April 16, 2004

The Decathlon

A cool, cloudy morning in Oakland, with rain forecast for much of the Bay Area. The plan is for Ben and me to take 36B out to Tracy (KTCY) to introduce me to aerobatics in Cecilia Aragon’s Super Decathlon –- a sportier plane than 36B, and (as Ben puts it...) "a real taildragger, a real aerobatics plane". The weather looks ominous to the north with heavy rain showers over Berkeley, but by the time we’re over the Diablo and Livermore Valleys it’s fine, just some nice scenic little fluffy clouds here and there (and I end up being unable to put that damn The Orb / Ricky Lee Jones track out of my mind for the rest of the short flight).

On takeoff from runway 15 at Oakland, we try a trick Ben recently learned in a Super Cub: instead of raising the tail when the speed picks up and lifting off at the usual speed and attitude (on the mains with nose level, at somewhere around 50 – 60 knots, no flaps), we'll stay in three-point (tail down) attitude, and at 40 knots we'll quickly put in 20 degrees of flaps. The results are astonishing –- as soon as the flaps go down at about 40 knots with the tailwheel still on the ground, 36B leaps into the air in three-point attitude, and a few seconds later after I've lowered the nose a bit and retracted the flaps, we're climbing normally through 300'. We took off in the first two hundred or so feet of 15, less than half the normal takeoff roll using the POH-approved normal short field technique (OK, the headwind helped here, but it was still an eye-opener). A known and well-practiced short-field technique for bush pilots flying things like Cubs, apparently; the translation to the Aerobat works nicely, as Ben suspected. I'm not going to do this every day, but it's nice to know....

Super Decathlon N411DW at Tracy Flight CenterThe flight out to Tracy goes well, and we tie 36B down in the vast parking area in front of Tracy Flight Center, the FBO. It's quiet out here -- a decent-sized airport, but without much traffic -- and the TFC staff are friendly and efficient. They know Ben well, and help us get the Decathlon out from the FBO hangar with a minimum of musical planes. I meet the airport cat, a friendly thing variously named "Missy" or "Six" (she has six toes), who's locally famous for actually enjoying being taken for short flights. She strolls purposely past us onto the ramp towards the turbine Twin Commander near the fuel pumps.

There's an official aerobatics box just to the immediate southeast of the field, but we'll be doing our aerobatics in an informal box a few miles further to the south east (the formal box is too low for non-competition work, with a ceiling of only 3,000' and floor of 500' -- I’m not comfortable at the moment below 4,000’ AGL). We taxi to 30 and I take off, a bit unsure of what's going to happen. But the Decathlon’s a revelation: responsive, fast, easy to maneuver, relatively powerful (with that 180 HP engine), and a delight to fly. The constant speed prop helps a lot with aerobatics -- just set (the RPM and manifold pressure) and forget, unlike with 36B where you spend a lot of time pulling and pushing on the throttle with the fixed-pitch prop to ensure you don't redline the engine in a dive. The Decathlon has a stick rather than a yoke, and tandem seating; I start out thinking I’m going to find the stick (and the throttle placement at elbow height on the left side "door") weird and difficult, but except for a tendency to over-control in the first few minutes, I found the controls responsive, intuitive, easy to use, and -- for whatever reason -- easier to correlate with what you see outside than a yoke system. After a few minutes of doggedly watching the ball and turn coordinator, I just watch the horizon and fly by feel. Much easier -- and the way it should be. On the ground, the Decathlon doesn’t have 36B’s tendency to wander unstably from side to side at high speed (leading to that 36B rudder dance and great potential for ground loops...), and in the air it has much more rudder and elevator authority than 36B. Again, this means I tend to over control at times, but it's a more intuitive plane to do aerobatics in than 36B. The 180 HP engine is also a lot more powerful than 36B's 110 HP (but still way underpowered compared to, erm, real aerobatics planes...), and I'm surprised at how easily it climbs -- in fact, we actually slowly gain altitude through the series of maneuvers, when in the same situation in 36B we’d lose several thousand feet over a few minutes. The Decathlon could get addictive... if it weren't so expensive to rent.

In the informal box I first try a tentative aileron roll, just to see what happens. Well, nothing much bad happens, but the results aren't pretty because I'm still a little unused to the sight and the controls. But from the second roll on, through  a series of rolls in both directions, loops, barrel rolls, hesitation rolls, half Cubans, etc., singly and stitched together ad-hocly over about 25 minutes, it's all really enjoyable and (mostly) under my control and not too inaccurate. Cool! One thing that bothers me is that I'm ambidextrous (or rather, very weakly left-handed), and my instincts are to fly the stick with the left hand. But in the Decathlon you have to use the left hand for the throttle and other engine controls, and through the first few figures I find it unnatural and quite "wrong" to use my right hand. What happens over the next few minutes is apparently typical -- I end up using both hands in maneuvers, the left clasped around the right. This gives extra leverage, and since the constant speed prop looks after itself, it works nicely. I don't even notice I'm doing it until about half way through the session. In level flight I still have to fight the urge to grab with my left hand, but I'll get over it eventually.

Then we try sustained inverted flight. You can't fly 36B inverted for more than a second or two because its fuel and oil systems aren't designed to work when the plane's upside down -- it's all gravity-fed. The engine just sputters to a stop (and restarts immediately you go upright, luckily enough). But the Decathlon's built for inverted flight -- and it has near-symmetric wings to help with this -- and I'm up for it. Intuitively it's easy, but in real life it's surpisingly difficult to overcome the urge to pull the stick back and split-S down and (dangerously fast) back out the right way after a couple of seconds. It takes significant forward stick pressure to sustain inverted flight once you've rolled inverted, and with all the control effects reversed, hanging there against your straps with the windshield full of an upside down world, things can get a little disorienting (a tip from personal experience: it's also quite uncomfortable unless you've strapped yourself in really tightly). I try this about four times, with the last two attempts being pretty successful, sustaining in both cases about ten or 15 seconds inverted, level and stable (this is a lot longer than it sounds when you're actually doing it...). Cool! This could also be addictive.... One of the more popular tricks is apparently to roll inverted a few hundred feet AGL on departure and fly inverted to the aerobatics box. I don't think I'll be doing that anytime soon, but it's something to aim for one day... maybe.

After about 30 minutes of aerobatics we return to Tracy, where I embarass myself by lining up for 25 rather than 30 on downwind (D'Oh!). Ben gently points this out, and I get on the correct downwind. I feel really stupid -- I haven't done this for years (not since I was a student, I think). My pathetic excuse is that the Decathlon has no heading indicator, so I didn't do the usual HI vs runway heading sanity check before joining the pattern. On base and final I start obsessing about the landing -- an unfamiliar aircraft (with no flaps!) and a tailwheel at that. But it all goes fine with Ben talking me down, and I do a decent full-stall three pointer on 30 without killing anyone or breaking anything obvious. A lot easier to land cleanly than 36B, again mostly because of the better control authority and stability, but also because the landing gear feels a lot less springy. An observation: the stick overcomes the tendency of bad pilots like me to use the yoke as a steering wheel on landing (the bane of instructors everywhere); this can't be a bad thing.

In a corner of the hangar there's a little green and white Taylorcraft or Luscombe being worked on. The cowl's off, and right there on the front you can see the tiny four cylinder 65 HP Lycoming engine in all its air-cooled glory (and there's one of those little chrome venturis on the pilot's side exterior for the gyro instruments). I'll never complain about 36B's engine again... (nor about its gyro instruments, which are actually usable if you haven't been doing aerobatics). Across the hangar there's a sleek-looking Bonanza with a four-bladed Q-tip prop and a turbine conversion. Nice if you can afford it. How the other half lives, I guess....

The return flight to Oakland in 36B is uneventful. Over 580 near Livermore I watch a couple of radio-controlled model airplanes doing aerobatics on the little RC field a few thousand feet below us. Tiny things, they buzz (I can almost hear them...) around quickly and seemingly randomly, but easily visible from our altitude. My guess is they're actually a lot harder to fly accurately than a Decathlon or Aerobat, if only because everything's done remotely and things happen so quickly. Apparently there's a whole genre of model airplane aerobatics -- at least judging by the results when you Google for specific aerobatics terms: the top page or two of results typically point mostly at RC aerobatics pages). The landing on 33 at Oakland goes well -- a standard full-stall three pointer -- until about a second after landing when we suddenly billow several feet back into the air, even though the yoke is fully back and we landed stalled. I firewall the throttle and stabilize the aircraft at about 5 feet AGL, then re-land a few hundred feet further down 33 with yet another three-pointer. This time it sticks. I look at Ben to see what I did wrong, but he looks as surprised as I am -- I didn't do anything wrong this time, maybe we just got hit by a freak gust? Odd.

Super Decathlon N411DW at the fuel pumps, Tracy


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And all this has exactly ... what? ... to do with getting my instrument rating?! Nothing much (I'm not one of those people who believes that aerobatics training improves your basic ability to fly a plane in IMC or without external visual references), but it sure keeps the visual flying side alive...

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