Chromoly tube sizing

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Patrick Kevin, Sep 7, 2019.

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  1. Sep 10, 2019 #21

    Charles_says

    Charles_says

    Charles_says

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    Playing devils advocate.....here
    So if someone appears to be stealing they're actually guilty of theft?
    and the property owner is losing what?

    Oh wait! Don't answer that... you'd then be guilty of......???
     
  2. Sep 10, 2019 #22

    flyboy2160

    flyboy2160

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    There are tons of places online like that loop de fleur linked one that offer 'free' downloads with 'a limited free trial.' Every single one I've seen is a ripoff of copyrighted material. Some ask you for a credit card number 'just to verify', but you won't be charged until your 'free trial is over.' B.S. You get charged right away. Some are even blacklisted by the credit card companies: if you try to charge, your credit card will be declined and, if you have a good credit card company - you'll get a notification of suspicious activity. Ha! There are even listing for Femap NASTRAN on places like this. Yes, I'm suspicious of that loop de fleur listing - it's too good to be true. That link shouldn't be listed here per the guidelines.
     
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  3. Sep 10, 2019 #23

    pictsidhe

    pictsidhe

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    buildandfly specialise in selling pdfs to which they do not own the copyright. This is worse than giving it away in my eyes.

    Aerowerx's aircrfat spruce link is probably the only kosher way to get it so far. Your free link is a one of the many really suspicious sites that I'd not want to sign up to.

    So, you have posted a pirate for profit link and a probably fraud link. Those dodgy sites don't usually even have the files they clam they do.
     
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  4. Sep 11, 2019 #24

    dmar836

    dmar836

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    I will reference this thread as to why I so often dislike forums. One guy stays on topic and others try to take him down. The rest of the thread is an argument distracting from any actual on topic advice given.
    Honestly guys, it's like correcting someone's grammar during a serious conversation. Rude.
     
  5. Sep 11, 2019 #25

    BJC

    BJC

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    That is something to consider, so I just reviewed the thread. Yes, it went off topic, but only after the OP’s question had been addressed by several knowledgable people. I would posit that such flow of conversation is characteristic of people in general, not the medium, an internet forum, and not rude.

    I would expect the OP either to provide some closure, or to post a follow-up question.


    BJC
     
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  6. Sep 11, 2019 #26

    Charles_says

    Charles_says

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    I'm not bothered by the remarks of others. Everyone has a right to their opinion,
    without which, there'd be less to talk about and pick apart.
     
  7. Sep 11, 2019 #27

    pictsidhe

    pictsidhe

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    One guy had a very quick google and posted some very dubious links. One of those links will almost certainly try to rip any visitor off who tries to get the 'free' book. The other is merely ripping off the book's author.

    Why don't you try grabbing that free book and tell us how it goes?
     
    Last edited: Sep 11, 2019
  8. Sep 11, 2019 #28

    Charles_says

    Charles_says

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    Every one you've seen is a rip off
    OK Fine no one can disprove that. the rest of your statement however well meaning is
    also unprovable, since you don't list a single one that ripped you off Nor do you say that it was you that were ripped off.
    I have no idea what "Femap NASTRAN" is.
    Edit:
    OK I just looked that up. Seems that it is an software co. that deals with analytical software.
    End edit

    You are suspicious.... Hmmm I guess just because since you are suspicious,
    it is a proven bad site??? You offer no proof of your statements.
     
    Last edited by a moderator: Sep 11, 2019
  9. Sep 11, 2019 #29

    Charles_says

    Charles_says

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    How do you know this, and I didn't?
    Did you research the subject and find no permissions given? where?
    No one is asking you to sign up for something you're suspicious of.

    Where is it a proven fact, that this site is a pirate for profit link?
    offer proof to the masses!
    you offer only innuendo.
     
  10. Sep 11, 2019 #30

    flyboy2160

    flyboy2160

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    *****sigh**** So little time, so many members to put on the ignore list.
     
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  11. Sep 11, 2019 #31

    Charles_says

    Charles_says

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    Fine with me. No skin off my nose...
     
  12. Sep 11, 2019 #32

    pictsidhe

    pictsidhe

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    I started the year with 2 ignorees. I'm now up to 13. Either HBA is going down the toilet, or I'm getting REALLY grumpy.
     
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  13. Sep 11, 2019 #33

    Dana

    Dana

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    Mod note:

    I deleted some offensive comments, and also the the links to the free download site which appears to be of dubious legality.

    Keep it civil, guys.

    Note that HBA policy prohibits the posting of links to sites offering unauthorized downloads of copyrighted material. If the book is offered elsewhere on a legitimate site for pay, it's unlikely that free site is authorized... a conclusion reinforced by the weird weasel words in their "copyright" notice.
     
  14. Sep 11, 2019 #34

    kent Ashton

    kent Ashton

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    If I was going to do that I would buy some plans for a similar airplane and use what they're using. The Cub-replica plans are cheap from Wagaero (Sport Trainer, $135), Bob Barrows' Bearhawk plans are pretty reasonable. I bet you would see lots of thing in those plans that you need to consider for your design.
     
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  15. Sep 11, 2019 #35

    dmar836

    dmar836

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    Patrick Kevin, What do you think of your first post? Lol. Seriously not all threads do that here.
    Back on topic - you are quite ambitious. Without knowing your background, skill set, or education level it’s tough to know how to answer your question in an encouraging way. For a first post your question is loaded enough to imply you haven’t too much experience. Some have built successful aircraft with little or no design education but those were anomalies in an age of invention. We now know about gravity! Kidding. But I do know a guy still trying to reinvent the wheel with his homebuilt aircraft. Mostly, mashups of other plane projects and scraps he’s on about his 9th and we are all afraid this will be his last. He makes decisions everyone advises against and just won’t listen. His mistakes are obvious and egregious yet most have flown. His last collapsed when he taxied for the first time and had to be carted back to his hangar. That one later crashed (engine out and he tried to make it stay in the air) and he spent several months in the hospital. He’s back at it with a new project.
    You are not likely this type but they do exist so you might have a time getting advice. Nonetheless, some have run their designs by generous engineers who have run the numbers for them. If you are motivated, follow the early advice in this thread and set your parameters or desires and then study things similar to what you like. Even better would be to help others restore an old airplane or two(the right way) and, depending upon what you like, maybe assist with an all metal build. From there, you will have a better idea of materials used and basic construction techniques.
    Dave
     
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  16. Sep 12, 2019 #36

    wktaylor

    wktaylor

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    Duhhhh... REF my previous post... AN, AND, FED, MS, MIL [-X-XXX, HDBK-XXX, -STD-XXX] etc specs are public domain... available at ASSIST... https://quicksearch.dla.mil/qsSearch.aspx

    Other 'common specs'... AIR, AMS, ARP, AS, ASME, ASTM, AWS, IEEE, MMPDS, NAS, NASM, etc specs are managed/governed by professional/industry groups... and are 'proprietary': a licensed copy has to be 'acquired' for use within legal bounds.

    Grrrrrr... in the 1990s, as a cost savings measure, the DoD surrendered many common 'active' specs to industry groups in-lieu-of maintaining/updating them... then 'free access to the 'industry renumbered' versions went-away. racket...
     
  17. Sep 12, 2019 #37

    dmar836

    dmar836

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    I don't think the OP was asking about what various specs, names, and sizes of 4130 are available.
    Have you found all the "proprietary" names confusing in attempts to purchase or identify 4130? I have seen only clearly marked old mil spec or newer 4130 marked tubing. Easy to source. If not clearly marked I don't use it as 4130.
    Guess I'm dense - not really sure what your posts are saying r/t the original question.

    Dave
     
  18. Sep 13, 2019 #38

    wktaylor

    wktaylor

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    The OP appeared to be designing welded tube-structure fuselage... hence... there is a minimum of engineering required...

    A long time ago, I discovered, as an engineer, I had to know precisely WHAT I wanted a 'thing' [part, etc] to be made from, to properly DEFINE IT to meet MY specific needs and for future reference. This definition included 'stock heat treatments for strength' and 'stock sizes'... out of a much longer laundry list.

    When my project was for aircraft, then the material had to be aircraft quality and made/tested/inspected 'as-such'... otherwise I could inadvertently get industrial/merchant quality material that was technically the 'same alloy/temper/form' ... but NOT aircraft quality which has defined QA verification hence reliable strength and 'other' material properties.

    Guess what... a lot of what I needed to know was embedded in appropriate specs.

    Also... The reason I listed specs [that are actually within the MIL-T-] was to illustrate what stock shapes/sizes/wall-thicknesses that are [supposed-to-be] commonly available.

    Material/shape/size/temper selection for the 'designer' is often complicated... this 'uncomplicates' the process... reputable vendors can usually supply these 'stock items' without a lot of hoop-jumping for the builder.

    Here are a few wisdoms I have learned about aircraft materials and parts selection/design...

    "You deserve to get what you ask for: but if You don’t ask for very much, don’t-expect to get very much.” -- xxxx Engineer, who was summarizing his experiences with critical aircraft fastener manufacturing

    Alternate versions, by other engineers…

    "You don't get what you want... You get what you ask for. Ask carefully!” –TheTick, Eng-Tips

    "You may not get what you asked for... but [for sure!] you never get more than you ask for!” –EdStainless, Eng-Tips
     

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