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Paul davenport

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Everything posted by Paul davenport

  1. Paul davenport
    An old mature aero engineer once told me that dual mags were needed in early days because they were so unreliable that operating on one was quite common hence the reason for a spare ignition source. But all reasons given so far make sense
  2. Paul davenport
    I just make sure the surface is clean and free of dirt grease (Wurth brake cleaner) and apply under and over weights and to the vertical spinner surface. Weights have to be cut off to remove, a word of warning if it gets on anything it is a devil to get off your hands and don’t even try to get from clothing
  3. Paul davenport
    Point taken skip I did mention static balancing in my previous message but what in effect you are doing when you dynamically balance the prop is fine tuning a lot of other issues . Fitting the weights inside the spinner is far better than drilling holes (as I have seen) and having the risk of crack developing. And if the weight comes off?. That’s why I use sikaflex. I have seen props come back from overhaul balanced by the experts still requiring that fine tune . I suspect that it might be as much engine issues as props, but whose got the money and time to persu that one
  4. Paul davenport
    The Aces balancer works out weight required its self ,no calculations required. First spin it collects info and makes a suggested weight and placement angle , based on the second spin and weights placed on it it works out the effect given the distance from centre . (Hope that makes sense)
  5. Paul davenport
    Good point about carb balance Mark . i have a cheat sheet with check points tracking ,engine condition engine mounts weather on the day wind speed. Be aware that gusty weather will effect the balance. Light congitions sun reflecting off rotating prop can interfere with balancer optic eye .Some times a static balance will be required before you can dynamically balance it. On some aircraft engines the harmonic balance weight bushes when worn prevent balancing altogether. If you are chasing a balance there is usually another problem. Moving the prop position on the gearbox of Rotax engines will some times help . My target is 0.05 or less but usually under this figure most people cannot tell the difference, especially on the big GA engines. Have fun, it’s rewarding getting it right
  6. Paul davenport
    I have been balancing props for some years now, using an Aces balancer. I use stick on alloy wheel balance weights which are easy to reposition . For the final solution I use one of several methods . I prefer stick on weights which if you use the inside ledge inside the spinner can give you the best results allowing you to access 360 degrees ,allowing for greater accuracy. Small washers can be used under the spinner screw also different length screws allow for some weight, but this method is only really good for small amounts of imbalance. Washers under the prop mounting is only a last resort as it does not give you the fine tune of 360 degrees. Be aware if you balance without the spinner on fitting it will in some instances throw out the balance . Balancing is rewarding when you get it right but can be frustrating. On finishing the balancing job I use a product called Sikaflex as a bonding agent, this stuff sets as rubber and unless you cut it does not let the weight go. Paul
  7. Paul davenport
    Always adjust mixture to the HOTTEST cylinder and let the rest look after them selves. So in my case through good luck or great technical ability ( I. Would like to think the latter, but that’s debatable ) my mixtures are within 30 degrees of each other. I monitor all cylinders, one Jab driver with similar leaning systems has 200 plus hrs experience and recommends leaning above 4000 ft. In my experience cruising at altitude can produce EGTS of lower than 600 c.
  8. Paul davenport
    I have now flown for some hours with a mixture control on my 230. Because of an EGT problem at full power I have to run a larger main and needle jet, at altitude it runs too rich and far too cool EGT wise, but with the mixture adjusted and EGT set to 710 I use between 19 to 21 lph . You are correct in saying the Bing doesn’t manage mixture very well and my experience confirms that up to 4000 ft it’s does the job, above this however it just can’t cope
  9. Paul davenport
    What a great idea , can we keep it Jabiru owners and pilots of jab exclusive and save all the grief
  10. Paul davenport
    Love those temps, 6 or 4 what have you done to get them
  11. Paul davenport
    It’s nice to have a cooling margin up your sleeve. Bit like temp guage on a car every one feels ok with the guage reading in the middle. Yes I saw a Rotec head set up I too like the jab simplicity
  12. Paul davenport
    I went for a fly yesterday and temperatures were 138 and lower. I think for longevity on the 6 this is about right as in my opinion a lot of problems are caused by temperatures as hot as what the factory calls normal, but I am happy to be wrong. Rotax temperatures are significantly lower and they do not seem to have any valve issues, now before I start WW3 it’s just an observation and I love my Jab warts and all
  13. Paul davenport
    Thanks for your reply. Your motor is a real mixture isn’t it, as long as it works and is reliable what else matters. My mates 230 is a later model with more hours on it but the engine has been overhauled by jab and is standard with hollow push rods and as such has more fin area than mine which I have modified to hollow push rods. His CHTs are lower with only a few simple mods, whereas mine has been a work in progress. My temps are now very even and mainly around 138 or lower on all but the hottest days and I choose to stay ground bound on those
  14. Paul davenport
    I have a KTI. Is it possible to replace the batteries in them I hate throwing away serviceable things which have never been used
  15. Paul davenport
    At Narromine last year Jabiru had a new head in development as a replacement for the Gen 1,2,3 series motors, looked identical to the G4 motor heads but held on with bolts. This head is being test I suspect the reason that non owner operators were asked not to reply was to stop drift and, hear say advice. No one can stop you from commenting but your comments carry very little credence
  16. Paul davenport
    Is there a difference between the early 3300 hydraulic exterior lubed heads and the later hollow push rod heads and the roller cam heads. On inspection of a mates later hollow push rod motor his heads seem to have more finning around the inlet exhaust manifold area, and his CHT. temps seem quite reasonable without any of the mods suggested by jab
  17. Paul davenport
    Happy with my 230 now I have the mixture and cht problem sorted. A pilot up the valley has a 160 apart from servicing no problems and he has around 600 trouble free hrs all leak downs in the 70s plus
  18. Paul davenport
    Please with all due respect to every one, Merlin, P&W , Rotax and any other engine EXCEPT Jabiru have no valid issue here. The original question was ONLY about Gen 4 Jabiru engines, I say again if you have knowledge about the original question please let us have the advantage of your experience, all other conversation is simply not relevant and Only those who have done the installation have the experience to reply The question has nothing to do with how good or bad any other make of engine is
  19. Paul davenport
    When people ask specific questions on subjects there tends to be a drift away from the subject by well meaning and experienced members who are very knowledgeable but who do not have actually experience in the question asked, and then it turns into a them and us discussion (in this case Rotax v Jabiru) . I would respectfully suggest that when asked a question on ANY forum subject that if you have first hand experience please give us the advantage of that experience, if not don’t enter the discussion
  20. Paul davenport
    I fly from a private strip around Wangaratta and regularly visit Bright, what would you like to know? . It’s a great little strip, I am sorry your experience was less than favourable. Mt Beauty is also a great place to visit with the added advantage of only a short walk to the town for lunch or accomodation
  21. Paul davenport
    Done but other files still occupy 9 Gig, which is twice more than all other files combined. I did google it and found out that resetting after a backup and then reinstalling is the answer
  22. Paul davenport
    From my limited knowledge the maps and in particular Oz Runways is not the problem . Apple seems to collect files and store them and that seems to be the fault. I need some one under the age of 30 to back up files and apps reset the iPad and reinstall so that the Other files disappear
  23. Paul davenport
    I have been battling with my iPad to reduce the size of OTHER on its memory, it occupies 9 gig of my 16 gig memory any one else have this problem and if so what was the solution
  24. Paul davenport
    I just mounted my plates with silicone , it allows for flexing without cracking and the silicone rubs off when you want to remove it ,use as much or as little as you want. To date they have not ever come off . The inner cylinder baffles just drop in allowing for easy removal and refitting of plenums . Also for those ac fitted with heaters look at blocking off the heater air inlet in the summer as it dumps air in the low pressure area of the cowling, I made a simple nylon plug fitted with an O ring and inserted it into the hole in the cowling . I have also blocked off the two holes allowing air to bleed into crank case past the barrels at the front of plenum chambers. Like I said still the same axe
  25. Paul davenport
    I have just looked at my knife sharpener with a high speed steel blade looks like it might do the trick
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