Sunday, January 18, 2009

The Planes of Mojave: Symmetry

If you were to poll both regulars and visitors to Mojave about the most beautiful plane on the field, you’d likely find that a little canary-yellow experimental named Symmetry would be the hands-down winner. One almost can't help but stop and stare, and the more one looks, the more amazing this plane appears. 

The sense of detail and workmanship is stunning. Engine cowlings fit together almost seamlessly, without a fastener in sight. The propeller has the translucent look of polished carbon fiber weave. Even sitting still, the plane looks like it’s moving. Is it any wonder that Symmetry was the featured aircraft for the Mojave Transportation Museum’s inaugural “Plane Crazy” fly-in and open house? As such, I caught up with designer/builder/owner Cory Bird and chatted about his work of art (that's him standing next to the plane in the photo above).

I should say a word, first, about where Cory works: he’s one of the team at Scaled Composites, and I think it really says something about the people who work for Burt Rutan to consider how many of them have designed and/or built their own unique aircraft on the side. To look at Symmetry is to come to understand the character of the man behind it: a plane like this simply doesn’t happen without the builder having a deep sense of beauty, painstaking detail, and patience.

It took Bird 14 years to design and build Symmetry. I asked him if it was an every-day project, and Cory explained “I started in 1989, it first flew in April 2003. Any airplane project, with a family with kids – I had three kids – you’re balancing between going to volleyball games and football games and working at Scaled for that long…it was, as much as I could, but there was a period in 1995 when I didn’t work on it for three years. It sounds like a long time from the time you start to the time you finish, but really there’s probably 15,000 man-hours in it, spread out over that time.” Fifteen thousand? Add to that character list “commitment” and “endurance”!




A thing of beauty generally doesn’t just happen out of random happenstance, there’s typically intent behind it. I asked Cory about his inspiration. “As you research aerodynamics, you pick up little tidbits about what you think the lowest drag airplane would be. The mid-wing obviously is the best place you can put the wing, and it becomes, then, a packaging issue of getting the pilot in there. They say a T-tail is supposed to give you a smaller vertical tail with some endplate effect, plus since it was a tail-dragger, I wanted it up out of the weeds. But really, the airplane was just carving out a model until you like it and you say, ‘Ok, well if it looks good it’s probably good.’ I didn’t spend a lot of time trying to estimate the performance of the airplane, other than doing everything I could…to make it as low drag as possible.” 

Ultra-low drag, very obviously, was one of Bird’s primary goals. “The other one was to try to do it as cheaply as possible. It’s a fixed-pitch prop, stock IO-360 200-horse angle valve [engine]. It has fixed landing gear, and that saves an awful lot of money and time.” The tail wheel, though, does retract. 

Originally, Bird intended the aircraft to be a single-seater, with the retractable landing gear that folded aft, the wheel wells sitting just behind the pilot’s seat. “But Patti, my wife”, he explained, “helped on every bit of this airplane, and I said ‘You know what? I think I can fit you in here.’ We sat in the garage trying to do different seating arrangements, different inclinations, things like that, until we got one that works. I said ‘I’ve got this one that works, and I’m gonna put the gear down so that you can go.’” The aft seat, Cory jokes, was molded around Patti’s posterior. He took a block of foam, carved into it, had her sit on it for a while until it hurt here or there, and then he’d carve a little more. In the end, the seat fits Patti’s form so well that she doesn’t even need a cushion to be comfortable. (Add “devotion” to the character list.)




Cory said, “I really, really enjoy the German sailplane technology and the craftsmanship that comes out of Germany. I spent a lot of time a Cal City and Tehachapi [both glider centers] just looking at every detail on a glider, thinking, ‘Well, you know, I can even do better than that.’ And then to put a big ol’ engine on there, too. That’s really what inspired me. I just wanted it as clean as possible.”

When the plane was finally ready to fly, there was still a bit more work to do. Bird initially used a wooden propeller from a 200 hp Vans RV-6, and on the first flight he could do about 180 knots before the engine would start to overspeed. That wasn’t fast enough, though. “I flew that for maybe twenty flights, and said ‘I’ve got to do something.’ I took the propeller off and carved into it by hand with mini-grinders and sandpaper and blocks and stuff like that, and got 13 more inchs of pitch and added three more inches to each side, so six inches to the diameter, and with that one fix I was able to get 60 extra knots out of it.” Symmetry will now do 240 kts at about 3,000 rpm. But the propeller that I was looking at, with the gorgeous carbon-fiber weave, Cory said was the same one! “There’s wood buried down in there.” Over the wood is “a lot of fiberglass, the carbon [weave] is there primarily for aesthetics, but there’s a bunch of carbon uni for bending and a bunch of plus/minus 45 glass; I was trying to match the stiffness of the wood that’s underneath.”




I wanted to know if Bird was planning on a follow-on project to Symmetry. He said, “This airplane was meant for learning. I came to Scaled back in 1985 as a shop guy, and didn’t know much about aerodynamics, didn’t know much about structure, about machining, and this allowed me to learn all of those disciplines. I don’t plan on going any more with this airplane, but I do have another project in the works. “It’s a much bigger airplane, that will do everything that this one won’t. It’s not going to be a show plane, it’s going to be a truck.” Cory explained that Symmetry has a few limitations, mostly relating to its fixed-pitch cruise prop and super-clean aerodynamics. The prop has so much pitch that on take-off, the engine power has to be limited, otherwise the prop blades will actually stall. As a result, it takes about 3,000 feet to “comfortably” get airborne. And on the other end of the flight, the aircraft has so little drag that it’s hard to slow down, and thus the approaches have to be fast and very shallow. This all results in the need for long runways, eliminating some of the small-town locations Cory would like to go exploring. “I like getting out in the middle of nowhere, landing at little airports, and in this airplane, I like to have at least 5,000 feet.” He said he’d next like to have a plane that, while it takes a long time to get there, “but you can take all kinds of crap with you.”

Besides the take-off and landing limitations, though, Bird clearly likes how his workmanship flies. “Once you’re airborne, it climbs like a bad boy. It just takes a little bit to get up to that.” Once in cruise, the speed, Cory said, really depends on how much fuel you want to burn. At 185 knots, Symmetry burns about four and a half gallons of gas an hour (do the math, folks, that’s a whopping 41 nautical miles per gallon while doing NASCAR speeds!). Opened up, she’ll do 246 knots while burning 12 gallons an hour (still better than your typical SUV’s gas mileage). At 185 knots, Symmetry has about 700 nautical miles’ range. Handling wise, Bird says that it has light controls somewhat like a Longeze. “I can fly feet flat on the floor in the worst of turbulence and it will just sit there and track perfectly straight. It really is a nice airplane to fly.”

I asked Cory why he named the plane Symmetry, and got an answer very different than what I expected. “I knew I wanted an airplane that started with ‘S’ – I don’t know why. Patti and I were driving back from the Reno Air Races one time, and we had a dictionary with us, and she started going through the dictionary. She stumbled across ‘symmetry’, and I thought, huh, symmetry, that’s kind of fitting because Burt, my boss, he builds everything asymmetric, that’s perfect.” 

Clearly, I’m not the only one that feels that Symmetry is a work of art. Cory said, “I remember a guy came up to me once and said ‘I’ve got some friends down at art museum on the Mall in Washington. This airplane doesn’t belong across in the Smithsonian Air & Space Museum, it belongs on the art side.’ Burt told me, when he first looked at it back in 2003, he said ‘You can’t fly this airplane, you’ve got to just look at it, you can’t fly it.’” I think I can speak for all those who saw Symmetry at Saturday’s Plane Crazy, and at this past year’s Veteran’s Day display (the photos here were taken at both events), and say that we really like to look at it, too.

2 comments:

Tom Stinemetze said...

In April 2003 my son invited me to the Tier One (SpaceShipOne) unveiling ceremony. While there he said "come on down to this hanger, there's someone I want you to meet." In that hanger were Cory and his wife and the most beautiful airplane I have ever seen. I don't care how close you get - it is PERFECT! The firewall is polished so bright that you think there are two engines in there. Absolutely astonishing!

Peter said...

I bet they could pull some really clean molds off that plane and have a waiting list of customers willing to buy a kit plane version! Of course, how many people out there would have the time and patience to reach the level of craftsmanship Cory did? Not that he needs to start a biz when he's got an awesome job at Scaled but has he ever thought of selling plans or anything?

I'd like to see some drawings of Symmetry. If I could get a basic orthographic I could model it in X-Plane and see how she flys! Would Cory share these or is he as secretive as Burt Rutan when it comes to his creations?

~Peter

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