstick with wings, the Intruder had a two-man crew, a radar-navigation system for night/all-weather guidance, and a FLIR system in a small turret under the nose for target identification. It was subsonic, had an approximately 600 nautical mile (a bit over 1,100 km) striking radius, and it could carry up to 18,000 lbs of bombs.

The long strike radius was a direct consequence of optimizations and the choice of subsonic speed. Grumman opted for subsonic speed, because even the big F-4 Phantom was subsonic when heavily laden with bombs. Accepting a lack of supersonic speed meant that more fuel efficient engines could be used, providing a long strike radius.

In the Intruder’s day, there were no smart weapons. The delivery vehicle was responsible for all of the precision (or lack thereof). This alternative is a lot easier, since the plane is a lot bigger and easier to fit sensors and targeting computers into. As a brief aside, this sort of precision-on-aircraft delivery of dumb munitions is still used by Russia, and was the delivery method of choice for the airstrikes in Syria.

The Intruder proved very effective in Vietnam, where it was the Navy’s most accurate bomber. It was also the primary Navy delivery platform for dropping laser guided bombs in Desert Storm, since the -E models had a laser designator in their FLIR turret.

Despite the Intruder fleet getting new wings in the early 90s and having a solid combat record, the Intruders were taken out of service in 1996. There really wasn’t a perfect replacement. It was supposed to be replaced by the A-12 Intruder II, a poster child for bad project management. This project was cancelled1 without anything new being proposed in its stead. In the late 90s, the Intruder’s role was supposed to be filled by F-14 Tomcats with LANTIRN pods, which could not match the payload capacity of the Intruder. In 2005, the Tomcats were also removed from naval service, and their roles were taken over by F/A-18E/F Super Hornets. These could not match the range of the Tomcat or Intruder (both of which have a strike radius of about 600 nautical miles).

I really don’t like the loss of strike radius in the newer platforms. Super Hornets are nice otherwise, but they could really use longer legs. Yes, I know tankers have worked in recent conflicts, but the Navy shouldn’t rely on them. Or else what’s the point of naval aviation? If you can make tankers work, you can probably make land-based strike work. The whole point of naval strike is to be deployable quickly, and to come from additional vectors. In Vietnam, carriers at Yankee Station brought strikes from the east, in addition to the USAF strikes from the west out of bases in Thailand. If they required tankers, that makes life a lot more difficult for the planners, since tankers are fat and vulnerable.

The Intruder was cancelled to reduce the number of airframe types in the fleet. Understandable, but likely premature. The limited wars of the 2000s and 2010s would have been a good match for the capabilities of the Intruder. The A-6E isn’t very survivable in a high-threat environment, but Al Qaeda doesn’t have any serious SAMs. Long range would also make for long loiter time, and adapting a plane for JDAMs isn’t exactly hard.

On the one hand, restarting A-6 production would be silly. On the other, they were taken out of service way too early, and there’s no real replacement out there.


  1. The A-12 is a program that even I think deserved to get cancelled. 

Swedish Strike Saturday: the AJS-37 Viggen

The AJS-37 Viggen is a modernized classic: a 1990s update of the 1971 AJ-37 Viggen.

Why is it a classic, though? You may be forgiven for not knowing. In fact, I did not know until I saw that Leatherneck Simulations1 are making a DCS AJS-37. So, on this first Swedish Strike Saturday, let’s take a look at why the Viggen is such an icon, and why you ought to be excited for it.

In doing so, we first have to take a trip back in history, back to Sweden circa 1961. The enemy du jour is the Soviet Bear. Although the Saab 35 Draken matches up well against Soviet fighters of the day, the Saab 32 Lansen, a late first-generation jet which handles the attack role, is looking a little long in the tooth. It’s time to make something better.

Much better. The Swedes had a history of pioneering aircraft designs out of Saab, and the Viggen was no exception.

It was the first canard aircraft to enter front-line service, and featured the first afterburning turbofan in a strike fighter. By date of start of development, the Viggen’s computer was the first integrated-circuit computer designed for use on an aircraft. For a time in the early 1960s, while development work was under way on the computer, Saab was the world’s largest buyer of integrated circuits. It was the first single-seat third-generation jet strike fighter to enter development, and the second to enter service2.

As one of the two first digital attack aircraft to enter service, it is, then, an object of some historical interest. Similarly, its computer is one of the first in the aviation world, and that makes it interesting to me (a computers guy). The CK37 (CK for Central Kalkylator) flight computer does just about everything data-related in the aircraft: it runs both of the cockpit displays (the HUD and the Central Indicator—think radar screen, but with navigational information, too), does navigational calculations, and handles weapon aiming.

Saab built the prototype, using individual transistors, in the 1960. It was table-sized, featured about 5,000 transistors, and ran at about 100,000 cycles per second. Total weight was about 450 pounds. Obviously, it wasn’t altogether suitable for aerial usage. Redesign efforts in 1961 used the newly-available ‘integrated circuit’.

Enter Fairchild, who beat Texas Instruments (!) for the contract. Their integrated circuits featured a whopping two transistors per square millimeter, ten times the density of discrete components. Some few years later, in 1964, Saab’s computing division delivered the final CK37 prototypes. This final version could run about 200,000 instructions per second, with about 28 kilobytes of magnetic core memory, with core density of about one core per millimeter3. It weighed about 150 pounds, comprised five computer units, and drew about 550 watts of power.

And, going by everything I’ve seen, it made for a tremendously effective aircraft. On seven hardpoints, the original Viggen could carry a combination of weapons: 135mm rockets, 120kg bombs, the RB-05A MCLOS missile, and the RB-04 anti-ship missile. Between the radar and the advanced (for its day) navigation system, the Viggen could fly in ugly weather, dropping unguided bombs precisely on any target it could see by radar. Although its air search capabilities were rudimentary, the radar could still cue Sidewinder seekers; on those grounds, it was not altogether ineffective as a fighter.

It did so without a navigator; the autopilot and navigation systems are sufficient to permit the pilot alone to fly and fight. By all accounts, the Viggen gave excellent service from its introduction date in 1971 to its retirement thirty-odd years later. Along the way, it gained the RB-75 missile4, and a variant called the JA-37. A fighter first and striker second, the JA-37 gained a better computer, a lookdown-shootdown radar, and support for the Skyflash5 missile. Much later, both the JA and the AJ Viggens saw some upgrades. The JA-37 became the JA-37D, with a glass cockpit and the ability to sling AMRAAMs6. The AJ-37 became the AJS-37, and that’s the plane we’re interested in today.

Development of the JAS-39 Gripen7, the follow-on to the Viggen and the Draken, began in 1979. It didn’t fly until 1988, and it didn’t enter service until 1997. In the interim, Swedish military planners began to get a little nervous about the state of their ground attack force. Though the Viggen was a solid workhorse, its armaments were outmoded, and its navigation system was fiddly.

Some of the Gripen’s weaponry was already available in the early 1990s, though, including the BK-90 submunitions dispenser8 and the RBS-15 anti-ship missile. The S-modification allows the Viggen to launch both, giving it access to modern smart weapons. At the same time, Saab’s designers added a data cartridge, greatly simplifying pre-mission preparation. The extra data capacity in the cartridge also allowed for a terrain contour matching function. The data cartridge contains information about the elevation contours expected during the mission and their locations; in flight, the computer correlates the expected contours to the actual, observed contours from the radar altimeter. This allows the computer to update the INS with true positions, correcting to some degree for drift during flight.

With those upgrades, the AJS-37 soldiered on until 2005, flying alongside the Gripen for eight years, at which point it was finally retired. An airplane of many firsts, it was also a notable last: the last of the great 1970s low-altitude strike fighters to fly its original mission profile. The Tornado, the F-111, and all the Viggen’s other contemporaries were upgraded to fly more modern, middle-altitude missions. The Viggen never lost its focus as a low-altitude interdictor.

Is the Viggen a good interdictor in its original threat environment? Do the upgrades make it better? Is it suitable for the modern world? How good is the Leatherneck recreation? This paragraph is where I had hoped to tell you that we would soon be finding out. Unfortunately, it’ll be a little longer than I had hoped; Leatherneck’s Viggen releases on January 27, and it isn’t looking like the Soapbox is big enough for a preview key. No matter—that just gives me more time to prep for the articles down the road. In February, you can expect two or three of them, touching on the answers to the questions posed at the start of this paragraph.

Stay tuned!


  1. Makers of the DCS MiG-21
  2. The A-7 Corsair came first, entering service in the late 1960s to the Viggen’s 1971 
  3. The CK37 divides its memory into 8192 words of 28 bits in length, with 1536 words as working space and the remainder write-protected data. 
  4. The AGM-65A Maverick; the Swedes have a thing about keeping American names for missiles. 
  5. Or RB-71. 
  6. Surprisingly, they call this one the AIM-120. 
  7. The Gripen is a longtime favorite of mine. 
  8. The Swedes are anti-cluster-bomb, so a weapon which drops explosive bomblets is called a ‘submunitions dispenser’. 

Cargo Helicopter for Borgundy

Between the two of us, Fishbreath is the clear rotorhead. And that’s fine. He really likes flying helicopters in sims.

I, on the other hand, am coming at this from the logistican’s perspective. I’m looking for a helicopter to haul stuff. It should be cheap. It should be reasonably modern. It should be readily available in numbers. Armored thrusts need lots of fuel, ammo, and food, and we need ways to get that materiel to the front. Let’s look at some big, ugly cargo helicopters. They’re probably no fun to fly, but they’re important just the same.

The most obvious choice would be the Mi-26. The biggest helicopter in mass production. Of course, being Russian, lower initial purchasing price comes with higher maintenance costs. That’s not a big dealbreaker though. Of greater concern is the revanchist Russian bear. Can they be depended on to supply spare parts in the future? The production line is also moderate. Besides, I’m sure Fishbreath is waiting to throw politics into this. Let’s dig deeper.

We come to that big, US Army classic: the CH-47F Chinook. It’s been in production since 1962. It can carry 55 men or just under 11 tonnes of cargo. Three machine guns can be mounted to cover soldiers. It maxes out at 170 knots. Plus, the price is reasonable. Not quite Russian cheap, but the service life is better, especially as far as engines are concerned.

Compared to other Western options, the Chinook is a real bargain. It’s almost one third of the cost of the big CH-53K, but carries two thirds the payload. Also, unlike the CH-53K, it’s in full-rate production now. It’s also a pretty common helicopter. This means spares are easy to come by, the secondary market can supplement our orders, and most importantly, that someone else (namely the U.S. Army) is on the hook for funding upgrades, not us.

There’s not much out of Europe that can lift as much as a Chinook can. The NH90 can’t (it’s more of an oversized Blackhawk), and it’s more expensive to boot. Plus, it’s been plagued with all manner of difficulties. Not that the Chinook hasn’t, but any such problems are long ago. Call me when the NH90 has been through several wars.

Like most modern helicopters, the Chinook has plenty of optional extras. High end digital controls built under common architecture principles are readily available, along with midair refueling equipment and modern composite rotors. There are three pintles (left, right, and rear exit doors) for mounting machine guns. It’s got a long, proven history of good service.

There’s not much more we could ask for in a cargo helicopter.

BVRAAM

The Beyond Visual Range Air to Air missile is a critical munition in any air force arsenal. At first it might seem easy for a western air force. Call Raytheon, order up the latest version of the AIM-120 AMRAAM, and then call it a day and have a beer. Is it really that easy? Let’s take a look.

The AIM-120 AMRAAM was the world’s first missile with an active radar seeker, and it has become the world standard. It was designed to replace the AIM-7 Sparrow semi-active radar homing missile. It features improved range, and a way-cool seeker. The Sparrow’s semi-active radar seeker requires an external source of radar to illuminate the target, usually the firing aircraft. So the aircraft has to keep flying more-or-less towards the target while the Sparrow is in flight. This strongly limits the evasive maneuvering possibilities of the launch aircraft. If the radar lock is broken, the missile becomes a useless ballistic projectile.

The AMRAAM is different. It has an inertial guidance component for the initial run towards the target. It can be updated by radar from the launch aircraft. Then, when it gets close enough to the target, it turns on the active radar seeker. This has it’s own radar, so the launch aircraft is free to turn away from the target aircraft. It’s a big improvement. The seeker can also home on jamming if the target aircraft tries to jam it.

Okay, so that’s cool. The rest of the AMRAAM is pretty typical: it’s a single-pulse solid fuel rocket. So once you light it, it burns until the fuel is gone, and only burns once. This means that during most of the intercept it’s coasting. There are also dual-pulse rockets which relight later, which helps chase down a maneuvering target. But those are more expensive, and while there’s been a lot of discussion about putting one on the AMRAAM, that still hasn’t happened yet. The AIM-120D gets its improved range from improved guidance algorithms and GPS-aided navigation. Cool. The question becomes: can we do better.

We’ll need to take a brief interlude here to define a term: the no-escape zone. This is the range in which a target can’t escape a missile by outrunning it. Outside of the no-escape zone, a fighter can turn away and light afterburners and the missile will be unable to catch it. Within the no-escape zone is not a guaranteed kill, it merely forces the fighter to maneuver aggressively to force the missile to miss.

Anyway, the Europeans have designed something nice for once in an effort to do better, and are actually getting it to market in a sort of timely fashion. This is the MBDA Meteor AAM. It’s noteworthy for two reasons. First, it has a datalink for midcourse guidance updates from the launch aircraft, which improves the accuracy of the midcourse phase of the flight at longer ranges. More importantly, it has a snazzy new engine. This is a “throttleable ducted rocket” also known as an “air-augmented rocket,” but it’s easiest to think of it as a hybrid solid-fuel rocket/ramjet motor. Like a rocket, it can give useful thrust from zero speed. Like a ramjet, it can also pull in outside air, and has no moving parts. This means it gets way more burn time from its motor, which means that it has a much bigger no-escape zone. Even the way-cool guidance algorithms in the -120D can’t get around the fact that the Meteor has a more advanced engine that provides more oomph. The Meteor isn’t that much bigger than the AMRAAM either, at least as far as length and weight. It might take some doing to get it certified for internal carriage on the F-35 though.

So where does that leave us? The Meteor is the better missile, with the bigger price tag. We’d say it’s worth it though, especially to get those early shots in on Flankers. We’ll have to spend some money to get it qualified on legacy platforms, but that’s totally worth it for the leg up on potential enemies. It’ll be interesting to see if the AMRAAM ever gets that improved motor.

CAS Aircraft Throwdown: A-10C vs. Su-25T

Fishbreath and I have spent lots of time studying these aircraft and flying them in DCS. They represent two different philosophies for air support, the clash between ‘push’ from the top and ‘pull’ from the bottom. Plus, they represent some different design philosophies. We’ve talked about these two planes already, but let’s break everything down and see how they compare directly. Features are in no particular order.

WEAPONS:
We’ll break these down by type, and then tally up an overall score for this section.

GUN: A-10C
This is no contest. The A-10C has the GAU-8A, which is the most powerful flying gun around. It’s got better AP rounds than the GSh-30-2, and more than five times as many rounds in the magazine (1,174 rounds as opposed to 250). The A-10C has some nifty pilot aids to stabilize the aircraft on a gun run too, but the Su-25T just leaves you to your own lack of skill. Interestingly, the Su-25T also doesn’t have enough dispersion built into it’s gun. The A-10’s designers recognized that being exactly on target is very hard, so the gun has some built in dispersion to give you a margin of error, which makes it a lot easier to hit things.

ROCKETS: Su-25T
This is also no contest. The Russians like their rockets, and have a wider variety of sizes available. Even if we restrict to the standard small rockets (Russian 80mm S-8 and American 70mm Hydra 70), the Russians have a wider variety of warheads available, including exotics like thermobarics.

UNITARY BOMBS: A-10C
Both have the ability to drop laser guided bombs, plus plenty of dumb bombs. The A-10C can drop JDAMs (GPS guidance). The Su-25T can’t drop Russian GLONASS-guided bombs, but they do have the ability to drop bombs with the Electro-optical guidance system (they have a -Kr suffix). That said, the A-10C has glide bomb options, and the Su-25T doesn’t, giving the ‘Hog some excellent cheap standoff attack options. Glide bombs rock.

CLUSTER BOMBS: A-10C
Both have a lot of cluster bomb options, but (for now, at least), the Americans do cluster bombs better. The CBU-87 doesn’t really care at what altitude/airspeed it’s dropped at, and drops bomblets that combine antipersonnel, anti-armor, and incendiary effects in each bomblet. That’s pretty cool, and is a big logistics simplifier. It’s compatible with the wind-corrected munitions dispenser add-on kit, which isn’t really guidance, but it does ensure that the bomb dumps the submunitions where you intended, rather than get all mucked up by the wind. The CBU-97 Sensor fused weapon is also pretty sweet. It’s designed to scatter smart anti-tank munitions that will search for a tank beneath them as they fall, and then fire an explosively-formed penetrator at it if a tank is detected. The Russians don’t have such fancy anti-armor measures, and they don’t have fancy wind correction kits. They also don’t combine effects frequently in their bomblets. And altitude matters for the dispensers.

MISSILES: Su-25T
Given how much tech the Americans like to fight with, this might be a shock. Both aircraft can carry older WVR AAMs on the outermost pylons that can’t do much else. The A-10C can also carry a bunch of Mavericks, and that’s about it. The Maverick is a great air to ground missile, with a variety of guidance options. The Su-25T can carry the Kh-25 “Maverickski”, and the Kh-29, which is something like a bigger Maverick with a bigger warhead. It can also carry 16 9K121 Vikhrs ATGMs, so it ends up with more anti-tank capable missile capacity. You can also add an ELINT Pod and antiradiation missiles for SEAD missions. The A-10C has no such capability. The A-10C would certainly benefit from being able to sling Hellfires.

WEAPONS SCORE:
A-10C: 3
Su-25T: 2

MOBILITY: TIE
I’m not actually going to break this one down. Either way you look at it, it’s a tie. The Su-25T is faster. The A-10C has more range. The Su-25T was designed to be sent out from a forward airbase towards a given concentration of enemies. So it’s superior speed is more useful in that doctrinal role. It’s designed to go out, kill some stuff, and go home. Loitering is not called for, so plenty of range isn’t needed. The A-10C was intended to loiter near the battlefield until called for or it’s out of ammo. So range is good, because range translates into loiter time. Since it’s supposed to start in the air close to where the action is, it’s inferior speed isn’t a great handicap. Each does one thing better, and each has an attack doctrine built around its strengths.

DURABILITY: TIE
Both have a whole bunch of design features to make them tougher. Absent some kind of common destructive testing, this one is too close to call.

OTHER:
The category for random things that I can’t think of another place for.

LOCATING TARGETS: A-10C
This one’s almost not fair. The A-10C has a bubble canopy to provide good, all-around visibility. Plus, the A-10C has the LITENING pod, and this makes the Shkval look like a cardboard tube duct-taped to the cockpit. The LITENING has way more zoom, more resolution, a nearly-all-around field of view, and remembers what you were looking at if you have to make some turns, or if some part of the plane gets in the way during a turn.

SCORE TALLY:
A-10C: 6
Su-25T: 4

So the A-10C is better.

Or at least, in this simplified metric evaluation, the A-10C is the better plane. Really, the more relevant question is “Which doctrine do you prefer/buy into?” and to a lesser extent “Whose weapons are you buying?” since those questions will determine which will work for you, and if you’ll have to pay a bunch of annoying weapons integration costs and do some testing. Better electronics would go a long way toward improving the Su-25T, especially in the target acquisition phase.