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jetboy

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About jetboy

  • Rank
    Well-known member

More Information

  • Aircraft
    Zenair CH701
  • Location
    Omaha Flats Airfield
  • Country
    New Zealand
  1. You really need to check how the probes are attatched as well. If they are the old way, a ring around a randomly chosen spark plug, there is huge margin for error. The new Jabiru method not much better, a ring lug attached to a screw on the surface of the head. Proper way is thermocouple junction entirely "down the hole", immersed in heat conducting paste, covered over by silicone RTV or similar. If not an instrumentation error, then maybe you need to increase the baffles in the air ducts per jab installation instructions.
  2. With Jabirus, failure of the sender has been common for years. Its not to do with the orifice which is already part of the sender. Its caused by the improper location of the sender onto an oil port upstream of the oil cooler where pressure pulsations are high however the actual oil pressure to the gallery and mains (where the reading matters) is lower. If you dont want to keep replacing senders every 150 hrs then shift it to the other port available on the front of the crankcase. see where the windings are worn out due to consant movement. when the wiper fails open the gauge will read full scale
  3. Mine is a CZAW built kit, has threaded rods for the flaperon and nosegear steering parts. The plans for rods 2J and 7C1-6 are - solid threaded steel rod 5/16" x 24 rod ends are CW5-12 with jam nuts AN316-5R, except the two upper 7C1-6 rod ends get a quick disconnect (Superior linkage products SS 103) It always seemed a heavy way to do it but as the kit is designed to be built at home I'm satisfied with the tradeoff.
  4. Can the LiFePo4 battery system tolerate the jabiru / Kubota pulse type rectifier / regulator? The behaviour you are describing is typical of an overvoltage cutout system operating when it thinks the 20V or 40V spikes put out by the Jabiru dynamo (PMA) occur, which will be most prominent after the battery has been topped off from the starting and ground idle discharge period. With a standard Jabiru wiring and lead acid battery this is not a problem. The Lithium Ion battery usually has management circuitry built in. I think Powermate and / or the regulators sold by B+C Specialty for the homebuilt market are linear regulators and might be better suited. The later Jabiru PMA is rewound with double the output voltage of the original, in an effort to please the US market where they hang lots of extra avionics and the charging system doesnt work enough at idle. I dont think that is a good idea. Ralph
  5. The new interpretation / diisertation is not specific to Rotax, seems that Rotax are more affected because they have calendar items and times which most others dont. It could be very bad for 582 / 503 engines in service....isnt there a crank inspection every 300 hrs? The Microlight organisations here (at least 2 of the 3) are in discussions about it RAANZ info posted here http://raanz.org.nz/wiki/pmwiki.php?n=Main.Whatsnew Dont know what SAC are doing exactly BTW the flight permit document also specifies a new permit must be raised whenever an engine or propeller is different to the one listed. Seems they use the same form that was written for multi engine / CSU prop certified aircraft. Costs about $300. Not fun if you want to swap to climb prop for a weekend of bush flying..
  6. jetboy

    BFR in my CH701

    Mine gets better climb rate and engine cooling with flap set. I use 50kts and a climb prop running at 3200 - 3300 rpm. strut fairings made a big difference to climb rate too. yes nothing can fix a hot day with full load, in that situation I plan on a climb rate around 200 - 300 fpm, its not pleasant and even a Rotax 2 stroke would probably do better. Ralph
  7. I've often suggested a look at the Flightline 760 (ACS) as it seems to have similar features to Microair or Xcom at a lower price point. There are few of them about so quality is unknown - the first one I've seen was in an aircraft last week and they had no issues with it. Trig has a good record here. Ralph
  8. The standard setup has to be rigged with enough slack in the elevator cables to allow full right aileron deflection and then the left deflection makes the cables loose. I think the rigging instructions are deliberately vague because the simple to construct design has these issues. Another not obvious rigging situation is the rudder tensions, which need setting with the nose unloaded because the cables go slack with nose strut compression. Incidentally my initial CAA inspector was puzzled with the tightness of the cables and thought it might be due to the plane being rigged in the Czech winter and now its summer in NZ and aluminium fuse has expanded....I still laugh about this. Rather than second - guess the design I just call it a backup feature that holds the rudder firmly on - anyone familiar with 701 Hstab and rudder attachments will know I'm serious about this. If you are at the fabrication stage I'd do the mod to not have the elevator yoke rotating on an offset to the aileron tube. I've been flying mine since 2004 and the remedy to reduce the aileron bias (to the left) was to alter the position and tension of the bungee inside rear fuselage so it pulls the upper cable to the right. this by no means cures the problem just makes flying less tiresome - it holds a bit of trim tension the way that centralises the stick. Ralph
  9. I'm a bit confused about the "Jabiru return system". Apart from mate with SK who would empty the catch container to the sump as part of preflight checks. If done with a designed oil seperator, theres probably nothing bad about a return system, did Camit offer one? My 2200 would fill 500ml catch bottle about every 15 hours. A bit less often now with new rings @ 500 hrs. I have the original dipstick before Jab "fixed" the issue of blowby by shifting the full and empty marks down about 1/2" I'd rather keep the level up at least the underbelly of my plane is corrosion treated daily. I just had another pail of oil delivered, 19L cost $299. Maybe I should reconsider.
  10. a long time ago I bought Headsets inc. (link in Downunder post) ANR kits and fitted them to my existing headset. They work well and still in use, but I run them on aircraft power rather than 9V battery
  11. For a well known brand its normal. "exhaust valve opens 65 deg BBC." For a Jabiru, probably not. they usually leak throughout.
  12. I put one on my 2200 to measure the prop load vs rpm temporarily. You just remove a small screw from the middle of a port on the carb underside and place the hose there. It doesnt matter what type of gauge you use if you convert the units of scale. I just borrowed a gauge from a set of 4 carb balancing ones from a m/cycle supplier, these come with a damping valve fitted so you can remove the chatter, depending on what you are trying to use it for. they are compound gauges, not sure why for m/cycle tuning because bikes dont usually have turbos. Bought the gauges because the cars i was working on needed 4 carbs balanced - Honda S600 & H1300 Coupe
  13. jetboy

    Iridium plugs

    Bruce, If you are looking at mixture issues and the behaviour of EGT at full power, a lot of this has been covered by various Jab servvice letters, Jabbachat and finally the "manuals" My engine was a few hundred prior to the 'economy running kit' which after about 5 reissues became the production carb jetting setup today. Note that it only applies to the correct type of prop loading conditions. I spent lots of time swapping / redrilling jets as starting with OEM kit #1 it needed constant updating by factory SB. In the end I got the correct response which is a higher EGT at cruise power 2900 - 3100 rpm and a reduction of EGT from 3100 - 3300 rpm. This is very similar to the behaviour of the MS carb / O-200 my C150 had. Other than prop loading, there are a couple of things that might affect your response. The way the carb float vent line is vented (must be into the air intake after the air filter) Some jab engines were / are supplied with larger float valve seat diameter. There are different float valve spring tensions available There is different fuel pump spring tensions there is different fuel pump plunger lengths They changed the cam profiles they retarded the timing on 3300's
  14. jetboy

    Iridium plugs

    My engine (2003) and those up to about 2010 came with red HT leads which are plastic core carbon type. To be fair, the old automotive carbon leads were much less reliable than Jabs (leads) as the core seemed to be cotton wrapped carbon which would crumble out. Jabiru switched to the black leads which are believed to be inductive wire type - I havent had the opportunity to test them. I use the Bosch ferrite core helical wire inductive leads from SCA. The wire is SS and has a resistance proprtional to length but generally less than the original carbon plastic core Jab OEM red ones. Cars use these leads together with R spark plugs, but that cant be compared to the Jab setup which uses lawnmower parts mixed with a car distributor (variable spark gap right there) so I tested the voltages and spark with different leads, plugs and gaps first. If you wanted low resistance you can buy Magnecore or similar. care needs to be taken if reterminating these leads, different plug caps use diferent ways to spike the conductor. I dont know what these quotes about silicon leads are all about. Silicone leads refers to the outer insulation covering, nothing to do with the conductor.
  15. jetboy

    Iridium plugs

    Pity NGK dont make their shielded plugs BS-6E and BPS-6E in 12mm. Aircraft shielded leads are constructed with a helical wound wire core which is good RF supression without the carbon which hasnt been used in cars for 30 years and Jabirus for the last 10 or so....
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