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RFguy

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Everything posted by RFguy

  1. RFguy
    From my perspective : -Jabirus tend to have hard failures (engine stops - but usually there will have been maintenance canary in the cage warning unheeded) . Jabiru could be more communicative / proactive so people didnt find out their flywheel fell off and Jabiru knew they were falling off... -Rotaxes seem to have more nuisance failures that are unlikely to down the airplane unless they distract the pilot. (multiple carb linkages /cables for choke+throttle etc are generally trouble unless done right leaving one side rich/unbalanced), ignition module failures, behaviour of engine and richness at low gas velocities, coolant leaks + radiator expansion cap problems, oil leaks or oil pressure issues (usually due to wrong installation) , yes, both throw pistons.
  2. RFguy
    I think there is little point looking at RAAaus registered engine fail stats because there is very little data and even smaller reliable data. It's unfair to compare apples and oranges, --IE Lycomings are in majority in certified GA airplanes with strict maintenance and AD regimes and a reporting structure . -- Jabirus + Rotax are mostly in LSA or experimental aircraft with highly variable maintenance standards and program, and no AD regime and loose/no reporting structure.. in both cases, putting aside the variability of the quality of aviation mechanics, which is about as bad as any industry.
  3. RFguy
    Hi Peter Well, if you know something that could be useful to future safe (er) operation of aircraft, I'd encourage you to write to the technical manager at RAAus with any useful information . -glen
  4. RFguy
    does the ATSB have court of law style compel-to-answer style powers ?
  5. RFguy
    If I ran for RA board, driving change for the way accident investigation was done would be my #1 bullet.
  6. RFguy
    if it was a PA28 then the accident would be investigated thoroughly . I suspect part of the reason for the speculation in 4 pages here is that in general , in RAaus, the cause of an accident is never truly got to the bottom of ...
  7. RFguy
    For those interested in aircraft accidents and engine fialures, last months kitplanes article is a good one https://www.kitplanes.com/homebuilt-accidents-passing-the-engine-baton/ I would suggest a digital subscription to Kitplanes is an excellent and affordable choice for everybody who finds this article useful.
  8. RFguy
    mmm well... LSA55 - I have ~ 9 hours in them in dual, they are not lacking in power- they're quite light (240kg ish) , I would describe them as a real sports car...... I have taken off ( at Coonamble at OAT = 36 with FULL FUEL (just refueled) and 2 x PAX) and NO ISSUES with good rate of climb. even at 40 OAT should get airborne just fine, so I *guess* some other mitigating factor. compare to something like a J160 which has about the same amount of wing (and similar wing) and quite a bit heavier (540) at OAT = 38 and PA = 0, 540kg= climb = 461 fpm, 440kg - 700 fpm.
  9. RFguy
    anyway, Pilot of that Jab, if you are listening, we would love to hear the story.
  10. RFguy
    Jab's are fine. Gen1,2,3 : do not fly with leakdowns < 65/80 or CHT > 160C or EGT > (770 - fuel flow percentage). (EGT values for air cooled heads) 40 deg C, 'sea level ' density altitude is 3000' ! .... and if there was a low overhead, add another 300 feet maybe.... so performance is down about 20% ! add to this higher chances of ULP (?) fuel vapourization (was fuel pump turned on in takeoff to pressurize the lines etc ) ?? etc etc so it probably has a climb rate of 400 hundred feet a minute two up.... at best then to all that- add a thermal SINK , for example...... (OME the thing hanging out is the oil catch can)
  11. RFguy
    It's a good reason NOT to paint your Jabiru anything other than glossy WHITE - the glass temperature of the structure could be approached on a hot day sitting on the ground.
  12. RFguy
    golly you two stop it... at the end of the day, the PIC makes the call. If the PIC goes outside the parameters and limits set out in the POH for that airframe then they better be able to convincingly explain their reasoning and method.
  13. RFguy
    right. Oh well, just hope that the engine or fuel system is pulled apart by someone familiar so that what happened 1st, then what happened 2nd etc can get hypothesised. I would love to ask the pilot the 1000 questions.
  14. RFguy
    well a 3300 missing one pot can (usually) still make enough power to maintain altitude, so something might have happened that affected the whole lot (or more than one)
  15. RFguy
    airframe held together well enough, as usual... good outcome.... hope the engine is pulled apart by someone who knows what to look for what to report on, so something can be learned.
  16. RFguy
    Is the low sun going to be a factor at any end point / location ?
  17. RFguy
    thanks Nev. I will do some accurate measuring... ironically, it's cheaper for me to just go and buy a new set of pistons than refurbishing this set of 6, however, then I wouldnt get much benefit about learning the process- although I've already done that once. pressure cooker, MEK soak, ultrasonic cleaning, nylon and brass rotating brushes then finally ring lands with broken ring... that was last time, probably half a day a piston.
  18. RFguy
    I use one of those with a bit of string knoted to the middle... VERY fast to use.
  19. RFguy
    yes, always try a test piece. Dishwasher tablets- Sodium Hydroxide - deadly on aluminium. but good for cleaning up valve steams....
  20. RFguy
    Hear say is a that 100% ethylene glycol in a pressure cooker makes a great carbon remover for parts also... Carbon Chemist, what's going on there ?
  21. RFguy
    Thanks onetrack. I will try that. also, its been suggested I try selleys BBQ cleaner. Selleys BBQ cleaner will be for #3 and Supercheap carb cleaner for #4. The fronts are more gunked, the rear pots are the hot ones with the harder carbon. like I said, (last time I concluded that MEK, xylene, acetone etc which I have all wasnt really any better than unleaded petrol....). I have a pressure cooker which I clean stuff in soap, but I am not game to try 1.5 bar 120C boiling MEK etc 🙂 . Large ultrasonic cleaner isnt bad, either. given the top ring land diamond-like carbon was deposited at >250C, I cant see that coming off at much less temperature, but it's worth a go to see what the chemists come up with. I'm just remembering what a bastard job this is. (Bruce, previous engine I rebuilt was sold - this is a 310 h TSO engine I got to refurb ) . Seeing gunk in the circlip grooves is new to me. anyway, parts tank and toothbrush job for that. for me , suggests dirty oil/ oil filter not in circuit . wil check, disassemble PRV , clean etc. Filter didnt have any nasties in it.
  22. RFguy
    pistons have been sitting in gasoline for a few days. (last time I concluded that MEK, xylene, acetone etc which I have all wasnt really any better than unleaded petrol....) Observations (since this is my 2nd 6 cylinder jab rebuild) - top ring land the black stuff, the black diamond is hard, quite resistant to the broken ring tool. The #2 ring, the black gunk appears not to be hard glass carbon, more just gunk that can be pushed out within a few dozen revolutions of the broken ring tool. The oilcontrol lands are just soft gunk. brass brush/toothbrush fodder. There's also gunk in the circlip grooves, which the previous rebuild , similar hours, did not have. would be useful to be able to get the piston in the end of a large lathe chuck at 30 RPM to do some of the work for me.
  23. RFguy
    Where things become tricky and errorsom is conversion of spheroids... This usually occurs between sperical (lat long) and easting/northing etc cordinates, as , as nev says, the Earth is an oblate spheroid. and also converting from good ol' AMG66 to WGS84 or even MGA84, or even LOCAL datums. Large geo projects like the Snowy scheme have their own local datum, to better approximate the bulging earth in the region. I got to learn all this when writing radio propagation prediction programs in the 90s, having to work with all matter of map data , fortunately I had a good mate Joe Monardo who was a surveyor. We had spot height data in AMG66 or a local datum (councils had their own datums) , and I fed this into a terrain forming program called ANUS-DEM from the ANU which was originally used for catchment predictions.
  24. RFguy
    google maps you can select decimal degrees, or deg min sec, or deg decimal minutes.... OME says ": Tooraweenah Aerodrome is 31.44201S, 148.89801E , ERSA has the aerodrome at 31.2630S, 148.5400E" ERSA is DMS (deg, min, sec) . Note that the ERSA DOES NOT have any comma or decimal point. (OME you indicated that it did in your post) "312630S 1485400E" When a fix of DMS is provided, there will be 6 numbers, groups of two digits. longitude here will be three digits for deg, and 2 for min, 2 for sec.
  25. RFguy
    off topic !
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