Coroner criticises CASA over light plane crash deaths
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The last fool is not yet born...
Dear me, Sunfish.
If only you knew who you were talking to.
Let me just say that the point Wiz is making has little to do with how many atoms of cadmium you have baked into whatever it is you are talking about.
I think you've gone beyond the concept a little, weren't we talking about the loads that automotive and aircraft parts were undergoing during their operation?? A fuel pump is a fuel pump is a fuel pump. Whether it pumps fuel at sea level or at 20,000' it is still a fuel pump.
520.
If only you knew who you were talking to.
Let me just say that the point Wiz is making has little to do with how many atoms of cadmium you have baked into whatever it is you are talking about.
I think you've gone beyond the concept a little, weren't we talking about the loads that automotive and aircraft parts were undergoing during their operation?? A fuel pump is a fuel pump is a fuel pump. Whether it pumps fuel at sea level or at 20,000' it is still a fuel pump.
520.
Oh dear, if only you knew who you were talking to.
Continental - with the greatest of respect, and I'm being picky but...wrong! Go ahead and fit your automotive fuel pump that looks like the aviation equivalent, and is made by the same company, it might even have the same part number. Better still, fit one made by a competitor, or just go into Repco and buy a Taiwanese one instead of AC Delco.
Now we are at 20,000 feet. Ever heard of net positive suction head? What happens when the vapour pressure of the fuel exceeds it? Remember to subtract 20,000 feet worth of altitude.
The atmospheric pressure is now 6.73 psi instead of 14.7 psi. Now Avgas has a vapour pressure of around 38-49 Kpa. Road fuel is around 70 Kpa. Maybe your fuel filter is partially clogged as well, further decreasing the NPSH.
Now your little pump has decided its not going to work, a little bubble of vapour sits in the pump and goes backwards and forwards. The "identical" aviation pump had a slightly lower inlet valve opening pressure to keep NPSH positive. Furthermore the opening pressure has been calibrated and tested. Your engine stops.
As I said in my previous post, there are lots of automotive bits that look exactly the same as aviation bits.
You have no idea if your fuel pump with the same part number stamped on it:
(a) Has completely different internals but uses the same housing as the automotive pump - complete with part number.
(b) Has different seal materials from the automotive pump.
(c) Has different valve opening pressures from the automotive pump.
(d) Has higher spec wire or insulation.
(e) Is actually identical to the automotive pump, but has undergone 24 hours of pumping in a "burn-in" test chamber, to remove infant mortality failure risks.
(f) Is actually the same pump, but is selected from the batch of normal pumps on the basis of superior electrical performance or pump perfomance.
Having said that, I am being picky, you are very probably right that you can make the substitution in the case of a little fuel pump in a Warrior, however can you then match the traceability requirements and do it legally?
I know years ago at AN there was a perennial search for cheap local equivalents of Boeing specified articles, from the glue that help the rubber cap on the radome on up. Sometimes they were found, sometimes not.
I also know that while working at HdeH we were several times approached to make all sorts of "spares" for various aircraft often by fly by night folk looking to get round export controls or just to make a quick buck. The drawings of just about everything the U.S government buys aviation-wise is on the Federal Supply Catalogue (FSCM), and cheap copies of this stuff has tragically killed quite a few people, especially in helicopters.
Tthe bottom line is that just because it looks the same, or does the same job in a car, doesn't necessarily mean it will perfom the same in an aircraft.
Continental - with the greatest of respect, and I'm being picky but...wrong! Go ahead and fit your automotive fuel pump that looks like the aviation equivalent, and is made by the same company, it might even have the same part number. Better still, fit one made by a competitor, or just go into Repco and buy a Taiwanese one instead of AC Delco.
Now we are at 20,000 feet. Ever heard of net positive suction head? What happens when the vapour pressure of the fuel exceeds it? Remember to subtract 20,000 feet worth of altitude.
The atmospheric pressure is now 6.73 psi instead of 14.7 psi. Now Avgas has a vapour pressure of around 38-49 Kpa. Road fuel is around 70 Kpa. Maybe your fuel filter is partially clogged as well, further decreasing the NPSH.
Now your little pump has decided its not going to work, a little bubble of vapour sits in the pump and goes backwards and forwards. The "identical" aviation pump had a slightly lower inlet valve opening pressure to keep NPSH positive. Furthermore the opening pressure has been calibrated and tested. Your engine stops.
As I said in my previous post, there are lots of automotive bits that look exactly the same as aviation bits.
You have no idea if your fuel pump with the same part number stamped on it:
(a) Has completely different internals but uses the same housing as the automotive pump - complete with part number.
(b) Has different seal materials from the automotive pump.
(c) Has different valve opening pressures from the automotive pump.
(d) Has higher spec wire or insulation.
(e) Is actually identical to the automotive pump, but has undergone 24 hours of pumping in a "burn-in" test chamber, to remove infant mortality failure risks.
(f) Is actually the same pump, but is selected from the batch of normal pumps on the basis of superior electrical performance or pump perfomance.
Having said that, I am being picky, you are very probably right that you can make the substitution in the case of a little fuel pump in a Warrior, however can you then match the traceability requirements and do it legally?
I know years ago at AN there was a perennial search for cheap local equivalents of Boeing specified articles, from the glue that help the rubber cap on the radome on up. Sometimes they were found, sometimes not.
I also know that while working at HdeH we were several times approached to make all sorts of "spares" for various aircraft often by fly by night folk looking to get round export controls or just to make a quick buck. The drawings of just about everything the U.S government buys aviation-wise is on the Federal Supply Catalogue (FSCM), and cheap copies of this stuff has tragically killed quite a few people, especially in helicopters.
Tthe bottom line is that just because it looks the same, or does the same job in a car, doesn't necessarily mean it will perfom the same in an aircraft.
Last edited by Sunfish; 15th Dec 2005 at 19:54.
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Most Disturbing!!!!
If only you knew who you were talking to.
I can't believe some of the statements being made here about using non aviation approved parts. Apart from the legalities, i.e. traceability etc, I'm bloody sure I don't want to be the one to find out at FL350, that the flugal dampner you fitted (wiz/520) isn't working
I doubt if I will be comforted by the fact that it has the same part number from Repco as from P&W.BTW, I'll bet Melbourne to a brick that the AC Delco Pumps from Repco, do not, can not and should not be used in aircraft. If you want to try it, may I suggest you start with a Turbo 182RG
. Are you guys serious, or do you see this as another opportunity to have a go at Sunfish (which appears to be a sport thesedays).
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Bugsmasherdriverandjediknite
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Nasa, read my post very carefully and slowly. I nowhere in that post sanctioned replacing parts of an automotive nature into aircraft. I simply pointed out the fact that some parts in aircraft are built by automotive parts manufacturers. Lets also get something else straight. If the part number on one part is the same as another part made by the the same manufacturer...... Its the same frikken part. part numbers change with changes in the part.........for identification and tracability purposes. thats what part numbers are for, fer christ sake.
you all missed the whole point. work is work. regardless of weather it is on an aircraft or a vehicle, if its doing the same job, its doing the same amount of work.....pretty simple.
(I'm really going to worry when my door handles on my 172 that cost $400 and have the same part number, and strangely enough look and fit the same as a 1974 chrysler part that cost $30 from repco, cause a devastating and uncontrolled crash).
you all missed the whole point. work is work. regardless of weather it is on an aircraft or a vehicle, if its doing the same job, its doing the same amount of work.....pretty simple.
(I'm really going to worry when my door handles on my 172 that cost $400 and have the same part number, and strangely enough look and fit the same as a 1974 chrysler part that cost $30 from repco, cause a devastating and uncontrolled crash).
Wiz, with respect, unless Cessna tells you that your door handle is exactly the same as the Chrysler one, then you cannot use it.
Using the door handle example, having the same part number can merely mean that it was produced in the same injection die. Unless you can test the composition of the alloy and its microstructure, you cannot say its identical. Thats exactly what happened to the Cessna in question. If it isn't identical, then you are going to have to get an engineer to sign off on its substitution.
I've run a company that built automotive parts, and I've worked for a company that made aircraft structure and engine parts. I've worked in an airline maintenance division as well. I assure you that reasons (a) to (f) on my previous post are from my real experience.
Furthermore CASA's little maintenance guide for Pilots specifically mentions the problem of wheel bearings with identical part numbers but different ABEC bearing grades.
Having said all that, it probably is identical. I'm amazed at people having to pay $400 for a bit of vacuum moulded PVC interior trim as well, and I wonder why nobody has started a carbon fibre aftermarket replacement business, assuming flammability requirements can be met.
Using the door handle example, having the same part number can merely mean that it was produced in the same injection die. Unless you can test the composition of the alloy and its microstructure, you cannot say its identical. Thats exactly what happened to the Cessna in question. If it isn't identical, then you are going to have to get an engineer to sign off on its substitution.
I've run a company that built automotive parts, and I've worked for a company that made aircraft structure and engine parts. I've worked in an airline maintenance division as well. I assure you that reasons (a) to (f) on my previous post are from my real experience.
Furthermore CASA's little maintenance guide for Pilots specifically mentions the problem of wheel bearings with identical part numbers but different ABEC bearing grades.
Having said all that, it probably is identical. I'm amazed at people having to pay $400 for a bit of vacuum moulded PVC interior trim as well, and I wonder why nobody has started a carbon fibre aftermarket replacement business, assuming flammability requirements can be met.
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Hmmmm Touchy
the wizard of auz .....Get out of the wrong side of bed did we. or maybe finding a little hard to p!ss today 
Really isn't that big a leap from the content of your post to assuming advocating and condoning the use of non aviation approved parts, however, I concede you did not directly say that
......to Quote Continental-520
Really not that far removed from
As you're
would you please be so good as to tell me which companies manufacture non aviation spare parts on the same production line as aviation approved spare parts.
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Really isn't that big a leap from the content of your post to assuming advocating and condoning the use of non aviation approved parts, however, I concede you did not directly say that
......to Quote Continental-520
A fuel pump is a fuel pump is a fuel pump. Whether it pumps fuel at sea level or at 20,000' it is still a fuel pump.
I can't believe some of the statements being made here about using non aviation approved parts.
I am in the trade that deals with these matters and I strongly disagree with you.
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Um, negative...
No, I'm not suggesting using non aviation parts for aviation purposes either, but what we are trying to convey here is that the aviation parts are outrageously overpriced for the differences they bear to, say, automotive ones.
And yes, a fuel pump in a car will still pump fuel in a car at 20,000 feet just as an aircraft one will doing so in an aircraft.
Sheesh!
520.
And yes, a fuel pump in a car will still pump fuel in a car at 20,000 feet just as an aircraft one will doing so in an aircraft.
Sheesh!
520.
Bugsmasherdriverandjediknite
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Nasa, mate, I'm having no problems pissing at all. nor did I get out of bed on the wrong side. I was just exasperated that some one could read what I wrote and come to the conclusion that I sanctioned the use of non approved parts in an aircraft.
I bought an oil filter adapter from the USA recently. The STC'd part has a different PN but otherwise identical to the unit that can be put on Experimental aircraft. An extra USD55 for the STC/PMA'd part. Then an extra US$100 for the bit of paper that CASA needs! Beats me why they just can't accept the manufacturer's release certificate but they require an FAA delegate's signature.
I also worked at an aircraft factory in the USA where we had a production certificate, built GA aircraft, plus made some Experimental airplanes, some kits for home-builders and parts for all. All down the same production line. We also acquired some standard hardware parts for the certified aircraft. I recall spending some effort in getting a bicycle grip past the flammability requirements.
I also worked at an aircraft factory in the USA where we had a production certificate, built GA aircraft, plus made some Experimental airplanes, some kits for home-builders and parts for all. All down the same production line. We also acquired some standard hardware parts for the certified aircraft. I recall spending some effort in getting a bicycle grip past the flammability requirements.
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Tallk About $$$$$$s
520 If you want to talk about $$$s and the difference betwixt aviation and non aviation parts and the cost thereof, then that's another thread altogether.
Give you a quick sample of the ridiculous.... I'm in the midst of negotiating the purchase of a somewhat technologically advanced mid size business jet at the moment. My client has asked for some modifications to suit his personal taste, one of which was changing the tables so that they would be more stable.....Cost to do this, USD$128,000, but then again, that is for two
To be PMA approved is not a cheap exercise and you'll find that those that go into PMA parts will try and amortize their setup cost over the ongoing sale of the parts.
wiz After a little while, you'll come to learn that aviation tends to be somewhat exasperating at the best of times
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Give you a quick sample of the ridiculous.... I'm in the midst of negotiating the purchase of a somewhat technologically advanced mid size business jet at the moment. My client has asked for some modifications to suit his personal taste, one of which was changing the tables so that they would be more stable.....Cost to do this, USD$128,000, but then again, that is for two
To be PMA approved is not a cheap exercise and you'll find that those that go into PMA parts will try and amortize their setup cost over the ongoing sale of the parts.
wiz After a little while, you'll come to learn that aviation tends to be somewhat exasperating at the best of times
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NASA, after 13 yrs in the industry, I am in a constant state of exsasperation when it comes to paying for parts in australia. I generally buy my parts ex US now days for planned maintanace, and pay up to %60 less than I do locally. Now If I was in the habit of fitting non approved parts, that would be another %50 off. recently had to buy one bolt.........pretty common size and not a critical position in the aircraft. Aviation = $16.90 + GST. non aviation and of a higher grade than the approved one, $1.30 Inc GST.
Just makes you wonder, don't it.
Just makes you wonder, don't it.
Wiz, you appear to be talking about two different problems:
(a) Australian distributors price gouging.
(b) Substitution of non aviation parts.
I'm sorry to have to say this, but again, your example of a "non -aviation bolt of a higher grade" being cheaper is still a dangerous example.
Let's look at it first from an insurance perspective. If you fit something that is later found to have contributed to an accident that is not an approved part is your insurance cover still valid? I suspect not.
Aviation components, even nuts and bolts, have a property called "traceability". That means that the batch of material its made from was certified by its manufacturer as tested and correct. The machines that made the part are identified and calibrated correctly. The machine operators are known to be trained and identified. The processes (eg plating, heat treatment) used are calibrated and recorded and finally the entire business manufactures its products according to a FAA (or CASA or whatever) quality manual. This costs a lot of money.
While the car companies have been into similar systems since the early 1990's (Ford Q101 etc, etc,) , in my expereince of both systems, I do not believe they go to quite the same lengths as the aviation industry, especially in the traceability area - which is why we see the occasional recall.
Having said all that, I would still be wary of replacing your "Bolt" example on the grounds that unless you know exactly what was in the designers mind when he specified the use of that particular part then you run the risk of compromising the design.
To put it another way, maybe the designer wanted a lower tensile bolt in this location so that things failed in a particular order. Furthermore, while the bolt might be a higher grade in terms of tensile strength, what about shear and bending, let alone fatigue limits? You might be transferring strains that were taken up by the original bolt's flexibility into other parts of the structure.
Sorry for nit picking, but I've made enough mistakes playing with boats, cars and assorted engines to be extremely wary of substituting parts. I've seen my share of the "unintended consequences" of substituting parts - and that includes me substituting "higher grade" parts to correct what appeared to be a designers mistake.
(a) Australian distributors price gouging.
(b) Substitution of non aviation parts.
I'm sorry to have to say this, but again, your example of a "non -aviation bolt of a higher grade" being cheaper is still a dangerous example.
Let's look at it first from an insurance perspective. If you fit something that is later found to have contributed to an accident that is not an approved part is your insurance cover still valid? I suspect not.
Aviation components, even nuts and bolts, have a property called "traceability". That means that the batch of material its made from was certified by its manufacturer as tested and correct. The machines that made the part are identified and calibrated correctly. The machine operators are known to be trained and identified. The processes (eg plating, heat treatment) used are calibrated and recorded and finally the entire business manufactures its products according to a FAA (or CASA or whatever) quality manual. This costs a lot of money.
While the car companies have been into similar systems since the early 1990's (Ford Q101 etc, etc,) , in my expereince of both systems, I do not believe they go to quite the same lengths as the aviation industry, especially in the traceability area - which is why we see the occasional recall.
Having said all that, I would still be wary of replacing your "Bolt" example on the grounds that unless you know exactly what was in the designers mind when he specified the use of that particular part then you run the risk of compromising the design.
To put it another way, maybe the designer wanted a lower tensile bolt in this location so that things failed in a particular order. Furthermore, while the bolt might be a higher grade in terms of tensile strength, what about shear and bending, let alone fatigue limits? You might be transferring strains that were taken up by the original bolt's flexibility into other parts of the structure.
Sorry for nit picking, but I've made enough mistakes playing with boats, cars and assorted engines to be extremely wary of substituting parts. I've seen my share of the "unintended consequences" of substituting parts - and that includes me substituting "higher grade" parts to correct what appeared to be a designers mistake.
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Let me be quite clear on this. I didn't sustitute the bolt for the non approved one. It was simply an exersize in econmic interest that prompted me to price both parts.
I am wholy and completely aware of the design limits intended by the designer, as I stated before, I am in the industry that deals in these things. I am also a mechanical engineer in my chosen field of employment and know what processes are used for production of certain parts.
I can tell you from experiance that the processes used for the nitriding of a cummins, cat, GM, volvo, Komatsu, samsung, nissan or whatever other company you wish to substitute, are the same as and sometime far more controlled that the ones used in a continental or lycoming. (sometimes they are even outsourced to the same companies to do). the price of a cat exhuast valve is 500% less than the lycoming valve. the cat valve is four times the size, thus having four times the material in it, has a projected life of ten times that of the lycoming one, is of better quality, and usually has a better finish and closer tolerances. is expected to perform in far harsher conditions than a lycoming will ever experiance.
AUD$30.00 for the cat valve.
AUD$600.00 for the lycoming one.
It is a blatent rip off and certainly cannot be justified other than the companies involved have a monopoly (and our regulations certainly help them in that respect) and are using it to financially benefit themselves, as are the retailers of these parts.
As much as it gives me the ****s, I still have to tow the party line and do as the regs state and pay these soul less buggers and fit the approved parts.
If one had the financial backing and the desire to, one could go through the exersize of gaining the correct approvals and produce parts of equal and better quality and sell them at a far lower price and capture the market and still do well in the profit stakes....... except the engine manufactureres have been clever and not approved the use of any other products other than their own in their engines, thus protecting their own interests and beating out any chance of competition.
Clever market protection strategies, certainly, but by the same token, very harsh on the end user. this advantage is also used by the retailers.
I can assure you that I can TIG weld an exhuast system or fuel tank as good as any aviation approved welding shop. a weld done correctly is a weld done correctly. in my workshop that same work would be done for 800% less than one on the local airfield and done faster and far more efficiantly (and from what I have seen on some jobs, done far better). but alas, cannot be done because I'm not approved to do so. can't blame testing procedures because there aint any and the insurance and paperwork to provide traceability certainly don't justify the price differance. we're just a captive market and are being taken advantage of.
I'm not saying that we should all go out and use unapproved parts/repairs/procedures, just that the industry is full of rip offs and that better can be done.
the door handle was an example of this. $400 for a cessna one and $30 for a valiant/chrysler one. same manufacturer, same part number, same part. strange enough, the one used most and broken more often (left one) was quoted at $100 dollars less than the other side. when I questioned this, the reply was, "they don't sell as many so have to charge more for them".
I am wholy and completely aware of the design limits intended by the designer, as I stated before, I am in the industry that deals in these things. I am also a mechanical engineer in my chosen field of employment and know what processes are used for production of certain parts.
I can tell you from experiance that the processes used for the nitriding of a cummins, cat, GM, volvo, Komatsu, samsung, nissan or whatever other company you wish to substitute, are the same as and sometime far more controlled that the ones used in a continental or lycoming. (sometimes they are even outsourced to the same companies to do). the price of a cat exhuast valve is 500% less than the lycoming valve. the cat valve is four times the size, thus having four times the material in it, has a projected life of ten times that of the lycoming one, is of better quality, and usually has a better finish and closer tolerances. is expected to perform in far harsher conditions than a lycoming will ever experiance.
AUD$30.00 for the cat valve.
AUD$600.00 for the lycoming one.
It is a blatent rip off and certainly cannot be justified other than the companies involved have a monopoly (and our regulations certainly help them in that respect) and are using it to financially benefit themselves, as are the retailers of these parts.
As much as it gives me the ****s, I still have to tow the party line and do as the regs state and pay these soul less buggers and fit the approved parts.
If one had the financial backing and the desire to, one could go through the exersize of gaining the correct approvals and produce parts of equal and better quality and sell them at a far lower price and capture the market and still do well in the profit stakes....... except the engine manufactureres have been clever and not approved the use of any other products other than their own in their engines, thus protecting their own interests and beating out any chance of competition.
Clever market protection strategies, certainly, but by the same token, very harsh on the end user. this advantage is also used by the retailers.
I can assure you that I can TIG weld an exhuast system or fuel tank as good as any aviation approved welding shop. a weld done correctly is a weld done correctly. in my workshop that same work would be done for 800% less than one on the local airfield and done faster and far more efficiantly (and from what I have seen on some jobs, done far better). but alas, cannot be done because I'm not approved to do so. can't blame testing procedures because there aint any and the insurance and paperwork to provide traceability certainly don't justify the price differance. we're just a captive market and are being taken advantage of.
I'm not saying that we should all go out and use unapproved parts/repairs/procedures, just that the industry is full of rip offs and that better can be done.
the door handle was an example of this. $400 for a cessna one and $30 for a valiant/chrysler one. same manufacturer, same part number, same part. strange enough, the one used most and broken more often (left one) was quoted at $100 dollars less than the other side. when I questioned this, the reply was, "they don't sell as many so have to charge more for them".
Wiz, I 'm sure you are quite right about exhaust valves and so on, but there is another factor at work - Economy of scale and also competition.
If Lycoming or Continental had the volume that Cat does the price would come down - provided, and its a big proviso, there is sufficient competition in the market place - which there isn't - yet.
So I agree Continental and Lycoming are sitting there fat dumb and happy, with the only competition coming from some very early stage diesels and perhaps possibly Jabiru and Rotax at the low end.
My guess would be that niether of the two major players has invested much in their business for decades, there simply would not be the return on investment, least of all on actually extending equipment reliability and life because it cuts spares sales.
They have simply charged all that the traffic will bear for a product with the minimum level of reliability they can get away with providing. They will go on doing so until market forces threaten their profits, at which point they will change or go under.
If Lycoming or Continental had the volume that Cat does the price would come down - provided, and its a big proviso, there is sufficient competition in the market place - which there isn't - yet.
So I agree Continental and Lycoming are sitting there fat dumb and happy, with the only competition coming from some very early stage diesels and perhaps possibly Jabiru and Rotax at the low end.
My guess would be that niether of the two major players has invested much in their business for decades, there simply would not be the return on investment, least of all on actually extending equipment reliability and life because it cuts spares sales.
They have simply charged all that the traffic will bear for a product with the minimum level of reliability they can get away with providing. They will go on doing so until market forces threaten their profits, at which point they will change or go under.
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If Lycoming or Continental had the volume that Cat does the price would come down - provided, and its a big proviso, there is sufficient competition in the market place - which there isn't - yet.
I thought you claimed to be in your element there telling us all how the price differences and exorbitant profit margins for aviation purpose parts which are just copies of some automotive ones were justified because of the increased structural integrity of them!
Well, at least you have understood the point.
520.
Continental - it's both. Low volume across which to spead the costs, and traceability and testing requirements that may very well be quite different.
I don't think you understand the concept of "fitness for purpose" which is at the heart of quality.
"Purpose" comes from the mind, experience and research of the designer.
"Fitness" is about creating an object that suits the purpose.
You may well be right in saying that a Cat valve is streets ahead of the Lycoming equivalent ata fraction of the cost.
However, I don't give a rats @rse if a CAT valve is a work of utter beauty and a Lycoming one is a dirty little chunk of steel that looks like it was made by a five year old playing with a lathe.
If the designer wanted it that way, then thats the way it gets made. If it fulfills the purpose required of it at the minimum cost, then thats great. Doing anything else to the valve, like making it a work of art is just guilding the lilly and adding to the cost.
Furthermore, just because some engineering object LOOKS great, doesn't mean it is great. You have no way of knowing what's gone into the manufacture of the object, or its testing or material without visiting the factory and having the designers and builders explain it to you.
Let me give you two examples.
I had a problem once with studs breaking in a marine engine. Ah! I say, lets replace them with high strength bolts! I did so and the following year I didn't break any studs--just totally &*^% the cylinder head. The studs were designed to break to "save" the head. Same thing on Toyota Landcruiser axles.
Furthermore, if you go inside a Landcruiser axle you will find the hub assemble held in place by two flimsy looking stamped steel 42 mm nuts that look like they were made out of old roofing iron. They look like trash compared to the beautifully hardened, ground and parkerised nut that hold the hub on a Mitsubishi Pajero, and I could make exactly the same pointless comparison as you made between Lycoming and Cat.
I don't think you understand the concept of "fitness for purpose" which is at the heart of quality.
"Purpose" comes from the mind, experience and research of the designer.
"Fitness" is about creating an object that suits the purpose.
You may well be right in saying that a Cat valve is streets ahead of the Lycoming equivalent ata fraction of the cost.
However, I don't give a rats @rse if a CAT valve is a work of utter beauty and a Lycoming one is a dirty little chunk of steel that looks like it was made by a five year old playing with a lathe.
If the designer wanted it that way, then thats the way it gets made. If it fulfills the purpose required of it at the minimum cost, then thats great. Doing anything else to the valve, like making it a work of art is just guilding the lilly and adding to the cost.
Furthermore, just because some engineering object LOOKS great, doesn't mean it is great. You have no way of knowing what's gone into the manufacture of the object, or its testing or material without visiting the factory and having the designers and builders explain it to you.
Let me give you two examples.
I had a problem once with studs breaking in a marine engine. Ah! I say, lets replace them with high strength bolts! I did so and the following year I didn't break any studs--just totally &*^% the cylinder head. The studs were designed to break to "save" the head. Same thing on Toyota Landcruiser axles.
Furthermore, if you go inside a Landcruiser axle you will find the hub assemble held in place by two flimsy looking stamped steel 42 mm nuts that look like they were made out of old roofing iron. They look like trash compared to the beautifully hardened, ground and parkerised nut that hold the hub on a Mitsubishi Pajero, and I could make exactly the same pointless comparison as you made between Lycoming and Cat.
Bugsmasherdriverandjediknite
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They look like trash compared to the beautifully hardened, ground and parkerised nut that hold the hub on a Mitsubishi Pajero, and I could make exactly the same pointless comparison as you made between Lycoming and Cat.
I'm afraid your just going to take the I'm right and your all wrong stance regardless of what anyone says........ therefore you must truely be a Guru and we all know nothing. hardly worth the trouble to discuss it.
As long as your happy in your mind that your right, enjoy.
One would have to wonder why the designers of these aero parts go through all the dramas of designing a part that will barely do the job and people that can produce a far superior part for less money, dont?. they design a part that has a TBO of thousands of hours more and is twice the product and do it for far less money. there is no secret product design features or procedures that would make it hard to make this comparison, and if you really think that there is, your just kidding your self.
you can try and justify it any way you like, fact is, its just a rip off and there really is no way it can be justified.
P.s just for the sake of the excersize, compare the price of the two nuts your refering to. you will find the beautifully hardened, faced, parkerized nut will be quite a bit more expensive than the rough finished stamped toyota product.......... not the other way around like the aviation/non aviation products I was refering to.
Wiz, I've worked for a company making aerospace parts and the amount of paperwork compared to automotive operations would surprise you.
That and the insurance and certification costs have to be offset against a very small volume compared to Caterpillar.
Furthermore, why would Lycoing go to the expense of creating a better valve, assuming one could be made and deny itself the spare part sales.
Expensive, yes, a ripoff, perhaps, but indicative of stupidity or poor design, I don't think so.
That and the insurance and certification costs have to be offset against a very small volume compared to Caterpillar.
Furthermore, why would Lycoing go to the expense of creating a better valve, assuming one could be made and deny itself the spare part sales.
Expensive, yes, a ripoff, perhaps, but indicative of stupidity or poor design, I don't think so.
I recall spending some effort in getting a bicycle grip past the flammability requirements.
I wonder what type of electrical tape your allowed to use to hold parts of your interior together
Im sure there would be a special aviation brand out there somewhere (No im not having a go at anybody)