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Bruce Tuncks

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About Bruce Tuncks

  • Rank
    Well-known member
  • Birthday 08/08/1945


  • Aircraft
    jabiru sk
  • Location
    Gawler, South Australia
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  1. I liked the stuff I saw using tufts because it showed the airflow to not even be in the expected direction, but in the end, my tool was just a water U tube. the ends of the tubes were in the ducts or the lower cowl, and the U part was in the cockpit. It was these readings which finally explained why the RHS ran cooler than the LHS, and I got rid of some of the difference by connecting the 2 ducts with a bit of vacuum-cleaner hose. Yes the difference was counter-intuitive. After figuring that the prop was going upwards past the LHS ( as seen sitting in the cockpit ) I tried "eyebrow"
  2. My experience with the SK jabiru was that the cooling ducts were not good enough to begin with but after hours of tweaking, they were much better. I still, to this day, watch the temps on climbout and do the things skippy says if needed on a hot day. Keeping the CHT's under 160 C is the aim. I fully agree with the idea of experimentation. That is, proper experimentation backed up by proper measurements. Tufting and photos qualify here, not that I have ever done this but others have and their work was very helpful. And getting other opinions sure helps too, I spent a lot of time playing w
  3. Yep, I am now flying a J230. I like it and it is easier to land than the SK was. I would still like to try an audio flare aid. Here's a coincidence.... in the latest "sport pilot" mag there is a story about lidars ( laser range finders) being used for flare assist tools. I really would like to hear from somebody who has used one in practice. Nev, how did they know when to flare those big airliners? I reckon you were so high in the cockpit that judging when the wheels were a couple of feet off the ground would have been real hard.
  4. I just looked up "car parking aids" and they have ultrasonic stuff too. Surely somebody has tried one for flaring out?
  5. I looked up the Sea Rey website where they have an ultrasonic thing which has the audio signal Spacey suggests and I agree with. The rationale is that the water is sometimes too glassy to see it properly. I would like to try one just to make my landings easier. Yes, I appreciate the comments made about learning properly, but it is still the hardest thing in flying I reckon. And I don't fly a seaplane, just the Jabiru.
  6. Thanks RF guy. I grappled with the question of glider ventilation air for years before coming to the view that there was no zero-drag solution. you take in air at the relative airspeed ( 80 knots say ) and then let it out at zero knots relative to the glider. So each kg of ventilation air costs 840 J. This can only come from the potential energy of the glider so it costs a 300 kg glider 0.3 meters of height. Airliners knew about this and so they recirculate the stale main cabin air all day. Only the pilots get fresh air. Mind you, with the gliders, there are worse ways to get
  7. The detail design of the airflow from the opening to the radiator is very important. You need to avoid separations and steps and leakages. Thats a very good question pen-name. I don't see how a bigger radiator could be less drag, but there may be a way. I don't think Rotax engines are completely liquid cooled , It is only the heads. A coolant leak when at a remote location can be very expensive. Often times, you are not allowed to fix it yourself, so you are up for charter flying a lame in n out.
  8. I thought that the legal reserve was 40 mins flying time, which is 11 liters for a 2.2 Jabiru. I just don't know under what circumstances it is legal to use some of this... maybe none ! Personally, I have never used any reserve so I need some help here.
  9. It would have been OK if he had done the check earlier. As it was, he did it just as he was lining up for take-off.
  10. There was a Jabiru in SA which "landed" in a vineyard. Apparently the student pilot turned off the fuel when doing his pre take-off checks. There was just enough fuel in the bowl to get airborne and past the runway. I'm pretty sure they were uninjured because the instructor took over and they came down between rows.
  11. Apparently it really happened that a Stralian Quantas captain said "welcome everybody here today" A group of Pakistanis got really upset at this and they sent a spokesman up to tell the captain.. " we did not come here to die, we came here to fly to London"
  12. I think it was Old K, but somebody tufted a plenum and found that the air flow directions were sometimes not as our intuition would expect. For example, airflow near the crankcase center was forward ! So I learned from this that you needed to test out theories first, and tufting and photographing was a good idea. Once, this was done on a glider wing and it was found that the flow on a glider aileron was ALONG the wing towards the fuse on the top surface. A separation lay ahead of this flow.
  13. We used to have quite a few foreign students, some of them wore coke-bottle glasses and spoke poor English. I reckoned that they were the sons of Indonesian generals and they were going to become airline pilots. Hopefully back in Indonesia. Back to radio transmissions... I rarely hear the place of origin mentioned even on unicom 126.7, where it could be lots of places. You can only tell they are a long way away because of the poor signal strength but it would be good to know for sure that they were at Naracoorte for example. Yes, at the beginning and end of each transmission is correct.
  14. I have both, and I much prefer the android galaxy because it is easier to use. My smart son says that the Apple has more features, and I am sure he is right. But I want less features and easier to use. Here's the explanation... every feature requires a command. So you pick up the thing and if you have your fingers touch something, you get some feature you didn't want.
  15. I've never heard of an aircraft failure due to debonding, although I have heard ( but not seen ) a Jabiru undercarriage leg which went "soft" due to disbonding within the leg. This leg did not fail, but was nasty to handle on the ground. Anyway, a question for you boat experts... Are those black sails on some leading ocean racers made of carbon? Since when did carbon fiber become used for sails? are they much lighter? what about their porosity? Could ( should ) I consider carbon u/c legs for a Jabiru?
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