Jump to content

Rotax in the News

Roger Lee

Recommended Posts

Fuel Injection for the Rotax. I don't know if there will be a retro fit kit, but a highly doubt it and I believe you can still buy an engine with carbs. I believe you'll be able to see one at Oshkosh.





ROTAX, a name that is synonymous with light aircraft, LSA aircraft and even military drones and in a co-operation with Pipistrel today marks a very important milestone in the history for ROTAX with the release of the new fuel injected 912 IS aircraft engine.


This new engine the ROTAX 912 IS produces 100 hp from what is basically the same engine core as the 912 ULS with the exception that the carburettors are gone, now replaced with modern fuel injection. This relieves the engine from carburettor imbalance and provides perfect start-up/shutdown and idle just like a modern car. The choke has gone and the engine responsiveness has been increased substantially along with an approximate 10% reduction in fuel consumption at normal cruising speeds.


As the world's leading supplier of aircraft engines for Ultralight and LSA aircraft, ROTAX aircraft engines have truly revolutionized the aircraft industry. The popularity of these engines continues to soar higher and higher, from the original two-stroke engines through to the modern four stroke engines ROTAX produce an engine for just about every aviation application and many hundreds of non-aviation applications.


The 4-stroke 4-cylinder boxer engines we are now familiar with and known as the ROTAX 912 series started development in 1984 having advanced technology and superior weight/performance ratio and have propelled experimental, Ultralight, LSA aircraft and motorgliders for many years gaining themselves an enviable reputation for reliability, low noise, fuel efficiency and most important actually reaching the TBO times. ROTAX aircraft engines are available in two configurations including fully certified engines as well as noncertified engines; both are very similar and enjoy a fantastic reputation.


Today is a significant milestone for both Pipistrel and ROTAX with the release of the 912 IS engine, ROTAX have chosen Pipistrel as the 912 IS release customer and the engine has been fitted and tested on the award-winning Pipistrel Virus SW aircraft. Those that have flown the aircraft report increased smoothness, faster throttle response, lower idle and most importantly for the environment less fuel consumption for this exciting new engine. Now a little history lesson.1920 The company was founded in Dresden, Germany as ROTAX-WERK AG.1930 Taken over by Fichtel & Sachs AG, the company transfers its operations to Schweinfurt/Germany.1943 The company’s operations are relocated to Wels, Austria.1947 The company’s operations get relocated to Gunskirchen near Wels.1959 This year sees LOHNERWERKE GmbH of Vienna acquiring a majority shareholding.1962 For the first time, a ROTAX engine is installed in a Ski-Doo snowmobile developed by bombardier.1970 This year sees integration of Bombardier and ROTAX. The former Bombardier Inc. branch BRP, now an independent company, uses ROTAX engines in its motorcycles, personal water craft, and snowmobiles.1977 High orders of snowmobile spare engines ROTAX® 185, 248, 284, 294 are also used in Ultralight aircraft.1978 Ultralight engines 501, 505 developed (based on snowmobile engine 503).1982 The company begins development of ROTAX 4-stroke aircraft engines, a landmark in ROTAX history.1983 The company starts producing ROTAX motorcycle engines for APRILIA.1984 Start of sales of ROTAX 912 engines.1988 The company starts producing ROTAX marine engines for Bombardier Sea-Doo watercraft.1989 Type certificate for ROTAX 912A1993 The company starts producing ROTAX motorcycle engines for BMW, Germany.1994 Type certificate for ROTAX 912F.1996 Type certificate for ROTAX 914F.1998 Type certificate for ROTAX 912S.1998 The company starts producing ROTAX engines for Bombardier ATVs.2000 The company begins initiation of The ROTAX Quality Production System (RQPS).2001 Launching of ROTAX 4-TEC 4-stroke engines for Sea-Doo watercraft.2002 This year witnesses the launch of the new 2-stroke semi-direct electronic injection technology: ROTAX 2-TEC engines for Ski-Doo snowmobiles, plus the launch of the ROTAX Kart RM1 with direct drive (without chain).2003 Sale of Recreational Products Group by Bombardier Inc.; Foundation of Bombardier Recreational Products Inc. (BRP) with BRP-ROTAX as part of the new company.2003 Approving BRP-ROTAX as International Design Organization according to JAR-21, the European Joint Aviation Authorities (JAA).2005 85th anniversary of ROTAX is celebrated and 35 years with BRP.2005 912 / 914 Series compliant to Light Sport Aircraft ASTM Standards.2006 Production of the 6 millionth ROTAX engine.2006 582 engine compliant to Light Sport Aircraft ASTM standards.2008 ROTAX stars manufacturing the 1125 cc Helicon liquid-cooled, four-stroke, fuel-injected 72˚ V-Twin for the Buell Motorcycle Company.2009 912 Series TBO (Time Between Overhauls) increased from 1500 hours to 2000 hours2010 914 Series TBO increased from 1200 hours to 2000 hours2012 Release of the new ROTAX 912 IS engine More than 150,000 ROTAX Aircraft Engines have been sold since 1973. Today, ROTAX manufacture the 582 engine series (2-stroke) and the 912 / 914 engine family (4-stroke). All these engines are approved for use with Ethanol 10 fuel, MOGAS and AVGAS. Considering the approved usage of MOGAS and the low fuel consumption the fuel costs of a ROTAX 912 series engine are up to 50 % lower than for a comparable 100 hp air-cooled piston engine. With low operating costs, leading class power to weight ratio, well known reliability, it is no surprise that ROTAX Aircraft Engines are the first choice of more than 200 aircraft manufacturers worldwide and today Pipistrel is proud to be involved as the release aircraft manufacturer for this new exciting milestone for sport aviation.

Link to comment
Share on other sites

An interesting question at and interesting time. You have a few options.

1. When you get up to 1500+ hrs. sell the engine for $10K and put the money you would have spent on the rebuild into a brand new zero

time engine. If you rebuild it is not a zero time engine.

2. To rebuild of your old engine is about $12K+ - $14K when it's all said and done. It can be rebuilt or I hear Lockwood has a short

block to exchange.

3. When you get to 1900+ hrs. switch over to ELSA and the TBO would be an option.


4. Last, but not least. The FAA just issued a legal interpretation. ( Just an interpretation at this time). Not a rule or in writing. It said that

Rotax could not make rules and therefore could not force owners to comply with the TBO. They said owners could comply or use

another method acceptable and approved by the Administrator (FAA). That would be an "on condition inspection" past the 2000 TBO

time as in the GA world. That said this was only a legal interpretation and it may take a court case to sort it out. If you don't follow what

Rotax has issued and you crash and want the insurance to pay they may say you did not follow the MFG's recommendation and say

they are not liable. That goes for any maint. you fail to follow. This may at some point put a mechanic in the hot seat along with the



So the question begs, "Who wants to be the test case?" in court, with the FAA or the insurance company? It couldn't cost more than $10K - $50K.



Don't get all worked up or happy just yet this is just starting to unfold.

There are a couple of items being bandied about SLSA rules, Rotax, SB's and SD's with the FAA so things may change in the future. Some things are being challenged so it's a wait and see.



I am only guessing at the new price for a Rotax 912IS engine only. Maybe $6K more than a 912ULS. So about $26K. This is strictly a guess and I have nothing to back it up.

Link to comment
Share on other sites

I find it interesting that Rotax went for higher efficiency and less emissions on the FI design as opposed to cranking out more horsepower. I also read that the FI model has about 5% less torque at 5100rpm. One commentator posited that the reason could be the tougher emission standards of the EU. Personally, I'm fine with a more efficient engine.


Anyone know if the 5mins at 5800rpm goes away?

Link to comment
Share on other sites

So you want to know what the cost and weight is with a Rotax 912IS in a CTLS? Remember it's a completely redesigned engine. No retro fit for the carb engines.


That one I just got some info on. It is approximately $13K more and 22 lbs more.

( 22 lbs extra isn't an issue when your only 95 lbs and covered with fur, by the way that's 95 solid lbs and no fat.dry.gif)

Link to comment
Share on other sites

Copy and paste:

Retail is not set yet, but will most likely be around 25000, however you must also allow for 3500 for a display to match the engine. Be careful about comparing prices to the existing 100hp engine, this one comes standard with the dual electric fuel pumps in stainless fire approved box. The exhaust is complete and the ring mount installed. In addition it has an integrated air box.

This is NOT designed to replace the current product, it is a new product for those who want fuel economy.

Link to comment
Share on other sites

Obviously I am not the first person to read about the new engine. My reaction is mixed; I really like the fuel injection and higher efficiency (gas mileage); more amps so the you can now plug extra stuff in without worrying about overloading the system. An additional 20 or so pounds of weight and 5% less torque are not what I would have expected, I would have hoped for a bit more power, particularly with the injection system.


More has to come out, but I am not jumping up and down and spending more of my children's inheritance yet, that comes if I find out the fuel injection system can be retrofitted. So, there we are a new (and I expect vastly more expensive) engine that changed very little. I would like to think I am wrong, but.....


See ya in October, Ken Nolde, 840 KN

Link to comment
Share on other sites

Carbs have always been a PTA. I have had mine rebuilt, partially, three times by three difference mechanics since last September, and I saw fuel in the drip trays again today! The "altitude compensation" in the carbs is a joke. My fuel burn is higher at 12,000 DA than at 6,000 for the same rpm. They run way too rich at altitude. If they get the altitude compensation right, I suspect it would make up for the diminished rated power, at least at altitude, since I am getting reduced power at altitude due to the too rich mixture. WF

Link to comment
Share on other sites

Altitude power loss won't change with the fuel injection. You will still loose 3% per 1000'. You may see a better fuel economy, but not a big change in power. The only way to correct that is a turbo.




You have something internally that isn't right with those carbs. It may behoove you to have them stripped, checked and re-assembled. You should not have continued fuel issues when done properly. The vast majority don't have carb issues other than a leaky carb bowl gasket on occasions. Your carbs need to come apart and be check from top to bottom. Something isn't right unless you are just lucky and the gasket has another issue.

Link to comment
Share on other sites

I believe that the 914F used in the MQ-1 Predator already has electronic ignition and fuel injection.



yep,,,in a Rotax class in 2003 , there was a guy from General Atomics [ MQ-1 maker ] who confirmed us that they were installing fuel injection .


In a previous class in 1997, Rotech was already 'testing' a fuel injection installation......it was 'secret' and we were not allowed to look, speak ..think about it.....


so, Rotax waited a long time before getting the actual system...they let 'others' experiment first and learned from their mistakes

Link to comment
Share on other sites



I know you lose max power with altitude, but you lose it faster if you can't lean properly and run too rich at altitude. That's what happens to us now, and if we can get the proper lean at altitude we will have more power and a lower fuel flow.


The carbs just might be OK now, too!



Link to comment
Share on other sites

I corresponded with TL-Ultralight (makes of the Sting and Sirius) on their testing of the 912 ULSi. High level impressions were that it ran smoother, lower noise (the data sheet specifies 79.9 dbA which I believe is 10 dbA quieter than the 912 ULS) and lower fuel consumption. No measurable aircraft performance degredation. No hard data on the fuel consumption and performance as they haven't completed testing.


I don't believe there is published data on the incremental cost of the Si vs. S when fully installed on an aircraft but if we assume $10K, then the Si makes sense on a pure economic basis in Europe. Assume maintenance costs are equal over the TBO life of the engine, fuel costs $8/g and the Si achieves the 20% fuel economy improvement. This means you would save 2000 gallons of fuel over this life or $16,000.


If you go with US prices -- $4/g for 93 octane or $6/g for 100LL -- the savings vary from $8K to $12K. Of course, fuel costs may rise and this doesn't do NPV calculations.


It would seem the US market would be around a break even situation and Europe would have a cost advantage but there are other pluses/minuses of FI which will contribute to an individual's engine choice. With my typical annual flying hours, I have about 10 years before I will have this decision :D .

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...