How do you one-up the world’s best-selling helicopter, the Robinson R44? Simple. You put a turbine in it. But wait! … It wasn’t that easy.
Talk of a “Robinson turbine” began swirling around the helicopter community clear back in 2001. But if you asked company CEO and founder Frank Robinson back then if the company was indeed working on such an animal, he would smile and get very elusive. Truth is, Robinson had been thinking about a kerosene-powered helicopter for some time, but he wasn’t happy with the engine choices available to power the design. Everything he looked at, including the Rolls-Royce 250-C20B, lightest of the offerings, was too heavy — and too expensive. Over the years, while the turbine project moved from front burner to back shelf to front burner, Robinson investigated many power-plant options, including diesels. But the diesel options were all too heavy and didn’t offer enough advantages over the small turbines available.
So Robinson went to Rolls-Royce, asking it to design a “lighter, simpler, less expensive” turbine to power a slightly scaled-up R44. The result was the RR300, a new design with deep roots in the Allison/Rolls-Royce Model 250-C20 series turbine that has powered stalwarts such as Bell’s JetRanger, Hughes/McDonnell-Douglas’ MD-500 and others for decades. This new engine, certified by Rolls-Royce in early 2008, made possible a remarkable new helicopter that should be certified by the time you read this. It’s called the Robinson R66 Turbine.
The new engine is indeed lighter — it weighs 201 pounds installed, less than half the weight of the IO-540 piston engine on the R44 Raven II sibling. The engine is also simpler, with a single-stage centrifugal compressor instead of the C20’s more complex six-stage axial and one single-stage centrifugal compressor. It’s rated at 300 shp maximum, 270 shp for five minutes and 224 shp continuous. Initially, the turbine will have a TBO of 2,000 hours — 200 hours less than the airframe’s required overhaul time – but Rolls is determined to raise that as it gets field experience with the new design.
Engine bleed air is utilized for engine anti-ice and cabin heat, which, as in all turbines, robs power when it’s selected. The performance charts reflect this degradation in performance, advising you to add 10 degrees C to the outside temperature numbers when engine anti-ice is on, or 20 degrees C if cabin heat is on. But with bleed air off, the ability of this ship to hover out of ground effect is impressive: more than 12,000 feet at maximum gross weight.
That “lighter, simpler, less expensive” design philosophy is obviously a steadfast core belief at Robinson helicopter. Kurt Robinson, who took over the reins as CEO and president of the company this summer when his 80-year-old father retired, told me proudly, “We build Fords and Chevys here.” The message was that the company’s light, simple products perform well and inexpensively without flash and complication. This new turbine helicopter comes to market at a price point that will ensure its success: $790,000. To put that into perspective, when Bell abandoned its entry-level 206B-3 JetRanger III production in 2008, it was priced at around $1.3 million, reasonably equipped. That leaves only two other competitors for the R66: The Sikorsky S-333 at about $900,000, average equipped, and the Enstrom 480B, which sells for about $1.05 million to $1.1 million.
Simple Is as Simple Does
Preflighting the new design is simple and straightforward. The usual scrutiny of blades, skids, cowlings and general airworthiness items is unremarkable. At first glance, the only things to differentiate the R66 from the R44 are the turbine engine’s intakes at the base of the main rotor-mast fairing and the cooling screens located aft, above the engine compartment. But the main rotor mast is 8 inches higher, and the new machine is 7½ inches wider than an R44.
Another difference is the type of main rotor blades. In field use, Robinson found that its stainless-steel main rotor blades were too easily damaged, so it has gone back to aluminum blades for the entire fleet from R22 to the R66 Turbine; a set of aluminum main rotor blades is about a pound lighter than the stainless, thus payload is improved slightly, and autorotation characteristics are unchanged. The main rotor disc area of the R66 is the same as in an R44, though the chord is 1½ inches wider. The tail rotor blades also have a slightly wider chord and are 2 inches longer than an R44’s blades.
There is an access door on the left side of the aircraft that offers a great view of the lower mast area. When opened, a microswitch automatically turns on small LED lights that illuminate the hydraulic reservoir, main rotor gearbox and other essential inner workings that should be checked before flight. Nice touch. On the right side of the aircraft, a large access door opens to reveal a large portion of the engine compartment. There is also an access door on the left side of the helicopter’s upper deck that covers the fuel filler cap. Contact switches on each of these doors and the baggage door annunciate to warn the pilot if any are left open.
As in most new aircraft these days, all aircraft lights, including position, beacon strobe and instrument panel, are LED types, which draw very little power and are lighter and longer lasting. The nose-mounted landing lights are HID, or high intensity discharge. This should remove any objection to running all the lights, including landing lights, all the time for extra visibility.
The new baggage area is accessed through a large, top-hinged door, located slightly below and aft of the right rear cabin door, and opens wide to a generous baggage area. Though I was assured golf clubs would fit (I didn’t bring mine for this evaluation), they must be removed from the bag. There’s a 300-pound limit on the compartment, and since it is just aft of the rear seats, aft CG shouldn’t be a big issue.
The cabin doors are the same light, simple doors found on all other Robinson products, with small, stay-open gas struts for ease of entry and exit. Inside, there is seating for five, although the “fifth seat” is a rather narrow rear middle seat, slightly elevated and forward of the two outside seats. This allows three-abreast seating without having the passengers’ shoulders jammed together, though headroom is a bit tight. I sat in the seat for a few moments, and my head (I’m about 5 feet 10 inches) was right in the headliner. For ride-hopping or short flights, that would be acceptable, but this seat is not for long trips. Kurt Robinson admits that the R66 is “an honest four-place,” saying, “It’s just like in your car; you can go across town with all seats filled, but you might not want to go all the way across the state of Texas that way.”
The seats of this helicopter are deceivingly simple; they appear to be small cushions with a light, flip-up hinge, but the seat structure is certified for 20 G loads. They are also built for a maximum 1,500-pound spinal compression load. This was admittedly one of the hardest things to get right during certification, and Robinson admits it took several attempts to finally show compliance with FAR 27 requirements.
Under-seat storage is also reduced from previous Robinsons. Now, there is a fiberglass housing attached to the aluminum seat bottom that provides additional vertical crush capability in an accident. The new housing also restricts the amount of cargo that can be put in the compartment below the seat. There’s a new placard inside the compartment showing the maximum height to which cargo can be loaded; this is designed to keep operators from overfilling the compartment and reducing the seat’s crashworthiness. But the new baggage area compensates for these new restrictions because it accommodates so much cargo.
Though some wished for a “real cyclic,” that is, one centered between your knees, on this new helicopter, the R66 retains the trademark “teetering” cyclic of all Robinson designs: A single post comes up through the floor between the two front seats, with a horizontal bar and separate handgrips for each pilot; you “teeter” the handgrip in your direction if you are flying, leaving the other handgrip well above normal hand height. Some people love this arrangement; others (mostly those who haven’t flown the design much, or at all) hate it. Once you figure out where to put your wrist while flying (on your right thigh, as on most other helicopters with “conventional” cyclics), you learn that the teetering cyclic does the same thing that any other cyclic does, and you forget the difference. It’s admittedly odd the first few times you fly one, but you soon learn to appreciate the simplicity of the design. It’s lighter and simpler, and it’s a hell of a lot easier to get in and out of the helicopter.
The empty weight of the ship we flew, serial number 3, was 1,304 pounds. That’s roughly 200 pounds lighter than the average R44 Raven II. Gross weight is 2,700 pounds, which is 200 pounds more than the Raven II. That translates to a pretty hefty useful load of just under 1,400 pounds. When was the last time you encountered an aircraft that could pick up its own empty weight — plus almost 100 pounds? With five 170-pound people in the cabin and full fuel, 74.6 gallons, you can still add 47 pounds of baggage. For a light helicopter — or any light aircraft, for that matter — that’s impressive.
The instrument panel will be instantly familiar to any R44 pilot with the exception of a torque gauge and an MGT, or measured gas temperature, gauge. Oddly, the MGT gauge is small and located on the lower console panel next to the oil pressure and temperature gauges instead of up on the instrument panel, next to the torque gauge. Since most of my helicopter flying is at high-density altitudes in Colorado, I would have located the MGT right next to the torque gauge to reflect its importance in high/hot conditions. Perhaps the decision to install it where Robinson did reflects its flying predominantly near sea level around its southern California home, where the first limit reached in most turbine engines is torque, not temperature. It’s a small nit but might be an important consideration for high-density altitude fliers.
Simple Start
Startup is not all that different from an R44’s. There’s a large “enable” switch in place of the magneto switch that simply arms the igniters. There is no electric boost pump (or pumps) to turn on to provide head pressure to the engine-driven pump; this is a completely gravity-fed system. So, it’s master switch, beacon strobe and enable switch on, then press and release the start button, watch the little turbine spin up to 15 percent, push in the cable-operated fuel cutoff control (which looks just like a mixture control from an R44) and monitor the temperature as the fire builds in the combustion chamber. While spooling up, you keep your hand on the fuel cutoff (mixture) control to be ready to stop the fuel flow should the start temperatures get too hot; if that happens, the starter continues to motor the engine to cool the turbine back down. On every one of our four starts, the start temperatures (at sea level, roughly 70 degrees) were very cool, around 750 degrees C, and well below the 927 C limit.
Once started, it’s generator on, radio master on, hydraulics and anti-ice check, and you’re ready to fly.
With Robinson test pilot Doug Tompkins and myself aboard, each weighing about 180 pounds, the R66 picked up slightly aft and left skid low. This took me a few iterations to get used to. But once airborne, the ship felt a lot like an R44 in both hover and hover taxi. The RR300 turbine runs cool at these elevations and temperatures, and it was very difficult to get much of a rise in MGT, even with aggressive tail-rotor inputs.
The helicopter felt very light and responsive and was fun to fly. Tail-rotor authority, as in all Robinsons, was very positive and confidence-inspiring. The R66 is a bit faster than an R44; I easily saw 130 knots indicated at high cruise settings, on about 20 gallons per hour. That’s not much more fuel burn than an R44 Raven II’s. In the real world (one without wind, of course), with full fuel aboard, you could fly 2½ hours, something over 300 miles, and still have nearly an hour’s fuel reserve. Pete Riedl, vice president of engineering at Robinson, told me that during 150 hours of FAA-required testing, with a new-spec engine at max continuous power, the ship averaged just 20.5 gallons per hour.
Hovering autos display plenty of forgiveness due to the high inertia of the rotor system. This was true of the straight-in and 180-degree autos as well. This machine’s excellent auto-rotation characteristics remind me of a JetRanger’s with the exception that, as with any Robinson, you use the collective more actively to manage rotor speed during the autorotation than on many other helicopters.
We flew the R66 to 7,000 feet on one of my flights to sample the performance at high-density altitudes. Traffic from nearby LAX and other local airspace restrictions kept us from climbing higher, but the density altitude on this warm September morning was a smidgen over 9,000 feet. Hovering out of ground effect at this altitude was a nonevent; the helicopter accomplished the task without breaking a sweat, with MGT showing temperatures in the bottom of the yellow band starting at 706 degrees C, where the engine can be run for five minutes continuously. Again, the tail rotor was very positive and competent.
To shoot pictures of the engine for this article, we asked Robinson to remove the engine cowling. I always apologize when I ask for a cowl removal since those requests usually don’t ensure your place on some hapless mechanic’s Christmas card list. But the mechanic smiled, said it was “no problem at all,” grabbed his rechargeable screwdriver, backed 10 screws away in a couple of minutes, and the cowl was gone. Everything on the engine was visible and accessible. You wouldn’t have much better access if the turbine were mounted on an engine stand. That should save operators some bucks on maintenance.
The R66 Turbine is an impressive machine, especially at the under- $800,000 price point. With the company’s “lighter, simpler, less expensive” philosophy, it has created its own market niche — and a product to fill it well. Robinson has a winner on its hands with the R66 Turbine, and I predict it’ll sell a ton of em.
