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RFguy

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  1. RFguy
    any idea how to access the GAF and NOTAM archives ? You dont depart canberra without talking to ATC on several occassions , would they have had something to say ?
  2. RFguy
    good catch that Chris on the 3600' decent, --but given the reported speed was a long way below the Va, a sudden and extreme control input would only cause a stall. The weak point in the data we have here is that 1) we only have ground speed, 2) The data is sparse in the time domain, relative the the rate of the events. Maybe he was flying 140 indicated and only 110 ish ground.
  3. RFguy
    Hi Mark, I would think unlikely to be structural failure, at least not the first cause, Va is 133 kts and Vchute is 133 kts. Maybe icingand or flight into IMC, then LOC, and too fast for the chute to be pulled. It was very moist at altitude in that region. yesterday, there were thick and dark cumulus allover that region. But given 3 kids lost their lives in an aircraft that should have been very safe, I am hesitant to speculate much further. We'll need to read about it.... As a parent I can only just imagine what the nightmare must be for others....\ Coming back- RAAUS go on about 'flying is so safe , a pilot in everyhouse' which I think is bollocks, flying is inherently hazardous.
  4. RFguy
    https://www.flightaware.com/live/flight/VHMSF/history/20231006/0330Z/YSCB/YARM/tracklog Many permutations and combinations : Pilot incapacitation ? Flight into IMC and rated / IMC current ? (they all have autopilots) In flight fire ? Parachute not successfully deployed (too fast?) Structural breakup (flying over Va in severe turb) ? Va is 133 kts for at least one SR22 I POHed. at 3400 lbs. That's ~ 127kts at my estimated weight. Stall clean is about 70 kts. autopilot disengages in severe turb.... so if you are in IMC AND severe turbulence, that's a non autopilot combo. https://jasonblair.net/wp-content/uploads/2015/06/Cirrus-SR22-POH.pdf
  5. RFguy
    I think MGL is always a good option, they do listen to their customers, also. Maybe can take a look but we're along way from that yet, lots of things still to check. My guess is vibration related. Oh, BTW though WHAT is the 12V bus voltage at 1000RPM, 1500 , 2000, and 2300RPM ???? I've seen a regulator putting out excessive voltages causing voltage spike protectors start to act and putting lots of noise on the 12V...
  6. RFguy
    Nice airport, good tiedown points (lots of them), nice aero club people. Did my usual 120KTAS each way@ 31.5 lph.... Rex was changing a turbine in a saab in the hot sun.....
  7. RFguy
    The only reason I would be hesitant of that size is that you want to make sure it is not being SWITCHED IN. IE it's always across the bbattery and NOT being switched by a contactor . Why? Because a capacitor that size will be a infinite current sink when power is applied- this will tend to lessen the lifespace of any relay contacts or switching contacts. IE a bad idea. Also if there is a fault condition, the capacitor will be ablwe to supply zillions of amps (briefly) . So, suggest avoid using it. If there is alternator noise, that will be some different problem. Some instruments are suceptible to noise, and this should have their power supply LC line filter. You WONT get static like being mentioned here for any likely Jab reason . glen
  8. RFguy
    and if you fly with a Jabiru engine , you are absolutely completely nuts flying without CHT/EGT - a failure will be just around the corner....
  9. RFguy
    Unless you have a sick Alternator Regulator, I dont think it should need the capacitor. Well, I had a colleague the other week and was IDENTICAL symptoms- and it was the connector.... I'd be looking there. TX was fine. Loosening the screws can tell you if you have some sort of microphonic in the radio. BTW when you say "It's a screw in antenna. Antenna is in the tail fin." - Jabiru factory dipole antennas in the tail are not screw on antennas- what are you referring to ?
  10. RFguy
    So, improved technique on the weekend's trip to Broken Hill. Didnt pee on myself. Pee into bottle, then decant into larger master bottle. Although at BH, I needed a drink on the ground and took a swig from the wrong bottle. wont do that again. I hadnt decanted the 2nd pee. from in-situ to master bottle. To prevent that , ont he return I immediately decanted the in-situ bottle.
  11. RFguy
    right, back from my latest weekend YBHI adventure. Antenna ground plane need not be earthed. Since I have a Jabiru and I 'wrote the book on radio' :, please answer the following : 0) Check the connector on the antenna for tightness (BNC bayonet locked) AND what sort of connector ??? - recently I found someone has a right angle adaptor between the radio and the antenna plug- this right angle adaptor wasnt the best and caused reception breakup > 2000 RPM ! (bad connection) . Remove adaptor ! If you need right angle- use with a right angle plug , no adaptor 1) Which antenna is this radio connected to- the antenna in the tail, or the antenna before the rear bulkhead ? 2) To your knowledge , are your transmissions affected ? 3) Have you tested what the VSWR is of the antenna ? 4) Can you physically vibration decoupler the radio from the panel- just loosen the mounting sc rews a couple of turns - does the problem still happen ? that's a start.
  12. RFguy
    so, back to Broken hill this weekend. armed with a bigger bottle. Seems I was very lucky last time to have a tail wind both directions (east to west, west to east). I see now , there's about a 2 day window in 7 of east to west winds. Quite interesting what goes on at different altitudes, at least in the models. al least coming back, I will have 30 kts behind me...maybe more . that will make up for the 10-15 kts headwind outbound. 105k indicated will be just that in ground....
  13. RFguy
    hey what happened to my thread
  14. RFguy
    be sure to remove the varnish off any (rotating) shafts, also. replacing o rings etc, one can forget cleaning the things that run through them .
  15. RFguy
    some engines are good for no-lead, some are not. many have had no-lead suitable seats and guides fitted during overhauls in their 50 year life span.....
  16. RFguy
    It is a good point about water freezing in the fuel lines, Nev. Fortunately, the Piper has good fuel sumps and I've never seen any water in them ever. (never say never ) . It's certainly always below 0 up there. Good point also about wing skins being cold. If I descended through a humid region, or cloud, that's something to consider. I still affirm for long pt to pt flying , flying low is TAS on the table. (FL125 is 123 kts TAS for 100 knots indicated which I can do) Interesting though what happens with the east west winds up there, going west, almost always better being down at say 8500 or 6500 with the headwinds. 8500 is a reasonable compromise. up high, bumps are less, radio coverage is better and options are better for engine trouble (unless u have a fire...) glen (PS: left tank always AVGAS and used for TO and landings, right tank ULP98 when available outbound)
  17. RFguy
    Thinking about this, so many unknowns what is the existing intercom type and how has it been wired to the radio ?
  18. RFguy
    Mike are you sure you just didnt leave it in the seat back pocket?
  19. RFguy
    I wonder if a pre-built / wired harness is something that should be considered. there really isnt much to it. Otherwise labour costs in plane are not insignificant. Shajen, you can ground run the jabiru, just watch the CHTs. Don't let them get over 150C on ground . If the idle is set correctly, there is no problem ground running most Jabirus, but it wont charge the battery at that RPM. Do you have CHTs on all cylinders? If not, forget flying a Jabiru until you do.....
  20. RFguy
    using the internal trig two place intercom ??? wired up the headset wiring correctly? not using shorting jacks ? "radio guys" ALWAYS sit in the plane with them running , up to full RPM and see how it goes... OK overall sounds mainly like a connection problem to the headsets, or some issue with the way the headsets are wired Please post a diagram of how it was wired in the aircraft IE as built. If you do not get this, do not pay the radio guy. glen
  21. RFguy
    Hi Nev and I have learned this.... I knew it might be a problem, ffrom calcs - and so it was.... and it was a warm day.... The math said it would be a problem somewhere over 11,500' PA, and it was when > FL120.... at a PA of 12,000 feet, the air pressure is 65 kPa, WELL within the MOGAS RVP seasonal range of 55 to 80 kPa...... (avg approx 65kPa at 35degC) AVGAS is 40-50. so, if the air pressure was the same as the 35degC RVP, it would not take much suction to get vapour. (noting that the RVP reduces substantially at lower temperatures lessening the issue as you pointed out Nev with cold soaked tanks) . Not seen any issue at all at FL115 so far. Note that some manufacturers have wider ranges of RVP of their unleaded petrol than others, for whatever reason. BP says 30 to 100 (20 deg C), Shell PULP98 55-80 (37.8C), United98 27-80 (20 deg C). here are a collection of datasheets. Probably a good reason to avoid leaving MOGAS lying around, also, since the suppliers increase the vapour pressure for winter. (dont use it in summer) Fuels, Safety Data Sheets, Suppliers - Dry Lakes Racers Australia WWW.DLRA.ORG.AU The official home page of the Dry Lakes Racers Australia
  22. RFguy
    Don't forget high altitude vaporization of MOGAS not just hot weather. So, do consider the need for the boost pump.. AND consider large diameter fuel lines from tank to pump to reduce suction tension (low pressure) which will promote formation of vapourization bubbles for high vapour pressure fuels (MOGAS). Keen readers will be aware I calculated that MOGAS might get bubbles in the fuel lines once over 10,000 feet, depending on summer or winter gasoline, and sure enough at FL125 the other day, (actually climbing through 11400 feet (slowly ha ha ) - fuel pressure began fluctuating a little periodically (bubbles passing) and slight EGT variations. Switch over to AVGAS tank, no problem..... drop back to 8500, back to MOGAS tank, no problem.....
  23. RFguy
    And also consider an airplane pitched for a student might be different to for a seasoned pilot. That is to say, maybe do not pitch the prop too fine such that the student is having to continuously be concerned with the engine overspeeding when the primary objective is to learn to fly the aircraft. IE might be pitched for 5500 WOT best climb to give the student some breathing space (but leaves some performance on the table)
  24. RFguy
    For something like the rotax , for a prop pitched for max rpm at best climb, we control climb RPM at WOT by pitching up the aircraft and slowing the aircraft down and prop RPM falls to within limits. Generally we do not fly at WOT when S&L , this would mean an overspeed. If you operate out of restricted ALAs, I would be pitching it for MAX RPM (5800) at best climb . That is what matters most when you need to clear the trees. You could also pitch for 5800 at best angle (usually slower) but might mean you overspeed at 75% cruise in S&L but that will depend on the airframe (drag behaviour) and the prop . IE how much faster cruise is. If you pitch for 5500 RPM at 75% S&L, you might be leaving some climb performance on the table , that depends on the difference between best climb and your 75% cruise speed. If there is not much of a difference, then pitching for best angle might still mean you dont overspeed at 75% S&L. BUT Different props will have different airspeed behaviour.
  25. RFguy
    but Mode S and ADSB are supposed to coexist (if your modeS doesnt have adsb , or are you saying your mode S transponder HAS adsb ? anyway, you can look for that hex code on the sites...
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