Bruce Tuncks

I agree with Marty Space. In my time, I have seen guys who were told to go away do big things. One was eventually the tugmaster at Gawler for many years. He was a great guy and a good pilot and instructor but superficially he presented as a bit of a spastic. Anybody who was smart themselves could see past that but alas there are many stupid people out there, some in positions of power. Keep trying till you find a good school.

Speedbrakes on gliders are wonderful things the Jab doesn't have. You can get away with anything on a glider, I have seen guys rocking in their seats to stay in the air for the last k or so, with no energy left. OR you can come over the fence at 1500 ft and still only use 300m of runway . ( no kidding.... one overcast day some of the slightly bored guys decided to do an unauthorized competition, of who could be highest over the fence and still stop at the piecart.) The Jabiru is a lot harder to land, you need to have the speed and altitude sort of correct for most of the circuit. So, rf guy, your postings are quite correct . Actually the Jabiru is harder to land than a Pawnee or a Chipmunk, both of which have better shock absorbing u/c's.

Thanks f10. You didn't do too much wrong in my opinion. Glider pre-solo checks used to contain a circuit with the ASI covered up. . All that happens is that the student has about 5 knots more speed than usual, and this is just fine. But all the same, I will be more careful on my checks after your story.

Is that where the foxbats come from? The Ukraine?

The Jabiru sender is interesting in that it is screwed directly onto the engine block against the sender instructions. So it fails from vibrations, but it does not have the possibility of losing all the oil from a leaking hose. I have known of 2 failures . In each case, there was no other corroborating evidence, especially the oil temperature and the cht's , to indicate a problem. In each case, the issue was fixed with a new sender. I have no doubt that if the sender were separated from the block with a bit of rubber hose, the senders would last longer.

I like Yenn's idea, it obviously has fewer pulses.

I ran the tacho directly from the alternator ( there must have been a dropping resistor in the wire) and it worked so good that we tried it on a club plane. Alas, the indicator stopped working at 3000 rpm. Maybe a diode in the circuit would have helped. I thought at the time the pulses from the alternator were too close together but on my display it worked ok.

They approached us... I think it was about 500 dollars for us with them paying for all the fees too. The guy said to me..."I often get asked when that MPA plane is coming..." So he looked up the directory to find just where VH- MPA was. Naturally, we didn't care just what the letters on the plane were. It was like a pawnee but uglier and it had a wooden mainspar with aluminium ribs.When new, it was the cheapest plane out there.

We ( the Adelaide soaring club ) made money from selling the rights to the "MPA" letters on a Callair to the Maningreda Progress Association which I think is in Arnhem land. I thought at the time they had too much money, well lots more than our club had anyway. The Callair should have won a prize for the ugliest looking tow plane ever.

Good question phlegm, I hope the answer is acceptable to you.

My son is over 6 ft and he says the SK Jab is too small but the 230 is ok. The german gliders used to have a legal limit of 110kg seat weight, so this was your weight plus clothes plus chute. I think this has been increased lately. I dunno what they consider airline passengers to weigh, but they don't make them stand on scales like they used to. I think the fat lady bleeding hearts have sabotaged the whole idea.

It was a datsun 180 and yes it may have once been near the sea. Inside the box sections, under the doors, the rust was terrible and it was mixed up with the inhibitor spray. I was shown this car after saying how the inhibitor spray would fix the problem. It sure did not.

Spraying stuff inside the tubes is intuitively correct. After seeing a car which rusted worse after this sort of spray, my advice would be to keep checking the rust. I have no explanation as to what was the chemistry with that car.

Good stuff here guys. I especially like how doom and gloom ( 178 seconds to live stuff ) has been balanced with real experience. Bohli compasses were banned by the GFA for competition gliding because people had learned to use them to cloud fly. There is actually more cloud flying among gliders than is admitted to. On a good day, the cu's are concave and the best lift may be at cloudbase. It has been known that working this lift, then straightening out on track, involves flying through some cloud. Very safe if done carefully. Personally, I didn't do this but sped up to stay under the cloud... and I never won a nationals. Here's the deal... clouds are not all the same! I seriously recommend deliberately flying into some safe little ones at a safe height and speed. The only danger ( apart from getting caught ) is overspeed of the aircraft. But a smallish cu does not extend vertically enough for an initially sensible-speed plane to get to wings rip-off speed, even if you lose it and do a spiral dive.

here's my yachting Garmin. I think is was well under a hundred dollars, and it just shows the direction to your waypoint. I reckon it works well as a backup to ozrunways. My son bought me ozrunways after finding the old map I had been using.

The difference between upper and lower cowl pressures is what matters. This is in the Jabiru manual. But help, I've tried to understand how a radiator can actually increase the total thrust, but I can't. The idea that the higher temperature of the exhaust air from the radiator leads to less density and therefore higher velocity is something I could regurgitate for an exam but can't actually believe.

You missed the point turbs... it has been many years since a DC4 flew out of Adelaide, but they kept the same lines on the map. This means that you can still inadvertently enter "controlled" airspace near Burra, even though the need for that to be controlled airspace has long gone. This happened to a good mate of mine, he had a please explain to answer because he had a transponder on. As a matter of fact though, I sure would stay well away from a DC4 with one engine gone. Apparently, it was not that unusual to have this happen. I read that the Super Constellations frequently lost one engine on their long flights. Also, I do appreciate the possibility of training flights there, not that I ever saw anything like that in 40 years.

My experience is that the powers that be will use the information gained against us. The only people who have ever got into trouble with airspace at Gawler were those who had used a transponder. They had committed a "violation " of airspace which had not been used since the days of the DC4. Yep, those lines on the map were based on the climb performance of a DC4 with one engine out. Why did they not just use the information from the transponder to make sure there was no mid-air collision? We are especially bad for being submissive in Australia. Once I listened to the radio exchanges between a pommy pilot ( who was going to overfly the Grand Prix crowd in a jet) ) and an air traffic controller. The pommy pilot was saying that he didn't want the state of SA shut down airspace-wise. The Australian ATC guy was bewildered by this. Surely the more airspace he had then the safer he would be.. Well I don't think the whole state was offered to be shut down, but my airspace at Gawler was, even though the pommy guy was not going to come to within 50 km of where I was. In the event, the ATC guy listened to the pommy pilot and so I was able to stay flying. But I have a deep distrust of big government. And a fear that they will charge us " user pays" fees for services we don't want.

I like the idea of using the wing leading edge for cooling. There is laminar airflow here, but there is plenty of area too. I think this was used on some schneider trophy planes. Very difficult to do for an amateur constructor.

Jabirus provided Araldite 3600 with my kit 20 years ago. I think the glass was cheaper than the interglas but it was ok. Interglas has an oval cross-section to each strand and this makes it drape better apparently. Mark Morgan ( Waikerie ) sold me Scheufler L285 resin and hardener for my last big job years ago. It was good stuff, blue resin going greenish when mixed. Be very careful about the exact type as not all epoxy resins are compatible. There is a table published by the GFA, there would be more up to date stuff from RAAus I hope.

Fair point turbs, specifically I am talking about epoxy resin ( shell epikote MGS with L20/epikure MGS ) or any epoxy systems approved by the LBA. Glass would be Interglas 210 gm/m2 for example. Now that I have been specific, perhaps you could be too. Please no vague references to boats for example.

I reckon this topic is worth its own thread so here goes... It is asserted again that fiberglass does not fatigue. There is a type of overload failure where the resin powders and eventually falls out leaving a "greenstick " failure. There is another type where the crack can avoid glass fibers and the fitting suffers delamination failure. Apparently this has actually happened on Jabiru u/c legs, where the leg gets soft as a result and ground handling becomes difficult. But this is not an example of fiberglass fatigue, it is an example of poor design and /or construction. I would really like to hear of an example of a properly-designed and constructed fiberglass part which has failed in fatigue. After all, the glass fibers are crack-stoppers, and if there are sufficient of these in the crack pathway then the crack has to stop and fatigue is halted in its tracks. The glass fibers themselves do not propagate cracks. I would like the example to include numbers and other design details. Personally, I doubt that there are any real examples, but I have respect for turbs and onetrack and their knowledge . Here's my understanding of "fatigue" and gliders... When Blaniks ( metal) gliders arrived, they looked great and nobody had ever thought about fatigue. The wooden gliders we flew had unlimited life. Then there was an example of a Blanik in Europe falling to bits in the sky. When the dust settled, Blaniks were given a 3000 hour life. ( This was later extended by the heroic efforts of Daffyd LLewellyn ) Well the Blanik importer got angry, and he discovered that FRP ( fiberglass reinforced plastic) gliders ( all the rest in those days ) did not have a special exemption, and he prevailed on CASA to enforce this ridiculous limitation. There never has been an example of a FRP glider failing in fatigue. The german manufacturers responded by submitting paperwork and eventually the "life" of a glider can be up to 18,000 hours. Unfortunately, Grobs went out of the glider business and so Grob gliders are limited to 12,000 hours. Several airworthy gliders were scrapped by this nonsense. At the Adelaide Soaring Club, we investigated paying for engineering paperwork to extend this life, but really the membership wanted new stuff anyway, so we practically gave away 2 pretty good gliders. About this time, a great engineer ( Patching ) got the RMIT to put a Janus wing onto a steel loading machine. I think GFA helped with the funding. Not unexpectedly, there was no fatigue discovered at all. Well the machine fatigued, but the Janus wing did not. When I saw the machine in action, it was bending the wing alarmingly, with the tip almost at 90 degrees to the root. In 3000 hours gliding , I never saw such a load applied in the air. On enquiring, I was told that the project was running out of time and money and people were getting impatient with no results. Then they measured the wing thickness, and found it to be a few mm over so they increased the loadings . They also did some deliberately substandard "repairs". Eventually, some of the metal fittings surroundings started to show signs of greenstick failure. Then the project was concluded. It was the only proper scientific fatigue test done on a real wing that I have ever heard of, and it proved to me that the whole FRP fatigue business was full of bureaucratic fraud.

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" fairings at the duct entrance on the upper cowl to deflect air in but these did exactly nothing. They were just taped on, so their removal was easy. The standard thing to do on a Jabiru is to put a skirt on the lower cowl exit, and this works but it must increase the drag. I did a very small skirt and it sure helped.

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 with the inlet side of the carby, trying to even out the egt's, before I was told on this site that the real action needed to be on the downstream side.

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.