Rotax Engine Operation

[boofhead]

Looking for information on the Rotax 582UL operation. Particularly the rpm to use in climb and cruise, how to use the mixture controls and anything to look out for (possible weak points, causes of failure etc). In a Kitfox.
Appreciate the help...

[Blink182]

With a Two-Stroke you have to be careful descending........ i.e. dont let the prop drive the engine....Throttle closed means low lubrication, so if you dive and keep the prop/engine spinning fast it might go all quiet very quickly.:eek:

[7120]

You can get the info you need here:

Rotax-owner.com* Information Training Support (http://www.rotax-owner.com/) (you'll need to register)

and here:

Aircraft - Distributors (http://www.rotax-aircraft-engines.com/a_searchdoc.aspx)

Good luck

[jonkil]

I put a couple of hundred hours on mine without issue.
Points to remember:

1. Let the water temp always come up to +50c before take off. Not doing so can lead to cold seizure. Maintain max power until clear to a couple hundred feet and slightly decrease it a few hundred RPM and the engine isn't screaming for it's life... remember it is a 2 stroke and running quite high RPM in comparison to a direct drive engine.
2. On descent always do a cruise descent, keeping the RPM relatively high to prevent shock cooling... important this.
3. Use good quality 2 stroke oil miked at 50:1, Shell VSX is excellent. Personally, I prefer the engines without the oil mixer and like to mix my own oil into the fuel.
4. Max RPM depends on gearbox and ratio. It can be a "B" "C" or "E" type box on a 582. Mine had "C" box with 2.58:1 ratio and had max RPM of 6600 and cruised at 5300 and burned 12 to 15 l/h.
5. Mixture controls, simple this one.... there isn't any !
6. Never rev it to high on start.

Weak points:

I think it is all on how the engine is treated, I have found them reliable... the following is a guide.
The carburettor rubbers need inspection every 50 hours for cracking and should be replaced if in any doubt. De-coke is supposed to be done every 100 hours, on mine it was always spotlessly clean... good 2 stroke oil is the key.
Replace the spark plugs at 50 hours. Have spare exhaust springs as they tend to break and require frequent replacement... not really an issue. Make sure you wire tie the springs.
Carry out the set down maintenance schedule as dictated by rotax.
The engine provides a lot of power for its size/weight and c.c and is fairly silent in the kitfox set-up.
The ones I found to have issues (generally) are the engines that are mis-treated... not permitted to heat up properly, long idle periods on descending and use of poor 2 stroke oil.
Also as directed in the previous post.... good info on both those sites.

And if you find this a bit much... I have an absolutely stunning Kitfox with the Jabiru 2200 for sale...Max RPM of 3000.... drop me a PM !!

Jon

[boofhead]

The info was very helpful, thanks.
The engine I am operating has a dual mixture control??
Do you think I could squeeze enough gas into the tanks to ferry your airplane across the pond to the US?

[magpienja]

Not heard of a 2 stroke with in flight mixture control, dont sound a good idea to me to be messing with mixtures in flight with a 2 stroke, weaken the mixture and you are making the lube weaker as well not good.

Nick.

[boofhead]

There are two little knobs that turn in increments (clicks) to reduce or increase the fuel flow to the carbs. One is attached to the long needle valve and the other to a small nylon valve in the top of the carby. Turning the knobs moves the needle in and out, seemingly to adjust the fuel flow. They are just below the EGT gauges and affect the EGT in the same way a mixture control does. I think they only work at low power, but don't want to screw the engine by turning them the wrong way or at all. I try to use them to keep the EGTs similar and about half way on the gauge, but would like to know what they really are. I find no mention of them in the ROTAX manuals. My students (who own the airplane) tell me the original builder said to put them "5 clicks" out from fully closed and that is where they sit, but it is annoying not to know what they are supposed to do, since they could be incorrectly set as far as I know.

[jonkil]

There are two little knobs that turn in increments (clicks) to reduce or increase the fuel flow to the carbs. One is attached to the long needle valve and the other to a small nylon valve in the top of the carby.

Having worked on Rotax engines for years and I never ever saw this. Please take a picture so I can have a look. There is the enriching circuit (choke) for cold starting only and sits to the side of the carb body and usually operated by a coupled cable..... unless he has this connected it to the knob you mention in order to richen the unit. Is there a primer circuit on the engine? If so then the chokes should remain permanently closed.

[boofhead]

Funny you mention it. There is a primer, but no choke. Or at least nothing I can identify as a choke.