Originally Posted by
ww2birds
Hi Bob,
I've been playing with a Powerbox Royal SRS for a new install. Previously I've been a happy user of the SmartFly products which have always served me well. Since I really like the iGyro, if you look at the pricing of the PowerBox products, the Royal SRS, even though quite pricey, is a good deal since it has the iGyro integrated, and has some very nice features regarding power distribution. I have a hybrid setup in my Skymaster Viperjet with the Smartfly unit and an iGyro and it works just fine. I was going to replicate that when I saw the Royal SRS unit.
FWIW, reading this thread with folks worrying about the PB stuff as potential reliability is disconcerting, but lately this forum has turned so sour that we seem to be able to turn a sunny spring day into a problem :-(
[snip]
Dave
Dave,
From your description of the PB with Sbus, and reading up on them, its clear that there is *significant* software inside them. Putting something like that in the critical flight control path always gives me pause, especially given that in this case, its a single point of failure.
I like the Smartfly stuff because its a simple analog battery selector switch, analog regulator, and analog signal boosters for the RX to servo signal link.
We have software on our autopilots that have hundreds of flights and hundreds, if not thousands of hours of hardware-in-the-loop simulation time on them, and we still occasionally have a "what was that" kind of experience - quite a few of which would have caused lost of the aircraft if we didn't have a safety switch to let the safety pilot take back control.
Our autopilots have a safety switch function that allows the control to be taken back from the autopilot to the direct signals from the RX (Futaba FASST in our case). This switch is controlled by a separate micro that *only* looks at the pulses from the manual/auto PWM channel and makes the decision which is in control. Also, the switch is architected to be "fail passive" such that if the autopilot looses power, the RX and servos are still powered and the PWM signal can pass through...
Bob