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Plastic Airplanes – They’re Real & Flying

29 Aug

source: http://philip.greenspun.com/flying/plastic-airplanes

Plastic Airplanes

by Philip Greenspun, CFII in February 2006


For long cross-country trips with a friend and a dog, one really needs a 4-seat airplane. Buying a plane of any kind goes against the conventional (male) pilot wisdom of “If it floats, flies, or fucks… rent it”. And in fact nothing could be easier than renting a 4-seat Cessna 172. However the cost becomes prohibitive if one wants to hop from city to city and hang onto the rental airplane, not necessarily using it every day, for months at a time. For a bit less money and a lot more hassle, one can have a much more nicely designed airplane, of which the three best-known examples are the Cirrus SR20/SR22, Columbia 350/400, and Diamond DA40. These airplanes are fast and clean despite having the fixed landing gear that is essential for novice pilots. They also happen to be made of a mixture of carbon fiber reinforced plastic or glass fiber reinforced plastic. In other words, plastic! The author has owned the Diamond Star DA40 and flown it all over North America and the Caribbean (700 hours). The author current owns a Cirrus SR20 and has flown it from Boston to the arctic ocean in Nunavut then down south to Alaska before returning to Boston (200+ hours of experience). The author has enjoyed a brief demo ride in a Columbia 400.

The Cirrus SR20

I’ve written a complete review of the Cirrus SR20 based on my ownership experience. Below are some notes that I wrote up in early 2002 after my friend Gary and I went to Augusta, Maine for our first ride in a 600-hour demo SR20.

Traveling by plane turns out to be exceptionally convenient if you’re visiting an airport. So we rented a 27-year-old Cessna 172 to make the trip up there from Boston. The 1.5-hour ride in the Cessna would have been enough to convince anyone of the virtues of a modern airplane. As I put on my shoulder harness, a trim piece that holds the harness up against the roof of the plane fell off. Part of the instrument panel was loose on the lower right side of the airplane, i.e., right in front of me. After I adjusted my seat it refused to lock into position, calling to mind the following mournful August 17, 2001 Associated Press item:

PENSACOLA, Fla. (AP) — Cessna Aircraft Co. was responsible for a fiery plane crash that injured three people in 1989, a jury ruled in returning a record $480 million verdict against the company. Plaintiffs lawyers said the verdict — including $400 million in punitive damages and $80 million in compensatory damages — is the largest in aviation history. Plaintiffs claimed the crash was caused by a defective seat latching mechanism. The suit alleged the pilot’s seat suddenly slid back as he was attempting to land and caused the nose to pitch up because he had the control yoke in his grasp. The single-engine Cessna 185 then crashed and burned in a small clearing amid thick woods 75 yards from the runway at Coastal Airport, a small Pensacola landing strip. “Virtually everybody who’s ever flown a Cessna at least has had a seat slip of their own or has heard of a friend who has had a seat slip,” Arthur Alan Wolk, one of the plaintiffs’ lawyers, said in an interview.

Once we were up in the air, I kept looking for the panoramic view through an unobstructed Plexiglass canopy that I get from the Diamond Katana in which I train. Instead I found myself looking at roof support rails, wing struts, and the underside of the wing. The Katana gets toasty warm even on cold days, partly from the sunlight streaming in but mostly because the cockpit is tightly sealed and the cabin heat is powerful. The Cessna by contrast was so drafty that even with full cabin heat my feet were frozen and the rest of me, encased in a Goretex down parka, was chilly. My friend is an excellent conscientious pilot. Nonetheless the lack of a headrest in the seats and the easy-to-slip-out-of shoulder harness didn’t inspire any confidence in the survivability of a crash in the Cessna 172. Not to mention the fact that the airframe was certified long before the development of 26G European crash standards.

Anyway, we made it to Augusta. The Cirrus in the hangar was a beautifully finished machine and, despite its 600 hours, appeared brand new. Everything seems very logically placed and ergonomically sound. Entry and exit isn’t so easy, however, and involves stepping on the wing before going through a gullwing door. Back seat passengers have to work their way around the front seats to get in. It is sort of like riding in the back of a 1974 Camaro except that the seats are leather and you wear a 4-point harness with a slick and comfortable inertia reel on both shoulder straps. These 4-point harnesses are a welcome sight in a composite airplane. Aluminum planes crumple and absorb shock to some extent, which is why so many people have survived crashes in the seemingly dodgy Cessna 172. By contrast composite (plastic) airplanes are super rigid and the cockpits have remained intact after impacts nearing 100Gs. This means you may escape being crushed by collapsing airplane parts but the full force of deceleration must be absorbed by the seats and your body against the seat belts. With two shoulder straps instead of the standard single strap, the damage to ribs and organs should be considerably reduced. (Be careful when wearing these harnesses, though; they tend to drift up so that the lap belt is around your stomach instead of your hips.)

Occupants of the front seats get a more upright and comfortable position than Katana pilots. Legroom is ample. Though I’m 6′ tall I had to move the seat forward a bit in order to reach the rudder pedals. Visibility is excellent, much better than the Cessna 172. However, the gullwing doors necessitate thick door pillars on either side of the front cabin. This is a significant obstruction compared to the Katana’s canopy or the Diamond DA40 front canopy.

Dog owner alert: getting a big dog into the rear seats without risking scratches on the wing finish would require lifting/throwing the dog into the cabin.

How does it fly? Takeoffs and landings were pretty straightforward and controllable. Once up in the air, however, even this wimpy 200 hp version of the Cirrus proved to be terrifyingly fast. A moment of inattention in the 80 hp Katana and you’ve climbed 100 feet above your assigned altitude. The same moment in the SR20 and you find that you’ve drifted up 500 feet. Going from a 105-knot Katana/Cessna-class aircraft to a 160-knot plane like the Cirrus doesn’t seem like such a huge deal but in fact everything is happening much faster. It really isn’t all that practical to fly the Cirrus as slow as you’d fly a trainer. To get a noise measurement comparable to the C172 we wanted to cruise at 105 knots, for example. This required cutting power to such an extent that the cylinder head temperature was falling below the green arc. I.e., the engine was getting overcooled in the -7 C air. We ended up having to extend 50 percent flaps and increase the engine power. This might be the world’s easiest to fly 160-knot airplane but low-hour pilots will benefit from a fair amount of dual instruction.

The SR20 has a split-airfoil wing design that ensures the wings will stall near the fuselage first, leaving the outer wings and ailerons unstalled. The result is very controllable behavior right up to and including the stall. The Cirrus felt as least as good in slow flight and power-off stalls as the Diamond Katana trainer, though of course everything is happening 20 knots faster (The Cirrus stalls at 56 knots with full flaps, 65 knots clean; the Katana stalls at 37 knots with flaps and 41 knots clean). [Three months after my test flight, a couple of new SR-22 owners had a less happy experience doing stalls in an SR22; see NTSB accident report NYC02FA089.]

One of the most modern and beloved features of the Cirrus is its side yoke. This looks like a stick but works like a yoke. If you’re flying left seat, you operate it with your left hand. The yoke itself falls naturally into your hand when your arm is on the armrest. Push straight in and the nose pitches down. Pull straight out and the nose pitches up. Twist to the left and the plane rolls to the left. Twist to the right and the plane rolls to the right. The twisting effort will give your left wrist a good workout if you don’t have the plane precisely trimmed but fortunately trimming is made much convenient by the provision of a little 4-way trim switch right on the yoke handle. This looks sort of like the power mirror control on a car and you use it to adjust elevator and aileron trim. The same switch, if pushed straight down, will disengage the autopilot.

The side yoke is better than the huge “steering wheel” central yokes of most airplanes in that it frees up sightlines to instruments and displays on the panel. The side yoke is better than a floor-mounted stick in that it frees up your lap for holding charts and clipboards and so forth. All of this said, based on my limited flying experience I prefer the Katana-style floor-mounted center stick. With a true stick the same kinds of motions and muscles are used for all flight control. There is some support for this among experts. Here’s an excerpt from a 1998 USENET posting from Mary Shafer, SR-71 Flying Qualities Lead Engineer at NASA’s Dryden Flight Research Center:

“Right now side sticks are stylish, but many flying qualities engineers (like myself) and pilots are of the opinion that center sticks are better, at least in high-performance aircraft.”

How about the multi-function display (MFD)? It is certainly big and any computer nerd will tell you that the three most important things in user interface are screen space, screen space, and screen space. I had heard that it would be hard to read in bright light but we had no trouble on a fairly sunny day just after noon. None of us had any idea how to operate the MFD but its default mode seems to be to show a schematic map of your airplane plotted against the nearest airports. Very useful and comforting though maybe you could get much of the same benefit from a Garmin 530 mounted in any old plane. One thing that the Cirrus MFD does that the Garmin won’t is walk you through checklists.

Interior noise levels were moderate at low speeds, 83-84 dbA SPL at 105 knots (no flaps) against 92 dbA SPL for the Cessna 172 that we’d flown up. If you push the Cirrus up to 140 knots, however, the noise level also comes up to around 93 dbA. For some perspective on these numbers, note that OSHA limits worker exposure to 90 dbA for 8 hours and mandates periodic testing of workers continuously exposed to 85 dbA or louder noise. Noise above 70 dbA is considered fatiguing. A Honda Accord going 70 MPH generates an interior noise of 66 dbA.

A feature that we did not try is the airframe parachute. If the engine fails when you’re low to the ground and can’t see any reasonable landing strips, deploy the ballistic parachute and you and all of your passengers will float to the ground for a really-painful-for-your-insurance-company-but-maybe-not-so-bad-for-you landing. Experienced pilots tend to scoff at the utility of this feature and indeed only one of the 250+ Cirrus planes flying has ever required a deployment (see note at right). A good pilot would rather glide to a landing than destroy the airplane and hit the ground with a force that is compared to being dropped from 10 feet off the ground. But what about guys like me? Novice pilots? And what if some of the internal parts fail and the control surfaces become disconnected from the yoke or stuck? My friend Richard has flown roughly 1500 hours in 20 years. He says that only once would he have considered pulling the ‘chute. A mechanic had reinstalled fuel intake lines into the wing tanks of his Mooney 231 such that they could only reach about half of the fuel. So with the right tank fuel gauge reading 1/2 full, the engine quit at 6000’ above a tree-filled swamp. There were no roads. Fortunately Richard had a nearly full left tank and was able to switch tanks and restart the engine before the Mooney had glided all the way to the ground.

Today I have 1350 additional hours of flying experience and 200 more in the Cirrus. What can I add that isn’t in my review? The Cirrus is a great passenger’s airplane and it is a good airplane for people who want to get from Point A to Point B in non-icing conditions. The Cirrus is not fun to hand-fly and is not a good trainer. It is a good final airplane for someone who is never going to want to spend a lot of money on an airplane or want to go some place on his or her own schedule. A fair number of Cirrus owners would be alive today if they had saved themselves $100,000 by purchasing a 10-year-old turbocharged de-iced Mooney that can climb safely through potentially ice-filled clouds and get on top of the weather. Cirrus was started by a couple of brothers from Wisconsin, then sold to First Islamic Investment Bank, a group of investors from Saudi Arabia and Kuwait, in August 2001.

Diamond Star DA40

I’ve written a complete review of the Diamond DA40 based on my ownership experience. Below are some notes that I wrote up in early 2002 after Richard and I on a demo ride in a 2001 DA40.

“This has the best visibility of any airplane I’ve ever flown,” said normally grumpy Richard (the 1500-hour pilot mentioned above). Earlier in the day we’d spent 1.5 hours playing around in a DA20 Katana, which offers superb visibility through its clear canopy. The DA40 is better. The beltline is even lower than in the Katana. Because the DA40 is a four-seater, the wings are farther behind the pilot’s seat than in the Katana. The only way that you’re going to be more at one with the sky is in a sailplane. Handling the DA40 was a treat both on the ground and in the air. Despite having a similar castering nosewheel design, the DA40 is somehow easier to taxi than either the DA20 Katana or the Cirrus. Once in the air the familiar floor-mounted center stick was completely natural for someone like me who had trained in the Katana. The DA40 does not have aileron trim like the Cirrus and the elevator trim can be controlled either from a switch on top of the stick or, if that should fail, from a standard trim wheel in between the front seats. The top of the stick also has controls to disengage the autopilot or to reset the autopilot’s heading.

As a novice pilot whose trimming techniques are imperfect, I greatly preferred the stick to the Cirrus’s side yoke. On the Cirrus if I didn’t get the aileron trim correct, I was exerting a lot of force with my wrist muscles. If your trim isn’t just right in the DA40 you have the full power of your arms available. I also thought the stick was nicer and more intuitive for making radical aileron adjustments to compensate for winds when taxiing.

Surprisingly, the DA40 was easier to fly than the DA20 Katana. The extra weight and size somehow seems to make the airplane more stable during approaches to landing. And the DA40’s behavior in very slow flight, power-off stalls, and power-on stalls was predictable. Because there is no tendency for either wing to drop, it can be tough to tell that the DA40 is actually stalled. You’ve had the stick all the way back for awhile. The airspeed indicator has dropped below 20 knots. There is a very mild buffeting. But the plane still seems to be flying and the wings are level.

Experienced pilots will appreciate the DA40’s three engine controls: throttle, prop speed, and mixture. Not me, though. As a confused beginner, I’d like to have one control: power. The Cirrus and the old Rotax-powered DA20 Katanas are closer to my personal Nirvana in that each has two engine controls. Sound like a trivial point? We were doing touch and gos in the DA40. I (15 hours) was left seat. Chris (5000 hours) was right seat. Richard (1500 hours) was back seat. I forgot to push the prop speed control to max on final and the real pilots in the airplane didn’t notice. After we were rolling down the runway I pushed the throttle full forward for maximum power. The DA40 seemed to climb a bit less eagerly back up into the air. Only at 300′ above the ground did I notice that we weren’t in fact getting maximum power because the prop was constrained to spin at 2400 RPM. Why didn’t we end up testing the 26G safety cockpit in the trees of Lawrence? It was a long runway. It was at sea level. It was a cold January day in Massachusetts the air was therefore dense. But this is the kind of mistake that you simply can’t make in an airplane with fewer controls.

The DA40 interior is spacious and cramped at the same time. Getting in and out is easy. Front seat entry is similar to that on the Katana. You step on a special step and grab a handhold above the panel and then can step onto the floor of the aircraft. No need to step on the seats. Rear seat passengers have their own gullwing door (should be very handy for dogs). Once the rear seat passengers are in place, they have an awesome amount of space and plenty of legroom even for this 6′ tall person. Like the front seats, the rear seats are equipped with car-style 3-point inertia-reel seatbelts. The view from the rear seat is an amazing 180-degree panorama out the teardrop . This would be the ultimate sightseeing tour plane for groups of 3 plus one pilot (half fuel, no luggage, and make sure those 3 tourists aren’t too fat). I would have been happy to ride in the back seat all day.

What’s the cramped part? Sadly it is the pilot’s seat in a DA40, better in the 2002 and subsequent model years but still not comfortable for flights longer than two hours. The seat does not slide forward and back. Rather the pedals are adjustable as on a Katana. That’s fine except that although I’m only 6′ tall, the tops of my thighs were touching the bottom of the instrument panel.

Space between the front seats is in short supply in the DA40. In the Cirrus the seats are separated by a useful center storage console, sort of like what you’d see in a sports car. This is just big enough to keep Cirrus pilots from rubbing elbows. The seats on the DA40 are closer together.

Interior noise in the DA40 was approximately 92 dbA SPL at 125 knots indicated airspeed (full cruise power at 3000 feet). This was the same as the Cessna 172 at 105 knots. Slowing down to 110 brought the noise down to 91 dbA. At 105 we were at 90. By pulling the prop speed back to 2240 RPM and slowing down to 65 knots, we were able to bring interior noise down substantially to 85 dbA. Bottom line: looks like the Cirrus is the winner in the interior quietness department at slow speeds but at standard cruise speeds the planes are similarly noisy inside (of course the Cirrus is covering more miles per hour at its cruise). Both airplanes meet tough standards for noise pollution as perceived from the ground.

The Cirrus and DA40 have very different instrument panel styles. The Cirrus looks like it was injection molded and designed for mass production. A lot of the controls are comfy rounded plastic pieces. The Diamond looks like it was handmade by craftsmen. A lot of the controls are machined aluminum pieces. The Cirrus looks more like a car inside; the Diamond looks more like a traditional airplane.

One complaint that some people had with the early Katanas has been resolved to some extent with the DA40: roasting underneath the canopy during long taxis on hot summer days. The DA40 canopy opens from the back and has a special notch so that it can be left open during the taxi. Plus there are lots of windows and air vents.

An interesting feature of the DA40 is its modular construction. An aircraft mechanic can take the whole plane apart in a day and put it into half of a shipping container. Then you can ship the whole thing to Europe and reassemble it for a few months of recreational cross-country trips in the Old World. If you fly your DA40 to the London, Ontario factory they can take it apart and ship it over to their Austrian counterparts who will put it back together for you. The overall cost is probably in the same $5000 range as hiring a ferry pilot, buying ferry insurance, etc., but the aircraft is spared the 40 hours of pounding across the North Atlantic.

Diamond is owned by the Dries family of Austria, which was wealthy enough to invest tens of $millions in their Canadian expansion factory. So they ought to have reasonable staying power.

January 2005 update: After 700 hours of time logged in the DA40 I can say that this initial impression proved more or less correct. The plane was always a delight to hand fly. It was hot inside on sunny days. It was simple and inexpensive to maintain, with the exception of a couple of items that hadn’t existed on the earlier Diamond airplanes, e.g., the MT Prop and the KAP-140 autopilot. I ended up wishing for an adjustable seat with thicker padding. February 2006 update: I have been doing some flying with a local pilot who bought a 2005 DA40 with the Garmin 1000 glass cockpit. I wrote up some of my impressions in an Avidyne versus Garmin comparison.

The 2007 DA40 with the Garmin autopilot will be a truly great airplane. If you’re relatively rich and want a plane in which to get your Private and Instrument airplane, the DA40 is the perfect first plane to own. If you’re not quite as rich and lookign for a plane to lease back to a local flight school, the DA40 is a great choice because the plane is so easy to fly that the renters won’t wreck the plane and the insurance will be much lower than if you tried doing this with, say, a Cirrus SR20. If you’re buying this plane in which to get your ratings, don’t worry too much about the KAP-140 autopilot. The King autopilot is perfectly adequate for most purposes and you’re going to want to hand-fly most of the time. If this will be the last airplane that you buy, I recommend waiting for the Garmin autopilot.

Columbia, formerly Lancair

The Columbia planes are the fastest piston-powered aircraft made. They are also easy and pleasant to hand-fly. The Columbia 350 costs about the same as the Cirrus SR22 and, in most pilots’ opinions, is a superior airplane (though remember that the passengers would probably prefer the more spacious SR22 cabin!). The Columbia 400 offers the same capabilities as the Piper Malibu/Mirage: de-icing gear and the ability to fly up to FL250, above most of the weather. The 400 cabin is small compared to the Malibu’s 6-seat airstair-door cabin, and unpressurized, but if you want a simple reliable airplane in which to build experience in the flight levels, the Columbia 400 is a great choice. Buy a Diamond Star DA40 for 250 hours and your instrument rating. Fly the Columbia 400 for 250 hours for transportation, then trade it in on a Very Light Jet such as the Eclipse. Columbia has had a rocky financial ride, but after a recapitalization by Malaysian investors in 2003, seems to be doing well.

More:

Bottom Line (Cirrus versus Diamond)

The Columbia 350/400 are so much better than the SR22 and so much faster than the DA40 and SR20 that there is no point in doing a comparison chart. If you want to spend between $350,000 and $500,000 for a new fast airplane, you need to test-fly a Columbia (and also a Diamond DA42 and a Mooney). A lot of folks have trouble deciding between the SR20 and DA40, so a comparison between these aircraft is worthwhile. It is a shame that at prices approaching $300,000 you have to compromise, but you do. The Diamond Star DA40 is the pilot’s airplane, the Cirrus SR20 is the passenger’s airplane. The DA40 is fun to fly and gets into short runways. The SR20 is more comfortable and gets you from medium-length runway to runway substantially faster, especially if there is a headwind (and as you fly more cross-country trips, you’ll discover that there is always a headwind). The DA40 is good for learning. The SR20 might be the last airplane that you buy if your mission calls for a lot of 300 n.m. trips for two people in reasonably good weather.

In my experience, the DA40 is cheaper and easier to own. My 2005 Cirrus seems always to be afflicted with a mandatory service bulletin or airworthiness directive that has me ferrying it back to the nearest authorized service center where it will spend three weeks while they order parts, argue with Cirrus, etc. The Diamond factory was a lot more responsive.

Insurance for the DA40 was slightly more than half the price of SR20 insurance. (www.avemco.com is probably the cheapest carrier for the DA40).

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Posted by on August 29, 2007 in General Knowledge, Recreation

 

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