Pelican's Perch #74:
Hurricane (Part 2)
AVweb's John Deakin concludes his two-part series on the Hawker Hurricane with this report of his first time flying it. As you'll see, it takes a lot of time just to get ready to go, but once it does, it does it in a Hurry!
Editor's Note: This is the second of a two-part series on flying the Hurricane. Read Part 1 first.
First, there is excellent news. The main electrical panel for the Zero has been repaired after my little smoke and fire event, and I should be able to test hop it today (10/7/03). The Hurry has been test-hopped, and found OK, and the Spitfire is "very close." All three should be flying again by the time this column goes public. Can't wait to fly that Spit!
Last month I attempted to cover the systems in the Hurricane. This month I'll try and give a bit of the flavor of flying this British bird, from a personal viewpoint.
Pre-Clean and Pre-Flight
The aeroplane (that's not a misspelling, it's British!) sits idle a lot more than I'd like, and this means a lot of extra work must be done before it's ready to go on one of its rare flights. The big hangars at the SoCal Wing of the CAF are not well sealed, and dust is pervasive -- getting into and onto everything. The first order of business is to clean it up. We could fly it and blow some of the dust off, but as soon as the airplane is rolled out, the photographers seem to come out of the woodwork, and we want it to appear at its best. Besides, the boundary layer protects most of the dust. Buckets of water and some rags will do the trick. With a little luck, some volunteers can be found who will fall for the old Tom Sawyer trick, considering it a privilege and an honor to clean this antique. During this process, I mumble a lot about how pilots should not fly such priceless aircraft when fatigued, but it doesn't do much good: If I'm not at least giving the appearance of helping, the free help tends to drift away.
The tyres must be checked for proper inflation, and the tank for the pneumatic brakes usually needs servicing, too. Care must be taken with this tank, for we fill it from big nitrogen tanks with up to 2,000 psi in them. It would be really easy to blow the little tank up, for it only holds about 300 psi at a maximum. Yes, our big tanks have the adjustable regulators on them, but if someone is not intimately familiar with how those operate ...
There is vast potential for doing great harm to these old birds, both on the ground and in the air.
I usually climb up and do a quick setup in the cockpit while standing on the wing: making sure the mag switch is off, turning on the pneumatic system and checking air pressure, centering the trims, checking the battery voltage, checking the parachute (and repack date) -- just general stuff. The fuel cap removal tool is stored behind the pilot's headrest, so I'll fish that out and check the fuel tanks for full fuel. Even if someone has just hopped it around the airport using only a bit of fuel from one tank, I like to fill it up, as even full fuel is very limiting. If there happens to be a gear problem, or something else that requires time to troubleshoot, I want all the fuel I can have.
Alert readers will spot a seeming contradiction in that statement. I've written elsewhere about fuel management, which often includes taking off with partial fuel for a number of reasons. There's an old saying: "The only time you have too much fuel is when you're on fire." I disagree strongly with that, because professional fuel planning rarely includes full tanks on some airplanes. Probably less than 1% of all 747 takeoffs are with full tanks. But like all old sayings, there is a germ of truth, and most of those old sayings (and old wives' tales) do have a history. Here is the classic case -- an airplane with "short legs." "Fill 'er up, please."
It's always necessary to remove the fuselage panel for access to the water tank just behind the pilot seat to check and refill it. It must be full for every takeoff, without exception. Either through design or a partially blocked coolant radiator, the big liquid-cooled Merlin will get too hot unless the taxi time and runup are done quickly. If it's not too hot before takeoff, it will be about the time the gear is coming up. That may have been acceptable in wartime, but we have an overpowering need to extend the life of these antique engines as much as possible. The spray bars make a huge difference.
So we drag a garden hose over to the airplane and top off that tank, too.
The panel on the right side is also pulled, to check the battery area and the emergency air tank for the pneumatic system. This one seems to hold up pretty well from month to month, rarely needing service.
By this time, it's time for lunch, and I don't miss many meals. By the time that's over, the weather has closed down, and we abort for another day.
Just kidding, although it happens often enough. Camarillo is known for the marine layer that often moves in during the afternoon, and moves out late the next morning.
A Moment Alone
You'll almost always see me spend somewhere between five minutes and an hour of quiet, uninterrupted time in the cockpit before starting. The length of time is directly proportional to the time that has passed since I last flew the airplane. I am deadly serious about a thorough mental review of every single "thing" in the cockpit, and while my lips may not be moving, I'm really explaining everything to myself and another person, an imaginary stranger standing on the wing who will fly it next, for the first time. If I cannot "explain" something this way, it's time to yell for help, or go get the book (such as it is). This is no time to be prideful. People often ask how I stay current in so many airplanes, and the truth is I don't. The physical act of controlling an airplane is almost entirely subconscious (some say I'm unconscious, but that's only when I'm asleep in the seat). But managing the airplane and its systems is usually not, unless you fly only one airplane, and fly it a lot. To me, every flight is "The First Time."
The Hurry has a little more room under the canopy than the Zero, so not only will my big head fit, but I can wear my brain bucket without excessive bumping up against the glass. I really prefer to wear one, not only for the obvious safety reasons, but they reduce the awful noise, and they keep the sun off my head and neck, keeping me cooler. The Nomex flight suit is mandatory, of course, even if I do hear whispers like, "There goes the big green pickle." Just jealousy, I tell myself.
Unfortunately, I can't wear my boots; the pedal configuration is just plain wrong. These old taildraggers need lots of footwork, and I find I really want to feel the pedals. This means running shoes -- not good in a fire, or a jump. So I accept the fact that if I have to leave the aircraft, and if the bailout is successful, I'm going to have two broken legs/ankles in addition to any other problems.
Starting the Hurry
I'm convinced we do too many battery starts in these old airplanes. The props turn slowly on low voltage, making starts more difficult, and the only way to handle a starting fire is to keep on cranking and get the engine going. Some of the battery starts are necessary, for there is often no reasonable alternative. We've long had an external battery cart at the SoCal Wing, but this is nothing more than a rolling platform with a number of normal batteries that may have been on the charger recently. At best, the voltage is still only 24 or so. We recently acquired a big old "Hobart" ground power unit that noisily puts out a full 28 volts, with enough amps to really spin the big engines. More and more, I find myself asking for that unit, at least for the first cold start.
All buckled in, fire-guard posted, external power plugged in, and by then a crowd has gathered. Many of them are there to watch for any mistakes on the start, and they will remind me pointedly of all of them, for weeks and months afterwards. There is no mercy. But the teasing is good-natured, for all of them will have their turn, perhaps with me watching and commenting.
One such opportunity came at an airshow with my beloved C-46 when someone else had the duty. When it came time to leave on the final day, with thousands watching, the poor guy got a huge bang out of the right engine. So embarrassing. That was bad enough, but I heard later he mumbled over the intercom, "I'm sure glad Deakin didn't hear that!"
What he didn't know is that I had just arrived in the Bonanza on other business, and I was standing right behind the right wingtip when the engine barked. The crew chief was at the right waist hatch, watching the start, and precisely at the moment it barked, he happened to spot me. I heard later that he immediately said on the intercom, "Deakin is here, he's right off the right wingtip!" The pilot whipped around, and sure enough, there I was, with a big grin.
I try to remember to catch the latest ATIS before I start any engine that is prone to overheating on the ground, so I don't have to mess with it before taxiing.
The Hurry starts funny, on two counts. First -- unlike most of these aircraft -- there is no "power primer." It's the old-fashioned Kollsman type, the same as you might find in an old Cessna 150, or the 140 in which I first soloed. Pull to fill, listen for the squish, and push to shoot the fuel through tiny pipes to the intake ports. Repeat as needed, usually four or five shots in this airplane. It doesn't hurt to wait for a minute or so, so that some of that fuel can vaporize, making combustion easier.
The second "funny" is the prop. It's an all-wood prop, which just boggles my mind on a big Merlin. It's very lightweight, so there is almost no inertia, and no flywheel effect, as on the big steel props, which often weigh over 1,000 pounds. The result is a distinctive jerky rotation, slowing down on each compression stroke, and speeding up after passing each top dead center. If the engine coughs and tries to start, but everything isn't just right, the prop has nothing to carry it through a few more strokes, so the engine stops almost instantly. Very strange, the first few times. I've tried a couple of techniques, and the one that worked the best was to first just turn the prop a few blades to make sure it will turn. This engine has no "upside down cylinders" like a radial, so there is little concern for a "hydraulic lock," but I still like to make sure it turns normally.
Then I prime it about five good shots, then turn the boost pump on, move the mixture to "run," then immediately back to "off," and turn the boost off. That seems to get some fuel in the intakes, and it pumps some fuel under pressure into the carburetor. My theory is that this procedure creates a nice unbroken fuel stream, so that once the engine fires, it will keep running.
Next comes the litany, "Please, Lord, don't let me screw up." Coming from me, it's probably heresy, but I'll take all the help I can get, and now things are getting very serious.
I turn the mag switches on, and then with my right hand crossing over to the boost pump switch, I push with two left fingers on the painfully inaccessible starter and ignition booster buttons. If I've done it right, the engine will bark into instant life just as I turn the boost pump on and quickly grab for the mixture control. The last time I did this, the engine went smoothly from zero to 500 RPM, and purred like a kitten there. OK, a big kitten. Some of my tormentors looked disappointed -- the crew chief looked ecstatic -- and a few applauded.
The airplane will move with near-idle RPM, so there is no need to wait for the oil temperature to rise to 40°C before we can exceed 1,000 RPM, as on the radials. As soon as the oil pressure is checked I'll signal to remove the ground power and chocks, and I can call for taxi. If I forgot to check the ATIS before, I usually cheat with, "We have the numbers." Yeah, yeah, I know, bad technique. But I know what the weather is -- I can see it -- there's only one radio, and that engine is heating up. We need to be ready, and get this show on the road.
Over the years, I've had a couple of people -- including tower controllers -- ask, "Say, aren't you alone? What's this 'We' business?" No, it's not the "royal we," and I usually grumble, "It's me and my airplane." The real reason is all those years with lots of other people in the cockpit. Old habits die hard.
A final check to make the sure the pneumatics are turned on -- pressure above 200 -- and "we" move out. Right after starting to move, it's a good idea to check the brakes with a short squeeze of the brake lever on the control stick (rudder pedals neutral to equalize the effect). At first, it takes a little extra concentration to remember that brakes are something done with the right hand and both feet, but it's easier than it might seem. Squeezing the lever produces a well-modulated amount of total air, and moving the rudder pedals to select how much goes to which brake is very straightforward, as long as you're thinking about it. Forgetting for a moment and tromping on the top of the rudder pedals has no effect at all on the airplane, but will cause an instant rise in the pilot's heart rate from the feeling of "No brakes!" Ask me how I know.
Best to frequently check the air-pressure gauge, inconveniently located on the floor ahead of the control stick. Oh, and remember where the handle is for the backup bottle. And remember that sudden application of brakes might nose the airplane over. There are no spare props; only a company in Europe that will make a new blade to order, for some obscene amount of money. Whose idea was this, anyway?
My takeoff litany (Controls, Instruments, Gas, Flaps, Trims, Prop, Runup) will be done before the start or during the taxi, so only a brief runup is needed. It's important to remember to center the rudder pedals during runup, because that's the only way both brakes will work. There is a very narrow center range where the brake pressure is equalized, and this can be seen by watching the needles on the air-pressure gauge. There are three: one for the system pressure available, and one for each brake. Squeeze the handle on the stick, hold it, and watch the pressure needles change as you wiggle the rudder.
Since it's not advisable to do a high-power runup unless you want to destroy the prop when the airplane noses over, a quick prop and mag check, a quick look at the engine cluster, and we're done. The takeoff clearance almost comes too soon, making me wonder if I've forgotten something.
In a Hurry
If you've done it right, there is almost nothing to do in this airplane when taking the runway. There's no tailwheel lock (nor does it retract). I run the anti-collision stuff anytime the battery is on. The transponder is on any time the radio is (notwithstanding the out-of-date AIM). There are no cowl flaps. And the radiator exit doors remain open until cruise. Boost pump on, then the one "strange" item to remember is the water pump for the spray bars, because by this time the coolant temperature will be rising quickly. Best also to move the little safety catch out of the way for gear retraction, but that's easy enough to catch when you can't get the gear handle to move after liftoff.
On the runway and cleared to go, many people like to hold the brakes and advance the power to about 30 inches, check the instruments, then release the brakes and bring it on up to full power. I don't care for the technique; I'd rather let it roll while doing that final check, and that's mandatory in this airplane. Of course, manifold pressure in this airplane is "Boost," and zero is equal to ambient pressure, or about 30" at sea level.
As soon as any reasonable amount of power is applied, there's enough airflow over the rudder that brakes are not required for directional control. In fact, even at taxi speeds and power settings, full rudder will usually produce a very small effect, so with a bit of finesse and anticipation, it's possible to taxi without brakes at all. It's a little hard to stop, though.
On the runway, the throttle is advanced, and the boost will come up from about minus-6 to zero for a quick check of the engine. This is a fair amount of power, more than enough to get off the ground, and the noise is incredible, even inside a helmet with a good headset. The individual pops from the short stacks are still discernable, but now they come much closer together, and are much louder, and you know it's going to get much "better."
Ever been to one of those monster truck shows, in person? TV doesn't even come close to doing it justice. There is nothing quite like sitting right behind a really big 12-cylinder engine with straight exhaust stacks only a few inches long. Every one of them can be heard at low RPM, and every one sounds sweet. As the power comes up, the vibration pounds the stomach like a big bass drum, and the bones literally resonate in sympathy. Many of the "hot water twelves" (Merlins and Allisons) are bolted directly to the engine mount structure without cushioning -- nothing to deaden the vibration. Even those with some sort of cushioning don't have much, giving the airplane a "harsh" feel, while radials are much "softer." Very hard to describe.
As the boost comes through 2, then 4, then 6, it's very easy to think, "Enough, already, I don't want more power!" But ever the fool, I want all the law allows, so I press on, going for 9. I'm not sure why the limit is 9 -- some manuals say 12, and I'm game, but it's not my airplane, either.
Soon after getting above zero boost, the senses are flooded with a huge blast of humidity, and the smell of water being sprayed on hot, oily metal. Very distinctive and quite normal in this airplane, from the spray bars flooding the radiators right below the cockpit. It's a very leaky cockpit, with daylight visible through the cracks in many places. Not good for a fire, but fires are prohibited, at least in my book.
Many fighters have a low gear-speed, but this one is ridiculous at only 103 knots. It's very hard to keep the speed down until the gear is up. It necessitates either a sharp reduction in power (which I don't like), or a fair pitch up (which I do).
There is only one lever for the gear and the flaps, so that lever is pulled left to select the gear, then the safety latch is pulled out of the way, then up to pull the gear, then back to neutral when the gear up lights come on.
The very first thing that becomes obvious is that the aircraft is very unstable in pitch. Any small movement will start the nose moving up or down all out of proportion to the input; and if the input isn't reversed, the pitch will continue at an increasing rate. It's very possible that a twitch on the stick -- then letting go -- would set up an ever-increasing pitch until the wings come off, but I wasn't really interested in testing that theory. While unpleasant, it is easily controllable -- it just takes constant attention. After my first flight, my first action was to run a weight and balance on the computer, using the weight data from the last weighing. But much to my surprise it all checks out, and it's within limits, even with the water behind the pilot. But I want a recount, so I'm pushing for a re-weighing. As that water is used up, the instability improves, but it never quite goes away. Another side effect of this is that when pulling g's, the stick forces get lighter. I'd have to check it more carefully, but it almost feels like the stick force reverses, and positive forward pressure is needed to "unload." FAA certification standards do not allow this, but this is an Experimental aircraft, where such standards do not apply.
No matter what the data says, this instability in pitch fairly screams at me that the airplane is tail-heavy, so regardless of any weight and balance data, I was not willing to take the airplane into a full stall, or even close. I did want to slow down until it was talking to me, so I climbed to 8,000 feet above the airport, put the gear and flaps down, pulled the power back enough to get a decent speed reduction while climbing, then eased it off further as I dropped the nose to a normal descent at about 1,000 feet per minute or so.
The first try was quickly aborted, because the prop looked like it was stopping, and my heart nearly stopped with it! I've never seen a prop go that slowly, except when deliberately demonstrating a stopped prop. I shoved the power on, and the RPM immediately recovered, as did my heart. In thinking about it, I realized it just looked bad, because of the prop gearing and the light weight of the prop. I told myself the engine couldn't possibly stop, and even if it did, I could probably dive and windmill it to a start again, and if that didn't work, I could hit the starter button. I told myself that several times, but irrationality prevailed. I tried another approach to the stall, this time keeping the prop going fast enough to be invisible, as props should be. Just proves there's a time to be logical, and a time to be irrational, and Mrs. Deakin didn't raise no stupid chillun. Invisible props are good, and you can take that to the bank.
The airplane started getting a bit unhappy at somewhere well south of 60 knots, nose still well below the horizon, and that was good enough for me. I figured on 75 knots into the flare, and in the end, that proved to be on the fast side. Like the Zero, it's got a wing built for lift and low stalling speed, and also like the Zero, it can turn smartly to outmaneuver an enemy. To my uncertain knowledge, the Zero and the Hurricane never mixed it up, but it would be interesting to try that. Perhaps someday ...
Bringin' It Home
With the unusual pitch characteristics, I was not interested in doing any acro, so I limited myself to a couple of rather tame steep turns to check the stick forces, and a couple of landing patterns at altitude, to check for surprises. There were none, so I returned to the airport, even skipping the infamous "overhead" approach. The airplane is a bit more slippery than I expected. I entered the downwind at 120 knots, and had some trouble getting down to 103 to get the gear down.
I ended up a little fast into the flare, maybe 80 knots, and it seemed to float halfway down the runway. Fortunately, that put me far enough away from all the spectators that no one saw me bobble and bounce the landing except the tower, who kindly refrained from comment. Normally, I'd have taxied back for another, but I didn't know how much water I'd used, so I quit for the day.
Time and circumstances did not permit another flight until some three weeks later. Someone asked, "Hey John, wanna fly the Hurry in the airshow?" The plan seemed to be to put the Hurricane and the Spitfire up together, with the Hellcat and a visiting Sea Fury for a four-ship formation for the closing act of the annual EAA airshow at my home airport, Camarillo, Calif.
Of course, I acted bashful for all of three milliseconds, and then consented with "Aw, OK, if you really need me." The idea was for the Spit to lead, I'd fly wing on him, then the Hellcat, and finally the Sea Fury. I had visions of a nice easy takeoff, each aircraft waiting for the previous one to break ground. (The CAF is getting away from formation takeoffs after the big crash at OSH a few years ago.) Then I hoped we'd go somewhere and orbit, waiting to be called in to do the show. That would give me a little time to get used to formation flight in this unique bird.
But the airboss wasn't interested in what I might want, for right after I broke ground I heard him call, "Fighters, you're cleared in for your first pass." Two things became obvious immediately. The Hurry is a lot slower than the Spitfire, both in climb and speed! I cut savagely inside to catch up, and barely made it as Steve Barber in the Spit turned base for the first pass. The Hellcat caught me about the same time, so we got into a reasonable three-ship for the pass. The poor guy in the Sea Fury never had a chance.
The second thing I discovered was that the Hurry is probably the most miserable formation airplane I've ever flown. Any change in power instantly pitches the nose up or down, and this, added to the natural instability, makes it a real chore to hold any kind of position. I had to carry nearly takeoff power to keep up, and also had to keep an eye on the coolant temperature and flip the water on anytime it got hot, which was often. Also got several reports of "Hurricane is trailing smoke," which added to the fun. It was really the water from the spray bars, of course. We got in three passes, and frankly, I was ready to quit. Formation flight is very hard work under the best of circumstances, and the adrenaline really gets to pumping during a show. The miserable flying characteristics of the Hurricane just added to the effort. As agreed, we broke up in the overhead approach, landing at about 15 second intervals, with the first airplane landing well down the runway and going to the end, the second a bit shorter, etc.
I'm told it looked neat to have the two British airplanes together, but my main focus was on keeping them apart!
In short, a terrible airplane, but I can't wait to fly it again.
Be careful, up there!