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About jetboy

  • Rank
    Well-known member


  • Aircraft
    Zenair CH701
  • Location
    Omaha Flats Airfield
  • Country
    New Zealand
  1. A couple of considerations... I thought the Rotax props rotate the other way, if so then the engine mount could not be adapted because the whole engine at the rear mounting has to move across and at a different angle - not really a problem just a bit more $. On the + side with any geared engine you get to turn a bigger prop because it can run lower rpm and gain efficiency, this is a performance increase without going CS - which could yield additional increase. The 2 jab in NZ I think are running as microlight class and doing well.
  2. its actually 6 lb-ft since they changed the attatchment to include 48 belleville washers https://jabiru.net.au/wp-content/uploads/2018/05/JPM3L01-4.pdf
  3. wearing out of oil pressure senders on the jab has been going on for 2 decades - the fix is to shift the sender to the correct location i.e. after the external oil cooler and the oil filter. yes the pressure reading will be lower but it is the gallery pressure not the pressure spikes straight out of the pump and before the restrictions of the external cooler and hoses that is the more important reading. I fitted a switch to the original port wired to the idiot light for backup indication, when the original sender packed it in - pic attached.
  4. Regarding engine stiffness after running, which I still have a measureable amount of, for earlier engines this was caused by design of the cylinder base flange and is corrwected by AVDAL SR050 attached below. My 2200 was built 2003, has the slotted piston crown and seems to stick the rings in the portion of their lands at midspan of the open slot areas below. A common cause of compression loss and valve damage can be head overheat leading to valveseats loosening and falling out then of course the valve gets jammed or hammered back Synopsis of an Engine Failure.pdf
  5. You'd use a more powerful battery than Rotax specify for the aircraft loads rather than the engine, so its not overkill. If stuck in the boondocks and leaving the master on you will probably appreciate the bigger battery anyway. I've used a Genesis 925 (commercial grade version of Odyssey, same specs there is also a Fullriver line the major difference is yellow black or red casing) There is someting odd about the PC680 specs where the PC625 are better despite being smaller, presumably cheaper. These are good products but really the same chemistry as the SSB an
  6. I've installed / fixed Becker, Xcom, Microair but only seen one Flightline 760 which the owner said was really good. Should be OK for most RA installs https://www.aircraftspruce.com/categories/avionics_instruments/av/menus/av/comm_0browse.html
  7. Rotax stopped the caged little end bearings about 30 yrs ago. I was flying my new-to-me 503 machine and with 5.5 hrs experience needles went thru the muffler etc.When I ordered parts the replacements had all needles no cage. But I replaced the engine with a new one anyway. Later on replaced the bearings and piston and flew this for 30+ hrs before selling. It went on for a few 100 hrs only lost a coil - then the owner put in a 582. That was all way back when there was no 300hr throwaway life and the most popular competition was another snowmobile motor - Cyuna. Probably the 582 had c
  8. Can you set the Xcom GAIN level to a lower setting? Mic gain is adjustable as a menu setting in the Xcom, If I recall it was a trim adjustment in rear of Microair. You want this set in flight noise conditions, so the modulation when speaking forcibly just gets to 100%. I've made this adjustment heaps of times, changing from readability 3 to 5.
  9. they were damn good when they came out but nowdays the ANR kits can be fitted to most regular headsets I use Peltor ear muffs as housing for the mic and phones out of other headsets as my spare units as I neveter liked the DC and their clones and the ear pads allways need replacing for about the same price as the whole peltor (3m) housing
  10. I cant add any crtique for the 4 CS props you have narrowed choice to, for my VP project the powerplant was set up for Airmaster but I wouldnt need a full CS system just inflight pitch change and with 90 SHP to run I think the lower power version of IVOprop would do fine https://ivoprop.com/ They have been around for ages and despite them looking like the blades are about to peel off the 2 attach bolts at any moment i've seen no trouble with them. Probably not as efficient as the other types because of the flat taper, the cost and weight is low.
  11. In GA aircraft, generally the alternator is swiched off especially in Cessnas there is an interlocked dual switch with the master. Normally the alternator comes on with the master but in case of runaway regulators, overvoltage etc. it can be isolated. My older Cessna had a generator controlled by the master pull switch so if you shut down the electrics in flight the generator field would also be disconnected. Depending on airframe, microlights that have a PMA and associated rectifier-regulator often do not isolate any of these items from the battery. In many respects
  12. I tried to copy the Camit idea of having an oiler for shutdown time. camit made their engines with small tubes drilled into the intake port on the heads, I thought getting oil sucked into the vacuum air port on the carb might work. Castrol 2T oil was used and it did go in with the engine running - and in flight when turned on - but no smoke observed and after standing for a while the oil just ran back out the tubing. So the answer probably is, plain oil just wont get drawn all the way up the intake runners. it might work if some oil was added down the carb vent tube that comes from the airb
  13. There was one at Rangiora NZ in a Zenair 701 i think but it was removed for something else only did a few hours
  14. #410 Ok, finally got a few hours down the shed this long weekend. First, a pic of the carbies and air cleaners on. Bit confused about your post Jetboy - are you saying they'll vibrate themselves off? Yes Marty I have seen installations where the carb has fallen off, not once, not twice, but four times on the same engine and each time care was taken to fit the clamp correctly. Rotax have a few SBs out on this issue and supply a better clamp system now. Then finally one of the club planes was doing touch & gos and just sputtered to a halt mid runway and had to be pushed off the
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