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About Subsonic

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  • Birthday 11/01/1972

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  1. Subsonic

    Who’s going to Oshkosh 2018?

    Hi all and thanks for your replies. Update: I've booked accommodation near Oshkosh, a town called Fond du lac, for four nights. I never considered camping on site, I think dad would laugh at it - not really his style. As a bonus little gift for dad, I've booked a flight for us both in Aluminum Overcast, EAA's own B17. Though I've laid spanners on a few I've never actually flown in a warbird before. Pretty excited to see what it will be like! Michael.
  2. I’ve been a member of this forum for some time, often lurking but have a long history in aviation. I worked for Qantas for over 20 years before finding my feet in other industries. Aviation in me still burns strong. This year I’ve decided to bite the bullet and get something done that I’ve been thinking about for years and visit Oshkosh. My dad’s getting older too and I am looking for things we can do together, so this year we’re going to Oshkosh! I don’t want to drop my dad deep in to avgeek land for a whole week so I’ve drafted a gentler itinerary with him in mind for a short US visit with a bit of other boy-stuff for variation. We’re also car nuts and have raced on quite a few local and international circuits so have added that and a visit to the Kennedy Space Centre too. A rough agenda for us so far is: Wed 18 July SYD – DFW 19 July Dallas 20 July Audi race experience – Circuit of the Americas 21 July DFW – FLA 22 – 23 July – Kennedy Space Centre, Cape Canaveral and Florida surrounds 24 July FLA – MKE 25 – 27 July – Oshkosh full days 28 July – MKE – DFW – SYD I’m interested to hear from you guys who have attended before and let me know your thoughts. Does anyone from Australia regularly attend this event and have any tips? Let’s try and catch up for a beer while we are there! Cheers, Michael.
  3. On top of all the points raised in the article on how this would be dangerous / impossible to survive, all checked bags on domestic flights out of tullamarine are x-rayed. The X-ray algorithm would pick up the high organic content of the bag and reject it for analysis. A human analyst would review the x-ray image and immediately reject the bag. The person who checked the bag would be offloaded and asked to open the bag. It would never make the flight.
  4. Subsonic

    The XPB Stage 1 underway.

    I'm confused now by this build. Is this now a fiberglass aircraft or are you just making skins for the metal structure you have already built? Bex, can you share the plan here?
  5. Subsonic

    Dynamic Prop Balancing

    I don't understand how this thing works either. If you have a torroid partially fluid filled, and rotate it eccentrically, the fluid will move to the area furthest from the axis. It has to, the same governor weights move outwards against the spring as they are spun, and fluid flows downhill. Sounds like Snake oil to me, but if people say they have measured an improvement to validate it, obviously I'm missing something. Perhaps there is a dampening effect due to the viscosity of the mercury in the tube? If that's the case, when the unbalance is rectified by the movement of the mercury to the light side, what keeps it there now that the assembly is spinning concentrically?
  6. Subsonic

    Why does the nose pitch down during a stall?

    With the entire aircraft descending vertically, the Centre of Gravity is ahead of the centre of lift of the entire body. Simples.
  7. Subsonic

    An RC Guys (Rotary) on the forum?

    The best training tool to learn the basics of rc heli flying these days has to be a small quadcopter. They can be had for next to nothing, and are virtually bullet proof. You will learn the basics very quickly; tail in, side in, nose in hover, forward flight and patterns, but obviously they will not fly inverted so you'll need a real cp heli or a good sim for that. If you spend a little more and buy one that you can bind to your existing transmitter it will be an easier jump back to your heli. But be careful! From cheap quads it is not too far to the vortex of FPV quad racing, so be warned!
  8. Subsonic

    EFATO incorrect meaning

    I always thought it meant Engine Failure At Takeoff.
  9. Subsonic

    Knowns and unknowns Crystal icing

    High Ice Water Content? https://www.ral.ucar.edu/sites/default/files/public/events/2015/friends-and-partners-in-aviation-weather/docs/culver-and-fahey.pdf
  10. Subsonic

    Pauline got a jab

    Australia first (and the rest of that list) is a false dichotomy.
  11. Subsonic

    The XPB Stage 1 underway.

    There is residual stress in the longerons because they are bent to shape and held there using other structure. In my experience (admittedly it's been many years since I worked on aircraft, and a very different type), a structural element was first formed to it's intended shape, then installed in the buildup. I've just never seen this type of construction before, and would guess that it would result in unknowns to determine ultimate load and fatigue life. I'm not an expert, so would need to defer to someone who is.
  12. Subsonic

    The XPB Stage 1 underway.

    I have a question on this method of fuselage construction, I hope you don’t take it the wrong way. My experience is old and probably out of date, but as a young apprentice AME (mech) for Qantas we were taught that all structural items in an aluminium airframe have no residual stress. I was never a proper “sheety” but I have seen many structural repairs and anywhere we had a longeron, stringer or section of skin repalaced it would be pre-shaped to exactly that required before fitment to the aircraft. For these types of members the material would be formed in the annealed state, and heat treated after forming to ensure no residual stress. For small aircraft, is it common practice to leave residual stress in structural members?
  13. Subsonic

    Off Topic Forum Idea

    Can you just filter the "New" posts so the OT ones don't show up?
  14. Subsonic

    Propeller safety

    Wouldn't the pull through practice best be done from behind the prop then? I guess you'd stand a better chance of being bounced out of the prop arc than if you were standing in front of it. Also if the aircraft moves, you're already behind it.
  15. That's it, I'm going. Thanks for another great podcast Adam. I've loved every one so far. I know much of what you are doing goes without thanks, so THANK YOU!!! We are listening... Michael.