I think that SJ's problem with 7" ipads will turn out to be a red herring.
Yeah, because the ultra-mobile market is extremely popular... just look how many UMPC's have been sold since they debuted compared to say, netbooks.
Sorry, but Steve Jobs is correct. There is a fine line between mobility and practicality. If you're on the go, most people will want to stick with something that they can carry on them at all times -- fits in their pocket. If you're not on the go, then most people will want something that is easier on the eyes for longer, more comfortable use.
UMPC's failed because they were too small to use for any extended amount of time to get any real work done.
7 Inch devices are the key to most of Apple's competitors. The reason is simple, Apple's iPad doesn't encroach on it's smaller iOS devices. Most of Apple's competitors can't compete with the smaller iOS devices. That means that if everyone else sticks to 7 inch devices, they can clean up sales from both ends of Apple products.
Unfortunately, I love my Mac too much to give it an android based companion. /bummer
You have to consider where the respective manufacturers want to end up. Apple has always been about being perceived as a premium option, preferring to let others pursue the bargain-basement segment.
The reason that I believe competitors are opting for a 7" form factor is that a few years from now, as the tablet market matures, they're going to want to be the ones selling $200 tablets. In contrast, Apple is perfectly happy to be the one selling $400 tablets. Whatever disadvantages there are to using the larger screen will be addressed in time as technology improves. Battery life, weight, storage capacity, processing power. All of those will improve and as they do it becomes easier for Apple to increase the iPad's screen resolution.
While Apple refines its 9.7" tablet, the competition will be busy producing progressively cheaper 7" devices. Probably, Apple will be one step ahead and as a result, consumers will be willing to pay more for Apple's offerings. Perceived quality will be helped by having a device with a larger screen.
Once I checked out an iPad on display by a local retailer my impression is of a device that does not seem at all too large. With a weight reduction that we all know is coming, it will be a very appealing form factor. If you want cheap, everybody else will have that covered in spades.That's not Apple's thing. Never has been, probably never will be.
I asked this very question when I was considering buying/building a carbon fiber Lancair aircraft back in 2001. The FAA approved the Lancair Columbia, but took an inordinate amount of time trying to come up with formulas that would explain precise breaking points (there is precious little in the literature or experience). The FAA likes metallic skins for wings, because you have to prove that the wing will withstand about 150% or so of probable maximum stress before breaking. Metal breaks in predictable fashion, whereas carbon fiber does not. In fact, the FAA just about gave up on trying to get the Lancair wing to break, which created a dilemma.
Anyhow, carbon fiber is more rigid, but may not bend as much before breaking, but can usually take much more force before shattering (so I have been led to believe).
I opted for an aluminum plane because I wanted a plane that was easier to repair, and one which resisted outside weathering better (carbon fiber does not hold up very well compared to aluminum).
Anyhow, a carbon-fiber case would certainly be lightweight, and could be designed to be very inflexible to resist twisting.
Whatever happened to all the ceramic uses that everyone was touting a few years back? Maybe carbon fiber is the way to go now, but I would still think the very thin liquid metal would make sense, as long as it was made non-conductive or insulated. Carbon fiber and ceramic can be made very insular, so I'm told, which may be a factor, and the ability to wick heat away from the batteries is also a factor.
If you talk to old hands in aviation, they will say that they don't trust carbon fiber airframes, but this is more a function of the slowness of aviation to accept new technologies than anything else. They just don't have the same long experience with the materials. This seems ironic to me, given the inherent problems with aluminum airframes, and all the difficult to find corrosion that can cause them to be expensive to maintain, if not fail outright. But it's the devil they know. Not sure what happened in the Lancair case, but lots of carbon fiber airframes have been certified by the FAA, so I don't think it's a fundamental problem. Lancair was one of the first, so perhaps that's why.
Boats, road cars, all formula 1 racing cars (which have tremendous impact strength) many different aircraft, both military and non military, and even other computer devices- Sony come to mind. the only thing they can be patenting is some specific manufacturing or design technique, not the use of the material. I would love them to use cfrp for this and the Macbook Air. It's light, won't dent like aluminium and won't dent or scratch other things. And when the device finally dies, it will make a lovely high tech tea tray.
Actually many of the modern ways of producing carbon fibre come from processes invented by a New Zealander by the name of John Britten of the Britten motorcycle fame.
He wanted a lightweight material that was strong enough to essentially become the frame and thus hold the weight of an engine. Not only that but actual parts of the engine were made in carborn fibre. While carbon fibre techniques existed none of them produced the product he wanted and needed so he developed his own. Not bad for a guy who did all of this in the back of his shed.
Can someone explain to me exactly how carbon fiber breaks. I understand the concept that if you put stress on an object made out of the material in the same direction as the seams then it will break. What I don't get is how my tripods (I am a t producer) made out of carbon fiber have never broken
Exactly, carbon fiber is used in custom car creation for a reason. It's light-weight AND strong.
@"Apple Chief Executive Steve Jobs quieted those rumors < 7-inch iPad> in October, when he said a 7-inch tablet is too small for most consumers."
I don't suppose there have been any instances in the past of SJ intentionally leading the hounds off the scent?
Now let me count 'em....
While I agree that Steve is known for misdirection, in this case he's right. 7" is too small for a "tablet" while not really being any more portable than an iPad. You have to go smaller than 6" before portability improves significantly.
Once you're down to 6" you're into a whole new class of information appliance more akin to a big smartphone than a tablet. It happens to be the size that most interests me, but the one that no company is currently producing (the Dell Streak with it's outdated hardware and ancient version of Android really doesn't count).
Don't leave your iPad on the roof of your car and then drive off... My father-in-law figured this rule out the hard way.
His iPad was a crinkly sheet of metal and plastic by the end....
My girlfriend did that with her phone. It actually stayed on top of the car for a pretty good distance. We found it over half a mile away from the house in a pile of leaves by the curve. Would have never been able to find it if we didn't hear it ring.
I like carbon fiber. I don't see the batteries as being a surmountable problem. They are already based on lithium, the lightest metal.
Speaking of which, I wonder why Apple don't look at applying the unibody idea to magnesium instead of Aluminium. There is a glut at the moment and it's cheap. It's Lighter than Al and stiff. I know it is reactive as all hell, but maybe they could coat it with Titanium nitride or some other surface treatment to get round the problem.
The problemis in production, many a CNC mill has meant its death in a magnesium fire. The material does produce great light weight parts but is it worth the trouble.
Besides Apple could put an environmental spin on carbon fiber. My biggest concern would be the expense of the housing as it is likely to be more expensive than the CNC machined Aluminum. O
Airplanes, too. Anywhere lightness and strength are at a premium is a potential application for carbon fiber. Speaking of airplanes, they are most often constructed with a rigid skin over supporting spars and ribs. This method of construction, known as semi-monocoque, has been around for nearly 100 years.
Wow, 100 years? carbon fiber as a construction material? the same lineage as the carbon fiber used for cars, tripods, boats, planes, etc.?
References please.
As to the type of carbon fibers as a ligt construction material as we know today, it is more ca 1950's
This should not be confused with artificial fibers, with have carbon in them of course, or were derived initially from natural materials with carbon in them
with some dating back about a century ago (for the artificial fibers), but not really the same as the synthetic fibers that came in the mid 20th century.
There were indeed the first carbon fibers, based on the inventions of Edison, but those carbon fibers were not exactly the same technology as we know the carbon fibers used in the construction of the rigid, durable and lightweight material technologies used in tripods, cars, planes, boats, etc.
Sure one could claim the historical evolution of the technology from those early carbon fibers, but then Nature has "accidentally created polymeric carbons, even before man ever was in this world.
Boats are mostly made from fiberglass. An entire board hull made from carbon fiber would cost several times as much.
I think he's referring to high end racing yachts analogous to the Formula I racing cars. I believe America's Cup yachts all have carbon fiber incorporated in their hulls.
Wow, 100 years? carbon fiber as a construction material? the same lineage as the carbon fiber used for cars, tripods, boats, planes, etc.?
References please.
Read more carefully. He said,
" . . . constructed with a rigid skin over supporting spars and ribs. This method of construction, known as semi-monocoque, has been around for nearly 100 years."
He was talking about Monocoque construction, not the use of carbon fiber in Monocoque construction.
" . . . constructed with a rigid skin over supporting spars and ribs. This method of construction, known as semi-monocoque, has been around for nearly 100 years."
He was talking about Monocoque construction, not the use of carbon fiber in Monocoque construction.
Thank you, though semi-monocoque actually. Aluminum skinned airplane use aluminum ribs with the structural strength shared. I believe most carbon fiber airplane fuselages are full monocoque, meaning the skin provides the structural strength.
Not sure about that. Hinges are small and only comprise a small fraction of, say, a MacBook Air's total weight. Using carbon fiber on its hinges would make very little difference.
And I don't think CF is good at resisting friction or for surviving twisting forces.
He was talking about liquid metal not carbon fiber.
The topic is about carbon fiber, its high tensile strength, low weight, and low thermal expansion. I did look up monocoque construction before I responded. How exactly is such structural design relevant to the goal of creating a more compact and "thinner" devices, like the iPad. I am not an engineer, so it would be enlightening if monocoques or semi-monocoques make sense towards this goal.
The topic is about carbon fiber, its high tensile strength, low weight, and low thermal expansion. I did look up monocoque construction before I responded. How exactly is such structural design relevant to the goal of creating a more compact and "thinner" devices, like the iPad. I am not an engineer, so it would be enlightening if monocoques or semi-monocoques make sense towards this goal.
I think the MacBook Air is just about perfect just like it is thankyouverymuch.
If you talk to old hands in aviation, they will say that they don't trust carbon fiber airframes, but this is more a function of the slowness of aviation to accept new technologies than anything else. They just don't have the same long experience with the materials. This seems ironic to me, given the inherent problems with aluminum airframes, and all the difficult to find corrosion that can cause them to be expensive to maintain, if not fail outright. But it's the devil they know. Not sure what happened in the Lancair case, but lots of carbon fiber airframes have been certified by the FAA, so I don't think it's a fundamental problem. Lancair was one of the first, so perhaps that's why.
I was describing the process that Lancair used to try to get the FAA to approve it for aviation. They knew it was so strong that they couldn't get it to break in a reliable fashion for the FAA certification - they had to double the normal testing load to get it to break at all, and they realized it was way overbuilt, but enough so that the FAA finally relented and certified it. They had other problems, so they weren't the first to market certified planes, although carbon fiber (and fiber glass) have been used in experimental aircraft for years. Beechcraft was the first to get their Starship certified using primarily carbon fiber, which paved the way for others to consider its use (think 787 and all the problems they have run into). They later developed the Premier jet, but only used carbon fiber in the fuselage (just like the 787), and used aluminum in the flying surfaces (wings and tail, etc) and Airbus uses it in rudders and tailfins (which played a part in the disastrous accident in NY, where the rudder and tailfin shattered under overstress conditions) - which brings us back to the problem inherent with modern carbon-fiber- it is light, tough, but brittle, and can break under loads that may not be easy to predict, and is really difficult to repair properly and examine for internal fractures, delamination, or defects, but is, of course immune to corrosion, and is naturally quite electro-resistant.
Anyhow, now carbon fiber is used in exotic vehicles of all types, from sailboats to cars to planes, etc, and is (I guess) being considered to make the iPad lighter. Why not, if they can keep it from looking cheap in the process, I would applaud the effort.
I was describing the process that Lancair used to try to get the FAA to approve it for aviation. They knew it was so strong that they couldn't get it to break in a reliable fashion for the FAA certification - they had to double the normal testing load to get it to break at all, and they realized it was way overbuilt, but enough so that the FAA finally relented and certified it. They had other problems, so they weren't the first to market certified planes, although carbon fiber (and fiber glass) have been used in experimental aircraft for years. Beechcraft was the first to get their Starship certified using primarily carbon fiber, which paved the way for others to consider its use (think 787 and all the problems they have run into). They later developed the Premier jet, but only used carbon fiber in the fuselage (just like the 787), and used aluminum in the flying surfaces (wings and tail, etc) and Airbus uses it in rudders and tailfins (which played a part in the disastrous accident in NY, where the rudder and tailfin shattered under overstress conditions) - which brings us back to the problem inherent with modern carbon-fiber- it is light, tough, but brittle, and can break under loads that may not be easy to predict, and is really difficult to repair properly and examine for internal fractures, delamination, or defects, but is, of course immune to corrosion, and is naturally quite electro-resistant.
Anyhow, now carbon fiber is used in exotic vehicles of all types, from sailboats to cars to planes, etc, and is (I guess) being considered to make the iPad lighter. Why not, if they can keep it from looking cheap in the process, I would applaud the effort.
IIRC Lancair was a pioneer in using this material (they used to be based at the airport here) but so many have been type certified since. I'm thinking of Cirrus and nearly all of the light sport airplanes. I've run into A&Ps who still don't trust the material. All materials have their weakness, so to speak, but they know how to look for and treat corrosion. I always thought too much was made of the Airbus accident and the complicity of carbon fiber. Flying outside of the performance envelope is dangerous no matter how the airplane is built.
It's always amazing to me how many experts there are about carbon fiber. "I own a carbon fiber (insert favorite bike, tripod, kayak, etc. here), so I know everything there is to know about carbon fiber".
I've been in the Advanced Composite industry for 26 years. So, yeah, I do know what I am talking about. Strength? Hells yeah. Weathering? No problem. Expensive? Can be, doesn't need to be. In fact, I'd like to point out that complex metallic structures are usually much more expensive to fabricate than composites as they require individual manufacturing then a lengthy, time consuming assembly process. Composites can often be designed with features built in that not only increase strength but reduce costs as well.
One final word. Somebody posted that to cure carbon fiber you need an autoclave and 2000C. What a joke. Advanced composites can be cured anywhere from room temperature all the way up to around 800F. And you don't always need an autoclave. Vacuum is preferable, but presses can be used for really quick curing processes.
In the case of an iPad rear case, It would be very feasible to mass produce cases using thermoplastic/carbon fiber prepregs instead of epoxys. Processing time is reduced to minutes. Impact strength is phenominal (way better than aluminum or steel!). UV doesn't affect it, and it can all be done in presses, which would eliminate wasted processing materials, which would reduce costs even more. In bulk, you could expect these cases to cost in the $15 to $20 range. IDK what apple pays for the al cases, but it's probably not much less than that.
RF does struggle through CF, but we've all seen how creative Apple is with it's antennas.
Let's not forget the sex appeal of exotic materials, what ever those may be. This is probably the biggest decision factor for anybody. Does it look good? Does it do the intended job? Can we actually build it affordably?
Edit: I worked for the company that actually built the Starship fuselage... and no, it wasn't Beech. Also, I don't think weight has anything to do with this decision. Somebody posted that it might save 20-30 grams. Probably true, but 30 grams is 30 grams. Just ask a bike rider about spending $10 a bolt for Ti bolts that save about 1 gram per bolt.
Edit: I worked for the company that actually built the Starship fuselage... and no, it wasn't Beech. Also, I don't think weight has anything to do with this decision. Somebody posted that it might save 20-30 grams. Probably true, but 30 grams is 30 grams. Just ask a bike rider about spending $10 a bolt for Ti bolts that save about 1 gram per bolt.
In aircraft at least, it's more about reducing parasitic drag and the ability to form complex aerodynamic shapes. Still, the aviation industry is very conservative. Cessna entered the light sport market with a riveted aluminum airplane even though everybody else is building them with composites, because it's what they know, and what they believe is widely accepted.
Comments
I think that SJ's problem with 7" ipads will turn out to be a red herring.
Yeah, because the ultra-mobile market is extremely popular... just look how many UMPC's have been sold since they debuted compared to say, netbooks.
Sorry, but Steve Jobs is correct. There is a fine line between mobility and practicality. If you're on the go, most people will want to stick with something that they can carry on them at all times -- fits in their pocket. If you're not on the go, then most people will want something that is easier on the eyes for longer, more comfortable use.
UMPC's failed because they were too small to use for any extended amount of time to get any real work done.
7 Inch devices are the key to most of Apple's competitors. The reason is simple, Apple's iPad doesn't encroach on it's smaller iOS devices. Most of Apple's competitors can't compete with the smaller iOS devices. That means that if everyone else sticks to 7 inch devices, they can clean up sales from both ends of Apple products.
Unfortunately, I love my Mac too much to give it an android based companion. /bummer
You have to consider where the respective manufacturers want to end up. Apple has always been about being perceived as a premium option, preferring to let others pursue the bargain-basement segment.
The reason that I believe competitors are opting for a 7" form factor is that a few years from now, as the tablet market matures, they're going to want to be the ones selling $200 tablets. In contrast, Apple is perfectly happy to be the one selling $400 tablets. Whatever disadvantages there are to using the larger screen will be addressed in time as technology improves. Battery life, weight, storage capacity, processing power. All of those will improve and as they do it becomes easier for Apple to increase the iPad's screen resolution.
While Apple refines its 9.7" tablet, the competition will be busy producing progressively cheaper 7" devices. Probably, Apple will be one step ahead and as a result, consumers will be willing to pay more for Apple's offerings. Perceived quality will be helped by having a device with a larger screen.
Once I checked out an iPad on display by a local retailer my impression is of a device that does not seem at all too large. With a weight reduction that we all know is coming, it will be a very appealing form factor. If you want cheap, everybody else will have that covered in spades.That's not Apple's thing. Never has been, probably never will be.
I asked this very question when I was considering buying/building a carbon fiber Lancair aircraft back in 2001. The FAA approved the Lancair Columbia, but took an inordinate amount of time trying to come up with formulas that would explain precise breaking points (there is precious little in the literature or experience). The FAA likes metallic skins for wings, because you have to prove that the wing will withstand about 150% or so of probable maximum stress before breaking. Metal breaks in predictable fashion, whereas carbon fiber does not. In fact, the FAA just about gave up on trying to get the Lancair wing to break, which created a dilemma.
Anyhow, carbon fiber is more rigid, but may not bend as much before breaking, but can usually take much more force before shattering (so I have been led to believe).
I opted for an aluminum plane because I wanted a plane that was easier to repair, and one which resisted outside weathering better (carbon fiber does not hold up very well compared to aluminum).
Anyhow, a carbon-fiber case would certainly be lightweight, and could be designed to be very inflexible to resist twisting.
Whatever happened to all the ceramic uses that everyone was touting a few years back? Maybe carbon fiber is the way to go now, but I would still think the very thin liquid metal would make sense, as long as it was made non-conductive or insulated. Carbon fiber and ceramic can be made very insular, so I'm told, which may be a factor, and the ability to wick heat away from the batteries is also a factor.
If you talk to old hands in aviation, they will say that they don't trust carbon fiber airframes, but this is more a function of the slowness of aviation to accept new technologies than anything else. They just don't have the same long experience with the materials. This seems ironic to me, given the inherent problems with aluminum airframes, and all the difficult to find corrosion that can cause them to be expensive to maintain, if not fail outright. But it's the devil they know. Not sure what happened in the Lancair case, but lots of carbon fiber airframes have been certified by the FAA, so I don't think it's a fundamental problem. Lancair was one of the first, so perhaps that's why.
Boats, road cars, all formula 1 racing cars (which have tremendous impact strength) many different aircraft, both military and non military, and even other computer devices- Sony come to mind. the only thing they can be patenting is some specific manufacturing or design technique, not the use of the material. I would love them to use cfrp for this and the Macbook Air. It's light, won't dent like aluminium and won't dent or scratch other things. And when the device finally dies, it will make a lovely high tech tea tray.
Actually many of the modern ways of producing carbon fibre come from processes invented by a New Zealander by the name of John Britten of the Britten motorcycle fame.
He wanted a lightweight material that was strong enough to essentially become the frame and thus hold the weight of an engine. Not only that but actual parts of the engine were made in carborn fibre. While carbon fibre techniques existed none of them produced the product he wanted and needed so he developed his own. Not bad for a guy who did all of this in the back of his shed.
Britten patented the hell out of it.
Can someone explain to me exactly how carbon fiber breaks. I understand the concept that if you put stress on an object made out of the material in the same direction as the seams then it will break. What I don't get is how my tripods (I am a t producer) made out of carbon fiber have never broken
Exactly, carbon fiber is used in custom car creation for a reason. It's light-weight AND strong.
@"Apple Chief Executive Steve Jobs quieted those rumors < 7-inch iPad> in October, when he said a 7-inch tablet is too small for most consumers."
I don't suppose there have been any instances in the past of SJ intentionally leading the hounds off the scent?
Now let me count 'em....
While I agree that Steve is known for misdirection, in this case he's right. 7" is too small for a "tablet" while not really being any more portable than an iPad. You have to go smaller than 6" before portability improves significantly.
Once you're down to 6" you're into a whole new class of information appliance more akin to a big smartphone than a tablet. It happens to be the size that most interests me, but the one that no company is currently producing (the Dell Streak with it's outdated hardware and ancient version of Android really doesn't count).
Don't leave your iPad on the roof of your car and then drive off... My father-in-law figured this rule out the hard way.
His iPad was a crinkly sheet of metal and plastic by the end....
My girlfriend did that with her phone. It actually stayed on top of the car for a pretty good distance. We found it over half a mile away from the house in a pile of leaves by the curve. Would have never been able to find it if we didn't hear it ring.
I like carbon fiber. I don't see the batteries as being a surmountable problem. They are already based on lithium, the lightest metal.
Speaking of which, I wonder why Apple don't look at applying the unibody idea to magnesium instead of Aluminium. There is a glut at the moment and it's cheap. It's Lighter than Al and stiff. I know it is reactive as all hell, but maybe they could coat it with Titanium nitride or some other surface treatment to get round the problem.
The problemis in production, many a CNC mill has meant its death in a magnesium fire. The material does produce great light weight parts but is it worth the trouble.
Besides Apple could put an environmental spin on carbon fiber. My biggest concern would be the expense of the housing as it is likely to be more expensive than the CNC machined Aluminum. O
Airplanes, too. Anywhere lightness and strength are at a premium is a potential application for carbon fiber. Speaking of airplanes, they are most often constructed with a rigid skin over supporting spars and ribs. This method of construction, known as semi-monocoque, has been around for nearly 100 years.
Wow, 100 years? carbon fiber as a construction material? the same lineage as the carbon fiber used for cars, tripods, boats, planes, etc.?
References please.
As to the type of carbon fibers as a ligt construction material as we know today, it is more ca 1950's
Carbon fiber
This should not be confused with artificial fibers, with have carbon in them of course, or were derived initially from natural materials with carbon in them
synthetic fibers
with some dating back about a century ago (for the artificial fibers), but not really the same as the synthetic fibers that came in the mid 20th century.
There were indeed the first carbon fibers, based on the inventions of Edison, but those carbon fibers were not exactly the same technology as we know the carbon fibers used in the construction of the rigid, durable and lightweight material technologies used in tripods, cars, planes, boats, etc.
Sure one could claim the historical evolution of the technology from those early carbon fibers, but then Nature has "accidentally created polymeric carbons, even before man ever was in this world.
Boats are mostly made from fiberglass. An entire board hull made from carbon fiber would cost several times as much.
I think he's referring to high end racing yachts analogous to the Formula I racing cars. I believe America's Cup yachts all have carbon fiber incorporated in their hulls.
Wow, 100 years? carbon fiber as a construction material? the same lineage as the carbon fiber used for cars, tripods, boats, planes, etc.?
References please.
Read more carefully. He said,
" . . . constructed with a rigid skin over supporting spars and ribs. This method of construction, known as semi-monocoque, has been around for nearly 100 years."
He was talking about Monocoque construction, not the use of carbon fiber in Monocoque construction.
Read more carefully. He said,
" . . . constructed with a rigid skin over supporting spars and ribs. This method of construction, known as semi-monocoque, has been around for nearly 100 years."
He was talking about Monocoque construction, not the use of carbon fiber in Monocoque construction.
Thank you, though semi-monocoque actually. Aluminum skinned airplane use aluminum ribs with the structural strength shared. I believe most carbon fiber airplane fuselages are full monocoque, meaning the skin provides the structural strength.
Not sure about that. Hinges are small and only comprise a small fraction of, say, a MacBook Air's total weight. Using carbon fiber on its hinges would make very little difference.
And I don't think CF is good at resisting friction or for surviving twisting forces.
He was talking about liquid metal not carbon fiber.
The topic is about carbon fiber, its high tensile strength, low weight, and low thermal expansion. I did look up monocoque construction before I responded. How exactly is such structural design relevant to the goal of creating a more compact and "thinner" devices, like the iPad. I am not an engineer, so it would be enlightening if monocoques or semi-monocoques make sense towards this goal.
I think the MacBook Air is just about perfect just like it is thankyouverymuch.
If you talk to old hands in aviation, they will say that they don't trust carbon fiber airframes, but this is more a function of the slowness of aviation to accept new technologies than anything else. They just don't have the same long experience with the materials. This seems ironic to me, given the inherent problems with aluminum airframes, and all the difficult to find corrosion that can cause them to be expensive to maintain, if not fail outright. But it's the devil they know. Not sure what happened in the Lancair case, but lots of carbon fiber airframes have been certified by the FAA, so I don't think it's a fundamental problem. Lancair was one of the first, so perhaps that's why.
I was describing the process that Lancair used to try to get the FAA to approve it for aviation. They knew it was so strong that they couldn't get it to break in a reliable fashion for the FAA certification - they had to double the normal testing load to get it to break at all, and they realized it was way overbuilt, but enough so that the FAA finally relented and certified it. They had other problems, so they weren't the first to market certified planes, although carbon fiber (and fiber glass) have been used in experimental aircraft for years. Beechcraft was the first to get their Starship certified using primarily carbon fiber, which paved the way for others to consider its use (think 787 and all the problems they have run into). They later developed the Premier jet, but only used carbon fiber in the fuselage (just like the 787), and used aluminum in the flying surfaces (wings and tail, etc) and Airbus uses it in rudders and tailfins (which played a part in the disastrous accident in NY, where the rudder and tailfin shattered under overstress conditions) - which brings us back to the problem inherent with modern carbon-fiber- it is light, tough, but brittle, and can break under loads that may not be easy to predict, and is really difficult to repair properly and examine for internal fractures, delamination, or defects, but is, of course immune to corrosion, and is naturally quite electro-resistant.
Anyhow, now carbon fiber is used in exotic vehicles of all types, from sailboats to cars to planes, etc, and is (I guess) being considered to make the iPad lighter. Why not, if they can keep it from looking cheap in the process, I would applaud the effort.
I was describing the process that Lancair used to try to get the FAA to approve it for aviation. They knew it was so strong that they couldn't get it to break in a reliable fashion for the FAA certification - they had to double the normal testing load to get it to break at all, and they realized it was way overbuilt, but enough so that the FAA finally relented and certified it. They had other problems, so they weren't the first to market certified planes, although carbon fiber (and fiber glass) have been used in experimental aircraft for years. Beechcraft was the first to get their Starship certified using primarily carbon fiber, which paved the way for others to consider its use (think 787 and all the problems they have run into). They later developed the Premier jet, but only used carbon fiber in the fuselage (just like the 787), and used aluminum in the flying surfaces (wings and tail, etc) and Airbus uses it in rudders and tailfins (which played a part in the disastrous accident in NY, where the rudder and tailfin shattered under overstress conditions) - which brings us back to the problem inherent with modern carbon-fiber- it is light, tough, but brittle, and can break under loads that may not be easy to predict, and is really difficult to repair properly and examine for internal fractures, delamination, or defects, but is, of course immune to corrosion, and is naturally quite electro-resistant.
Anyhow, now carbon fiber is used in exotic vehicles of all types, from sailboats to cars to planes, etc, and is (I guess) being considered to make the iPad lighter. Why not, if they can keep it from looking cheap in the process, I would applaud the effort.
IIRC Lancair was a pioneer in using this material (they used to be based at the airport here) but so many have been type certified since. I'm thinking of Cirrus and nearly all of the light sport airplanes. I've run into A&Ps who still don't trust the material. All materials have their weakness, so to speak, but they know how to look for and treat corrosion. I always thought too much was made of the Airbus accident and the complicity of carbon fiber. Flying outside of the performance envelope is dangerous no matter how the airplane is built.
I've been in the Advanced Composite industry for 26 years. So, yeah, I do know what I am talking about. Strength? Hells yeah. Weathering? No problem. Expensive? Can be, doesn't need to be. In fact, I'd like to point out that complex metallic structures are usually much more expensive to fabricate than composites as they require individual manufacturing then a lengthy, time consuming assembly process. Composites can often be designed with features built in that not only increase strength but reduce costs as well.
One final word. Somebody posted that to cure carbon fiber you need an autoclave and 2000C. What a joke. Advanced composites can be cured anywhere from room temperature all the way up to around 800F. And you don't always need an autoclave. Vacuum is preferable, but presses can be used for really quick curing processes.
In the case of an iPad rear case, It would be very feasible to mass produce cases using thermoplastic/carbon fiber prepregs instead of epoxys. Processing time is reduced to minutes. Impact strength is phenominal (way better than aluminum or steel!). UV doesn't affect it, and it can all be done in presses, which would eliminate wasted processing materials, which would reduce costs even more. In bulk, you could expect these cases to cost in the $15 to $20 range. IDK what apple pays for the al cases, but it's probably not much less than that.
RF does struggle through CF, but we've all seen how creative Apple is with it's antennas.
Let's not forget the sex appeal of exotic materials, what ever those may be. This is probably the biggest decision factor for anybody. Does it look good? Does it do the intended job? Can we actually build it affordably?
Edit: I worked for the company that actually built the Starship fuselage... and no, it wasn't Beech. Also, I don't think weight has anything to do with this decision. Somebody posted that it might save 20-30 grams. Probably true, but 30 grams is 30 grams. Just ask a bike rider about spending $10 a bolt for Ti bolts that save about 1 gram per bolt.
Edit: I worked for the company that actually built the Starship fuselage... and no, it wasn't Beech. Also, I don't think weight has anything to do with this decision. Somebody posted that it might save 20-30 grams. Probably true, but 30 grams is 30 grams. Just ask a bike rider about spending $10 a bolt for Ti bolts that save about 1 gram per bolt.
In aircraft at least, it's more about reducing parasitic drag and the ability to form complex aerodynamic shapes. Still, the aviation industry is very conservative. Cessna entered the light sport market with a riveted aluminum airplane even though everybody else is building them with composites, because it's what they know, and what they believe is widely accepted.
But how careless about phones are we getting. Plastic that was
once hailed as indestructible is no longer enough and we now need
material used on aircraft for phones?