Flying Tigers

An interview with Charlie Tucker

[In September 1997 I called Charles Tucker at his home and asked him about his experience doing stall tests on the Northrop YB-49 in the summer of 1948. These are my notes of that conversation. Any errors are mine; the ideas and phrasing are copyright 1997 by Mr. Tucker. Anything in brackets is mine. I later met him at an Edwards Air Force Base event and asked him to autograph my book, which he kindly did even after scoffing my notion of a "supersonic stall." (He was quite right, of course.) -- Daniel Ford]

[General Cardenas recalled that he flipped over backwards in the YB-49] "That's bullshit. [Danny Forbes] just saw the ground coming up, and he pulled the wings off. That's what happened.... The plane was completely controllable."

"We went at the thing in what we thought was a safe and sane manner. We didn't know what those [Air Force] guys were doing--there was no chase. They were very secretive about the whole thing from day one. And I had a suspicion--not just me alone--that Russ Schlee and Cardenas and that group from Wright Field were on some kind of a mission to downgrade the airplane, because they wanted the B-36.... They said it was almost unstable and hard to fly. That's baloney. It was solid as a rock. You had some lack of directional damping, not instability, and when we put Little Herbert [autopilot] on it, it was rock solid."

"[The company stall tests] were about a month after the accident. I came in on that program quite late. The two pilots that had flown originally, Fred Bretcher and Max Stanley, they didn't want any part of the stall tests. I said I'd do the stall tests on the airplane. We started out with a forward center of gravity, which is--when you've got a plane with no tail, it's all wing, the only way you could make it stable, at least in those days, is to fly with a pretty forward c.g. The forward c.g. means you have to have the elevons slightly up, or the trim flaps up, and that causes drag. And we started out with a pretty forward c.g., like about 22 percent. It flies just wonderful there. Anybody could fly it. The idea of the airplane being pretty near uncontrollable, I never heard such nonsense in my life. Anyway, we moved the c.g. back further and further, and we did that by shifting fuel, because it had about twelve fuel tanks. Now to do this, and to keep the weight of the plane sensible, we had to come back and land, you know, and put more fuel in, and go up and do it again. So on several days--I don't know, maybe 20, 25 flights there--finally we completed the whole thing. Cardenas suggested that I made only one flight and quit. That's not true either."

"The c.g. was moving back--22, 23, 24--the airplane would become more sensitive to pitch input. In other words, you pull back on the wheel and it was much easier to get the nose to go up. At extreme forward c.g., you could pull back on the stick as hard as you wanted, and the nose would come up 15, 20 degrees and that was as far as you could get it. Then the airplane would fall off on one wing. As you moved the c.g. back further and further, the nose would come higher and higher, and then--it would always fall off on the right wing, I don't know why. I did my damnedest to keep it from doing that, but but it just did; it was just the way the airplane was built, I guess. Always on the right side. Well, finally you get the c.g. back to 27, 28 percent, you pull back on the stick and you get it up to maybe a 30 degree pitch angle, you just let go and the thing would sit there. It didn't do anything; it would just stay there."

[Losing altitude?] "Oh, sure, you were going down like crazy."

"And finally we got the [c.g.] back to the point where I'd just start to move the nose up, and it would start up on its own accord, and I pushed the stick all the way forward and it was still going up. Now you're unstable, see."

[Did you think you were going over backwards?] "Well, who knows? The plane you see has a lot of inertia. It never gave you the idea it was going to do a back flip or anything like that. But the last stall we made--I think we were back to 32 percent--it was ungodly. I had the stick of course full forward, and it just--all I could see was blue sky. I had no idea what the pitch angle was, but it was very high. And it just fell off on the right wing like it did, and 'Hell, that's going to be okay.' I used an airspeed of 140, 150 when I would come out of my wingover, to make my recovery. On the last one--my fault--I always did it very easily, gently, pulling back on the thing--I did a snap. Two and a half turns. Kind of a snap roll. But it recovered quickly. I just gave it left rudder, forward stick, and it came right out. But fortunately I was high enough. Of course it picked up speed like crazy, and I made my recovery, no problem, and that was the end of the stall series."

[How fast?] "Oh, it must have been close to 300. I pulled two and a half [gs]. I was trying to hold it at two gs, because that's what the engineers told me. Anyhow, I did get to 2.5, and it kind of scared me a little bit. But as it turned out, nothing bent or stretched--it was just fine. And after the stall tests were over, I flew the airplane, oh gosh, 90, almost 100 hours, doing autopilot tests. And I enjoyed the hell out of it. I thought it was a wonderful airplane."

[second bomb tests.] "Good ole Russ Schlee! Who knows, maybe they turned the autopilot off when they were doing that. I had a suspicion that that's probably what they did, just to make it look bad. I thought the airplane was great. Now, don't ever get the idea that it was a jet-age airplane. It wasn't. They got this airplane with a 20 percent wing, a big thick wing, and it wasn't built for those high speeds.

[compared to N-9M] "It was such a big machine, it had so much inertia, that those little bobbles were damped right out.

[He lived in La Crescenta, near Glendale] "We'd commute [to Muroc]. We'd stay there maybe a week at a time. We had a barracks, you know, Northrop had a living quarters for the pilots and certain crew members. It was kind of like a beat-up BOQ. It was quite unlike any BOQ you ever saw. It was pretty run-down. Single story. That old base, you know, that was a wreck. We just kind of moved in, everybody, all the contractors just kind of moved in as best they could. "[The YB-49] had bugs. It needed a thinner wing, it needed sweepback, it needed artificial stability."

The High Country

An earlier interview

[Harry Edwards sent me a paper written by two schoolchildren, whose grandfather worked on the YB-49, who'd earlier interviewed Charlie Tucker. This is how they quoted him. -- DF]

"Flying Wing airplanes, old B-49s back in those days, were not efficient enough. In order to achieve stability you had to have a cg that was forward during descent or lift. In order to keep the nose from going down, you had to pull back on the elevator.... If they were up all the time, they would cause excessive drag and loss of lift. I would not say they were more efficient [than conventional aircraft of the time]."

B-35: "The angle of the stress line of the props was cocked up at an angle. Instead of the stress line being symmetrical with the wing, it was cranked up this way. [Fingers up at what the kids thought was a 15 degree angle.] That was a basic flaw that Northrop had throughout his entire B-35 design. I don't know whether [Jack Northrop] was dumb, or he thought that it looked better, but right away he lost thirty percent efficiency on his props by doing that."

"What the Wing needed was: first, more power. Second, a thinner wing. Third, more sweep-back, and fourth, an auto-pilot system so you could fly it neutrally stable. So you wouldn't have all this up-elevator drag, and that is what the B-2 has."

[Karl Nickel said that the deployed elevons on the B-49 and the B-2 both indicated they had aft c.g.! -- DF]

[Instability in yaw:] "The yaw in the B-49 was over-exaggerated. It took a little practice.... I used to take generals for a ride and talk to them and they could fly it pretty good! So there was a certain amount of yaw damping, but when we perfected the auto-pilot on the wingtips ... that stopped it immediately. It was just dead smooth all the time. And yet the Air Force still complained about it. Even though it was a dead deal, so they were schooled to say that, apparently."

[The crash:] "I don't know what the cg was, because if the cg moved further and further aft, the airplane became less and less stable. All we know is that the outer wing panels were broken off in a postive g."

[His stall tests:] "The other two guys didn't want to do it. Max Stanley and Fred Bretcher. They didn't want any part of it. Max had never really stalled the airplane in all the time he'd flown it. He may tell you he did, but he didn't.... It started out with a pretty forward cg--about 23 percent--and it was a big airplane, a lot of inertia, and you pulled back, back, back until you couldn't pull any more, and the airplane would nose up and then the wing would drop off to the right. Then I'd let the thing accelerate to about 140 mph indicated, and then ease back and pull up."

[He wanted the landing gear down; they told him it made no difference.] "As we moved the c.g. back, the stick-force required became less and less. So finally I could get it to the point ... I called it the hold point. I could get it up to a certain angle and let go of the wheel and it would just stay there. Actually, it was at the neutral point where it was getting ready to go unstable. As you moved the c.g. back further, it took almost no force at all to get the nose going up, until finally I got to the stage where I'd pulled it back and then pushed forward all the way and the nose was still going up. With full forward stick! You'd ask yourself, What in the hell would happen next, you know."

"Well, the actual stall, there was no vibration, no shaking whatsoever anywhere on the 172 foot span. But it would always just drop off to the right, just gradually ease down, nose down. In that last stall I did, I was up against the stick, which was pulled [pushed] forward--and the nose going up. And of course I had no idea how high I was. I had a pitch indicator, but it was nothing but blue sky. I couldn't see any land. I didn't know if I was going over the top or what! Finally, it started right wing down, nose down, and then, probably foolishly, I let the thing-- I started my recover at 140, but with that half c.g. I should have known better. And I'd just started to ease back on it, and it snapped on me. Did a two-turn spin. And I ended up actually going straight down."

"So when I pulled the nose up, it went sher-sher and did that. Snap-rolled right into this [spin] so I jammed the stick forward and hit left rudder and it stopped. Of course now I could see the sagebrush practically.... I had a g meter right in front of me because this was only a two g airplane.... So two gs was my limit, but I managed to pull two and a half _g_s, while looking over my shoulder to see what was happened. Everything turned out okay, and that was the end of that. We had gone over 30 percent c.g.--way too far."

"When I went into my tailspin, the engineer had no idea what happened."

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