A B-1B Lancer aircraft takes off from Ellsworth Air Force Base, S.D., Aug. 3, 2010, for a training mission. (DoD photo by Airman 1st Class Corey Hook, U.S. Air Force/Released)
Thanks for posting this. It brings back fond memories. I worked for North American in the sixties on both the XB-70 and the B1 program. As a senior tech I remember recording the dynamic data on one of the first B1 models that we subjected to very high speed wind tunnel tests at the NA facility on Imperial Blvd on the S side of LAX. It was a boring project for me because it took several hours to refill the huge air tanks with compressed air for the short few minutes when I actually recorded the data as the air rushed past the model. So I read a lot as I sat at my console.
Hi Eddie, OK. I'm guessing 1967 but it could be 1968. The lab I worked in (Structural Dynamics) mostly used Ampex 14 track FM tape recorders. FM because we often needed to record DC as well as AC signal levels. But now that I think about it I bet I used moving pen strip chart recorders on this test or maybe those light beam / mirror deflection paper recorders because I remember the engineers wanted a fast turn around. The taped data would have required time for analysis in the lab.
They'd examine the data after the run and make some changes on the model using some kind of molding clay. This would take a while and then we'd run again as soon as those air tanks were filled. There was like 8 or 10 tanks and each one was about 16 or 20 feet in diameter as I recall sitting just outside the tunnel facility. I remember we had analog signal conditioners / amplifiers that required zero offset and amplitude calibration before each run. I think we were using mostly differential (4 leg) strain gauges on this test. No computers at all. I don't think I'm violating what was called my "Top Secret" clearance that I held at the time by telling you any of this. ;-)
Let me add that my memory is hazy on this because my lab when some project needed structural data analysis we were sent out on that job. I spent about 6 months in Houston for example working on the Apollo program where we literally shook full size models of the rocket stages with huge speaker coils and amps to find resonances. Then maybe I'd get sent to Edwards to work on an F-100 gun test or something. I did work at Edwards for a year or so on the XB-70 program collecting vibration and acoustic skin pressure data.
Ray, WOW! Pretty cool. You were there during the space program. You must be very disappointed with the way the space program has languished since the moon landings. Once the US won the race to land a man on the moon, things changed. There is an Apollo Guidance Computer simulator project
About how long did it take to fill those tanks, and about how long would the wind tunnel test run - how long a test could they perform until the tanks emptied?
Last first: Hazy memory but the tanks needed 4 to 6 hours I think. My memory is telling me the test lasted only a couple of minutes as the airflow was several multiples of the speed of sound in air (mach number).
About being disappointed: I am not. I accept that in a liberal democracy what the majority want is the reality we must live with. Rather than complain I prefer to make the best of it and see what other possibilities come up.
It was fulfilling for me and exciting at times . . but by 30 years old I discovered I was not so well suited to being an employee in a large company and went on to starting several of my own small companies . . following whatever interested me at the time and was within my financial reach. I certainly have not become wealthy by today's standards but I get by and have had a wonderful time along the way.
That photo makes a great background on my monitor BTW.
Added: As I think about it one reason it took so long for the tanks to fill was that compressing the air created a lot of heat in the tanks that had to dissipate to get the required volume of air available at the pressure the pumps were capable of. I think someone told me the tanks had empty aluminum cans in them to help dissipate that heat. That air made quite a roar when they dumped it through the throat of the tunnel where the model was mounted.
That photo makes a great background on my monitor BTW.
Indeed. Muted solid colors, simple textures and low-key pictures work a lot better ergonomically than a busy image with detailed, distracting elements. Almost all of the snapshots and photos Nappy's seen people use for their backgrounds are textbook examples of bad choices for the purpose. Nappy likes to keep it boring, so the foreground, the icons and text, are what draw the eye.
Yeah! And that high color temp exhaust really pops out against the clouds illuminated by a blue-absorbing low sun angle. You must do web design. If not, maybe you should ;-)
Nope. Just an abiding interest in design, including graphic design, layout and interfaces.
When the Unix industry adopted the X Window system, in an attempt to derail Sun's far superior NeWS (Network extensible Window System), a lot of horrid GUI applications came crawling out of the woodwork. Like cockroaches. Rather than go for Xrn or another of its awful ilk of slapdash GUI front-ends for rn or trn. Nappy continued using NN because it was well designed with a clean interface. Can't beat the tag-line: No news is good news.
Enough old war stories. Time for a nap.
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Thanks for posting this. It brings back fond memories. I worked for North American in the sixties on both the XB-70 and the B1 program. As a senior tech I remember recording the dynamic data on one of the first B1 models that we subjected to very high speed wind tunnel tests at the NA facility on Imperial Blvd on the S side of LAX. It was a boring project for me because it took several hours to refill the huge air tanks with compressed air for the short few minutes when I actually recorded the data as the air rushed past the model. So I read a lot as I sat at my console.
Can you be more specific on the year? How was the data logged? Charts/Plotters? Computers?
Did you need a Security Clearance? I'm guessing you did.
Hi Eddie, OK. I'm guessing 1967 but it could be 1968. The lab I worked in (Structural Dynamics) mostly used Ampex 14 track FM tape recorders. FM because we often needed to record DC as well as AC signal levels. But now that I think about it I bet I used moving pen strip chart recorders on this test or maybe those light beam / mirror deflection paper recorders because I remember the engineers wanted a fast turn around. The taped data would have required time for analysis in the lab.
They'd examine the data after the run and make some changes on the model using some kind of molding clay. This would take a while and then we'd run again as soon as those air tanks were filled. There was like 8 or 10 tanks and each one was about 16 or 20 feet in diameter as I recall sitting just outside the tunnel facility. I remember we had analog signal conditioners / amplifiers that required zero offset and amplitude calibration before each run. I think we were using mostly differential (4 leg) strain gauges on this test. No computers at all. I don't think I'm violating what was called my "Top Secret" clearance that I held at the time by telling you any of this. ;-)
Let me add that my memory is hazy on this because my lab when some project needed structural data analysis we were sent out on that job. I spent about 6 months in Houston for example working on the Apollo program where we literally shook full size models of the rocket stages with huge speaker coils and amps to find resonances. Then maybe I'd get sent to Edwards to work on an F-100 gun test or something. I did work at Edwards for a year or so on the XB-70 program collecting vibration and acoustic skin pressure data.
Ray, WOW! Pretty cool. You were there during the space program. You must be very disappointed with the way the space program has languished since the moon landings. Once the US won the race to land a man on the moon, things changed. There is an Apollo Guidance Computer simulator project
About how long did it take to fill those tanks, and about how long would the wind tunnel test run - how long a test could they perform until the tanks emptied?
Last first: Hazy memory but the tanks needed 4 to 6 hours I think. My memory is telling me the test lasted only a couple of minutes as the airflow was several multiples of the speed of sound in air (mach number).
About being disappointed: I am not. I accept that in a liberal democracy what the majority want is the reality we must live with. Rather than complain I prefer to make the best of it and see what other possibilities come up.
It was fulfilling for me and exciting at times . . but by 30 years old I discovered I was not so well suited to being an employee in a large company and went on to starting several of my own small companies . . following whatever interested me at the time and was within my financial reach. I certainly have not become wealthy by today's standards but I get by and have had a wonderful time along the way.
That photo makes a great background on my monitor BTW.
Added: As I think about it one reason it took so long for the tanks to fill was that compressing the air created a lot of heat in the tanks that had to dissipate to get the required volume of air available at the pressure the pumps were capable of. I think someone told me the tanks had empty aluminum cans in them to help dissipate that heat. That air made quite a roar when they dumped it through the throat of the tunnel where the model was mounted.
Yeah! And that high color temp exhaust really pops out against the clouds illuminated by a blue-absorbing low sun angle. You must do web design. If not, maybe you should ;-)
Nope. Just an abiding interest in design, including graphic design, layout and interfaces.
When the Unix industry adopted the X Window system, in an attempt to derail Sun's far superior NeWS (Network extensible Window System), a lot of horrid GUI applications came crawling out of the woodwork. Like cockroaches. Rather than go for Xrn or another of its awful ilk of slapdash GUI front-ends for rn or trn. Nappy continued using NN because it was well designed with a clean interface. Can't beat the tag-line: No news is good news.
Enough old war stories. Time for a nap.