Tag Archives: aircraft

Retro Procurement: Harriers for Luchtburg?

The year is 1993. A small Central American state, wealthy by the sale of unregulated and questionably ethical banking services to nations the world around, finds the firehose of Soviet arms slowing to an occasional drip when the Russians remember they sell weaponry. At the same time, in a newly multi-polar world, with trade opportunities abounding and the demand for questionably ethical banking services skyrocketing, Luchtburg finds itself in ever higher demand. Its interests overseas grow day by day.

Its defense apparatus is poorly suited to overseas interests. Having bought primarily from the Soviets, Luchtburg has a bunch of short-ranged interceptor-type fighters and interdictor-style attack aircraft, little access to smart munitions, and a token navy based around export-model Kilos and various frigates with anti-ship missiles. Not a great force for projecting power around the world, it must be said. So what’s a newly-flush nation to do? Buy weapons from Uncle Sam, of course. Eager to flip a previously-Soviet-friendly nation to to the side of truth, justice, and the American way, the United States invites a delegation from the Luchtbourgish Ministry of Defense to talk about Luchtburg’s future role on the world stage.

The answer, of course, is aircraft carriers. The problem is, Luchtburg might be flush, but it isn’t flush enough to buy a Nimitz-class, and the Americans aren’t selling, either. What the Americans propose instead is this: buy a bunch of the brand-new Night Attack Harriers and two old, recently decommissioned LPHs: USS Iwo Jima and USS Okinawa. No Tarawas are on the table. They still have too much life in them. No Wasps either; they’re too new. The most the Americans will do is maybe build a ski jump onto the Iwo Jimas, and perhaps extend the flight deck a few feet either way.

Is it a good buy?

The Harriers

The Harriers are a no-brainer. They’re pretty much the most recent ground attack aircraft built, support tons of modern American smart weapons, and have no replacement in sight. The latter point is important, given that it means they’ll see future upgrades and maintenance over the years. Luchtburg doesn’t want to buy a dying system, and the Harrier is just hitting its stride.

In the future, the Americans may be open to selling us the AV-8B Harrier II+. The Plus model includes a radar scavenged from old US Navy Hornets, and can carry the new AMRAAM missile. Of course, we aren’t close enough to the Americans for that yet, but having a fighter with modern BVR missile capability would be a huge win for the Luchtbourgish Air Force, even if it doesn’t go supersonic.

Accident rates may be higher for the Harrier than for more conventional aircraft, but the Harrier II is still new, and the Americans are still making airframes and parts. We’ll buy a few extra, and keep a tab open with McDonnell Douglas.

The Iwo Jimas

Now for the Iwo Jima-class LPHs. This is a slightly harder question. At first glance, they look like your standard straight-deck not-quite-aircraft-carrier. Big open flight deck, deck edge elevators, hangar deck of reasonable size. The Harrier is small and the elevators and hangar are sized for biggish helicopters, so from that perspective, the Iwo Jimas are big enough.

They have some downsides, though. For one, they aren’t quite as fast as we might like, with a top speed of 21 knots. For another, they have a slight operational problem, owing to their single-shaft design. Rather than describe it, I’ll quote an evocative passage from Marines & Helicopters:

One characteristic was first noticed shortly after the Iwo Jima left the dock on 5 September 1961 for her initial tests at sea. […]

Obviously such an innovative design was going to have a number of small discrepancies on her first shakedown. The Iwo Jima did. One of the most serious was described in the initial reports as: “serious hull vibrations at high power.” […]

This characteristic vibration was never to be cured in any of the class. At about 15 knots the entire ship began to shake every time one of the blades of the screw took a bite of the water. At that speed it was slight throughout all the ship, but more pronounced in the stern and bow Marine berthing areas. As the speed increased, the vibration increased correspondingly in frequency and severity.

Embarked Marines learned to recognized it and within a short period actually could tell how fast the ship was going by the rattle of the decks. It was as if the builders had given each man aboard the vessel his own private speedometer. As the Iwo Jima and her sister ships reached 21 knots the pounding became more pronounced and was inescapable anywhere on board. To the builders this was “severe vibration at high power.” To all Marines who experienced it, it was “the twenty-one knot thump.”

Amusing, but less than ideal, and perhaps concerning for aviation operations where 20 knots of wind over the deck is already a bit less than might be desired.

Speaking of, just how well is the type actually suited to flying Harriers? Take a look at it from above, and it strongly resembles the later Tarawa type, with the exception of some more rounded deck edges. Take a measuring tape to it, though, and you’ll find that the flight deck is only 600 feet long, against 800 feet on the Tarawa. That’s not so great. How big a deal is it, exactly, though?

In a previous post, I found some reference material on Harrier takeoff rolls and worked through some examples. By the book, with a 20-knot headwind (nearely all the Iwo Jimas can muster), you can fly a 26,000-pound Harrier off of a 500-foot deck. (Figure we’ll leave a 100-foot margin to allow for easier spotting.) The Harrier II’s maximum takeoff weight is some 31,000 pounds. I suspect the book has some margin for error: in DCS, I can pretty readily get a 30,000-pound Harrier off the Tarawa with room to spare.

Still, though, the Iwo Jimas give up a lot of capacity. I think the right decision for Luchtburg is still ‘sure, throw them in’, especially given that, at this stage of their careers, they won’t cost that much more than a Harrier. Luchtburg’s shipyards can get up to speed on aircraft carrier-ish projects by building a ski jump and an aft deck extension to provide a bit more off-the-deck capability.

Cool Hornet Features

The F/A-18 Hornet is a really neat aircraft. While it didn’t win our Retro Light Fighter contest, it’s still an awesome plane with a couple unique options. Let’s take a look.

ATARS
ATARS, or Advanced Tactical Airborne Reconnaissance System, combines image capture, datalink and image storage capability in one package. It’s got both visible-spectrum and thermal cameras, two data storage units, an interface with the APG-73 radar to save synthetic aperture radar imagery, and a datalink. That datalink can transmit to any Common Imaging Ground/Surface Station compatible system. The coolest part about ATARS is that the package fits in the gun bay of a F/A-18D, so it doesn’t require a big, heavy, draggy pod.

Night Attack Variant
The Guy in the Back isn’t a very popular feature amongst fighter pilots. The regular -D model Hornet has the usual second set of flight controls there. But under the Night Attack program, these were replaced with a dual-sidestick layout of the back seat cockpit of the Strike Eagle. Also, the center Multipurpose Color Display and Upfront Controller were transposed. This gave a position optimized for using the targeting pod and guiding weapons. I’m surprised Fishbreath hasn’t gone for this more, being a carrier-capable, smaller, cheaper strike fighter. The Night Attack layot could be swapped back to a conventional trainer rear cockpit, with center stick and throttles. This was not common practice though.

Looking for STARS

No, this doesn’t involve a trip to the Arklay mountains. Today, we’re looking into aerial systems for monitoring ground combat and enemy forces, also known as ISR (Intelligence, Surveillance, and Reconnaissance). This is an often-overlooked capability, and while such systems are not foolproof, not having them can lead to a lot of embarrassment. The notion was a key part of late-Cold War Airland Battle tactics, where ISR platforms could provide targeting data for long range weapons to atrit Soviet forces before they made contact with friendly ground troops.

In terms of current capabilities, the United States has the only serious capability worth writing home about, using the E-8C JSTARS. These put a powerful, GMTI/SAR capable radar on a Boeing 707 airframe. They have proven to be extremely effective when deployed, and were sorely missed by the Europeans during their recent Libya “intervention.”1 Of course, we can’t just buy these, because the 707 is long since out of production. Also, the USAF hasn’t really decided how it wants to proceed to replace or recondition the E-8Cs. We’ll look at other people’s ISR platforms as well as things that were proposed to replace the JSTARS.

The UK operates four Sentinel R1s, built by adding the appropriate radar systems to a Bombardier Global Express business jet. This is a relatively low-cost airframe, being a business jet, though the usual UK small orders means the net result is still going to be expensive. Also, lots of the analysis and battle management workstations are ground-based, for better and for worse. A Global Express 6000 derivative was one of the proposals for a JSTARS replacement.

Brazil has deployed three R-99s, ERJ-145 conversions with the appropriate SAR capable radar, to monitor illicit narcotics tracking and other illegal activities in the Amazon basin as part of the SIVAM. Unfortunately, I don’t know that much about the radar system deployed, and this one wasn’t proposed for the JSTARS replacement, so it’s not using that particular radar package.

Gulfstream also has an offering to replace the JSTARS that is based on their G550 SEMA variant, though with more radar focus than EW-focus. The SEMA version of the G550 is in use by the Israeli air force and has recently been purchased by Australia. There’s also a significantly reworked G550 variant, originally used with Conformal Early Warning2 arrays by the Israeli air force in the AEW&C role. The CAEW variant has also been purchased by the US Navy for monitoring their missile test ranges, and is to be reworked by L3 with electronic warfare systems in the conformal fairings to replace the EC-130H Compass Call in USAF service.

Boeing has a 737-derivative, which is pretty similar to the P-8, other than having a radar optimized for a different mission. Radar options for the JSTARS replacement proposal were similar to those of the bizjets. Annoyingly, the product page for this is no longer on Boeing’s website. The strangest thing about Boeing’s proposal (sparse as the details are) is that it didn’t do all that much to take advantage of the extra space, weight, and power capabilities of the 737 platform.

At the end of the day, 8-10 analysts doesn’t require a 737, and if you’re not going to load it up with a big radar, you can go with a smaller, more fuel-efficient jet.

Let’s also talk about the Global Hawk. The RQ-4B Block 40/RQ-4D variants come equipped with a small version of the MP-RTIP radar originally intended for the E-10A. That’s a pretty fantastic radar, and the RQ-4D3 is the highest-flying option. It does not operate in adverse weather conditions though.

Alright, let’s get picking. We’re going to want some RQ-4Ds because of that fantastic radar and because it’s a pretty natural fit for a UAV. There’s a big NATO buy at the moment, and we’d like to get in on that model. We’re also going to want a manned option though, which means we’re going to have to sort through the business jet contenders. In terms of radar systems, all of the JSTARS replacement offerings had a similar radar fit, which doesn’t help us much. According to the Business & Commercial Aviation 2018 buyer’s guide, the G550 is a little cheaper than the Global Express 6000, but the difference is probably too small to matter.

What is different is that there are a lot more military G550 variants in service. There’s also the flight tested CAEW airframe, which is useful for a few other purposes besides the AEW&C role it was originally intended for. So we’ll go with that one, since it gives us a few more options for related aircraft down the line. We especially like the idea of an electronic attack version.


  1. Or whatever we’re calling “it’s not a war because shut up” these days. 
  2. If I was going to go with a business jet derivative for AEW&C the G550 CAEW would be it, because it has a pretty nice radar, and the conformal array fit is cool. But the Wedgetail radar is a more powerful one. 
  3. The RQ-4B Block 40 that a bunch of NATO partner nations are buying. Because that totally deserves a new designation. 

Maritime Patrol Aircraft

Today we’re talking maritime patrol aircraft. There are two on the market worth looking at: Boeing’s P-8 Poseidon and Kawasaki’s P-1. Let’s look at them both and see what we like.

The Poseidon was designed to replace the P-3 Orion, and the P-8 is based on the Boeing 737-800ERX, which means it has the fuselage from the 737-800 and the wings from the 737-900. So it’s based on a recent model of a very popular airliner, which keeps airframe costs down and ensures a good supply of future spare parts. The Poseidon has a weapons bay located behind the wing, with five weapons hardpoints. An additional six hardpoints are under the wings. This bay might seem a little small, but you can’t actually put the bay between the wings, because that’s where the structure is to support the wings.

Sensorwise, the P-8A is equipped with the APY-10 multi-mission surface search radar, plus facilities for a large number of sonobuoys, and an EO/IR ball turret. It even has a sensor to detect emissions from diesel ships and submarines. In its standard, USN model, it does not have a magnetic anomaly detector (MAD). This was per a NAVAIR request to reduce weight and improve range. It also allows for a higher-altitude flight profile that is more fuel efficient, especially for an airliner-derived platform. In turn, the lack of MAD has been frequently criticized. It should be noted that this shouldn’t be seen as an indictment of the platform; regardless of what you think of the US Navy’s decision the P-8 can be equipped with a MAD, and the version for India has been sold with one.

The P-1 was also designed to replace the Orion, and it took a notably different path. It’s about the same size as the Poseidon, but it’s optimized for lower-altitude flying, with less-swept wings. It’s equipped with advanced avionics, including a fly-by-light flight control system, an HPS-106 AESA surveillance radar, and a magnetic anomaly detector standard. It has eight internal and eight external hardpoints for weapons. It does not have provision for midair refueling.

In terms of comparatives, the P-1 has more weapons capacity, and flies the traditional lower altitudes of the P-3 Orion. The P-8 is a higher altitude aircraft, for better and for worse. The P-8 has a big edge in terms of costs, being based on a currently-produced airliner, being in higher-rate production, and having tons of spares readily available. The popularity of the 737 platform will mean that there will be a large supply of future spares too.

And, like everyone else who has looked at these two, we’re going with Poseidon. Which begs the question, to MAD or not to MAD? I’m going to hedge here, because I really want to see some data or some test results, but I don’t have them as an armchair strategist. I’ll tentatively say “With MAD”, understanding that I’m open to data that I don’t have right now showing that it’s really not needed.

Choosing and Buying an AEW&C Platform

Airborne Early Warning and Control (AEW&C, often colloquially called AWACS even though that’s a specific system for the role) is what separates the Serious Air Forces from the cut-rate posers. The idea is to take a large airframe, usually a jetliner, put a big radar on it, and then have a bunch of people sitting at computers to coordinate your sorties. All the benefits of GCI in a portable package!

A large part of picking a platform is determining your constraints. We’re looking for a land-based platform that’s relatively low cost to operate and can handle a good number of friendly and enemy aircraft. For this reason, we’re going to look at the larger class of AEW&C platforms.

As a brief aside, the smaller platforms are the Northrop Grumman E-2 Hawkeye, and a number of business jet derivatives. The Hawkeye is the only decent carrierborne AEW&C platform available, so if we were looking to build a naval air arm, that’s what we’d pick for the purpose.

The obvious large AEW&C platform is the E-3 Sentry. However, it is built on a Boeing 707-derived airframe, and these are no longer in production. No luck there. This problem also presented itself to the Japanese when they were looking for a larger platform to supplement their Hawkeyes in the 1990s.

Boeing obliged with the E-767, which puts the radar and computers from the E-3 onto a 767-200 airframe. The resulting widebody has space for up to 19 controller consoles, though I couldn’t find a great source on how many the JASDF use. It still uses the same radar as on the Sentry, albeit with upgrades. Also, as presently configured, it has no aerial refueling capability.

About a decade later, Boeing responded to an Australian RFP with a new design: the E-7A Wedgetail. This aircraft is based on the 737-700 airframe, and mounts Northrop Grumman’s Multirole Electronically Scanned Array radar. This is an actively scanned array, so it doesn’t need to rotate. It does posses aerial refueling capability, and is capable of mounting up to twelve controller consoles. At present, Australia has fitted ten consoles.

In terms of bigger platforms, these are the contenders. More consoles on the E-767 means it can coordinate more friendly aircraft. The more advanced MESA radar on the Wedgetail lets it refresh scans of regions faster and adjust power to focus on particular sectors with longer-ranged scans. It’s also able to handle simultaneous air and surface search. and the actively scanned array should be better at ECCM.

You can probably see where this is going. We’re opting for the E-7A Wedgetail. It’s even the cheaper option of the two. It’s telling that Wedgetail has had several export successes since being sold to the Australians. It’s also telling that the E-767 is absent from most of Boeing’s current marketing materials.

Choosing a Tanker Aircraft

Tanker aircraft are a requirement for any serious projection of airpower. And no one ever has enough of them. So let’s go get some.

Previously, the standard in aerial refueling was the KC-135, a close relative of the classic Boeing 707. Today, there are two different airframes available for tankers. There is the Boeing 767 and the Airbus A330. The 767 has two tanker derivatives: the KC-767, which is derived from the 767-200ER and is in use by Italy and Japan; and the KC-46A, which is based on the 767-200LRF1 and is in use by the United States and Japan. Note that the KC-46A is bigger than the KC-767, and carries more fuel. The A330-MRTT is the tanker derivative of the A330, and it is bigger than the KC-46A.

Now on to the choices. We know from the USAF tanker proposals that the 767 options have a lower projected life cycle cost than the A330-MRTT. For many export customers, this is outweighed by the greater fuel and cargo capacity of the Airbus. On the other hand, the 767s smaller size means it can operate out of smaller airfields. It is closer in size to the KC-135R, for those looking for a direct replacement, or just trying to picture sizes.

For us, we’d also point out the massive USAF buy of KC-46As as points in its favor, since that will mean the type will get more future upgrades and development money, if only to keep the US fleet going. Further, 767s are Boeing aircraft, and have a flight envelope not restricted by the flight computer. We prefer this.

So we’re going with the KC-46A. It’ll get the upgrades, and Boeing is still making 767s for the civilian market, which is a plus. We expect to be able to cannibalize ex-civilian airliners for parts and airframes for years after the type is formally retired (as was done with the KC-135), but the longer we can go before having to do this the better.


  1. Which is actually quite a bit different from the 767-200ER. 

Choosing a Jet Trainer

While not glamorous, jet trainers are an important part of an air force’s inventory. And with the US Air Force looking for a replacement for its venerable T-38s, I thought I might do likewise. As always, we’re looking for something off the shelf, which is doubly important for a trainer. A trainer’s most important evaluation criterion is cost; it should be cheap to buy and cheap to operate. It should, however, have a reasonably sophisticated cockpit so students can start learning on the sorts of instruments they’ll see on your front line fighters, as this will reduce training time there.

Cost is always a hard thing for the armchair strategist to analyze, however recently Poland sought a new trainer. Looking at their tender, we can get an excellent idea of relative costs, since Poland makes none of the three leading contenders. They compared the current model of BAE’s Hawk trainer, Alenia’s M-346, and Korean Aerospace’s T-50. All three are new-build aircraft, complete with modern comforts like glass cockpits. Costs for the bid (for a fixed initial number of aircraft) broke down as follows: M-346: 1.168 billion złoty, Hawk: 1.754 billion złoty, and T-50: 1.803 billion złoty. The M-346 won in Poland. It has also won a similar comparison in Singapore, but I don’t have their competitive bids to examine.

We might next ask if we ask anything more of our trainer. Some smaller air forces have trainers that are tasked to also be light attack aircraft. Were this the case, like any other tender we’d start discussing payload and compatible weapons fit. However, since we do not have such a role in mind for our trainer, we do not need to make such comparisons.

Since the M-346 is our lowest-cost option that meets our capability requirements, the M-346 is our choice.

Retro Air Force Procurement II: Lightweight Fighter Edition

It’s time for another classic showdown. Let’s look at two competing lightweight fighters. Specifically, the F-16 Viper and the F/A-18 Hornet. We’re going to keep this fair, so we’re generally looking at older Vipers, from back when both were in production. For a mid 90s procurement challenge, we’re going to have the F/A-18C/D Hornets go up against the F-16C/D Block 50/52 Vipers.

The F-16 was the fighter that (re)popularized the light fighter concept. It’s relatively small, has one engine, and a reasonable amount of capability. For a western fighter, it’s pretty cheap too. One engine means that the maintenance and support costs are going to be lower. Plus, it’s engine is common with that of the F-15, which is awesome if you operate the bigger type. It has possibly the most cockpit visibility ever. It can do any mission you please. It’s great.

The F/A-18 Hornet brings something a little different to the table. It’s got two engines, a navy-grade undercarriage, and some really fancy avionics for the time. The Hornet was small and advanced, but it cost more both to buy and to maintain. It’s also multirole, and was the first aircraft to shoot down enemy aircraft with missiles and complete a bombing mission on the same sortie in the Persian Gulf War. It’s also got great cockpit visibility.

So let’s break this down:

  • Cost: Viper. Duh. Viper is cheaper to buy, cheaper to fly. Has just the one engine. And it’s the same engine used in the F-15, which is a big bonus if you also operate Eagles, because then you don’t need to add another engine’s parts to the support list. And we do operate Eagles.

Looking at FY98 prices for both (using total program cost for each, because that’s what I happened to find), Vipers will run $26.9M and Hornets will run $39.5M.

  • Cockpit Systems: Hornet. The Hornet has three displays compared to the Viper’s two, and they’re bigger displays at that. The Hornet can run a moving map display too, which is really cool.

  • Engine Power: Viper. Even though it only has one engine compared to the Hornet’s two, the Viper has a lot more thrust, and a pilot can use this thrust to get out of trouble. Or take off quickly.

  • Low-Speed Handling: Hornet. The Hornet is a fantastically high-alpha jet. It performs well at low speeds and high angles of attack, so it’s a great turning dogfighter.

These two previous points mean that while the two aircraft fight very differently, they’re both very capable machines. Practical dogfight capability is a draw.

  • Targeting Pods: Viper. Both aircraft have access to the full range of NATO FLIR targeting pods like LITENING, which use infrared-spectrum cameras and lasers to identify targets. However, the Viper can also mount the ASQ-213 HARM Targeting System pod, which allows for identification of type, bearing, and most importantly range of enemy radars. Accurate range data allows the AGM-88 HARM to be used more effectively.

  • Weapons Fit: Tie. Both aircraft can operate a wide variety of ordinance, with no significant differences between the two.

  • Jamming Systems: Tie. Mostly because both can mount modern ECM pod options, and those are a pain to compare with unclassified data. So we’ll call it a wash.

  • Towed Decoys: Viper. The Viper can be equipped with the ALE-50 towed decoy system. While the bigger Super Hornet can also be so equipped, the standard Hornet cannot.

  • Naval Capability: Hornet. If you want to operate your fighters off of carriers, the Hornet is CATOBAR capable and the Viper isn’t.

  • Twin Engines: Hornet. Lots of Hornet export customers like the twin-engine reliability, since they have big, foreboding, sparsely-populated regions. Like with Naval capability, if this is important to you, the Hornet gains points.

  • Radar Range, Track Fighters: Viper. Based on totally shady open-source materials, I’ve found the maximum radar range to track a small fighter to be 80 km for the Block 50/52 Viper (with the APG-68(V)7 radar) and 72 km for the F/A-18C Hornet.

  • Radar Range, Track Bombers: Hornet. The same source gives the F/A-18C Hornet a maximum radar range to track bombers to be 150 km and the Block 50/52 Viper with APG-68(V)7 radar a maximum tracking range of 140 km.

  • Recon: Hornet. The Viper requires a camera pod for reconnaissance missions. The Hornet can replace the gun and ammo package with a reconnaissance camera package,

  • Pending Upgrades: Viper. In the above, I’ve compared what was flying in 1998 for both aircraft. However, both Greece and Israel were looking to buy some Vipers, and a number of improvements were offered. Specifically, the Apg-68(V)9 radar and removable conformal fuel tanks were available for F-16s ordered in 1998, and both of these features were purchased by the Israelis.

Okay, so where do we come down for Borgundy? We’re going to go with the Viper. The Viper provides excellent multirole capability while also being relatively low cost to purchase and operate. As a bonus, it can have common engines with our Eagle/Strike Eagle fleet. In the late 90s, the Viper is not only super popular in the export market, but it also continued to see development. It does a good enough job at everything we’d like it to do, while also being cheaper than the competition. It’s superior SEAD functionality is a bonus, as we take that mission seriously.

Note that while I picked 1998 as the year for this, mostly because I had price data for that year, the conclusion is similar for other Hornet/Viper matchups of similar vintage. The key differentiators that would push for a Hornet buy are naval aviation (or a naval/land common fighter project) or large remote spaces that would lead to a favoring of a twin-engine design. Neither of which applies for Borgundy, unless the United States wanted to sell one of their (likely conventional powered) carriers to us as well.

Harrier II short takeoff roll reference table

I was looking for this information as part of my still-forthcoming Harrier blog post, and couldn’t find it anywhere. So, here it is: a quick table of Harrier II short takeoff rolls by gross weight and headwind, assuming the Pegasus -408/11-61 engine, standard temperature and pressure (15 degrees Celsius, 29.92″Hg), and 0% datum hover performance.

Gross WeightTakeoff Roll (no wind)Takeoff Roll (20kt headwind)
20000 lb400 ft.275 ft.
22000 lb450 ft.325 ft.
24000 lb550 ft.375 ft.
26000 lb725 ft.500 ft.
28000 lb1025 ft.750 ft.
30000 lb1350 ft.1000 ft.

Sources and Charts

These numbers come from the Harrier II NFM-400 manual. Please don’t share the download link off-site; it’s a fairly large PDF, and we’re pretty shoe-string budget-wise.

The relevant charts are reproduced below.

hover chart

To use the hover capability chart, enter from the bottom, beneath the JPT half of the chart, from the appropriate ambient air temperature. Move up to the 0-degree datum line. Then, enter the chart from the bottom, beneath the RPM half of the chart, from the ambient air temperature. Move up to the RPM limit line. From the lower of the two intersections, move right to the hover performance 0% datum line without following the adjustment guidelines.

The JPTL adjustment values are maintenance-provided and outside the scope of my table. To use them, move up to them rather than to the 0-degree datum line. The hover adjustment guidelines are also out of scope. To use them, after moving right to the 0% datum, follow the guidelines up or down.

For 15C, neither JPT or RPM limits performance. Move across the chart to the 0% hover performance datum and read from there: 21,000 lb.

rotation chart

To use the nozzle rotation airspeed chart, enter from the left using the corrected hover value from the hover chart. Move straight across to the 29.92″Hg datum. Move parallel to the guidelines to the ambient pressure.

From there, move straight across to the takeoff gross weight. Stop at the intersection, move directly downward, and read the nozzle rotation airspeed off the bottom of the chart.

For a 22,000lb gross weight, start at 21,000lb, the corrected hover weight, and move across to the 29.92″Hg datum. Since the pressure is 29.92″Hg, continue moving directly across to the 22,000lb gross weight line. At the intersection, move down the chart to find the nozzle rotation airspeed of about 63 knots.

takeoff chart

To use the takeoff chart, enter from the top left using the nozzle rotation airspeed calculated before. Move horizontally to the 29.92″Hg datum, then move parallel to the pressure guidelines to the ambient pressure. Move horizontally to the start of the temperature guidelines, then parallel the temperature guidelines to the ambient temperature. From there, move horizontally to the curved line to the right. At the intersection, move down to the zero-wind line at the top of the ground roll chart to find the 0-knot takeoff roll. Follow the solid line down the chart to the appropriate line to find the headwind takeoff roll.

To continue the example, enter the chart at 63 knots and move to the pressure baseline at 29.92″Hg. Move horizontally left to the start of the temperature guidelines, and parallel them to the 15C baseline, at about 66 or 67 knots. Move horizontally to the reflector line, then move vertically to find the takeoff roll of roughly 450 feet. Parallel the solid headwind guidelines down to a 20-knot wind to find the headwind takeoff roll of about 325 feet.

Brief Comments

Experience with DCS Harrier suggests that these numbers include a good deal of margin. I have no trouble getting off the Tarawa deck with at least 200 feet to spare, even at loads north of 30,000 pounds. These are, however, the by-the-book numbers.

CAS Aircraft Revisited

I’ve spoken before about CAS-specialist aircraft. I’ve spent a lot of time with the virtual A-10 in DCS, and I’m a big fan of the aircraft. In my heart, I love that gun. But the heart can make us do stupid things. We can’t always trust it. Similarly, the A-10 has saved the bacon of a great many American soldiers in combat. They adore the Warthog, and rightfully so. But they would adore any aircraft that saved them.

We want to know whether or not the Dedicated CAS aircraft is a good buy. Keeping it simple, we’ll compare it to buying more multirole aircraft instead. In USAF terms, A-10s or F-16s. Given that this is 2017, and we have combat data on both, is it worth it to put money towards maintaining the A-10 fleet, or should that money be switched over to the F-16s and F-35s?

The close air support mission is a peculiar one, and one full of contradictory requirements. The A-10 seems tailor-made for the mission, with plenty of armor and a massively powerful gun. It’s optimized for flying low and slow, and this kind of flight profile maximizes the utility of the gun and the ability of the pilot to see things.

That sort of flight profile make a number of assumptions:

  1. Local air superiority has been achieved and can be assumed
  2. Enemy air defense is extremely limited in number
  3. Enemy air defense is gun based or nonexistent

In a conventional shooting war, or even a low-intensity conflict with a sophisticated adversary, we don’t get to assume these are true.1 In a COIN conflict, we get (1) and (2) but we may not have (3). The enemy may have access to MANPADS like Stinger or Igla. As seen in the Soviet experience in Afghanistan, this forces aircraft to medium altitudes, i.e. out of the gun envelope.

Let’s look at the combat record. The A-10 has seen combat in Gulf War I as well as providing close air support as part of US military operations in Iraq and Afghanistan. The first Gulf War is as close as we get to seeing the A-10 in a conventional war. The A-10 was not sent in against the Iraqi SAM systems. But it did see plenty of use against troops of both the Iraqi Army as well as against those of the Republican Guard. The Republican Guard was better equipped and better disciplined than the conscript regular army. The Republican Guard did not have much in the way of MANPADS or other short-range SAM systems, but they fought back with guns. Many A-10s sustained combat damage, and two were lost on February 15, which caused A-10s to be tasked to other targets. While the A-10’s armor usually allowed it to make it back to base, the A-10’s lack of speed was identified as a deficiency that made it more vulnerable to gun hits.

The primary tank-killer for the A-10 in the Persian Gulf was the IR-guided Maverick, not the GAU-8/A. Of course, other aircraft can also carry these Mavericks, and these other aircraft also racked up a respectable tally of destroyed tanks with the AGM-65s. The A-10A had very little provision for precision-guided ordnance2, and so did not use laser guided bombs to “plink” tanks, unlike the F-111. Again it doesn’t take a purpose-built aircraft to carry precision ordnance, and these can be delivered from medium altitude, away from AAA and MANPADS.

Lots of aircraft have done CAS duty in Afghanistan, including of course, the A-10. Again, the big star weapon hasn’t been the gun. It’s the JDAM, which are GPS guided. Also using the JDAM to excellent close air support effect are the B-1B and the B-52H. And many others too, but I’m highlighting heavy bombers because they’re big, high-altitude behemoths that aren’t really “designed” with CAS in mind. But they can do it with modern weapons. As can F-16s, F-15Es, F/A-18C/Ds, F/A-18E/Fs, and just about every other multirole tactical aircraft you care to name. Tactical aircraft give up the giant gun and the armor plate. But there’s a net gain in survivability from more speed because they can evade missiles better, and they can perform the vast majority of modern CAS missions just as well as a purpose built type.

For COIN, one might be tempted to look for savings in aircraft types. These can be provided from UCAVs like the MQ-9 Reaper or from something like a Super Tucano. Both of these will provide more sorties per dollar than the sort of big armored CAS-optimized plane. And if there’s negligible threat, they’ll drop precision guided munitions just as well.

Against a hypothetical, sophisticated opponent with modern integrated air defense systems, all of the above will all require large strike packages to approach any kind of reasonable survivability level, and those aren’t feasible for CAS. Maximum survivability is provided by aircraft with low-observability characteristics, such as the F-35 or F-22. In Desert Storm, coalition air commanders had faith only in the stealthy F-117 to penetrate the formidable air defenses around Baghdad. The alternative to stealth is a big, Rolling Thunder-style strike package with ECM and SEAD escorts, plus fighter escorts. Which isn’t going to be generated for an aircraft to loiter in support of ground forces.

Let’s look at a more modern example: recent events in the Ukraine. Here’s a radar map of the Ukraine.
ukraine air search radar map
That’s a map of all of the air search radars in the region. Have fun with that. And remember, lots of these SAM systems are going to be reasonably modern units that can move. Everyone saw the success the Serbians had by shutting off their radars and moving their air defense systems around to frustrate NATO SEAD strikes. And you can’t sortie your A-10s until you get air superiority and deeply reduce that SAM umbrella.

The gun on the A-10 is a fantastic weapon, but it’s a trifle outmoded these days. If a gun and armor were the sine qua non of CAS, we’d sortie Hs 129 B-3s. With modern precision munitions, the role can be filled by multirole or low-observable-multirole types with no loss of effectiveness. And in hostile airspace where the opponent has some actual air defenses, the A-10 and its ilk are the least survivable types. A mess like the Donbass is begging for low-observability if you want to actually survive to deliver ordnance and live to strike again tomorrow.


  1. Cf. MH 17. 
  2. Rectified on the A-10C.