The DA20i pilots manual claims to be based on official Rotax data and provides the following values
75% power -5000 - 16.5 l/h manifold pressures are set with reference to temp and altitude
65% - 4800 rpm - 13.7. l/h
55% - 4300 rpm - 11.1 l/h
Their value for full power is 26.1 l/h (WOT)
If I had known that finding information on this engine, especially on its systems, installation, operation and limitations was going to be such a chore, I would never have bought the engine for the simple reason that obscuring the operating principles of its multiple systems leaves me with no option but to PRESUME Rotax has designed a safe system, with no way of knowing if this presumption is warranted.
For example, we know the engine is fitted with a knock sensor, EGT probes, variable ignition timing, multiple injectors, etc., etc. but there is no description of how these features interact.
So what is the engine response going to be when it is provided with fuel of inferior quality (e.g. below 95 octane)? What will the engine response be to a variety of other conditions? We do not know.
People say "just run it" implying there are no operating limitations apart from the 5800 rpm time limit. I would like to see that in writing from Rotax.
Using a constant speed propeller, I could probably set full power (WOT) down to 4000 rpm I am fairly sure that doing this will break the engine. There are probably a lot other things that will break the engine however Rotax won't tell us what they are, they just give us a not very well written manual telling us what appears to work, but not telling us what will happen if various errors occur.
I am always in favour of new technology, but not if the designers won't tell us in detail how it is all expected to work. Just ask yourself about the failures of modern automobile electronics, do you want to be at 5000 ft over an ocean when the ECU does the equivalent of locking your keys in the car?
"Old technology" like a MAP gauge and a table of values may indeed not be required these days however I don't sneer at those who want it. I am continually amazed at how people forget that aircraft and power plant design is based on the blood of thousands or people who died in the learning of the rules that govern flight.
But maybe that is just me. I am an engineer and I spent six years in an airline engineering division and later in an aerospace company, so maybe I am too conservative.
