"Rock Bottom" (rockbottom81)
10/04/2013 at 06:30 Filed to: Planelopnik
8
65|
"Rock Bottom" (rockbottom81)
10/04/2013 at 06:30 Filed to: Planelopnik | 8
| 65 |
I love wind tunnels, aircraft, and history. If you do too, check this out and use your Google-fu to search for some more info on these cool machines and tests. My goal here is to spread the word that we, as a culture, have made some amazing advances in aeronautics over the years and, if we try, we can still keep doing awesome science experiments to push the envelope further!
History: In 1944 the National Advisory Committee for Aeronautics (NACA, later to become NASA) commissioned the 40x80 Wind Tunnel at Moffett Field, California. She was designed and built in only a few years, with her first test taking place in August of 1944. Shes still here today, a testament to the solid engineering of her creators and the intelligent upgrades and careful maintenance of subsequent generations of engineers, technicians, electricians, and mechanics.
She has been modified several times over the last seven decades, including a major mod in the early 1980s that added a second test section, the 80x120, and nearly 100,000 additional horsepower. You read that right. When the 40x80 was born in 1944 she was blessed with six fans, each with 6,000 horsepower. She now has six much angrier fans, each with 22,500 horsepower. Thats 105 megawatts worth of Al Gores tears. When this second monstrous test section was added, the tunnels were renamed the National Fullscale Aerodynamics Complex (NFAC). The two tunnels ran up until NASA mothballed them in 2002. Congress recognized this machine as a national asset and asked the US Air Force to re-activate them in 2004. Weve been running like crazy ever since!
I feel its important to mention this: due to security under the direction of the USAF, we cant release nearly as many pictures of our most recent tests as we would like. Some, like the MSL Parachute pictures down at the bottom, have been released to the public. Keep your eye to the interwebs! As test data is cleared for public consumption, well be getting it out!
Since were all gearheads here, Ill drop some stats:
Total Horsepower: 135,000 hp
Total Electrical Draw: 105 MW
Fan Drive Mass Flow Rate: 60 tons/second
Speed: 300 knots in 40x80, 100 knots in 80x120
The Fan Drive : Heres a couple pics of the fans. The first one is in 1944, the second is in 1986. Note the people standing by the center bottom fan in the second pic.
Now, heres a few of my favorite test pictures and a little info on each one.
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1944: Douglas BTD-1 Destroyer - The first 40x80 test was conducted at the height of WW2. An advanced replacement for the Douglas Dauntless and Curtiss Helldiver was needed. This was it.
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1945: Douglas A-26 Invader - There were many modifications to the airframe, aerodynamics, and load-out for the venerable Invader over the years.
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1951: F-86 Saber - Early refinements to everyones favorite Korean War fighter jet!
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1960: Avrocar - Bizarre flying-saucer VTOL thing icky.
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1962: Super Sonic Transport (SST) - One of literally dozens of SST concepts tested in the 40x80 over the years.
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1963: NASA M2-F1 Lifting Body - This little guy was born here at NASA Ames, tested, then finished up and flown down at Edwards. Knowledge gained from these lifting-body tests (along with the X-15 and Dyna-Soar) gave NASA the tools to build the Space Shuttle.
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1964: Bell Helicopter Rotor System Test - This was one of the earlier helicopter tests performed in the 40x80. As you can gather from the fact that there is only a rotor, no fuselage, this is a test to study the rotor only. Tests like this allow us to understand how the rotor really works (which is an art in itself). We humans are still learning about rotors, which is why rotor tests are the bread-and-butter of the NFAC to this day. That, and there is no other place in the world where you can test a usefully-sized rotor
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1964: Ryan XV-5A Vertifan - This was one of the early XV test aircraft developed here at NASA Ames to test vertical takeoff and landing (VTOL) technology.
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1966: Bell Helicopter High-Speed Rotor - This is another rotor test in the 40x80. Fun fact: the tellow test rig in the picture is still in our inventory today. Its a good little rig. We call it The Easter Egg.
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1966: Double-Delta Planform SST - Another SST test. This guy actually came and went several times in the 1960s.
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1966: Bell XV-3 - One of my favorite flying machines of all time. It was the grand-daddy of the V-22 Osprey and the first truly successful tilt-rotor aircraft. The wings ripped themselves off after this picture and it made a mess of the place. But the nice folks at the Air Force museum in Ohio fixed it up and put it on display a few years ago, so go see it. It rocks.
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1966: Lockheed Stopped Rotor Compound Helicopter - This was a concept that was toyed with back in the day. The thought was that if you had wings and a jet engine, you could stop the rotor in flight and fold it up to reduce drag. Basically, its an airplane that can deploy a rotor to land and takeoff.
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1968: Hughes OH-6 Loach - As I understand, this was a fairly standard drag clean-up test. But it sure looks cool!
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1968: Lear-Jet - Aerodynamic testing of an early Lear-jet test article. Reason: unknown!
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1969: Hunting H.126 (British) - One of the earlier experiments using blown flaps where you blow high-pressure air over the wing flaps (usually) to energize the boundary layer and augment their effectiveness. Its a solid idea and we continue to refine the technology today.
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1969: Supersonic Commercial Air Transport (SCAT) - yet another SST
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1970: Sikorsky Advancing Blade Concept (ABC) - This was a pretty cool coaxial helicopter concept from Sikorsky. The hub was very rigid and I dont think the blades were articulated, as they are on pretty much everything this side of a BO-105. This concept would come back to the 40x80 ten years later for more testing and would also fly as the Sikorsky S-69.
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1972: Boeing Tilt-Rotor Semi-span Test - In the early 70s there were several companies vying for government tilt-rotor aircraft contracts. This was in support of one of Boeings concepts.
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1974: Boeing 747 Wake Vortex Survey - You know how you have to wait a while after a plane takes off before another is allowed onto the runway? Its because airplanes really screw up the air. Especially heavy ones. Tests like this one show us how much spacing is needed between planes. As you can guess, you need a pretty big wind tunnel to do this in.
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1975: Space Shuttle Orbiter 101 Test - There were several space shuttle configurations tested here. This one was called the 101 test and was pretty close to the final configuration.
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1978 Bell XV-15 Check-out Test - This was the second generation tilt-rotor, after the Bell XV-3 and before the V-22 Osprey. Before the XV-15 was allowed to really get into the meat of its flight test program, it was flown in the 40x80. Good thing! They discovered that the tail wasnt stiff enough for high-speed flight and fixed it before a pilot found out the hard way.
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1980: Sikorsky ABC Test (second entry after the 1970 test) - This is the second time the Sikorsky ABC came to the 40x80. This was in support of the flight test program.
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1988: Heavy Vehicle Drag Reduction (Phase 1) - This was the first of several semi truck tests to go into the 80x120. The most recent was in 2010. Notice all those new fairings under truck trailers lately? Also, yes. This is a real truck, not a scale model. The tunnel really is that big.
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1991: F-18 High-Alpha Engine Intake Flow Study - In the late 80s the Blue Angels discovered that if you hooned an F-18 too hard, the engines stalled. They flew one here, plopped it in the 80x120, and discovered that the inlets needed redesign. Now you can hoon an F-18 much harder.
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1993: High-lift Engine Aeroacoustics Technology (HEAT) semi-span test - Semi-span test (half an airplane) to study the acoustic signature of things like lift augmenting devices on a SST.
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1994: High Speed Civil Transport (HSCT) - Another (yawn) SST
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2000: National Renewable Energy Laboratory (NREL) Scale Wind Turbine - The steady, controlled conditions in the 80x120 allow for precise measurements of the flow through and around wind turbines, leading to improvement of the technology and turbine placement. Expect to see many more of these types of tests in the near future.
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2000: Tilt Rotor Acoustic Model (TRAM) - This is a Ό scale V-22 model, designed to acquire acoustic data of a tilt-rotor aircraft in flight.
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2001: Large Rotor Test Apparatus (LRTA) UH-60 Individual Blade Control (IBC) - I describe the LRTA as 75,000 lbs of angry helicopter test machinery. This machine is the only practical way to drive a chopper main rotor into the stall region. This particular test was part of a series of entries to study the feasibility of some advanced helicopter control system hardware.
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2009: Mars Science Laboratory (MSL) Main Parachute Test - Many of you have heard of the Curiosity Rover that we dumped on Mars last year. This parachute is how it was slowed enough to use the Skycrane. The parachute deployed in the Martian atmosphere at around Mach 2 and worked like a charm. Wind tunnel testing allowed for the parachute design to be refined and perfected before sending it to Mars.
Racescort666
> Rock Bottom
10/04/2013 at 12:23 |
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Double post. My bad.
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Racescort666
> Rock Bottom
10/04/2013 at 12:23 |
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Great read Jon. It drives me crazy when people think that the only thing that NASA does is launch space shuttles and this shows just a little glimpse of some of the other awesome things you guys do.
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Rock Bottom
> Racescort666
10/04/2013 at 12:56 |
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And this facility (which is currently run by the USAF) is just a tiny corner of the scientific world we live in! The DoD, DARPA, the Department of Energy, and NASA (when properly funded) push metallurgy, composites, and advanced construction techniques to the next level. This is good for car guys. They also do a ton of biology research. That's good for anyone who wants to live longer.
Icemanmaybeirunoutofthetalents
> Rock Bottom
10/04/2013 at 17:36 |
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Aerospace, engineering porn overload!
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Rock Bottom
> Icemanmaybeirunoutofthetalents
10/04/2013 at 17:37 |
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I know, right!
Mikeado
> Rock Bottom
10/04/2013 at 18:35 |
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I thought this was Thunderbird 4 for a second!
Cabe N. Allen
> Rock Bottom
10/05/2013 at 08:51 |
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Fantastic article. I am very intrigued by the "flying saucer" photo. An Area 51 find or testing ideas from Gene Roddenberry? LOL
Bluecold
> Rock Bottom
10/05/2013 at 09:01 |
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Another cool picture of the NREL test. This was done with a smoke grenade attached to a blade. These full scale tests were very important for wind turbine wake understanding.
Also, protip if you want to sound smart when talking aerodynamics, NACA is pronounced in the individual letters. Not 'naka'.
majorbloodnok
> Rock Bottom
10/05/2013 at 09:25 |
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Absolutely fantastic, thank you for sharing!
Busslayer
> Rock Bottom
10/05/2013 at 09:57 |
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Cool stuff. Are some of these tests done for paying customers (Bell) .
jalop1991
> Rock Bottom
10/05/2013 at 10:02 |
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Thats 105 megawatts worth of Al Gores tears.
I hoon, therefore I am
> Rock Bottom
10/05/2013 at 10:04 |
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That looks like a Lear 35, which replaced the GE turbo jets found on earlier Lears with much more efficient TFE731-2 turbofans from Garrett. This basically launched Garrett (now Honeywell) into the business/general aviation behemoth that we all know and love today.
The Tacit Blue wouldn't happen to have been tested there, was it? That thing was a feat of aerospace engineering, and easily the most unstable aircraft man had built to that point. The program was instrumental in developing our stealth capabilities.
472CID
> Rock Bottom
10/05/2013 at 11:01 |
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So the government was just trolling us the entire time.
ElJefe5ohGT
> Rock Bottom
10/05/2013 at 11:04 |
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The Fan Drive
: Heres a couple pics of the fans. The first one is in 1944, the second is in 1986. Note the people standing by the center bottom fan in the second pic.
It's kind of funny that you guys took the same route that shaving razors took. More blades is better!
Dake
> Rock Bottom
10/05/2013 at 11:17 |
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Fantastic article and pics.
On a side note, I didn't think there were many experimental aircraft I wasn't at least aware of, yet I somehow missed the Ryan XV-5A Vertifan . Fascinating little plane and the flight test videos are interesting. From the angle in the picture it looks like a mini Aliens dropship. Love it.
matt88me
> Rock Bottom
10/05/2013 at 11:29 |
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The lifting body looks like the craft Steve Austin was in before it crashed in the opening sequence of the 6 Million Dollar Man.
How much do you think Steve Austin would cost now in our current current market...... LOL
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matt88me
> Rock Bottom
10/05/2013 at 11:29 |
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The lifting body looks like the craft Steve Austin was in before it crashed in the opening sequence of the 6 Million Dollar Man.
How much do you think Steve Austin would cost now in our current current market...... LOL
the7thearlofgrey
> Rock Bottom
10/05/2013 at 11:54 |
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what a waste of taxpayers money when they could of just used Storm " she likes blowing stuff"
Jeffrey Lo
> Rock Bottom
10/05/2013 at 11:55 |
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Very cool stuff. I got a tour of the facility in the late 70's when I was a kid. Great to see it has gotten upgraded. Now, I just wish I could get my race plane in there to figure out why it wants to depart in yaw at 285mph...
JayHova
> jalop1991
10/05/2013 at 12:03 |
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Unfortunately this isn't quite right. It's an all electrical system. #1 is the stuff that makes Al Gore cry . It actually would increase the awesome even more, because 'turbocharged wind-tunnel'.
!!! UNKNOWN CONTENT TYPE !!!
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Rock Bottom
> I hoon, therefore I am
10/05/2013 at 12:27 |
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There are several "blacked out" parts of the old test log, so I guess it's possible Tacit Blue came here at one time. I will say that due to the amount of attention NFAC tests generate (people notice trailers with exotic planes rolling into Ames) we don't get a lot of secret stuff. Lots of proprietary tests come through here.
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Rock Bottom
> Bluecold
10/05/2013 at 12:30 |
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Thanks for the photo! I had the video, but couldn't get it to screen-cap cleanly.
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Rock Bottom
> Jeffrey Lo
10/05/2013 at 12:36 |
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I would have loved to see this place before and after the upgrade! When I started, there were still some engineers floating around who had tested here in the old days. They had some great stories and great wisdom.
Also, we have an opening in the schedule in late 2018. Shall we pencil you in? Ha ha!
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Rock Bottom
> Busslayer
10/05/2013 at 12:41 |
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Yes, we do have commercial customers as well as government organizations. It's most common for a government agency like NASA or the USAF to "sponsor" a corporate test that interests them. That way, the company and the government share costs and both get valuable data.
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Rock Bottom
> Dake
10/05/2013 at 12:47 |
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Don't feel bad. The whole XV series is pretty obscure. VTOL isn't nearly as flashy as breaking speed records!
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Rock Bottom
> ElJefe5ohGT
10/05/2013 at 12:51 |
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Those blades are pretty awesome on their own. They each weigh about 900 lbs and are made of friggin' wood! I love when you can reach into the past for a solution to a modern problem.
tromoly
> Rock Bottom
10/05/2013 at 13:02 |
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Do they have the 40x80 and 80x100 test sections on the same loop?
Also, just 'cause I'm curious, is there capability for a rolling road to be set-up for automotive testing? I couldn't quite tell from the picture with the semi-trailer.
Thank you for sharing, to a person studying fluid dynamics this is as close to wind tunnel pornography as can be had.
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Rock Bottom
> matt88me
10/05/2013 at 13:06 |
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Good eye! This aircraft developed into the M2-F2, which was used in the footage on the show. They used footage from the actual crash that ended that plane, too! It wasn't just a Hollywood stunt!
Evan, Pope Of Jalopnik by Self-Appointment
> Rock Bottom
10/05/2013 at 13:12 |
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Wow almost as much power as my car makes!
But seriously. Awesome article, and unbelievable pictures. Thank you so much.
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Rock Bottom
> tromoly
10/05/2013 at 13:18 |
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The test sections share a drive, but are not in the same loop. The 40x80 is a standard single-return tunnel, while the 80x120 is a non-return. The air gets sucked into the inlet from outside, through the test section, through the fans, and is exhausted outside. We have a series of HUGE vane sets that divert the air to either test section. If you look at the tunnel from Google Earth you can see the rectangular 40x80 circuit with the 80x120 (and it's huge bell mouth inlet) sticking off at about 45° to the North West.
I wish we had a rolling road, but one big enough for a semi would be insanely expensive. And awesome. You never know, we might build one some day, but we really don't do many automotive-style tests. Less than half a dozen in the past couple decades. Those will usually go places like the Wind Shear tunnel in SC, which I believe has the world's fastest rolling road.
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Mark Out West
> Rock Bottom
10/05/2013 at 13:22 |
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Hell, if it wasn't for you guys the U.S. wouldn't have a tiltrotor program. A lot of folks are certainly aware of the V-22, but the NASA/Bell XV-15 really proved the technology and did so with reasonably low costs. I was there when an XV-15 landed on the U.S. Capitol steps. Wowed the hell outta everybody. Result: V-22 didn't get chopped by Cheney.
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tromoly
> Rock Bottom
10/05/2013 at 13:31 |
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I see it now, that mouth is HUGE!!
From a picture I found online (shown below), are there several other smaller wind tunnels on site? Namely the lower-left corner, lower-right corner, and right-hand-side in the foreground of the big tunnel, with a couple more visible in Google Maps.
Makist
> Rock Bottom
10/05/2013 at 13:32 |
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When I saw the picture up top, my first thought was "Storage rack for 'Fatman'-style atom bombs".
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Racescort666
> Rock Bottom
10/05/2013 at 13:34 |
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This is speaking from expereince: most of the wind tunnel testing that's done in the auto industry is done on a chassis dyno built into the test section. Mostly it's used for hot room testing where the cooling pack is validated at different ram air speeds at max power. Ram air is usually low speed and ambient temp is usually pretty high to make sure you don't overheat the vehicle.
The hard part about doing a rolling road, or even an all wheel chassis dyno is that cars walk all over the place when they're moving.
Edit: on the plus side, the test section is so big that you could just have a rolling road or chassis dyno on casters and roll it onto the floor and roll it off. Most of them are big steel structures anyway and fairly easy to make them mobile.
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Rock Bottom
> Evan, Pope Of Jalopnik by Self-Appointment
10/05/2013 at 13:36 |
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Thank you for the kind words. I'm super proud and fortunate to be here and I take every opportunity to show it all off!
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Evan, Pope Of Jalopnik by Self-Appointment
> Rock Bottom
10/05/2013 at 13:43 |
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Haha no problem! Keep up the good work!
frankfan42x
> Rock Bottom
10/05/2013 at 13:44 |
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Very cool stuff. Anybody know why they decommissioned it the first time? Was it due to the belief that computer sims would carry the day? There is likely more to this as that does not sound right. Do we have an even larger and more advanced wind tunnel that is classified?
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Rock Bottom
> tromoly
10/05/2013 at 13:48 |
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This is an old pic, things have changed quite a bit! Bottom left is the old 12 foot pressure tunnel. It was torn down to the foundation and rebuilt in the 90s and is now, sadly, mothballed. It hasn't run in years. Bottom right are the twin 7x10 tunnels. One was demolished a couple years ago and the Army runs the other one today. Between the 7x10s and NFAC is the old 14ft transonic tunnel. It was demolished about 5 years ago. It's now a park. Just out of sight to the right is the NASA Ames Unitary Plan Tunnel (not to confused with the Langley tunnel of the same name), which has 3 test sections and is touted as the most productive tunnel in the world. The are ALWAYS blowing air! They have an 11 ft transonic section, 9x7 supersonic, and an 8x7 Mach 3.5 section. The 8x7 was mothballed in the 90s but might come back...
wagnerrp
> frankfan42x
10/05/2013 at 13:50 |
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Even us computer sim people don't believe computer sims will replace physical tests in the near future. We often use physical tests of the same model as validation for our simulations.
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wagnerrp
> Rock Bottom
10/05/2013 at 13:51 |
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The S upersonic C ommercial A ir T ransport? Seriously, people need to be more cautious of their acronyms....
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Rock Bottom
> frankfan42x
10/05/2013 at 13:59 |
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She was mothballed because of funding shortages. This is a great example of what you lose when you cut the country's science budget! Luckily, she wasn't too far gone to resurrect. We all know that machines hate to sit idle. It's really hard on them.
As for computers, well, they've been telling us "don't get too attached to your wind tunnels" since the 1960s and we're still here! Computers can predict things, but I'm unimpressed. Maybe in 20 or 30 years...
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Rock Bottom
> wagnerrp
10/05/2013 at 14:05 |
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We have fun with acronyms some times. Roving Acoustic Test System (RATS) and Cost-effective High Efficiency Acoustic Project (CHEAP) are a couple examples of what happens when NASA engineers get bored.
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tromoly
> Rock Bottom
10/05/2013 at 14:12 |
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That is quite a history lesson. Thank you for taking the time to explain these things, it is very interesting to hear the history behind such important facilities.
'olJackBurtonAlwaysSays
> Rock Bottom
10/05/2013 at 14:22 |
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obligatory.
Thanks, great post.
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Icemanmaybeirunoutofthetalents
> Rock Bottom
10/05/2013 at 14:43 |
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Does the facility have its own reactor/power plant to power it? That thing gets really hungry!
onerunjunior
> Rock Bottom
10/05/2013 at 15:22 |
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On the picture of the Mars Rover parachute I remember they tested that chute incorrectly. They tested it at deployment speed and it kept failing spectacularly but then remembered that the Martian atmosphere is much less dense than Earth's and slowed down the airspeed to more correctly mimic Mars and it worked perfectly. I believe I saw that on PBS but I'm not sure. It was pretty amazing to see the forehead slaps when they realized testing at Mach 2 Earth density air was their problem and not the chute design.
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the7thearlofgrey
> wagnerrp
10/05/2013 at 15:26 |
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and here is the designated pilot
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the7thearlofgrey
> Rock Bottom
10/05/2013 at 15:28 |
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The S upersonic C ommercial A ir T ransport designated pilot
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frankfan42x
> Rock Bottom
10/05/2013 at 16:00 |
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Thanks for your reply and sharing the information
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frankfan42x
> wagnerrp
10/05/2013 at 16:03 |
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Thank you wagnerrp for schooling me in this matter. What did you do when it WAS shut down?
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wagnerrp
> frankfan42x
10/05/2013 at 16:37 |
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I was still a lowly undergraduate when it was shut down, however most of the CFD work I've done is in turbomachinery, which can get by which much smaller physical test cells. Physical testing cannot sample every part of the flow, or every possible boundary condition, so physical testing and simulation exist in symbiosis. Physical testing verifies the computational models, and the computational models fill in the gaps that cannot be physically measured or tested. Simulation will continue to need such verification until we get the computational power and capacity to actually run the math directly, rather than using simplified statistical models, and we're still a long long way off from that point.
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Jeffrey Lo
> Rock Bottom
10/05/2013 at 16:52 |
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I remember one story that our tour guide told us. Apparently there had been some Army helicopters that were crashing without explanation. After a few of them went down they brought one into the 40x80 wind tunnel. Good thing that procedure was to set everything up and then leave the area because they managed to get the rotor on the helicopter into a state (not sure if it was flutter or ???) where it started throwing rotor blades, and they of course went right out through the side of the wind tunnel. With the instrumentation and recording of data they were able to identify and fix the issue, but it must have been a scary sight inside the wind tunnel as that helicopter tore itself apart.
FrankenB5S4
> Rock Bottom
10/05/2013 at 19:37 |
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Awesome article. Love the pictures.
Whitehouse
> Rock Bottom
10/05/2013 at 23:44 |
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I noticed the scale model of the space shuttle is now parked outside if you check Google maps.
https://maps.google.com/maps?q=Moffett
bill
> Rock Bottom
10/06/2013 at 17:50 |
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When I was going to P-3 Framp in the late 70's they only run the tunnel at night because of power used, people living in Mountain View/Sunnyvale got dim lights from time to time
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frankfan42x
> wagnerrp
10/06/2013 at 18:55 |
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Thanks to your concise explanation I can readily see how both methodologies are symbiotic in verification and filling in the gaps as you say. Very enlightening. One is never too old to learn something new. Thanks again!
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Rock Bottom
> bill
10/07/2013 at 11:24 |
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It wasn't just us, but everyone on base was affected. All the big wind tunnels (which at that time was 7) and the arc jets had to coordinate power consumption through the Ames Power Management System (APMS). Also, in the late 70s NFAC only (!) had about 1/4 the power it has today.
It's awesome that you were at Moffett with the P-3s! Thanks for sharing your memory!
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Rock Bottom
> Whitehouse
10/07/2013 at 11:26 |
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It was painted white and black at some point and parked outside. It's a nice conversation starter!
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Rock Bottom
> Jeffrey Lo
10/07/2013 at 11:31 |
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We have put a handful of test articles down-stream... including the AH-56 Cheyenne! That may be the one you're remembering. That incident was around 1970 and was due to ground resonance, I believe.
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Rock Bottom
> Icemanmaybeirunoutofthetalents
10/07/2013 at 11:34 |
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The power grid here is pretty robust. Good thing!
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Rock Bottom
> Mark Out West
10/07/2013 at 11:42 |
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Thanks for sharing that, Mark! Were you involved with the programs?
While this tunnel did play a pretty big part in the development of the tilt rotor, I think the biggest reason the concept matured was the push from the NASA and Army aeromechanics guys. They saw a potential use for this technology several decades into the future and started working with industry to get the bugs worked out early. Great example of forward thinking people looking a little further down the road than the next election!
You can tell a Finn but you can't tell him much
> Rock Bottom
01/28/2015 at 11:24 |
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Awesome article and pictures. I saw your link in a comment today and can't believe that I missed this when it was first posted. Wind tunnels are so cool, especially supersonic/hypersonic wind tunnels. They allow for very cool stuff like Schleiren photography . There was a very cool special edition issue of Air & Space that I picked up this spring that had an article talking about supersonic wind tunnels and how they solved the choking effect at supersonic flow velocities.
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Rock Bottom
> You can tell a Finn but you can't tell him much
01/28/2015 at 12:18 |
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Thanks for checking it out! Yeah, I'm a low-speed guy myself. There's a bit of a rivalry between the low speed and high speed guys! They think we're slow and dumb, and we think their supersonic aerodynamics are simple. We're right ;)
My heart really lies with the full-scale rotor testing. The aerodynamic environment that a helicopter lives in is so complex that we still don't fully understand how they work or how to make them better. Your typical full scale rotor test will take data on 300 to 500 data channels (many of those being in the rotating frame). For comparison, your typical automotive test will take data on 6 channels or less.
Sidenote: If you like Schleiren, you'll love RBOS (Retro-reflective Background Oriented Schleiren) and PIV (Particle Image Velocimerty). Both were great tools for learning the composition of the rotor blade-tip aerodynamic environment. The picture below was taken at about 150 knots with a UH-60 rotor.
Tinfoil Hat in a thunderstorm, now with added diecast
> Rock Bottom
02/03/2015 at 07:17 |
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That's awesome! I finally got a chance to read it, very cool. I'm blown away.(sorry, bad pun)
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Rock Bottom
> Tinfoil Hat in a thunderstorm, now with added diecast
02/03/2015 at 10:24 |
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There's no such thing as a bad pun!