There is an industry stigma that Rotax 2 stroke engines 503/582 are not as reliable as the 4 stroke 912 and they die quickly and for unknown reasons. The truth is that 2 strokes do not die, THEY ARE MURDERED.
Here are some simple tips to help you run your 2 stroke as reliably as possible.
MIX OIL AT THE PROPER RATIO
First and most important – use the manufacturer RECOMMENDED mixing ratio. Most Rotax 2 stroke engine failures are simply from lack of lubrication. I have heard so many stories about how people are so proud to have mixed at 100 to 1 instead of the required 50 to 1 because someone said it was OK. At 100 to 1 the engine runs great with less smoke but with half the engine manufacturer lubrication it will fail. That would be like running the four stroke with half the lubrication. The oil injection system is a great way to provide the proper mixture the engine without having to premix at 50 to 1. It provides the proper mixture at full throttle 50 to 1, and a higher mixing ratio progressively to idle. Overall, oil injection is great because it will produce less carbon deposits in the engine allowing it to go further without decarboning.
USE GOOD OIL
Use a good well know reliable oil. Many engine failures are from some new oil mixture, some magic new oil or someone trying to save money on cheap oil. I recommend three types of oil. The most reliable over history is the Pennzoil - 2-cycle Air-Cooled Engine Oil. This has been tested and is proven to be the best dinosaur oil. This is the preferred oil if you are in a humid area and/or go for longer periods without running your engine. Pennzoil - 2-cycle Air-Cooled Engine Oil produces the least amount of carbon deposits (for dinosaur oil) and keeps oil on internal components with so they do not corrode when sitting in a humid environment for longer periods without being run.
The new Aero Shell Sport PLUS 2 has been recently developed specifically for Rotax 2 stroke engines and has been tested and provides the same protection as the Penzoil. This is another recommended viable option.
Another option is Amsoil 2 stroke synthetic oil for low humidity environments where you run the engine more and do not let it sit around for long periods. The advantage is that it produces less carbon and burns cleaner. The disadvantage is that the synthetic oil which does not coat the internal components of the engine as well over time allowing internal corrosion which can lead to engine failure.
Using fresh fuel from a major manufacturer will help an engine run better and avoid detonation and preignition which will cause extra wear and tear and eventual engine failure. Higher octane fuels are generally more refined and higher quality so pay the extra per gallon for a quality brand high octane fuel. Fuel degrades octane over time so fresh fuel is better. I usually drain my fuel if it is more than 3 weeks and put in fresh fuel.
MANAGE ENGINE TEMPERATURES
Warm the engine up. If you go to takeoff power with a cold engine, it creates extra wear and tear and will fail than or create damage and fail later. Even when the CHT and water temperature reach the proper operating temperature the crank and gearbox may not be properly heated for takeoff power . Besides getting up to operating temperature, I run my two strokes for at least 6 minutes in the summer and 8 minutes in the winter to warm the complete engine before takeoff power. If you do a long descent the engine cools to below operating temperature. During a long descent bring the RPM UP to somewhere mid RPM 400/4500 to warm it up before applying full power. If the engine is cold and you go right to full power, the aluminum piston will heat up, expand and will either scratch the inside of the cylinder which will lead to eventual engine failure. Many times the engine will seize/stop as the piston gets big enough where it cannot move. This is the classic problem where the engine fails, the engine piston and cylinder walls equalize, and then the engine starts and runs fine. This “Cold Seizure” is the big mystery of why the engine stopped but runs fine now. It runs fine but has been damaged because the inside of the cylinder walls and piston are scratched. Simply managing your engine temperature will avoid this problem. The 582 Blue head does have 2 thermostats to minimize this situation but proper temperature management will avoid this problem.
Historically, rebuilt engines have a much higher probability of failure than a new factory spec engine. I do not trust a rebuilt engine. A new block (crankcase, pistons, head, electric/mags, oil injection) only cost about $5000 for a 582 so simply replace the block when it is time. In my opinion, a rebuilt engine is unreliable and worthless. I have only heard bad things about rebuilt engines. When is it time for a new engine? Rotax recommends and requires for S-LSA a rebuild/new engine at 300 hours. Industry experts say with proper operation as discussed above they can go about twice 600 hours to 800 hours which plenty of 505/582’s go. I replaced my 503 at 750 hours. I premixed Pennzoil at 50 to 1, ran premium fuel, managed the temperature and never had a blip, hesitation or bad moment. At 750 hours, it ran great, compression was good and there was no difference when I put the new engine on. Two strokes run great unless they are murdered.USE GOOD FUEL
John Williams set out June 6 in his Revo, flying from Williamsburg, VA towards New Braunsfel, TX. A family friend Kenzie, is along for the first part leg of this trip as they fight their way through the awful weather that has been pummeling the East and Southeastern parts of the US. Here is a link to John's blog about this walk - (fly) - about. Follow John as This Most Excellent Adventure unfolds.
I also left June 6 from Lodi, CA to meet John in New Braunsfel. The biggest challenge so far has just been getting out the hangar door (Well that and downing a shot like a Real Cowboy! I'll tell you about that in a moment.).
Two weeks before leaving,I damaged my prop on a trip around the Eastern Sierra Nevada Mountains. Luckily it's a Warp Drive Prop and I was able to send it by Two Day Air to Daryl at Warp Drive in Iowa, where he repaired it and sent it back by Two Day Air also with a couple days to spare. But then things got strange.
An ordinary muscle spasm in my back kept growing and growing and getting more and more painful until I was laying on the floor of my bathroom throwing up from the pain. Is this what a heart attack feels like? I threw up about 30 times from the pain and at that point was finally able to be driven to the ER. My heart is great and all I needed was DRUGS...NARCOTICS. OMG it felt so good to not hurt --- lucky I don't have an addictive personality.
So a few massages, a transition to Advil and and a couple days to shake this all off and I'll be ready to go...right? Well, I thought so anyway. Then my trike radio AND my interface blew up, fried, shot...don't ask me how, we don't have the time here. So work is a mess but manageable, I'm out of the ER and off narcotics and beginning to enjoy Advil, I re-installed the prop (don't worry, not while on the narcotics) and now I need to PACK AND INSTALL A NEW RADIO AND INTERFACE IN ONE AFTERNOON?
There was only one thing to do. Rig up my trusty Icom A6 and hope it worked. Got to bed by 11 PM and the first radio test was as I flew by Modesto tower the next morning. "Uh, Modesto Tower, this is Experimental 912QR, radio check please?". "Loud and clear!", he responded. Yahoo! The trip was on!
The WX was clear skies and hot as I headed south down the California San Joaquin Valley and crossed the Tehachapi Mountains at 11,500' due to the strong headwinds and as anyone who has flown in desert areas knows, the ferocious thermals. Most of the flying was at 9,500' across the Mojave Desert but it was getting pretty bouncy even up there and I need to come down for fuel at Blythe, CA. Wow, what a ride. There was a Citation doing touch and goes as I descended and I just hung on for dear life. Maybe the kind hearted Citation pilot heard the girl like squeal of fear in my voice but he extended his downwind by a lot to allow me to cut a few corners and come in for a smooth landing. I'm not sure how hot it was when I landed but a couple hours later I was told it was 111 degrees!
Well the next day I was fully back into the old routine. Early departure, a fuel stop at Manama AP just west of Tucson, AZ and the final destination at Dona Ana AP just west of El Paso, TX. Also there seems to be a new routine of the roller coaster ride down through the thermals, squeals over the radio and somehow I made it again. It seemed cooler here. Only 101 degrees.
This called for a celebration! Off to the Texas Roadhouse for dinner. What a great place! Hank Williams and Waylon Jennings blasting over the sound system, eat your peanuts and throw the shells on the floor and then yell HELL-YEAH!!! And then what happens next? Well HELL-YEAH comes right back at you!
Well I know you're probably wondering at this point about that thing I mentioned at the very beginning? You know about downing a shot like a Real Cowboy? I was kinda dry and all after that long flight and cheating death does give you a powerful thirst. They have these giant margaritas at the Texas Roadhouse and for just $1 more you get a "kicker" with it. "What's a kicker I asked the waitress?" I couldn't really hear her very well 'cause Waylon hit a particularly soulful part of "Tonight The Bottle Let Me Down" and she probably mistook by head moving to Waylon as "a kicker is a great ass idea". A short time later this enormous margarita shows up with a giant test tube stuck upright in the margarita slush, full of this very strong smelling, amber colored alcohol drink. Well as the great Johnny C once said in "A Boy Named Sue", "What else could I do?!"
So my pretty young waitress shows up awhile later, nods approvingly as she sees the empty kicker tube and the empty gigantic margarita glass and asked, "How did you drink the kicker?" "Well I poured it into the margarita glass and drank it all through the pink and yellow swirly straw. How else could I drink it?" A look of disgust crossed her face as she rolled her eyes upward and turned away and I thought she said, " a Real Cowboy just knocks it back and chases it with a beer.". I can't be sure 'cause just then Hank Williams broke into the chorus of " I Got Them Honky Tonk Blues".
As most of you know, my awesome new Revo was built with Rotax’s latest and greatest: the 912iS fuel-injection engine. It’s an incredible power plant. Purrs like a kitten, and my fuel economy is off the charts. Regardless, there have been some kinks to work out. Of course, this is not unexpected, and the folks at Evolution have been entirely dedicated in their commitment to assist.
Regardless, there is a party with whom I am rather unhappy. It’s the North American Rotax distributor, Kodiak.
Let’s first take the warm-start problem. This was real-time described in my big-trip blog:If I stopped for fuel, I could not startup (and resume flying) for at least an hour. If I started first thing in the morning, let it warm slightly, then had reason to momentarily shut down before actual takeoff, I found myself needlessly stuck on the ground for at least an added hour. When I got home, I found my flying here likewise compromised. Stop for a bathroom break. Stop to exchange passengers. Whatever! No go again for at least an hour.
It was extremely frustrating. A plethora of theories were successively proposed, investigated, and dropped. Lacking their own 912iS expertise, folks at Evolution (in particular, Larry’s dad Phil) worked hard to pump information and guidance from Kodiak, which was somewhat painstakingly passed through to me. By such means, I was directed to try a series of expedients. Diagnostics. Changing components. Putting in new wiring and novel components.
Nothing worked. Making it all the more frustrating, it took a lot of time even to determine if an expedient had worked, because – to tell – the engine had to first be well-warmed, then allowed to cool a bit, though not entirely (turns out calling it a “warm-start” problem is not perfectly descriptive: it always started well if fully warm, and always started well if fully cold; it was the in-between state that was a problem).
This went on for a considerable time. I grew increasingly aggravated with each continued failure.
Somewhat early on, it was divulged Evolution had used an alternate external wiring plan, for the engine, which it is my understanding had been recommended (and evidently was created) by folks at Kodiak. I am also given to understand the same recommendation was made to (and evidently accepted by) several other North American aircraft manufacturers.
Here’s the thing. The standard Rotax 912iS external wiring plan calls for two momentary start switches, which must be simultaneously held during engine start. So near as I can gather, folks at Kodiak evidently guessed American pilots would find that objectionable, and so came up with a plan that uses an external relay in an alternate circuit design, in effort to eliminate need for the secondary momentary switch.
When I was given this understanding, the objective sounded sensible, and much of my work (as directed by folks at Kodiak and translated through Phil at Evolution) centered around seeking to make that alternate plan function as needed.
The essence of the fault (at least beyond the base level), we duly determined, was that the system was shutting off the fuel pumps after, maybe, 1/3rd a second of engine cranking. When the engine was fully cold or fully warm, this was not an issue -- because, in fact, the engine starts just fine within that short period. Where it’s partially warm, by contrast, a little more cranking time is needed. Since it’s fuel injection, it fully depends on the pumps (or at least one of them). No pumping, no injection. Thus, if pumps shut-off before start, you get no start.
We fought it, and fought it, and fought it – with ever-increasing frustration on my part. At several junctures I was at my hangar, tools in-hand, while in three-way conference between myself, Phil at Evolution, and someone named Nino with Kodiak in the Bahamas. Eventually, I found myself on the verge of screaming.
Finally, during a particular telephone conversation, Phil suggested I look at Rotax’s schematic for the standard 912iS external wiring. You should understand, I am not a schematic genius. However, I do have a bit of background experience (I spent several years as an appliance technician), so looking at a schematic (at least one that’s not extraordinarily complex and/or is reasonably presented) is something I am comfortable with. It’s a skill I’m sure I possess in greater degree than folks at Evolution.
Anyway, I examined the standard Rotax-recommended schematic, and compared to the alternate plan that evidently was produced and recommended by folks at Kodiak. With no more than 30 minutes analysis, it was thoroughly, totally and absolutely apparent there was no way (may I say “No way in hell?”) the alternate plan could achieve the engine inputs Rotax intended.
Indeed, I could not believe how thoroughly (yes, I will say it) STUPID is that alternate plan. I do not know who precisely created it. I do not know of a certainty it was someone at Kodiak. I am, regardless, extremely certain the person that did it could not possibly have been operating, when doing so, with appropriate intelligence, care or due regard for consequences.
There are at least four problems with the alternate plan:
1. Engine cranking begins with what are supposed to be emergency-mode engine inputs, as opposed to proper cranking-mode inputs.
2. Within a brief moment after cranking begins, engine inputs switch (via that added relay) to half (and only half) of what is supposed to be engine-crank mode. Because in this “half” mode the negative-side engine input is missing, it provides a direct and precise explanation for the exact symptom (pumps shutting off) we were for so long fighting.
3. Engine inputs remain in this half-engine-crank mode for the entire duration of the engine-run cycle. In other words, inputs do not appropriately switch to intended engine-run mode. One visible consequence of this (I did not realize it was not an intended feature in the interface until studying the official schematic) is the dashboard pump lights remained constantly illuminated during flight.
4. If both engine generators happened to fail, Rotax’s official schematic has provision for manually switching to emergency-mode battery-powering of the fuel pumps (or, again, at least one of them). The alternate plan has no provision for such manual switching. It might, or might not, achieve needed switching automatically, depending on circumstances.
The actual schematics are simple enough (they really are quite simple) I was able to deduce all of this in the space of about 30 minutes. Again, this is in the absence of me being any kind of schematic genius. I instantly felt very appalled (alright, beyond appalled) a supposedly responsible organization and its personnel had evidently foisted such an irresponsible and incompetent product -- as this alternate wiring plan -- upon the flying public.
At any rate, upon realizing this, solution was obvious. It was to rip out all components and wiring as uniquely associated with that (my favorite word for it) “jackass” alternate plan, and replace with wiring and componentry appropriately matching Rotax specs.
It did not take much of a genius to figure that, did it?
Now, do you want to hear the real surprise?
No, it’s not a surprise at all.
Of course, and obviously, once wired according to genuine Rotax specs, the pumps ceased to shut-off after 1/3rd a second of cranking. Indeed, they continue pumping – for as long as it takes – to start. Hence, my warm-start problem was totally and thoroughly solved, instantly.
Well, almost instantly. It killed a long day of rather hard work to do the entire re-configuration, from jackass-alternate plan to Rotax-specified.
I also no longer have bright-green fuel-pump-indicator lights (intended to show running in on-battery-emergency-backup mode) constantly and annoyingly illuminated during the entire time I fly.
And, I am fully confident that, in the extremely unlikely event both engine generators fail, I can easily (and correctly) switch to battery-pump-run backup mode.
Ahhh. Doing it right. It’s not bad thing.
In defense of the great Evolution folk, they were relying on Rotax’s duly-appointed North American representative. There is no fault on Evolution’s part. Larry and Phil were terrific.
I wish what I just described had been my only problem.
Beginning shortly before I left Zephyrhills, one of the Rotax “Lane” lights began to occasionally go into a flashing mode. This is the equivalent of an engine warning light on a car. Since the 912iS has dual/redundant ECUs (referred to as “Lanes”), there are two separate lights, one for each Lane. Anyway, it got worse and worse. By the time I completed my cross-continental trip, Lane A was flashing continuously. The word from Kodiak (again, relayed to me via Evolution) was that it should not be a cause for any real concern. Most 912iSs were doing it, and it was thought to be some kink that needed to be worked out in the monitoring system.
I guess that kind of assurance is good enough to get you on your way for your big delivery trip home, but it’s not a matter you exactly want to drop. You expect the matter to be fully investigated, results to be disclosed, and a solution provided.
To that end, even before leaving Zephyrhills (that was early February) I employed tools as provided by the Evolution team to extract diagnostic log data from my 912iS system, and emailed it to Nino at Kodiak, anticipating he would analyze the data to deduce specifically what was behind my flashing Lane A. Nothing happened.
There was still no report upon completing my big trip, and, in the weeks following, I repeatedly, over and over again, asked for the analysis. Just as many times, I was awarded with zero response.
Eventually I was asked to provide another set of logs. Phil, from Evolution, overnighted me the log-extraction dongle. I invested the time and effort to again extract, and again email. Again, no response. Again repeatedly I asked, and again (just as many times) there was nothing.
A third time I was asked to re-provide logs, and a third time I did so. Again, no response. No analysis. No evidence Nino – or anyone else at Kodiak – had even looked at them.
I finally got irate. Just earlier this week, good ol’ Larry passed on, to Kodiak, a sense of my impatience. Finally, a bit of analysis was done. It does not give us a real and full answer yet, but at least it’s something.
Does it sound as though I’m pretty disgusted with folks at
Yeah. It’s the
understatement of the year.
One other problem (this one
surfaced before I even saw my new Revo) is the 912iS hesitates on
sudden application of throttle. Larry observed this in
early testing, informed me, and sought solution via Kodiak.
What he passed on to me is that a solution is expected via a
firmware update, scheduled for July.
In all, I am truly delighted
with my Revo. Larry's new Rival wing design is positively
sweet. I want to repeat, one-up, I am able to get 85 mph at
2.5 gph. Handling is crisp, precise, light and
immediate. The wing is also relatively short, and fits in
my hagar more easily. I love it.
Story for those who are active in PPG community
I was recently asked to present a digital photography workshop demonstrating how I shoot images and what processing techniques I use on the resulting photographs. The major take home lesson from the talk was that images are no longer made in the field but rather afterward, taking pictures in the field is now a matter of data collection. This approach is especially useful for photographs taken while flying where quick snapshots are the rule. If you are not satisfied with your aerial photographs perhaps applying some of these techniques will help make your photographs jump off the screen. While I do not claim to know what makes an interesting photograph these techniques have helped garer over 500,000 views on images I created and submitted to Google Earth.
I have uploaded a pdf of the workshop power point presentation which shows how to manipulate images and lists all the software resources (free). The pdf may be found here (the file will not embed so you will have to click the link).
Below is a before and after of the same image where the input levels were slightly decreased, contrast was slightly increased, and unsharp mask was applied. Note the apparent increase in resolution and increase in photographic depth.
I know, I know, it ain't a trike. But just so you's clowns don't think I am only a bad apple with an attitude about parachutes I'd like to show you photographic evidence that I may indeed be a bad apple with an attitude but when it comes to rockets-on-a-string I have some experience too. Of my own that is. I have owned a few. Exhibit A, for example, is this photo I myself am taking with my left hand, that clearly shows a BPS centered in the top of the shot, riding along on a downtube and attached to the carabiner D ring connection. See? This very system, by the way, was given to me personally by that parachute expert and old-hangie John Dunham himself, up at Slide Mountain, must have been around 1987 or so. It is a Second Chantz system. I hope you all don't have queasy stomachs.