Plasma Wind

For the Love of Technology

We love technology (from the Greek, literally “know-how”). It’s so…so… American.  We’re a culture evolved from all the do-it-yourselfers, early adopters, pioneers, independent thinkers that left Europe a few centuries back, so its only natural that we want to know how to do something better, easier, or maybe so that we can make a buck, or maybe just because we like knowing how to do something that other people can’t.  This is something we seek out and embrace.

 But the implementation of new technology is a different story.  New technology faces the challenge of displacing the incumbent technology.  When people are faced with this decision, they make a reasonable assessment: does the new technology and its claimed benefits outweigh the difficulty and risk of replacing the old technology, especially when the incumbent way is working, making money, is can be counted on?  (Way) More often than not, the incumbent wins, and the new technology is not implemented. The difficulty of implementing new technology and innovations is well-documented and analyzed in Clayton M. Christensen’s books, The Innovator’s Dilemma, and The Innovator’s Solution.  Christensen basically shows that new technology has to enter “from the bottom up”, by providing innovation for the needs of customers that aren’t being served by the incumbent. 

 A while back, considerable discussion arose from John McGowan’s article in the Space Review regarding technological innovations that might make cheap access to space possible.  I think the significant contribution of McGowan’s article is the reiteration of the fact that technological development requires many trial-and-error attempts in order to work out all the kinks. 

 I provided some comments to the article, in an attempt to shed some light on specific approaches to technical innovations for low cost space access.  In my opinion, there is almost no better reference to this issue than John London’s seminal book, LEO on the Cheap, which can be downloaded here.  London points out that simplicity and design choices can radically alter development and operational costs, and that there are cultural issues involved as well. He provides excellent examples as well as recommendations.  Col. London (ret) is a rather amazing person, and is one of the few people I know to have served in the Air Force (as an officer), and in NASA and the DoD (as a civilian), and has remained a tireless supported of the "New Space" Industry.  Not too long ago this was considered fringe territory, and it was John who coined the term the "radical rocket underground".  So he's not just talking out of his hat, he's been there, done that.

 LEO on the Cheap essentially provides a roadmap on how to develop low cost space launch systems.  And in fact, many of his recommendations and observations have found their implementation in some of the current space launch systems, such as SpaceX, Armadillo Aerospace, XCOR, and others.

 Finally, I think its worth noting, as I did in my comments to McGowan, that we may eventually rediscover the advantages provided by spaceplane-type launch vehicles which take off from a runway, fly an envelope-expansion type flight, and then return to land. Despite their larger dry mass fractions, aircraft-type flight operations allow incremental flight testing, and hence, many more trials for a given development budget.

 But the question remains as to why this has taken so long.  This is not a simple question to answer, because there have been, in my opinion, quite a number of contributing factors.  But, my best attempt at putting it in a sentence or two goes something like this:  the Space launch industry emerged largely as the product of post-World War II industrial practices and the success of large, government-led projects.  Subsequently, the aviation and aerospace industries were largely usurped by cold war imperatives.

 Further discussion and explanation of what I mean above will require additional posts, which I’ll provide later.  But the upshot of this, at least for Americans, is that launch vehicle design, development, and the selling of launch services got wrapped up with only one customer, the U.S. Government.  The U.S. Government became the incumbent, and it’s taken a long time to create and find markets for these alternative launch services.

 I have to remind myself that new markets have to be created.  They are created when there is an exchange of things between someone who wants and/or needs something, and someone who has something to offer.  Usually, when someone wants something that doesn’t currently exist, creative people scramble around to provide that something.  However, if a creative person has something that they are offering, and no one wants it at the moment, then it sometimes takes a while to find someone who does want it, and sees its value.  Oftentimes, people don’t even know what they want except more/better/faster/cheaper of what they currently have. 

 How does this apply to our current launch markets?  We have people who need launch services, and we have people who provide those launch services.  The people who need launch services want more/better/faster/cheaper launch services than they have now.  Incumbents, like Boeing, LockMart, Orbital, have the advantage.  This is the innovator’s dilemma.  New launch providers, SpaceX, Blue Origin, TGV Rockets, et al, are seeking ways to “enter from the bottom up” by providing lower cost services to customers who aren’t being served by the incumbents.  This is the Innovator’s Solution.  And I think it’s going to be successful beyond our wildest reckonings

New Stuff, as far as you know

I know its a bad habit, but I've found a good source of seemingly new material to post about:  some of my previous posts.  Let's face it, you're not going to go back and dig through my archives from May to read more of my posts (unless...you....have...some sort of....obsession....yikes...)

So I'll do you a favor, and I'll repost a few of what I consider to be some of my better earlier posts, posts you never read because nobody was reading them (as far as I know). Here's a good example (maybe others will follow):

The Perishability of Technology

One aspect of technology that particularly fascinates me, is the process of technological degeneration, i.e. how technology gained can in fact be lost. We tend to think that the world we inhabit now represents the acme of technological progress, and in most of the ways that matter, this is true.  Our current technological prowess has emerged after thousands of years of more or less continuous progress, one discovery leading to another, several advances combining together to foster one great leap forward, or a new discovery.  James Burke’s famous television documentary Connections provided many fascinating accounts of this technological advancement. 

 Yet this steady, upwards-moving progress is not necessarily a given.  Furthermore, advancements made are quite perishable.  Consider, for example, that of the Roman Empire.  At the peak of this great civilization, numerous important technological advancements had been made in civil engineering, including structures (the barrel arch), materials (concrete), and hydraulics (aqueducts, siphons, valves), as well as the important advancement of how to organize and execute large projects: the technology of project engineering.  However, as the empire fragmented and eventually dissolved, so too went their technological capabilities.  Following the collapse of the Roman Empire, building technologies in Western Europe would not equal what the Romans achieved for nearly 1400 years (say 400 A.D. to the 18^th century).  I recently read where a large Roman bronze valve, used for water flow control, was finally taken out of service, having performed satisfactorily for over 1500 years. 

 Other civilizations have also had highly developed technological advancements that would not be equaled for millennia.  The ancient Egyptians had a technological civilization that was so advanced, that it is still a wonderment to this very day, as it was to Medieval Europeans, the Romans, the Greeks, and the Persians.  The great pyramid at Giza was the tallest man-made structure in the world until it was finally surpassed by the Eiffel Tower ; build for the Exposition Universelle of 1889. 

 Yet these civilizations, and many others (Mohenjo-daro, Tiahuanaco, Ba’albek), grew, reached their zenith, declined, and eventually disintegrated, usually leaving behind remnants of their past greatness.  The reasons for their declines are multifaceted, and not always clearly understood.  But my question is, what happens to the technology as your civilization declines?  Do you know someone that used to know how to do some process, but they’re no longer alive?  Perhaps you remember when things actually worked, but they don’t any more.  Do you just settle for less, and tell your children about the good ‘ol days when we used to have running water and telephones? 

 The idea of the perishability of technology I find very interesting, and somewhat disturbing, because it suggests that our continuous progress is by no means inevitable.  Sure, you’ll have a world war now and again, but the important technological civilizations survived, rebuilt, and in fact, net technological progress was often made.  But what about some other global catastrophe?  Or perhaps there could be some sort of gradual disintegration of civilization, like what happened to the Roman Empire, causing us to sink back into a more primitive and less technologically-capable condition.

 I often see movies and dramas about what happens in the aftermath of some great catastrophe or societal collapse (The Road Warrior, From Here to Eternity, Waterworld, The Postman, etc., there’s quite a list), and you see people trying to cope with what’s left of their civilization.  What you don’t see (because it’s hard to depict and perhaps not particularly dramatic) is people making the choice between slumping back into using less technology, or trying to maintain and improve what ever technology is left.  This process is composed of thousands of smaller choices that you make every day, throughout the day. “I’m going to go to my job today”, “I’m going to read a book on how to do something today”, “what can I create that’s new to me today?”, etc. 

 It seems that most of us would make the choice to keep trying to move forward, to maintain and improve existing technologies because we prefer them.  This approach to living is well articulated in Kevin Kelly's recent column “The World without Technology”:

http://www.kk.org/thetechnium/archives/2009/03/the_world_witho.php

So even if we had a major breakdown in our civilization, for any number of reasons, there might still be enough people around to recover, and preserve whatever technological gains we had made.

 And yet, we know from the historical record that these massive failures of civilization do occur (as previously discussed above), and that they can take thousands of years to recover from.  Perhaps some technology is lost for good (ref 1, 2).  Why does this happen?  Maybe that’s the question I’m asking. 

 These questions have direct bearing on the issue of humankind's expansion off the planet.  I will be exploring these questions and the general issue of off-planet expansion as part of my regular postings.  By giving consideration to the processes of how technology can be lost, in addition to how it is gained, perhaps that will provide some insight into our motivations for continuing to know more, to understand better, and to move forward and outward.

 References

1.  The Technology of the Gods; D.H. Childress; ISBN 0-932813-73-9

2.  Ancient Man:  A Handbook of Puzzling Artifacts; W.R. Corliss; ISBN 0-915554-03-8

How this Blog got its Name

In case you were wondering

yes, that's me, and this is what I do.

It had to happen eventually

In the life of every blog, the time comes when the blogger will eventually proffer some lame excuse about why they haven't been posting much lately.  For Plasma Wind, that time has now come.  Folks, I've been a bit busy with with work (which is a good thing actually), and, as suggested by the previous post, family matters have has some significant precedence in recent months. 

However, I do want you loyal readers to keep checking back.  I feel a creative surge coming, and I've got some good posting in the offing.  For example:  The next posting of the history of the ATR development is nearing completion: "A Brief History of ATR Development: the Middle Years 1945-1990.  Close at its heels will be the subsequent and (possibly) final section: A Brief History of ATR Development: The Recent Past 1990-present.

Also in the works is the another post (maybe posts) on ATR applications, dealing specifically with aircraft, aerospace craft, and launch vehicles.

Plus who knows what additional enthralling and heart-warming posts may emerge spontaneously.

In the meantime, take a look at this video.  Sit back, turn up the sound, and see what airbreathing propulsion can do for you. 

A Memorial: Robert C. Schindler 1928 - 2009

Rocket scientist, inventor, classic car enthusiast, green thumb, loving husband and father, Robert C Schindler of Rancho Murieta CA died on October 9 at his home with his family at his side.  He was born on April 5 1928 in Buffalo NY, one of identical twin brothers (Robert and Richard), to Carl Joseph and Marion Tangelder Schindler.  He was 81.Mr. Schindler was very unassuming and few were aware of the breadth of his pursuits and the scope of his accomplishments.

Rocket Designer and Inventor

Bob was a major contributor to the design and development of liquid propellant rocket engines (at Bell Aircraft (Niagara Falls NY) and at Aerojet (Rancho Cordova CA)).  During his 50 year career, he was responsible for the design of monopropellant and bipropellant rocket engines and components in thrust classes from 5 to 1.5 million pounds using cryogenic, earth storable, space storable, gel and halogen propellants.

Bob’s career began at Bell Aircraft, starting in 1950.  While at Bell, he made significant design contributions to the Nike-AJAX missile, the Rascal engine and the engine used in the B-58 powered pod.  He also provided design solutions for the Hustler and Discoverer/Agena space engine (which were applied to subsequent engines).  He supported  the design of the Bell 8096 engine - variations of which were used on Thor, Atlas, and Titan launch vehicles as well as on spy satellites and the two Mariner Mars probes.  It was at Bell Aircraft that Schindler conceived and developed the straight-drilled aluminum nozzle concept, in which regenerative cooling passages in a converging/diverging nozzle could be formed from straight-drilled holes arranged in a circle, but drilled at an angle.  This approach was used with great success on the aluminum nozzle of the Bell 8000-series rocket engine.

In 1962, Bob moved his family out to California and joined the Aerojet Corporation.  He remained at Aerojet until his retirement in 1993.  While at Aerojet, he served as design engineer, engineering supervisor, program manager, and Chief Engineer for Engineering, Test, and Research.  He was a key contributor to Aerojet missile defense systems efforts and in 1987 he was awarded the Aerojet RB Young Award for Technical Excellence.  He was named (with colleagues) on two patents.  These contributions were subsequently used on a number of Aerojet products, most notably the Space Shuttle Orbit Maneuvering (OMS) Engine, which is still in use today.

After his retirement he served as consultant to Aerojet and to Stone Engineering (of Huntsville AL).  In 1999 he was asked to serve as technical advisor to the NASA Advisory Council Task Force’s Proton Investigation Working Group which conducted meetings in Russia focused on the findings of the Russian investigation of two Proton Launch failures.  His contributions were recognized by USAF (ret) Lt. Gen. Thomas Stafford USAF (Task Force chair and former Gemini, Apollo and Apollo-Soyuz astronaut).  The resultant remediation of engine design and service procedures resulted in the successful launch of the ISS (International Space Station) Service Module on the Russian Proton launch vehicle.

Letters, Travel and Technology

Throughout his life, he appreciated automobiles (especially of British design) and owned several including an early Lagonda, a 1954 MG TF, two Jaguars, and two Alvis.  He often drove brides to weddings in his 1937 Alvis Speed 25 and enjoyed participating in Rancho Murieta Independence Day parades.He and his wife Rita enjoyed travel.  During the course of their 55 year marriage, they visited England, Ireland, Scotland, France, Germany, Belgium, Luxembourg, Italy, Canada, Mexico, Guatemala, Costa Rica and New Zealand.  Additionally, in a professional capacity, he visited Moscow, Korolyov and Voronezh, Russia.

Bob had an active retirement, participating in a wide variety of different activities.  His home in Rancho Murieta, which he designed himself, reflected his appreciation of the style and features of French country homes that he visited with Rita. One of his particular passions was gardening.  He created a series of beautiful and ever-expanding gardens around his Rancho Murieta home, and these reflected his appreciation of European gardens visited during his travels.

As for arts and letters, Bob served for a time as a volunteer docent at the Crocker Art Museum (Sacramento CA). He kept a personal library with extensive selections (all of which he read) on World War II, political thought, recent global conflict, American history (especially the founding era), democracy, discovery, technology, invention, war, science, aircraft and space travel.  He possessed an interesting collection of fantasy and science fiction (including some very early works).  He also studied classical literature and great works, philosophy and religious thought.  His collection included materials on travel and travel destinations, gardening and the environment, and automobiles (classic and new).He was active in the Roman Catholic Church, most recently serving in a number of volunteer capacities at St. Vincent De Paul Church in Rancho Murieta CA.

Family and Friends

Bob is survived by his wife (of 55 years) Rita, his three daughters (Carla Bossard and Paula Schindler of Huntsville AL and Sara Schindler of Placentia CA) and their families, and also by his six grandchildren.  Bob was the eldest sibling in his family.  He is survived by his twin brother and his other brother and sisters.He was appreciated as a generous and faithful friend.  His death is mourned by family, friends and neighbors.

On a personal note, I had the great pleasure of working with Bob professionally during the first years of my professional career, when I joined Aerojet in 1986.  At that time, Bob was serving as Chief Engineer for Engineering, Test, and Research.  I found him to be an extraordinarily gifted designer, engineer, and manager, and very approachable.  One of the things I most appreciated about Bob was his skill at the understatement, of understanding subtlety and nuance.  Yet he could very quickly cut the heart of a design issue, a skill which he brought to bear most notably when investigating the causes of two Proton Launch failures while working with NASA’s advisory council task force.

Bob was also my father-in-law, and became so when I married Carla in 1991.  We came to know each other very well during the more than twenty years of our association, and I’m the better man for it.

Bob told me that he considered himself a rocket designer, and not a “rocket scientist”, and that this, for him, was an important distinction.  He also told me that in looking into the future, he saw that there were two things that he considered particularly critical for the continued survival of mankind, and those two things were human spaceflight, and nuclear energy.  Over the years, I’ve come to better understand the wisdom of that observation.

Our civilization moves forward from the continuous contributions of many individuals, each adding some portion of their own, individual creativity, and knowledge to the aggregate.  And it is the sum of these contributions that will make it possible for our civilization’s continued survival and our eventual expansion off of the Earth’s surface and out into space, and to continue to make beauty and good.  I think Bob would be pleased to know that he had been able to make significant and sustained contributions to the betterment of mankind.

A Brief History of ATR Development: The Early Years 1900-1945

The history of Air Turbo Rocket development is surprisingly long, beginning early in the twentieth century.  In significant ways, it parallels both the development of rocket engines, and that of turbojet engines as well.  Similar thinking as to the motivations for development and the solution to technical problems are found in all three of these of propulsion development trajectories.   

The fact that rocket propulsion proceeded turbojet propulsion by centuries has significant bearing on the development of the ATR.   Motivated by the desire to improve rocket engine performance, especially at low speeds and low altitudes where most rocket vehicles start their journey, early developers looked for ways to utilize some portion of the available atmosphere in order to increase the effective thrust per unit mass flow rate of on-board propellant usage.  We know this metric today as the specific impulse.   

During the period of time from the beginning of the twentieth century to the start of World War II, the development history of the ATR is almost completely dominated by the work of one man:  Robert Hutching Goddard.  It is likely that other ATR development work on-going during this period, however Goddard’s work remains the most significant, and has had the most overall influence on the resulting development trajectory of the ATR.  

Few propulsion workers have been as prescient or innovative as Dr. Goddard, the man who designed, built, and tested the world’s first liquid bi-propellant rocket engine.  As early as 1930, and probably earlier, Dr. Goddard recognized that rocket propulsion was very inefficient at low speeds and at low altitudes, but if some use of the available atmosphere could be made, such as by the incorporation of propellers or fans, then the overall propulsion efficiency could be improved.  It was at this time that Dr. Goddard first conceptualized the integration of a turbine and fan with a rocket motor.  The design that he proposed is, in fact, the first Air Turbo Rocket engine ever conceived.  He described his design, its applications, and the motivations for developing such an engine in an article he wrote in the March 1932 issue of Scientific American: “A New Turbine Rocket Plane for the Upper Atmosphere”.      

In Goddard’s configuration, rocket motors impinge against turbine blades which jut into the rocket’s exhaust.  The blades are affixed on the outer circumference of a larger fan.  The rocket exhaust causes the fan the spin, producing additional thrust by the fan’s reaction against atmospheric air.  In this manner, the rocket can produce significantly more thrust while still in the sensible atmosphere, as it climbs up and out.  There are two turbine-fan assemblies, configured such that these assemblies could be translated laterally in and out of the rocket exhaust.  Turbine blade rows on each fan assembly were staggered such that they could interdigitate within the rocket exhaust, providing a multi-stage turbine expansion process.  He called his new engine concept the “rocket turbine”.   

Goddard continued to develop his ideas on the rocket turbine engine concept.  Goddard was unique in many ways from his contemporaries and predecessors, in that he actually designed, built, and tested what he conceived of.  Dreams, Ideas, and notional concepts are, by comparison, easy to come up with.  But actually fashioning them out of materials, and then testing them, is much more difficult and time-consuming.  The development of the rocket turbine engine was no exception to Dr. Goddard’s approach.  During the period of approximately 1930 through the start of WWII, Goddard designed and built a number of sub-scale rocket turbine test bed engines, as well as all sorts of other amazing technical innovations, such as turbopump systems for liquid rocket engines, gyroscopic-based guidance, navigation, and control systems for rocket vehicles and aircraft, and the development and testing of ion propulsion.  

Much of Dr. Goddard’s later work took place in Roswell, New Mexico, where he maintained his household, a large test range, launch tower, and shop.  He was active in the Roswell Rotary Club, and in the Roswell community in general.  After Dr. Goddard's passing in 1945, his wife Esther began donating his rocket materials to the Roswell Museum and Art Center (RMAC), beginning in about 1949.  In 1969 the RMAC dedicated the Robert H. Goddard Wing of the museum.  The RMAC has perhaps the finest collection of Goddard Artifacts in the world, and includes a recreation of his workshop in the Robert H. Goddard Collection of Liquid-Propellant Rocketry, as well as the actual launch tower from which he flew many of his rocket vehicles.   

In 2003, my good friend and colleague, John Bergmans (of Bergmans Mechatronics fame), visited the RMAC, and the Goddard Exhibition.  He took many pictures, and was kind enough to share them.  Shown below are two pictures of the reproduction of Goddard’s workshop.   

These photos are strongly evocative of images we’ve seen before, of Dr. Goddard in his shop, toiling away on a rocket vehicle laying on its side.    Outside the museum, Goddard's actual launch tower is displayed:

A commemorative plaque rests at the base of the launch tower:

However, the most astounding discovery at the RMAC were some of the artifacts shown in the museum.  To his surprise and astonishment, John Bergmans recognized that some of the artifacts displayed were actually sub-scale prototypes of the rocket turbine engine concept Dr. Goddard has proposed in the 1930's.  Due to the very small number of workers in the ATR field, John was very likely one of the first people to recognize these engines for what they were: the earliest working prototypes of an ATR engine.  Shown below are some of John’s photographs of the prototype.  

As can be seen, the turbine/fan assembly is made from a single sheet of metal, cut and folded to produce the fan blades, and also the turbine blades.  The tan cylinder on the lower left is the rocket motor which produces the hot gas to drive the turbine/fan assembly.  It is likely that this rocket motor used a solid propellant, as Goddard had done a great deal of development of solid rocket motors, and would possibly have had solid propellant materials at hand.  

A close up of the turbine blade assembly shows a re-entry turbine passage, making the turbine portion of this engine a partial-admission, re-entry turbine configuration.

The rocket turbine concept was later featured in a number of popular magazines of the time, including the December 1931 issue of Popular Science , and the December 1932 issue of Modern Mechanics and Inventions, the cover of which is shown below:   

Although these articles help popularize the rocket turbine concept, they did not always provide an accurate depiction of what Goddard actually had in mind, and often were more or less simply the creation of whatever graphic artist the magazine had assigned to doll up the story.   

Nevertheless, Goddard continued development work on the rocket turbine concept, as well as many other propulsion-related projects, until his death in 1945.  Goddard was granted patent number 2,286,908 for his rocket turbine engine concept in June of 1942.

 

Goddard never saw any further development or utilization of his rocket turbine concept beyond what he had conceived of in his lifetime.  Yet today, we must be amazed at how truly visionary Goddard was.  In the decades that have followed, the same motivations for propulsion improvements which drove Dr. Goddard, drive the development of the Air Turbo Rocket which exists today.

Upcoming History of Air Turbo Rocket Development

I’ve been writing up a history of the development of the Air Turbo Rocket, and will be publishing portions as they are completed.

The portions will be published as individual posts consisting of “The Early Years”, covering about 1900 to 1945, “The Middle Years, covering 1945 to 1990, and “Recent Development Work: covering about 1990 to the present time.

I’ve about finished the first portion, and should be posting that later today, or perhaps tomorrow, depending on the work load.

I make no claims as to the thoroughness of my historical accounting, and I readily admit that particular elements of ATR development may well have escaped my scrutiny.  However, after having working with ATR engines for over twenty years, beginning in about 1985, I feel that I have a technical and historical perspective on the development of the ATR that may be of value, and which I would like to share with you, my worthy readers.

Comments and suggestions are always welcome, as long as they are provided in a courteous and respectful manner, and in the spirit of improving the state of the art.  I should add that questions are often the best offering, because they are likely the same questions others may have.

May these, and subsequent posts, provide the motivation for realizing your own propulsion development history.

Rocket City: Business is Booming

Here in Huntsville, we get all sorts of cool stuff coming through town.  Most of the big aerospace contractors have some sort of representation here in town,  and there's the Army’s Redstone Arsenal, and NASA’s Marshall Space Flight Center.

Yesterday, we had an AN-124 transport aircraft fly into town, lugging two centaur upper stages bound for the United Launch Alliance’s Decatur Rocket Plant.  One of these stages will be used as a training tool, the other will go on an Atlas V vehicle.  I drove out to the Huntsville International Airport this morning to check it out.  Here’s a pic from the north end of the runway:

Even from 1.21 miles away (thanks, Google Earth ruler), the AN-124 is big.  The aircraft is parked on the apron in front of Panalpina, an international air freight company with one of its operations here in Huntsville.  The east side of the Huntsville Airport complex is known as the International Intermodal Center, and is a U.S. Customs Port of Entry.  It functions as a distribution hub for international and domestic cargo, and can handle aircraft, trucking, and rail transportation.  Another cool  thing about the Intermodal Center (full disclosure:  I’m getting no remuneration from the Intermodal Center, I just think it's cool), is that it is designated as a Foreign Trade Zone, which means that it is considered to be outside the Customs Territory of the U.S.  This designation means that no duties have to be paid on merchandize that enters the zone and is re-exported, as long as it doesn’t leave the zone and move onto U.S. Customs territory.  And there are other advantages as well.  I bring this up only because I think that it’s a potentially very useful trade advantage for transport businesses, you know, the one’s that transport cargo to and fro.  A clever business person might surely find a way to take advantage of an FTZ, especially businesses associated with the "New Space" industry.  It's just another example of why Huntsville is attractive to aerospace businesses, both commercial and government-based.  Yes, this is a good place to participate in the benefits of a free market economy.

Here’s another shot closer up, from outside the security fence:

The AN-124’s nose hinges up, and it’s landing gear allow the aircraft to kneel, expediting cargo handling.

Here's a view from aft/starboard, which gives a better impression of the size of the An-124:

The An-124's wingspan is about 73.3 m, compared to the 747's wingspan of about 68.5 m.  Here’s a pic from the west side of the Intermodal Zone, where you can see the aircraft in front of the Panalpina facilities:

Ya know, there's nothing too earth-shattering here, but that's sort of the point.  This is exactly the sort of hum-drum, doing-the-business-thing that makes for a vibrant aerospace economy.  It's these activities, and thousands like them, that will create the economic engine capable of expanding our civilization off the planet, and out into space.  In some ways, I think of Huntsville as being like one of those nascent port cities during the age of discovery.  A sort of Lisbon, but with some pretty good barbecue.

And when you're expanding out into space, any city on a planet's surface can become a port city.  You just have to look outwards, outwards towards your exvirons. 

Putting the Test Stand to Work

Got the turbojet on the test stand and got it all hooked up.  Here's the setup:

This particular engine is a bit finicky when it comes to its start sequence.  The ECU (Electronic Control Unit) senses engine speed and  EGT (Exhaust Gas Temp) to determine the engine state.  It then turns off and on the fuel valve, start gas valve, igniter, and electric starter motor, and controls the fuel pump speed to arrive at particular rpm.  The only input required of the operator is the throttle setting.  The throttle (and throttle trim) is used to initiate the start sequence. 

Start sequence went well, and the engine arrived at the idle condition, which is indicated on the monitor with the word "running".  The idle condition condition is set to be 29% full power (as a percent of engine speed).  The monitor indicated the idle engine speed at around 46,000 rpm, which is about right on the money. 
The engine smoothly throttled up to full power, reaching its designed engine speed of about 160,000 rpm.
after several minutes at full power, the engine was throttled to the idle condition.  Given that the fuel suppy was nearing depletion, the engine stop and shutdown sequence was invoked.  For the shutdown, the ECU closes the fuel valve and turns off power to the the fuel pump.  If the EGT is above a certain value (which is was), the starter motor is cylced on and off, supplying cooling air to the engine until the EGT falls below about 100 C.
Although the engine ran well, I had wanted to try out the thrust measurement system.  However, midway through the run, my shop compressor, which I use as an auxillary source of spin-up air if required, kicked out the breaker in the shop.  Since the load cell and DRO where on this circuit, they had no power, and thus I was unable to make any thrust measurements.  Nevertheless, I was pleased that the engine ran quite well.  We'll get it next time.

Test Stand Upgrades: Work in Progress

Bit of a break in postings, still have to earn a living.  But in the interest of "less talk, more action", I thought some of my ongoing work might be of interest.

As previously discussed, I've been upgrading my test stand.  Recently, I finished reinstalling the load cell and its attachment ball joints.  In addition, I refit the ball joint brackets such that they are now electrically insulated from the test stand table and support frame (Note: the test stand “table” refers to the flat top plate of the test stand which is mounted on linear bearings, and can translate forwards and backwards, but not side to side, up or down, or rotate about any axis).  Thus, the load cell itself is electrically isolated from the table and the ground.  While not required for the turbojet and ATR work, I also have some concurrent experiments in which a high-voltage supply was interfering with the load cell readout.  Hopefully, this addition will eliminate that confounder.  Details of the installation look like this:

Here’s a zoom in on the mass calibration scheme:

After completing the load cell reinstallation and table maintenance, it was then necessary to attempt to calibrate the load cell results.  For this calibration, I connected a fixed mass to the table via a pulley.  By varying the fixed mass, and comparing it to the resulting load cell readout, I could start to get a better understanding of what kind of actual thrusts put into the table  would result in measured load cell readings.

Using a water-filled container, different water masses were put in the container.  The container mass was then weighed using a beam balance scale and an electronic scale.  Both beam balance and electronic scales were checked with 100 g calibration masses beforehand, and adjusted accordingly.

The plot below shows the measured results.  In this plot, the measured mass from the electronic scale is shown on the x-axis, against measured masses from the beam balance and load cell shown on the y-axis. The red line is the electronic scale results, i.e the “perfect correlation results”.  The blue points are the beam balance, showing good comparison with the electronic scale, as would be expected.  The beam balance could measure up to about 700g (1.5 lbm), and the electronic scale up to slightly above 2000g (4.4 lbm).  The yellow points are measured load cell results from the different water masses.  The load cell is able to resolve 0.1 lbf.  A linear curve fit is shown as the yellow line, along with the computed linear equation. 

As can be seen, the load cell displays a fairly linear response to the applied loads.  Given the all data passes through zero, the scaling factor for the load cell calibration is thus the slope of the computed linear equation, or about 1.53.  Thus, if the load cell is showing a resultant load measurement of x lbf, then the actual load being applied would be x divided by 1.53.  Given the numerous confounders for making force measurements in this particular configuration, these initial results are encouraging.  

For these results, I was limited to calibration masses of about 2000g, (4.4 lbm). To extend the calibration to higher forces will require a scale that can read larger values.

In addition, the Cooper Load Cell DRO possesses its own internal span and cal pots, so the resultant strain gauge readings can be calibrated appropriately.