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Bruce Robbins

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Everything posted by Bruce Robbins

  1. Hi Glen, The ends are pressed in. They can be removed if you are carefull, but I have never attempted to do so, though I have seen it done. I measure all the pushrods lengths before assembly. Assemble the heads to the barrels and torque down with NO oil in the lifters so you can compress them easily. Take note what length pushrod went you used. Push down on the rocker at the pushrod end and measure the tappet gap with feeler guages. The lifters have a working range of 3mm from memory, and I can't remember what that translates to at the tappet end. The idea is to ge
  2. Glen, It is quite a common problem. Don't risk running with little clearance. Jabiru supply two different length pushrods. Measure yours and contact them. You can also shorten the pushrods by removing the ball ends and machining the tube. I've also heard a few "clattery" Jab motors which i think have the opposite problem. Too much gap for the lifter to take up. On the last engine we did a top end on we ended up with 10 standard pushrods and 2 short pushrods.
  3. FredBBear, Jaspers Brush is closed for upgrade and will be for some time yet. Bruce
  4. Barry, Military Airspace when active is still controlled airspace. (see references quoted by ARO) So RA-AUS RPC only - No Go. RA-AUS aircraft and current PPL - Maybe. Aircraft must meet the requirements and PPL must have the airspace endorsements. R421 usually closes 12:30 Friday through to Monday morning, so is available to RA-AUS aircraft and pilots. Note that R453 is often still active on weekends, even when R421 is de-active.
  5. Hallelujah Brother. If not Oval circuit, at least the Downwind to Final turn. I believe the FAA are evaluating the proposal, or if not are being lobbied to.
  6. Jetjr, This is what I was trying to post this morning before rushing off to work.
  7. Hi Jetjr, The vane is a modified version of the cobra head fitting that attaches the scat hose to the carby mouth on a standard Jab install. They have fitted intersecting plates that run the length of the cobra head, effectively dividing the tube into 4 sections. Normally you would install the cobra head so that the outlet sits nicely in line with the outlet from the air box, keeping the scat hose run nice and straight.Because it clamps to the carby mouth you can rotate it a little either direction. jabiru cobra head - Google Search
  8. ... that's the standard Jabiru crossvane mounted at the carby inlet.
  9. Hi Jaba, We recently installed a cross vane (from Jabiru) in a roller follower J230. We found that rotating the crossvane produced large changes in EGT behaviour between cylinders. After a fair bit of trial and error we finally narrowed in to a position that gave a nice even spread in both climb and cruise. Regards, Bruce
  10. CASA plain english wording! In the Instrument the restrictions apply to Group A, which is Hydraulic Lifter (Flat Tappet) or what they called Generation 2 in the report.
  11. I have seen a Rotax 914 operating quite normally with a leaking carby bowl, but it is still possible depending on whether it's just leaking or the fuel level is too high causing flooding. I had a problem with similar symptoms on a 912 UL that turned out to be a faulty muffler. Of course that was the last thing checked, after we'd already turned the carbies inside out several times.
  12. Just to clarify, there was a flying Buzz Bomb ( R/ C), and some static models. The flying model was re-cycled, but the static models were spectacularly destroyed for the entertainment of all the big boys and girls.
  13. Classic Fighters ( this one) and Warbirds over Wanaka are similar shows, both bi- annual, but on opposing years, so there is now a top class show every Easter.
  14. We'll done Ozzie, that's exactly what is was. The strong winds on the Saturday blew the exploding fuel onto the grass, starting a grass fire that required the attentions of a couple of fire trucks. Show was very well done, as is usual for all the Kiwi air shows I've seen. Some world class displays, and plenty of " almost close enough to touch" action. If you like WWI or WWII action, then block out Easter and head for New Zuland.
  15. Camping stores or direct from the designer bluescrew.com.au
  16. Hi Happy Flyer, I can understand the icing, but how does C of G and trim affect the stall AofA ? Or are you just referring to the stick position? Regards, Bruce
  17. Just to clarify, The new Jab engines use roller Lifters, not roller rockers.
  18. G'day Ozzie, I'm probably getting into semantics, and definitely off topic, and I'm sure you know all this, but the important point to me is that it is the plane moving through the air, not the air moving relative to the ground, that makes the wing work. Quite a few students and enough qualified pilots to be scary still think of wind in respect of the ground and relate that to how the aeroplane is affected. ( " I need to hold rudder to counteract drift", "I get more lift when I turn into wind" etc etc etc) Relative wind (which I prefer to call relative airflow) is the movement of air rel
  19. Not so, I'm sure I've read something about it somewhere. :) We fly aeroplanes, not kites, so unless you forgot to remove the tie-downs, then it's not wind that makes a wing work.
  20. Sorry Aro, I type too slow. Dafydd said it better.
  21. Remember that wind tunnels are used to enable us to study and measure what is happening. In real life the air stays still and the wing moves. Sometimes it's more important to just know what happens, rather than why.
  22. ........because the leading edge of the wing has "split" the air molecules that were just hanging around together, and forced a whole pile of them to go under the wing, leaving a large area above the wing with fewer molecules and thus lower pressure. Easier to visualise if you hold the wing at a reasonable angle of attack.
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