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Keenaviator

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Posts posted by Keenaviator

  1. Thanks Laurie,Good to see someone who understands and works to the basic principles. How 'bout some pics of the under cowl work? 15c ambient is fairly cool, sounds like southern highlands weather. It will be interesting to see what results you get on more extreme days. What's the vertical gauge mid panel? Do you plan to monitor all CHT's & EGT's?

    I'll put together some photos soon.... The outside temp at 2500' I guessed since it was 18 on the ground. I found today why it has been running so rich - I checked the main jet and found it was a 255, normally fitted to a 3300. That's why the fuel flow numbers have been more like those for a 3300, not a 2200. Anyway I was given a 235 main jet to try and it seems better. I'll get the 245 main and recommended needle and needle jet for this motor asap because I wouldn't be surprised if it is fitted with those for a 3300 as well. The CHT and oil temperatures remained the same with the smaller main jet. The engine is now due for its first head tension and tappet check. Think I'll now hold off on further flying until I can get my hands on the proper needle and jets. Regarding full monitoring, I'd really like to but probably at bit hard to get past the finance minister and the moment. For now I'll stick with monitoring the theoretical hottest and leanest cylinders and checking the colour of spark plugs. Regards, Laurie

     

     

  2. I worked on ensuring a good pressure differential between the top and bottom of the motor. I shifted the oil cooler off the sump and fitted a larger Serck cooler with AN6 fittings (fitted larger fittings to the oil cooler adapter to improve flow) at the rear of the engine on the airframe instead of the engine so it is not subjected to as much vibration. This oil cooler has a naca duct with a 2" scat hose leading to it (air flow controlled by a butterfly valve that can be adjusted by the pilot). Next I reduced the size of the old oil cooler air inlet beneath the spinner (bottom of cylinders) by about 80% and fitted a close fitting duct to the sump to direct some air through the cooling fins cast into it. - this meets neatly with the air inlet below the spinner. I closed up the holes in the Jabiru cylinder cooling ducts (couldn't see much point in giving air another option other than through the cooling fins) that allow a small amount of air to bleed into the area between the top cowl and inner of part of the cylinders and crank case. I'm very happy with the results. Flying today in cool conditions around 15C at 2500' CHT was around 90C and oil temp 80C with the air shut off from the oil cooler. I opened the air valve and a short time later I saw the oil temp coming down further; closed it and it settled at 80C. Laurie.

     

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    • Informative 1
  3. Very pleased with the way this machine has turned out. It flies straight and engine temps and pressures excellent - the under cowl mods work a treat. It's running a bit rich (exhaust pretty dark and a slight miss at WOT above 2500' that gets worse with carby heat as expected - will investigate jetting/needle position). It glides very nicely too with those long wings. Sink rate at MTOW about 400 fpm (engine off with CFI for company). Cheers, Laurie

     

     

  4. Dafydd said " you cannot bore out a Nikasil barrel to the next oversize, as you can with a plain steel barrel" .................... Mainly True................. But this statement is dodgy on two counts....one being that nobody bores out Nikasil barrels anyway, and why should they? It's simple enough to de-electroplate the barrel, repair any damage in the alloy and replate. I have had it done. The second is "as you can with a plain steel barrel" Good luck with boring a Jabiru barrel 20thou oversize. If they break at full size, they may break quicker with a thinner wall?.....By all means try to replace the steel barrel with an alternative, please.....

    Do Jabiru cylinders break? Laurie

     

     

  5. I noticed while building my Jabiru UL450 that the wings were absolutely straight - no washout. The rigging of the flaps appears to be how Jabiru get the centre section of the wing to stall before the tips. The flaps are rigged a couple of degrees down while the ailerons are set at zero degrees. They are also quite specific in the rigging of the elevator, 18 degrees up and 6 down (limiting power to achieve very high angles of attack?). Do you have any experience with these Dafydd? Laurie

     

     

  6. A bit of thread drift, but I liked flying the Piper Archer and Savage Cub because they both have manual flaps. Both use a lever like a hand break (for those who don't know), heaps better than electric IMO. It makes it easier and a lot quicker to remove the flap on the ground to get weight on wheels.

    Collective! My Cessna 150A tail dragger had this and it was very handy. Laurie

     

     

  7. I've heard of the inside of the fuel line being shaved when installing onto a spigot on one of the many fittings. Sounds like you fuel flow is being restricted somewhere. Also ensure there are no kinks in the lines. Laurie

     

     

  8. Fantastic Bob! Well done. When is the first flight?

    Yep, well done Bob. I reckon I have some idea of how you are feeling at the moment too as I'm waiting for my registration to come from RAAus.....

    Cheers, Laurie

     

    P.S. I've just started some leave so real keen now to get the little rectangular bit of plastic (reg card) and get on with it. 25 hours within a 40nm radius of YLTV.IMG_2376.JPG.f89a480811ba16696e781211ac46ad5a.JPG

     

     

  9. Rather a sweeping statement and a bit of an insult! I'm not sure if CASA is there with a budget to fill.I can understand the angst if you are rushing to the loo after a long flight.

    I am driving so I will be at the mercy of NSW's finest for about 10 hours. A ramp check as opposed to a speed check would be a pleasure.

    Are you sure? Who says you have to speed? Give me as many speed checks as you like. There are too many variables with a ramp check including the experience of the enforcers.

     

     

    • Haha 1
  10. Geoffreywh - In answer to your question I'm not afraid of them, it's just the fact that they feel they need to be there. It seems to me they've been far too heavy handed where RAA is concerned. Slowly but surely they are imposing themselves more and more on us as GA numbers dwindle. Got to have someone to bully.

    We're a soft target. Laurie

     

     

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