IBob

A simpler option (certainly when building) would be to remodel the bracket to tilt the stick forward a bit. It would mean moving the pivot point a bit forward and adjusting the sweep and position of the quandrants to ensure correct mixer movement, so would mean making new brackets. But it shouldn't be hard to sort out.* The reason I like that option, and the reason I stuck with just modifying the stick Is that, apart from stick angle, the mechanism is simple, safe and works very well. The innards do need to move freely, almost rattly loose, as the latch mechanism relies on the spring under the button. So the usual thing when setting flaps is to give the stick a wiggle to make sure it is solidly latched. I have also seen situation where the rubber grip has moved up on the handle and is starting to foul the button, so the grip needs to be well anchored. *Maybe a little job for Mark..........in his spare time.....😆

Shafs, I'm of average height, so seat fairly far forward, and I found pulling full flaps on the standard lever very clumsy: instead of pulling up on the handle, the last notch was pulling back into the stomach. That and incident reports where improperly latched flaps have caused a few frights and sometimes major damage, and I decided I needed to do something about it. It took a while to decide on how to do the internals, but turned out to be very simple, just needs to be made fairly precisely. I had help with the fabrication, my DIY abilities come nowhere near welding stainless. The angle in the shaft is just 12degrees, but for me it has made a huge difference. PS note also Mark's excellent 3 position flap bracket in place of the standard issue 2.

Looking really nice, Mark!

And here is a the A/B/C pinout: https://duckduckgo.com/?t=ffab&q=pinout+of+rotax+oil+pressure+sender&atb=v356-1&iax=images&ia=images&iai=http%3A%2F%2Frepairguide.autozone.com%2Fznetrgs%2Frepair_guide_content%2Fen_us%2Fimages%2F0996b43f%2F80%2F20%2F27%2F4c%2Fmedium%2F0996b43f8020274c.gif

Okay, so I found this, which suggests that they are using a 2 wire current loop setup: https://duckduckgo.com/?t=ffab&q=pinout+of+rotax+oil+pressure+sender&atb=v356-1&iax=images&ia=images&iai=https%3A%2F%2Fdesk.zoho.com%2FDocsDisplay%3FzgId%3D714941653%26mode%3Dinline%26blockId%3D1hflqdbff7005142a40f9ac47410e66c421a2 It says that Pin A = n/a Pin B = 8-24VDC (12V in our case) Pin C = Signal And here is how it is wired to the gauge: https://duckduckgo.com/?t=ffab&q=pinout+of+rotax+oil+pressure+sender&atb=v356-1&iax=images&ia=images&iai=http%3A%2F%2Fwww.aviasport.com%2Fimages%2FConexiones_OIL_P_4_20_57.gif Danny, I found that by searching 'pinout of rotax oil pressure sender'.

Agreed, Nev: if buying from a transducer manufacturer or supplier, it would all be on the data sheets. But Rotax have gone to their own numbered part (albeit manufactured by others) so unless we have a non-Rotax part number for the unit, we're guessing a bit. Unless Rotax have published details somewhere.....they may have.

Danny, as I recall, my engine came with the sensor/sender (we just used to call them transducers) fitted, with the plug and cable attached. The cable would have been marked, so no need to meter through to the plug pinout. If all else fails, maybe you could find someone with a new uninstalled engine, and get them to meter out the cable/plug for you.

That's correct, Skippy. Think of it as a diaphragm, with one side to atmosphere, the other to oil (or fuel) and it is measuring the deflection in the diaphragm. The key element is that oil pressure is atmospheric + pump pressure, so you are measuring that against atmospheric pressure. So as you climb, the atmospheric pressure should decrease on both sides of the diaphragm, but the differential pressure (and diaphragm deflection) remains the same = accurate reading. If, however, the atmospheric pressure falls as you climb on the oil/fuel side, but remains at ground level pressure on the other side (due to being sealed) then you get an increasingly inaccurate result.

Danny, these sensors are differential: they should measure the difference between the oil (or fuel) pressure on one side, and atmospheric pressure on the other. Your oil pressure is atmospheric pressure + pump pressure, and is measured against atmospheric pressure. So as you climb, the atmospheric pressure falls, but the differential pressure remains the same, so you continue to get an accurate reading. But If the sensor is sealed on the atmosphere side, then the atmospheric pressure is falling as you climb on the oil pressure side, but remains the same on the 'atmosphere' side. So you get an increasingly inaccurate reading. And in the case of Skippy's fuel pressure reading it would make a huge difference.

Ah right, Skippy, that would be much more of an issue: the oil pressure unit is 0 to 10bar, mine sits 5 to 6, but the fuel pressure is 1/3bar or less, so if the unit is not correcting for altitude, you would see little or no fuel pressure at 10,000'. I have seen the same problem now, twice, with fuel pressure steam gauges, where the builder has not removed the shipping plug from the gauge body.

That's an interesting one, Skippy. Given that 10,000ft sees approx 30% drop in air pressure, if altitude is the problem you would see approx 1/3 bar error at that height...not much, given that my oil pressure normally sits over 5bar.

Nev, could you explain about the rings not bedding in and so burning more oil? I'm not disputing this, I would like to understand it better. Thanks.

Hi Pat, it looks as though they made all the required changes to turn the Classic into a VG, as per ICP factory designs. Perhaps this was necessary for certification. I don't think that has much to do with removing the slats and adding VGs, though my understanding is that ICP made a small change to the wing leading edge profile when they took that step. An excellent source of information would be John Gilpin at Stolspeed: https://www.stolspeed.com/slats-v-s-vgs

It is what's called a current loop device, they commonly come in 2 and 3 wire versions and are an industry standard. Instead of behaving like a variable resistor, it puts out a current between 4 and 20mA. This one has a span of 10bar, so 0bar = 4mA and 10bar = 20mA. The 3 wires are 0V and 12V to power it, and the third wire is the 4-20mA signal. The reason for using current as a signal is that it can be connect with a short or a very long wire and it makes no difference. Voltage, on the other hand, will drop with a longer connection, due to the resistance of the wire, giving an inaccurate reading. However, the reason for the change in these Rotax sensors was that the old VDO sensors had an unacceptable failure rate.

Hi Pat. Lots of good Savannah info here. And no shortage of opinions, either! Not sure why removal of slats would require structural reinforcement, will be interested to hear what you find out.

Note that if you have steam gauges, you cannot connect this newer type of sensor to the older style VDO gauge. The correct steam gauge is this one: https://www.aircraftspruce.com/catalog/inpages/cps15-06649.php?clickkey=64183

I pulled my windscreen back too tight at the top centre, Mark, with the result that it dented in there far too easily. The fix was just to let it out...a surprisingly small amount, like about 2-3mm at the centre, progressively less towards the sides...which then gave it a curved 'brow' and the right shape to withstand the prop blast. Fortunately, there was enough material there to do that......

BrenDan I did part of my training in Technam P2002s, they had a centre throttle and one on the left side. (I flew on the left, but tended to use the centre throttle, as it was next to the trim switch, though trim may have moved to stick top buttons now. Then I built, during which I flew very little, and had to swap hands once the Savannah was finished.) So you may find Technams out there with a LH throttle, maybe make a few calls?

Yes. If he's using the ubiquitous Ray Allen trim servo, the limit switches are built in. What aircraft is this, RHTRudder?

RHTRudder the basic arrangement in microlights is usually a Double Pole Double Throw (DPDT) switch with 6 terminals. This is the trim switch on the panel. Internally it is two separate switches, mechanically linked (DP). The switches have a central neutral position and, up and down active positions (DT) with spring return to the neutral position. They are wired so that when the switch is up, the two wires going to the trim motor one polarity (eg 12V/0V) and when down that polarity switches (0v/12V). This drives the trim motor in one direction or the other. Here is how they are wired:

Tank flow conflicts are unlikely to be a factor at normal fuel feed rates.

Hi Rooviator, I suggest you also check for fuel line undulations, and filler cap seals.

MKennard, where two pipes are siamesed together, the flows collide. And depending on the dynamics of that, sometimes one flow beats the other one out, so the stable state is not flows combining, but one or the other 'winning' and excluding the other. I would expect that effect to be far less, if at all, at low velocities. So it may be that draining the tanks as you describe is not what will happen at slower flow rates.

Mark, another option would be this, also makes for a more natural pull to full flaps, so we shortasses aren't trying to press the lever into our gonads:

I did some work on my Savannah to get more even fuel flows. Two things stood out: 1. The individual tank vents may deliver different pressures to the tanks in flight. The Savannah vents are rislan pipes sticking out under the wing, and normally cut at a 45deg angle. I was able to adjust these by altering the angle of the cut. A very small difference in pressure will make a big difference. Cessna get round this by having just one vent, then cross-porting the upper tanks. Were I to build again, I would look at doing this. 2. Undulations in the fuel lines from the tanks. These can capture air at the high points, greatly impeding fuel flow. And this will change, giving varying results depending on the changing amount of trapped air. I went to some lengths to straighten my lines. Note: I suggest you also check the filler cap seals: if they do not seal properly, then any pressure from the vent system will be lost, resulting in uneven tank pressure and fuel feed. And finally, I am told by experienced pilots that most aircraft have some degree of uneven fuel feed.