Miksi pienhävittäjät eivät onnistu USA:lta ?
- Viestiketjun aloittaja Juke
- Aloitus PVM
Okei Corsair oli kova rassi...miksi yleensä edes hamusivat Bearcattia ?
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edit;
Work on the Grumman G-58 Bearcat began in 1943 with the specifications calling for an aircraft able to operate from the smallest carrier, primarily in the interceptor role. The F6F's Pratt & Whitney R-2800 engine was retained but compared to the Hellcat, the Bearcat was 20% lighter, had a 30% better rate of climb and was 50 mph (80 km/h) faster. To achieve this, range was sacrificed.[7]
An XF8F-1 prototype at the NACA, in 1945.
Compared to the Vought F4U Corsair, the initial F8F-1 Bearcat series was marginally slower but was more maneuverable and climbed more quickly. Its huge 12 ft 4 in Aeroproducts four-bladed propeller required a long landing gear, giving the Bearcat a "nose-up" profile. The hydraulically operated undercarriage used an articulated trunnion which extended the length of the oleo legs when lowered; as the undercarriage retracted the legs were shortened, enabling them to fit into a wheel well which was entirely in the wing. An additional benefit of the inward retracting units was a wide track, which helped counter propeller torque on takeoff and gave the F8F good ground and carrier deck handling.[8] For the first time from the initial version of an all-new airframe design for a production U.S. Navy fighter, a bubble canopy offered 360° visibility.
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edit;
Work on the Grumman G-58 Bearcat began in 1943 with the specifications calling for an aircraft able to operate from the smallest carrier, primarily in the interceptor role. The F6F's Pratt & Whitney R-2800 engine was retained but compared to the Hellcat, the Bearcat was 20% lighter, had a 30% better rate of climb and was 50 mph (80 km/h) faster. To achieve this, range was sacrificed.[7]
An XF8F-1 prototype at the NACA, in 1945.
Compared to the Vought F4U Corsair, the initial F8F-1 Bearcat series was marginally slower but was more maneuverable and climbed more quickly. Its huge 12 ft 4 in Aeroproducts four-bladed propeller required a long landing gear, giving the Bearcat a "nose-up" profile. The hydraulically operated undercarriage used an articulated trunnion which extended the length of the oleo legs when lowered; as the undercarriage retracted the legs were shortened, enabling them to fit into a wheel well which was entirely in the wing. An additional benefit of the inward retracting units was a wide track, which helped counter propeller torque on takeoff and gave the F8F good ground and carrier deck handling.[8] For the first time from the initial version of an all-new airframe design for a production U.S. Navy fighter, a bubble canopy offered 360° visibility.
Viimeksi muokattu:
Tässä ketjussa Orion aka Bill Husa kertoo syitä epäonnistuneisiin skaba ehdotuksiin.
http://www.homebuiltairplanes.com/f...aeronautical-engineering-degree-amateurs.html
Kannattaa lukea ajatuksella...Bill Husa suunnitteli myös aikoinaan COMP AIR 8 koneen joka tuli mäkeen Jämillä taannoin.
Bill itse menehtyi vaikeaan sairauteen parisen vuotta sitten.
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Kyse on siis teollisuuden keskittymisestä avaruus engineeringkiin sen sijaan että keskityttäisiin pienkoneisiin koulutuksessa.
BILLn kommentit;
Well, this would require a fairly substantial presentation to explain some of the issues a bit more deeply but I'll try to do it in somewhat fewer words. First of all, you are not wrong or even off base. Yes, you may be a bit guilty of simplistic generalization but the overall thrust of your supposition is essentially in the ballpark.
I would however like to make one correction: In general, the aeronautical or aerospace professionals rarely have the background to actually design airplanes. The curriculum they go through is largely focused on analysis and the design exercises they do conduct are often limited in scope. This is sort of the nature of the degree since the curriculum is actually focused on aeronautical science, not aircraft design. So, before I get a bit into this, using myself as an example, there needs to be an introduction to one particular term - that of configurator. The following is a brief blurb off of our old web site but i think it can apply here to put the discussion more into the context of airplane design:
The homebuilt industry is full of examples where even the best intentioned programs fail miserably, despite initial claims of revolutionary capabilities. The result is generally a substantial loss of invested funds, an inadequate airplane, useless tooling, a stack of unpaid bills, disillusioned investors and of course, angry depositors. In examining some of these failures of recent years, virtually every downfall can be attributed to a single cause: The lack of an experienced configuration engineer/designer responsible for the program's design tasks, technical guidance and program control.
Some of the most memorable failures of recent memory are the Dream Wings Valkyre, the Prescott Pusher, the Cirrus VK-30, the Omega II and the Questair Venture, among others. And the interesting aspect of this is that this problem is not solely owned by the "Experimental" industry. Large scale, well funded programs also suffer from this phenomenon. Here, recent examples include the AASI Jet Cruiser, the Beech Starship, and the Boeing JSF entry.
In each case, the failure of the program can be directly attributed to a lack of configurational development experience and know-how in those responsible for the program's design tasks. It is therefore of paramount importance to understand what a configuration designer (or configurator) is and what the difference is between that person and an aerodynamicist or aeronautical engineer.
In simplest terms, the configuration design engineer is a generalist. The individual must be well versed in all aspects and requirements of an aircraft development program including aeronautics and flight mechanics, structures and structural design, systems, human factors, operational requirements, materials, manufacturing processes, and at times even marketing issues and customer preferences. In short, the configurator must have the background and practical knowledge needed to design an entire airplane to any set of requirements and performance goals. When required, such as on high end aerospace programs, this individual is backed up by specialists who support his efforts however, it is still the configurator who should be responsible for program's control and direction.
The configurator can be a specialist in one or more areas of design however, his principal strength is the ability to keep all aspects of an airplane in mind throughout the process. This is beneficial in that it allows for program guidance with a minimum amount of entrenchment in any particular level of detail, beyond that which is necessary to achieve the design requirements. Furthermore, this ability often allows the designer to account for variables and design issues up front, thus minimizing redesign and rework cycles, which can be very expensive and time consuming in even the smallest of operations.
A program configurator also has a second, less technical function: that of artist. It is common marketing knowledge that how a product looks has a lot to do with how it will perform in the marketplace - and an airplane is no exception. An experienced configuration designer will understand that the first steps of any airframe development are about 50% artistic. As such, the designer will strive to not only meet the program's technical goals but the aesthetic ones too.
To function as a configurator, it is imperative to not only have the necessary technical education and background, it is also of paramount importance that the individual serves a training or apprenticeship program, where he is taught and/or guided by those with more experience. Configuration design is not a degree offered by any educational institution - it is an intensive effort to gain the necessary amount and variety of experience through program involvement. Today these apprenticeship programs are rare. Very few companies spend the necessary resources training individuals for this discipline. Instead, development programs today tend to be staffed to the hilt with specialists, most of whom rarely have insight into processes beyond their level of expertise. This unfortunately results in poorly run programs that end up with very costly, less than ideal "design by committee" products.
In general aviation, this type of program often results in a poor performer or simply, an unworkable airplane. It is therefore important to have the right individual responsible for the development and program direction so that the aforementioned problems can be circumvented before they become a major roadblock. Failing to do so will unavoidably result in an unsuccessful development.
The paragraphs do tend to be more focused on more commercial programs but the overall theme will still inadvertently apply to anyone looking to design their own.
I'll put the rest into a separate post.
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Like many here, I've wanted to design and fly planes for about as long as I remember. My dad, a long time Mechanical Engineer, had for a long time tried to dissuade me from this route, pretty much hinting that if I ever wanted to eat I should select a more useful degree. His company at the time (Bechtel) hired a fairly substantial number of aeronautical engineers (mid to late seventies), many with Master or Phd degrees, to be basic entry level draftsmen. Not a good sign.
When I got into the university I declared my major immediately (not common then) to be an Aeronautical Engineer. But you don't actually get into the department until your third year and let's face it, in two years stuff happens. I was accepted into the aero department but one quarter into the curriculum the department switched from offering an Aeronautical curriculum to only offering an Aerospace degree. I could still emphasize aeronautics but now I had to add quite a few aerospace courses to graduate. Then one more thing hit - budget cuts. My class went from about 100 students to 50, all a function of grade ranking. At the time I ranked at 52 (long story so I wont bore you) so one quarter later I was out.
Turns out my dad got his way and I was immediately accepted into Mechanical Engineering, and I loved it. Here's a good example why: When I took my first structures class in the aero department the first thing we were introduced to was a tensor. I was never told that Linear Algebra was a prerequisite (had it the next quarter) so my first reaction was a big HUH???!!! And then I spent the rest of the quarter playing catch-up.
But in Mechanical Engineering the first concept you'r introduced to in structures is an "I" beam - now that I could relate to! Furthermore, we were not taught a whole lot of theory of why the beam does what it does (that was earlier in other pre-department classes), instead we were taught how to design with it and other structural types. In other words, the ME curriculum I took was focused largely on practical design and application, even the aero and fluid flow portions.
Now here's the interesting thing - once in the ME department I was able to take all the aero courses I wanted. As such, I sort of made up my own degree (approved by the ME department). It was sort of a BSME with and Aero minor. And when it comes to practical design, I think this was way more useful that the curriculum my university offered. Now, could I design an airplane when I graduated? Not likely - that still took time in the industry, being guided by some very special and influential folks. However, when I saw what my friends in the aero curriculum had as a set of tools when they graduated, I feel I was way ahead when it came to meeting my goals of design.
But at the same time I must also say that my exposure to other universities and their curriculums was (and is) limited. Given the number of folks I've worked with who have had Aero degrees I'd guess that what I saw was typical but I have known one or two who actually did get a better design background than the typical degree would present. So my evaluation of this should be taken as just that: my own experience and opinion.
So why all this? Mainly to say that many of your generalizations above are pretty close to what I've seen and that if we leave out much of the peripheral stuff (some of the humanities requirements and other less than useful electives) one could see some form of educational structure where an actual design (configurator) degree or an informed curriculum for personal use could be presented. But there is sort of a catch - all the background you can get in a class is still not going to make a person a competent designer - there is still that need for some level of practical experience. Yes, part of that could be a portion of the program but it is really the number of programs that you are involved with over time that gains you that functional and practical experience. And it is that that is difficult to package into a class. But maybe that's for a goal of career/work experience.
I think it could be possible to whittle down the practical design issues to a form that the amateur designer could use. But I think it would still be a lot of work since much of this is not going to come from reading a book. It is strictly a doing thing. And of course there is still background that needs to be not only presented but also fully understood. There is nothing more dangerous than a little bit of experience. And I think that's the more difficult part. For instance, no, you really don't need most of the advanced math courses but you really do need to be able to think in actual mathematical terms and have an understanding of the math concepts and their use. You also need a firm background in aero so that the math is actually useful and that you have an innate understanding of how some things affect others. Some of the amateur generalizations that we've seen here are often less than useful and just as often downright wrong.
But how to put this together into an understandable and usable form? I thought about it at times over the years but I'm not sure I ever came up with a clear answer. And most importantly, anyone taking such a curriculum must be made to understand that this would be only for their use - they still would not be fully qualified as having any sort of "expertise" for the mainstream industry.
Anyway, those are my bleary late night thoughts.
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One interesting side note to the above: I got to be the configurator for the Boeing team of the ATF program (I was one of two). While I was designing the configurational variants, the aero types did the support work, backing up what I did and in two instances, it was these aero types that were also designing the cockpit interiors and seating layouts. But they of course thought that they should have been doing the designs but when they suggested that to management they got shot down pretty quickly. The program director flat out told them that their background was insufficient for the configuration work needed on the program.
I got to know one of these guys pretty well subsequently and over the years, he actually did design a few light planes, a couple of which he built. But that work pretty much proved the program managers assertion. None of the planes really worked and one in particular turned out to be a bit on the dangerous side.
This of course should in no way reflect on anyone else nor be a generalization of aero types - it's only presented as one example that demonstrated that configuration design represents more than what a typical aero degree and background encompasses.
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Great discussion. Really interesting to hear the experiences of others who have either followed a similar path to mine, or approached the career from a totally different direction. It seems like the underlying conclusion is that it would a formidable task to put together a more direct curriculum for the amateur designer since the program would have to be simplified to be understandable by those without a technical education, but at the same time still encompass the critical aspects so that the projects that evolved from all the enthusiastic minds would still be functional and at the same time, safe. I think that what seems to be sifting out of all this is that the most reasonable approach is still the self-taught designer, even though that may be doing things the long and hard way, maybe as long and hard as the actual degree.
Just to add to the discussion, I'd like to add a few comments to what ClippedCub wrote earlier. But these are only my observations so should be taken as only that.
Originally Posted by ClippedCub 
In the big companies, no one person designs an airplane. Those days are past. Somebody steps up and says, 'Ok, it'll be a wing with aft tail', and everybody says, 'Ok, thats good' and off all the groups go to make it happen. So in a sense, the new kid can start 'designing' his first airplane from day one, with the senior guys overlooking of course.
I think this is a generalization that really applies only to organizations such as Boeing Commercial, where technology advances in small steps and so to the casual observer, the new airplanes of today look to be not too different from the venerable 707. In this environment the true designer has very little freedom or artistic license - this is the true realm of the aerodynamicist who performs his art in the development of that new optimized high subsonic or transonic wing, but rarely beyond that level. All other design requirements fall out of market studies, niche routes and customer needs. The new kid here can learn this particular process but in my view will never really be a designer beyond the scope of the particular commercial product.
But in the programs I've been involved, it was the one designer that was always the key focus of the program. I've worked for three mainstream organizations including General Dynamics - Convair, HITCO Aerospace and Boeing (Aerospace and Military). In each of these organizations I functioned as the configurator, being solely responsible for the design of the products. Where feasible or necessary, I was supported by aero, signature control, propulsion, materials, weights, etc., but it was still the job of the single configurator to be the focus and driver behind developing the overall design of the product. The fun part of this function was that I got the privilege to work on quite a variety of programs since as has been discussed here, the configurator discipline is no longer widely taught nor do companies train folks for this relatively special position. When I left my last mainstream position, the program was restructured into more the form that ClippedCup describes below, which clearly shoed in the results.
Originally Posted by ClippedCub
The way I see the process working, is that Aero, S&C, Propulsion, and Structures, supply input and algorithms into advanced design's sizing code, and out pops an airplane. We then have meetings so everyone is satisfied with the results, commit to testing, and tweak the design from there. In the case of a fighter configuration, the wave drag, which is a function of area ruling minus the mass flow through the engine/s, defines the body external shape, along with the weapons, fuel, crew,... So essentially, the aero guys define the external shape of the airplane. The designers then try to fit everything inside, and if they can't, we reshape the airplane. Configuration wise, the airplane is a wing with aft tail. Over the years, every configuration under the sun has been investigated, but unless a company is willing to make tremendous risks on a program, the basic configuration's the same.
I think in a way this type of program structure is a sad direction for the industry to head since it leaves little room for creativity. This is essentially a design by committee product that depends more on software and specialized input than true design. While at Boeing Aerospace I was tangentially involved in an attempt to create an in-house expert system whose function was to conceptualize designs for trans-atmospheric vehicle programs - it worked much in the same way as outlined above, but focused at a narrow application. Since the TAV discipline was one of my specialities, I was asked to review the product and the results it spit out. I tested a variety of configurational and mission variables but to me the layouts the program suggested were very generic and of only limited use. Some were downright ridiculous, but the software of course had no way of knowing that. And if an inexperienced designer was by chance an end user, most likely he would not have known that either. In the end, as far as I know, the effort was canceled.
I think that this type of program approach has a tendency to give us the same result as we see today in modern cars. For any subcategory of road vehicle, most of the offerings from all the producers tend to look very alike, with only minor variations. True, much like the "wing with tail in back" idea of airplane design, there is only so many ways to fit four seats between four wheels, but I think there should be some level of creativity allowed to give the consumer more to choose from. The public is often excited by concept cars or some of the work done in the design studios, but rarely does any of that actually reach the street. True, an airplane is not a car but committee products rarely result in real head turners or at times, successful programs.
Back in the late eighties I was an industry consultant to one of the yearly AIAA student competitions. The program the students put together was pretty identical to the structure of multiple inputs described above. And as might be expected, the reams of plots and optimization studies my team spit out resulted in a optimal airplane that looked pretty tame and had numerous shortcomings that would have made it a very efficient but less than useful product. My input gave the students a bit to think about from the standpoint of product presentation and they revised the design into sort of a growth version of the Mini-Imp. It did compromise the optimum performance on a couple of fronts but the result was unique, what I thought was attractive (especially after I saw the other entries), and met all the actual functional goals. And I think I recall it won.
I think the bottom line of all this is that there is still a need for a trained designer who can be responsible for putting together a functional and attractive product. Yes, some areas of the aerospace field must be driven by the more technical and practical, simply due to the nature of the product, but I don't think most others do. As for designing your own, you really have no limits beyond functional safety. Sharpen your pencils and learn to love your erasers (the last was passed on to me by one of my mentors, Mr. Walt Mooney).
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Originally Posted by Monty
Orion, I'm all ears about what I can do to cultivate this mindset, but I'm not sure I can do more than provide the environment for them to grow. What do you think is needed to encourage this skill set?
I wish I had a good answer for you here - I don't. I think the core need to design goes as a function of a person's tastes and drives, a person who's always reaching for something that isn't there yet who feels like it's almost within reach. And I think that type of creativity is a part of the personality. I also think that many younger folks have it but between regimented schooling and an unappreciative work environment, much of that creativity gets squashed. But the need to keep it alive is really up to the person and probably not within anyone else's control.
Years ago I heard a friend of mine's mother (an excellent artist) say that art is something that you cannot teach. You can teach a person to paint but without that innate feeling for the art that person will only be mechanical in the technique, not inspired. And maybe that's the key hint - a person that's inspired (literal translation - God's breath) for a particular art will have more success than one who's simply taught. And I think that's sort of the underlying drive for the need to design, that innate need to create something different or unique that to a point is only within that one person's eye.
I guess the bottom line is simply encouragement. In a work place this may be difficult to do since the goal is product development, not free creativity. But outside of work, be it a class, a club, or whatever, those folks that can do this should simply be encouraged. The interesting thing is that there's not all that many of them and the really creative ones will stand out.
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Actually, spending years associated with one project is pretty rare. Usually the teams that propose, design and prototype a design are all separate staffing divisions, each transitioning as the program evolves through one level of program status and/or funding to the next. Yes, some folks may stay with the program through a few stages to lend the program continuity but often the groups developing each stage are different, especially today where teams of multiple companies eventually produce the final product.
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Originally Posted by ClippedCub
Rutan gets notice because his designs are radical looking airplanes that some think are marvelous. The marvelousness comes from inspiring the imagination and not from any performance are efficiency improvements.
I know this is getting a bit off the thread but I thought I'd throw my 2 cents in here since it has been addressed by others: There are several aspects of Rutan's designs which seem to have held true for some time. The key of these is that his work is unique and yes, to a point inspirational in that potential designers are shown, by example, that the products they design don't all have to look like Cessnas or Cherokees. For me the real head turner of the day was the VariViggen. Before I entered the university and was still a machinist for Boeing I ran across a book that featured the design - for the day, it really looked cool. It even made me watch the horrid movie that featured it several times (Death Race 2000) just for the flight scenes.
But at school and after, two continuing themes run through much of that work: First, the designs are a departure from the norm and it is that uniqueness that holds peoples attention more so than any aerodynamic benefit or improvement. The major contribution to any increase in performance in craft like the Ezes is not the configuration but simply the fact that they are very small. But uniqueness has its place, especially if it can gather a following or inspire a market. Which brings me to the second theme and that is simply that despite popularity, the vast majority of Rutan's work has been pretty much a marketing and/or technical failure. For all the designs that have come from his imagination, the successes have been almost non existent. True, the company is doing seemingly well but that's due to more conventional work - none of the unique products folks usually discuss have actually entered any form of production, outside of the Ezes and the Starship, although the latter was predictably also a failure.
But credit has to be given since the variety of configurational presentations show his willingness to take a chance and to show that with a little bit of imagination, we can strive to be better at what we do.
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Täällä Bill Husa vielä edelleen mainitaan; http://www.oriontechnologies.net/orion/Principals.html
http://www.homebuiltairplanes.com/f...aeronautical-engineering-degree-amateurs.html
Kannattaa lukea ajatuksella...Bill Husa suunnitteli myös aikoinaan COMP AIR 8 koneen joka tuli mäkeen Jämillä taannoin.
Bill itse menehtyi vaikeaan sairauteen parisen vuotta sitten.
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Kyse on siis teollisuuden keskittymisestä avaruus engineeringkiin sen sijaan että keskityttäisiin pienkoneisiin koulutuksessa.
BILLn kommentit;
Well, this would require a fairly substantial presentation to explain some of the issues a bit more deeply but I'll try to do it in somewhat fewer words. First of all, you are not wrong or even off base. Yes, you may be a bit guilty of simplistic generalization but the overall thrust of your supposition is essentially in the ballpark.
I would however like to make one correction: In general, the aeronautical or aerospace professionals rarely have the background to actually design airplanes. The curriculum they go through is largely focused on analysis and the design exercises they do conduct are often limited in scope. This is sort of the nature of the degree since the curriculum is actually focused on aeronautical science, not aircraft design. So, before I get a bit into this, using myself as an example, there needs to be an introduction to one particular term - that of configurator. The following is a brief blurb off of our old web site but i think it can apply here to put the discussion more into the context of airplane design:
The homebuilt industry is full of examples where even the best intentioned programs fail miserably, despite initial claims of revolutionary capabilities. The result is generally a substantial loss of invested funds, an inadequate airplane, useless tooling, a stack of unpaid bills, disillusioned investors and of course, angry depositors. In examining some of these failures of recent years, virtually every downfall can be attributed to a single cause: The lack of an experienced configuration engineer/designer responsible for the program's design tasks, technical guidance and program control.
Some of the most memorable failures of recent memory are the Dream Wings Valkyre, the Prescott Pusher, the Cirrus VK-30, the Omega II and the Questair Venture, among others. And the interesting aspect of this is that this problem is not solely owned by the "Experimental" industry. Large scale, well funded programs also suffer from this phenomenon. Here, recent examples include the AASI Jet Cruiser, the Beech Starship, and the Boeing JSF entry.
In each case, the failure of the program can be directly attributed to a lack of configurational development experience and know-how in those responsible for the program's design tasks. It is therefore of paramount importance to understand what a configuration designer (or configurator) is and what the difference is between that person and an aerodynamicist or aeronautical engineer.
In simplest terms, the configuration design engineer is a generalist. The individual must be well versed in all aspects and requirements of an aircraft development program including aeronautics and flight mechanics, structures and structural design, systems, human factors, operational requirements, materials, manufacturing processes, and at times even marketing issues and customer preferences. In short, the configurator must have the background and practical knowledge needed to design an entire airplane to any set of requirements and performance goals. When required, such as on high end aerospace programs, this individual is backed up by specialists who support his efforts however, it is still the configurator who should be responsible for program's control and direction.
The configurator can be a specialist in one or more areas of design however, his principal strength is the ability to keep all aspects of an airplane in mind throughout the process. This is beneficial in that it allows for program guidance with a minimum amount of entrenchment in any particular level of detail, beyond that which is necessary to achieve the design requirements. Furthermore, this ability often allows the designer to account for variables and design issues up front, thus minimizing redesign and rework cycles, which can be very expensive and time consuming in even the smallest of operations.
A program configurator also has a second, less technical function: that of artist. It is common marketing knowledge that how a product looks has a lot to do with how it will perform in the marketplace - and an airplane is no exception. An experienced configuration designer will understand that the first steps of any airframe development are about 50% artistic. As such, the designer will strive to not only meet the program's technical goals but the aesthetic ones too.
To function as a configurator, it is imperative to not only have the necessary technical education and background, it is also of paramount importance that the individual serves a training or apprenticeship program, where he is taught and/or guided by those with more experience. Configuration design is not a degree offered by any educational institution - it is an intensive effort to gain the necessary amount and variety of experience through program involvement. Today these apprenticeship programs are rare. Very few companies spend the necessary resources training individuals for this discipline. Instead, development programs today tend to be staffed to the hilt with specialists, most of whom rarely have insight into processes beyond their level of expertise. This unfortunately results in poorly run programs that end up with very costly, less than ideal "design by committee" products.
In general aviation, this type of program often results in a poor performer or simply, an unworkable airplane. It is therefore important to have the right individual responsible for the development and program direction so that the aforementioned problems can be circumvented before they become a major roadblock. Failing to do so will unavoidably result in an unsuccessful development.
The paragraphs do tend to be more focused on more commercial programs but the overall theme will still inadvertently apply to anyone looking to design their own.
I'll put the rest into a separate post.
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Like many here, I've wanted to design and fly planes for about as long as I remember. My dad, a long time Mechanical Engineer, had for a long time tried to dissuade me from this route, pretty much hinting that if I ever wanted to eat I should select a more useful degree. His company at the time (Bechtel) hired a fairly substantial number of aeronautical engineers (mid to late seventies), many with Master or Phd degrees, to be basic entry level draftsmen. Not a good sign.
When I got into the university I declared my major immediately (not common then) to be an Aeronautical Engineer. But you don't actually get into the department until your third year and let's face it, in two years stuff happens. I was accepted into the aero department but one quarter into the curriculum the department switched from offering an Aeronautical curriculum to only offering an Aerospace degree. I could still emphasize aeronautics but now I had to add quite a few aerospace courses to graduate. Then one more thing hit - budget cuts. My class went from about 100 students to 50, all a function of grade ranking. At the time I ranked at 52 (long story so I wont bore you) so one quarter later I was out.
Turns out my dad got his way and I was immediately accepted into Mechanical Engineering, and I loved it. Here's a good example why: When I took my first structures class in the aero department the first thing we were introduced to was a tensor. I was never told that Linear Algebra was a prerequisite (had it the next quarter) so my first reaction was a big HUH???!!! And then I spent the rest of the quarter playing catch-up.
But in Mechanical Engineering the first concept you'r introduced to in structures is an "I" beam - now that I could relate to! Furthermore, we were not taught a whole lot of theory of why the beam does what it does (that was earlier in other pre-department classes), instead we were taught how to design with it and other structural types. In other words, the ME curriculum I took was focused largely on practical design and application, even the aero and fluid flow portions.
Now here's the interesting thing - once in the ME department I was able to take all the aero courses I wanted. As such, I sort of made up my own degree (approved by the ME department). It was sort of a BSME with and Aero minor. And when it comes to practical design, I think this was way more useful that the curriculum my university offered. Now, could I design an airplane when I graduated? Not likely - that still took time in the industry, being guided by some very special and influential folks. However, when I saw what my friends in the aero curriculum had as a set of tools when they graduated, I feel I was way ahead when it came to meeting my goals of design.
But at the same time I must also say that my exposure to other universities and their curriculums was (and is) limited. Given the number of folks I've worked with who have had Aero degrees I'd guess that what I saw was typical but I have known one or two who actually did get a better design background than the typical degree would present. So my evaluation of this should be taken as just that: my own experience and opinion.
So why all this? Mainly to say that many of your generalizations above are pretty close to what I've seen and that if we leave out much of the peripheral stuff (some of the humanities requirements and other less than useful electives) one could see some form of educational structure where an actual design (configurator) degree or an informed curriculum for personal use could be presented. But there is sort of a catch - all the background you can get in a class is still not going to make a person a competent designer - there is still that need for some level of practical experience. Yes, part of that could be a portion of the program but it is really the number of programs that you are involved with over time that gains you that functional and practical experience. And it is that that is difficult to package into a class. But maybe that's for a goal of career/work experience.
I think it could be possible to whittle down the practical design issues to a form that the amateur designer could use. But I think it would still be a lot of work since much of this is not going to come from reading a book. It is strictly a doing thing. And of course there is still background that needs to be not only presented but also fully understood. There is nothing more dangerous than a little bit of experience. And I think that's the more difficult part. For instance, no, you really don't need most of the advanced math courses but you really do need to be able to think in actual mathematical terms and have an understanding of the math concepts and their use. You also need a firm background in aero so that the math is actually useful and that you have an innate understanding of how some things affect others. Some of the amateur generalizations that we've seen here are often less than useful and just as often downright wrong.
But how to put this together into an understandable and usable form? I thought about it at times over the years but I'm not sure I ever came up with a clear answer. And most importantly, anyone taking such a curriculum must be made to understand that this would be only for their use - they still would not be fully qualified as having any sort of "expertise" for the mainstream industry.
Anyway, those are my bleary late night thoughts.
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One interesting side note to the above: I got to be the configurator for the Boeing team of the ATF program (I was one of two). While I was designing the configurational variants, the aero types did the support work, backing up what I did and in two instances, it was these aero types that were also designing the cockpit interiors and seating layouts. But they of course thought that they should have been doing the designs but when they suggested that to management they got shot down pretty quickly. The program director flat out told them that their background was insufficient for the configuration work needed on the program.
I got to know one of these guys pretty well subsequently and over the years, he actually did design a few light planes, a couple of which he built. But that work pretty much proved the program managers assertion. None of the planes really worked and one in particular turned out to be a bit on the dangerous side.
This of course should in no way reflect on anyone else nor be a generalization of aero types - it's only presented as one example that demonstrated that configuration design represents more than what a typical aero degree and background encompasses.
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Great discussion. Really interesting to hear the experiences of others who have either followed a similar path to mine, or approached the career from a totally different direction. It seems like the underlying conclusion is that it would a formidable task to put together a more direct curriculum for the amateur designer since the program would have to be simplified to be understandable by those without a technical education, but at the same time still encompass the critical aspects so that the projects that evolved from all the enthusiastic minds would still be functional and at the same time, safe. I think that what seems to be sifting out of all this is that the most reasonable approach is still the self-taught designer, even though that may be doing things the long and hard way, maybe as long and hard as the actual degree.
Just to add to the discussion, I'd like to add a few comments to what ClippedCub wrote earlier. But these are only my observations so should be taken as only that.
In the big companies, no one person designs an airplane. Those days are past. Somebody steps up and says, 'Ok, it'll be a wing with aft tail', and everybody says, 'Ok, thats good' and off all the groups go to make it happen. So in a sense, the new kid can start 'designing' his first airplane from day one, with the senior guys overlooking of course.
I think this is a generalization that really applies only to organizations such as Boeing Commercial, where technology advances in small steps and so to the casual observer, the new airplanes of today look to be not too different from the venerable 707. In this environment the true designer has very little freedom or artistic license - this is the true realm of the aerodynamicist who performs his art in the development of that new optimized high subsonic or transonic wing, but rarely beyond that level. All other design requirements fall out of market studies, niche routes and customer needs. The new kid here can learn this particular process but in my view will never really be a designer beyond the scope of the particular commercial product.
But in the programs I've been involved, it was the one designer that was always the key focus of the program. I've worked for three mainstream organizations including General Dynamics - Convair, HITCO Aerospace and Boeing (Aerospace and Military). In each of these organizations I functioned as the configurator, being solely responsible for the design of the products. Where feasible or necessary, I was supported by aero, signature control, propulsion, materials, weights, etc., but it was still the job of the single configurator to be the focus and driver behind developing the overall design of the product. The fun part of this function was that I got the privilege to work on quite a variety of programs since as has been discussed here, the configurator discipline is no longer widely taught nor do companies train folks for this relatively special position. When I left my last mainstream position, the program was restructured into more the form that ClippedCup describes below, which clearly shoed in the results.
The way I see the process working, is that Aero, S&C, Propulsion, and Structures, supply input and algorithms into advanced design's sizing code, and out pops an airplane. We then have meetings so everyone is satisfied with the results, commit to testing, and tweak the design from there. In the case of a fighter configuration, the wave drag, which is a function of area ruling minus the mass flow through the engine/s, defines the body external shape, along with the weapons, fuel, crew,... So essentially, the aero guys define the external shape of the airplane. The designers then try to fit everything inside, and if they can't, we reshape the airplane. Configuration wise, the airplane is a wing with aft tail. Over the years, every configuration under the sun has been investigated, but unless a company is willing to make tremendous risks on a program, the basic configuration's the same.
I think in a way this type of program structure is a sad direction for the industry to head since it leaves little room for creativity. This is essentially a design by committee product that depends more on software and specialized input than true design. While at Boeing Aerospace I was tangentially involved in an attempt to create an in-house expert system whose function was to conceptualize designs for trans-atmospheric vehicle programs - it worked much in the same way as outlined above, but focused at a narrow application. Since the TAV discipline was one of my specialities, I was asked to review the product and the results it spit out. I tested a variety of configurational and mission variables but to me the layouts the program suggested were very generic and of only limited use. Some were downright ridiculous, but the software of course had no way of knowing that. And if an inexperienced designer was by chance an end user, most likely he would not have known that either. In the end, as far as I know, the effort was canceled.
I think that this type of program approach has a tendency to give us the same result as we see today in modern cars. For any subcategory of road vehicle, most of the offerings from all the producers tend to look very alike, with only minor variations. True, much like the "wing with tail in back" idea of airplane design, there is only so many ways to fit four seats between four wheels, but I think there should be some level of creativity allowed to give the consumer more to choose from. The public is often excited by concept cars or some of the work done in the design studios, but rarely does any of that actually reach the street. True, an airplane is not a car but committee products rarely result in real head turners or at times, successful programs.
Back in the late eighties I was an industry consultant to one of the yearly AIAA student competitions. The program the students put together was pretty identical to the structure of multiple inputs described above. And as might be expected, the reams of plots and optimization studies my team spit out resulted in a optimal airplane that looked pretty tame and had numerous shortcomings that would have made it a very efficient but less than useful product. My input gave the students a bit to think about from the standpoint of product presentation and they revised the design into sort of a growth version of the Mini-Imp. It did compromise the optimum performance on a couple of fronts but the result was unique, what I thought was attractive (especially after I saw the other entries), and met all the actual functional goals. And I think I recall it won.
I think the bottom line of all this is that there is still a need for a trained designer who can be responsible for putting together a functional and attractive product. Yes, some areas of the aerospace field must be driven by the more technical and practical, simply due to the nature of the product, but I don't think most others do. As for designing your own, you really have no limits beyond functional safety. Sharpen your pencils and learn to love your erasers (the last was passed on to me by one of my mentors, Mr. Walt Mooney).
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Orion, I'm all ears about what I can do to cultivate this mindset, but I'm not sure I can do more than provide the environment for them to grow. What do you think is needed to encourage this skill set?
I wish I had a good answer for you here - I don't. I think the core need to design goes as a function of a person's tastes and drives, a person who's always reaching for something that isn't there yet who feels like it's almost within reach. And I think that type of creativity is a part of the personality. I also think that many younger folks have it but between regimented schooling and an unappreciative work environment, much of that creativity gets squashed. But the need to keep it alive is really up to the person and probably not within anyone else's control.
Years ago I heard a friend of mine's mother (an excellent artist) say that art is something that you cannot teach. You can teach a person to paint but without that innate feeling for the art that person will only be mechanical in the technique, not inspired. And maybe that's the key hint - a person that's inspired (literal translation - God's breath) for a particular art will have more success than one who's simply taught. And I think that's sort of the underlying drive for the need to design, that innate need to create something different or unique that to a point is only within that one person's eye.
I guess the bottom line is simply encouragement. In a work place this may be difficult to do since the goal is product development, not free creativity. But outside of work, be it a class, a club, or whatever, those folks that can do this should simply be encouraged. The interesting thing is that there's not all that many of them and the really creative ones will stand out.
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Actually, spending years associated with one project is pretty rare. Usually the teams that propose, design and prototype a design are all separate staffing divisions, each transitioning as the program evolves through one level of program status and/or funding to the next. Yes, some folks may stay with the program through a few stages to lend the program continuity but often the groups developing each stage are different, especially today where teams of multiple companies eventually produce the final product.
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Rutan gets notice because his designs are radical looking airplanes that some think are marvelous. The marvelousness comes from inspiring the imagination and not from any performance are efficiency improvements.
I know this is getting a bit off the thread but I thought I'd throw my 2 cents in here since it has been addressed by others: There are several aspects of Rutan's designs which seem to have held true for some time. The key of these is that his work is unique and yes, to a point inspirational in that potential designers are shown, by example, that the products they design don't all have to look like Cessnas or Cherokees. For me the real head turner of the day was the VariViggen. Before I entered the university and was still a machinist for Boeing I ran across a book that featured the design - for the day, it really looked cool. It even made me watch the horrid movie that featured it several times (Death Race 2000) just for the flight scenes.
But at school and after, two continuing themes run through much of that work: First, the designs are a departure from the norm and it is that uniqueness that holds peoples attention more so than any aerodynamic benefit or improvement. The major contribution to any increase in performance in craft like the Ezes is not the configuration but simply the fact that they are very small. But uniqueness has its place, especially if it can gather a following or inspire a market. Which brings me to the second theme and that is simply that despite popularity, the vast majority of Rutan's work has been pretty much a marketing and/or technical failure. For all the designs that have come from his imagination, the successes have been almost non existent. True, the company is doing seemingly well but that's due to more conventional work - none of the unique products folks usually discuss have actually entered any form of production, outside of the Ezes and the Starship, although the latter was predictably also a failure.
But credit has to be given since the variety of configurational presentations show his willingness to take a chance and to show that with a little bit of imagination, we can strive to be better at what we do.
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Täällä Bill Husa vielä edelleen mainitaan; http://www.oriontechnologies.net/orion/Principals.html
Viimeksi muokattu:
mielenkiintoinen viesti lentokoneen suunnittelusta! En jaksanut lukea aivan kokonaan kerralla, luen myöhemmin loppuun.
Katsoin youtubesta haastattelun jossa haastateltiin SOG knives- yrityksen perustajaa ja ensimmäistä toimitusjohtajaa. https://www.sogknives.com/
Kyseinen herra oli saanut omasta mielestään monipuolisen koulutuksen taiteellisella ja teollinen muotoilu puolella, ja hän oli itseasiassa aikanaan 1990- luvulla toiminut B2 Spirit- pommittajan suunniittelutiimissä mukana. Hänellä siis oli tuolloin "top secret" luokitus.
Eräänä päivänä töissä, hän huomasi jotan outoa B2 Spirit pommikoneen pienoismallissa. Pienoismallin toinen siipi oli liian pitkä. Siivet olivat niinsanotusti "epäsymmetriset".
Hän oli tuolloin vasta harjoittelijana töissä tuossa projektissa. Hän toi asian insinöörien ja projektin johtajan huomioon. Siipi todella oli liian pitkä pienoismallissa. Kukaan ei tiennyt syytä miksi, mutta mittanauhalla mittaamalla selvitys saatiin. Siipi todella oli liian pitkä.
Koneen teknisiä piirustuksia jouduttiin tarkastamaan uudelleen, ja hyvällä syyllä....
Katsoin youtubesta haastattelun jossa haastateltiin SOG knives- yrityksen perustajaa ja ensimmäistä toimitusjohtajaa. https://www.sogknives.com/
Kyseinen herra oli saanut omasta mielestään monipuolisen koulutuksen taiteellisella ja teollinen muotoilu puolella, ja hän oli itseasiassa aikanaan 1990- luvulla toiminut B2 Spirit- pommittajan suunniittelutiimissä mukana. Hänellä siis oli tuolloin "top secret" luokitus.
Eräänä päivänä töissä, hän huomasi jotan outoa B2 Spirit pommikoneen pienoismallissa. Pienoismallin toinen siipi oli liian pitkä. Siivet olivat niinsanotusti "epäsymmetriset".
Hän oli tuolloin vasta harjoittelijana töissä tuossa projektissa. Hän toi asian insinöörien ja projektin johtajan huomioon. Siipi todella oli liian pitkä pienoismallissa. Kukaan ei tiennyt syytä miksi, mutta mittanauhalla mittaamalla selvitys saatiin. Siipi todella oli liian pitkä.
Koneen teknisiä piirustuksia jouduttiin tarkastamaan uudelleen, ja hyvällä syyllä....
Mikoyan
Ylipäällikkö
Saab käyttää amerikkalaisten valmistamia moottoreita ja Gripenin runkosuunnittelukin lienee pääosin amerikkalaisten käsialaa. En näe syytä miksi jenkit ylipäätään ostaisivat oman tuotteensa rapakon takaa. Samaantapaan voisivat ottaa Hornetin moottorin ja avioniikan ja kyhätä rungon sen ympärille ja paketti on valmis tuotantoon.
TT
Eversti
Älä hyvä ihminen laita noin syvällä rintaäänellä jyrkkiä väitteitä jos ei sulla kuitenkaan ole varmaa tietoa. Volvo Flygmotorilla (nykyään SAAB/BAe?) on ollut GE:n suihkumoottoreihin valmistuslisenssi jo kai Tunnanin ajoista saakka. Muistaakseni jo Drakenin moottoriin suunniteltiin ja lisättiin jälkipoltin Ruotsissa joten siinäkin on svenssonien omaa panosta enemmän kuin pelkkä osien sorvaus ja kasaus.
Gripenin rungon ja järjestelmien suunnittelu (mm. natolinkkiä parempi tietovuojärjestelmä) lienee kuitenkin hyvin ruotsalaista käsialaa, tosin varmasti rapakon takaa on saatu teknologista avustusta kuten täälläkin on monessa ilmailuketjussa mainittu. Eihän jenkeillä ole ollut samanlaista STOL-orientoitunutta suunnittelua juuri muualla kuin Mariinien brittiperäisissä Harriereissa. Tuskin ovat kovin pitkälle salaisissa verstaissa kehittäneet sellaista mitä eivät ole tarvinneet ja käyttäneet?
En ihmettelisi vaikka USA ostaisi trainerin muualta. Siis jos Lämäri tai Bouing ei innostu aiheesta. Ei sinänsä mitään strategista merkitystä mikä vehje kunhan sopii hommaan ja hintalappu ei hirvitä. Toisaalta vaikea nähdä Ruotsi hyvänä vastakauppakumppanina. Saapas nähdä.
Samovarius
Ylipäällikkö
Amerikkalaiset ovat valmistaneet sangen vähän pienhävittäjiä, koska heillä ei ole sellaisille tarvetta. Pitkän toimintasäteen saatto-, ilmaherruus-, ja laivastohävittäjät ovat käytännön sanelemina isompia ja kalliimpia. Tosin aivan tuntematon käsite ei sielläkään ole: esmes A-4 Skyhawk oli niin pieni, ettei se tarvinnut tukialuksilla edes taittuvia siipiä. Koneen elinkaari myös oli melko pitkä, eli kyseessä ei ollut pelkkä kuriositeetti. A-37 Dragonfly oli konseptina hyvin samankaltainen, kevyt maataistelukone. Sitten on vientiin tarkoitettu F-5 ja Hornetista kaavailtu denavalisoitu kevytkävittäjä tietysti. Point defence fighter lienee konseptina suht lähellä kevythävittäjää, tosin F-102/106 oli muistaakseni aika mutkikkailla järjestelmillä varustettu kone. Sama pätee F-104:ään, josta tosin tuli suosittu vientituote, ja näki USA:ssa suht vähän käyttöä. Ehkä tähän vaikutti Vietnamin sodan luonne, jonne Starfighter ei soveltunut?
USAssa ilmeisesti sisäpoliittisista ja tätä kautta juridisista syistä harvoin hankitaan suoraan ulkomaista kalustoa. Sen sijaan tämä konsepti, missä valmista tuotetta tehdään USA:ssa lisenssillä tai bulvaanin tai tytäryhtiön välityksellä on yleinen. Listalta voinee mainita ainakin asevoimien palveluspistoolin ja laivaston suihkuharjoituskoneen.
F4U Corsairista sen verran, että kone oli pitkän nokkansa ja siiven sakkaustaipumuksen takia vaikea laskeuduttava tukialuksille. Britit hioivat tätä tekniikkaa lopulta riittävästi, eli laskuun tultiin pitkässä ja loivassa kaarrossa ja oikaistiin vasta aivan lopussa. Vaikka se olikin suunniteltu periaatteella suurimman mahdollisen moottorin ympärille mahdollisimman pieni kone, en lähtisi väittämään Corsairia mitenkään kevythävittäjäksi. Ottihan se aikanaan vaikuttavan yli tonnin pommikuorman ja koneesta oli myös tutkalla varustettu yöhävittäjämalli.
USAssa ilmeisesti sisäpoliittisista ja tätä kautta juridisista syistä harvoin hankitaan suoraan ulkomaista kalustoa. Sen sijaan tämä konsepti, missä valmista tuotetta tehdään USA:ssa lisenssillä tai bulvaanin tai tytäryhtiön välityksellä on yleinen. Listalta voinee mainita ainakin asevoimien palveluspistoolin ja laivaston suihkuharjoituskoneen.
F4U Corsairista sen verran, että kone oli pitkän nokkansa ja siiven sakkaustaipumuksen takia vaikea laskeuduttava tukialuksille. Britit hioivat tätä tekniikkaa lopulta riittävästi, eli laskuun tultiin pitkässä ja loivassa kaarrossa ja oikaistiin vasta aivan lopussa. Vaikka se olikin suunniteltu periaatteella suurimman mahdollisen moottorin ympärille mahdollisimman pieni kone, en lähtisi väittämään Corsairia mitenkään kevythävittäjäksi. Ottihan se aikanaan vaikuttavan yli tonnin pommikuorman ja koneesta oli myös tutkalla varustettu yöhävittäjämalli.
Joo, olisihan se hienoa jos olisi ollut uutta asiaa aiheesta. Mutta kommentoitiin vain ikivanhaa heittoa.Kerrankin joku etsii sopivan vanhan ketjun eikä avaa uutta rinnalle. Respectl
Enkä minä ottanut niinkään asiasisältöön kantaa. Muistelen vain monen saaneen yhteisen matkamme varrella moitteita kun eivät ole vaivautuneet jatkamaan sopivia vanhoja ketjuja.
Leaderwolf
Respected Leader
Miksi pienhävittäjä ei sovellu Suomelle? Ei mahdu tarpeeksi pudotusmerkkejä kuomun alle.
Tämä on tosiaan koettu isoksi ongelmaksi
Huhta
Greatest Leader
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