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Workshop Engineering
เข้าร่วมเมื่อ 14 ต.ค. 2016
Why Blackbird, DWFTTW Works
While Rick Cavallaro’s Blackbird, “Downwind Faster Than The Wind” (DWFTTW) . . . [or Directly Downwind Father Than The Wind (DDWFTTW)] . . . dates back more than a decade, it’s once again become a popular subject spurred by Derek Muller’s Veritasium channel video: th-cam.com/video/jyQwgBAaBag/w-d-xo.html.
While there’s endless chatter debating whether or not Blackbird can or does work, it seems clear (at least to me) that it does work as documented in the North American Land Sailing Association (NALSA) report: www.nalsa.org/BlackBirdDDWSR/NALSA%20Submision%20report.pdf which established a performance record of achieving a velocity ratio of 2.8 times wind velocity after a period of acceleration during which the cart velocity was always greater than the wind velocity. If you’re skeptical, I’d suggest reading this and these related reports before passing judgement:
www.nalsa.org/DownWind.html Summary of the NALSA test with more links
www.nalsa.org/BlackBirdDDWSR/Copy%20of%20Observers%20Report%20Appentix%201.xls NALSA test report data during 10 second record data interval
There are many shots at providing intuitive explanations of why Blackbird works and Rick Cavallaro notes that different explanations work for different folk as he discusses in his St. Francis Yacht Club presentation at: th-cam.com/video/X6oJpnSJyV8/w-d-xo.html. A great watch.
I find the most convincing video demonstration at: th-cam.com/video/5CcgmpBGSCI/w-d-xo.html (watch the chase car anemometer and wind vane).
While there are many related offerings, here’s a list of a few links:
A brief mathematical explanation by Steve Morris: docs.google.com/document/d/10qzwC8BmR3fr-ezvSveZ1cOJxZ_4gObOk3DHHaPp2GY/edit
A physics exam problem (see problem B2) How would you like to have only 45 minutes to solve this? www.aapt.org/physicsteam/2013/upload/E3-1-7-solutions.pdf
th-cam.com/video/yCsgoLc_fzI/w-d-xo.html A fun Veritasium follow-up with links to more
th-cam.com/video/GXtB9N6Oxds/w-d-xo.html Video of Blackbird setup before record run
th-cam.com/video/BvJZKZsUqgI/w-d-xo.html Video shot during the record run
CREDIT
Many thanks to George Junkin who became as hooked on this problem as I have. His questions, thoughts, analytical work and review have been of incredible value. With almost endless emails and phone conversations under our belts, I think we’ve both found this analysis to be a fascinating retirement engineering project . . . in other words, it’s been great fun.
While there’s endless chatter debating whether or not Blackbird can or does work, it seems clear (at least to me) that it does work as documented in the North American Land Sailing Association (NALSA) report: www.nalsa.org/BlackBirdDDWSR/NALSA%20Submision%20report.pdf which established a performance record of achieving a velocity ratio of 2.8 times wind velocity after a period of acceleration during which the cart velocity was always greater than the wind velocity. If you’re skeptical, I’d suggest reading this and these related reports before passing judgement:
www.nalsa.org/DownWind.html Summary of the NALSA test with more links
www.nalsa.org/BlackBirdDDWSR/Copy%20of%20Observers%20Report%20Appentix%201.xls NALSA test report data during 10 second record data interval
There are many shots at providing intuitive explanations of why Blackbird works and Rick Cavallaro notes that different explanations work for different folk as he discusses in his St. Francis Yacht Club presentation at: th-cam.com/video/X6oJpnSJyV8/w-d-xo.html. A great watch.
I find the most convincing video demonstration at: th-cam.com/video/5CcgmpBGSCI/w-d-xo.html (watch the chase car anemometer and wind vane).
While there are many related offerings, here’s a list of a few links:
A brief mathematical explanation by Steve Morris: docs.google.com/document/d/10qzwC8BmR3fr-ezvSveZ1cOJxZ_4gObOk3DHHaPp2GY/edit
A physics exam problem (see problem B2) How would you like to have only 45 minutes to solve this? www.aapt.org/physicsteam/2013/upload/E3-1-7-solutions.pdf
th-cam.com/video/yCsgoLc_fzI/w-d-xo.html A fun Veritasium follow-up with links to more
th-cam.com/video/GXtB9N6Oxds/w-d-xo.html Video of Blackbird setup before record run
th-cam.com/video/BvJZKZsUqgI/w-d-xo.html Video shot during the record run
CREDIT
Many thanks to George Junkin who became as hooked on this problem as I have. His questions, thoughts, analytical work and review have been of incredible value. With almost endless emails and phone conversations under our belts, I think we’ve both found this analysis to be a fascinating retirement engineering project . . . in other words, it’s been great fun.
มุมมอง: 1 063
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Branch Engine Mk2
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The original Branch Engine, while a bit strange, still follows the basic geometric rules used to design simple oscillators. The Branch Engine Mk2 throws most of those geometric rules to the wind to see if something skewed in every practical direction might run. While it does run, it’s certainly not an illustration of a useful design. But, it is fun to test the limits.
Branch Engine
มุมมอง 1082 ปีที่แล้ว
While seemingly a bit of a joke, the Branch Engine does have a purpose. It explores the impact of materials and construction upon whether an engine can run . . . and, if it does, how well . . . or poorly . . . it might run. It does run and we’ll measure its performance with a dynamometer. The construction of the engine wasn’t documented during the build but the video includes a few quick clips ...
Reading Optical Flats Part 2
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Beyond some hit and miss experimenting, much of what I’ve learned about interpreting optical flat fringe patterns comes from a 1950s DoALL book titled: “The Science of Precision Measurement”. Illustrations from this book and other DoALL sources are included with the permission of DGI Supply, a DoALL Company: www.dgisupply.com/page/page.header.about-dgisupply-doallcorporatefamily/ Although unive...
Engine Indicated Power - PLAN
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Indicated power provides a first, ballpark estimate of an engine’s power using the engine’s mean effective pressure (MEP), piston area, stroke and speed in the formula PLAN. But both MEP and speed can vary significantly, depending upon the engine design. As we’ll see in other videos, this is just a beginning since our real interest is in delivered power which is always less than and sometimes m...
Reading Optical Flats Part 1
มุมมอง 18K3 ปีที่แล้ว
I’m new to optical flat inspection, so bear with me as I walk through some of the things I’m trying to learn. This first of a series of videos presents the basics . . . possibly in excruciating detail . . . but, hopefully, a few points worth presenting to establish a firm basis for things to follow. I started using optical flats to evaluate progress while generating small lapping plates using p...
Hero's Temple Doors - Part 1
มุมมอง 2.9K3 ปีที่แล้ว
This is Part 1 of a multi-part series. While the temple doors concept was originally documented by Hero (Heron) of Alexandria, Egypt in the first century A.D., it is possible that the concept may have been conceived by one of Hero’s predecessors several hundred years earlier. The primary goal of this series is to demonstrate feasibility of the concept with a roughly 1/24 scale working model and...
Trailer p.s.
มุมมอง 1153 ปีที่แล้ว
This video might be considered a “Trailer p.s.” since it adds a bit of context for some of the images in the Trailer image sequence. While it begins a discussion of testing small engines . . . as well as some historical models . . . the video is also “just testing” some experiments as I wet my feet in this video production business. The video gives a sense of my shop and research wanderings sin...
Trailer
มุมมอง 1513 ปีที่แล้ว
This is just a visual sampling of the sort of stuff I play with. Some may appear soon . . . and others possibly much later. As discussed at the end of this trailer, videos will be grouped in sections, hopefully providing some logic to the overall content. This section, Recent Releases, will reflect only the trailer and the last few videos released so, if new to this channel, it’s best to simply...
Great video, thank you for taking the time to make this!
This was solved recently, a proper mathematical theory was provided
docs.google.com/document/d/e/2PACX-1vTDmYH5j9dYEpGLH4KU6m6eK20qljAOIdovb82uacTIwMtaSKqJiUxyGGCdvkvibSf5l82EYkec6I5a/pubdocs.google.com/document/d/e/2PACX-1vTDmYH5j9dYEpGLH4KU6m6eK20qljAOIdovb82uacTIwMtaSKqJiUxyGGCdvkvibSf5l82EYkec6I5a/pu
So I understand that to use these you need a special light? I bought one of these really cheap on ebay for a couple bucks years ago (no reserve $1 auction for a new-old-stock item) but don't see any paterns forming when placed on a polished metal surface no matter if viewed under daylight or artificial room light
I would say it's that the propellers are always trying to grab More air than the wheels are turning and the air being the open system source. No wind required
You were right on the money - until the "no wind required" part. The cart will in fact come to a stop pretty quickly when the wind dies. This is proven by both theory and real-world results.
@Rick_Cavallaro only air is required. No wind current is required. Only resting air is required. That clear enough for ya?
@@kdkinen I designed and built the thing and set 4 world records with it. I've given talks on it at NASA, Stanford, Google, and lots of others. That clear enough for ya?
@Rick_Cavallaro Alright well, I cannot argue with that. However, on the treadmill inside your room, there was no active wind only resting air. It was able to climb the treadmill with resting air. Does that not make logical sense why I am saying there is no wind required? Only resting air, And the props are always trying to capture more air than the wheels are turning. Leading to the runaway effect which we all love.
@@kdkinen wind is simply the movement of air relative to the ground. You can move the air over the ground or you can move the ground under the air. Not only can't you tell a difference - there literally is no difference.
I would enjoy a long discussion with you , John Borton, and Derek from veritasium
The wind is always moving forward across the blade in the direction that the blade is turning and the contact point where are the wind meets the blade is always moving down wind slower than the wind
Wonderful work all of you have done here please watch my video and I'll explain exactly what is taking place it is just like a high-performance ice boat sailing diagonally downwind the wind is always flowing forward across the sale or blade and the contact point is always moving down wind slower than the wind thank youth-cam.com/video/azNTzkPhx1s/w-d-xo.htmlsi=Ml27UxOdkDaDKmVF
th-cam.com/video/azNTzkPhx1s/w-d-xo.htmlsi=Ml27UxOdkDaDKmVF
What a shame if you don't do part 3. It's the best info on optical flats there is.
very helpful tnx
People watching this should consider that peices of granite from ancient Egypt have been found to be absolutely optically flat. How is this?
Can I use an optical flat to check flatness for a surface plate?
Hi there. Rick and I designed and built the Blackbird (with propeller assistance from Steve Morris) and hold the world records together. Your analysis is pretty remarkable in that your simulations and observations are amazingly close to our reality. Your compliment that the Blackbird appears to be set up "near optimum" is appreciated. You should know that I build a massive, gasoline engine powered 'treadmill' upon which we optimized (and broke and broke and broke) the Blackbird before taking it to the desert. Though there were a few issues in our first dirt runs (we'll get to your wheel slip comments), the vehicle performed very close to our own simulations. We did run it in higher and higher winds and at higher and higher speeds until I was begging Rick to slow down in fear of it blowing up (which it eventually did). We approached 60mph several times and regularly took it over 50mph. Of course top speed was not our record goal, but rather a multiple of the windspeed. We were initially working with a $5,000 budget (which included our own custom built ~18ft propeller) so I could spend very little on the chassis. I designed a craft which I felt could be safe at our design point (~25mph ground speed). It was made of wood I beams (TJI) from Home Depot and built up from there with steel, carbon, kevlar and fiberglass reinforcements. Salvaged BMX wheels, etc and other bicycle components you already obviously know about. Some (me) would never call home made propeller tips whipping past the back of the drivers head at over 150mph "safe" in any way. You reference Rick's presentation at the St. Francis Yacht club, so I'm sure you noticed the story of why he was the pilot and not me (recounted at 1hr, 11m and 41s of that video). Our original goal was 2x windspeed. Our thought was that if we could double the speed of the wind it would make it more difficult for skeptics to claim measurement error compared to say 1.1x. Our design point for wind was (as I recall from more than a decade ago) ~9-10mph. Our highest ratio we recorded was around 3.4x, and we often got over 3x, but due to conditions and limited time (and NALSA measurement rules which we found appropriately conservative), we didn't reach that under the constrained record recording conditions. All these numbers fit your simulations very closely. Your observation that an appropriate RC works over a rather broad range of wind velocities was our direct experience. I installed the sprocket cluster just so I would have a range covered, but as I recall we optimized on the treadmill and never moved it after that. Yes, a greater tailwind does deliver more power to the cart, and with a far bigger budget and thus safer and stiffer chassis, we could have raised the bar significantly. As it was, at our top achieved speed, there was something like 600 ft lbs of torque on the prop shaft feeding the propeller blades through a variable pitch hub I designed and machined myself on a mini-mill. As I said, I was literally on the radio begging Rick to slow down at times. I still can't believe it took the abuse it took. As to wheel slip, the first videos you can find of the Blackbird (it was unfaired and called the BUFC ... "Big Ugly fn Cart" at that time) show it with symmetrical rear axle lengths. During our first dirt testing day (see "BUFC blow up run with full audio), Rick exceeded the design point by quite a margin and blew up the top sprocket. He reported an odd "surging" just before the failure (just as you suggested). We closely watched all our video and discovered that he was saved from tipping over (equal and opposite reaction to the aforementioned propeller shaft torque) by one wheel lifting slightly and losing enough traction to create the repeated surge in harvested power. This self limited top speed (and torque reaction) and also hammered the top sprocket (just as you suggested). Before we went out again, I revamped the chassis to extend one axle by several feet which gave the Blackbird it's odd asymmetrical look. BTW, the BUFC version of the craft had a fixed pitch propeller hub (relating to your fixed pitch analysis). It wasn't until Larry Page stepped up with sponsorship that we had the funds to dress up the renamed Blackbird and install the variable pitch propeller hub and controls. As you can conclude, the ability to adjust pitch on the fly doesn't really increase the top performance of the craft, but rather allows it to accelerate faster and 'self-start' in lower winds. If you review the other "BUFC" videos and compare them to the later Blackbird videos, you can see this impact. Overall you did a really great job here. Seeing someone applying good engineering analysis and comparing to actual results was refreshing given the literally tens of thousands of times Rick and I have been called frauds and idiots over the last 15 or so years. I have many, many build pictures if you're ever interested and you might also be intrigued by the upcoming possibilities to truly smash this record given the interest of a certain energy drink company to sponsor such. Composite F1 factory built with truly giant, counter-rotating propellers and generator/motor drive is being discussed. Fun if it were to happen. Thanks and very well done. John "JB" Borton Thin Air Designs team principal.
John, Thanks very much for your detailed and kind comments. You’ve answered some of my lingering questions. This is the first I’d heard of the giant treadmill. Wow! I’d enjoy seeing what it looked like. Also the variable pitch mechanism. I’m assuming that the potential generator/motor design you mention is similar to that in Rick’s yacht club talk (wheels drive generator that drives motor that drives prop). Since it appears that peak performance (cart/wind velocity) is very sensitive to overall efficiency, I wonder if you’ve gotten to overall efficiency predictions for the generator/motor/counter-rotating prop combination.
th-cam.com/video/azNTzkPhx1s/w-d-xo.htmlsi=Ml27UxOdkDaDKmVF
docs.google.com/document/d/e/2PACX-1vTDmYH5j9dYEpGLH4KU6m6eK20qljAOIdovb82uacTIwMtaSKqJiUxyGGCdvkvibSf5l82EYkec6I5a/pub
A couple of questions. In the videos showing this demonstrated, slow down the video. At the start, notice the propeller is turning one direction. But when you see the flag pointing towards the rear of the vehicle showing it is traveling forward faster than the wind speed, you’ll notice the propeller is turning the *reverse* direction. Because the *relative* wind is now toward the rear, this is indeed consistent that the forward propulsion is being provided by the wind. But the problem is with the propeller *directly* connected to the wheels shouldn’t that reverse the direction the wheels are turning? I’ve not seen anything of this nature discussed in the demonstrations. That the wheels turn in the same direction would seem to suggest some type of gear conversion that would allow the wheels to turn in the same forward direction regardless of the propeller spin direction. Also, in the small toy models demonstrating it on treadmills you can see there is no such gear conversion being used. This is puzzling. I like your analysis and demo using a parachute analogue. I’m surprised this worked, but I have to say there is a flaw. You see the “parachute” is not moving faster than the wind speed, even if the car is, as the wind is still pushing the parachute *forward*. If the parachute were moving faster than the wind speed the relative wind would push it *rearward*. This is a key distinction from the actual case. In the actual scenario the *relative* wind is pushing rearward against the propeller. In fact I draw the conclusion your parachute analogue would NOT work if the parachute were made to move faster than the wind speed, since then the *relative* wind would move the parachute *rearward*. Here’s a key deduction you can draw from that fact: it is something about the nature of the propeller itself that allows it to work in that case, but not in the parachute case. Here’s what I think that is. Much has been said about this scenario being different than a sailboat tacking into the wind because the vehicle is moving directly downwind, not an angle. But the thing is the propeller, i.e., the sail, is moving at an angle to the wind! This is because the sides of the propeller are *angled*. I haven’t looked at all the video discussions of this phenomenon but I think this fact is not focused on: it really is the same as tacking into the wind with a sail at an angle to the wind direction. If this fact were stated I think the phenomenon would be easier to understand. Robert Clark
Addressing your thoughts about sail driven land vehicles, see the North American Land Sailing Association: www.nalsa.org/ At www.nalsa.org/faq.htm they say: “The slowest point of sail for a land yacht is dead downwind when it sails a little slower than the wind speed. By sailing at 45 degrees off directly downwind the yacht can sail much faster than the wind. The 'velocity made good' down wind is often over twice as fast as sailing directly down wind.” Note that the often contested Blackbird performance is Directly Downwind, i.e., course changes such as gybing (jibing) are not allowed. The downwind “Velocity Made Good (VMG)” is the performance of interest but downwind VMG is the same as cart speed when traveling directly downwind. But, I think that this is moot since, unlike a sail driven vehicle, Blackbird’s performance does not increase traveling off of the wind. If you haven’t seen it yet, Rick’s St. Francis Yacht Club presentation at th-cam.com/video/X6oJpnSJyV8/w-d-xo.html is an excellent summary of analogies offered to explain Blackbird. While Blackbird’s propeller blades are airfoils, I don’t find the sailboat analogy that helpful (except to suggest how propellers work). Blackbird exploits the velocity difference between the ground and wind with the overall mechanical advantage and efficiency of the drive transmission and propeller determining the system’s performance.
brilliant you deserve more visitors to the videos
Superb, great work!
It's been a while now. Are you still going to make part 3? I hope so. Thanks.
What lighting are you using to get a yellow glow?
tnxs god we have ECM to advance, retard or even compensate cylinder wear.
Nice
Hey, I am currently doing a research paper on this idea Can you share the document of the calculations and graphs please? This would really help me
Wow, fascinating work. Can you share the document of the calculations and graphs please?
I am very impressed with your analysis. I guess Rick is the real deal.
First class content presentation. Many thanks for this.
Fascinating.
Thank you for putting all this together. I look forward to part 3. My Optical Flat light is green for a 10.7 millionths per fringe. I wonder if a light is made that gives 10 millionths per fringe? I prefer the green simply because it is NEARLY 10 millionths.
Please never stop making videos sir, I hope I run across you irl and that I can pick your brain sometime.
I am so excited for the next video in this series, and to continue to learn from your channel. I have been a bit obsessed with flatness as a by-product of restoring antique tools. Mostly hand tools. I know it is orders of magnitude more precision than I need, but after watching your videos in this series I am inspired to pick up a surplus optical flat. Metrology is my second favorite (due to expense) hobby, and before your video I believed this level of precision was unobtainable. If you enjoy making videos, I hope you continue. I am interested in soaking in all the information from you that I possibly can.
Not only is the model very nicely made, but the analysis is excellent. It is surprising that some authors in reputable publications claimed that the temple doors were opened using Hero's aeolipile steam engine. That was not correct, as demonstrated here.
This is a very nice demonstration on PLAN and the effects of engine size and displacement. I have a question which I need to explain in some detail. The Stephenson link and its variants allowed the steam engine operators eg locomotives, to vary the valve timing as needed. They could continue to apply full pressure throughout the whole power stroke (TDC to BDC) when taking off from stationary at low RPM, giving maximum torque for acceleration. Full steam pressure was still being applied when the exhaust valve opened at the end of the power stroke, causing a loud puffing sound. However, after reaching cruising speed it would be inefficient to let full steam pressure escape through the exhaust valve. Efficiency could be improved greatly by shortening the intake by closing the intake valve very early in the power stroke. Then the steam which entered early was left to expand as the piston moved. Then the steam being released through the exhaust valve at the end of the power stroke was at a much lower pressure and less power was wasted. The steam was used more efficiently. I recently went on a tourist trip on the small steam powered launch Earnslaw on Lake Wakatipu in New Zealand. The operator was not making use of the Stephenson linkage provided in the engine. Instead he was partially closing off the steam valve supplying steam to the engine. I tried to explain to the captain that they should use the Stephenson linkage, but he didn't get it. The question is, how much difference does it make? If they only need quarter power they could cut the steam supply to one quarter the pressure. Alternatively, they could have the inlet valve cut off about one quarter way down the stroke. Then during the rest of the stroke the volume would increase 4 fold and pressure would drop 4 fold and exhaust steam pressure would be reduced to one fourth. Thus the exhaust steam pressure is the same as cutting the supply steam to one quarter pressure and keeping the inlet valve open throughout the stroke. On this basis it seems that the two methods are equivalent. This is not what I expected. Thanks for you TH-cam videos! PS. I also went on a very similar triple expansion steam launch in Connecticut.
This is a fantastic channel! He seems to know everything there is to know about engine thermodynamics, construction and measurement.
Great work. I've been following this topic for many years. I'd love to take Blackbird to the next level. A more automated vehicle that can shift between propeller and turbine mode. Telescopic and dynamic aerofoils to extract energy from crosswinds. Roadways and railways that canalize any available wind, passible and dynamically to optimize energy transfer to a (rail)vehicle. And the absolute pinnacle: extracting the speed differential between surface coundary layer air speed and higher altitude air speed to power a ground effect flying craft. With efficient floating wheels or tracks, a vehicle could "roll" on the water similarly to blackbird and sail DDWFTTW. It will ask a lot from the engineering, but Blackbird shows there is some rooms of inefficiencies to be introduced, as it went 3x wind speed with somewhat rudimentary drivetrain adjustments. What would the ideal scale for a Blackbird competitor be, to optimize power and drag? Mass grows with the cube, wind power with the square, sort of. Would a cart manned by a squirrel manage 4X wind DDWFTTW?
So THIS is what Gingery was talking about.
I only watched the introduction. The plane has his own energy source else it will not travel faster than air. Blackbird has no internal energy source so in order to exceed wind speed directly downwind it will need to have an energy storage device (and it has). Since a very limited amount of energy is stored by the blackbird it can only travel above wind speed for a limited amount of time proportional with the amount of stored energy . Energy in case of direct down wind blackbird version is stored in the pressure differential created by the propeller (air is a compressible fluid).
@@electrodacus You claim the time it runs above-wind for is irrelevant, do you further claim it it takes 90 seconds to reach a stable above-wind speed as shown, and doesnt measurably slow down for say, 24 hours before being manually stopped, that 24 hours above-wind was powered by the 90 seconds of acceleration?
I feel like this conflicts with Derek’s explanation over on Veritasium
I just re-watched Derek’s explanation in: th-cam.com/video/yCsgoLc_fzI/w-d-xo.html . Could you be more specific about the conflict you see?
It only conflicts in being an order of magnitude more perspicuous. This video outclasses every other video I've seen on the topic over the years, and lays out clearly in the first 10 minutes what people need to know to resolve the vexing paradox.
I think the units would be a bit more clear if they written as "μin" for millionths of an inch and "μm" for micrometers
Really wonderfully cogent and complete analysis. It's astounding that this is still even being debated. It points to a fundamental flaw in our thinking, in how easily we can let even well-developed intuitions lead to entrenchment. I took a brief look at this back when it was still a thought experiment, had my thermodynamics boots already pulled on and ready to do battle, right until saw where the untapped differential in the system is. Quite stellar stuff. Thank you.
Is weird but helium light is not monochromatic, sodium lamp light is and the wavelenght is 589. Why they say helium in the manual?
I believe the source of monochromatic light you have is a sodium lamp not a helium lamp.
The DoALL literature says helium. Others may use sodium. Charts that I have say that helium wavelength is 23.2 microinches while sodium is 23.6 microinches so they're very close; just at the breakpoint between yellow (helium) and orange (sodium).
@@workshopengineering Yeah i saw in video number 2. Is kind of surprising for me, because for what i know helium light is not monochromatic, maybe there is some kind of filter to absorb some of the emission lines. I made my own with a sodium vapor lamp i bought on ebay and it works very well even if it needs about 5 min to heat up to working temperature. Thank your for your answer and your video explanations!
Much appreciate your insight and knowledge of this complex subject
Thanks. But just learning myself.
Eagerly awaiting part 2
Awesome explanation , well done ! Subed directly !☆ -One question i always asked myself , but never got answered nl.: -What if we use a monochromatic ultraviolet lightsource , the wave lengte is way shorter. Meaning we could even get smaller measurement scaler ? Or am i misding something ? Grtzz from the Netherlands Johny geerts
Yes, if the shorter wavelength were still long enough to see (or use an imaging sensor that could). But there are other factors such as view angle (that has significant impact upon fringe spacing calibration . . . to be discussed later) and light bandwidth and part surface finish that affect fringe width. Conventional monolights are probably a reasonable, practical sweet spot for typical measurements without more complex setups.
@@workshopengineering thanks for answering my question ,! Good video´s a Joy to view
Thank you so much for this great series! Are you planning to issue the next video in the series? I've subscribed so I don't miss it if you decide to publish it.
Part 3 in the works and more planned.
This is the very best explanation of how optical flats work that I have found. I sincerely appreciate all the work you put into this video series. Merry Christmas and Happy New Year!
Thanks for the kind words. Hopefully more to follow.
Agree 100%. Saving this one for future reference.
Wow, great video !
Thanks!
Sir, I like this video pretty much and will wait for your next!
Thank you for making a great easy to understand video. Wish I'd seen this earlier.
Fantastic information, thank you!
Glad it was helpful!
@@workshopengineering Just watched it again and printed out a bunch of screenshots (after receiving our flats and building the monochromatic light box). Thank you!
Nice video!