Thursday, 26 January 2012

Flying the T-6

One of the many good things about Attitude Aviation is the variety of exotic aircraft that you can fly there. You can fly a Pitts and even, with enough time, patience and money, get to the point where they'll let you solo it or take friends for hair-raising aerobatic rides. They also have a Waco, which is a huge, lumbering - but aerobatic - biplane of pre-WW2 design, and a Marchetti, which is a nice touring airplane that just happens also to be fully aerobatic, including inverted. Not to mention the L-39 which allows you, at eye-watering expense, to fly a jet.

And recently, they finally got their T-6 (also known as a Texan, or in the UK a Harvard) back on the line. This is another WW2 design, classified as an "advanced trainer". In those days, a 19-year old would start flying a Stearman, solo after a handful of hours, and after getting to barely double figures would find himself behind the stick of a 550 HP monster, the size of a combat fighter. A few tens of hours in that and he'd be in a Spitfire, Hurricane or P-51, in combat for real. And maybe he'd come back, too... or maybe not.

Attitude originally had the T-6 on the line a few years ago. I flew it a couple of times, partly to prepare myself for flying the P-51 - but that's another story. Soon afterwards it had a landing mishap. The saga of the repair work and repaint that followed makes for a very long story - but finally, two years later, she showed up again at Livermore airport. I felt I needed to do something to celebrate getting my commercial pilot's license, so the timing was perfect.

The first thing about the T-6 - compared to the normal small planes we fly - is that it is seriously big. The low-mounted wing is at chest height, and the canopy stands about ten feet above the ground. Getting into it involves first clambering up on to the wing, then hoisting yourself into the cockpit, standing initially on the seat before you carefully lower yourself into place. There are two beams for your feet, with rudder pedals at the ends, and underneath that a huge void. Whatever you do, don't drop something in there!  All the controls are massive. It feels truly indestructible. After all, they were made to take tremendous abuse from very inexperienced pilots.

It's also been said that they were specifically designed to embody every known defect of all the combat aircraft of the time. So no matter what you eventually found yourself flying, it would seem tame compared to the T-6. One thing to do the first time you fly a new type - especially if it's as different as this - is to get familiar with all the controls. This means sitting in the cockpit, manual in hand, making sure you know where everything is and what everything does. Maybe you even move some of the controls. But whatever you do, don't move the landing gear control. Because this aircraft has no protection against that - move it to the "retracted" position while on the ground, and it will obligingly tuck the wheels up under itself, doing a lot of expensive damage in the process.

Finally, you feel ready to go flying (with an instructor - this is not a plane that Attitude will let you solo). The first thing to do is start the engine. It's not like a car, this is not a trivial matter. First of all, the prop must be manually turned through a couple of revolutions. Big radial engines like this are notorious for getting puddles of oil in the lower cylinders. Oil being incompressible, if the engine starts like this, the cylinder will be wrecked. This would be highly embarrassing, as well as expensive.

That done, you can climb back into the cockpit, and do battle with one of the most frustrating pieces of equipment on the aircraft. Like most piston engines, this one needs priming - using a manual pump to squirt raw gasoline into the inlet manifold. But the pump is incredibly stiff, and once you're strapped in it's at arms-length. I confess to having been completely unable to unlock the pump, needing someone else to climb up and do it for me. Though not expensive, this is definitely embarrassing - a bit like not being able to release the old-fashioned parking brake on your first driving lesson.

Finally, four shots of primer, and the primer has been closed and locked again. The starter is, uniquely, operated by a pedal between the rudder pedals. As soon as the engine fires, you must get back smartish onto the pedals, to be sure the brakes are fully applied. At the same time, you have to get the engine actually running. Radial engines start one cylinder at a time, or so it seems. The first kick must be carefully nurtured, the throttle advanced very slowly, as (hopefully) another cylinder starts to fire, and another, to the accompaniment of loud bangs and the occasional flame from the exhaust. Watching someone else start a radial engine (and listening to it!) is a delightful experience. Doing it yourself is fraught, with the knowledge that if you fail you'll have to start over, including the dreaded primer.

Finally the engine is running smoothly, all cylinders firing. Now it's time to taxi. As you release the brakes and start to move, you realise just how huge this thing is. Luckily the brakes are conventional - not heel brakes, or the strange composite arrangement with a bicycle brake lever on the stick like on the L-39. But it can't be too easy. In a taildragger you want to keep the stick fully back all the time when on the ground (let's ignore quartering tailwinds for now). That locks the tailwheel within a narrow range of motion. So if you want to make a tight turn, for example to reverse direction in the runup area, you must release the tailwheel lock by moving the stick forward. But for takeoff, it's vital to have it locked. And of course sometimes  it doesn't just lock itself - you have to wiggle the aircraft to and fro, until everything is right.

So, you've been through the (long) pre-flight checklist, got the oil nice and warm, taxied into position, and you're ready to take off. This is the frightening bit - first because you have no idea how it will behave when you apply power, and second because once you've taken off, you will, sooner or later, have to land again. (A very experienced Pitts pilot once told me that it took him several hundred flights before his first thought on becoming airborne stopped being, "Oh, sh*t, now I have to land it!").

The T-6 is actually fairly docile as it rolls down the runway. It doesn't have any vicious habits. It does take some heavy footwork to keep it rolling straight, especially as you bring the nose up. And, unlike the Pitts, it rolls a long way - although it has 550 HP, it weighs a lot too. Finally it reaches rotation speed, and with a pull on the stick you're airborne.

We flew over to our usual aerobatic practise area, which gave some time to get a feel for the aircraft. The stick is quite heavy but easy to get used to. It doesn't have a lot of adverse yaw (unlike the Citabria, for example) so only modest rudder inputs are required. And it makes that wonderful radial noise as you putter along at a modest power setting and 130 mph or so. You just know that everywhere you go, people are looking up and thinking, "What's that?"

We did a few of the usual exercises with a new type, starting with turns and then steep turns. They're easy to fly, the forces, while heavy, are consistent and well balanced. Then we went on to simple aerobatics - loops and rolls. These, too, went easily enough. It takes a lot of force on the rudder to keep a roll straight, and because the roll rate is not very high, the loop finishes with the nose pointing distinctly downwards. Loops go nicely enough, diving for 180 mph then pulling round at 3.5G or so.

Once in flight, the T-6 flies fairly unremarkably. You forget its size, since it doesn't really matter up there. The panel is typical of its era - there's no six-pack, just instruments and switches dotted about at random. The landing light switches, for example, are on the left of the main panel - while all other lights are on their own panel on the right side of the cockpit. (I confess that I didn't find them in flight when I wanted them). The fuel gauges are even worse. They're purely mechanical, with sight gauges down in the void under the floor on either side of the cockpit. Before strapping in I did manage to locate them, but I found reading them in flight to be impossible. The gear lock confirmation is similar - you have to look through two tiny windows in the upper surface of the wing, to see the yellow lock pins. I said I could see them, and at the time I convinced myself that I did, but to be honest it's pretty questionable.

We did a couple of stalls, which were also unremarkable. Then it was time to go and land - with a wonderful view of Mount Diablo in the setting sun. I had an unpleasant experience landing a much smaller vintage taildragger a couple of years ago, so I get a bit apprehensive at this stage. With the T-6, the plan was to wheel-land it. Smaller taildraggers are normally landed on all three wheels at (much) the same time, but with bigger ones it's common to land with the fuselage level, just on the main gear. This means that the wings are still flying and will happily bounce back into the air if the tail drops, increasing the angle of attack. So you have to "stick" the airplane by pushing the stick forward at touchdown. Timing and finesse are everything - too late, and you bounce. Too early, and you thunk painfully hard into the runway - and then bounce. Too much, and you can ding the prop as the nose drops towards the runway.

As it turns out, the T-6 is a pleasure to land. Maintaining a steady 95 mph on final, just gently lowering the main gear onto runway then pushing the stick forward give a gentle touchdown. It's much easier than a wheel-landing in a Citabria!

The flaps on the T-6 are odd in a couple of ways. First, they're "split flaps" - all of the action happens under the trailing edges. From the cockpit the wings look solid, and when you move the flap handle, nothing visibly moves. All the action is underneath. In consequence, it's easy to forget to retract them after landing. And if you forget them until after shutdown, you have a problem. They are operated by an engine-driven hydraulic system, and once the engine has stopped, the only way to retract them is with a manual pump somewhere in the bowels of the aircraft. Guess how I know.

We did a couple of touch-and-goes, which went rather well, then we returned to base. My one real landing didn't go so well - I dropped in hard enough to elicit comment, rather than the smooth touchdown I'd managed earlier. And I'm afraid to say I was a bit heavy-footed on the rudder. I think I've got so used to the Pitts, which is very controllable and reactive on the rollout and will forgive a surprising amount of clumsiness, that the much more leisurely response of the T-6 caught me unprepared.

So, finally, it was back to Attitude, and engine shutdown. The sun was just setting as we landed, so the usual post-flight photo opportunity gave some nice sunset-type shots.

And some time, I really will have to spend some time just getting comfortable with landings. Apart from that the T-6 is a pussy cat, albeit a very big, heavy (and expensive) one.

Tuesday, 24 January 2012

Solar Power - so far, a mixed success

One of the unexpected benefits of losing my job was that my wife, who had taken over paying the household bills, took a close look at the power bills and had conniptions. She decided right there to get a solar power system installed.

This was quite an undertaking - the roof was getting old so we decided to have that redone at the same time, which in turn involved overhauling the solar heating panels for the pool which were there. The couple of weeks before Christmas were extremely noisy and dirty as big, strong men jumped up and down on the roof.

Now, the installation is complete - well, we've paid all the bills anyway. PG&E came by yesterday and installed the new meter, so now we can sell them electricity, That's good. But sadly, it isn't actually working completely, and it's not clear whether the problems can be fixed. That's not so good.

The system consists of 26 separate panels mounted at a slight angle on the roof, facing slightly east of south. Why they didn't make them face true south, I have no idea. We went for the highest-tech system on offer, using high grade panels from SunPower, each with its own inverter. This allows each panel to function separately and optimise its use of the available light, rather than wiring them in series so the output is always set by the weakest. This also allows us to get accurate real-time reporting of the power generation. At least, it should.

Our first problem is some trees on a neighboring property. In the winter (i.e. now), they start to shade the panels from about 11.30. From the pretty graphs the system produces, I can see that we're losing about a third of the production due to those trees. Generally I like trees, and I don't particularly want them cut down, even if the neighbor would agree. What is really annoying, though, is that if the panels had been placed differently on the roof, the shading would not have been as bad. This is something that the survey should have caught, and didn't. Once the sun is higher in the sky, I guess from some time in March, this won't be a problem. But still, it is probably going to lose us 10% or so of the total annual production.

The second problem is with the "fancy technology" part of the system - specifically, the Envoy box that monitors the panels and sends the data off to a company called Enphase. This is a Kleenex-box sized gadget, which communicates with the panels over the power line. This makes perfect sense rather than running a second set of cables. Or at least, it would make sense if it worked.

Initially this box was in my office, next to the router which it also needs to be connected to - by a cable, since for some reason they didn't use WiFi. That didn't work because the data-over-power couldn't get a good enough signal. So they moved it to the garage, close to the breaker box. That meant installing a second, completely separate, powerline bridge to carry the data.

I've always been suspicious about data-over-power. The idea of mixing all those tiny, sensitive little data bits with all the noise, inductive loads and general mess of electric power just doesn't seem like it should work - try connecting an oscilloscope to your power line and you'll see what I mean. I suppose I should feel reassured that it doesn't work. It's just that I'd rather it did.

Two of the panels simply don't show up on the Envoy. When I queried this, it turns out that the data signal to the panels isn't strong enough. "You'll have to move it to an outlet closer to the panel," the installer said. Well, but there isn't one. I tried anyway just moving it to another outlet. (The thing takes up two outlets, incidentally, and must not use any kind of an adapter or extension cord). But this time, the powerline bridge didn't work. And given that, there was no way to find out whether the communication to the panels was any better or not.

For now, we're stuck. The controller can only see 25 out of the 26 panels which are installed, at great expense, on the roof. It isn't clear to me whether the 26th panel is actually able to generate any power under these circumstances - since it's the one that receives the worst shade, maybe it doesn't matter much!

Even with the system as it is, there's a certain satisfaction to paying less to PG&E each month. But it would be even better if it worked properly, considering what we paid for it.

Tuesday, 10 January 2012

Instrument Flying by Helicopter

My latest flying training project is to work towards my commercial helicopter license (CPL-H). Having, finally, got my airplane commercial a couple of months ago, it seems like an obvious thing to do. So my plan over the next year or so is to gradually "tick all the boxes" for the experience requirements for the CPL-H, as described in FAR 61.129(c).

One of these is to get 5 hours of "actual or simulated instrument flying". Since our Robinson 44 is not allowed to fly in actual conditions (i.e. in clouds), this means flying "under the hood", using a gadget which restricts the pilot's view to just the instruments. This is how most instrument training and currency is done, even in airplanes, since you can't really count on clouds to be there when you need them, especially in our part of the world. Yesterday I completed my second helicopter flight under the hood, amounting to a magnificent total of 3.4 hours so far.

In a plane, with its high glareshield, there are lots of effective ways to limit the pilot's view. I use something called "Foggles" which are like industrial eye protection goggles with most of the lens covered in a translucent film. Only the bottom part, corresponding roughly to the reading part of bifocal glasses, is left clear. As long as the pilot isn't actually trying to cheat, these do the job very well. In fact, it's surprisingly easy not to cheat, assuming your goal is to be trained rather than just to pass a checkride. (In the latter case, it isn't really worth trying to cheat because the examiner will notice immediately). I remember one flight, on my own in actual cloudy conditions, where I popped out of the cloud and it took me a while even to realise that I didn't have to rely on instruments.

In the helicopter, it's harder to do an adequate job of restricting vision, because the visibility is so much better. The only thing that works - and then not very well - is the decidedly steampunk Francis hood, looking like something a submarine commander should be wearing. Even so it's impossible not to see ground through the lower part of the canopy - you just have to try not to notice it.

Flying the helicopter under the hood is much harder than a plane. For a start, you can't take your hands off the controls. A plane will cheerfully fly for tens of seconds, hands off. You sometimes see a plane referred to as a good "instrument platform", meaning that it is naturally stable. My own Cessna TR182 falls into this category. The heli, on the other hand, always requires a hand on the cyclic (the up/down/sideways control corresponding to the stick or yoke in a plane). Normally it's your right hand, but you can switch hands if you need to, for example to twiddle the Garmin 430 in the usual R44 instalation. Even that is tricky - it's difficult to fly as smoothly with the "wrong" hand (I guess left-handed helicopter pilots may find the opposite, but probably not - it's all a question of habit). And you have to be constantly prepared to get a hand on the collective really fast if the engine stops, to enter autorotation in the couple of seconds you have before the aircraft simply drops out of the sky.

Flying, and especially instrument flying, involves a lot of fiddling round with bits of paper - charts, approach plates and so on. It is very difficult to refold a flimsy IFR en-route chart with just one hand. For this reason, IFR-approved helicopters have either a crew of two, or an autopilot (or both of course). But helicopter autopilots are eye-wateringly expensive - little change out of $100,000 - and anyway not available for training aircraft like the R44. So, even during an instrument checkride, the instructor (or examiner) can be used as an "autopilot".

I've done a lot of airplane instrument flying, both under the hood and in real clouds. Much of it has been partial panel, i.e. without a functioning attitude indicator, which generally mysteriously "fails" at the very start of my instrument currency flights. So much so, that I've got used to flying without using it very much - the turn coordinator and the altimeter work just as well. That absolutely does not work in the heli, at least not at first. It is so much more sensitive that the AI absolutely has to be the primary reference all the time, just like it says in the IFR manuals. It took me a little while at the start of my first flight under the hood to realise this. Once I did, my flying became a lot more stable. In an airplane, quite a casual instrument scan works fine. But in the heli you really have to be moving very quickly between all the instruments. It takes only a small distraction to suddenly find yourself in a 30 degree bank or a couple of hundred feet off altitude. This is especially a problem when tuning radios or fiddling with the GPS - you have to scan back and forth between the AI and whatever you're twiddling, making the latter just an extra part of the scan. It's hard.

Once cruise flight is mastered, or at least under control, the next thing to tackle is approaches and holds. In principle an approach is just flying, but there's a lot more to keep track of - altitudes and headings change, and there's radio work too. A general problem with instrument flying is what happens when you get overloaded. You can go very quickly from feeling comfortable to being on the edge of complete panic, not because anything has gone badly wrong but just because there is so much to keep track of. Then small things start to go wrong - altitude and heading deviations, maybe a bit of an extreme attitude - and that piles on the workload too. It takes self-discipline to take a few deep breaths and get back to focusing on basic flying, get straight and level again, go around if you have to. For some reason the hood adds to stress too - flying in actual clouds, without the hood, seems less daunting. This may be just a very basic animal reaction to not having complete vision.

The handful of approaches I've flown have worked out pretty well, all things considered. My first helicopter ILS was the long, long descent into Moffett (KNUQ). Although it's charted as a series of step-down fixes, in practice you can fly the whole thing down the glideslope, all the way from HOOKS - 20 miles out and 5500 feet above the field. It's probably the longest ILS descent in the world, 15 minutes or so of following the needles. Fixed-wing, I flew it once with everything covered up except the VOR head - everything done by making tiny corrective inputs as the needles start to drift. It's a great exercise, but I'm certainly not ready to do it in the heli just yet!

What next? I only need one more flight like this to "tick the box" for my CPL-H. A helicopter instrument rating is pretty useless, since it's unlikely that I'll ever fly one that's equipped for IFR. But there again, it might be fun to do after the CPL-H - amazingly, it only requires another 10 hours of hood time to meet the legal requirements.