IBob

That's odd: it's different in NZ: Part 91, General Operating and Flight Rule. CAA of NZ 91.313 VFR cruising altitude and flight level (a) A pilot-in-command of an aircraft operating within the New Zealand FIR under VFR in level cruising flight at more than 3000 feet AMSL or 1000 feet AGL (whichever is the higher) must, unless otherwise authorised by an ATC unit, maintain the following altitudes or flight levels: (1) when operating at or below 13 000 feet AMSL and— (i) on a magnetic track of 270° clockwise to 089°, any odd thousand foot altitude AMSL plus 500 feet; or (ii) on a magnetic track of 090° clockwise to 269°, any even thousand foot altitude AMSL plus 500 feet. I'm guessing that's because we are a long country lying on a roughly N/S axis, so most traffic would be travelling in either a northerly or a southerly direction.......

There was a dealer, in the Netherlands I think, offered a new one to anyone who could roll theirs (on the flat and without striking a kerb). Supposedly some guy finally managed it in reverse: being front wheel drive all they do going forward is lean at an amazing angle before the back slews round. I can't think he actually rolled it though........more likely it ended up on its side.....)

Two things about the Citroen 2CV: 1. In the 60s and 70s adventurous young folk started to do very big road trips out of Europe.....down and round Africa, over and round India, then back up round the Med into Europe. It was a thing to paint a map on the door of the car, showing the route taken...and some of those maps were really impressive. Of course, you only saw the maps on the cars that made it all the way round....and they were, in no particular order, Land Rover, VW and Citroen 2CV. 2. We once swapped cars for a long weekend with young friends: they had family visiting, and needed more room/seats than their 2CV. So we had the 2CV for the weekend, and it really was one of the most enjoyable weekends of motoring I ever did. Something about the way the thing rode and handled put a big smile on our faces, and by Sunday we were taking folk from the drop zones for rides to spread the joy. The body of the thing seemed quite independent of what the running gear was doing, and at times it was more like sailing in a stiff breeze than driving. If they weren't now worth silly money, I would have one just to relive that.....)

Thanks, Red. I baled on Facebook some years ago when I realised it was making me ugly(er)..........(

Cant access that, Red.......(

Not one of these, by any chance? Or was it definitely US hardware???

hi Mark, I followed your lead on the fuel vales for SVA, have them mounted on the pax side where I can see them, works a treat. I made up some sort of bracket with scrap, and ended up attaching the manifold block with a couple of cable ties, it's absolutely solid. As for the headphone jacks, that's a bit of a puzzle: mine were on the floor console, which is a terrible idea, I recently moved them to a box between the seats at about shoulder height, which is a lot better but still feels a bit clumsy......

Hi Peter, I just PMed you a response as your original post was throwing some strange error here. But it looks to be okay now. Here is what I sent: I am 5'8" and fly my Sav S with the adjustable seat one notch back from fully forward. I found the standard flap handle very awkward, to get full flaps I was not pulling it up, I was pressing towards my stomach, which is not a strong physical action. So I found it clumsy both putting flaps on, and taking them off when doing circuits. Add to this that improperly latched flaps have been known to drop out suddenly, causing considerable aircraft damage in one case that I know of. So I fabricated a new handle with a 12deg bend in it. It works exactly the same as the standard one and addresses all the above problems, I am very pleased with it. However, I was fortunate to have an engineering buddy do the necessary SS cutting and welding for me, it needs to be made precisely and it is not something I could have made on my own. I have provided sketches to other builders, but to my knowledge nobody else has done this. What they are doing here is ditching the ICP handle system entirely, and fitting a slightly modified car handbrake: I believe it is the Suzuki Swift, but I would need to check that. They then grind teeth off the handbrake ratchet, leaving themselves with 3 flap positions (I have the Mark Kyle flap handle mount that gives 3 positions, which I think is a worthwhile change). Since a handbrake only locks in one direction, they then add a spring or bungy so that the flaps do not fall under their own weight while taxiing or parked. I'm in the N Island in NZ, most of the builders in the S Island seem to be going the handbrake way. If you are interested in pursuing this, I could put you in touch with one of them.

Yes. So I wonder if the radiator has internal riser pipes, so the oil is arriving and leaving at the top, even though the external ports are at the bottom. I did a quick search, but was unable to come up with any part number or detail on the radiator they are using.

So it does! I don't understand why the oil would not pass across the lower radiator cores and out the other side, without displacing air that may be in the upper cores? Unless there is something tricky inside the radiator, like internal riser pipes from the ports???

Yep: many years ago the very experienced GA CFI of the aero club (where I lived, not where I am now) collected the fence on approach when someone gave him a go in their brand new microlight.....(

How about opening the oil inspection hatch on shutdown, to avoid the heat soak in the first place?

Skippydiesel, that is the standard installation for the Savannah kit of the time, but with a great deal of fine engine detail taken from pics supplied by Reg Brost, the Australian agent I bought the kit from. I hadn't realised how valuable the pics would be until I got well into the build: I worked latterly with an old laptop on the bench so that I could refer to them, also fire off questions from time to time to Reg and other builders. I have no way of knowing how that setup would perform in the conditions you mention, but generally speaking it seems to me the Sav fuel system is very well thought out. If your Zephyr had a pressure relief valve it perhaps would not have vented gas buildup as effectively as a fixed aperture. And it's worth noting that, since the dynamic viscosity of gas is much smaller than the dynamic viscosity of liquid.... while the fixed aperture returns only a small volume of fuel (I've not measured it, but figures like 2L/hr are quoted) it will return or vent gas far more rapidly: hopefully you will find it works very well indeed. The other factor that occurs to me is that much of the fuel system, including the hoses, has fairly low thermal conductivity. What that means is that it does not heat through quickly.........but once heat soaked, it will not cool quickly either. Furthermore, the hoses are shrouded in a protective sleeve, so not well able to dissipate heat. And what that means is that, with a hot start, it is probably the fresh fuel passing through the hoses that cools them. Initially, that may make more gas. But provided that can be vented, the system should flood and stabilise. Keep us posted!

Skippy, I believe I can see what you are getting at: If the lines to and from the Rotax pump were under the engine, they would be less likely to heat and gas (in a static heat-soak situation) in the first place? That seems reasonable to me too. However, with my installation, since cold air comes in to the top of the engine and passes down over it, this would place the lines in a warmer place once the engine was running. So there appear to be pros and cons with each of the two arrangements. In my circumstances, I am comfortable with the arrangement I have. But your circumstances are clearly different, and given your account, I can see where you are seeking to reduce the chances of a repeat. Can I ask what the layout of your fuel system is in the engine bay, the various components and the location of them? It would also be interesting to know how your fuel is piped from tanks to engine bay. Attached are pics of my layout: The aux pump is behind the square white shroud at lower left of the firewall. The splitter is just above the shroud and to the left (against the firewall secured to the engine mount with a cable tie). You can see the line to the LH carb, with filter, coming forward from it.

Skippydiesel, I have experienced vaporisation of fuel in the engine bay lines twice that I know of, both during an engine restart some minutes after shutdown. So the engine bay would have been heat soaked. Since part of managing this depends on the configuration of the aircraft, here is my (engine bay) layout: The fuel line runs forward under the aircraft belly, and is piped into the bottom of the aux fuel pump, which is located low on the firewall and fitted with a shroud which is open top and bottom. From the top of the aux pump, the fuel is piped up and forward over the top of the engine, to the Rotax fuel pump. From the Rotax pump, the fuel is piped back over the top of the engine to a splitter at the firewall. The splitter has four ports: one for each of the carbs/ a single port with small orifice for 'fuel return': this is piped back to a point high on the RH wing tank/ a single port with a small orifice, piped to the fuel pressure gauge. Here is part of my standard startup routine, and how the vaporised fuel affected it: Check tank levels/tank select valves/emergency shutoff valve. Power on. Power on aux fuel pump and observe fuel pressure rise to > 2PSI. Normally the aux pump runs at a slow steady rate, and the pressure rises promptly. However, with vaporised fuel, the pump 'chatters' at a high rate for 5 to 10 sec before settling down to a steady rate with the fuel pressure then rising. What is happening here is that the vaporised fuel is being driven through the orifice of the return line, and back to tank. Power off aux pump and observe fuel pressure drop to zero. (This verifies that the fuel return orifice is not blocked: there is a check valve in the aux pump, if the return line is blocked, the fuel pressure will not drop.) Start engine as normal. Cool air is now moving over the upper engine. Do not take off immediately. Allow time for cool air and flow of fresh fuel to cool fuel delivery pipework etc. NB: It should be noted that the fuel return line, with orifice, is piped back to a main fuel tank. There are several accounts online (including of an EFATO with inversion) where the operator has piped his return line to the gascolator in the engine bay. All this does is recirculate vapor and hot fuel in the engine bay, rather than flushing them back to the tank.

Skippy, it aint (taboo). You're having it (a discussion). I have nothing to add, maybe others will.

Aye, well, I've said my bit. I'll only add this: in the carburettor function description, also linked above, the authors spell out how they go about troubleshooting carburettor problems. Specifically, they go looking for what has changed since the factory assembled the engine, and they then put it back as per the factory assembly. That seems like solid advice to me.

Skippydiesel, since we don't seem to have a problem with the fuel lines located where Rotax usually put them, I'm not sure what you are trying to achieve that has not already been achieved. Convection, which you mention, is only a factor with the engine stopped: for most engine installations, the cooler place will be on top of the engine once it is running. Sure, there may be a better routing to reduce gassing as a result of a recently stopped engine...but since you say you are well aware of existing strategies to deal with that, what is the issue here?

Skippydiesel, looking at the illustration in the article, and assuming the cap screws are equally spaced, it would seem to be feasible to rotate the cap as you suggest. Three things to consider, that I can think of: 1. We don't have a torque figure for those screws. 2. Opening the pump voids the warranty. 3. Engine heat soak causing vaporisation is best dealt with by a) Installing the Rotax recommended fuel return line with orifice, which will vent vapor back to the fuel tank/s and b) implementing engine start and preflight routines that will both expel any vapour and allow sufficient time to cool the engine bay.

Area-51 thanks for the heads up......yes, excellent articles! For anyone else interested they are: https://electricmotorglider.com/2017/02/01/bing-64-cv-carburetor-part-1/ https://electricmotorglider.com/2017/03/01/bing-64-cv-carburetor-starting-carb-part-2/

Maybe the guy alluded to in the Rotax article, Yenn? I guess it's a matter of being able to visualise the operation. I'd say it's a good candidate for a simple animation.

I just looked through the new article on the operating principal of the Rotax 912 fuel pump: https://www.rotax-owner.com/en/rotax-blog/item/77-rotax-912-fuel-pumps This details how the pump delivers varying amounts of fuel, on demand, but at (approximately?) the same pressure: I had assumed it would use a spring loaded overpressure bypass valve with more or less fuel being bypassed (like the oil pressure system) but it's not like that at all. It may not be new, but it was news to me, and I thought it very clever.

PS that really is a poor illustration on Page 20. The description specifically states that the oil level must not be more than 400mm below the Z axis............but the picture shows the oil level (2) below that.

Okay, saw your pics now. I am certainly not any sort of engine or Rotax expert, but I cannot see any problems with the way you have it mounted. I would think that the Rotax reference to having the ports on the top is to avoid anyone having them on the bottom, which would/could lead to varying amounts of air trapped, and the oil passing only through the lower part of the cooler, resulting in varying and inadequate cooling.

Skippy, maybe we are looking at different documents, but I can't see anywhere it says the cooler must be mounted in that orientation. The only references I can see are on Page 22 of 79-00-00: 1. Mount the cooler below the oil pump. 2. Mount the cooler with the fittings upwards. If I'm missing stuff here, I'm happy to be corrected........?