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About skippydiesel

  • Rank
    Well-known member


  • Aircraft
    ATEC Zephyr
  • Location
    The Oaks
  • Country

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  1. Hmm! When I do a shut down mag check on a LyCon its to determine that there is a good earth (dead short). Rotax 9's have have an inconsistent (rough) low speed idle at the best of times and wouold seem to be sensitive to seasonal temperature variations - not sure that an idle speed "mag" check would give you much information.
  2. Possibly, however rotations (cycles) are roughly double, so even if your statement is correct everything else that is experiencing friction, erosion, cyclic impacts is happening twice
  3. Thanks for that Aro, I think I follow - quite the educator BUT this still does not quite explain away all my concerns; Low engine speed results in sub optimal spark timing, less than optimal fuel air flow/mixing/combustion (volumetric efficiency), low oil flow/pressure and coolant flow. Perhaps I am too focused on ground based engines however I have always understood engines to have a optimal RPM range and that low speeds (for a given engine) are not good for longevity. Contrary to the old expression "revs= rebores" (American propaganda ?) engines that are designed to thrive at hi
  4. Nev I understand "limited" In this context includes - load & duration/time. I agree that airframe characteristics come into it. Operating below optimum may also be below or at max torque; The analogy I would use (perhaps not perfect) - its a bit like doing 90-100 kph, in overdrive, with minimal load/passengers, on a level road - all well and good as long as the gradient remains level (constant relatively low load). Great fuel econamy, engine only lightly loaded BUT add a gradient/stiff head wind/towing/acceleration (ie increase load) and it will probably be easier
  5. I suggest that it would be impractical for Rotax to develop a similar graph for every density altitude or even for blocks of altitude so they have come up with a fairly frequently used altitude ( "pressure altitudes below 3500ft") to illustrate their recommendation for engine management in this area. I quote: "Continuous use of engine speeds below 5200 RPM must follow the manifold pressure graph below" which then has the words (in the shaded area below 5200 RPM) "Limited operation in this envelop area" I dont know what this means to you however I like to be "kind" to
  6. Shame on you. You just took the fun out of the debate😊 As most Rotax 9 operators know & the graph you have provided proves, the recommended sustained operating range is 5200-5500 RPM - unfortunately the end of the story/debate
  7. I may not have the tech training/experience of Nev but I do know that no engine likes to "luge" under load. I am using the unscientific word like to summarise all the negative impacts/behaviours of an engine operating in a RPM band below its optimum when under load.. There is unlikely to be any ill effects from operating a Rotax 9 being operated below its optimum RPM range, when lightly loaded however I would class this as more like a "loitering" condition rather than cruise
  8. Hmmmm ! $1k for a recovering sounds very steep. I had my existing foam seats, on my last aircraft, recovered in very nice leather (the real stuff - not a painted finish, like most upholstery leather), as per old English sports car style for $700 for the pair (6 years ago). Faux leather can be superior to the real deal - Mercedes had a leather look alike upholstery product they called MBTec in some of their lower end sedans. It was so good a lot of people thought it was leather. Turned out to be longer lasting more breathable (for the body) than leather.
  9. Car front/bucket seat option - Of course there will be remodeling but if the basic construction of the foam is right then it should be possible to trim to shape (including stick hole/slot), get the resultant cushions recovered (professionally) and "Bobs your Uncle" - OR is this just fantasy? Qld wreckers would seem to be more $ reasonable than the greedy Greater Sydney tribe. Back to "Contour" cushion - sounds like you had at least the bottom/base cushion built to your particular dimensions - is this correct? How did you determine the correct (for you) thick
  10. The way I see it a small passenger say 50 kg - so replacing passenger with a 40 L fuel bladder plus transfer pump, is going to be well within your aircrafts capability - expect to pay about $2k from Laszlo at Turtle-Pac. His larger bladders have a umbilical like filler hose but not the 40L - might make filling in aircraft a problem/conversely filling befor loading a strain on the old body
  11. Yeah! - I had a ride in a Subaru at the weekend - very comfy seats. Why didn't the car seat idea work out ? (might save me a lot of wasted time & $$) I was given a memory foam mattress - probably a bit thicker than 100mm - heavy as - but sooooper comfy. So Contour is a name of a product not a description?
  12. I confess to having no experience/idea of trike's and their particular characteristics BUT I do have an idea of what the Rotax manuals say on the matter and your figures would appear to be outside the recommendations. Fuel burn is but one measure - most engines have optimum engine speeds, particularly those that are expected to deliver high continuous power (aircraft, pump, generator, tractor, marine applications). The engine speed is not just about power but also things like, lubricant reticulation, coolant speed/flow, removal of heat, torque delivery, reserve torque, etc etc.
  13. I just love the way the car drivers went around the aircraft - no hazard warnings lights - no help - just went on by as if this sort of emergency is an every day occurrence requiring no response (dont get involved) - quite the documentary on human behavior.
  14. Ooooh! very nice - its provably just the photo but it looks like the passenger gets a flat back. Q. Memory foam is heavy and 100 mm is particularly heavy. I am exploring repurposing front seat cushions (already contoured) from a number of Japanese cars ($200-400/pair) - if works just need recovering
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