diamondaviators.net

Maybe I missed it in the DA42 POH, but I'm looking for help with simulation of "zero thrust" for practicing one engine inoperative (OEI) procedures.

Rather than setting one of the Engine Master switches to OFF to actually shut down and feather a DA42 engine (which must be restarted within 2 minutes below 10,000 feet), it's possible to simulate an engine failure and feathering by pulling the throttle back to a small percentage of power. The small amount of engine power should exactly offset the drag produced by a windmilling propeller, resulting in zero thrust from that engine.

My question specifically is what percentage engine power to use for this? I've been given conflicting advice by different instructors: some say 11% power, some say 20% power. This makes a HUGE difference in the amount of rudder required to counter the asymmetrical thrust, especially when the other engine is producing 100% power (such as during simulated critical engine failure after takeoff when a positive rate of climb is required).

I'm guessing the answer might be different for Thielert vs. Austro engines, but I'd like to hear what % power people have been using for the simulated feathered engine.

- Dave

I had been confused by this as well. I had used around 15% but that was an arbitrary value. Last summer we actually measured how much I needed. We shut down the right engine and put the left at 100%. We noted what airspeed was needed to maintain altitude. We then restarted the right engine and determined how much power was needed to match the same parameters as when shut down. Turns out on that day, at that temperature and altitude, we needed 20% power on the right engine. I have been using that value ever since. It may not be exact, and it may depend upon which engine is not operative, but I think it is close enough to keep me in OEI proficiency. I have the 1.7 engines.

I always use 11% but will get a "factory recommended" answer to lay this question to rest officially.

10% was what was taught to me too. Look forward to Jeff's 'factory recommended' answer.

Here is your answer right from Peter Schmidleitner at Diamond Austria

For the DA42 TDI we said: "10 to 11% Load".

For the NG:
Although the test pilots said for "zero thrust" the power lever could be placed to idle, I do not believe this.
We recommend "about 8% Load".

Kind regards,
Peter

Jeff wrote:I always use 11% but will get a "factory recommended" answer to lay this question to rest officially.

Only 8% power on the NG?!!!

Wow, I guess all Austrians must be built like Arnold Schwarzenegger with incredibly strong leg muscles!

I for one am glad that 4 good turns of the rudder trim knob usually solve the problem

CFIDave wrote:Only 8% power on the NG?!!!

Wow, I guess all Austrians must be built like Arnold Schwarzenegger with incredibly strong leg muscles!