Captain Posted September 21, 2012 Share Posted September 21, 2012 G'day All, I have only ever flown with engines that used Avgas. Where do you source fuel and what arrangements do you make to get fuel easily if you have a 912 or 914 on a long cross-country and therefore need ULP or PULP? Regards Geoff Link to comment Share on other sites More sharing options...
Wayne T Mathews Posted September 21, 2012 Share Posted September 21, 2012 I can answer that with confidence... (writen with what is supposed to be a Scottish accent) "I don't know." Link to comment Share on other sites More sharing options...
Ultralights Posted September 21, 2012 Share Posted September 21, 2012 just use avgas till you get back home. 1 Link to comment Share on other sites More sharing options...
Tex Posted September 21, 2012 Share Posted September 21, 2012 ^^^ What he said ^^^ I have noticed some orangeish build up on spark plugs from the lead.... Link to comment Share on other sites More sharing options...
Ultralights Posted September 21, 2012 Share Posted September 21, 2012 i have noticed the same, and a yellowish exhaust staining on the bottom of the aircraft from lots of ULP use, i reckon its the yellow dye used in the premium unleaded... dont get it with the Avgas, just the nice old light grey tinting in the exhaust. Link to comment Share on other sites More sharing options...
Doug Evans Posted September 21, 2012 Share Posted September 21, 2012 will use what ever is there but perfer Avgas in my two stroke ! run much cooler more responce engine much happer been doing it in 229 for over 11 years without a single problem Link to comment Share on other sites More sharing options...
rdarby Posted September 21, 2012 Share Posted September 21, 2012 Carry a jerry can and go into town and fill it up. I have found small towns are happy to send someone out in a car to get you, even if only for $50 in fuel. Cheers, Ryan Link to comment Share on other sites More sharing options...
Captain Posted September 21, 2012 Author Share Posted September 21, 2012 just use avgas till you get back home. Thanks UL & others that replied, I don't find it all that attractive to have to spend time at each refueling stop to traipse into town, nor to call up favours from the local servo each time you land. So if you had no room to carry a Jerry Can would you be prepared to use AvGas in a 912 or 914 for a long fly-away trip ........... say 30 - 50 hours of flying without giving it a gulp of PULP? Regards Geoff Link to comment Share on other sites More sharing options...
Doug Evans Posted September 21, 2012 Share Posted September 21, 2012 Would be good for it they are designed to use both with no problems ! Link to comment Share on other sites More sharing options...
Alpi Posted September 21, 2012 Share Posted September 21, 2012 Hi Geoff This is what Rotax has to say about your query: Avgas places greater stress on valve seats due to the lead content and forms deposits in the combustion chamber and lead sediment in the oil. It should only be used in cases of problems with vapor lock or when other types of gasoline are unavailable. The consequences of using avgas are as follows: Normal oil change interval 100hrs If avgas is used for more than 30% of time between oil change then the frequency of oil and filter change reduces to 50hrs. Sadly it dosent end there. If your overall operation uses avgas more than 30% of the time and you have a series 3 gearbox (overload clutch) then that gearbox inspection will be required at 600hrs and not 1000hrs. Other than those minor irritations you're good to go. Most 912 operators do 50 hr oil changes anyway. I am one of those which takes care of the occasions I use avgas. Hope this helps Greg 1 Link to comment Share on other sites More sharing options...
facthunter Posted September 22, 2012 Share Posted September 22, 2012 What Rotax say appears to be bourne out in practice. There can be build-up of deposits on the valve seats that can affect compression. This effect seems to be temporary if the running on avgas is not prolonged. The reason is put down to the water cooling of the heads and the seats and valve temps are not high enough to have the lead additives behave in the normal way. Nev Link to comment Share on other sites More sharing options...
turboplanner Posted September 22, 2012 Share Posted September 22, 2012 You'll just have to stick to the Jab Link to comment Share on other sites More sharing options...
Tecsar Posted September 22, 2012 Share Posted September 22, 2012 I and a number of other 912 drivers I know, use "Decalin Runup Fuel Additve" when no choice but to fill up with Avgas. Is available from at least one AU based on-line shop. I can't recall if Decalin has received blessing from Rotax . Link to comment Share on other sites More sharing options...
sfGnome Posted September 22, 2012 Share Posted September 22, 2012 This is what Rotax has to say about your query: Hi Greg. Could you point me to the source of your quote? It's a very useful bit of info and I just want to be able to point to its source when telling others. Thanks! Link to comment Share on other sites More sharing options...
ahlocks Posted September 22, 2012 Share Posted September 22, 2012 ... Could you point me to the source of your quote? Here's a fresh copy downloaded from the Rotax site last week Gnomester. The fuel specs are toward the end of the document. d05289.pdf d05289.pdf d05289.pdf 1 Link to comment Share on other sites More sharing options...
Wayne T Mathews Posted September 22, 2012 Share Posted September 22, 2012 Here's a fresh copy downloaded from the Rotax site last week Gnomester. The fuel specs are toward the end of the document. Straight from the horse's mouth... Way to go Ahlocks... Even talks about Decalin... 1 Link to comment Share on other sites More sharing options...
Captain Posted September 22, 2012 Author Share Posted September 22, 2012 Here's a fresh copy downloaded from the Rotax site last week Gnomester. The fuel specs are toward the end of the document. Thanks Steve, But even your attachment appears to sell a mixed message in response to my original question. Part seems to indicate that Avgas is Ok for prolonged periods if you change the oil each 10 - 12 hours, while later it seems to indicate that Avgas is only acceptable if shortish percentages (30% of the time or a bit more). Perhaps if you really HAVE to, Avgas is OK but then dose it up with the additive that they, and Tecsar, have mentioned ............. and up the oil change frequency as well. If that is the conclusion then it is manageable, I guess. Regards Geoff Link to comment Share on other sites More sharing options...
turboplanner Posted September 22, 2012 Share Posted September 22, 2012 Or plan your route so you can shandy with Mogas? Link to comment Share on other sites More sharing options...
ahlocks Posted September 23, 2012 Share Posted September 23, 2012 ... even your attachment appears to sell a mixed message in response to my original question. I chose to stick with mogas as the engine was primarily designed for it is all. As I'm a 100nm day trip woosey, I load up with enough 98PULP for the return trip plus a large fudge factor (i.e. full tanks) so really can't help with what mogas availability is like at other locations. I've always been under the impression that the Rotax 912 series will run quite happily on Avgas provided you use a suitable oil and follow a more frequent maintenance schedule. I'll try to dredge up some older fluids specs. to see when, or if, Rotax had a change of heart. P.S. Probably shouldn't do this but... (can I get double banned?! ) Big ups Yarrawonga Flight Training for stocking the new you beaut aeroshell oil at a reasonable price. VSX4 is as rare as rockinghorse piddle these days.... Link to comment Share on other sites More sharing options...
Guest Crezzi Posted September 23, 2012 Share Posted September 23, 2012 VSX4 is as rare as rockinghorse piddle these days.... VSX4 has been discontinued & replaced by AX7. I believe Shell have stated that they are essentially the same but, since Rotax haven't tested it, AX7 doesn't appear on their list of approved oils Cheers John Link to comment Share on other sites More sharing options...
crashley Posted September 23, 2012 Share Posted September 23, 2012 Lots of people only use avgas with no problems. The rotax site indicates that it is ok to use avgas you just have to change the oil and filter every 50 hours. I believe most people change oil more often anyway, I always use 98 premium at home and away i use avgas I change the filter every 50 hours and oil every 25 hours and have just changed to aeroshell plus 4 Link to comment Share on other sites More sharing options...
sfGnome Posted September 23, 2012 Share Posted September 23, 2012 Here's a fresh copy downloaded from the Rotax site last week Gnomester. The fuel specs are toward the end of the document. Thanks! Link to comment Share on other sites More sharing options...
Tecsar Posted September 23, 2012 Share Posted September 23, 2012 This from a UK based Rotax service centre...http://www.conairsports.co.uk/4-stroke fuel system.html "Can I use Avgas? Yes. But the lead in Avgas causes maintenance issues such as fouled piston rings, deposits on spark plugs, deposits in the combustion chamber and exhaust port and can sometimes cause sticking valves. The lead can also accumulate in the slipper clutch and sprag clutch, which can prevent them from functioning correctly, as well as gumming up the wastegate on 914 series engines. Please note the following for Avgas use: - Change the oil every 25 hours - use a semi synthetic oil" And this article has some indicative photos on page 5 Looking after your Rotax 912 series engine at http://www.conairsports.co.uk/downloads/912 maintenance article - inc carb bal.pdf BTW, is a great general reference used in conjunction with Rotax publications. 1 Link to comment Share on other sites More sharing options...
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