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geoffreywh

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Everything posted by geoffreywh

  1. geoffreywh
    The inlet tract looks really wrong, from the inlet duct on the side of the fuse, then a tortuous path with scat hose causing all sorts of drag to the awful "cobra head" again with some scat hose, to a plenum of sorts (Much too small) with different length pipes to the inlet. It is not so much "why does it run so unevenly" more like "why does it run at all" I would have rather seen a 10" x 2" pancake filter straight onto the carb. With the carb heat arranged accordingly. Rotax get their air from under the cowling so it should work for Jabiru 3300? I wish the one I care for was 19- reg
  2. geoffreywh
    Daffydd...... Rotec flat slide (updraft) carby. Large tapered funnel inlet (in place of Cub type air box) with K&N filter on the front 8" cube shaped airbox with carb heat flap. I don't like the right angle in the airbox, but the ram air negates the change of direction. I Have equal CHT's and r/h cylinders 100f hotter than left!... The Rotec Fuel (" injector") would work better so much than the Bing. ( In my opinion) To the guy with the XL600 I think you are on the right track. The TBI ( very similar to a flat slide mikuni ) atomises fuel better than the Bing and Soooo much better that the Marvel
  3. geoffreywh
    Hmmm. In my quest for efficiency (0-200 - Ram air) I put the air intake just behind the prop with the filter first! Then a right angle turn into the(smallish) plenum, several more right angle turns into the cylinder, works a treat. I guess yours was just too long?.....AS far as the air having to come from the side, I would say balls to that!....
  4. geoffreywh
    OOPS! 12 0ccurences in 5 years? what , per engine? I've had 3 in 580 hours.
  5. geoffreywh
    QUOTE The valve that broke did have signs of wear on the shaft where It looks like scratching so to speak, I assume residue from the avgas, along with the pitting that you describe Dafydd. Hmmmm. Scratching is almost certainly "galling" and not from Avgas lead. It's a lack of lubricant and excess heat causing particles of the guide to "pick up" and damage the valve stem. Result is badly worn guide and poor valve life. As the guide wears the ability of the guide to lose heat lessens and ends in burnt valve ( As Daffyd so nicely explained) . I would seriously reconsider the Jab. figure of .04mm valve/guide clearance.....That's almost 2 thou, many modern aircooled motorcycle engines wear limit on guides is half that........and usually the guide material is cast iron.....Go figure.....
  6. geoffreywh
    In my experience (24hr motorcycle endurance racing) "cooling fins" on a sump just don't work, they look good but, the oil at the finned surface cools considerably , thickens and effectively forms a barrier stopping any more oil reaching the cooling surface. Fins inside the sump worked better, but not by much. We reckoned that porcupine spikes inside/fins outside would have been the best solution, but , too dear.......
  7. geoffreywh
    omg that Hurricane is just lovely. Well Done......
  8. geoffreywh
    I found it interesting to browse through this month's mag and check out the difference between the Airframe hours and the Engine hours on the (Jabiru) aircraft advertised. Looks like 400 hours is about as far as they go (with a notable,wonderful exception) without a replacement or major work... That too is my experience. My take on problem reporting? It's my estimate that less than 50% of incidents get reported, so the RAA figures will not be a whole lot of help in building a statistic base.......
  9. geoffreywh
    Quote " The reamer is to remove built up deposits in the valve guide that might cause it become restrictive and sticky and restore the bore to 7.04mm. " Just as an aside, have you tried to ream a valve guide to a thou and a half tolerance with an adjustable hand reamer? Anybody that tries that and gets an accurate size with a smooth finish is , in my book, a champion and an expert.....I believe Mr Stiff must have rocks in his head for advising that people attempt that action....K liners however can be made to have very tight tolerances. I had a head done recently in a very reputable machine shop and I was able to specify nine tenths of a thou valve to guide clearance....try that with a hand held adjustable reamer!
  10. geoffreywh
    make a triangular "doubler" riveted to the tray that helps support the tray, they don't crack after that
  11. geoffreywh
    The "Salmson" bit would refer to the pommie engine it had.......
  12. geoffreywh
    Victa, what a godawful looking aircraft, at least you can see where the design for the lawn mower came from..........................
  13. geoffreywh
    the Texans have them too, and they crack.
  14. geoffreywh
    How big is the header tank on a Jabiru? Is it full when in motion? Would that Belite gadget tell you the level is falling? I have a flag on a float in my header tank, right in front of my nose. ( it wobbles constantly so no chance of sticking) Downside? I have a lap full of petrol if the tanks bursts on a turn-over................. oh well there's always a catch.....
  15. geoffreywh
    I was about to send a blast off in the direction of people that wrote" Jabiru tank gauges are hard to read " Like , that makes it OK to run out of fuel....Then I looked up the distance between Archerfield , The planes home base, and Runcorn, The crash site ..... It's 12kms ! ..........If I assume that the flight was from Archerfield to Runcorn,........... 5 minutes???? .............. of course they could have been on a Nav ect..........I'm gonna wait quietly now for more information.........
  16. geoffreywh
    So, after reading all the posts, it's clear that this Jab engine did not fail. (surprise, surprise) OK, So why the hell did it run out of fuel? I think that I know the reason of course. The dumb PIC (who is sooo lucky to be alive) didn't put enough (any ) in. ..... Isn't everybody , before they take off , supposed to check the fuel quantity on board is sufficient for the planned flight PLUS 45 Minutes reserve. So why didn't that happen? I am so sick of blokes commiting aviation without taking it seriously, WE, who are not dead or stupid get tarred with the same brush, I get so fed up with people saying to me " oooh , ultralights? don't they crash all the time". Well, yes they do. But I don't, and many, many other serious pilots don't either. ...If you can't take flying seriously then bugger off and stop getting me a bad name.........................
  17. geoffreywh
    does he have any fuel? ( avgas only please)
  18. geoffreywh
    but who is the crash test dummy?
  19. geoffreywh
    So when does this AD start from ? I renewed control cables a year ago, following another AD. Been flying a bit since then, Who will meet me at my hangar and have a look at my work? I fly mostly weekdays, when NO-ONE is around, I checked with a LAME and he said " sure, no worries, not more than $200!" ....." Yeah right, in your dreams " was the reply......AS for the crossed control wires mentioned , how come the PIC didn't pick it up with his pre-flight check? or didn't he do that either?
  20. geoffreywh
    how can we thank him? got an email address?
  21. geoffreywh
    Thanks for the offer, I have used 80gsm cloth applied with epoxy, then filled with two pack epoxy varnish, came up beautiful.
  22. geoffreywh
    Having re-read the directive I see that I wrongly assumed that the directive was aimed at ALL maintenance, not just Flight Surfaces. My Apologies to Darren. Could be a problem finding someone to counter sign without seeing the WHOLE assembly process though... I would not be to0 happy being presented with a "Fait Acompli" and hearing someone say , "Have a look and just sign here would you?"
  23. geoffreywh
    I saw an interesting Wankel development op the net just a short while ago.................3 rotor, claimed to have fixed all the problems? But I cant find it today. Had some running as outboard engines, they had a very peculiar sound..Oh well, maybe later. Maybe on You toob
  24. geoffreywh
    None of mine! The only way engine would go missing was if someone pinched it!
  25. geoffreywh
    working on the prop so I can't fly
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