• Diamond DA-42 Twin Star From Iris

    Review: Diamond DA-42 Twin Star From IRIS

    By Paolo Baiardi
    19 November 2010

    The DA-42 Twin Star is a four seat, two engine, propeller aircraft. If you are familiar with the Beechcraft Baron 58, this is a rather similar plane, albeit more modern and better looking. This FSX aircraft has been developed by IRIS Simulations, following another similar aircraft, the Diamond DA-40 Diamond Star.

    Simulator Requirements:

    Microsoft Flight Simulator X patched to SP2 standard
    OR Microsoft Flight Simulator X with the Acceleration Expansion pack installed
    OR Microsoft Flight Simulator X Gold edition.

    Purchase and Installation:

    The aircraft has been purchased at the Pilot Shop via direct download. Once downloaded the package has been installed (no remote authentication/registration procedure required).

    Fixes And Patches Available:

    First Impression:

    The Diamond DA-42 is quite good looking and one can easily see the efforts put by the IRIS developers in the design. The VC uses 3D gauges and a slightly modified dual MFD Garmin 1000 system. Pilots and passenger are visible in the external view. The 3D model is really stunning and there are a number of liveries (14) and models (3) to choose from: the standard TDI, the MPP (multipurpose) variant and an UAV proof-of-concept. Cockpit layout is the same for all models.

               

    The manual is detailed in terms of flight envelope and information such as stall speed in the various configurations and flight procedures. The avionic part is less detailed and mostly suggest the user to refer to the standard FSX Garmin 1000 documentation, which makes sense after all. No information about the aircraft autonomy: it is something I would have liked to see. Having seen a few manuals, I would say this one is far better than average.

    No checklist/reference files to be seen in-game: you need to refer to the manual for any procedure or reference data.

    Aircraft Model:

    This is a full FSX/SP2 model. so expect every possible feature being used. The Twin Star is definitively well designed and detailed, both the external views and the virtual cockpit. There is no 2D view, which would be somehow redundant. The VC uses 3D gauges, the background bitmaps are excellent and the instruments are very smooth. The only problem (common to many VC) is that some numbers are relatively hard to read being too small.

               

    Engines And Fuel Management:

    The DA-42 uses two Thielert Centurion turbo-charged diesel engines. Those engines employ a FADEC system, so there is no need to handle fuel mixture and rpm, this is done automatically. Thanks to those fuel-efficent engines, the relatively small DA-42 has a good autonomy, but it is not exactly fast (max speed a tad below 200 knots) and its ceiling is 18,000 feet.

    Engines management is simple: only the throttle is needed, which controls directly the LOAD. RPM is set automatically. There is a fuel indicator on the bottom, however it indicates the fuel available in the main tanks (2x25 gal) and not the additional fuel contained in the auxiliary tanks (2x13.2 gal), which is logically used first. There is no indication of the aircraft range at current speed/altitude, although this can be roughly derived by looking at available fuel and dividing by the fuel flow (GPH).

    By experimenting, I found one can easily achieve a +1200 nm range with relaxed cruise settings flying at VFR altitude (4500'). The Twin Star has been able to cross the Atlantic with an intermediate 1900 nm leg and landing with 5 hours of fuel left. The aircraft was a standard DA-42 fitted with an extra 26 gallons ferry tank. Source http://web.archive.org/web/20080331041108/http://www.diamondair.com/news/08_20_04.php.

    Flight Systems:

    Almost everything is contained in the two Garmin 1000 MFDs. Aside from those, there is a DME receiver (which can operate independently of the G-1000) and an attitude/altitude/airspeed/compass set of instruments. The cockpit is clean and very similar to the real DA-42, with the exception of an 'IRIS quick-start switch' (Control+E equivalent) close to the DME receiver.

       

    The two G-1000 MFDs display a wealth of information. It takes a few times to get accustomed to them, but as time goes by one can only appreciate the flexibility of such systems; I liked for example the possibility to display the air traffic around the aircraft.

    The aircraft is ILS (glidescope information are displayed in the left MFD) and IFR capable. Speaking about IFR, there is a single indicator (CDI) that is used to display either NAV1/NAV2/GPS path info. That means it is rather difficult to fly to a specific VOR intersection as you should continously switch between NAV1 and NAV2. Also, it is impossible to align the VOR radial while flying in AP/GPS mode: the work-around that I have found is simply to switch from AP/NAV to AP/HDG, then align the VOR and then finally switch back to AP/NAV.

    The autopilot switches are located between the two MFDs, together with the radio settings and a group of non-operating buttons.

    Control Systems:

    Nothing really surprising here. A stick, flaps with flaps indicator in the cockpit, trim systems and brakes.

    How Does It Fly:

    The DA-42 is a pleasure to fly: smooth and sensible, quite forgiving as well: You will have no surprises with this aircraft. However, do not expect any aerobatics and do not exceed a 60 degrees bank. Gaining speed, especially immediately after take-off, requires its time, be patient. Also, remember to trim the aircraft for easier take-offs.

       

    Once the aircraft has gained speed, its sleek shape helps to maintain it:

    It can land with speeds as low as 49 knots and it rides very gently down the glidescope. This is an example of ILS landing with autopilot at Nice airport, France. The CDI indicator works as localizer (as you can see, its label has changed from NAV1 to LOC1) and the small green diamond on the right indicates the correct altitude to stay on the glidepath. With the autopilot set in APP mode, all you have to do is keep the green diamond in the center using the throttle. The lady in the back shouldn't be too disappointed of the landing!

           

    Minor Issues Or Glitches:

    • The [OBS] in the left MFD key does nothing. It is always possible to rotate the NAV/LOC needle.
    • Even if an engine is shut down in flight, its propeller keep rotating (at the same speed of the other)
    • Sometimes the engines do not start (in the "cold and dark" setup). Resetting the fuel feed switches off and on solves the problem
    • The aircraft creeps forward at idle power unless brakes are applied / brakes aren't that powerful. This has been in partly fixed by hotfix 1.05

    Major Problems:

    • The aircraft does not stall flying below stall speed when landing (it keeps floating over the runaway). Issue solved by hotfix 1.05
    • The aircraft has direct-injection engines however you may experience power loss in adverse weather conditions. There is no "carburator heat" switch in the cockpit (this is correct, since there are no carburetors) but you need nevertheless to switch the 'carburetor heat" on to keep the engines running. IRIS has been notified of this, but it appears to be an FSX modeling issue.

    IRIS Support:

    I contacted IRIS support twice for problems related to this aircraft. IRIS has issued a patch (1.05) that has fixed one of the major problems I complained about (aircraft not stalling due to ground effect) and for the other problem I found (carburetor heaters required in a fuel-injected engine) there is still no solution. I have had a good impression of IRIS support altogether, and this is yet another reason why I will recommend this aircraft.

    Note: you have a direct reference to the aircraft version in the post-it attached on the cockpit, a nifty touch:

    Who Could Appreciate This Plane:

    This is a plane for GA aficionados: good looking, smooth flight handling, easy to land, with a good autonomy and a 'glass cockpit'. If you like cross-country flights, plan a round-the-world tour or if you are making your career with FSPassengers X and are about to switch from the Cessna C-172 to "something bigger" this could be a good choice. If you are a beginner, you'll find the transition to the Twin Star easy and if you are an intermediate FSX user, you'll like the possibilities offered by this plane. An expert FSX user would probably find this plane a bit 'easy', but still like it.

    Conclusion:

    Extremely positive. You can feel the effort the IRIS team put into this aircraft. It isn't perfect (as anything man-made) but it is very, very good. You have a beautiful design, several textures to choose from, a detailed VC and a good manual to refer to. Clearly there are a few glitches here and there (mentioned above) but the IRIS Support wasn't hiding behind a finger and they worked to fix them. We have to remember that issuing patches is a pure cost for a software house as 1) the product has already been sold so there isn't any additional revenue 2) the time required to fix and test those bugs is time which could be instead be invested in making new products to generate new revenue, so fixing bugs deserves a lot of credit.

    Test System:

    Intel Quad Core i7-920 @ 2.67 GHz
    GeForce GTX 480
    8 Gb RAM
    3 x SATA HDs
    Windows 7 64bit
    FSX Acceleration, REX2/GET/UTX, ENB Series Mod

    Paolo Baiardi
    paolo.baiardi@gmail.com

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