Wednesday, September 24, 2014

Carbon Envy

I have only flown a handful of taildraggers in my life: the Piper PA16 Clipper, Aeronca Champ, and Bellanca Super Decathlon before I had my tailwheel endorsement, and the Cessna 170B and my club's current 1946 Piper Cub since. I look at Luscombes, Piper Pacers, and Stinson 108s on barnstormers.com all the time, but I have yet to fly any of these. I just haven't put the necessary legwork and gumption into making contacts and scoring rides, I guess. Compare this to "Weasel," otherwise known as Eric Whyte, chairman of the AirVenture Cup race that I recently participated in. He's only a little older than me and has flown 105 aircraft types, many of them rare classics and warbirds. You can guess how he got his nickname!

I'm interested by the many variant aircraft that the Cub eventually spawned, from the Cub Special to the Super Cub to the Aviat Husky, but I have not flown any of them - until now. I recently had the opportunity to fly a brand new CubCrafters Carbon Cub SS, the newest and perhaps most impressive descendent of my humble J-3. Because I have no experience with the intervening and more equivalent aircraft, I can only compare the Carbon Cub with my own well-used 68-year-old club airplane, which inevitably pales in comparison. The Carbon Cub's empty weight is only 100 lbs heavier than the J-3, with 180 horsepower available vs. 75! But more about that in a minute.

I'll admit that I used my newfound "aviation journalist" status and accompanying press badge to score this little junket at Oshkosh. I did so on the advice of Jeff Skiles (most well known as the FO on US1549, but more recently a part of EAA leadership and a writer for Sport Aviation). Dawn and I hung out with Jeff for an hour at Oshkosh and afterwards sat in on an interview with CubCrafters' General Manager, Randy Lervold. Afterward Jeff arranged a flight for that evening and suggested I go up as well. "Being an aviation writer is all about collecting new experiences," he noted. "Airline flying and early career stories will only take you so far." Touché. Lervold immediately granted my request, though it was obvious I didn't have a Carbon Cub story in the works.


So on Monday evening, Dawn and I rode her motorbike to Hickory Oaks, a 2200' grass strip a few miles north of town that seemed to be in an entirely different universe than the bustling convention grounds. Five brand new Carbon Cubs sat prettily on the freshly mowed grass, looking perfectly at place as potential customers and sales reps milled about. The CC appears nearly identical to a Super Cub, as intended, but its underlying structure is in fact almost entirely different. It shares very little commonality with CubCrafters' Super Cub-derived Top Cub design. This is how it saves so much weight over the 80-year-old Cub airframe: a modern computer-aided design that eliminates unnecessary structure. For sure, there's some use of space age materials (cowling and spinner use the eponymous carbon fiber, for example) but it's still mostly a tube and fabric design. There's just a lot less tube than the Super Cub. Time will tell whether it makes a difference in durability. The Super Cub is so popular in places like the Alaska bush precisely because it's so over-engineered.


Lervold rightly points out that serious bush flying is not really what the Carbon Cub was intended for; that's the Top Cub's balliwick. The Carbon Cub was made for the recreational Light Sport market; the target audience is older, affluent, and downsizing into something fun that reminds them of the taildraggers of their youth while offering decent comfort and excellent performance. It certainly has that in spades; it is without question the best-performing LSA out there and arguably the most "airplane-like." This has stirred up considerable controversy in the LSA world. Like all LSAs, the Carbon Cub did not go through the rigorous Part 23 certification process; it was designed to meet less rigid ASTM standards. In order to qualify as an LSA, though, it was limited to a maximum gross weight of 1320 lbs and a max top speed of 120 knots. The airplane is clearly very capable of hauling much more and going considerably faster, and the Carbon Cub's critics argue that CubCrafters is promoting the airplane's performance with a wink and a nod regarding the certified limits.


They may have a point. As Lervold and Skiles climbed into the airplane for the first demo ride, I couldn't help but wonder whether an enterprising FAA inspector conducting ramp checks at this small grass strip would find the aircraft to be loaded within legal limits. In fact both Lervold and Skiles are relatively svelte men and the airplane had partial fuel, so I'm guessing the 424 lb useful load was observed on this occasion. I can't imagine many owners would be so fastidious. But is having the performance to exceed a limitation really a flaw? Most airplanes have a fair bit of margin built into their maximum gross weight. Pilots speak with admiration of designs that will "haul anything you can stuff in 'em." Conversely, underpowered designs seldom win fans, which is one reason most LSAs have not sold as well as the CarbonCub. I certainly enjoy a good extra bit of oomph even at sea level with a long runway, much less on the short, tree-hemmed, high-altitude strip that every potential Carbon Cub customer imagines themselves taking the airplane to. The old Cub has some very attractive qualities, but sprightly performance is not one of them. You fly it on the wing, not on the engine. It's worth noting that our club's J3 has almost the exact same legal useful load as the CarbonCub, and is also likely flown over max gross weight at times, but with a far more negative impact on safety margins.

Just from watching Skiles' takeoffs and landings it was clear I was in for a treat. When they returned, I took his place in the front seat, which felt fairly familiar as I usually fly the J3 from the front seat with Dawn aboard (it must be soloed from the rear). The instrument panel is roughly the same size as the J3 but packs in far more information using an interesting design. The airspeed and altimeter are conventional steam gauges; the digital tachometer, comm radio, and transponder are contained within similar compact round dials. Mixture, primer, light switches, and "magnetos" (actually dual electronic ignition) are squeezed around the edges of the panel. But in the middle is a large empty rectangle for mounting an iPad running Wing-X Pro, Foreflight, or similar software. Just about everyone I know (other than myself) uses an iPad for light plane flying these days, and the middle of the panel is a far better mounting spot than most setups I've seen. It's strictly VFR, of course, but it worked great.


The Carbon Cub on conventional tires has better over-the-nose visibility than the J-3, but this demonstrator was on 26" tundra tires, giving it a very familiar attitude and the necessity to S-turn to the runway from either seat. For my first takeoff, Lervold had me use 10 degrees of flaps (the J-3 has none) and an otherwise conventional takeoff technique of stick slightly forward to bring up the tail and then very light back pressure to fly. It happened about as quickly as you read that, maybe 5 or 6 seconds, during half of which I was still getting the throttle fully open! After liftoff I pulled up, and up, and up to a fairly nutty deck angle to achieve the Vy speed of 71 mph. The plane didn't have a rate of climb indicator, but I'd guesstimate it around 2000 fpm - remember, this is at max legal gross weight.


We flew a few miles northwest where Lervold invited me to explore the slow flight regime. The Carbon Cub maneuvered beautifully at partial flaps & 50 mph, including steep turns up to 45 degrees bank. At 35 mph I could still turn it without much complaint other than the occasional chirp of stall warning. Leveling the wings, I cut the power and did my best to get it to break into a stall. It finally did so, but the airspeed indicator was buried at the lower limit of 20 mph. I doubt that was actually accurate, but the VGs do keep the wing flying incredibly slowly. When the plane did break, it started to drop a wing but was easily righted with the powerful rudder. That was actually the biggest adjustment coming from the J-3; the rudder is considerably more sensitive. Other than that, the control feel was quite familiar, albeit with none of the stiffness or slop that comes from 68-year-old bellcranks, stretched control cables, and an out of square airframe. 

Maneuvering complete, we dropped down to Lake Butte des Morts and loafed along at partial flaps and 70 mph checking out the lake shore homes and boats - exactly the sort of sunset patrol that I take the J-3 on all the time, really the one mission at which the Cub thoroughly excels. It was quieter and more comfortable in the Carbon Cub, and I really enjoyed it, but I can't say I would have enjoyed it any less in the J-3. Landings on the other hand...whew, what a rush. Hickory Creek isn't really a STOL strip, not by Cub standards, but we treated it like one, turning base-to-final low between a strand of trees and a gravel heap that made the 45 mph approach speed seem a lot faster than it was. I nursed it over the boundary fence and chopped the last bit of power, brought the nose up to the attitude I use to three-point the J-3, put the stick in my lap as we touched down softly with nary a bounce, and very quickly rolled to a stop. Nice! Either it was beginner's luck or those tundra tires really soften out landings! We didn't bother back-taxiing for the next takeoff. Lervold had me use maximum performance technique: 20 degrees of flaps and stick back a half-inch, full throttle, and let the airplane levitate off the ground from a three-point attitude. CubCrafters claims a ground roll of 60 feet. That sounds about right, it was incredibly quick.


For the encore I did a wheel landing, this time being less aggressive about getting the airplane down and barely touching the brakes after another smooth touchdown; we still only used about 600 feet of runway. We taxiied back to the other Carbon Cubs, which had finished their own demo rides, and shut down the engine. Lervold complimented my flying (like any good demo pilot!) and remarked that I could put .5 hours of CC11-160 PIC time in the logbook. Dawn and I hung around for a while chatting with Lervold, Skiles, and the CubCrafters sales reps while munching on burgers, quaffing cold beer, and eyeing the pretty taildraggers sitting quietly in the grass.


A few days later I was headed home from Oshkosh in my underpowered, beat up flying club Cub, watching pickup trucks pass me on dusty country roads as I strained against a 20 knot headwind at 500' AGL. No iPad or GPS in this plane; my finger followed our route on an open sectional and I peered into the haze for a 300 foot tower that the chart said was somewhere out there. Afternoon thermals tussled the wings and sixty-eight years of oil and dope and sweat swirled about the cockpit. I opened the window and was instantly rewarded with a warm blast of freshly cut hay. I don't mind saying that I didn't miss the Carbon Cub just then. Don't get me wrong; it's a fantastic airplane, I enjoyed flying it, and if I ever strike it rich and have $200k(!) to spare on a fun new airplane, it will be on my short list. But though it's distantly derived from the Cub and looks similar to the Cub, they're really entirely different airplanes. The Carbon Cub is built to safely take you to adventurous and challenging places through modern engineering and superior performance. The J-3, on the other hand, turns entirely routine flights into grand adventures through its very inadequacies and anachronisms. Maybe someday there will come a time when a Carbon Cub makes sense for me. Till then, I'll be perfectly happy to just weasel the occasional ride!

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