skippydiesel

I see this idea promoted quiet a lot on the Rotax Owners Forum. Cant see the need myself. At the rate I accumulate hr's an oil drain only happens once per annum, in a good year a possible second. Hardly a challenging workload. The drain plug should not be tightened any more than necessary to crush the washer (Rotax will have some ridiculously low torque setting , wrist "click" will do me)- easy to see & do. The plug is then safety wired to the base of the tank. - no chance of comming undone.(I have never had a leak from the oil tank). Removal is a doddle - remove safety wire and using two spanners "crack" the lightly torqued plug. Its now finger tight but a tad hot to actually use the fingers, so continie to loosen with one spanner. Put your old oil receiveal container up as close to the bottom of the tank, as is constant with doing the job/access - this will reduce the chances of spillage. I use roofers soft aluminium flashing (Bunnings Aerospace) formed into a channel & hooked over the engine frame, to direct the oil into a calibrated container (I like to record oil quantity removed, then added). It's annoying but of little concern if the plug drops into the hot oil - magnet will fish it out. I am not against the oil drain valve - have one fitted to my Ranger sump. The Ranger requires removal of bash plates, before loosening the drain plug and then the position of the drain means oil hits a cross chassis member & splashes everywhere (nasty!). The drain valve & short hose prevents, all that mess & the need to remove bash plates- a no brainer!😈

If anything the airbox arrangement makes carby ice more likly, than conical filters sucking warmed air. As you noted, the manifold heaters (claimed to prevent icing) are part of the existing system. My last 912 with just conical filters, never even hinted carby icing. (This is not a claim that Rotax 912's do not experince carby ice) When I was trying to isolate the cause of my leaking carby bowl breathers, I ran the Rotax conical (pod?) filters - no leak. Hot inlet air, will have some (?) performance loss implications. I agree, likly small, however this is not the only consideration. A lot of work & cost, went into the existing air box. One of my flying objectives - economical (fuel used for NM covered) touring, so no unnecessary fuel consumed (throttle setting). Together ,this means that it would take a genuine safety or performance issue, for me to ditch the airbox. The photo I posted was of the unfinished item - now looks a lot more professional, sporting a black satin look, heat resistant, ceramic, finish. I have no complaints about the airbox performance - now that it's not using the carbys for part of its support system. The clearances, due to limited space, is a minor problem that only impacts on my choice of airbox to carby duct, the topic of this thread /discussion😈

BurniM & RossK, Looks like the same iPad bracket that I had in the Zephyr - worked well. I did modify it a bit, by drilling extra holes in the back to facilitate better air flow from the eyeball vent - don't actually know if this improved things or not, as the fitting of a dedicated vent coincided with cooling mods - no further overheating occured. I don't like suction mounting systems - they seem to pick just the wrong moment to let go. I do use them to place the device (?) in various locations around the cocpit, decide on the best, install a fixed ball for security.😈

Originally the airbox was mounted/supported on engine & both carbys - far too rigid. As you may know the carbys have a "rubber" inlet manifold section, specifically to minimise the effects of engine vibration & movement on the carbys. The above arrangement was effectively negating this system. The airbox now has two supports on engine itself - one a vibration isolator, the other a saddle - the idea being the airbox weight is no longer on the carbys but still moves with the engine. Not sure but think the Rotax OM airbox & ring gear are attached. The airbox is far enough back from the carbys to have a longer /more flexible connecting duct/hose. To minimise the potential for restricting the inlet manifold rubber flexing a very flexible duct/hose between carby and airbox needed to be found. SCAT, with wire in place, was tried however the small gap (10-15mm) between airbox & carby meant that the wire effectively removed the ability of the two fixtures to move independently. Removing the wire solved that problem. I do not believe there is a risk of the existing modified SCAT comming adrift - I have had one significant engine start/movement event - duct stayed in place. My last aircraft ATEC Zephyr, used the two conical Rotax filters - worked well. (Maxed out at about 125 Kt - Normal /Eco Cruise 100-110 Kt Indicated) The Sonex is a significant step up in performance - outside/cool air supply to the engine, is part of this. (Max Cruise 152 Kt True - Normal/Eco Cruise 130 Kt True)😈

Onetrack, "......airbox that doesn't have a satisfactory connection arrangement to the carburettors." Satisfactory?? depends on what you mean. The solution I have works, it's just not as elegant as I would like. As a whole the engine installation, is what it is - it actually works very well - not perfect but then what is? The not insurmountable problem (carby to air box ducting) is "chicken feed" in the scheme of homebuilt problems that can arise. I have a working fix that has served successfully or about 100 hrs now. I did replace it at the 200 hrs service , as I don't know how durable it may be over time. Certainly I would like a better fix - a durable hose/duct similar to SCAT but without the reinforcing wire. I don't like modifying the SCAT - I am concerned by the potential for damaging the fabric and the much lesser esthetic result (looks unprofessional) As mentioned earlier, Sonex have recently come up with a Rotax 912 adaptable "ring mount" engine , which would likly result in a far better/more space in the engine bay - way to late for my build which has now been flying for 200 Hobbs hours.😈

It actually works very well - Appearances, lack of convention, whatever is spurring you to make negative commentary, is jumping to a conclusion that you have no practical basis for.

Hi BurnieM, I apologise if I didnt not articulate my need in a more comprehensive manner. My airbox is a home made unit. It features a forward facing "horn" to the front R cowl inlet (fresh, cool, possibly pressurised air) My Rotax 912ULS is installed in a Sonex using an Aerovee/Rotax adapter - makes for very tight engine to firewall space (Sonex have recently come up with a Rotax style "ring mount".) The duct that I am discussing is between airbox & carburettors. The space between carby inlet & airbox outlet, is about 10-15mm (not counting the mounting flanges ). Previous ducting was a thick walled "rubber" hose. I had a problem with the carby's ejecting fuel, from the float bowl, through the bowl breather. After much trial, error & debate (mainly on Rotax Owners Forum) the fuel problem narrowed to the carby vibration/movement isolators being impeded by the connection to the airbox. The solutions; # Take all airbox weight off carby(s) # Fit a more flexible duct between airbox/carby, has worked. The more flexible duct, I am currently using is the aforementioned, modified (wire removed) SCAT . The wire removal damages the fabric. Great care is need to avoid punctures (wastage). After wire removal the surface looks a bit tatty & may have been weakened. My only reason for raising this topic is in the hope that someone can recomend a SCAT like ducting, that would deliver a better more durable finished product.😈 This is a build stage photo (now has Hobbs 200hrs) shows test fit of airbox & inlet "horn" Note: how close air box flange to carby flange.

It could be my imagination - have we come full circle back to RAM Mounts. I had one for my iPad in the Zephyr. Went "out" on overheat twice (in winter) before I fitted a dedicated eyeball vent, delivering cool outside air to the back of the cradle/ipad. I now have one in my Sonex, for my back up GPS - if need be can be cooled by Pax vent. The iPad is in a fan cooled dock on the panel. The iPad panel dock looks the goods/professional but is actually not as adaptable as the RAM system, which can be adjusted to suit the pilots or pax view but for reading issues like glaire. . 😈

Possible. All the silicon hose, I have seen, is pretty thick walled/heavy stuff - I doubt a 10-15mm gap would allow much movement.😈

Moneybox, "I I did see somewhere it mentioned up to 20kt cross wind." A 20Kt X wind component would be unusually high for small aircraft like yours. Your POH states 10Kt for TO/Landing. I would go with this and not try to "explore the envelope" in what can be a challenging flight situaton, with very little room for error. The most challenging X wind is a blustery one, it's there, then gone, then back - the pilot is fighting to mainatine straight & level while slipping on/of, into wind - not fun! Aircraft types may have very diffrent handling characteristics, in X wind landings, from relativly benign to scary. 😈

Please expand - particularly on ".......so hard to find the right heading without compass or the GPS aides." No offence but it reads like you may need some nav. refresher training.😈

That's great! So why the concern about iPad / magenta line, reliability and inability to establish a heading? I have never flown in WA, it may be a little like western NSW (where I did all my GA training). In the pre GPS era, I was comfortable, in what the city VFR pilots called features terrain. I moved to the Sydney Basin, had to have a local pilot with me for the first few flights - I couldn't see the landmarks for the buildings. Its what you get used to. I was trained to take heading notes. While heading will change over time, the failure of devices (compass/heading indicator & now EFB/GPS) should not be anything more than a minor inconvenience . The X country pilot expects not to easily recognise subtle features - fly your heading. Horizon indistinct - fly your heading. Your last heading, will likly get you to some feature, that will allow you to reorient (if necessary).😈

Sorry Moneybox - No excuses. If whisky compass a dud, get a new one. If OzRunways not giving heading info, reconfigure screen. Hand held (back up) GPS not very costly, in the scheme of aviation related costs. Pencil & paper is your freind. For you & your Pax safety, some form of reliable backup(s) is essential on a navigation flight outside your usual "home" range. Fly safe.😈

Hi Moneybox, "I don't trust the iPad " You shouldn't trust any device, that may let you down in flight. That's why you have a paper flight plan, with all the necessary information to complet your flight safely. Your flight plan should be updated, in flight, with any changes to heading, altitude or flight time, so that a failure of your EFB will have little if any effect on the continuation of your flight.😈

If you can find someone with a laser printer, they can make you amazing labels - almost any shape, colour, font, size, you might imagine.😈

Ha ha! The hose/duct need not be self "supported" because the gap between the carby & airbox is only about 10mm. Due to the short distance, the wire ribbing of the SCAT gets in the way & restricts some of the relative movement that needs to happen. Temperature Range - From ambient Australian east coast winter, say a rare 0C, to summer, under cowl , post engine shut down 80C. In operation the undercowl temperature is a consistent +10C above ambient. The duct will be supplying outside air, from the air box to the carby(s), so there is the potential for -C (?) temperatures at altitude.😈

If such exists- SCAT, without the wire would be perfect. Something along the style of lightweight lay flat hose. 😈

Thanks Onetrack, A quick brows would suggest that the ducting is either wire reinforced (too stiff) , to large an ID or has insufficient heat range for safety. Thanks for trying 😈

Ram Mounts are the way to go. If you locate in front of an eyeball vent, no problems with overheating. 😈

Is that a question or a statement? If so, to whom is it directed ?😈

Speculation; I think a trip into town, would find 98 RON. Likely far cheaper than an airport mobile supply service😈

Already done the satellite view - With the exception of the grass, & gliding facility, unable to ID any of the features you have mentioned. Even "the terminal building" not so labeled - could be a shed for all I know. Dexter Burkill - Seems to have been impressed by a toilet on the site "Pretty quiet airport like many regional airports. Clean and tidy rest room". Of course I am assuming "rest room" is American jargon for toilet/dunny/lavatory and not a room with beds in. I still can't understand why such a significant airfield (as in good sized sealed runways, facilities, nearby town) has almost no information in ERSA, Ozrunways/Pilot Notes - ZIP!😈 😈

Thanks Onetrack - I was more surprised than anything at the brevity of information in ERSA & ZIP! in OzRunways. If I decide to attend the Fly-In I will certainly follow up on the contact details you have provided and also with the organisers. Thanks again. 😈

SF Gnome - I suggest joining the Rotax Owner Forum - you won't regret it. Great for solving all these little Rotax problems. https://www.rotax-owner.com/en/rotax-forum 😈

I have an oil thermostat - yet (never?) to fit. At a guess, I would suggest, if at all possible, prefiling all hoses & heat exchanger ie minimising air pockets. I would do this anyway when replacing hoses (5 Year Service) etc FlyBoy1960 suggestion sounds good but I would be concerned the wax pellet would be rapidly cooled by the cold oil, closing the thermostat - perhaps heat the oil to 100C. "When cold, the radiator is bypassed" Are you sure ?- In my limited experince, thermostats do not completely cut off supply, rather divert the bulk of cool liquid around the heat exchanger, back to the engine. If I am correct - bleeding the lubricating system, as per Rotax manual, may still be possible😈