 Welcome to the FAA Production Studios and the FAA Safety Team's National Resource Center located in the Sun and Fun Complex in beautiful Lakeland, Florida. Our next presenter is the president of Lockwood Aviation, Supply and He is the only Kodiak authorized master service center in North America. He is the foremost expert on road tax engines, their care, their feeding, ADs and service information for the two and four stroke light sport aircraft engines. His topic today is the pilot's guide to road tax engine maintenance. Let's welcome Phil Lockwood. Thanks for the great introduction. Okay folks, we've got some great weather here this week, we've been fortunate with that. I'm going to give you some insight into the technical aspects of the nine series engines and some current maintenance information. I think you should pick up some good points. I want to begin with some of the unique characteristics of the nine series engines and why it's different from the typical Lycoming and Continental engines that most of us are more familiar with. First, the nine series road tax has water cooled heads and that is what enables it to get so much power out of such a small displacement. Only about 1,400 cc on a 912 s and so we run it at higher RPM and that enables us to get a lot of power out of a very compact engine. But most of the heat is in the head so with the liquid cooling we can dissipate that rapidly and efficiently. We also have a dry sump which keeps the engine compact again and it allows us to run with a very small quantity of oil, relatively small, only about 3 quarts. Because the shape of the oil canister is slim and tall we know that at a wide variety of angles we can still get to that oil in the bottom of the canister. Now one thing you should know if you're going to work on these engines is that it's important that you get the lines hooked up to the oil tank correctly. As you can see from this picture of the top of the oil can one line goes down to the bottom center of the oil tank which is your feed line which goes to the oil pump. Now in that line you will find the oil cooler in between the oil tank and the oil pump and that is the oil is actually cooled on its way to the engine. Now you can see from this picture that if you were to actually hook up the oil feed line to the return line on the tank which comes in at an angle and actually sits above the oil level which is about here on the oil tank that would be a mistake and when you started up the engine you would not get any oil pressure and if you continued to run it for more than a few seconds you could damage the engine. We have had customers do that hook it up backwards. So if you're ever in question as to which is the in and the out even though they are labeled on the tank the best thing for you to do is actually take the top of the tank off and look at it and then there's no confusion. Now one of the other tricks to making this engine very compact is the pressed crank assembly five-piece crank and because the crank parts are machine forged separately and pressed together there again we can make it very compact. You'll notice in this photo the engine does have plain oil pressurized main bearings and lower rod bearings. Now we also utilize a gearbox and the gearbox is essential to the formula that allows us to produce a lot of power out of a very compact engine. Now in the past gearboxes have gotten a bad rap in aviation engines but it's important to note that Rotax began life as a gearbox manufacturer and it's their expertise in manufacturing gearboxes that has allowed them to produce this lightweight geared engine. With the gearbox part of the package from the very beginning and not an add-on the aft part of the gearbox is actually cast into the crankcase and the engine was never envisioned any other way. The gearbox has received a number of improvements over the years but the current version is is very reliable and very durable requiring service only about every 600 hours and that service typically only costs about $100 each time around. So now you're talking about an hour service requirement. So I would I would encourage people to not be concerned about that the use of that gearbox because it works very very well and it is an essential part of making the engine do what it does. Now because we're geared we can produce max power with a propeller speed of about 2400 rpm. We reduce the the propeller by a ratio of 2.43 to 1 in the 912 s engine and so there again that makes the engine quieter allows us to turn a very large diameter propeller get a lot of static thrust for these low-speed airplanes and it's a big part of the equation. Now the newer engines also include an overload clutch. Now the overload clutch is often referred to as a slipper clutch but in fact it does not slip unless you exceed or approach the maximum torque capability of the crankshaft. So it's really there just to guard the crankshaft in the case of a prop strike. It's really more important on a tractor than on a pusher and if you have a tail dragger and you are you know susceptible to a potential prop strike that overload clutch is pretty handy and it will help protect the crankshaft. Now it does have a 30 degree set of dogs in there so actually it allows up to 30 degrees of movement between the propeller and the crankshaft when necessary. And there is friction in that zone and what that does is it allows the gearbox to absorb the torsional vibration that every engine has without damaging the gears. That's one of the tricks that Rotax came up with to make this gearbox work and the new gearboxes do go right to TBO and typically they just need that basic service where we clean them and inspect them and replace some of the spring washers but the gears and the shaft and all the major components they go right to TBO now without any trouble. In the past if you have a say a four cylinder Lycoming like an O320 or an O360 even an O200 you're producing a lot of power at very low RPM and it's direct drive so your power pulses are pretty pretty severe and that's why the propellers on the Lycoming's and Continental's that are direct drive have to be so much stronger than the propellers that we get away with on these Rotax's. Now part of the key to our light package is not just the fact that the engine is very light but the fact that we can use lightweight engines. When we're producing our power at 5,500 RPM with a four cylinder engine in effect we're turning double the RPM of a Lycoming or Continental so the power pulses are more like that of an eight cylinder engine than a four cylinder engine because they're smaller pulses and there are a lot more of them and that makes the engine very smooth. It also because of the fact that they're smaller power pulses and we have this torsional vibration dampening device in the gearbox the big power pulses don't get through to the propeller and that allows us to use very lightweight propellers that you couldn't put on a direct drive engine or you would destroy the hub. We also use an aluminum cylinder again something that in the past a lot of people would hear and say oh aluminum cylinder I don't want to touch that but they're Nicasil coated cylinders and it's actually not so much a coating it's impregnated into the cylinder wall and it is absolutely incredible I think it's one of the best parts of this engine. The aluminum Nicasil cylinders are very lightweight of course because they're aluminum and they don't have they're not steel and they don't have a steel liner but also nickel is one of the best metals that we know of today for abrasion resistance. In fact when when pump companies design large slurry pumps designed to pump abrasives like stones or sand in water they typically will build them out of nickel or line them with nickel because of its resistance to abrasion and that nickel silicon alloy that is on that cylinder wall makes these things wear like well I can't say wear like iron because it's really way better than iron. In fact we've had engines come into our shop now with over 2,000 hours like 22 I think the highest one was 2,200 hours running at 5,500 rpm cruise and we measure the wear on the cylinders and I think that one was about a thousandth of an inch wear total. In fact the tolerances are so tight that on a new nine series engine the tolerance out of the factory between the piston and the cylinder wall is 0 to 8 tenths of one thousandth of an inch total clearance. There is no break in there is no burning of oil everything is so precisely machined that you can pretty much figure on about a quarter of a quart being consumed in a hundred hours and yes we can go a hundred hours between oil change intervals if you're using unleaded fuel. Now just to emphasize how tight that is I've taken brand new pistons and put them pushed them in the cylinder without the rings and I can turn it upside down and it doesn't fall out. I mean it just it's you really look at it and you go this can't work but it does. Now the other thing is because they're nicosil cylinders we don't have to worry about corrosion because they won't rust and we don't have the shock cooling issues that you have with the steel cylinder and an aluminum piston because the aluminum piston and the aluminum cylinder will expand and contract together and so that's why we can hold those very tight tolerances. Now you might think that why is it that only Rotax has this technology and some people are skeptical when they hear about me talking about this nicosil cylinder on these four stroke engines and they think well you know if it's so great then why aren't other people using it well they actually are. Most of the new BMW automotive engines use nicosil cylinders. Porsche has been using it on their engines for many years and so it's not really something that only Rotax uses. It is an expensive process and therefore you typically only see it in the higher-end automotive industry but for an aircraft application it is really good. Now another feature of these engines is an electronic ignition system. We have a completely redundant dual electronic ignition system which essentially has no moving parts. The flywheel is the only moving part and of course you have to have a flywheel anyway so the coils that you see in this slide are actually fixed to the block and in the flywheel you have magnets that circulate around these coils and excite them and that's where you get your spark. Now this ignition system differs from the electronic ignition system that you typically see in your car in that it is a AC ignition system. Automotive ignition systems run on DC off the battery and that means that if your alternator should fail in your car and I've had this happen to me and you will continue to run off the battery until the battery dies. Now if you're in the winter time or in the summer where you're running your AC fan it won't take you long to draw that battery down once you have lost your alternator and once your voltage drops down somewhere in the 11 volt range your engine will stop running. That's really not acceptable on an aircraft so what Rotax did was they made this AC ignition system and you can see here that two of these coils with the red arrow pointing at them are the coils 1H that power the ignition systems. Now what that means though is that the actual energy for the spark is being generated as the engine is running so when you're starting the engine it is critical that you get about 240 rpm to have enough rotational speed to create enough spark to get the engine to start so that is something you have to understand it's the bad that comes with the good. We do need a strong battery and good connections to make sure the engine cranks over fast enough and it also makes the engine not really a candidate for prop starting because we have to crank it over pretty fast. The plus side of that is it's a simple system there's really nothing there's not much to go wrong and it's unlikely that anyone would ever start an engine by accident while turning the propeller over because you have to turn it over pretty fast so that's a nice safety feature. Now those other coils that you see on that stator are to charge the battery and so what we have again instead of having an external alternator where you have belts to worry about and mounting brackets to worry about breaking and vibration our generating system is an AC system that again has no moving parts it's bolted right to the right to the block and it has an external solid state device which rectifies that AC current to 14 volt DC and that gives you a maximum of 18 amps which is enough for most of the modern lightsboard airplanes even with strobes and lining lights and a couple of radios and an EFIS most of them we can get by with that. Rotax does offer an external 40 amp alternator if you want to carry a lit banner behind you. Automotive spark plugs is another nice feature if you guys have worked or had a light combing or continental you know how expensive those spark plugs can be those special aviation spark plugs we actually started with aviation spark plugs and they were like 20 bucks each and Rotax quickly realized that they could use an automotive style spark plug and that they could still certify the engine with that so that's what they did and so the spark plugs are cheap and we change them every 100 hours on the 912 s. There you see the the 70 DCP R70 is for the 80 horsepower 912 the 8E is used in the 100 horsepower 912 s and then the Denso U9 is the as the correct spark plug for the 914 turbo. Now we utilize constant depression carburetors in this engine they work very well they have the ability to control the mixture they actually do lean the engine as you climb and so there's no need for a mixture control there isn't a mixture control so all these engines are a single knob set up you just have your throttle control and you're throttling the engine with the butterfly that you see in that left screen there there is a slide that you can see from the intake side of the carburetor on the right picture and that slide goes up and down pneumatically via a chamber there's a airtight chamber in the top of the carburetor which allows that slide to go up and down via vacuum and what it does is it senses the pressure and it moves it up and down and brings that needle up and down inside that carburetor and that's what changes your mixture automatically as the density decreases pretty pretty nifty carburetors do need service I mean they need to be maintained and taken care of and if you do a reasonable job of taking care of them and setting up they work very well two carburetors allow us to get a lot of power out of that little engine now if you have questions I'd ask you to hold them to the end and I will leave some time at the end of this presentation to answer questions there'll be somebody coming around with the microphone so if you think of a question try to remember it and I'll be happy to answer it towards the end of the presentation on this page from the Rotax website you can see the small size of this engine here exactly 1352 cc's of displacement for the 912 s quite remarkable only 82.6 cubic inches in displacement and that is again part of the reason that engine is so small and so light and what is remarkable when you look at small automotive engines and there really aren't that many in this country that are actually that small 1.4 liters those engines typically run at 15 20% power output I mean that's all they put out if you open up your car it's typically only for a short time to sprint up to 60 miles per hour then you got to back off on the throttle you're going to be exceeding the speed limit and these engines have to be built to run literally wide open we have a lot of customers to prop them so that they will turn only 5500 at full throttle and and they run them wide open except when they're on approach to landing and when they're on the ground the rest of the time they're right to the boards and they take it they'll go 1500 hours like that provided you keep the oil temperature cylinder head temperature coolant temperatures in the green and maintain the engine properly now also the engine comes in two versions the 912 s is the far 33 certified engine so the engine has achieved full certification and if you buy that version it can be placed in standard category aircraft and used for any type of commercial application what rotex did was they they take the cost that was involved in getting full certification and in keeping the paperwork trail that's required for those certified engines and they only make the people that need the additional advantages that you can get from a fully certified engine to pay for those so it's about $5,000 more if you want a fully certificated engine if you're going to use the ASCM compliant version which is what most of the special light sport aircraft use rotex does ask that you fly only vfr day and night and not fly IFR with that with that particular type of engine but you save quite a bit of money and it is essentially the same engine if you want to fly in a they're again a standard category airplane where you can use it for unlimited commercial applications or if you want to fly IFR then they ask that you put the far 33 version which is the 912 s the 912 us is the ASTM compliant version now mechanics who wish to perform service and maintenance on the rotex aircraft engines if they're installed on an s lsa must meet the training requirements specified by rotex and utilize the correct tools and fixtures as outlined in the applicable rotex maintenance manuals this is very important not just to meet the letter of the regulation because most of the airframe manufacturers today if not all require you to follow the rotex maintenance procedures and guidelines so to be legal on a special light sport aircraft and to be safe you need to have rotex specific training now on the airframe side only mechanics that have an lsrm rating which is a light sport repairman with a maintenance rating or an amp certificate and you can also actually work on a special light sport if you are a repair at lisa f8 license repair station can work on the special light sport aircraft perform annual condition inspections and you'll find in the manuals they will outline who can do what and what what is required I'm going to get into some details here on that now when you're working on a special light sport aircraft the maintenance manual will tell you what the requirements are for performing that maintenance if that particular maintenance item that you want to perform is not covered in the maintenance manual then you have to go to the airframe manufacturer and get a procedure and approval to perform that maintenance this is an example of a request for an avionics installation approval that flight design uses you can't take a special light sport airplane to gulf coast avionics and tell them you want a jam up panel you just want them to put put in all this great avionics which you could do in assessor 172 you could go to gulf coast and tell them what you want and they can do it and they can do all the paperwork and out the door and you're set can't do that with a special light sport the actual airframe manufacturer has to approve the installation of of all the avionics so if you want something different than what's on your approved list you have to get approval from the manufacturer and you need a procedure to make sure that it's being installed properly on this section of the ct manual again you can see they're going over procedures for working on the landing gear section at the bottom of this page here they say minimum level of certification required repairman light sport aircraft maintenance or higher grade certificate task specific can be completed by a responsible individual who's received flight design airplane operational training okay so flight design actually has their own maintenance training that they make mechanics go through there is a little catch though in this where it says a light sport repairman certificate maintenance or higher the f8 doesn't like that wording and they're actually saying that if it says that there is no higher that you actually can only be a light sport repairman maintenance rated and perform the maintenance on this airplane that's laid out in this part of the manual if you're an amp you can't do it if you're an amp with an eye you can't do it if you're in a repair station you can't do it legally even though we know they meant that when they said or higher so as a result these companies are now changing their manuals and including that specific wording I think flight design they they're putting on a bulletin that says that that's what they meant to make sure everybody who has been working on them is legal and they're changing all their manuals so just so you know that that's a little catch that's coming and you need to check the manuals of the airplanes you're working on to make sure that they include if you're an amp you as an amp so that you're actually legal now it is important that you keep good records accurate records on all the maintenance engine logs and air frame logs must be separate because the engine may be removed at some point and that log will go with the engine and you'll get a new log with the new engine now types of training that are available from Rotax they have three courses that are that are very well very good very well laid out and they were actually specified by Rotax what would be sorry which would be what would be in each one of them doing the hand thing here whacking the mic service is the first level to two-day course and it gives the student the necessary knowledge required to perform routine maintenance up to a hundred hour inspection it's a it's a it's basically 16 hours of training and it it's very good everyone I know that's gone through it has really enjoyed the course for owners it's a great great intro to Rotax I mean I'm gonna give you some great information here in 45 minutes or so just imagine how much information we can give you in two full days and they pack two full days there's a lot of hands-on and we actually have our own school our facility with it with a dedicated instructor who is back in the back of the room Dean Vogel who can who does a really good job of going through all that information he'll be available after this presentation if you have any questions the next level is maintenance level and maintenance gives the student the necessary knowledge required to exchange components and perform advanced troubleshooting that's a two-day module of course the service module is required before you go through the maintenance module between those two courses four days of training a mechanic can probably get 90% of the information he's ever gonna need to work on Rotax engines so that's a very time and cost-effective package with those two courses now if you want to actually overhaul components then you need to go through the next step which would be the heavy maintenance because basically at the maintenance level what you're gonna be doing is you're gonna be removing components you can send them off to a repair station like Lockwood have them overhauled and then returned and then you can reinstall them on the air for on the engine and then return it to service and in fact unless you're doing those overhauls every day of those components cylinder heads gearbox work it's probably better to just let a center that does it every day do it because you'll get rusty I mean you need to be doing it on a regular basis to stay current and it requires quite a few special tools and we do have our next course scheduled June 15th and 16th there is a service course at our facility in Sebring and on the 17th and 18th we follow up with a maintenance course so anybody who's interested in that can head over to our booth or talk to Dean and they can get you signed up on those we can only accept a maximum that's 16 Dean 16 yeah 16 and 12 in those courses and they do tend to fill up fairly quickly. Now Rotax has gone through and changed all their manuals for the nine series in the past couple of years spent a lot of time on it and the results are quite good the manuals are available online I'm going to show you how you can get those manuals and download them as a PDF file at no cost. If you go to the Rotax website on the bottom of this page here you'll see www.rotax-aircraft-engines.com that is one place where you can get all the technical information that's available for free. If you go to their website you're going to see a page that looks just like this if you look at those tabs across the top and you actually go over here and you click on documentation then it will pull up a page like this and you'll have pull-down menu bars of course you're going to typically pick English 912 ULS and then in this case I have clicked on maintenance manual and then this page will come up and you'll see the manuals that are available and on the right these PDF files if you click on those it'll open the file and then you can actually print it on your on your computer. There's another site that's very handy for Rotax information it's called the Rhone site which stands for Rotax owner association and that is available at rotax-owner.com. Now these fellows up in British Columbia have crafted a number of videos training videos which help you go through different procedures required to maintain these engines. They're very good in this case if you were to click on support and roll down to expanded video instructions you're going to find some great videos and there again you can download those for free. Now before we move on I want to go over just a few carburetor tips carburetors on the Rotax aircraft engines the 9 series they should be synchronized using separate vacuum gauges and rechecked every hundred hours. This should be done by someone who knows how to do it it is important to make sure the engine idle smoothly and the reason is you essentially got two separate engines really that are sharing the same crankshaft you've got two cylinders on one side fed by one carburetor two cylinders on the other side fed by the other carburetor very lightweight crankshaft flywheel and it's important that those two carburetors are set at the same vacuum they're throttled with a butterfly and if one is more advanced than the other then you're gonna have a strong power pulse and a weak power pulse strong power pulse and a weak power pulse and what that causes is it's known as torsional vibration if the engine is set up properly the carburetors are balanced it will idle like a sewing machine it'll run like a sewing machine and that's the way it should be it'll also affect starting you won't notice it very much at high power settings because things will even out at high power settings it's at the lower power settings that the carb sink and setting up the idle are so critical minimum idle speed is 1400 rpm the engine has a very high performance camshaft and it is a high compression engine so it doesn't want to idle below 1400 rpm I realize that at 1600 rpm which is a typical idle for this engine you've got only 658 propeller rpm because of the gear reduction drive so propellers still turning quite slowly you'll pick up about 200 rpm from the time you start the engine till the time it warms up so if you set your idle at 1600 rpm then it'll be unlikely I'll go below 1400 when it's cold so that's a good range we don't some heavy propeller designs require an idle of up to 1800 rpm to keep everything smooth but we don't like to go over 1800 because at that point the choke system the original system won't work because the butterfly won't actually close enough to allow the the original circuit to work now that's another tip that I can give you when you're starting these engines in cold weather if you're going to use what we call the choke it's actually an enriching circuit that circuit what it does is it opens up a valve which allows extra fuel to flow from the float chamber up into the venturi but in order to make that work the butterfly that throttles the engine has to be closed almost all the way so what does that mean that means if you're using what we call the choke circuit you better have the throttle all the way back at idle if you crack the throttle you will decrease the effectiveness of the choke dramatically so in cold weather pull the throttle all the way back pull your enriching circuit on or your choke on all the way start the engine as soon as it lights you can advance the throttle then and still get some effectiveness out of the choke it really has almost no effectiveness though at at high power settings now on some of the airplanes coming over from Europe and as we know a lot of the special light sports today are coming in from Europe they use different antifreeze over there so it's important to to understand the fact that if you see something like this in the manual on the firewall it says 80% antifreeze 20% water you can't do that with the American antifreeze now US antifreeze will work in these airplanes but it's it's it's mixed at a different density so with our antifreeze we typically use a product called Dexcool which is made by a number of different companies 50-50 with distilled water is the way we mix it and certainly you can't mix it any richer than 66% coolant okay if you do some of the particles in that coolant are going to drop out and they're going to form crystals inside the engine and actually impede the cooling so 50-50 is what we like to see if you see that on a European style airplane you know you don't want to do that with our coolant usually after about 200 hours or two years we'll drop the European coolant out and replace it with Dexcool and then from that point on you can you can buy it locally we do stock some of the European coolant for people who need to top off their engines while they're new until they switch now we get a lot of questions about oil because you you don't want to use typical aircraft oil in these engines as I discussed earlier in the presentation they're really built more like automotive engines automotive or motorcycle type engines with their with their tight tolerances and the metallurgy that's used inside the engine so what we like to use is an automotive style engine with a gearbox additive and that would be a motorcycle oil that's the way most motorcycle oils are used today because we use our engine oil to lubricate our gearbox just like most modern motorcycles do today in this case you can see this mechanic is filling up the oil tank with the new aeroshell product now we have three types of oil that we typically use or get questions about one would be a full synthetic and this is one of the best examples of that mobile one that is an ideal oil if you're going to go with just unleaded fuel now the base stock in mobile one and most of these full synthetic oils they do not react well with tetral ethyl lead if you use 100 ll it will tend to cause a lead paste within the engine which is like a waxy substance and it literally will plug up the oil passageways and eventually could cause the engine to fail due to oil starvation so we like to use the mobile one in applications where the customer is only using auto gas unleaded auto gas you could get a little bit of gas in there but you don't want to be using too much then we have mineral based oils which are less expensive this is an example of a pens oil motorcycle oil which is available in 2050 and 1040 weights and those oils tend to be maxed out at 50 hour oil change intervals you can't go to the 100 hour oil change intervals and they typically will work with different types of fuel and then you have the new shell product which appears to be a very good product it actually has the rotex name on the bottle it was developed in cooperation with rotex it's a 10W 40 weight so it will work in any temperature range cold or hot and it was it is a semi synthetic so it has many of the properties of a synthetic oil but using shells experience with Avgas many years of experience with Avgas they were able to blend a semi synthetic which will work with Avgas now I'm talking about the different fuels here I just want to mention oil change intervals and how they can be affected by the the type of fuel that you are using if you want to go with 100 hour oil change intervals it appears that you can do that with this shell product as well as with the full synthetic products like mobile one but if you want to use Avgas and you're using it say up to 30% of the time that's going to whack you back to no more than 50 hours between oil changer intervals regardless of the type of oil you're using if you're using Avgas more than that primarily Avgas then we recommend oil changes every 25 hours you got to realize we only have a little over three quarts of oil so with that small amount of oil we'll get loaded up with lead fairly quickly if you're using Avgas so you can use Avgas but there again you should move to the more frequent oil change intervals we get a lot of questions about the oil filters on these engines because it is an automotive type filter however it is it is a filter that is specially made for the Rotax application and one of the differences between this and an automotive filter that you might find at your local auto parts store and we have had guys go to the auto parts stores and find filters that they can get to fit on this engine but the bypass ratio bypass valve is set at a higher pressure on these filters the reason for that is in a car you can stand to have a lower bypass pressure because it's unlikely that you would start your car up and warm it up for a very short period of time and then go to full power and leave it there not many people do that in their car you know started up and you know get it out of the driveway warm it up a little bit and then just firewall it and head to work what that would do is it would cause your filter to go in bypass now with the Rotax filter the bypass pressure is high enough and the filtering material is such that as long as your oil temperature is above 120 degrees Fahrenheit you should not be bypassing the filter element even at full power and that's the reason that one of the reasons Rotax requires 120 degree Fahrenheit temperature before you go to full power on the oil now you'll notice that there's a bit of torque seal on this filter it's a good idea once you've finished tightening the filter to put the torque seal on there Rotax lists a procedure to tighten that filter and what they say is that the filter should be you put clean the the contact surface on the engine and then put a coat of fresh oil on the gasket on the filter screw it on and then when you get solid contact which is about an eighth of an eighth of a turn beyond touching solid contact you go 270 degrees and that's that's where they want to see that filter what we usually do is after we've done an initial run run the engine for a few minutes to check for leaks after an oil change it's always a good idea before you cow your engine up that you do that you know run it make sure nothing's leaking then go back to the filter and and try and screw it off and if it you know if it wants to come off then it needs to be a little tighter people who live up north often and let their airframe sit for the winter one of the one of the biggest concerns there is the fuel going bad if you use auto gas auto gas is only going to last a month or so in the carburetor bowls before it starts to go sour on you so we recommend that you either fill up with Avgas before you make your last flight of the season which is very stable and tends to to sit in storage well for extended period of time or if you're using auto gas put a fuel stabilizer in it like this pens oil product there's also a product available at Walmart called stable which works and those things those products really do a great job they will keep the oil or the fuel fresh throughout the winter and you won't have gummed up carburetors come spring now rotex does have different octane ratings for the different engines one of the advantages of the 80 horsepower version of the engine is that it will run on 87 octane fuel so if you're flying overseas if you're flying and you want to use mo gas at an airport if you have a 80 horsepower engine you can fill up and remember when you go to airports that have mo gas it's often only 87 octane now if you have a 912 s that requires 91 octane or higher so premium grade the same with the 914 turbo so even when you see an airport listed that has mo gas you usually still have to use the Avgas because the mo gas is usually only 87 octane now that's changing a lot of airports that have mo gas now are going to the higher octane because they're realizing that even though the STC's for a lot of these airplanes only need 87 octane the rotexes need 91 or better so what we're seeing is at our airport they're going to put in auto gas I know within the next six months and they're going to they're going to run premium out there now if you have a two stroke the 447 the 503 the 582 will all run on 87 octane fuel the 618 is the only one that needs premium now we do have a tester available now that will allow you to test for ethanol content and ethanol is certainly one of the points where we do get a lot of questions with this tester you can fill it up to the zero mark that you see right there and then add fuel up to this mark right here shake it up and let it sit for a little bit and if the fuel has alcohol in it what will happen is the alcohol will fall out and attach itself to the water because there's so much water relative to the amount of gasoline in this tube and this level will it rise and if it rises to here that's 5% ethanol rises to here that's 10% 15 20 so it's pretty handy and it's pretty easy to tell how much and if you have ethanol in that gasoline now rotex over the years has officially approved gasoline with up to 5% ethanol they have recently moved to approve fuel up to 10% ethanol as long as your fuel tanks can handle it the engine itself can handle it they also I'm going to at the end of the presentation I'll just tell you about a few changes to the fuel system that should be made if you are going to run 10% ethanol ethanol does affect fuel lines although the engine major components in the carburetor are viton the engine doesn't seem to mind the 10% at all fuel lines and fuel fittings fuel tanks can be affected by it this is an example of common fuel line used in ultra light and light support airplanes you can see what it looked like new you can see what it looked like after a couple of years of use so you have to be careful make sure those lines are high-grade or that they're changed often there's a new product available after market but it appears to have the consent of rotex it's called a soft start module and it's a pretty pretty nifty little piece of electronic equipment we have one in our booth over in building D if you want to take a look at it what it does is it it retards the ignition timing on the engine from 26 degrees before top dead center back to four degrees when you hit the starter and it keeps it there until two seconds after you release the starter and what that does is it avoids kickback that can occur when you're using just the standard modules the standard modules actually retard the the they start out with the with the ignition timing retarded but then as soon as they see about 800 rpm they advance it and every now and then when you're starting the engine will jump to 800 rpm and then come back and keep cranking at that point the ignition timing has been advanced and you can get a backfire or kickback which is hard on the gearbox this was only installed on one of the ignition modules and then you start on that what we call magneto and then as soon as you started you go back to both now here's that drawing of the fuel system that I was going to talk about here and you can see that we come from the fuel tank this is the fuel tank through a filter and buy an electric fuel pump which should have a bypass around it in case it gets plugged up and into the mechanical pump which is actually mounted on the gearbox itself and then we go to this distribution block which is mounted between the carburetors on the engine this is the part that I wanted to mention at this point here there should be a return line and that is essential if you're going to use fuel with alcohol in it what that does is it ensures that there's always a stream of fuel circulating in your engine compartment and that if any air or air vapor pockets should develop that will allow them to be returned to the fuel tank so you won't get any vapor lock you won't suffer from vapor lock but on some of the airplanes Technum is one example that return fuel line goes back to the tank and it only goes back to one tank or the other if you have wing tanks right and left you need to know which tank it's returning to and you want to make sure that if you start out your flight with full fuel that you start it with that tank now at this point I'd like to take any questions that we might have got a mic right here okay well I wanted to say that the Roan dialogue that they have there I thought that was excellent with the videos and I wanted to know how many watts it the engine puts out at what power level that the the output of the the generator for charging well I can't tell you what the output is at any given power level I think they have a chart in the installation manual which will give you that information I can tell you what you really need to know is that you can only count on about 14 amps of power for your max continuous load and we'll put out 18 amps at full power but what we found is in reality in practice if your your if you add up all the loads that you have and it's 14 amps or less everything works just fine if you try and draw more from that system on a continual basis you'll overheat the coils next question over here yes on a little oil pressure there's been several discussions on the internet about putting just changing the spring and the ball your thoughts on it well if you're running about 30 pounds well okay 30 pounds would be would be safe yeah but it's less than normal okay so if I if I have an engine that is running less than what I consider be normal say 40 45 to 55 would be typical for a warm engine first thing I would do is I would check for an instrument error because it's very unusual to see one of these engines actually run low oil pressure normally it's the sender that the oil pressure sender which in this picture right here would be located right here next to the oil pump okay I would I would what we do in our shop is we have a calibrated mechanical gauge that we have to send out for calibration once a year we hook that up to the oil system and we see exactly what the oil pressure really is if it's if it is equal to what your gauge is saying then we would pull the spring and either add a shim or put a different spring in there often just replacing the spring is enough to increase the oil pressure but in most cases that is not the problem the problem is an indication error and it's usually the sender so we'll replace the sender and the pressure comes up to where it should be and and the senders tend to fail in that manner the pressure indication drops okay so that's usually what happens but yes you can increase the pressure by changing the spring or adding a shim but don't do it until you make sure that your indication is correct another question right back here the explanation for not using a mixture control was very good and I understand that what's the reason for not using carburetor heat on this particular engine and carburetion system okay it's really up to the airframe manufacturer or in the plate in the case of experimental aircraft the owner builder of the airplane to decide whether they want carburetor heat or not rotex doesn't say that you don't need carburetor heat in fact these engines tend in most installations to be less prone to icing than some like homies and Continental's but it differs with the installation and they can ice under certain conditions I think that the installations that seem to be most prone to icing are open uncaled pusher installations and and typically where we see ice would be in a temperature range 40 to 50 degrees very humid almost misting conditions you can ice the engine particularly at low power settings now the installations that tend to be less prone to icing would be culled installations where the engine breathes warm air from within the cow okay and the carburetors tend to be warmer they're sitting right on top of the exhaust pipes and and so you don't get some of those installations you never hear of icing okay but there are several means of of installing carb carb heat one is off the muffler and the other is a water jacket which which attaches to the carburetor and actually heats the carburetor body okay and and those are available the one that amounts to the carburetor body is relatively easy to install and it can be left on all the time and offers almost no power loss so pretty slick set up if you you basically have to do the research and find out if your installation is one of those that's prone to it and if you're going to be flying in conditions that could cause it you welcome right here and then we'll move over to you sir I'm building an amateur experimental aircraft I'm going to be putting a 912 UL at ULS engine in it and what I'd like to know is if I do the service and or maintenance training that you offer will that qualify me to do the balancing of the carburetors which you indicated was was critical of the proper function balancing would come in the maintenance service okay cool good thing we got Dean here yeah so you would get that in that first two days and they actually will will run an engine and you'll see it done and you'll get to participate in it so it's really it's good training in that respect once you see it done you see how what's involved most people can do it themselves over here okay over here thank you two quick questions what about NKG I think it's called for coolant and I'm running a mobile motorcycle oil now if I want to switch to aero shell do I need to completely drain the engine or just change the three quarts in like you would normally do okay first on the Evans coolant you some people do use Evans coolant road tax at this point leaves it up to the airframe manufacturer to recommend to you which one you should use it's really based on that the temperatures that your engine operates at actually the standard coolant let's say dex cool mix 5050 with distilled water does a better job of cooling the engine than the Evans typically when you switch over to Evans the engine will run about 20 degrees hotter the reason that that some people want to run Evans or some installations need to run Evans is because it doesn't boil until it hits about 340 degrees whereas conventional coolant with the pressure cap that we use will boil at about 250 degrees 248 degrees our cylinder head temp max on the 912 s is 275 that's based on detonation if you go over 275 degrees cylinder head temp you can detonate burn a hole in the piston okay the cylinder heads themselves are good for about 300 degrees before if you exceed 300 you're going to damage the cylinder head on the low compression 80 horsepower engine you can run up to 300 degrees okay so if you're running like 260 degrees cylinder head temp with a with an 80 horsepower engine you're going to be could boil the coolant and you're going to air pockets and you can blow the coolant out of the engine if you switch to Evans you'll bump up to 280 but in that case you're still with you're still under the 300 max so you're still safe and you're not going to boil the coolant so that's where the Evans comes in for installations that are running right up there near that 248 degree maximum coolant temperature it gives them a bunch of headroom and on those hot running installations when you land on a hot day and the engines heat soaked and you know you're taxing downwind you're not getting much air through the engine a lot of them will want to boil the coolant then and that Evans will stop that so you got to realize it's not the engine that makes it run hot I mean I have installations that run 120 degrees they barely come off the peg at any time on the aircams like that it's always running too cold and then we see other installations that run 200 degrees on a hot day 210 they're perfect and then you see other installations that run up near the limit 250 260 even 270 and and that's where that Evans comes in does that answer your question you know on the oil if you're going to switch from a conventional motorcycle oil to the aeroshell you do not have to do anything special you drain the canister do a normal oil change and in fact Rotax does not want you to drain the oil cooler or the lines okay they want you to leave that oil in there because they don't want to get air ingested into the lifters any more questions right here hang on just a second sir let me get get the mic there you go is TCP any help to you when you have to use that gas yes we have found that TCP is helpful it does help mitigate the negative effects of tetralethyl lead in avgas especially if you're going to run lower power settings it helps take the lead and it just burns it right out of the engine without building up lead on the valves so it is it is it does does work right here yeah I've heard about the procedure for some people refer to it burping the engine after an oil changer I don't know if that's after a normal oil change or if after a complete drain can you define when you need to do that and what that procedure involves sure absolutely the burping the the engine comes from the fact that we're a dry sump engine and our oil that accumulates in the bottom of the crankcase as engines lubricated and cooled by the oil it all flows down into the bottom of the crankcase and there's a fitting there with a line that goes back to the oil tank so blow by from the engine pressurizes the crankcase and pushes that oil back to the oil canister okay so this new these new oils today do a really good job of coating and sticking to the engine so when you shut off your engine there's going to be a lot of oil left inside the engine and that oil is going to eventually accumulate down in the bottom of the case okay if the oil canister is mounted high that that problem can be compounded by the fact that the oil can siphon back to the oil pump if your oil tank is mounted high and and accumulate in the bottom of the case the burping the primary thing with a burping for most end users is when you check your oil you pull that dipstick out if it's in the flat range you just go fly you don't have to burp the engine you know you have enough oil you're fine if you pull the dipstick and it's below the acceptable range that flat section on the dipstick then you may need to add oil okay we know that's unlikely with this engine because they don't use much but still we can't just assume that it has enough oil in it so that's when we burp it that point we'd leave the top off the canister pull the prop through in the direction of normal rotation and the easiest way to do that is pull it up till you get a power stroke top dead center hold it there and then go to the next because we're looking for maximum blow by right so we don't just want to pull the engine through we just want to pull it and hold it right at top dead center just before it pops over we're