Jump to content

IBob

Members
 View Profile  See their activity

  • Posts

    3,025

  • Joined

  • Last visited

  • Days Won

    26

Everything posted by IBob

  1. IBob
    I'd say that about covers it, Skippy. I tried to listen to it, but the guy has such a pedestrian and meandering delivery, I'd had it after half an hour. It seems he's trying to wander through every possible hole in the swiss cheese he encountered.
  2. IBob
    Skippy, I didn't design it. I just followed the instructions, though the al. heat shields were my own add-on. Note, though, the SS corrugated tube supplied, which allows the plumbing to be formed into tight swept bends, makes for a compact result. Makes some folks nervous, but I think it an excellent innovation. The one on the LH side goes round the engine rear and up to the back of the coolant header, and you form it in place.
  3. IBob
    Marty, my coolant radiator hoses pass quite close to the exhausts. I made little aluminium heat shields, which stand off maybe 6mm from the hoses, allowing air to pass both sides, to block and dissipate radiant heat. They are held in place by the hose clips. Seems to work......
  4. IBob

    cavalon

    IBob replied to Bilguun's topic in Rotorcraft Usergroup

    I have only experience with 912: The oil temp indicator and CHT indicators come from 1 wire sensors that rely on the engine to be grounded (0V) to complete the circuit. The RPM indicator is 2 wire, one side to ground (0V). For start I would suspect a grounding problem. Either that or a problem with the +12V to those instruments. Is the engine properly grounded to 0V of the battery? Is the 0V to those instruments properly grounded to 0V of the battery. Is the 12V to those instruments reliably connected to 12V of the battery. You will have to find a way to meter these things while the instruments are failing.
  5. IBob

    cavalon

    IBob replied to Bilguun's topic in Rotorcraft Usergroup

    Wiring diagram? Also name instruments as your pics are not clear.
  6. IBob
    I've said my bit, Nev. Sorry you seem to take it personally.
  7. IBob
    The problem with lagging the fuel lines is that if they nevertheless become heat soaked, the only way to cool them is by running fuel through. Blast tubes of cold air only work once you're running, and if you are heat soaked, the problem is already there. It seems to me that most engines......most things.....contain compromises. Rotax certainly have those compromises, and in the case of the risk of vapour lock, I think they found a simple neat solution (albeit easier to build in than to retrofit).
  8. IBob
    Why is using fuel to remove heat hardly a good way to do things?
  9. IBob
    Cannot now recall, Marty, but that sounds about right: whatever fits at both ends.
  10. IBob
    Skippy, I've been close to having a quick brown myself.......but more normally when flying.........😬
  11. IBob
    All good points, and I wouldn't suggest it is without it's drawbacks. Fortunately on the Savannah there are sight glasses on the inboard tanks (which is where the standard return goes to, RH). And I can report this, on several occasions: Prepare to start cold engine: Turn on aux fuel pump, which runs at steady rate, watch fuel pressure rise > 2PSI. Turn off aux fuel pump, watch pressure fall (return line is clear). Start engine etc and fly. Land, taxi stop engine. Prepare to restart warm/hot 5/10/15/20mins later: Turn on aux fuel pump, which runs very rapidly for 5-10secs, then runs at steady rate and fuel pressure finally rises. Presumably expelling vapour via the fuel return (and carbs): vapour will pass through the return orifice much faster than liquid fuel, hence the rapid pump activity to start with, then the steady pump rate once all vapour is gone. I have had this on a number of occasions, and I think it a very good feature in this type of aircraft. I would still not take off immediately, but I would say it goes a long way towards avoiding EFATO due to vapour lock.
  12. IBob
    How so, Nev?
  13. IBob
    Marty, same size as the fuel return line orifice. I think we decided that is 0.35mm or thereabouts.
  14. IBob
    Thanks Skippy. I have a Facet Cube and no external bypass to that, so the Cube must allow free flow when not running: at a guess (and it is only a guess) perhaps when powered off the internals park themselves so as to allow free flow? A minor detail with reference to your above diagram: ICP run the fuel pressure gauge via a small orifice, same as the return line. Presumably to limit the amount of fuel dumped in the cockpit if the gauge or plumbing spring a leak(?)
  15. IBob
    A sketch/diagram would probably help the conversation here. I don't understand how non-return valves would enable each tank to be emptied , with no risk of air. And I don't know what sort of non return valve allows free flow in the forward direction without a throttling effect: in water reticulation, that would be some sort of swing valve, which relies (in small part) on gravity and must be installed right side up. Is there another sort of valve, more suitable for aircraft use?
  16. IBob
    Does the booster pump not have an internal (non return) bypass, or some arrangement that provides that function, Skippy?
  17. IBob
    VC-121A 48-0614 Columbine, the personal transport of General Dwight D. Eisenhower, on display at the Pima Air & Space Museum
  18. IBob
    From Wikipedia: "Among the types of aircraft that have been used to investigate hurricanes, are an instrumented Lockheed U-2 flown in Hurricane Ginny during the 1963 Atlantic hurricane season. Other types include the A-20 Havoc, 1944; B-24, 1944–1945; B-17, 1945–1947; B-25, 1946–1947; B-29, 1946–1947. WB-29, 1951–1956; WB-50, 1956–1963; WB-47, 1963–1969; WC-121N 1954–1973; WC-130A, B, E, H, 1965–2012." They were the WC121N, a military version.
  19. IBob
    A strong aircraft too: as I recall the US met. people had a beefed up version that they used to fly into storms to gather data.
  20. IBob
    Harold the Helicopter....as featured in the Thomas the Tank Engine books....) Westland Harold???
  21. IBob
    What a beautiful aircraft they were! My folks took me to Heathrow as a kid to watch them come and go.......)
  22. IBob
    Another potential indicator is the very round numbers: almost nothing costs exactly $9500 (though in this case nothing does!) Somebody recently tried to hit me up for a very small amount of bitcoin I hadn't purchased: the cost was to be exactly 300pounds....
  23. IBob
    I was tempted, sometimes a lot, during my build to 'improve' the design. I resisted by telling myself that there are probably thousands of these, built according to manufacturer's instructions, and they work fine. Then, sometime after the half way mark, all I wanted to do was see air under the wheels, so I took the shortest route to that and just followed the instructions. Or tried to (we all have moments with the manual!) And in retrospect, I think you could count on less than one hand advisable improvements to the kit and instructions as delivered.
  24. IBob
    That is the 'newer' bellcrank arrangement. My kit, factory dated Dec 2014, came with the old quite different version, but the instructions for what you have there. So it changed about then. I would think that if there were wear problems we would have heard by now. My thought is that, while the bellcrank is constantly worked, the movements are for the most part very small. And assuming the bellcrank pivot is at 90deg to the pull of the elevator cables, there would be minimal pressure on the side faces. Having said all that, if you have the means to shorten the tube and add a washer, why not?
  25. IBob
    We don't generally chew on our stick grips much round here..........
×
×
  • Create New...