One technique that I learned from an instructor with 30+ years of experience is teaching simulated engine failures (“throttle chops”) by rolling off the throttle on a Robinson only enough to split the needles and bring the engine down to 90% RPM. That way, if the student does not react properly, the rotor speed will not drop below 90% (once it gets to 80%, you are dead; the trip from 90 to 80% in an R22 with the collective still up takes about 1 second).
You can generate the nose yaw and the low RPM horn without chopping the throttle to idle. This also makes sense in helicopters where there is a risk that the engine will actually quit if the throttle is chopped suddenly, e.g., older R44 Raven IIs.
what do you consider an “older” r44 and how are the “newer” ones different in design? thanks, eric h
Eric: Robinson says it is something to do with the fuel injection system. They’ve tweaked the ones that have come off the line in the last year or two to make them less likely to quit. This is only for the Raven II (fuel injected). The Raven Is, such as ours, are more appropriate for flight training due to their relative immunity from the engine quitting when the throttle is chopped.
Hi Phil,
Throttle chops were the one part of training that I thought was particularly dangerous. My instructor would even announce it beforehand and then count down from three to let me know it was coming.
I have alwys thought the idea of only reducing engine RPM to 90% would be much less risky. Although I suppose this really doesn’t truly simulate an engine out experience. And of course the chance of actually having a true engine failure is very remote.
Regards,
Mark D
“That way, if the student does not react properly, the rotor speed will not drop below 90% (once it gets to 80%, you are dead; the trip from 90 to 80% in an R22 with the collective still up takes about 1 second).”
It’s scares me that during my flight training (in an R22 Beta in 1993) no one ever explained this point to me. We never practiced any sort of throttle chop (apart from hovering autos) with my primary instructor and I never realized how quickly the R22 would become a flying brick if the engine quit. We did a ton of autorotations and I was good at them, but it was never stressed to me how little time you have to enter into one should the engine lose power. I had about 20 hours of solo time before another instructor finally surprised me with a throttle chop and was shocked by my slow reaction. Even then, it wasn’t until after I had my private license that someone told me that you only actually have about 2 seconds to act before you’re dead. I guess I am quite lucky the engine never quit on me; I’d be dead!