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Aircraft Review : Cessna 337F Skymaster by Thranda Design

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Aircraft Review : Cessna 337F Skymaster by Thranda Design


Thoughout the history of aviation there have been many different concepts...  fuselage shapes, wing designs, power sources. But in the one area of multiple engines, there is the Twin Engine mounted wing configuration, or commonly known as "Twins".


Several twins however use a very different concept, one was the wartime Do 335, another and another was far more famous aircraft the Cessna 337 Skymaster.


The concept is called push-pull configuration in that has a combination of forward-mounted tractor (pull) propeller, and backward-mounted (pusher) propeller. In the Cessna 377's case it was two Continental IO-360-C air-cooled flat-six piston engines, 210 hp (160 kW) each, producing a combined 420hp, plus the unique "Twin-Boom" tail arrangement to accommodate the rear (pusher) engine/propeller. Basically the 337 was a standard Cessna forward fuselage, but with a totally different concept at the rear.


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The first Skymaster, Model 336 Skymaster, had fixed landing gear and initially flew on February 28, 1961. It went into production in May 1963 with 195 being produced through mid-1964.


In February 1965, Cessna introduced the Model 337 Super Skymaster. The new model was larger, and had more powerful engines, retractable landing gear, and a dorsal air scoop for the rear engine. (The "Super" prefix was subsequently dropped from the name.) In 1966, the turbocharged T337 was introduced, and in 1973, the pressurised P337G entered production. Cessna built altogether 2993 Skymasters of all variants, including 513 military O-2 versions.


Thranda Design are on a roll. Last year in 2022 they released two Cessna's, Cessna 208 Grand Caravan, then later a Cessna U206G Stationair. Now another Cessna joins the fleet in a Cessna 337F, the push/puller icon.


This C337 is not the first 337 in X-Plane, that distinction goes to Carenado's Cessna C337H Skymaster v2 HD Series, back in 2013, an iconic and much loved aircraft (by me anyway)...  I loved the thing, and you can see on how good it was even a decade ago in the review above.


Thranda Design also had a lot of input into that aircraft, as they also managed back then the Carenado fleet for the X-Plane Simulator, so they already know the aircraft intimately.


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No matter how many aircraft you review, you are still amazed at the quality and detail you get today in simulation. Once you flew models (or modeled aircraft), but today they are realistically miniature aircraft in almost every perfect detail. Every panel, appendage, rivet, screw and the overall shaping is perfect, or perfection, inlets show a mock Continental IO-360-C, but the engine is not accessible (Unlike the U206G).


Glass is perfect, a green tint (more visible internally) with wear speckles embedded, it looks and feels nicely authentic.


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The twin VHF roof mounted aerials are distinctive on the C337, as is the large cooling inlet for the buried rear engine. Note the top oil filler cap, nice detail.


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The support strut for the tail booms is interesting. It is plastic or early form of glass-fibre to save weight, behind the strut in the boom structure is a sump tank.


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Flaps are divided on to each side of the boom, so in essence there are four sections. Detail again is excellent, note the boom fairings around the flaps detail...  there are three flap degrees.


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There is the beautiful cambered detailing of the wing tips, that defines the chord. And you have the choice between "Icing Boots", or a blank leading edge.


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The rear twin booms, with the large central horizontal stabiliser is huge, with built in elevator and trim tab. Each boom has each internal left and right rudder cables and the right hand boom carries the trim cable, the left boom the elevator cable...


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...  tailstrikes are common, rare that any C337 has no tail damage, both the upper and lower assemblies here are excellent detail. You can't just swap around a Continental IO-360-C engine either...  the rear has a very different load bearing (push) to the front's (Pull) bearing (again made tougher to absorb the higher loads). Note the rear engine cooling flaps (open).


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The landing gear is basic in a complicated way....  the wheel assemblies quite basic, hub and arms, but complicated in that they have to fold up into the fuselage, the nose gear rotates sideways on retraction, the rear spindly legs also have to contort to fit in the rear bays. A lot of owners take the rear gear doors off, as maintenance wise they are a pain (an option here?).


Early 337 models used a manual hydraulic floor pump to raise and lower the gear from 65 to 73, then it was converted to two ECSs in the model, each with a 5.5-volt BEC. The front BEC powers a receiver in the fuselage (behind the front engine ) that operates the retracts, doors, nose wheel steering, right aileron and right elevator. The second receiver is in the wing and is powered from the rear ESC. The wing receiver operates the left aileron, left elevator half, both rudders and both flaps.


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As noted the gear in detail is very well done by Thranda, all assemblies and tyres are first rate, even good enough to spend time and admire the work. Because of the type of undercarriage on this aircraft, there won't be any of the usual Thranda addon features like; Tundra Tyres, Ice-Skis and Float/Amphibian versions. There are a few 337 float conversions out there, but they are very rare.


If you want to call it the "Arse End" or "Rear Belly" of the aircraft, the lower rear fuselage is really well detailed with great well designed vortex generators, to create a smoother rear (breakaway) airflow from the aircraft with the powered propeller above.


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From on-wards with the 337G Super Skymaster version, there was a split airstair entry door, like on the Carenado 337H, great for leaving the upper window open in flight. Here though on the "F" model with Thranda, it is the earlier single entry door, the only other opening door is the smaller cubby door for baggage rear lower right side.


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Only a single door entry to a six-seater aircraft, so it is tight in there with this seating configuration. Usually you would only use the seats, and so where do you put the baggage? usually on your lap, so the six-seater configuration doesn't work.


In a real 337 your on top of each other, so it's small, really small. Note the excellent seating, the lower base and legs are really well designed... nice to look at as well.


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Unlike most Cessna's, the rear of the cabin doesn't taper away, so it is really inside a tall box. The rear engine which is set just behind the rear bulkhead is close to the rearmost passengers, it is known to be noisy as well.


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Cabin is tailored in a mixture of creams and browns, again reflecting it's pre-70's age...  the headlining has a zip to the rear, again nicely done, with the front high set Fuel tank opposite selectors, for the front and rear engines.


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Forward and the instrument panel is dominated by the huge pedestal, with six levers (THROTTLE, PROP and MIXTURE) for the two engines...


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...  front side windows are huge and past the front line of the wing leading edge...  and reason why most C377's are used for observation, e.g. the Cessna O-2 Skymaster (nicknamed "Oscar Deuce"), fire and maritime observation patrols. Front side window (sometimes known as the paperwork window) opens as does the ash tray (it was the 70's). The Pilot's window is fixed, but the door window can be opened.


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There are two choices of yokes, "Slim" or "Beefy", the beefy version is the same large centred yoke from the Thranda U206G, but it works in here.

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Looking at the instrument panel, there is one glaring omission between the Carenado 337H and this version...  that lovely green buttoned Autopilot panel...  disappointed, as it was a huge feature on the earlier aircraft.




Otherwise they are very much alike. As this aircraft has the "Dynamic Panel" system from Thranda, there are no set instrument arrangements, as we shall see that aspect later.


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Two areas on the instrument panel are standard...  the excellent twin engine gauges with Manifold Pressure and RPM. A Fuel Flow (FF) and EGT (Exhaust Gas Temperature). The highlight on this side is the engine dials that show (top row) fuel gauges (two tanks, 46 GAL each), OIL pressure. (lower row) CYL head temp, and OIL temperatures. Other dials cover SUCTION, Air Temperature and Volts (amperes).


Left lower panel has the VOLTS/BATtery (alternators), IGNITION/STARTERS , Instrument lighting (Flood/Post), Cowl Flaps (Front/Rear) and main electrical switchgear; MASTER, AUX PUMPS, ANTI-ICE, AVIONICS, (External) Lighting.


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The (hydraulic) gear selector is by the excellent large and handy (pitch) trim wheel. Park brake is a simple push/pull knob lower.


The six lever; THROTTLE, PROP and MIXTURE pedestal is large and excellent, with a yaw (Rudder) trim wheel set below. Lower is a ADF Receiver panel.


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Left side panel is a fully active "Circuit Breaker" (Fuses) panel. In the opening glove box are the happy faces of the "Thranda Team".


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Thranda's Menus are very feature rich and highly detailed. There is a popout TAB under the arrow lower left, that can be (mouse) scrolled to hide it, that is if you don't like these sort of items crowding your screen (I don't). The Menu system includes the "Dynamic Generation Series" or DGS, a Thranda speciality feature that takes full advantage of X-Plane's flexibility for in-sim, real-time modifications.


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As noted the "Menu" Tab (arrow) is far left middle of your screen, this will activate the Pop-Out Menu... The Menu has seven menu tabs in; GENERAL, LIVERY, WEIGHT/BAL, CAMERA, AUDIO/SLEW, PANEL and MISC (Miscellaneous)


Menu - General

The menu "General" sections covers quite a lot of options, the layout is highly detailed and very comprehensive.


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General menu selections cover; Electric Tug, Window and Instrument Panel Reflections on/off, Startup Running on/off, GPU on/off, Cargo Pod on/off, Chocks and Brakes.


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Three selections placed right cover group items, but any one item can be also accessed via "Click Spots" and can be individually selected or hidden via the aircraft graphic. "ALL COVERS" will select engine inlet/outlet covers and pitot cover, "ALL TIE-DOWNS" for rear fuselage and wing tie-downs and "ALL DOORS" for both the cockpit door and rear cabin doors. All EXT - External Lights can be switched on and off as can the ALL INT - Internal lights.


The "Electric Tug" that can be used to move the aircraft around on the ground via your joystick (left,right-forward,backwards). Static Items include Ground Power Unit, Engine Inlet covers, Pitot covers and Tie-Downs


Cargo pod is nicely detailed and comes with a single opening door, you can also add in the amount of baggage according to weight.


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The excellent "Checklist", can also be found on this tab. Which is the same as the Thranda U206G system...  in the red, or the checked green choices you used on the other Thranda aircraft, and not the single white text on the Caravan. On some pages it notes performance and flying tips.


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You can have checklist pop-up or in a window mode and thankfully you can move it, and scale it even from the very small to the very large size. The two lower arrows give navigation around the checklist pages. The action detail and hints in the lists are simply excellent and the checklist is fully detailed from Pre-Flight to Shutdown. And to reset, it is done at the end by switching all the green completed checklist back to red.


Menu - Liveries

Second Menu option is "Liveries", there are two options here with the first being "PAINTED LIVERIES". There are altogether 8 liveries or two blank (or DynamicLiveryResources/ZZTemplate) and six designs, and all are of extremely high quality and creative flare with the package. Thranda house is default.


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Dynamic Liveries

Not happy with any of those designs, then why not create your own livery! 


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With their earlier releases of their Caravan and U206G. Then Thranda introduced a clever feature of a way to design your own livery. This is done by switching from PAINTED LIVERIES to DYNAMIC LIVERIES (Arrowed).


Two liveries are "Dynamic" in resources (White)...  another New feature is the (Quick) selection of Dirt (Ext) Externally, Scratches and Dirt (Int) Internally. Via three percentage selections you can adjust the amount of Dirt, Scratches and Dirt Int on the aircraft (0%-255%) and apply it instantly.So you can have either a pristine or a very grubby aircraft with just a twirl of the numbers. This can be applied to any of the liveries.


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You have a menu to select on the right that can colour a certain part of the aircraft, like the Roof, Wing, Tail or Wing tips. Select which one you want and then adjust the RGB colours for that certain area, it looks hard but you can easily design a very nice livery in about twenty minutes...  the selections of Dirt (Ext), Scratches and Dirt (Int). Metal(ness) and surface Rough(ness) can also be added or adjusted as seen earlier...


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When done you can "SAVE" or ADD the livery and then "APPLY" it to the aircraft. The conversion takes a few minutes, but the results are excellent and in your own design...  There are already 30 preselected selections in their various designs, all which are very good, and like noted you can add in your own version to the list. New to the Dynamic Livery application is ERA options in "Modern' or "Classic". Of course taste is optional...


Here I changed the aircraft registration to an Australian Rego (VH-337), because I didn't like the Australian default aircraft...  cool.


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Menu - Weight/Bal


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The C337F also has a great Weight and Balance menu. Lbs and Kgs which can be selected and changed via the toggle Lbs/Kgs (arrowed).


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Fuel can be added, and the amounts are then shown and are also adjustable as well in the menu (above). Pilot, passengers and cargo can all be set for individual weights and all selected via a scrollwheel...  and then all of the CofG (Centre of Gravity) parameters are shown on a graph. Go too far or too heavy and the CofG goes red (arrowed). When done you can Save the Configuration and then later re-load it, or press Load to add in the set weights. Overall it would be nice to have set of loading formats of different configurations, it is slow work setting them individually.


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Once you go over a certain weight, you will then get two pilot's in the front seats, but no rear passengers. Pilots (Female/Male) are switchable. Note if you turn the aircraft power off, the pilots will again disappear.


More cabin options allows you to hide each of the four rear seats, via the small x tickboxes, if the weights for each seat is still set in place (or adjusted) then the area is replace by baggage. This makes for a very versatile cabin.


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The Cargo Pod can be added or removed on the MISC Tab. This then adds in the Cargo Pod weight options on the right.


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But obviously there is a compromise? If you want a full passenger and baggage load, then you can't have full fuel tanks, as the excess weight takes you over the weight and the CofG limits. For six (light) passengers (with maybe a bag thrown in) then can you have your full tanks and the range and not go into the red. You can also really pile a lot into the rear cabin two sections, and all the baggage is of very high quality.


Menu - Camera


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There is a camera feature under the menu "Camera" selection. The left side of the panel is the "Walkaround" views, just pick the dot viewpoint you want to see to rotate around the aircraft. To the right is the default views can be selected via a menu, or press the keypad to select the view with most of these internal viewpoints. The FoV or Field of View is adjustable via a slider.


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Menu - Audio/Slew


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Sound can be adjusted via the sound menu. There are seven slider selections with: Master, Aircraft External, Aircraft Internal, CoPilot, Radios, Environmental and User Interface. One other sound setting is on the Flap panel...  As noted, on the right and left of the panel you get the audio simulation of an active noise canceling headset, which is seen as wearing a headset. Sound quality is beyond excellent as it is a built in audio mixer, so you can individually control the audio channels in real-time and you can adjust the volumes while hearing them play.


Slew mode allows you to manually move the aircraft around in a disconnected X-Plane space. It functions by temporarily overriding the various aerodynamic and physical forces on the X-Plane settings, it is to allow the user to reposition the plane as desired. This feature is however highly touchy and it is mostly used with the floats option (not really coming to the 337), but for use on the Caravan, Thranda Beaver and PC-6).


Menu - PANEL

The sixth "PANEL" Tab option allows you to adjust or change the instruments and dials.


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Scroll the "Panel Preset" number (arrowed) to see the extra six preset layouts (seven choices in all). Sometimes to restart you have to click to "Apply the Settings" for the GPS units.


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Panel features include; Bendix King KFC-225, and the noted Aspen EFD 1000, KR 87 ADF Radio, Garmin GMA 340, Garmin GTX325 Mode C Transponder, BendixKing IN-182A Weather Radar, S-Tec Fifty Five X Autopilot and the usual GNS 430/530 PS/Nav/Comm units. A EDM 780 Digital EGT (shown lower) is also available. And there is a special 3d bezels for the insertion  of RealityXp GTN 750/430 units if you own those two addons (arrowed above).


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Here is featured the EDM 780 EGT display, a replacement for the twin EGT gauges, the instrument pops-out as well.


The Aspen EFD 1000 is a self-contained multifunction digital display that is divided into a Primary Flight Display (PFD) in the top half, and an Electric Horizontal Situation Indicator (EHSI) in the lower half. As EDF 1000 systems go it is not as highly featured with the GPSS, MAP,  360 and Menu functions all not simulated...  all the lower NAV1/NAV2/GPS selections are however available, as is the TPS (Tapes) see/hide option with the MIN (Minimums) selectable as well. and the PFD can be reversed with the EHSI. The EFD 1000 here can be used with the S-TEC Fifty Five X Autopilot.


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Customising the panel to your own personal layout is just as easy. Just select the "3D EDIT PANEL MODE" (arrowed) that gives you access to all of the 53 individual instruments and avionic units...  There are some great options including Aspen EFD 1000, S-TEC 55x Autopilot, Angle of Attack gauge and so on...


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For those that find instruments are not to their liking in say, "I wish I could move that altitude meter just a bit more to the left", then here you can simply adjust that instrument, or even swap the instruments around the panel to your liking. You can even adjust the brightness of the instrument. Optional is to select the type of GPS unit you want GNS 530/430 via the "INSTRUMENT" selection.


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When done you can "ADD" (or Duplicate) a new "Preset", and then "SAVE" that new layout Preset (Preset /6).


So basically you can start off with a completely blank instrument panel and then create your own unique or personal instrument layout if you have the time and patience...  and you can have up to or save 14 different instrument layouts. It is however very important to restart X-Plane to lock in the new instrumentation layout before flying.


Currently the optional "Panel Background" choice (colour) is not available on the 337F, like it was on some other Thranda DGS systems.


Menu - MISC

The Misc (Miscellaneous) page has four panels that cover Yoke Type (Chunky or Slim) ,De-Ice (wing) Boots, Cargo Pod (Normal or Cargo), Pilots (Option 1 Female, Option Two Male) and DynaFeel.


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"DynaFeel" on the right is a system that dynamically adjusts the rate at which the controls deflect. It is  based on airspeed and how much the control is deflected. This means the controls will feel light and responsive at low speeds and with small deflections, but will get progressively heavier as the airspeed increases.



Flying the Cessna 337F Skymaster

The 377F is an odd aircraft because of it's push/pull configuration. The front is standard, the rear installation is everything but. In the cockpit it is bit like wearing a very heavy backpack, you know it's there but you can't see it. And that heavily enclosed rear installation causes problems as well....  mostly the heating.


So the aircraft is expensive to run, maintenance costs are notably high and so are the insurance premiums. This puts of a lot off buyers, which is a shame as the unique configuration is a very good flying machine.


You have to start the front engine first, to push cooling air into the upper vent to keep the rear engine cool...


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...  even when you have started the rear IO-360-C air-cooled flat-six piston engine, you have to move forward quickly. More air is required by movement via the twin open cowls on the rear, the nose engine has the same cowls under the aircraft, but it also has the forward nose inlet.


Sit there for a period of time and it could get very expensive... quickly. And yet you need the "Temps" to come up before moving, my trick is once the needles are showing rear temps, then go...  the taxi to the runway will do the rest. And this highlights the biggest point in flying the C337, your eyes are never (ever) far from those Temp gauges, you can't see or feel that rear engine, so the gauges are your eyes and ears to what is happening back there.


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Sounds when running are obviously different. Although both IO-360-C engines are the same, however they sound very different because of their different locations and installations. So you get Individual sounds for the front and back engines, with different sonic characteristics.


Combine that with 3D 360º audio effects, including "blade slapping" sound when view is perpendicular to prop, and you can even hear the turbulent air feeding into the rear prop. Also the "beats' are all there with the precise beat frequency for each section, to minimise "muddy" transition sounds, in other words the running "ticker, ticker", sounds at idle, the same as any Continental piston engine, but sonically coming at you from both ways...  it's all very good.


It is up to you if you want to taxi on one engine, or both...  personally you don't need the rear engine to taxi, as the front IO-360-C has more than enough power...


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...  with no stress yet on the rear engine it helps in keeping it a bit cool(er). I use a Yaw setting on my Joystick to steer, but rudder inputs, in mostly the right rudder will fine tune the taxi line, even slight turns like this with the rudder input are easily available...  on the ground the 337 is excellent, nice power inputs, that slack off when you reduce the power, so all it's lovely on the ground.


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Cockpit in detail in X-Plane 12 is realistic as it gets, Simulation 2023...  the silhouette is the iconic C337.


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Because of the unique engine arrangement and rear fuselage configuration, the rear engine creates instant aerodynamic flow over the huge horizontal stabiliser and elevator, so the pitch feel is there from the word go...  so you have to be aware in the way you use the pitch earlier than usual. On the real 337, the pitch trim is motorised automatically to compensate for the extra elevator pressure loadings, and will work (trim) from the moment you leave the runway. The rear propeller is highly exposed as well... thrown up rocks from the rear wheels can cause grief (in other words expensive repairs), and you have to leave the runway cleanly, or not a too pitched up, in not catching the ground sort of skill... obviously you can't see it at all.


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But the unique push/pull engine configuration also works for you in not creating any (depending on the power outputs) yaw, as the inline counter-rotating propellers give no directional thrust pull, so there is no asymmetrical thrust or yaw to the power output of the propeller, basically you go straight down the runway with no corrections or slight rudder corrections...  and fast you do go!


I usually bring the front (puller) up to 90% power, tracking right I then bring up the rear (pusher) to match it...


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...  remember the rear engine operates in the disturbed air from the forward engine, which may reduce its efficiency to 85% of the forward engine.  Basically the 337 is a small aircraft with two engines on it, so it GOES...   well "like shit!".


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At 100knts you break with the ground, slight pull back with the yoke, and once clear then a 10% pitch to climbout...  you have ton's of power behind you, so the 337 will climb-out very easily...


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Rate of climb is 1,200 ft/min (6.1 m/s), but you can do a 1,000 fpm comfortably... now for the big theatrical production!


First the gear doors open, then the nosewheel will twist sideways to fit into the front wheel-well...


Thranda_C337 - V2_Flying 20.jpgThranda_C337 - V2_Flying 21.jpgThranda_C337 - V2_Flying 22.jpgThranda_C337 - V2_Flying 23.jpg


...  from the rear the fine limbed gear has to then contortion to fit in what is basically four rear bays.


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The animation work here is difficult and very complex, but Thranda have done an excellent job, in getting it perfectly correct. Then you have a nice clean aircraft. Note... the gear lever will go up, then return to the centre position once the hydraulics have finished the procedure.


Thranda_C337 - V2_Flying 28.jpg


Once cleaned up, the one thing you realise very quickly, is that the 337F is one amazing aircraft to fly. Maybe it is huge wing arrangement, and twin boom tail, but it is steady as a rock and smooooth, easily trimmed, and can then bank to your will...  ohhh it's "so good".


Thranda_C337 - V2_Flying 29.jpgThranda_C337 - V2_Flying 30.jpgThranda_C337 - V2_Flying 31.jpgThranda_C337 - V2_Flying 32.jpg


You can bank to the extreme, say 80º/90º (See Redbull video), and the 337 will take it all in it's stride, but note the loss of height, if you are doing these sort of very angled manoeuvres.


Thranda_C337 - V2_Flying 33.jpg


The numbers... Maximum speed: 199 mph (173 kn, 320 km/h) at sea level : Cruise speed: 144 mph (125 knots, 232 km/h) at 10,000 ft (3,050 m) (econ cruise) : Range: 965 mi (839 nmi, 1,553 km) : Service ceiling: 19,500 ft (5,945 m)


Thranda_C337 - V2_Flying 34.jpgThranda_C337 - V2_Flying 35.jpgThranda_C337 - V2_Flying 36.jpgThranda_C337 - V2_Flying 37.jpg


A lot of operators use internal tanks on the 337 for on-station flying (fishing, fire, maritime patrols etc) so the range is expandable.



Internal lighting is quite basic, but effective. There are only four adjustment knobs; POST (those little lights on the instruments), FLOOD, EL PANEL and ENG RADIO.


Between them you get a full lit panel with red highlights...


Thranda_C337 - V2_Lighting 1.jpg


...   a Black&White panel, or a Red panel


Thranda_C337 - V2_Lighting 2.jpgThranda_C337 - V2_Lighting 4.jpgThranda_C337 - V2_Lighting 3.jpgThranda_C337 - V2_Lighting 5.jpg


Last adjustment is for the lower left instrument panel. In the rear you have four spot lights that you can adjust the beams, the roof Fuel Switches are also lit up...  but missing is a forward flood cockpit light, and you seriously notice the absence?


Externally it is pretty basic as well, Landing/Taxi lights in the wings, navigation and strobe lights on the wingtips, a right tail beacon and white navigation lights on the twin tails. There is also a nice left side Ice-light on the wing.


Thranda_C337 - V2_Lighting 6.jpgThranda_C337 - V2_Lighting 7.jpg


Notable is cooling as already noted. Once airborne you can close the cooling vents forward and rear, this nicely cleans up the aircraft. But there a need to keep all eyes on all the temperature gauges. It becomes a bit of a game on how long (or how far) you can go with the vents closed, once the needles are touching the red zones, you are out of there...  switches are lower pilot panel right.


Thranda_C337 - V2_Cooling 1.jpgThranda_C337 - V2_Cooling 2.jpgThranda_C337 - V2_Cooling 3.jpgThranda_C337 - V2_Cooling 4.jpg


Cruising you can easily see the 337F's main outstanding elements, as a stable observational platform. You can understand why the US Army grabbed a load of 337s for this purpose. I wouldn't use the aircraft so much in carrying fare paying passengers, it's too cramped and even too noisy to put into commercial service, but for two (Pilots) and a load of gear, it is perfect.


Thranda_C337 - V2_Flying 38.jpg


A quick look at the Orbx Brisbane City pack... Brisbane is 70 kms north of here and my local state capital. It comes back to my original argument, create the inner city and the autogen will do the rest, it works fabulously well here, as does the complimenting Orbx YBBN Brisbane international...


Thranda_C337 - V2_Flying 39.jpgThranda_C337 - V2_Flying 40.jpgThranda_C337 - V2_Flying 41.jpgThranda_C337 - V2_Flying 42.jpg


YBBN Runway 01L is all brand new, just completed only a year or so back...  time to check it out.


Thranda_C337 - V2_Flying 43.jpg


Two things are very apparent on the approach, first the 337F's lift is impressive, those wide wings and horizontal stabiliser (with added thrust on it, mind you) keeps you very steady, almost static in the air, which means manoeuvres can be easily controlled. So the old adage applies here, the Skymaster is a very "Sweet" aircraft to fly. Second is that once you reduce the speed on approach, even at 120 kts, off goes the gear alarm? it feels far to early, not even in the flap white zone, so you have to drop the gear early to just "shut it up".


Thranda_C337 - V2_Flying 44.jpgThranda_C337 - V2_Flying 45.jpg


I think the alarm is there and early (still a bit too early though), because it takes the gear a very (very) long time to unfurl and lock down, it feels ages from when you drop the lever to when the green light comes on...  notably I opened the cooling vents before landing, and instantly all the temp gauges drop.


Thranda_C337 - V2_Flying 46.jpgThranda_C337 - V2_Flying 47.jpg


Flaps are 4 phase 3 degree movements; UP - 1/2 - 2/3 - FULL, get the speed right and there is simply no ballooning, just slight drop of speed, even down to the FULL setting, the Skymaster will stay calm and collected with no fighting of the aircraft...  critical on approach.


Thranda_C337 - V2_Flying 48.jpgThranda_C337 - V2_Flying 49.jpg


Over the threshold and your in the 70 knts range, perfectly stable... 


Thranda_C337 - V2_Flying 50.jpgThranda_C337 - V2_Flying 51.jpg


...  60 knts in the flare. The flare has to be perfect, as you are very aware of that rear propeller hanging down. Slight 5º-6º degrees to keep the nosewheel slightly higher than the rears, then let it down.


Thranda_C337 - V2_Flying 52.jpgThranda_C337 - V2_Flying 53.jpg


When the rears touch you bring down the nose carefully, the slow landing speed and excellent lift really helps here to get it right.


Thranda_C337 - V2_Flying 56.jpgThranda_C337 - V2_Flying 54.jpgThranda_C337 - V2_Flying 55.jpg


Then back to taxiing with the rudder pedals.


It's a long taxi from YBBN runway 01L/19R to the GA area, and i'm watching those temp gauges like a hawk... but I get there. BNE needs to create a shorter taxi route to 01L/19R from the GA Area, which the area is actually close to?


Thranda_C337 - V2_Flying 58.jpgThranda_C337 - V2_Flying 57.jpg


I finally get there...  notable with the engines now shutdown is the active variable-pitch on the propellers (PROP levers) in being feathered, it is all very well done here by Thranda, authentic, realism... take your pick but still great.


Thranda_C337 - V2_Flying 59.jpg


Thranda_C337 - V2_Flying 61.jpgThranda_C337 - V2_Flying 60.jpgThranda_C337 - V2_Flying 62.jpg


Although a very different configuration from the usual, the 337F is actually a very nice aircraft for a pilot, you never oddly fight it, it is SO stable (that word again), a dream in all the aspects of manoeuvres in the air, trims nice, just "Bloody" feels nice as well.


All round this a great aircraft, different in most aspects, but that is also it's attraction for a really special simulation.



The Cessna 337 is a very unique aircraft in the history of aviation. It is only one of the few created and built in the Push/Pull configuration, or a forward PULL engine and a rear PUSH engine, to accommodate the rear push engine it has a two boom and twin tail arrangement, with a standard Cessna fuselage and forward engine layout. Yes it's totally unique, but it works.


Last year in 2022, Thranda Designs released the Cessna 208 Grand Caravan and the U206G Stationair, those aircraft in the series are now joined by the Cessna 337F, after Thranda's earlier more rugged utility aircraft Series. This aircraft is powered by two Continental IO-360-C air-cooled flat-six piston engines, 210 hp (160 kW) each, producing a combined 420hp.


Thranda Design are one of the best developers in X-Plane, their history and quality is legendary. So that quality build and detailing is always going to be significant from the start, and so it here... exceptional. In every area and detail, modeling, fine details, glass and the interior materials.


Menus are also excellent with menu tabs in; GENERAL, LIVERY, WEIGHT/BAL, CAMERA, AUDIO/SLEW, PANEL and MISC (Miscellaneous), that covers all the options and including sound, weights and balances also including graphs, walk-around and camera options and general static elements including GPU, chocks, pitot covers, two pilots (Male/Female) and tie-downs.


Sounds are excellent with High fidelity, multi-track sounds with smooth, finely tuned transitions, amazing atmospheric effects, different sonic characteristics (with the engine arrangement) and 3D audio effects, including the "blade slapping" sounds and the aerodynamic interaction effects between front and rear prop. Internal sounds are however a bit too low compared to the external.


Thranda always comes with a high range of clever and unique features to give the user a lot of personal options. Known as the "Dynamic Generation Series" or DGS, this is a Thranda speciality feature that takes full advantage of X-Plane's flexibility for in-sim, real-time modifications. Here you can change the actual livery to your own designs, but build the instrument panel to your own liking as well, including options of the Aspen EFD 1000 glass instrument and a special 3d bezel for the insert of a RealityXp GTN 750 and GNS 430 units if you own those add ons.


Comments include, Tricky to start, Tricky to keep cool, and the unusual undercarriage bans a lot extra features in Tundra Tyres, Ice-Skis and Float/Amphibian variants. Lighting is good, but there is no overhead cockpit flood light, four rear spots are also small, in making it a dull night cabin, instrument pane is however good, but you feel you need more adjustments. Missing also is that valued green buttoned Autopilot panel that was on the Carenado.


Notable that the 337 is a unique aircraft to fly. The in-line engine arrangement gives you almost no asymmetrical thrust, but this also a powerful, but brilliantly handing aircraft that has not only a very stable platform feel in the air, but also on departure and approach procedures, you can see why the US Army bought loads of O-2 Skymasters for observation patrols.


So it's a Thranda and that is a sale done right there. At a below US$40.00 price it is also exceptional value for what you get, including free updates for the run of the X-Plane 12 version and all that exceptional quality.  


A total winner in every department...  and positively recommended.



X-Plane Store logo sm.jpg


Yes! the Cessna 337F Skymaster DGS series by Thranda Design is NOW available from the X-Plane.Org Store here: 


Cessna 337F Skymaster DGS series

Price is US$39.95



X-Plane 12 or X-Plane 11

Windows, Mac or Linux
4 GB VRAM Minimum. 8 GB+ VRAM Recommended
Download Size: 1.4 GB
Current version 1.0.3* (February 1st 2023)

*Updates via the Skunkcrafts Updater


Special features:

  •     FULLY configurable 3D instrument panel.
  •     Fully VR Compatible
  •     Interchangeable yoke styles
  •     Over 50 instruments to choose from! (Including Aspen EFD 1000, and support for RealityXP 650 and GTN750)
  •     Move any instrument to any location on the panel, or even between pilot and copilot's panel!
  •     Comes with 4 panel presets, but can easily be expanded by moving instruments around, using a simple and intuitive interface.
  •     Lighting is fully 3D, and dynamically move along with the instruments, as you configure the panel.
  •     Ability to assign a lighting index to individual instruments, to allow different lighting knobs to be assigned on a per-instrument basis.
  •     Save your own presets, and even share them with the community!
  •     Almost every instrument can be popped up or popped out as a 2D floating window! They can be placed on other monitors as well.
  •     Instruments can be moved in 3D directly, on a 2D pop-up preview window, or by numerical entry for precise placement.
  •     GNS430 and 530 can be swapped out, but a restart of the plane is required, as 430s and 530s are mutually exclusive in terms of compatibility in X-Plane
  •     Dynamic livery editor (like in the Kodiak, the Beaver, the Wilga, the Caravan, the C206, and the Pilatus PC-6)
  •     Full PBR control! Create stunning metallic liveries, or matte, sand-blasted look in mere seconds!
  •     Additional control over dirt/scratches, adjustable in real-time to dial in the exact desired amount of wear and tear.  
  •     Create "virtual" liveries, based on two basic common design layouts (Modern and Classic), and assign any colour to any available paint segment.
  •     Quickly create preview of livery in real-time, using intuitive controls.  Previews include visualization of metallic materials and dirt overlays.
  •     Apply selected livery in real-time, right in the sim, without the need to even touch a 3rd party image editor!
  •     Option to change the tail number in real-time, or disable it altogether. (Enter a "space" instead of a callsign number to create a blank tail number.)
  •     Easily and quickly create dozens of paint schemes in-sim!
  •     Also includes 9 traditionally painted liveries, all visible in a convenient pre-selection preview window.
  •     Ability to swap pilot/co-pilot figures
  •     Uses SkunkCrafts Updater.  Option to participate in Beta program, via checkbox in SkunkCrafts Updater.
  •     Excellent hi-res PBR realistic materials, featuring true-to-life plate deformation and to-the-rivet precision.
  •     Fully modelled Continental IO-320-F front engine.
  •     Windshield ice and rain effects
  •     Individual functional circuit breakers.

Feature-rich elegant fly-out menu with the following features:

  •     Electric tug, with in-panel controls to move forward/backward at the desired speed, and steer proportionally
  •     Control over chocks, individual tie-downs, covers, internal lights, external lights, etc.
  •     Option to enable/disable Cargo Pod, with realistically simulated weight, momentum, rotational inertia, and drag characteristics.
  •     Option to start up running (all systems ready), or cold-and-dark, for realistic startup procedures, directly from this fly-out menu.
  •     Control landing lights, strobes, beacon, and nav lights via fly-out menu
  •     Detailed weight and balance manager with visual chart, individual passenger seat weight control, Lbs/KG unit toggle, CG control, external tank control, and the option to save and load configuration.
  •     Show or hide individual seats, to create a hybrid passenger/cargo version.
  •     When seats are hidden, cargo fills the space when weight is added via the fly-out menu.
  •     Multiple camera snap points, above and beyond what's available by default in X-Plane, so you can perform your walk around checks.
  •     Adjust your camera's Field of View without having to go to an X-plane menu, allowing for real-time adjustments.
  •     Audio mixer: individually control audio channels in real-time, so you can adjust volumes while hearing them play.
  •     Slew control: move your plane around the world, temporarily bypassing flight physics.  Includes ground mode and air mode.
  •     Dynamic panel control page, with a separate view for the entire panel layout preview, or a per-instrument view, allowing for fine-tuning of instrument position, as well as copy-paste function to quickly replace instruments.
  •     Option to swap pilot and co-pilot
  •     Option to select different yoke styles
  •     DynaFeel panel: Dial in precisely how you wish for the controls to react as a function of speed.
  •     Optional de-ice system

Flight dynamics and systems:

  •     Detailed and accurate flight dynamics and weight and balance with the help of multiple real-world active Stationair pilots.  This not only gives this aircraft the proper "feel", but also accurate takeoff, climb, cruise, and landing performance.
  •     The C337 is a well-behaved twin airplane, where the engines are in line, with props spinning in opposite directions, cancelling out torque on the airframe
  •     A single engine failure doesn't radically affect flight behaviour, as the engines are in line, and don't produce a net yaw force on the plane, as other twins do.
  •     Tie-downs and chocks actually keep the plane from moving, even in high winds.
  •     DynaFeel: controls that simulate how strongly the control surfaces are affected by oncoming air, and how much strength would be needed to overcome these forces.  

Advanced FMOD-based sound system:

  •     High fidelity, multi-track sounds with smooth, finely tuned transitions (actually having calculated the precise beat frequency for each section, to minimize "muddy" transition sounds), and amazing atmospheric effects.
  •     Individual volume control over different aspects of the sound experience, adjustable in real-time (while listening to the sounds)
  •     Individual sounds for front and back engine, with different sonic characteristics, as a result of their placement.
  •     Different sounds for front of plane than for back of plane
  •     Panning around the plane in exterior view yields awesome 3D audio effects, including "blade slapping" sound when view is perpendicular to prop
  •     Far away sounds include aerodynamic interaction effects between front and rear prop.  At a distance, you hear overtones caused by turbulent air feeding into the rear prop.
  •     Individual buttons and switches in the cockpit each have their own unique sound.
  •     Engine has typical cool-down ticking sound, based on engine temperature.
  •     Sounds actually give you clues as to what's happening under the hood.  
  •     Outside wind intensity is affected by slip and AoA. (The more the surface area of the fuselage is hit by oncoming wind, the louder the sounds
  •     Doors and windows opening, let outside sounds in


Installation and documents:  download for the Thranda_C337F. is 1.34Gb and the aircraft is deposited in the "General Aviation" X-Plane folder.


Full Installation is 1.71Gb


Documents supplied are:

  • C337F Manual.pdf
  • C337F Performance Charts
  • Changelog
  • Thranda Graphics Settings XP11
  • Thranda Joystick Settings
  • X-Plane G430 Manual
  • X-Plane G530 Manual


There is a huge amount of Documentation provided here, not only for the Thranda C337F, but including performance charts, reference guides, but also X-Plane/hardware settings and custom and default avionics.


All updates are via built-in Skunkcrafts Updater


Support forum for the C337 Skymaster by Thranda



Review System Specifications

Windows  - 12th Gen IS1700 Core i7 12700K 12 Core 3.60 GHz CPU - 64bit -32 Gb single 1067 Mhz DDR4 2133PNY GeForce RTX 3080 10GB XLR8 - Samsung 970 EVO+ 2TB SSD

Software:   - Windows 11 Pro - X-Plane 12.01r3 (This is a beta review).

Plugins: Traffic Global - JustFlight-Traffic (X-Plane.OrgStore) US$52.99 : Global SFD plugin US$30.00 : RK Apps XPRealistic v2 - US$34.99



Review by Stephen Dutton
2nd February 2023
Copyright©2023: X-Plane Reviews


(Disclaimer. All images and text in this review are the work and property of X-PlaneReviews, no sharing or copy of the content is allowed without consent from the author as per copyright conditions.



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