IBob

OME at the start of my build I asked about the Black Stuff, which turned into a thread here, and which, like so many conversations about painting aircraft, devolved into various strongly held views with a fair bit of heat. In the end I came away. And I spray primed everything instead of using the Black Stuff. However, like Mark, if I were doing it all again, I would use the Black Stuff: I'm sure it would be a lot less work for the same or better result, provided one had the roller (discovered by Australian builders, I believe) for applying it. It's called the Black Stuff because it arrives from ICP in an unmarked can. But once upon a time the cans were marked, and somewhere back in that Black Stuff thread is what the cans used to say. As I recall, it's a water based etch primer.

It's all aluminium, apart from a few bits of steel in the upper cabin frame and cockpit end of the controls. I don't know what Zenith reccomend, but ICP supply a primer, to be painted on all mating surfaces. Curiously, some folk think this means on one mating surface only, but that's another story. Mark Kyle knows a great deal by now about the work involved in dismantling and rebuilding the Savannah, which evolved out of the 701. I'd be listening to him.

It's an all aluminium aircraft, OME: the coverings are the aircraft. And a major concern if it's been stored outside for a long period would be possible corrosion at every point where a piece of aluminium meets another piece of aluminium....(

Hm....no slats and VGs. Fit a Savannah stab/elevator to it (worth looking at the South African blog on doing that) and you'd just about have a Savannah VG!

Not for nothing is it called cattle class......(though not that I've travelled any other way).

I'm told a fair bit of this engine theft goes on in Europe, and on occasions they loot several engines in one session: apparently they don't bother undoing anything, they just take big bolt cutters to the engine mount..........

They certainly claim a pretty impressive spec. for that device, Skippy: and to be fair, it does sound as though it would do the job. I see it also incorporates filtering, which will be some digital or analog system for averaging readings over a period, providing a steady reading if the fuel is sloshing around. About all I can add is that we learnt to select transducers of an appropriate material for the liquid being measured. We generally overspecced them in terms of range for improved durability (eg if expecting to measure 0 to 10PSI, we would install a 0 to 20PSI transducer). We learnt to provide a warm dry environment where possible (the body of the instrument will 'breathe' with varying atmospheric pressure, and is likely to fail earlier if 'breathing' moisture or contaminants). And our experience was a significant initial failure rate (maybe 10%?) but with surviving units usually providing good long service (which would seem to indicate some critical potential flaw in manufacturing). This was in very large hot and cold water tanks and also in industrial refrigeration plants with 4 to 6 compressors, where each compressor would have 5 or 6 transducers, and the whole engineroom would then have a further 3 'master' transducers. I hope and expect the technology has moved on greatly since then: industrial transducers is a huge and constantly evolving industry

Hi again, Skippy. We used to use pressure sensors to gauge level in industrial hot and cold water systems, but these were big tanks, and even then the transducers (senders) had to be quite sensitive. In very round imperial numbers, 1 atmosphere pressure of petrol would be 40ft deep = 14.5 PSI So if your tank was, say, 32" tall, your pressure gauges would have to detect a range of 0 to 0.96PSI, from empty to full. This can certainly be done, but in practical terms those are quite fine pressure measurements, and keeping such a sender calibrated and free of temperature drift would be quite challenging.

Skippy, did you look at Appendix A, Fuel System Additional Information? It goes into the fuel system in detail, and sounds to be using a tank similar to what you describe. And it seems to me it gives a good view of the possible shortcomings of such a system, at least as configured in that particular aircraft, where they had quite different readings on the ground and in flight, plus confusion as to whether fuel figures included the reserve side quantity. Add to that the possibility of unporting on low fuel in a hard climb, and uncertainty around actual quantities due to the possibility of fuel sloshing from one side to the other in flight. I would add that I was surprised to see the fuel tank and level tube have separate vents to atmosphere. With that arrangement, even a very minor difference in airflow round the two vents will result in an incorrect level reading in flight.

Hi Skippy, I can't comment on senders and gauges. But I would say that a receiver or collector tank, as described by Blueadventures above, is a very simple and worthwhile fix for various known gotchas, including momentary unporting of main tanks, and exhausting available fuel for various reasons on takeoff or climbout. The one he is using is 6L capacity, and fitted with a level switch at the top, giving approx 20minutes of low fuel warning, which is 20 minutes to sort out whatever your problem is and/or decide where to land. I can't see the one in my aircraft, so am unable to visually check for air, but I do routinely check both the dashboard indicators (LED, flashing) and the switch. FWIW they are more usually piped up now with one incoming at the top, and one outgoing breather (also at the top) to avoid captive air pockets in the tank. And in my aircraft the bottom of this tank is the low point in the system and has an external bleed valve. Outgoing fuel is taken from a point just above the bottom of the tank.

I have XCom, works fine. But Becker are good gear and the quote above would definitely be worth following up!

I think he's looking for a detailed drawing, with dimensions, for the firewall, Mark? zapora translates as dam, and zapora ogniowa is firewall...according to Google...

Supplied with kit.

Hi Skippy, yes the Savannah has carbie heat (or more accurately, warm air to the carbs). The rectangular aluminium box you see there is the air box, with air filter. The inlet tube to the right aligns with the NACA scoop in the cowl, and as you can see in the second pic, I have extended it by attaching a sheet aluminium tube with a hose clip. The inlet tube to the left, with the scat tube attached in the second pic, is the warm air, collected from behind the engine muffler. These two inlet tubes have butterfly valves in them, 90deg out on the same pivot, so when one is open the other is closed. You can see them in the first pic. It works fine, with a little attention paid initially to the moving parts to get positive valve action. It doesn't deliver super hot air and the collection point below does need positioning to maximise that. Also the temp sensor in the airbox has some thermal mass and is quite slow to respond, which is fine once you get used to it: you get warm air straight away (provided the muffler is hot) but it doesn't show up immediately on the temp gauge. I don't notice a big difference in engine power with and without. I don't have any pics looking down on the cowl. You can just make out the NACA scoop on the top of the unpainted cowl in the first pic here. The second pic shows a side view of the insides.

As a side comment here, the Savannah, which has an air box with temperature probe, has a NACA scoop in the cowl top for cold air. This works fine in normal flight, but not so much in a hard climb, where I was seeing rising airbox temperatures indicating that air was being drawn from under the cowl via the 30mm gap between cowl scoop and airbox inlet. I was able to correct this with a simple aluminium extension clamped to the airbox inlet (while still leaving a small gap to drain rainwater while parked).

It's a small pad, or other sort of grabable item, either velcroed onto the back lower corner of the pack, or tucked in under the pack flap there, but protruding. In the video, you can see it blowing around on the jumper's right at about waist height. It is attached to the apex of the soft pilot chute, so that when you drag it out the pilot chute remains collapsed until you let it go (preferably at arms length to get it out of the burble over the jumper's bac)k. The pilot chute is attached to the umblical cord, a simple loop of which is acting as a soft pin holding the backpack shut; from there it is attached to the canopy. So releasing the pilot chute, allowing it to inflate, both opens the backpack and drags out the canopy (which is usually in some sort of soft sub-container). The development was interesting. For years after WW2 we had: 1. Ripcords with pins that threaded through metal cones on the backpacks, and bungies on the pack flaps to encourage them to open. Various things could go wrong with this, (though fortunately not too often, if understood and maintained). 2. A two-shot system requiring both hands to unlatch a mechanical assembly in two distinct steps at the shoulders in order to cut away, or jettison, the main chute. This was a military innovation, developed to prevent airborn troops being dragged on the ground in high winds, and never intended for freefall use. Used in a modified and slightly less clunky form known as a one-and-a-half-shot. It worked okay like this. and 3. We then had the arrival of low-porosity fabrics and square canopies, which opened much harder than round canopies, sometimes injuring and not infrequently knocking out the jumper. And in a period of 2 years, maybe less, all these problems were neatly solved: 1. Ripcords, cones, bungies and spring loaded pilot chutes gave way to simple soft throw-away pilot chutes (originally mounted on the waist band where you could see them.) 2. The modified military two-shot release was replaced by the simplest cleverest most reliable thing called a 3-ring circus, operated with a single soft handle (as seen in the video!) https://en.wikipedia.org/wiki/3-ring_release_system 3. The problem of slowing openings was finally solved with the simplest of devices: a slider, which is a reinforced fabric rectangle with a big grommet in each corner, a quarter of the lines being threaded through each grommet, and the slider pulled up to the canopy when packed. On opening, the canopy spreads the lines, but does this progressively instead of instantaneously as the slider slides down the lines.

Yep, Wirraway, it never made much sense to me having your main deployment where you can't actually see it. But then I was raised on ripcords, and the training routine was: look for the handle/ now come in and pull the handle. You can see with the guy in the video, he doesn't get to look: he just grabs something, and his muscle memory has him grab the cutaway pad... Yep, great jump ship the Pilatus, if a bit smelly and with a slightly queasy wallowing action when hanging on that prop in a steep climb. I never jumped one in Oz, first came across one at a Peterborough meet in the UK, where we also got to be 10 items of ballast when it was demoed to the military on a very windy day, so got to experience the vertical ride down as well as the ride up............)

Hey, Wirraway, did you ever meet Rod White from Queensland way? Some time way back, I arrived at Zephyrhills between rigs, to find Rod there but recovering from some ailment, and he kindly lent me his rig. Complete with bunny tail, which I was not used to, so I made a whole load of practise motions on the ground. But which made no difference at all: come opening time, I could not find the damned thing. I knew they could become detached and flap in the breeze, so after a moderate amount of groping, and with the telegraph poles starting to spread out, I pulled the reserve, and found myself under a small round dome: Rod had shortened the reserve lines so much to get it in the pack, it was like wearing a big hat. And it oscillated like crazy. On landing, I found the bunny tail still firmly attached exactly where it was supposed to be. When I apologised for dumping his reserve, Rod said that was okay, he had wondered how it would be, short lined.............)

Hi Mark, sounds like a win/win, and that's certainly a great looking rotisserie setup! For others who may be interested, I used a simpler arrangement, and it wasn't ideal, but could be made so: I used a rope attached at two points in the shed roof, crossed over itself and hung under the engine mount. To rotate the fuse, I lifted the weight of the front fuse just enough to loosen the grip of the rope and turned it. Once back on the rope, the friction of the rope held the fuse in the new position. 1. The main drawback with this was that the engine mount is not at the centre of gravity, so the fuselage suspended this way is very belly-heavy, and a lot of muscle was required to turn it belly-up (and I never did get it entirely inverted). Another time, I would make some simple frame (maybe a reel made of heavy ply bolted through blocks) to attach to the engine mount, allowing the rope to cradle lower down. 2. This did involve running the rope through slits in the roof of my spray tent, and I was concerned that this may shake loose dust. But I ended up topcoating the fuse in 4 separate stages (top, 2 sides, then bottom) and this was not an issue. 3. The rear fuse I had just resting on a padded sawhorse. Again, since I painted in 4 stages, this worked fine, but obviously this would not work if painting all in one go. 4. FWIW the Savannah fuse does lend itself to being painted in 4 stages, just mask along the skin edges. As an amateur painter, I found this more manageable. It's a lot of work however you do it. While I'm certainly glad I did my own, I also wouldn't look forward to doing it again! Looking forward to seeing what scheme you choose, Mark.

Sure. Just steer clear of them big magnets they use for pickin' stuff up in scrap yards.........

The Wankel-powered RO80 got NSU Car of the Year in '68, but subsequently finished the company: the early versions had so many rotor tip failure problems that owners would hold up how many fingers/warranty tip replacements they had had as they passed each other. It didn't help that one of the selling points was 'the faster you go, the more economical it is', due to the peculiar power curve: the autobahns had no upper speed limit, so RO80 owners drove very economically indeed. A pity, as it was a very advanced and well built car in many ways. More recently, there is still a strong contingent of Mazda rotary fans among the petrolheads. And I have to say they sound great when they're going. But I'm also told they are forever needing to rebuild them.

"Wretched pilots keep complainin' of running out of elevator trim. Right....we'll fix THEM..................."

There is also a story about a loader driver who got his own back by clambering somehow into the hopper midflight, and hiding there after landing. But, of course, nobody would be so silly as to do that nowadays.........)

Oh dear.........( The Airtruck had a tiny dicky seat at the rear of the fuselage, for transporting loader drivers and other unfortunates; and from which, on turbulent days, the long-suffering loader drivers had a clear view of the twin tail booms, as they wobbled about independent of the aircraft and each other....

I'm just pi**ed off that I could have made do with a couple of barn doors, instead of 7,000 rivets and aluminium origami.........(