Rotax Archives - Get Your Wings

9th July 202010th July 2020

Post lockdown engine blues, Rotax SMD ignition modules

Our Rotax 912UL has never started as well as it does now, but that wasn’t always the case!

Our aircraft had the post lockdown blues and so did we! The first time starting her and she would turn over, but not firing, there was simply nothing there. Others offered the normal advice, you know the normal things people say; make sure the throttle is fully closed, pull the choke fully out and run the electric pump for a couple of minutes! well yes, I had done all of that, next comes the offers to start her for me, they tried and failed too. I remembered an article which said to warm the ignition modules with a hot air gun if you are having trouble starting. Hot air gun in hand I warm the modules for a few minutes, hastily getting back in and pressing the start button and the engine sprang into life! I warmed the engine before shutting down and putting the cowling on. Others experienced similar issues starting her over the next few flights when the engine was cold.

Then the battery gave out, low voltage of a failing battery could cause the issue so this was probably the cause. After replacing the battery we could not start her due to the weather and the next day Gary Masters was due to do a service. Service done, it was time to do a ground run, I hit the start button and she turned over but didn’t fire! Gary came over and poured very hot water over the mags and she starts and runs perfectly. Gary then confirmed our suspicions that the Mags aka ignition modules have both failed!

These Ducati modules have a reputation for failing and being expensive to replace, circa £1,500 a pair. In a BMAA magazine I had read of some recently approved modules from a company called Light Flight who are selling IGNITECH modules, I text the number on their website and shortly after had a phone call from a very helpful Andy Buchan. Andy told me the modules were approved for use by the BMAA and have been in use across Europe for some time. We purchased two modules with long leads and a simple bracket for £320.00 inc P&P, quite a saving, especially as they claim to be longer-lasting due to being mounted within the cockpit away from heat and vibration. The Modules have an option to boost the spark via a 12V feed taken from the starter solenoid switched positive. The boost ensures a full-strength spark at the low starting rpm. There is also a soft-start software option which we have not enabled currently as it doesn’t seem to be necessary.

Now with the new battery and the new spark boosting mags our Rotax starts effortlessly on the button. We could view it as we had to spend £320 or the way we see things is we saved £1,180!

The fitting is not difficult, but not straight forward either, as they are fitted inside the cockpit on the back of the firewall. This means drilling a hole of approximately 25mm to enable the pre-made cables to pass through, we then closed the hole by placing a piece of split pipe over the cable, thus protecting them and filling the hole. The wiring for the boost is simple, consisting of connecting 1 wire from each module to the switched solenoid terminal (Warning, ensure the battery is disconnected before connecting).

We added a backing plate to the bracket to ensure airflow around the modules, they run warm to the touch the manufacturer says up to 50 degrees C. The 2 white blocks are voltage regulators for the supplemental supply and come with the modules pre-wired.

Would I recommend these modules? It’s early days, but with the ease of starting we now have and the fact they have a proven history in Europe, I think it’s worth the extra effort to fit these, not only because of the saving, but they have a spark boost and hopefully a longer life too!

3rd November 2014

Turning a Rotax engine backwards

I have always been told never to turn the Rotax engine in the wrong direction as it will cause damage, but recently seeing someone turn a prop backwards a few degrees I challenged the person who said “what damage could it do!”, this got me Googling it and I found many hits saying it will damage the engine and as many saying it won’t, below is a summary of what I found, I have also emailed Rotax but not had any response!

Turning an engine backwards will only cause an issue if it has a dry vacuum pump.
Turning an engine backwards to re position the prop is preferred as the engine will not fire even if the mags are on as they only work when rotated in the correct direction.
Turning the engine in the wrong direction causes oil to be squirted into wrong places.
Turning the engine backwards or forwards by hand causes no issues.
Turning the engine backwards causes the engine to suck in air, all you need to do is re burp the engine in the correct direction and all is OK.
Turning the engine backwards causes the engine to suck in air and if turned for more than one revolution this may enter the valve train, thus the engine must be vented.

What is the truth and what should one do if the engine has been turned in the wrong direction?

While there would seem to be some truth in a few of the above and others may be pure fiction, I’m not an aircraft engineer and I’m not going to comment on which are correct and which are not, but I what I have found out from 2 Rotax bulletins is this:

A rotation on less than one revolution in the reverse direction of the prop appears to require no corrective action, while a rotation of one or more revolutions in the wrong direction requires the engine to have the venting checked as layout by Rotax. The bulletin says that the rotation of the prop in the wrong direction may cause the ingestion of air into the valve chain.

Rotax references:

SB-912-036

Service Bulletin: Inspection for correct venting of the oil system for Rotax engine type 912 and 914 (series)
SB-912-036 R1 SB-914-022 R1

Cited in Compliance 1.5 – “engines which have had the prop spun for more than 1 turn in reverse direction allowing air to be ingested into the valve train.”

and

SI-04-1997

Service instruction: Venting of lubrication system for Rotax engine type 912 and 914 (series) SI-04-1997 R3

Cited in 1.3 Reason – “and/or had the prop spun in the reverse direction allowing air to be ingested into the valve train.”

I have not included the SB or SI documents as I have not had permission from Rotax, but just google SB-912-036 or SI-04-1997 and you will find the PDF files!

31st May 201416th August 2017

Parachutes everywhere!

I was first to fly in G-CEGL on Saturday so I needed to “burp” the aeroplane! Burping the aeroplane is required as the Rotax engine has a dry sump, so to get oil into the engine and to be able to get a reading of the amount of oil you need to turn the propeller by hand in the correct direction until the engine makes a burping or gurgling sound twice. You can then check the oil level before starting the engine, with our engine and I assume its the same for all Rotax engines of this type, the oil level when cold reads low normally at the bottom of the stick, but once up to temperature it will read about halfway up.

Mike ask if I wanted to do another hours solo today and I said yes, this time I was to practice flying at different speeds as before, but also steep turns and Mike gave me a briefing on this together with testing me on what to do if I got into a spiral dive. Which was to take the power off and roll the wings level, as the aeroplane levels out the nose will come up and at this point we apply full power and climb away.

I was now ready for my flight, but for the first time Mike was happy for me to go straight off on my own. I sat warming up the aeroplane and was ready to go about the same time as Mick, we had all been using runway 19, but Mick went straight up on the nearest runway 29 and I taxied out to 19, as I was back tracking on 19 I heard the parachute plane call “clear drop” which gives you a few mins and had previously been cited by the parachute plane’s pilot that there is sufficient time for you to line up and take off, which is what I did. How on returning I was advised that in future I should taxi off of the runway and hold clear.

My flight was uneventful but on my return to the airfield I call asking if all canopies where down and it was confirmed, so I called and joined base leg, immediately after my call I hear “Clear Drop” as I was unsure if there was enough time I decided to leave the circuit and hold to the east.

Later that day two fellow students achieved their first solo flights, so just a quick shout out to Alan H and Alan B congratulations and well done guys! How was it?