Keenaviator

Has anyone seen a 912 hydraulic lifter? If so is it as big/heavy as those used in Jabs? Laurie

Ross, I was just defusing - not interested in getting into an online blue with someone I've never met. Laurie

Fair enough.

Innocent until proven guilty Did you notice that dates on this website? The incident/accident happened in 2001 and it looks like the the website was updated in 2011. Laurie

That depends on your line of business. Laurie

I believe that over the years, leading up to the hydraulic lifter version, Jabiru did a pretty amazing job of developing their own engine with basically just a few cluey blokes working together to produce a lightweight four stroke direct drive aero engine. Without the backing of a multi squillion multinational company. A big pat on the back for the Aussie spirit of having a crack! The development included (amongst other things): flywheel screw failures - increase screw size from 1/4" to 5/16", dowells, 'spider' exhaust valve failures - redesign exhaust manifold to do away with gaskets cooling - ongoing induction distribution - several evolutions of manifolds hydraulic lifter development - change cam profile several times, fast bleed lifters, now roller followers through bolt failures (which appeared after hydraulic lifters introduced) Does anyone actually know of a pre hydraulic lifter Jabiru engine suffering through bolt failure? I know the Rotax 912 series of engines use hydraulic lifters. Can anyone tell me what a Rotax hydraulic lifter weighs? The reason I ask is that the hydraulic lifters used by Jabiru are a big, heavy lump of metal, something like 130 grams each (normally used in a Chevy V8). The original 'solid' lifters are very light, about 30 grams each. Lifters are situated between the camshaft lobe, the push rod and rocker arm which is under spring compression load by the valve spring. As the engine operates the camshaft rotates, the lobe pushes the lifter which pushes the push rod which pushes the rocker arm against the valve spring. This all has to do this in unisen in addition to hydraulic lifters having to maintain correct clearances. When this is happening at operating speeds those heavy lumps of metal are expected to go backwards and forwards (stop and change direction) very quickly and the forces involved must be much higher than with the lightweight 'solid' lifters. A person with a better physics background than me would be able to calculate this in a flash using what I would think are common formulae. It is my opinion that Jabiru are barking up the wrong tree persisting with trying to get the heavy hydaulic lifters to work (including now using roller followers to cope with the loads on the camshaft). Ian Bent is on the right track with retaining lightweight solid lifters (along with his other developments). Why are Rotax are having a good run with hydraulic lifters (which operate at nearly double the speed). Are the ones they use much lighter than Jabiru's? Laurie

Mike, have you done the 'dowel' mod on the flywheel attachment? I believe there is a drilling jig. Also if I were to do this I would fit the steel 'spider'. I have 620 and primer, a couple of weeks rec leave and a desire to visit some folks in SA. Laurie

It's a fine thread OME. I recently installed a new (larger) prop flange for my new Jab Scimitar prop. I followed old directions using primer and 620 on a cool day. Did the tension in three steps, very quickly and all seems to be good. If I were to do it again, I would be using the new procedure in that the screws are torqued straight up to 30'lb in one go. Laurie

Do we have statistics for fatal crashes resulting from engine failures Jabiru vs Rotax?

Yesterday I ended up about a mile south east of that strip. I'd left my car at the old pub site and didn't quite make it. I've heard that the owner of that paddock strip is not local and is not keen on anyone using it. As an aside, I did end up landing there several years ago in a C172 when the 'slide' closed in with very non VFR weather. The pub was still there then and we had a nice dinner there. As for me refering to your Auster as a clunker, that's probably a bit harsh. I just get a bit jack of derogatory remarks because you may not be flying the same type of aircraft, be it Jabiru powered, Rotax powered, Lycontinental powered, hang glider, sail plane, rotor craft etc........ Flying 'bedsheets' (jellies, tea bags.....) are pretty mininalist but you are absolutely flying 'by the seat of your pants'. The flight yesterday was 1 hour 43 minutes and I did not burn a single drop of fuel. Laurie

The track log doesn't appear to be consistent with witness reports of a low power go around either - just an over flight, orbit, mid down wind joining of the circuit, base and final.

Yes. We look for forecasts of light northerlies and clear skies. I'll make sure to keep an eye out for your old clunker! Laurie

Yesterday I flew my paraglider at Flowerdale from a 750' hill in very light wind and thermals. The first flight I got to 2400' then bombed out and landed. After relaunching I had to scratch around far ages, got as low as a couple of hundred feet but then found a slow climb that eventually took me to 4500'. I managed to get to Glenburn with subsequent climbs barely over 3000'. Laurie Ps I have some video of the flight that needs to be edited

Gliding operations so probably nice unstable conditions + a bit of wind, dust devils - you'd want to have your wits and reflexes finely tuned and maybe some good fortune thrown in. Laurie

Coordinate all the controls properly.....It takes time and practice, ie repetition

Is it known whether or not proper earthing practices where carried out where these refuelling fires have happened?

All the photos of the cracking in the heads appear to be fine finned. Any cracks as described detected in earlier thick finned heads? Laurie

To lose 3000' in 30" is 6000' per minute. That's a pretty radical rate of decent. This is not consistent with controlled flight. RIP fellow flyer. Laurie.

That 'lunch bag' looks a lot like a paraglider/hang glider reserve :) Laurie

That's brilliant Allan. Love to see it some time. Laurie

Galaxy 5 - half the price, can get to battery, can insert micro sd card, soon will have ozrunways. I running out of reasons to remain loyal to apple.....Laurie

Have you considered having a tube running from the cockpit to the tail skid so you can feed grass seeds into the furrow left behind, a seed drill? Laurie.

That's good to hear. I'm glad I did an hour or so with Gerard Lappin before going off solo in my Jabbie. Very little flying planes for a couple of years while building shows plus my long winged Jabbie is different to others I've flown. Getting the hang of it now after 34 hours. It's funny but it's a relatively easy plane to fly but not that easy to fly well. Looking forward to hearing how yours is going. Laurie

How's the test flying going Mike? Laurie

Just fitted my new Jabiru Scimitar prop (60 x 38). I had to slightly modify the spinner and backing plate to work with my cowls. All we need now is some decent weather for a test run. Laurie.