WESTWICK: So how did you get then from the XST to the Tacit Blue? The path of evolution
goes from XST to Tacit Blue to B-2? Is that correct?
CASHEN: No. It's from Teal Dawn; that's why I'm bringing it up.
CASHEN, JOHN
89
WESTWICK: Teal Dawn, okay, got it.
CASHEN: All right. Teal Dawn was unmanned—it was a cruise missile, a long range, very
large cruise missile. We got the award because we did a very good job on XST. We lost by a
whisker. It was close. And by the way, there's also a frequency issue in this, the bandwidth.
Radars operate over, oh, the best way to describe it is two decades. From basically a hundred
megahertz to 20 gigahertz, okay. So it's more than two decades actually. And how did that stack
up? Because that was a factor too. In the XST competition we were much better in bandwidth.
WESTWICK: So, say, at the extremes of the frequency range?
CASHEN: Yes.
WESTWICK: Both extremes, or just short, or long? Both?
CASHEN: Long.
WESTWICK: You’re better at the long wavelengths.
CASHEN: That's the long suit of this place. We know that end of the spectrum really well.
WESTWICK: Northrop does?
CASHEN: Yes, we do.
WESTWICK: Why is that?
CASHEN: Because we concentrated on it. Because we think it's important, and we concentrate
on it, and we've got a long track record and history of it, starting with XST. But there it didn't
count very much. The evaluation put weight on azimuth angles and frequencies and pitch
angles. It was Damasko’s scoring criteria. It was all geared to the Lockheed design, and we
didn't fit it very well. Where we were good didn't count as much. You see? Where we were bad
had significant credit. But when it was all said and done, we did an incredible job, and we were
close. That's why I think we had no trouble getting Teal Dawn. Teal Dawn we had for about a
year, and then DARPA asked us to spend significant company money, to build an RCS model.
Kent Kresa refused.
WESTWICK: So Kresa has already come to Northrop?
CASHEN: Kresa is now running Ventura. And Ventura division, which was then the
unmanned division of Northrop, made that thing. [pointing to model]
WESTWICK: Which is the…?
CASHEN: The Chukar, the 74.
WESTWICK: BQM-74?
CASHEN: Yeah.
WESTWICK: It's not actually a cruise missile. It's a target.
CASHEN: Yes, it's a target. The reason I brought that—I don't know why—I should have
brought two of them in here. Is that the pointy nose one?
RIVAS: Yes.
CASHEN: Well, there's another one—and I don't know if it's still in the box or not—that's a
rounded nose. The design changed. Now, I'm not sure I know why the design changed, but
pointy noses are good for RCS. I'll leave it at that. I could have sworn I brought the other one.
WESTWICK: Here's one.
CASHEN: Yeah, here it is. This thing was produced forever and always. See the differences?
Now, you can argue the differences are for aerodynamic performance. But trust me, the frontal
radar cross section is a hell of a lot better just due to the shape changes.
CASHEN: All right. And see that, Maggy?
RIVAS: Upside down, huh?
CASHEN: No. Look at this; now, look at this. This is the Chukar that was made for decades.
Look at the wing sweep. Look at the nose shape. Anyway, I leave it at that. They went into
production on all of this after I retired, but I can tell you that I wouldn't have argued with it.
WESTWICK: So Kresa comes over from…
CASHEN: Kresa was at DARPA.
WESTWICK: Yeah. Had he been involved with the XST?
CASHEN: Well, the short answer is yes and no. He was involved in the setting up of that telex.
But before the contracts were ever awarded, he joined Northrop to run our research lab. He
consulted with us on our XST activity and our bid.
WESTWICK: Did you get any inside scoop from him on what DARPA was looking for?
CASHEN: No more than we already knew from Perko. I mean, he confirmed everything that
Perko said. It was pretty simple. You know, what we were talking about. He didn't know about
Nick Damasko or any of that. He tried to help us in every way possible while he ran our
research lab. After that he took over the Ventura division, and he was running the Ventura
division at the time of Teal Dawn. He also started a program called Tacit Rainbow, which was
kind of his pet project. It got quite far along before it got canceled, but that's another story. It's
not stealthy. There are plenty of people to tell you about Rainbow. I can tell you some about it,
but it's not on this table.
Anyway, Teal Dawn made us step back and think about what we'd done on XST and
create for the very first time a wing-body-tail all-aspect design. What it was based on was the
original Mark 12, the Minuteman reentry vehicle, the ice cream cone, had been studied by the
Siegel group at Michigan to the extent that they were convinced it was the ideal radar cross
section shape for the reentry application, that you could never do any better than the ice cream
cone. It was ideal. And I think it's been proven that way over the decades since then. So, what is
the ideal airplane? The ice cream cone's axially symmetric. An airplane can't be axially
symmetric. An airplane's got to have wings. That by definition makes it planar. Maybe it's a
flat plate, an infinitely thin flat plate. That would be the ideal radar cross section shape for an
airplane. You can't make an airplane infinitely thin because you have to put a person and
engines in it. So what you do is start out with a flat plate, and you grow above and below that
plate the volume necessary to make it into a functional system, and minimize as much as
possible the increased RCS due to the addition. But you start out with a flat plate.
WESTWICK: Does it have to be round?
CASHEN: Well, I didn't say that. I just said a flat plate. Now, there are other rules that say that
it should not be round; it should in fact be straight-edged. It turns out the fewer the edges the
better. But more importantly, the alignment of the edges is important. If you've got multiple
edges, you do everything to align them.
WESTWICK: You mean where they meet?
CASHEN: Aligned edges—a set of parallelograms.
WESTWICK: I got it.
CASHEN: They're aligned. Parallel. Parallel planforming we call it. Now, it turns out the
design of an airplane historically starts out with a plan view, whether a designer hand draws it or
does it on a computer. He starts out with a plan view, and then he starts to grow the third
dimension. So the idea of RCS design, Stealth design, of an airplane that starts out with a plan
view is consistent with the existing airplane design process. That's the process here at Northrop.
It always has been, always will be. Lay out a plan form that you want, because your RCS pattern
in azimuth is dominated by the plan form that you've created. And then change it as necessary in
creating the real airplane. It's done that way with Tacit Blue—they're all that way. So, we
learned that on Teal Dawn, a wing-body-tail cruise missile, and we created our Teal Dawn
accordingly.
We also learned to use MOE-based system analysis.
WESTWICK: Measure of effectiveness
"SENIOR" Class programs (USAF Headquarters/Pentagon NRO codenames)