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Turboprop Singles: No One-Size Solution
You can have speed, or brawn or both, and often for greater economy than those little jets.
By Rick Durden
Those who make money in conjunction with airplanes do so by finding a niche demand that is unfilled and proceed to fill it effectively before any other supplier figures out it exists. Manage such a feat and you can chortle all the way to the bank.
Four manufacturers have been coining money by filling a niche that the majority of the aviation market seems to have ignored: The market for owner-flown, single-engine turboprops.
Birds of a Feather
EADS-Socata, Piper, Pilatus and Cessna have been building single-engine turboprops for several years now, and their assembly lines appear at or near capacity as there are healthy waiting lists for new airplanes. Pilatus and Cessna originally built their airplanes for cargo, bush and military operators but found, to their delight, that owner-pilots got in line to buy.
On the surface, these four airplanes are quite different. Despite all being powered by a version of the PT6, cruise speeds and cabin sizes differ noticeably, as does the ability to carry a load. Yet the series seems to attract a certain kind of buyer: one who wants the reliability of a turbine, doesn’t want the hassle and expense of a type rating and more than one engine; who desires an airplane that can go in any weather the pilot is personally capable of handling, and will either go fast or carry a big load. (We recognize that there are a few other single-engine turboprops, such as the new Quest Kodiak and the PC-6 Turbo Porter, but we are limiting our comparison to airplanes currently built in bulk for the owner-flown market.)
Two distinct methods of grouping these airplanes emerge: either by price, with a well-equipped Cessna 208B Grand Caravan or Piper Meridian at roughly the $2 million mark and the TBM 850 and Pilatus PC-12 hovering near $3 million; or by size, the personal traveling machines being the Meridian and TBM 850 with the PC-12 and Grand Caravan the swallow-it-all loadhaulers.
There are no dogs here. All are without handling vices. Fit and finish is generally excellent, as one would expect when plopping down a few million. And all have the useful ability to fit in no matter what the ATC environment; mixing at whatever speed is needed in the traffic pattern at small airports or staying with the jets at 160 knots until short final and then slowing rapidly to 85 knots over the fence.
Each of the airplanes is approved for flight into known icing and all now have glass cockpits with varying degrees of integration, the PC-12 being the most advanced.
All four airplanes offer first-class amenities for passengers and crew. The TBM has a huge passenger/cargo door and an optional pilot door.
All have sophisticated systems with duplication and backup for about everything—save powerplants. Even if the PT6 should shuffle off its mortal coil, the prop-feathered glide ratio for each is far better than a piston pounder.
All need about the same space to clear an obstacle on takeoff, on the order of 2600 feet, or to land. We would feel comfortable basing any of the single-engine turboprops at a 3000- to 3500-foot strip at sea level, provided there were minimal obstacles. That is shorter than the accelerate-stop or accelerate-go distances for virtually all piston twins.
Perhaps because all of the manufacturers have been around a long time (EADS-Socata traces its linage to 1911), the airplanes are all notably conservative in design; all are metal, with limited or no use of composites in the airframe. Given the sophistication of turbine power, we would have expected to see at least one of the models provide a little more impact protection for the pilots by going to side sticks rather than yokes (although such a design would be a challenge for the 208B and TBM with the pilot-side doors).
Size, Power and Weight
Once past the common features, the differences are striking. The PC-12 is the largest of the airplanes, with an overall length of 47 feet 3 inches and a wingspan of 53 feet 4 inches, and has a cabin larger than a King Air 200. At 1200 SHP
Ground-handling tools store neatly up by the nose.
available for takeoff and 1000 continuous, it also has the most muscle, which it needs to haul a hefty 4021-pound useful load, or 1317 pounds with full fuel aboard, and take it high and fast.
Next in descending size comes the Grand Caravan, with an almost identical wingspan at 53 feet 1 inch, but a notably shorter length at 38 feet 9 inches. Despite its bulk, the 208B has the second smallest engine, rated at 675 SHP, which still allows it to carry a useful load of from 3188 to 3785 pounds, depending on how fancy the interior is. Call that 964 to 1564 pounds with full fuel. The 208B can outlift the PC-12 with full fuel, but only if the 208B has one of the more generic seating packages (which generally is not the case as the owner flown airplanes are usually delivered with optional, heavier interiors).
The TBM 850 is larger than one expects at 34 feet 11 inches long with a wingspan of 41 feet 7 inches. TBM engineers discovered that the cruel physics of the weight of jet fuel and the higher specific fuel consumption of turbine engines mean that it is not possible to hang a turboprop on an airplane that fits in a tee hangar, and still carry passengers if loaded with enough fuel to do more than a trip around the pattern. The TBM 850 has 700 SHP available for takeoff, increasing to 850 once the flaps are retracted. Even so, the TBM 850 gets aloft with a useful load of 2750 pounds, or 806 with full fuel.
While all offer first-class avionics, the PC-12’s Primus Apex system stands alone in capability.
While Piper’s advertising extols the power of the Meridian, it is the baby of the bunch at 500 SHP, yet it is on the smallest airframe: 29 feet 6 inches long with a 43 feet 13 inch span, so it cooks along nicely with a 260-knot cruise. The Meridian runs into the economies of scale that so bedevil designers; while its useful load is a respectable 1475 pounds, once full fuel is added, only 499 pounds may be carried in the cabin. The weight versus fuel conundrum of smaller airframes partially illustrates why Cessna and Beech experimented with a turboprop P210 and Bonanza, respectively, but didn’t put them into production.
Piper Meridian
The size and load carrying numbers, along with price, make the decision on which airplane to purchase fairly easy for those who have a specific mission and budget in mind. For the owner-pilot who routinely flies alone or with just one other person, the Meridian is ideal. It will zip along at a top cruise speed of 260 knots burning about 260 PPH and, following an unrestricted climb to FL300, Piper advertises that it can go 1000 nm VFR; or about 850 nm IFR with reserves. Fuel burn is critical; any time spent below the flight levels seriously eats into the range and endurance, the downside of a turbine in a small airframe.
The Meridian requires the highest altitude of the group, FL300, to get its published range. The pressurization system on the Meridian has a maximum differential of 5.5 PSI, putting the cabin at about 10,200 feet when operating at FL300, its maximum range and altitude.
A subtle advantage the Meridian sports is that it does not require an inertial separator, which protects the expensive engine from damage when flying in icing conditions. The engine does not need the intake ram effect others do to make power, so Piper could use non-icing NACA ducts on the nose, thus protecting an owner-pilot from making what can be an expensive oversight.
TBM (above), Cessna (below top) and Pilatus (below bottom) offer ample head and leg room in back. The Caravan and PC-12 have cabins big enough for multiple seating options, cabinets and a basic toilet. Piper’s cabin is lower, with the seats closer to the floor, but still quite comfortable for two adults.
The few complaints we have about the Meridian are the uncomfortably small cockpit and the switches located on the overhead above the windshield. Despite some work on seating, pilots taller than about six feet will not find it an amenable place to spend time. The overhead switches block the view forward during a descent, and are difficult to read (especially for the bifocal set, who generally are the ones who can afford a Meridian). This panel and the tight cockpit, present, in our opinion, a risk of head injury in even a fairly low-speed impact, such as a runway overrun.
We are curious if owners routinely remove one or two of the cabin seats to allow a little more weight to be carried and provide stretch-out space as putting five or six adults in the airplane limits fuel to 250-300 pounds—less than an hour’s worth.
TBM 850
Should another million dollars not be an obstacle, the pilot looking for the perfect, personal hotrod can step up to the TBM 850. The TBM’s 850 SHP on a clean, modest-sized airframe means speed. We observed 315 knots at max cruise in our evaluation flight, just under the 320 advertised by Socata. However, Socata publishes the speed for an airplane without a radome on the wing—unlikely in the real world. Fuel burn at that speed is 396 PPH, with its 1887 pounds of fuel allowing a VFR range of some 1365 nm and an NBAA IFR range of 1000 nm with a pilot plus three passengers. Best altitude for the airplane is FL 260, a height that should generally be available and below the jet traffic.
The TBM 850 does have a zero fuel weight, but even with the cabin loaded to the maximum zero fuel weight of 6032 pounds and then fueled to gross weight, the VFR range is over 1000 nm. The cabin is large enough to carry the pilot plus five comfortably (pilot plus 3 with full fuel); in fact, the seat rails are continuous through the length of the cabin, creating a wide selection of seat locations. The
larger airframe allows for baggage storage behind the seats, as well as outside of the pressure vessel.
Max differential pressure is 6.2 PSI, giving a 9300-foot cabin at the FL310 max operating altitude.
We would like to have seen Socata keep the fuel lines out of the pressure vessel on the TBM, as Piper did on the Meridian, although we applaud that the integral fuel cells in the wings are protected by the spars, a strong point on the crashworthiness scale, as is Socata’s announcement that it plans to offer seat belt air bags. We also like the "crash switch" that allows the pilot to shut down the entire electrical system with one finger in an emergency to reduce the chance of post-crash fire.
Cessna Caravan
For the prospective buyer with a Meridian budget, but the need to haul a lot of people and/or stuff, the Cessna 208B Grand Caravan may be the right choice. The unpressurized, fixed-gear 208B is not fast. It was designed as a work horse, so a 160-knot max cruise (with cargo pod, as most are so equipped) is the result. For that speed and a burn of 330 to 340 PPH, plan on an altitude in the low teens and, possibly, oxygen for you and your guests.
If you want to go a long way, pass out the masks as the 2240 pounds of fuel will give you 1000-nm, VFR range at FL200 (max operating is FL250). NBAA IFR range is about 850 nm, but depending on the weight of the interior furnishings, you can take eight of your friends along with you.
The cabin is extremely wide, allowing 2+1 seating on either side of an aisle, or 1+1 in seriously large seats on either side of the aisle. You can add a potty at the aft end in the top of the line "Oasis" interior (which adds a whopping 600 pounds to the empty weight of the airplane).
The 208B Grand Caravan is a basic, working airplane, dressed up for the owner-pilot crowd. The Oasis interior turns it into a true luxury transport that allows it to park on the swankiest ramp without apology. We like the crashworthiness of the design, with such things as five-point harnesses for the front seats (the best of the bunch), the manner in which the fuel cells are protected between the spars and well outboard of the cabin, as well as the design of the main landing gear to
TBM and Pilatus have extensive support in the U.S. despite being built overseas. (PC-12s arrive “green” to be finished in the U.S.) This means parts are readily available, although the weak dollar may not make getting them any more pleasant.
snap off without deforming the cabin floor when subjected to heavy aft loading that might otherwise flip the airplane. Four cabin doors doesn’t hurt when it comes time to deplane hurriedly.
Pilatus PC-12
Adding a million to the budget for the Grand Caravan shopper means stepping up to pressurization and 100 more knots for cruise on about the same fuel burn. The Pilatus PC-12 with its BMW-styled interior, cargo door that is, perhaps intentionally, an inch taller and wider than that of the Grand Caravan, has a max cruise speed just a bit faster than the Meridian, 270 to 280 knots with the uprated -67P engine due out in early 2008. With a fuel burn of 330 PPH, best altitude is FL240. The 2704 pounds of usable fuel gives the airplane a stunning 1500 nm NBAA IFR range with a pilot plus five aboard. If one desires, it can stay aloft some eight hours at max economy power settings. Yes, it has a potty, directly opposite the airstair door. Max differential for the pressurization system is 5.75 PSI, giving a 10,000-foot cabin at FL300, the maximum certificated altitude for the airplane.
The Honeywell Primus Apex glass panel system in the PC-12 is about as fully integrated as it gets on any airplane, even handling pressurization and climate control and presenting the flight plan graphically, and allowing it to be amended by moving portions of it with a cursor. It is the only airplane in the group to have a single power lever; all others require the pilot to set propeller rpm. Where the Cessna 208B was designed for bush operations by making the airplane systems extremely simple, the PC-12 philosophy was to install power steering to handle the bad roads. The landing gear retracts, but is of trailing beam design and rather dramatically overbuilt, which along with low pressure tires gives excellent rough field capability. There is an optional battery heater for cold weather operations (on the Caravan the battery can be removed in seconds and taken indoors). The PC-12 cargo door opens and shuts with a motor drive as opposed to the manual operation of the 208B (there is a manual reversion). The PC-12 is the luxury yacht of the group.
Outstanding support
All four manufacturers are fully aware that service in the field is of the highest priority and each has the resources to provide it. Feedback we received from owners was uniformly positive. For simple dispatch reliability, the Cessna 208 series is unmatched, partly because there are far fewer things to break on the fixed gear, unpressurized airframe.
Warranties for new airplanes varied widely from Cessna’s minimalist one year to the amazing seven years on the airframe and five on the engine offered by Socata and Pilatus. There are also specific hour limits, although Socata pays for the first few annuals and scheduled inspections. That may explain some of the price of the TBM 850 and PC-12, but it means that its owners are only going to be paying for consumables for quite some time after purchase.
Away from the tumult of the VLJ fray, these four companies have done an excellent job of creating aircraft that fit the specific requirements for reliability, speed, ability to carry a load and deal with weather while keeping operating costs notably less than a small jet or turboprop twin.
The market has spoken; four astute manufacturers listened well and are now collecting their rewards.
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Good judgment comes from experience, and a lot of that comes from bad judgment-Will Rogers
Last edited on 12 Nov 2009, 21:58, edited 1 time in total.
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