Sticker shock!

Discussion in 'Tube and Fabric' started by Cabover, Jan 20, 2015.

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  1. Jan 20, 2015 #1

    Cabover

    Cabover

    Cabover

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    I thought I might start a project, a PA-18 with my own preferences. Wider, long gear, the way I want it all around.

    My first effort was to plot out the airfoil and look into 2024T3 and 4130CrMo. Wow! Sticker shock!

    I just spent the best part of that last three years in China working with an old friend from South Africa. Former head of the Metallurgy Department the University of Pretoria now a PhD and a former university class mate of mine. I had an opportunity to do a little welding there. Their C30 was almost as good as 4130CrMo but not as easy to weld. It requires a different rod, a bit softer.

    I did some calculations on the cost of the Steel and the Aluminum for a Cub type aircraft. About $160 for the steel and $200 for the Aluminum. The prices here are at least 10 times, closer to 30 times the price in China. Their alloys for 4130CrMo are available and only slightly more costly than C-30. The 2024T3 is common there.

    So here is the question. Why are materials here so expensive? My former classmate assures me that he has tested many samples and finds few discrepancies and those usually minor. The old mode of doing business there was not conducive to repeat business. The new push is to quality and fully embracing recognized standards so as to join the rest of the world and gain repeat customers.

    So again the question. Why 20X or so the difference in materials price? A loaded container ships for about $2000. Where does the rest of the money go?

    Cabover
     
  2. Jan 20, 2015 #2

    etard

    etard

    etard

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    Stick with me here...

    Here is what you do:

    Save money for cost of materials in China, then also save enough to pay 6 employees for 4 weeks. Fly to China and stay with your friend while "superivising" the build of said desired plane. Taking pictures of build and posing for various shots of crucial points of assembly.
    One month later you return home and await the arrival of your loaded container. Problem solved! :ban:
     
  3. Jan 20, 2015 #3

    Turd Ferguson

    Turd Ferguson

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    Since China's government regulates the value of their currency, they will always be cheaper. In the US, we have things like OSHA, EEOC, Obamacare, etc, all of which drives up the price of goods and services. One unfortunate side effect of a high standard of living is you have to be able to afford it!

    In the end, all the materials in the US to build your cub airframe will run ~$10,000. You'll have to invest 1000's of hrs of labor. 50 yrs from now none of that will matter.
     
  4. Jan 20, 2015 #4

    TFF

    TFF

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    For aircraft, hopefully you are using aircraft grade materials. That requires extra testing. The Chinese 4130 in aircraft sizes has been hit and miss on quality, to be nice.
     
    djschwartz likes this.
  5. Jan 20, 2015 #5

    rbrochey

    rbrochey

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    I've always thought flying is more expensive than it needs to be. But, when you look at the history of aviation it's like everything else that the government sinks their teeth into. Basically making things harder and more restrictive than they need to be... which always results in price increases somewhere along the way. Including, of course, "aviation grade" anything.
     
  6. Jan 20, 2015 #6

    gearhead

    gearhead

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    According to this page, SAE 1020 DOM tube is 90-95% of the strength of 4130N:

    DOM Steel Tube (Drawn Over Mandrel)

    Stiffness at 29 million is the same for all steels.

    Online Metal Store | Small Quantity Metal Orders | Metal Cutting, Sales & Shipping | Buy Steel, Aluminum, Copper, Brass, Stainless | Metal Product Guides at OnlineMetals.com lists this as DOM A513 tube, offers free mill test report and regularly offers price discount of up to 20% total. Neither of these places seems to have 5/8 x .035; Aircraft Spruce has the best price I've found on 5/8 x .035 4130.
     
    Last edited: Jan 21, 2015
  7. Jan 21, 2015 #7

    autoreply

    autoreply

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    You get what you pay for. Has little to do with the government getting involved, but simply with the high quality standards.

    Usually, buying the "best" material costs less than it'll save you in being able to buy a smaller (and cheaper) engine...
     
    djschwartz likes this.
  8. Jan 21, 2015 #8

    dcstrng

    dcstrng

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    Order Alloy Steel 4130 Tube in Small Quantities at OnlineMetals.com

    Probably correct on best price -- Wicks designates (for diff in price) US/German steel v. "other," and for parts that I really want the best (spar carry-through, etc) that's what I do, but if I need a quick piece of something I often use Online because somehow their delivery rivals "Amazon prime" for speed... there have been times it seems Online must have a warhouse across the street and I live in a semi-rural area... but I've used `em all... pity Dillsburg closed, that was handy...
     
  9. Jan 21, 2015 #9

    Turd Ferguson

    Turd Ferguson

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    Many are convinced that only 4130 can be used for aircraft. Years ago, Steve Wittman told me he would still be using 1018-1024 steel, as that's what he used for most of his planes. The only reason he used 4130 on the O&O was because it was "easier to get" (whatever that means). I'm not advocating deviating from a design spec, but if the designer didn't do any structural analysis, he can't really justify 4130 on other than an emotional basis. For a ultralight or light plane --Cub type replica or even something more sophisticated like a Tailwind, I would have no issues using other than 4130.

    I can obtain 1018-1024 in common shapes and sizes locally. I'll bet most steel suppliers in any larger metropolitan area can obtain the same. It would be worth asking vs. throwing up one's hands and thinking they have to buy from one of the two "aircraft" suppliers in the U.S. I'm not really impressed with either one.
     
  10. Jan 27, 2015 #10

    TreeTopPilot

    TreeTopPilot

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    Dillsburg--charly voglesong---did sell China origin tube later on near the end of the business. Only reason I know is because they didn't offer certs for the last 6 or 7 years they sold tube....just purchased from Spruce from then on. Plymouth or German tubing....less voids to be concerned with. Something to think of when the tires leave the grass.....
     
  11. Jan 27, 2015 #11

    TJay

    TJay

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    Ha I wish airplane buyers would see this thread. Maybe then they wouldn't beat up all of us builders on our price, stuff is expensive when you do it right,
     

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