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rgmwa

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  1. rgmwa

    Lockheed SR-71 Blackbird

    rgmwa commented on red750's aircraft in Military

    I read somewhere that they couldn’t fly it these days, mainly because the fuel it used is not obtainable any more.
  2. rgmwa
    Which one?
  3. rgmwa
    Spin recovery is one thing but letting go of the stick in a spin and hoping it will self recover, which it might eventually, is not something I’d like to rely on, particularly in bad weather.
  4. rgmwa
    I'm not so sure. Maybe if it was very well trimmed. I've only flown an RV-7 once so I'm hardly well qualified to comment, however it was a bit more sensitive in roll than my RV-12 and I wouldn't trust that to recover by itself as it rolls and accelerates downhill so easily.
  5. rgmwa
    Well that’s still a pretty good endorsement even if you don’t end up buying out GE and P&W.
  6. rgmwa
    Thanks for the update. Very interesting to hear GE and P&W obviously taking it seriously. Hope it’s a winner.
  7. rgmwa
    I assume the engine was on display at Oshkosh. Did you get a lot of interest?
  8. rgmwa
    I think the shock of witnessing a crash like that makes people react in ways that may not seem logical. There is a chapter in ‘Fate is the Hunter’ where Ernest Gann describes he and another pilot in his parked jeep freezing after seeing a DC3 crash and start to burn in front of them. He struggled to understand his own reaction and it had a profound effect on him.
  9. rgmwa
    Tragic accident. I had the seat slide back in a 172 once. Luckily it happened early in the take-off run, so I aborted without problems apart from upsetting the tower by exiting the runway without asking permission.
  10. rgmwa
    The Odyssey PC680 is the standard battery Van's supplies with the 912ULS for the RV-12, but they supply the much lighter Earth-X (0.6kg) with the RV-12iS because the engine is heavier.
  11. rgmwa
    PC680 weighs 7.0kg.
  12. rgmwa
    I use an Odyssey PC680 AGM with my 912ULS. It's about $160-$190 from various retailers.
  13. rgmwa
    Like Morry Hummel, Vans have over time incorporated improvements in the RV-12, and no doubt the other RV models, based on suggestions and modifications made by the early builders and documented on Vans Airforce website. Even yours truly can claim a couple of very modest contributions that have since appeared in the current kit.
  14. rgmwa
    Agreed Onetrack. I've read the Silver Centenary story and also had a good look at it and watched it fly more than once. It's hangared at Serpentine, where I keep my plane. Ford did a remarkable job - it looks right and in engineering, that's usually a pretty good guide as to whether something is right. And as you say, just because an aircraft was `professionally' designed doesn't mean that it's going to be any good. There are plenty of examples of professionally engineered flying crocks in the history books. Nor does having formal engineering qualifications make you a gifted designer, just as having no formal training doesn't mean you can come up with an excellent design. I learned a lot about aircraft construction from assembling (I won't say building) my kit, and am currently one of the mentors helping a bunch of high school kids put together another RV12. My own preference for a plane that I and others are going to fly in is a kit from a reputable manufacturer, but I'd also be happy to build off plans if I had the time and the right equipment. It's just a lot more work. If I was going to design my own plane, as I said previously, I'd want to make sure I'd done my homework to know what I was doing. In engineering, it's knowing what you don't know that keeps you out of trouble. So far, so good.
  15. rgmwa
    Yes, I’m happy to build and fly a plane that I know has been well designed and tested, and to make relatively minor modifications that I know won’t its airworthiness. Nevertheless, even though I’ve spent the last 40 years designing structures for a living, I’d still think twice about tackling an aircraft without doing a lot of homework. Hats off to the true experimenters though.
  16. rgmwa
    It’s not the ‘design by eye’ part that would would worry me. It’s the ‘confirm by test’ bit that would make me think twice about buzzing around at 1,000 feet to find out which part of my design needed improving.
  17. rgmwa
    The struts are not very long which is good, but I'd suggest "When in doubt, make it stout!"... especially when your life depends on it and you're not sure what the loads are. There's a big difference in strength and stiffness between 20 and 25mm tube for the same wall thickness, and steel is a lot stronger than aluminium (obviously). Also if you're putting bolts through it, the bigger tube will lose relatively less cross-sectional area.
  18. rgmwa
    How long is the strut?
  19. rgmwa
    I agree with Yenn. You need to have a pretty good idea of the tension and compression forces in the strut and its fittings under all loading conditions, and also how to design in timber if you're not building from a plan.
  20. rgmwa
    The highest grade I found for seasoned hoop pine after a quick search was F17. It's a softwood and AS1720 (Timber Structures: Part 1 - Design Methods) - gives a characteristic bending strength of 42 MPa and tensile strength parallel to the grain of 22 MPa for F17. However, these basic values need to be modified by a whole lot of factors if you want to design something.
  21. rgmwa
    I don’t think it’s racist to notice difference. It’s obvious that people from different places and cultures have different characteristics. The problems start when those differences result in differentiation and discrimination. We have many different races and cultures here in Australia, but compared to many other countries like the US, we do remarkably well in creating a pretty homogeneous society. I’ve always thought the Australian accent is a great unifying factor in smoothing out cultural differences over time.
  22. rgmwa
    I wonder about the Wandering Albatross. They spend many weeks flying day and night over water and you would think they might get caught in IMC. Even night flying would be tricky. I suppose they could land but taking off from rough water wouldn’t be easy. Interesting question.
  23. rgmwa
    Good news! Looks like overseas travel is back.
  24. rgmwa
    He makes it look easy. I spent some time watching one of these in action on the North Island a few years ago. It takes a lot of skill fly one of these in that hilly country.
  25. rgmwa
    Looks like those South Africans are in business for the long term. Good to see. Anyone know what a Sling 2 kit costs in Australian dollars?
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