And what country can preserve its liberties if their rulers are not warned from time to time that their people preserve the spirit of resistance? Let them take arms. The remedy is to set them right as to facts, pardon and pacify them. What signify a few lives lost in a century or two? The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants.
Thursday, April 22, 2021
North American XB-70 Valkyrie experiencing skin separation during flight
I hate to throw a wet towel on the party -- well, not really. It's where the paint burned or peeled off during flight. After all, Valkyrie didn't just lollygag around when she was flying. That plane really moved.
The XB-70 fuselage was made of stainless steel face sheet honeycomb with stainless steel core that was brazed in place in an autoclave. It was a very innovative material at the time but paint adhesion was an issue especially when punching through mach 1. If you ever gat a chance to look at the surviving example in the Wright Patterson Air Force Museum in Dayton you should definitely do it.
The B57 Hustler suffered the same problems with paint adhesion. The ground crews could tell how fast the plane had gone in the last flight by how much paint was burned off.
I got the chance to see that thing fly and crawl around it a few times as a kid at Edwards in the mid 60’s. It’s massive. When I worked F-4’s we could tell they were scooting by the peeled paint on the engine intake and wing leading edges. Didn’t have that issue once I got wrenching on Warthogs.
in the days before epoxy/polyester paints, this is what happens when the skin thermally expands faster then the paint thermally expands. paint loses adhesion with the metal and just pops off the skin. heat was generated by Mach speeds approaching SR-71 territory. Concord had epoxy type paint and didn't suffer this indignity. My E-3 had what is known as "flash paint" which when exposed to a pulse of IR such as from a nuclear detonation, foams up to form a thermal barrier to protect the structures beneath. most high performance aircraft-military- are covered with some form of epoxy paint, though not to make it pretty, but to protect alloys from corrosion, and matte finished to eliminate glint. airliners, not so much. Oh, you can do a lot of different things with paint. X-15 had ablative paint designed to flake away the heat it absorbed. the one XB-70 that NASA and North American Aviation didn't manage to destroy is housed at The Museum of the United States Air Force at dayton ohio(free admission). for those that lust after the sight of large exhaust pipes, that would make the trip worthwhile. it has six of them.
Hey, Rockwell. Because you did such a great job on the skin of the XB-70, how'd you like the same job for the Lunar Module?
ReplyDeleteYes, yes, I know it was NA. But it was North American Rockwell on the LM. Rockwell for short.
DeleteLEM was Grumman.
DeleteI hate to throw a wet towel on the party -- well, not really. It's where the paint burned or peeled off during flight. After all, Valkyrie didn't just lollygag around when she was flying. That plane really moved.
ReplyDeleteThe XB-70 fuselage was made of stainless steel face sheet honeycomb with stainless steel core that was brazed in place in an autoclave. It was a very innovative material at the time but paint adhesion was an issue especially when punching through mach 1. If you ever gat a chance to look at the surviving example in the Wright Patterson Air Force Museum in Dayton you should definitely do it.
ReplyDeleteThe B57 Hustler suffered the same problems with paint adhesion. The ground crews could tell how fast the plane had gone in the last flight by how much paint was burned off.
ReplyDeleteB-58 Hustler. B-57 was the Canberra. Very, very different birds. I doubt the 57 would go fast enough to even get the paint warm.
DeleteI got the chance to see that thing fly and crawl around it a few times as a kid at Edwards in the mid 60’s. It’s massive. When I worked F-4’s we could tell they were scooting by the peeled paint on the engine intake and wing leading edges. Didn’t have that issue once I got wrenching on Warthogs.
ReplyDeletein the days before epoxy/polyester paints, this is what happens when the skin thermally expands faster then the paint thermally expands. paint loses adhesion with the metal and just pops off the skin. heat was generated by Mach speeds approaching SR-71 territory.
ReplyDeleteConcord had epoxy type paint and didn't suffer this indignity. My E-3 had what is known as "flash paint" which when exposed to a pulse of IR such as from a nuclear detonation, foams up to form a thermal barrier to protect the structures beneath. most high performance aircraft-military- are covered with some form of epoxy paint, though not to make it pretty, but to protect alloys from corrosion, and matte finished to eliminate glint. airliners, not so much. Oh, you can do a lot of different things with paint. X-15 had ablative paint designed to flake away the heat it absorbed.
the one XB-70 that NASA and North American Aviation didn't manage to destroy is housed at The Museum of the United States Air Force at dayton ohio(free admission). for those that lust after the sight of large exhaust pipes, that would make the trip worthwhile. it has six of them.