Sikorsky S-76: Ask Nick Lappos
EAA had 5 x C+'s, S/N's 474, 475, 476, round-dial and S/N's 497 & 521, IIDS machines. The first three a/c were relatively light and flew very well. The two IIDS machines were, IIRC, somewhat more troublesome at times (no idea why). I recall being told that IIDS became standard fit after a certain S/N, but stand to be corrected on whether or not that is factually correct.
It wasn't poor track and balance. I was there when they were eventually put into service and the problem was the bifilars.
The aircraft operated in roughly 5 hour sessions but with no shutdowns during that time. Given that the flights normally took 16 minutes there was then 14 (unlogged) minutes of ground running before the next scheduled take-off.
In effect, the bifilar rattled around for twice the logged time and wore out much earlier than anyone had experienced before.
I was a maintainer and I actually thought that the C+ was pretty good considering the crappy environment in which they had to operate. The MRB's would be dripping with black slime at the end of the day: likewise the Arriels were full of black slimy/tarry rubbish when they were opened up for a Bulletin I can't remember the details of, but I do recall the Turbomeca man was horrified.
The aircraft operated in roughly 5 hour sessions but with no shutdowns during that time. Given that the flights normally took 16 minutes there was then 14 (unlogged) minutes of ground running before the next scheduled take-off.
In effect, the bifilar rattled around for twice the logged time and wore out much earlier than anyone had experienced before.
I was a maintainer and I actually thought that the C+ was pretty good considering the crappy environment in which they had to operate. The MRB's would be dripping with black slime at the end of the day: likewise the Arriels were full of black slimy/tarry rubbish when they were opened up for a Bulletin I can't remember the details of, but I do recall the Turbomeca man was horrified.
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Can't say I agree with you on that. At least initially they were tearing themselves to pieces in flight due to poor track and balance. I've never seen a blade flying so far out of track on an S76 that was supposed to be serviceable. And the #2 GEN's weren't lasting very long in summer either.
Generator won't last long in the summer if you run the aircon with the engine at idle...
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Sir i would like to understand the merits and de-merits of having "offset vertical fin with ventral fin over conventional centralised fin in single main rotor and tail rotor helicopter".......am a student of aero.
If you are referring to a canted tail rotor, then Nick Lappos explains it somewhere deep within the S76 thread, as a means to provide a vertical thrust element to expand the aircrafts longitudinal C&G. Loads of amazing info on this site if you are prepared to dig down and search for it.
Regarding the Go-Around function, the manual states FD shall not be coupled below 60kts. What would happen if GA was selected below this airspeed? Would it simply not work? Is the 60kts to do with stability regarding the yaw holding heading below 40kts opposed to roll? Just curious...thanks.
Loads of amazing info on this site if you are prepared to dig down and search for it.
Sometimes you swear they would argue with a sign post.
