AVSIM Commercial Aircraft Review

Diamond DA20 Katana

Product Information
Publisher: Aerosoft (for Digital Aviation)
Description:  Single-engine trainer.

Download Size:
51.7 MB FS9 -
58.1 MB FSX

Download & CD-ROM
Simulation Type:
FS9 and FS-X
Reviewed by: David Wilson-Okamura AVSIM Staff Reviewer - March 16, 2007


Small with big views, skinny with long wings, runs on unleaded gasoline, made in Canada: that’s the Diamond Aviation 20, Katana to its friends. (In Japanese, katana is the name of a long sword.) To my knowledge, there have been three Katanas for Flight Simulator: a freeware motorglider by Premier Aircraft Design, a payware upgrade of the same model sold by Abacus, and this one, developed by Digital Aviation and published by Aerosoft (which also handles customer support). In my view, all three versions do a good job of capturing the Katana’s trademark silhouette. Where they differ chiefly is in the virtual cockpit: the other versions are colorful and functional, but the Digital Aviation cockpit is a work of art; I’ll say more about this below.

The occasion for this review is the release, in January, of a compatibility upgrade for FSX. The new product is called “Katana X,” but doesn’t claim to add any new features: except that it works in FSX, little has changed since spring 2004, when the original version was published. That’s too bad, but since we didn’t review the first version, this will be an opportunity for another look.

For this review, I tested both versions. The product description did not lead me to expect any dramatic differences between the FS9 and FSX versions, and in fact I didn’t find any: with a few exceptions, noted below, the two versions are identical.

Installation and Documentation

I installed the download version of both products. Several months ago, Aerosoft moved to a simplified purchasing system, whereby you do not need to reverify your purchase online every time you install. That’s much appreciated, especially now when so many of us are upgrading our hardware to accommodate FSX. After you’ve made your purchase, you will receive a download link and a registration key. Download the software, enter the registration key when the installer asks for it, and you’re done.

Load Editor

Almost. Before you fire up the sim for the first time, you should probably run the Load Editor. Actually it’s more than that. As the name implies, the Load Editor allows you to assign weights for yourself, a passenger, and any cargo. (There won’t be much of that: the Katana is a trainer, not a commuter, so there’s room behind the seat for an overnight bag and not much else.) In addition, the Load Editor can also remove the virtual cockpit (don’t do that, it’s the best thing about the whole plane), remove the GPS display (that’s ok, it’ll still be accessible via a pop-up window), remove the passenger model in the right seat (that’s ok, the Load Editor will replace her with an invisible sandbag), and substitute a low-resolution version of the canopy texture (that’s ok too).

When selected, each of these four options increases the load on your hardware, so by turning off some of them you can increase your frame rates. Finally, the Load Editor also has an option to select “Easy ground steering.” At taxi speeds, the real Katana relies exclusively on differential braking to go left or right. (At higher speeds, the rudder is used for steering, but this only works when you’ve got enough air moving over the rudder surface.) If you have rudder pedals with toe brakes, there’s no problem: this is exactly what toe brakes are meant to simulate. If you don’t have toe brakes, check “Easy ground steering” and the aircraft will steer on the ground like the default Mooney or Cessna 172.

Do you need to read the documentation? Need is probably the wrong word: the Katana is extremely easy to fly. That being said, this is one of the most attractively and thoroughly documented GA planes I have ever owned. For more complex aircraft, everyone acknowledges that you need a long manual, so the good developers usually provide one. But for small planes like this one, with no complex systems, it’s tempting to skimp.

No skimping here: what you get is a version of the real pilot’s operating handbook (POH), including artwork, minus the items that don’t apply to Flight Simulator. In English, the manual comes to 92 pages; in German, it’s the same. So, while the checklists are abbreviated, the charts and diagrams are all there for you to calculate airspeeds, cruise performance, wind components, take-off distances, climb performance, and endurance. The instruments are all described and illustrated, too, from the humble “Carburetor heat” switch to the advanced features of the KX 165A com/nav receiver (which, in addition to tuning radios, can also display a timer and course deviation indicator).

Flight Characteristics

Ideally, the people who review aircraft for Flight Simulator would all be real-world pilots, with at least some hours in the aircraft they are reviewing. I’m not a real pilot, though I have spotted a Katana on the ground at my local airfield. So, take what I say here with a big grain of salt. Perhaps the most important thing to know is that this product was developed with the cooperation of Diamond Aircraft. That isn’t a guarantee of the flight model’s accuracy (which was tweaked, in version 1.2, to give the elevator more authority at landing speeds). Still, it’s a rare thing in the world of Flight Simulator to see this level of involvement by a real-world airplane manufacturer.

The Katana, as has been said already, is a trainer, not a commuter. In this role, its main competitor is the Cessna 150 and 152. Both aircraft are slow, both are small, and both are forgiving of student errors. But while the 152 looks, from the outside at least, like it could have been built any time in the last sixty years, the Katana looks new, even futuristic. There are two reasons for this.

First, it was designed from the ground up with new materials in mind. You won’t see a lot of rivets on the model, because the real thing doesn’t need them: the fuselage and wing are both made of carbonated plastic. This makes the Katana light, and therefore fuel-efficient.

Second, the Katana is descended from gliders. Hence the long wings. Combined with the low weight, this makes for a high glide ratio. (The higher the ratio, the farther an aircraft can glide.) Reports vary on this, but one source pegged the glide ratio for the Katana at 14:1, compared with only 7:1 for the Cessna 150. That caught my attention, so I tested it by setting up a zero wind situation, climbing to 10,000 feet, shutting off the engine, feathering the prop, trimming for best glide speed (again, reports varied for this, but I settled on 74 KIAS), and then tracking distance traveled while I lost 2,000 feet of altitude. This resulted in a glide ratio of 12.2:1; maybe I could have stretched it longer, but for anything with an engine that’s pretty impressive.

Flaps Landing in heavy crosswind

Spins are possible, but this is a trainer, so they won’t happen by accident. Slips are modeled well enough to perform crosswind landings, but the real thing is too skinny for them to be an effective way of losing altitude. So how do you get down when it’s time to go home? With its glider-like tendencies, this could be a problem. The solution is flaps. The flaps on this machine have two settings, take-off and landing. Angled for take-off, the flaps increase lift. Angled for landing, they function like the air-brakes on a glider. With full flaps, the Katana drops quickly, and to stay on the glidescope you’ll probably need to increase power; this sequence will be familiar to anyone who has flown a Beaver, which is an older, much heavier aircraft, but operates at similar speeds in the landing phase.


When the FS9 version came out, almost three years ago, what grabbed most people’s attention was the detailed virtual cockpit. It’s not completely clickable: the heat blower and the circuit breakers can only be operated via the 2D cockpit view or through 2D pop-ups. But how often do most of us use those? There aren’t a lot of gauges in the real plane, but the ones here are all big and clear. The various surfaces are rendered crisply as well.

View switcher Virtual cockpit

If you do fly from the 2D cockpit, there’s a special panel selector to bring up various views and pop-ups. I’m guessing we’ll see fewer of these, as more and more of us switch exclusively to virtual cockpits. But it’s a nice touch all the same.

2D cockpit 2D passenger view

Other nice touches include a working ventilation window on the pilot’s side (an important feature in the real Katana, because it gets hot under that big bubble canopy), a moving passenger in the right seat, a moving “you” in the left seat and, for that lived-in look, some cockpit junk behind the seats. (What’s cockpit junk? A folded chart, a bottle of water, a fire extinguisher, a first-aid kit, a German flying magazine.)

Pop-ups All pop-ups

On a more practical level, the VC also features a number of conveniently placed hot-spots. When clicked, these hot-spots will bring up additional screens and panels. Click on the GPS, for example, and a full-size version (easier to read and operate) will pop up in the lower-lefthand corner of your screen. It’s only the default GPS, but to show it’s a handheld unit, it’s framed by a photo of someone’s hand. There are also hot-spots for the kneeboard, map view, engine panel, and radios. The kneeboard hot-spot is particularly noteworthy: it’s a slide-rule style flight computer, strapped to your knee.

The Crew The Passenger Pilot in Command

I say “your” knee, because while you’re flying in the virtual cockpit, you see your own body, arm, hand, legs, and feet in front of you. If you look right, you’ll also see a female passenger, looking around at the scenery. In the Load Editor, you can omit the passenger to save frame rates. Judging from what people have said on the support forums, it seems that some owners would also like to get rid of the pilot figure. Well, you can’t; he’s part of the aircraft model.

Exterior Model

The Katana has very distinctive curves, especially in the fuselage. Even though it doesn’t handle like a sports car (you wouldn’t want that in a trainer anyway), it looks like one. Someone in my family who is not usually interested in airplanes saw me flying this one and said, “Cute plane!” There aren’t a lot of items projecting from the real Katana’s surface, so the modeler’s main challenge is to get the curves right and make them look smooth. If he succeeds, you won’t notice; it’s only when the curves look stiff that you even remember there is a modeler, at which point he has failed. This model succeeds.

The real Katana doesn’t have many moving surfaces, so the scope for animation is limited. Ailerons, rudder, and flaps all move smoothly, and although the gear is fixed, you can see the struts absorb the force of a landing. When the canopy is open, the book on your dashboard will blow in the wind (it’s also a hot-spot for your kneeboard in FS9, or the map view in FSX). And when you’re on the ground, you can remove the engine cover, tie the wings down with weighted tires, and even unscrew the fuel cap. I’ve already mentioned the working ventilation window in the virtual cockpit, and the canopy opens as well.

Happy face for USA A real flash Tie-down

While I’m still on the subject of visuals, let me mention three additional items. First, the package comes with a total of 18 liveries from seven different countries. (There’s a paint kit available, if you want to make your own.) Second, most liveries include some sort of distinctive cockpit detail: for a Canadian livery, there’s a Canadian flag in the cockpit, and for a U.S. livery, there’s a happy face. (Is there a message in that? You’ll have to ask the developers.) Third, whereas on most aircraft for Flight Simulator, blinking lights seems to “glow” on and off, the ones on the Katana look like an actual flash. Another nice touch.


There are two more variations that I haven’t mentioned. First, some of the liveries come with wheel pants; on others, the wheels are naked. Second, you have a choice of two Rotax 912 engines: the F3 with 80 horsepower, or S3 with 100 horsepower. As you’d expect, the S3 version goes faster, can carry more weight, and burns more fuel. That’s the good news. The bad news, which isn’t really very bad, is that both engines use the same sound set, so you won’t be able to hear any difference.

Wheel pants No wheel pants

This doesn’t bother me -- I assume the real engine sounds are very similar -- but it does bring up the question of sound in general. It’s important, I think, to separate what’s realistic from what we like. I like the sound of a big old radial engine, because I can feel it in my bones and because, in addition to the main thrumming sound, there are other, little sounds that make the whole thing interesting to listen to. This isn’t that kind of engine, or that kind of plane. It’s not big or deep, and it doesn’t produce the odd little noises that makes an engine sound interesting. From an engineering standpoint, those noises are a symptom of inefficiency, and the Rotax is an efficient engine.

What’s more interesting are the start-up noises, including the electrical system. Normally, when I flip the “BATT” switch, I listen for a click and move on to the next item on my checklist. But when I was wearing headphones, I noticed that there was actually a sequence of sounds, albeit very quiet. The same is true on shut-down.


Texture lag on older hardware

More detail usually means lower frame rates. So, what if any impact do all these nice touches have on performance? Before I installed the Katana, I had read contradictory reports: one said it was framerate-friendly, another, that it was hard on frame rates. My experience was positive; frame rates were not an issue and I was using the high-resolution canopy texture.

But what about older hardware? I also tested the FS9 version on a Pentium 4 laptop with 512Mb of RAM and a low-end video card. Here there was a noticeable lag while the cockpit textures loaded, but frame rates were still average; this was with most options turned down or off in the Load Editor, except the virtual cockpit. All in all, a good performance.

FSX Version

FSX has been available on retail shelves now for about six months, and publishers have handled upgrades in a variety of ways. Flight1 has issued free upgrades for two of their aircraft that make them flyable in FSX, but don’t add new features. Carenado has done the same for its whole fleet. RealAir charges for its upgrades, but adds new features. The same is true of Aerosoft’s own Beaver: there is an upgrade charge, but the new plane is really a new product.

That didn’t happen here. If you already own the FS9 version, the update to FSX will cost 8 euros, but there is only new feature that I know of: taking advantage of the new camera system, you can now cycle through four views in the virtual cockpit, and four views outside the plane. This is genuinely useful, not only for making screenshots, but also for interacting with the instrument panel. But that’s the extent of the upgrade.

New views in FSX

Judging from the date stamps, the airfiles seem to have been recompiled, and there are probably some other changes that escaped my notice. According to the German-language support forum on the Digital Aviation website, most of the work for the new version went into the virtual cockpit. I believe that, and it is still a good-looking cockpit. Apart from the new views, though, it’s only as good as the FS9 version from two-and-a-half years ago, and in a few things, it’s not quite as functional.

The VC hot-spots, which I mentioned earlier, are harder to find in the FSX version; half the time they were there, and half the time they weren’t. If there was a logic to this, I never found it, and I’m sure this was frustrating for the developers as well. The other problem is with the kneeboard checklist and reference page. In FS9, this was one of the most complete and attractively formatted kneeboard presentations I have ever seen. In FSX, it’s still attractive, but it doesn’t work. I asked about this on the support forum, and the response from someone at Digital Aviation was “I would prefer to wait for [Service Pack 1 from Microsoft] before reworking the documentation.” I can understand that from a developer’s point of view. But the customer has a point of view, too.

The Katana was a very good aircraft for FS9, and it is still a good aircraft in FSX. Still, one can’t help wonder what might have been. Light bloom, self-shadowing, bump-mapping: these are rapidly becoming standard for FSX payware. You won’t find them here. Granted, the real Katana’s skin doesn’t have many bumps to map -- so let’s think about the cockpit.

Attitude indicator

When the Katana came out in spring 2004, the VC was praised all around, and rightly so. But there was one instrument that, in my view, never looked quite right: the attitude indicator. Unlike most attitude indicators in Flight Simulator, this one lets you adjust the height of the airplane symbol: again, a nice touch that is in keeping with the overall level of quality in the aircraft, and again, one that is genuinely useful when you’re trimming the aircraft at different altitudes and airspeeds. But the horizon ball itself does not actually look round. In real life, the surface of the gauge (under the glass) is spherical; unfortunately, FS9 gauges have to be flat, so the developers have created the illusion of curvature with shadows.

With FSX, this is no longer necessary: it is now possible to have rounded gauges. To see this in action, go to the RealAir Simulations website and look at the screenshots for their newly updated Marchetti SF.260. The gauges are in 3D! The horizon ball is round! For another example of 3D instruments, look at the freeware biplane by Robert Bruce (f2bx1pt1.zip in the AVSIM file library). The state of the art is changing.

Another area where we might have looked for development, if not improvement, was more engine choice. In Europe, the Rotax engine is popular, and it was reasonable to use that engine for the original sim. But in North America, most Katanas have engines made by Lycoming or Continental; for pilots who are training with one of these in the real world, it would have made the simulated Katana more realistic (and therefore more useful) if it had been possible to select one of these engines. This suggestion was made when the original Katana was first released. Of course, implementing it would have meant altering the airfile and recording a new soundset; these are not trifles.

Test System

Core2Duo E6600 @ 2.4 GHz
2 gigabytes RAM
Nvidia 7600GS (512 Mb)
TrackIR 3 with Vector Expansion
CH pedals, yoke
Saitek ST290 joystick

Flying Time:
20 hours


In the last year, Digital Aviation has been universally acclaimed, first for its Piper Cheyenne, and then again for its award-winning Dornier Do-27. The Katana, while not on the same level as these newer products, is still an aircraft to be proud of, almost three years after its introduction.

Who is it for?

The CD-ROM package, which now includes both versions (FS9 and FSX), retails for 30 euros (25 if you don’t live in Europe). The download price is 20 euros (17 outside Europe), but this is for one version only; if you purchase the FS9 version and decide you want the FSX upgrade, it’s 8 euros more.

If you’re training with the Katana in real life, this is probably a small investment (even if your real-life Katana has a different engine). And if you’re not actively engaged in flight training? It looks sporty, it’s easy to manage, and the bubble canopy makes it excellent for sightseeing.


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Diamond DA20 Katana

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The review above is a subjective assessment of the product by the author. There is no connection between the producer and the reviewer, and we feel this review is unbiased and truly reflects the performance of the product in the simming environment. This disclaimer is posted here in order to provide you with background information on the reviewer and any connections that may exist between him/her and the contributing party.

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