Originally Posted by
franklin_m
Exactly. And I'd argue such a setup would be the minimum folks should do in order to ensure they stay on the right side of the "undue risk" as noted in the rule.
Actually you've suggested more if the model is IC powered:
Originally Posted by
franklin_m
Simple, just add a return spring on the throttle... FAA expects you to already be taking steps to ensure this does not impose undue risk if something as simple as a battery becomes disconnected. Not only is that a very concerning single point of failure on a large and obviously higher risk toy, to not add redundancy and something as simple as a throttle return spring would seem rather cavalier were I the investigator.
Hands up all those who fly IC powered models who think this is reasonable. For my money, putting a spring of any kind in opposition to a servo is generally bad practice. In this specific case, the spring will have to be strong enough to overcome the resistance of the servo with power off in order to close the throttle. No I don't have numbers but those of us who set up our own control systems know that it takes a few ounces to get the servo moving. So the servo will be fighting the spring all through each and every flight, drawing more current, running the battery down faster, and shortening the life of the servo.
Knee jerk solutions imposed by bureaucrats on the spur of the moment are rarely well thought out.