IBob

Hi Tozza, just did your survey. I note there us no option for New Zealand (so I identified as Australia). There are a few Kiwis here, you may want to look into that? All the best with your survey. Bob

But....apologies to F10 for the thread drift............(

OK, I was born there.....we're fine people....just misunderstood.........) I can also tell you a difference between visiting Glasgow and Edinburgh people: The Glaswegians will say 'you'll have some tea', while the Edinburgh folk will say 'you'll have had your tea'.........)

More likely Yorkshire, OK: Definition of a Yorkshireman : a Scotsman with all the generosity squeezed out................)

So. I'm not familiar with the internals of those engines: was the problem that someone did some disassembly and someone else did the assembly and missed something that had been disassembled?

I saw a Trimotor at Strathallen in Scotland in the late '70s. We couldn't believe how slow the approach was, it seemed to take forever to come over the fence. Someone had found it in Spain, and it was on it's way to a collector in the Sates, flying 'over the top' which was probably the safest route. We tried to get a jump from the thing, but the ferry crew were understandably not interested. We later heard that it had struck head winds on the next leg and turned back, having burned a significant portion of available fuel without actually clearing the coast. No news after that, so no doubt they made it....eventually.

Some nice low level footage.........followed by diligent effort to destroy the evidence.......... Note also second kea: these wee bastids often work in pairs or groups, with one or more providing a diversion while the crime unfolds behind you........

Just removed old Becker (German) Xponder. Screws for that are 3mm.

Marty, FWIW they are Bing 32mm carbs, though I'm not sure that is much help, as I have been unable to find the details you are looking for online.

Hi Marty, I believe what you are looking at in the Heavy Maint Manual is what you get if Rotax provide all the engine fuel pipework, including the splitter/manifold that ports to the 2 carbs, fuel gauge and return line. For my build, the splitter/manifold was supplied by ICP, and the engine came (new) without the pipework to the carbs. The carbs came with the banjo fittings, with barbs, to which I then attached the flexible fuel lines supplied by ICP. Sorry, I don't know what the thread size is. I guess an advantage of the banjo is that it keeps the flexible fuel line close and compact to the carb/engine without any tight bend.

Very envious of your hedgehopping, Brian. Here in New Zealand, I'm pretty sure you'd get birdstrikes. But, sadly, it's academic as we have a min. height of 500'AGL except in a very few specific training or competition situations (and even then we don't get to be right down on the deck).

Great looking machine, Brian. And I love the sound of the sort of flying you're doing!

Hi Brian and welcome. The S-12 always looked like so much fun to me! You mention your 912 has not had any SUs done. A while ago a member here had his 912 quit when both ignition systems failed simultaneously. By a great stroke of good luck, this happened on the strip, prior to takeoff. The problem was due to poor/faulty insulation in the wire bundle that comes from the alternator end of the engine, which also includes the excitation and trigger coils for the two ignition systems, and was supposed to have been fixed by SB 912-026. I though you may want to look at this. Here is his summary of the problem:

Before settling on 66", strongly suggest you look at prop comparisons on JG's website: https://www.stolspeed.com/

Luca, nice looking seat covers! Are these to go on the adjustable seats: if so, they appear to have a very high back compared to the original adjustable seats. Have ICP modified the seats also?

Non-aviation thread-drift anecdote: Back when I did industrial automation work, it was usual to install pressure transducers in the base of large tanks as a means of logging tank levels. One freezing works I serviced had repurposed a couple of 10metre tall tanks for warm water, and I was called in to a failed level fault, determined that the transducer had failed. The duty sparky swapped the transducer, came and told me there had also been water in the transducer connector plug, which was unusual as the connector has it's own gasket and cable gland, and is normally watertight. Meanwhile, the new transducer was blowing fuses, and when we opened the connector, we again found water. So the sparky stripped the insulation looking for dry wire. Then he stripped some more. And when he had stripped back 15metres along the run and we were still finding water, we gave up and put in a new wire run. What had happened was that the diaphragm in the original transducer had failed, allowing water through the body of the transducer and into the connector block. And from there it was pushing it's way steadily up our signal wire, due to the 10m head of water in the tanks. Had we left it, it would eventually have made it's way all the way to the PLC cabinet that controls the water systems: yet another very good reason why we never, ever, used top entry for wiring in automation cabinets.......

Nice work, Marty...and I love the helmet! Dzus: I swapped out the aluminium copies supplied, which bind, for steel ones that don't but I guess you'll be working with steel right off. On my cowls, the wire bit is riveted straight to the back of the lower cowl fibreglass, no doubler, countersink pop rivets BUT I found it necessary to 'adjust' many of them, which were either too tight or too loose. This would be due to variations in FG thickness. I made the adjustments one Dzus at a time, by drilling out the rivets, then either adjusting the shape of the wire a bit, reforming it to make it a bit deeper or more shallow or in a couple of cases I used packers cut from thin aluminium strap (2.5mm?), with longer rivets, to pack the wire bit away from the rear face. It wasn't difficult and I now get a snug cowl fastening that is easy to remove and reattach, no drama. PS the hugely experienced pilot who test flew SVA for me walked to the front, grabbed the cowl by the air holes and tried to wiggle it up and down. I now do the same, after checking the prop, as part of my pre-start.

I burp the Rotax and check oil level every preflight, Marty, I'm sure most do the same. A hatch makes that quick and easy. The fastener on mine is Camloc, as supplied with the kit.

The work is in the cutting/fabrication and fitting of the hatch. The hinge is simple to fit and neat in action. So, why not?

Not picky at all: Some months ago I met someone who was waiting for a replacement set of wings for their Jab. They had been unwittingly using fuel with ethanol, causing the wings to start delaminating.

Digging down to what fails: My understanding (and i'm happy to be corrected) is that with soldered joints or terminations of multi-strand wire, the strands are welded together by the solder for short distance and so unable to flex. Which concentrates any flex at the point where the solder ends, and the strands are free to move. This then becomes the potential weak point. However: In the case of the D-sub connector, the wires are held by an internal clamp before leaving the connector. And if this clamping is done correctly, with a small amount of slack in the individual wires, there should be no flexing at this potential weak point. Stripping, soldering and final assembly would still need to be carried out carefully.

Thanks for putting it out there for us to pick over, Alan. It's had me thinking through what I might do in similar pre-takeoff circumstances.

KGWilson, all good. And yes, the siting of the Rotax fuel pumps is less than ideal. I think there is sometimes a misunderstanding regarding the Zenith/Savannah return fuel line: I come across references to it as 'returning excess fuel' or 'limiting excess pressure' but the orifice is so small (0.4 or 0.5mm, see pic) it will do neither of those things. I believe the purpose of it is to reduce the likelihood of vapour lock, as described. As to where or not it is 'necessary', for the cost of a couple more fittings and a run of pipe I would think it an excellent innovation. (PS my prestart routine includes: *Turn on aux fuel pump, observe pressure rise to > 2 PSI. *Turn off aux fuel pump, observe pressure fall to 0PSI to ensure fuel return orifice is not blocked.)

Okay, vapour lock. To consider that more closely (in the context of a non fuel injected engine) : Some of the pipework is full of vapour instead of liquid. And if this includes the main fuel pump, then the pump can get only limited traction, so we are now relying on gravity feed to push the vapour out via the carburettor float needle jets. Furthermore, if part of the pipe work is still hot, the arrival of liquid fuel may result in more vapour. In the case of the Savannah, the electric fuel pump is low on the LH firewall, receiving fuel from a line under belly of the aircraft. Some builders now prefer to site it behind or under the seats. Either way, it is well placed to receive and pump unheated fuel. Meanwhile, at (or just before) the carburettor end of the setup, the return fuel line mentioned above allows vapour to bleed out of the system and back to the tanks. This seems to me to be a pretty good system, in terms of reducing the likely impact of vapour lock situations.