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jetboy

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About jetboy

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    Omaha Flats Airfield
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    New_Zealand

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  1. 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.
  2. jetboy

    Headset upgrade

    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
  3. jetboy

    Engine Exhausting

    For a well known brand its normal. "exhaust valve opens 65 deg BBC." For a Jabiru, probably not. they usually leak throughout.
  4. jetboy

    Vacuum Gauge

    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
  5. 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
  6. 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.
  7. 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....
  8. jetboy

    Iridium plugs

    I have been on R plugs in my 2200 for 12 yrs - ever since replacing the original resistor carbon leads with the inductor type. This was done to reduce the radio interference that Jabs are so well known for. Extensive testing with lab equipment showed no change to the loading or stress on the coil packs or any other part of the system. The coils are for Honda lawnmower engines and have a resistor plug or resistor integrated cap depending on market. I never clean the plugs, just replace at 200 hrs. They are gapped to the Jab setting as these are standard plugs. This would more than make up for the perceived effect of the resistor. In reality the resistor doesnt lower any voltage to the electrode because there is no current flowing at the time - see scsirob post If I were to fit Iridium, I would leave the gap at the wider setting its because the spark threshold voltage is lower to break across a pointy end. Next plug change I might get Iridium, but the cost benefit is not great if I'm getting 200hrs on regular plugs
  9. jetboy

    shark fin antenna

    Pilot dentist buddy X-Rayed one. What you see is the film taped to a window, hanging in the conventional way. The guts of the thing appear to be the connector centre shaft coming down, soldered to a flat perforated pice of metal, roughly the shape of the outer moulding. Radio is a black art, what we see doesnt allways look plausible. GPS patch antennae are another mystery.
  10. jetboy

    shark fin antenna

    this is what the dentist saw
  11. jetboy

    shark fin antenna

    No, they are more robust and expensive. The cheapest version of stick and ball are prone to breaking when washing the plane.
  12. jetboy

    Which Engine???

    only new (gen4) for the Jabiru, but postpone this decision until there is an established track record. you could safely choose a timex 912 and just overhaul the gearbox, they have a good record and flight schools often renew them rather than overhaul. the D-motor is my personal 1st choice, it comes down to price and that depends on the country. In my case, the existing engine mounts are for Jabiru / D-motor / ULpower and that represents a big difference. The ring mount for the 912 is pricey but essential and adds to the cost.
  13. jetboy

    Which Engine???

    Although the OP is 12 years ago I'll add to the discussion My 701 was built in 2003 and the engine I wanted to try was Diamond AE110R (ex Midwest Rotary ex Norton design) This engine never made it to production so I chose the Jabiru 2200. Other posibilities were Hirth 3701,, Konig MZ301i, Simonini Victor2, Rotax 618 or 582 or 912. Note that for my build of the 701 modifications are required to the rudder / tail attachments to use the 912S) There has been a 701 in NZ built with HKS, changed to Corvair, changed to J2200. I wrote the owner who said the Corvair was great power but too heavy and thirsty rendering it a 1 seater for any distance Another started with BMW, then Rotax 532, then EA81. I rode in the 532 version and it performed well. The 701 design started with 503 One has an EA81 with weights in the tail and reportedly didnt handle that well according to newsgroup questions from the owner Another has a geared VW which overheated but believed to be still flying on the rebuild One had a Simonini which didnt stay on long, believed to be 912 now, as are the rest of the 20 or so fleet. All the 2 strokes have a poor reputation in NZ the 582 being the best prospect with a 300hr TBO - most do well over 600 without trouble. Today we have some other choices My solid lifter 2200 has done 550 hrs now with new rings (a known issue with pre - 2006 builds) its doing OK if it gets to 1000 I should be happy. If not I have put a label on it DNR (ask a paramedic) as if anything major breaks there are not worth rebuild and they are onto Gen4 production now. I would not consider a used 2200. There is not enough track record on the new ones. D-Motor is my favourite prospect although there has been 1 failure around the head sealing. I dont do high hours so a 582 is still a good option. Heavy airplane is not happy airplane. The 701 doesnt need more power. Get a 750 or 801 for that role.
  14. Jab7252, Its a useful project and I would probably use it in place of my failing constellation of GPS Currently I have to fallback to a Garmin90 because the last 3 GPS3 Pilots have all packed it in, the 90 display is similar to what you have and supplies situational awareness with distance and bearing to any selected waypoint. I carry a paper map but like to be able to give accurate position reports For day VFR, on a small screen mapping is not helpful - with the GPS3 I would turn off all the airspace, roads etc. so I could see where I was going..... My plan was to use a discarded smartphone (starting with Android 2.3 Gingerbread) but I havent been able to find a navigation app that is free / not trial /no ads that will do the job of the early 2 dimensional GPS style. I would attempt it myself but never seem to have a PC with enough power to install the emulator / ADK required. The reason I keep things free is there is no ongoing obligation to update (both from the developer and user perspective) and often apps that look like they will be suitable, are not so become a drain on time If you have a blog detailing how you go about this I'd be interested too. I can compile in Fortran77 but its hard to start into app development when the tools dont have clear instructions to get started Ralph
  15. jetboy

    Inaccurate aircraft performance

    Dreamers should do their own research, however there are a few common misunderstandings about performance figures etc. For instance, Dynearo might get more from a Rotax 912 because they use a custom muffler All the Zenair line have airspeeds qouted as IAS and if you read the construction plans there is no external static pressure port..... gives better readings 5 - 10 kts USA planes often quoted in mph - sounds better than the kts version Takeoff / landing distance done at less than MAUW, without 50' obstacle clearance distance, grass or paved surface not quoted. these are all 'legitimate' sales talk
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