In depth: Displaying a historic aircraft at Airfield Falls

Kevin: I'm here with Thomas Taylor and Jeff Koke of Datum Engineering. They are the Structural Engineers for Airfield Falls, a conservation park over in Fort Worth. And in particular, what we're going to be talking about, is all the unique thinking that went into this dramatic display of a set of historical jet parts that will be the, kind of, main object and feature in the conservation park. At Airfield Falls, what we've been tasked to do, is bring people into contact with new kinds of conservation prototypes together as a new kind of demonstration park. The one exception to that, is the fact that the actual location of the site is roughly 200 feet from what was once the historical entrance to Carswell Air fares, Air Force Base. One of the major strategic air command locations that protected North America during the Cold War, it's now a naval air station. And through that the project has inherited some pieces and parts of a historical jet aircraft. So the pieces and parts that we were challenged to design and display, consisted of a pair of wings and just the tail section of a C9 transport jet. And they had been physically separated. They were actually sitting out on the site. The tail section had been taken apart from the fuselage. We don't really know what happened to the rest of the aircraft. But our as, our, our challenge was, is how do we, how do we display them? Do we display them separately? Do we put them back together? So we chose to put them back together in their same original relationships, to allow people's imagination to fill in the rest of the aircraft that's missing. The challenge is, is all of the structural integrity of the prior aircraft was lost, because it'd been cut apart. Our first sort of impulse was to display them dramatically, as if they're kind of doing an aerobatic maneuver. And I showed this particular design to Thomas and to Jeff Koke, and they had some very interesting reactions to it. Thomas Taylor: obviously, the first, the first really major challenge is the fact that the wings have been cut in half at maximum stress. So, putting the wings back together in some manner was a really difficult challenge, and then I also had to make it a sculptural form, that that Kevin would like. This one, of course, is kind of a big monster sail trying to take a tremendous amount of wind. But at at the same time it's a very attractive structural form, so we wanted to, kind of, deal with it the best way we could. We felt that if we could rotate the wings and kept the, the wind forces of the ten-story building, so-to-speak, down, that that would be helpful. But then, we would have to come back to Kevin with a, a sculptural system that he would like quite a bit. Or as much as this and hopefully more. Kevin: Mm-hm. Thomas Taylor: So, we want, that was one structural solution that we wanted to solve. And what we did, Jeff built this little model, but this other model it's a very crude model. We don't build great presentation models like Kevin does. These are primarily in-house models that we use for studying. And, and our first model was a tripod and these vertical, these members traditional tripod would be sitting out, sitting out in front, and that would be the most stable, logical, structural solution. But it looked like the plane was trying to put its brakes on, rather than take off. So Jeff went back and we modeled the, these elements in a, in a swip, swooping backwards format, so that it had a more dynamic takeoff appearance. And the way we ultimately decided to solve that, because it, it created additional flutter, not just in the wings. The structure itself now wants to, to flutter a bit, because the legs are swooping back. So we concluded that we wanted to tie it down with with wing tie rod, tie downs, which is an aircraft kind of. Kevin: Right. Thomas Taylor: Technology. I don't know that was used so much on the C9, but it's still symbolic of the, of the aircraft industry to see the wings tied down. And then that would post it and those pull those top, and that would eliminate a lot of the flutter. So that's sort of how all of that evolved to the shape. So we presented this to Kevin. And Kevin can see through our, our crude modeling and, and accepted this, this concept. Kevin: Mm-hm. Thomas Taylor: Before you. Kevin: And I was thoroughly excited about the possibility of what Thomas and Jeff were proposing here. It kind of validated the idea number one, that the jet wings and the tail section needed to ex, co-exist together in a way that approximated their original relationship. And the second thing was, is that we can still present those relationships in a way that would kind of reconstitute a sense of flight to the aircraft. This is the architectural model our office made in response to Datum's structural design model, and you could begin to see the tie rods existing on the two outside ends of the wings. You can see how two of the three legs of the tripod actually are handled kind of like additional aerofoil sort of struts. But the idea now of it begins to move back in the direction of, what is it's architectural and kind of historical role, being part of the conservation of the park? We're conserving water, we're conserving natural resources, and now we're conserving history. And we're conserving it in a particularly dramatic way, because the jet assembly is located at a position where the parking lot is out in the foreground. And you actually move through and under the jet, as you enter into the park and the trail system beyond. We are adding some motion detectors also for a little bit of drama, but also for conservation. There's no need for electricity or energy to be used when people aren't there. But as people enter and go under the jet, the motion detectors will actually activate the original navigation lights on the jet as a way of making the entire display interactive. And also, perhaps, for it to sort of assume a roll of a kind of centurion. You know, when the jet starts up, and people can detect that it's their motion Doing it they might get the sense that someone's looking after the park, and taking care of it, and making it safe. The concrete plane, as in a architectural plane, kind of materializes in the tail section here as a wall. The concrete wall tapers down and continues and actually forms and follows in a kind of curb-like way, the edge to the accessible path that goes down to the creek water. I mean, you can't have a water conservation project without actually getting down to the creek that the water authority is managing to actually see the water. And so the, the two or three things kind of converged, and the idea of the structural wall kind of tapering down and following that walkway, sort of ends up looking like a contrail. You know? The kind of vapor effect that you see. Thomas Taylor: I see. Kevin: Up in the sky. Thomas Taylor: This is a model taken from RISA. RISA is a structural computer model that we can create structures, by forming specific members that have properties that we can actually measure stresses, deflections, and reactions to a specific structure. And what you see here is dimensionally correct. However, when we show this deflect we've magnified the deflection to, so that we understand the actual movement of it. The wings were actually fairly stiff. I mean, we, we were expecting a lot more flex eh, with the loads that we were putting on there. But they only moved maybe, you know, four inches or so at the very ends. They're fairly long wings, over 60 feet. But four inches is over, over that length is, is something that's a little bit, little bit more than I'd like to see, and that's the reason why we went with the tie-downs. Thomas Taylor: We took our model and put it in Revit, which is our three dimensional modeling software. So we can get oriented, to also explain it to contractors, how this thing will actually work. We also did a good study of the wings themselves, understanding how they work. Which helped us work with the connection of the wing later on. We did some studies on this, and this is the actual wing that we're going to be putting together. And this is the wing route. The right side of that, is where they just took a saw and sawed it right in half. And we're going to have to take that with an opposite side wing, and put it together at that location. This is the wing from the inside, showing all the, the ribs and the stringers. All of this was handmade. I mean you put this thing together, it's not done by a fabricating machine. It's, there's a guy that goes in there and he makes every part that goes on that wing. And see how intricate each piece and part is. This is a hand made machine. Kevin: When the project is completed, there's going to be an open lawn area, there's going to be shade, there's going to be furniture for families to gather around. And then set against all of those prototypes, is this marvelous piece of one off design that is a piece of history, it's a piece of technology. And I think a large kind of effort of creativity, of how to put it all back together in a way that at the end of the day, will be particularly memorable, and certainly delightful.