Carbon Bikes and Quality Control

On Tue, 6 Jun 2017 18:35:26 -0400, Frank Krygowski
wrote:

On 6/6/2017 5:52 AM, John B. wrote:
On Mon, 05 Jun 2017 12:53:53 -0700, Joerg
wrote:

On 2017-06-05 10:20, Doug Landau wrote:
On Sunday, June 4, 2017 at 10:02:40 AM UTC-7, Joerg wrote:
On 2017-06-04 06:50, Jeff Liebermann wrote:
On Sun, 04 Jun 2017 14:37:28 +0700, John B.
wrote:

Well, if you are going to be all electronic there should be no
problem to have a "tinkle, tinkle" setting, a "ding, ding"
setting and a "GET OUT THE F--KING WAY!" setting.

All good ideas but I think some psychology might be better. I
think I'll try synthesizing the sound of an iPhone ringing. That
should stop anyone ahead in their tracks as they look down at
their iPhone to see who's calling. Since they've now stopped
moving, I can usually weave (or zip) around them. If that
doesn't work, I'll try the doppler shifted sound of screeching
tires.


Electronic is too wimpy. This ought to do:

https://www.youtube.com/watch?v=BGWRB2UNOmI

****it. That video absolutely will not dispense with the 15-second
ad, no matter how many times you hit Control-R. **** it.


Youtube has begun to nag more persistently and they make you wait them
out. A really nasty one is an IBM Watson ad that has caused me to
abandon Youtube at times.

I have developed a habit of doing some other chore while watching out of
the corner of an eye, then turning to the screen when the fluff is over.
Often I miss it and then just "spool back" to the beginning. I never
really see the ads consciously so I couldn't even tell you what any one
of them is about or what they wanted to sell.

The problem with Youtube is that it is a movie and can be made to
prove just about anything that the maker wants to prove.

As an example - This was widely believed
https://www.youtube.com/watch?v=Y90vnB6gUME

until this
https://www.youtube.com/watch?v=naSZBdJoEbM
came out.

Although Snopes helped, as usual.

That ain't nottin! I used to fly around in airplans that didn't have
no wings at all :-)
--
Cheers,

John B.

On Monday, May 29, 2017 at 11:40:18 AM UTC-4, wrote:

So until we have tort reform we have little way of knowing just how safe a carbon fiber frame and fork are.

This sort of goofy hyperbole just makes you look shallowpated.

And I wonder why carbon fiber tubes are so unsafe, now that FAA-certified aircraft are built with them. There are plenty of tube clusters and joints on these Carbon Cubs. You can see a few of them he
http://cubcrafters.com/
http://cubcrafters.com/carboncub/ss

If you'll look at the wing strut connects at the fuselage, that would be a three-tube joint. See the imprints? And in the rugged bush like the Alaskan outback where these aircraft (Super Cub progeny) land on rocky shores or rough sod fields, these aircraft sustain tremendous stresses.

As an aircraft owner of a tube-and-rag aircraft (Taylorcraft with steel tubes gas-welded at the clusters) and an avid mountain biker, I'm just wondering.

I have done fiberglas and carbon fiber layups. If they are done properly, the tensile and compressive strength is close to 1,000,000 psi. Boeing demonstrated this impressive fact years ago.

Maybe some of these bike manufacturers have trouble with QC.

On Saturday, July 15, 2017 at 10:35:01 AM UTC-7, Ashevilliot wrote:
On Monday, May 29, 2017 at 11:40:18 AM UTC-4, wrote:

So until we have tort reform we have little way of knowing just how safe a carbon fiber frame and fork are.

This sort of goofy hyperbole just makes you look shallowpated.

And I wonder why carbon fiber tubes are so unsafe, now that FAA-certified aircraft are built with them. There are plenty of tube clusters and joints on these Carbon Cubs. You can see a few of them he
http://cubcrafters.com/
http://cubcrafters.com/carboncub/ss

If you'll look at the wing strut connects at the fuselage, that would be a three-tube joint. See the imprints? And in the rugged bush like the Alaskan outback where these aircraft (Super Cub progeny) land on rocky shores or rough sod fields, these aircraft sustain tremendous stresses.

As an aircraft owner of a tube-and-rag aircraft (Taylorcraft with steel tubes gas-welded at the clusters) and an avid mountain biker, I'm just wondering.

I have done fiberglas and carbon fiber layups. If they are done properly, the tensile and compressive strength is close to 1,000,000 psi. Boeing demonstrated this impressive fact years ago.

Maybe some of these bike manufacturers have trouble with QC.

Look dumbass - if you're not an engineer I suggest you shut the F up. If you don't understand the effects of loadings on construction materials pull your head out of your A and try and learn something before posting any F-ing thing like "shallowpated".

Exactly what are your credentials on materials science?

Here is another view of the use of carbon fiber layups in the aircraft industry.

https://www.youtube.com/watch?v=5A2VSg0pFcE

Notice that some titanium is also used in at least one of the Carbon Cubs.

About 15 years ago I participated in a wing-loading test of White Lightning Aircraft wings designed by engineer Hal C. "Nick" Jones of WLAC, Inc., of Walterboro, SC. The wings were loaded with sandbags to 10 G's and did not break. and due to high elastic modulus, barely even sagged. The main spar in each of the two wings is a tapered tubular structure made of radial-wound carbon fiber layups. The spar serves along with the forward compartment of each wing as a tank for 100LL aerogas, total 80 gal.

Most of my STEM training is in chemistry and biology, although I studied physics, calculus, and some organic chemistry in college, and attended aviation maintenance school. I am not an engineer, and certainly not a jack of all trades, although I did learn something about loads, stress risers, fatigue, vacuum-bagging, weave orientation, and other factors which affect the strength and durability of composite structures, including carbon fiber structures. That's the reason why I believe that a carbon fiber bicycle can be safe and durable, and that the reason for catastrophic failures is probably human error in the layups.

On Sat, 15 Jul 2017 10:34:57 -0700 (PDT), Ashevilliot
wrote:

On Monday, May 29, 2017 at 11:40:18 AM UTC-4, wrote:

So until we have tort reform we have little way of knowing just how safe a carbon fiber frame and fork are.

This sort of goofy hyperbole just makes you look shallowpated.

And I wonder why carbon fiber tubes are so unsafe, now that FAA-certified aircraft are built with them. There are plenty of tube clusters and joints on these Carbon Cubs. You can see a few of them he
http://cubcrafters.com/
http://cubcrafters.com/carboncub/ss

If you'll look at the wing strut connects at the fuselage, that would be a three-tube joint. See the imprints? And in the rugged bush like the Alaskan outback where these aircraft (Super Cub progeny) land on rocky shores or rough sod fields, these aircraft sustain tremendous stresses.

As an aircraft owner of a tube-and-rag aircraft (Taylorcraft with steel tubes gas-welded at the clusters) and an avid mountain biker, I'm just wondering.

I have done fiberglas and carbon fiber layups. If they are done properly, the tensile and compressive strength is close to 1,000,000 psi. Boeing demonstrated this impressive fact years ago.

Maybe some of these bike manufacturers have trouble with QC.


I suspect that the difference is that the airplane is designed to be
"strong enough" while the bicycle is designed to be "light enough".

And, no the strength of properly done lay ups is not close to
1,000,000 psi. In fact it you believe that then I would have to say
that your knowledge of composites is sadly lacking.
--
Cheers,

John B.

On Saturday, July 15, 2017 at 7:17:36 PM UTC-7, John B. wrote:
On Sat, 15 Jul 2017 10:34:57 -0700 (PDT), Ashevilliot
wrote:

On Monday, May 29, 2017 at 11:40:18 AM UTC-4, wrote:

So until we have tort reform we have little way of knowing just how safe a carbon fiber frame and fork are.

This sort of goofy hyperbole just makes you look shallowpated.

And I wonder why carbon fiber tubes are so unsafe, now that FAA-certified aircraft are built with them. There are plenty of tube clusters and joints on these Carbon Cubs. You can see a few of them he
http://cubcrafters.com/
http://cubcrafters.com/carboncub/ss

If you'll look at the wing strut connects at the fuselage, that would be a three-tube joint. See the imprints? And in the rugged bush like the Alaskan outback where these aircraft (Super Cub progeny) land on rocky shores or rough sod fields, these aircraft sustain tremendous stresses.

As an aircraft owner of a tube-and-rag aircraft (Taylorcraft with steel tubes gas-welded at the clusters) and an avid mountain biker, I'm just wondering.

I have done fiberglas and carbon fiber layups. If they are done properly, the tensile and compressive strength is close to 1,000,000 psi. Boeing demonstrated this impressive fact years ago.

Maybe some of these bike manufacturers have trouble with QC.


I suspect that the difference is that the airplane is designed to be
"strong enough" while the bicycle is designed to be "light enough".

And, no the strength of properly done lay ups is not close to
1,000,000 psi. In fact it you believe that then I would have to say
that your knowledge of composites is sadly lacking.

This was something I thought would be self-evident. In kit aircraft they use lighter materials NOT to be lighter but to put more strength into the same weight. Weight is nothing more than a side issue.

On bikes we are presently seeing them advertising 12.5 lb all up 54 cm bikes.

Someone published a failure rate test and it showed that all materials failed with one application of 100% maximum rated load. There was a linear line going down with all materials - aluminum and CF failed after application of so many 50% loads but for all loads under 75% steel didn't fail - it had no fatigue failures.

Now emailing Cannondale and Specialized engineers they convinced me that you could make a CF bike so strong that the fatigue life at 50% was effectively longer than the lifetime of an owner. They were not able to convince me that you could have a small enough quality control failure rate.

And it makes you wonder why a Gianni Motta from 40 years ago can still have almost an unlimited lifespan while an older CF _will_ fail eventually.

On Sunday, July 16, 2017 at 4:43:31 PM UTC-4, wrote:
On Saturday, July 15, 2017 at 7:17:36 PM UTC-7, John B. wrote:
On Sat, 15 Jul 2017 10:34:57 -0700 (PDT), Ashevilliot
wrote:

On Monday, May 29, 2017 at 11:40:18 AM UTC-4, wrote:

So until we have tort reform we have little way of knowing just how safe a carbon fiber frame and fork are.

This sort of goofy hyperbole just makes you look shallowpated.

And I wonder why carbon fiber tubes are so unsafe, now that FAA-certified aircraft are built with them. There are plenty of tube clusters and joints on these Carbon Cubs. You can see a few of them he
http://cubcrafters.com/
http://cubcrafters.com/carboncub/ss

If you'll look at the wing strut connects at the fuselage, that would be a three-tube joint. See the imprints? And in the rugged bush like the Alaskan outback where these aircraft (Super Cub progeny) land on rocky shores or rough sod fields, these aircraft sustain tremendous stresses.

As an aircraft owner of a tube-and-rag aircraft (Taylorcraft with steel tubes gas-welded at the clusters) and an avid mountain biker, I'm just wondering.

I have done fiberglas and carbon fiber layups. If they are done properly, the tensile and compressive strength is close to 1,000,000 psi. Boeing demonstrated this impressive fact years ago.

Maybe some of these bike manufacturers have trouble with QC.


I suspect that the difference is that the airplane is designed to be
"strong enough" while the bicycle is designed to be "light enough".

And, no the strength of properly done lay ups is not close to
1,000,000 psi. In fact it you believe that then I would have to say
that your knowledge of composites is sadly lacking.

This was something I thought would be self-evident. In kit aircraft they use lighter materials NOT to be lighter

That would be false. "Add lightness" is a motto of the aircraft industry. The Carbon Cub is 300 lbs. lighter than its predecessor, due to the use of lightweight materials like carbon fiber, titanium, and chromoly steel. Wing ribs appear to be aluminum alloy and are said to be lighter than the old Cub ribs from the fifties.

I was mistaken that the Carbon Cub's fuselage is carbon. It is made of lightweight welded steel tubes which are alloys of iron, carbon, chromium, and molybdenum -- chromoly.


but to put more strength into the same weight. Weight is nothing more than a side issue.


Not so. The object of the Super Cub is an optimum power-to-weight ratio. You can now see Alaskan Cubs breaking ground after a takeoff roll of a few feet. That could not be done with the old Cub.

Boeing's Dreamliner is 20% lighter than the equivalent aluminum ship. And better strength-to-weight ratio, which permits great passenger and cargo loads, is due to the use of composites like carbon fiber, which is stressed (according to Boeing) to 883 kpsi. Not that far away from tensile stress achievements Boeing verified in its labs in Seattle: more than 1,000 kpsi.

On bikes we are presently seeing them advertising 12.5 lb all up 54 cm bikes.

Someone published a failure rate test and it showed that all materials failed with one application of 100% maximum rated load. There was a linear line going down with all materials - aluminum and CF failed after application of so many 50% loads but for all loads under 75% steel didn't fail - it had no fatigue failures.


Very interesting. I ride a favorite mountain bike make of chromoly. I have carried it on my airplane with the wheels and fork removed.

Now emailing Cannondale and Specialized engineers they convinced me that you could make a CF bike so strong that the fatigue life at 50% was effectively longer than the lifetime of an owner. They were not able to convince me that you could have a small enough quality control failure rate.

And it makes you wonder why a Gianni Motta from 40 years ago can still have almost an unlimited lifespan while an older CF _will_ fail eventually.

What is the material of the Motta frame?

On Wednesday, July 26, 2017 at 9:24:26 AM UTC-7, Ashevilliot wrote:
On Sunday, July 16, 2017 at 4:43:31 PM UTC-4, wrote:

This was something I thought would be self-evident. In kit aircraft they use lighter materials NOT to be lighter

That would be false. "Add lightness" is a motto of the aircraft industry.. The Carbon Cub is 300 lbs. lighter than its predecessor, due to the use of lightweight materials like carbon fiber, titanium, and chromoly steel. Wing ribs appear to be aluminum alloy and are said to be lighter than the old Cub ribs from the fifties.

You have to firstly understand what "side issue" means. Small aircraft are lighter - marginally. They use high performance materials to make aircraft stronger since the major causes of failure is material failure.

Not so. The object of the Super Cub is an optimum power-to-weight ratio. You can now see Alaskan Cubs breaking ground after a takeoff roll of a few feet. That could not be done with the old Cub.

And the original Cub had something like 65 horsepower and present versions have between double and triple the power.

Boeing's Dreamliner is 20% lighter than the equivalent aluminum ship. And better strength-to-weight ratio, which permits great passenger and cargo loads, is due to the use of composites like carbon fiber, which is stressed (according to Boeing) to 883 kpsi. Not that far away from tensile stress achievements Boeing verified in its labs in Seattle: more than 1,000 kpsi.

Uh - don't you detect a different mission between a sports aircraft and a commercial airliner?

What is the material of the Motta frame?

Gianni Motta was a professional road racer that won the Giro in 1980. As all the bikes of that time and those he put his name on after he retired they were steel.