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The PA-31 Cheyenne series began when Piper saw the need for a pressurised version of the Navajo, way back in the mid nineteen sixties. It was clear even then that the Navajo was going to be phenomenally successful and that demand for a turboprop version was building. The Cheyenne took Piper into uncharted waters and was a much more sophisticated aircraft than anything the company had tackled before, so that although the prototype was rolled out in fall 1969, it took another five years to get the bugs out. Piper had to redesign the flight control systems to handle the increased loads resulting from the higher airspeeds the Cheyenne cruised at and worse still, the Lock Haven plant was flooded in '72, so that the first delivery didn't take place until 1974. Confusingly, the original production hull became known as the Cheyenne II, because it was fitted with more powerful (620 shp) engines than the Cheyenne I, which was introduced four years later, powered by 500 shp PT6As. The 1978 Cheyenne I cut quite a lot of cost out of the equation, because the reduction in power meant that it didn't require the Stability Augmentation System Piper had to build into the II before it could be certified. The Cheyenne I was upgraded to the IA in 1983, most of the improvements centering around the engine airflow and electrics.
The Cheyenne II hull subsequently appeared in a stretched version, which - like the I - doesn't have the SAS and is known as the IIXL, appearing in in 1981. Sales hiccupped because the Cheyenne II garnered quite a reputation following a couple of takeoff accidents which were widely blamed on longitudinal stability and pitch problems, but these faded away with the introduction of the IIA. None of this really harmed the program and when PA-31 production ended in the mid-eighties, over 800 hulls had been sold, so it was a popular airplane by anyone's reckoning.
For what it is worth, in the mid seventies, Piper began development of a T-tailed version aimed directly at the lucrative market which was being corned by Beech's big turboprop - the King Air. This was the PA-42 Cheyenne III announced in fall 1977 and granted FAA certification in 1980, with deliveries beginning in the same year, the ultimate model of which is driven by a pair of 1000 hp Garrett TPE331s and is a hot ship indeed - although the PA-42 isn't included in this addon, regular readers will remember FSD did a version a few years back.
The Aerosoft Cheyenne X has been developed by Digital Aviation and includes all four PA-31 variants, with three liveries of each and the addon is available boxed from the Pilot Shop. The developers have a good track record and should be fairly well known now, their Dornier 27 for FSX being one of the best addons I have ever reviewed, another product of theirs that is worthy of a look being the Diamond Katana, which is also available for FSX. Both these addons are first rate and I notice that Digital Aviation have both a CRJ-100 in the works and a Fokker 70/100, both of which should be exciting releases.
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Installation of the Cheyenne is straightforward and when it was done, I found a new program group on the Start menu under the Aerosoft banner, which contained links to a wealth of pdf documentation, including: manuals in English, French, Spanish and German; a separate manual for the procedures; a set of performance tables, which is required reading if you want to fly the PA-31 like the real thing; a tutorial in English and German; and a weather radar manual, again in English and German (where not stated, the documents are available only in English). All the documentation is extensive and well presented, the aircraft operation manual (AOM) alone running to 180 pages, although curiously, the links to the German and English language docs were the wrong way around in the version of the addon I reviewed.
The most important document is the AOM, which goes into great depth about how the panel works; the sections on the radios, engine management and autopilot/flight director being especially worth reading. There are many pages of cruise power tables in there, which you might be tempted to skip, but they are vital if you want to fly the PA-31 like the real thing, chiefly because turboprops are literally flown 'by the book', the idea being that you select your cruise power by flight level, set the engines up according to the tables and then don't touch the levers again until it is time for descent. Dozens of pages of performance charts follow the power tables, which can be used to calculate the performance of the plane under just about any circumstance, but they aren't particularly valuable unless you are faced with getting a real Cheyenne out of a short, hot, high field and climbing to FL290 without breaking either the airplane or yourself. The meat of the text begins again at page 69, from which point you are treated to an in-depth discussion about the features of the sim, continuing until you reach the final quarter of the manual, which walks you pretty much all the way through a flight, this section being more or less duplicated in the tutorial.
Try as I might, I could not find a set of minimum system requirements for the addon, beyond the obvious need to have FSX - I did the review on a 2.66 Ghz Core2Duo with 4 GB of RAM, a 768 Mb GeForce 8800GTX, Windows Vista SP1 and FSX SP2. Frame rates for the Cheyenne appeared to be 33% slower than the default Lear, so I wouldn't suggest running the addon on less than a 3.0 Ghz processor with a couple of gigs of RAM - but then again, I wouldn't suggest running FSX on anything less than that anyway. The Captain Sim C-130 returns almost identical frame rates, which suggests that there is room for improvement where the Cheyenne is concerned and - out of interest - this review is the first time I have been able to use the FSX SP2 DirectX 10 preview without causing all kinds of texture mayhem, which may or may not be down to the fact that I have Vista SP1 installed now. The good news is this combination improved the frame rates by about 20-25% when I ran the PA-31.
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There has been an increasing trend over the years for top end addons to be supplied with configuration manager applets of one kind or another and the Cheyenne is no exception, the app in this case being accessed with the plane loaded by hitting Shift-7. The config manager lets you fill the seats with men, women and children, but you can't put any kids in the pilots' positions - someone at Digital Aviation has clearly been on a Health and Safety course. You can also this useful app to load the panel cold and dark; to toggle the yokes in and out of view; to show an analog VSI should you get bored of the digital one's TCAS; to display the radar/HSI as 2D object in the virtual cockpit (VC) in order to save some frames; to simulate wearing a noise reduction headset; and to adjust the sounds levels in the cockpit independently. While I am on the subject, the sound set is a good one. Makes noises... that kind of thing. Okay - it sounds very like a pair of PT6As.
Taking a look at the plane itself, the developers strongly suggest loading one of the default planes at a default airport first and I heartily agree with the idea, as doing anything else risks FSX becoming tired and emotional. One thing that I did note is that after a few swaps back on forth between the PA-31 and the Lear to check frame rates, the PA-31 torque stopped responding to throttle movement, but few readers are likely to subject the addon to a simular insult, which appears to be due to the Cheyenne coding on throttle limits. The visual model is very good - much better than the FSD PA-42, which is ageing now and never was exactly perfect. The detailing is fine and you get plenty of animations, including opening doors; folding desks in the virtual cabin; and chocks and a tow bar appear if the parking brake is set, the prop controls are at stop and the engines are off; beyond that, all the usual animations are present. There are three liveries for each version of the Cheyenne, none of which are duplicated between the versions and which cover American, French, British, German, Portugese, Swiss and Dutch planes among others. One curiousity is that once you have selected one of the PA-31 models in the process of creating a new flight, the rotating model appears attached to an external power supply unit, but with its wheels retracted, which is trivial in some senses, but leaves an impression that the quality control hasn't been all it might have been in what is, after all, a reasonably expensive sim and needs fixing.
From the left hand seat, the 2D panel has normal, VFR, landing and IFR views, the latter taking me back to the early DreamFleet days when no addon was complete without a view that put the pilot's eyepoint somewhere where the real guy's knees would have been. Once you get the hang of the click spots, you can race around the views, failing which, you can always resort to using the W key. Apart from the four pilot views, you can swap to the right hand seat and other pop-ups include a zoomable ADI/HSI, the yokes, fuel crossfeed, overhead, pedestal, the radios and Nav 2. The 2D panels are all photoreal and based on high resolution graphics, so you can run 'em on as large a monitor as you like - all the gauges look very believable and the reflections are nicely done. Coming from the era it does, the PA-31 has a largely analog panel, but is fully equipped for airways flying, so you get a radar altimeter, ADI and RMI in addition to a comprehensive radio fit, a Trimble GPS and weather radar. The ignition and lighting lives up on the roof, hence the need for the overhead pop-up. The left hand ADI simulates a KCI 310 and is a real box of tricks that does RNAV if you select the GPS using the Nav/GPS switch under the glareshield in front of the left hand seat; while the HSI appears to have all the features you would expect of the unit it simulates, which is a KPI 553A, a most useful feature of the unit being that when you are less than a thousand feet above ground level, the groundspeed/time readout changes to radio altitude. Another gauge worthy of a mention is the combined VSI/TCAS, which is switchable between 6 and 12 mile range and on the Cheyenne II, you get the SAS, which tells you when the wing is considering quitting doing its stuff. As far as I can tell, just about every system on the Cheyenne is simulated, including virtual pressurization. A minor problem with the 2D panel is that if you hit the A and W keys too often, sooner or later the outside view loads without stretching the full depth of the windshield and you end up with a small black triangle at the edge of the glareshield - I haven't seen this in a long while, though it used to be common in FS98 addons for some reason.
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The plane is fitted with a Bendix-King KFC250 three axis combined autopilot/flight director unit, which is about as sophisticated a box as you are likely to find on a GA plane. Three axis means that the KFC250 uses pitch to control airspeed when in IAS mode, so when it is used in combination with the Altitude Selector, you can set up a climb to a flight level at a given speed and have the plane automatically level off when it gets there. Although there isn't an autothrottle in the PA-31, the unit has a rather neat Speed Profile mode, which allows you to dial in an airspeed, which the FD adjusts for altitude and you can also set up a climb using the pitch mode.
The stack simulates the Bendix-King Silver Crown Plus set and comprises a KMA 28 audio panel, paired KY 196A and KY 53 com and nav radios, two KR 87 ADFs and even a pair of KT 76C transponders. As mentioned above, DME from either of the Nav radios can be displayed on the pilot's HSI and it is possible to 'hold' a DME from one of the radios, while tuning the same radio to a different VOR, which is very useful for airways navigation. Just about all the modes the real radios are capable of seem to have been simulated, otherwise there isn't much to say about the stack, beyond the fact that the transponders are Squawkbox 3 compliant.
The VC is OK and duplicates all of the functions of the 2D panel so that I could use it to fly the plane most of the time, although it is slow to skin. In common with many VCs that started their life in FS2004 addons, the VC looks a little lacklustre and could be sharper, but that being said, it is way beyond anything the default planes have to offer. The one time that the VC doesn't provide the same level of functionality as its 2D counterpart is when you are programming the GPS, which involves fiddling around with the buttons and knobs - just like the real unit - unless you cheat and drop out into 2D mode to take advantage of scroll-lock enabled direct keyboard entry. In practice, since you don't need to do much with the GPS once you have loaded a flight plan, you are only likely to need to use 2D mode during pre-flight.
In some respects, the jewel in the panel is the Trimble 2000 Approach Plus GPS, which simulates all the major functions of this early unit, including flight plan storage, procedures, user-defined waypoints and holds. You might wonder why Digital Aviation didn't stick in one of the more modern mapping units, but the Trimble is exactly the kind of thing a PA-31 would have been fitted with in its heyday and many Cheyennes are still being driven around the airways by them. This is a complex unit which has many pages devoted to it in the AOM and it can be used in conjunction with the real Trimble manual, but you will be delighted to hear that the developers have 'enhanced it' so that pressing the AUX key will let you load FS flight plans and that you can also type directly into the unit by pressing the Scroll Lock key, but only while you are in the default 2D panel view. To get the plane to follow a GPS flight plan, you have to set the VOR/GPS switch to GPS, activate the NAV mode on the autopilot and ensure that you don't have the Nav1 radio tuned to an ILS. Apart from that, once you get the relationship between the FD, the autopilot, the Nav/GPS switch and the Altitude Selector straight in your head, the sim is a doddle to fly and I flew using VOR nav, the GPS and did several localizer intercepts without any problems.
The flight model is good, barring a tendency to skid at low
airspeeds which is shared with many FS flight models and can
occasionally result in hard to correct sideways drift on approach;
the other issue being that keeping the nose straight with one engine
shut down can be done with hardly any use of the rudder at all, which
simply can't be right. On the plus side, Digital Aviation have
captured the slow spool up time of the PT6As very well, which is a
positive encouragement to fly the PA-31 correctly - this sim will
bite you if you don't plan your approaches, intercept the localiser
at a reasonable distance out and stablize the plane before you
descend. If ever there was a flight model to teach you how to fly a
glideslope using pitch instead of throttle, this is it, because if
you chop the power when you find you are too high on short final, the
engines won't respond in time to haul your ass out of trouble if you
overcorrect and your approach turns into an undershoot. This is where
all those tables come in handy and before you fly so much as a
circuit in the PA-31 and I would strongly advise writing down all the
relevant speeds, flap, gear and power settings, because knowing these
is the key to arriving in one piece. One snag, however, is that even
after repeated recalibration of my CH Products yoke, the throttle
lever did nothing for half the range, effectively making the control
far too sensitive, which caused more than a few problems,
particularly when I was flying approaches and needed to make fine
adjustments to the power settings.
Verdict? The Cheyenne was originally developed for FS2004 and while it works well in FSX, it doesn't feel totally comfortable in the new version of the sim; nor does it have the immense presence of the Digital Aviation's Dornier 27 - which I'll admit is up there is in a class of its own. The port over to FSX could have done with a little more attention having been paid to it and package could definitely do with a bit of a tidy up. Nonetheless, PA-31 is a very good addon and it is one of the best twins available for FSX.
Andrew Herd
andy@flightsim.com
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