Helicopter Pilot Exits, Passenger Flips the Bird

That's why my mom taught me to guard the collective on the ground. Seriously, if we hot swap pilots in our bird, we reduce RPM to 75%, use the friction lock on the collective, and guard it as long as possible. Now you know why :)
 
Let'sgoflying! said:
why only 75%, Bob? Would idle put an extra cycle on it?
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Cycles are not a concern in Robinsons since they are powered by Lycoming engines (O-360 in the R22, O-540 in the R44).

Idle is never used except at engine start, and then only very briefly which you flip the switches and stuff. You immediately roll the throttle up to 55% and wait for the clutch to fully engage and then go to 70-75% which is warm up RPM.

Your question is a good one though in the sense of why not roll it down to 55% on the ground? My answer is a stupid one -- that's what I was taught :)

Actually, my guess is that there's a cooling issue, and 75% is the RPM we use to slowly cool the engine so it doesn't shock cool. Dropping below 75% would raise the possibility of shock cooling.

Here's the deal to remember about helos: they require gobs of power to hover (because the rotor is flying through its own vortices). As soon as you set the helicopter down you're going immediately from close to full power to almost nothing in a couple of seconds -- that why shock cooling is so much of an issue. It's very different than an airplane where you are on reduced power from your descent on through taxiing -- you don't have that sharp power change that a helicopter has.

On a warm day, it can take several minutes of running at 75% to get the CHT down to where you can safely kill the engine.

Hope that helps...
 
Let'sgoflying! said:
why only 75%, Bob? Would idle put an extra cycle on it?
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Not Bob but in my limited experience, 75% RPM (that's nowhere near 75% power because the collective has the rotor unloaded) is well below the RPM necessary for lifting off even briefly and it probably keeps the rotor tips from drooping (plus the engine temp issues Bob mentioned).
 
lancefisher said:
Not Bob but in my limited experience, 75% RPM (that's nowhere near 75% power because the collective has the rotor unloaded) is well below the RPM necessary for lifting off even briefly and it probably keeps the rotor tips from drooping (plus the engine temp issues Bob mentioned).
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Good point, Lance, about rotor droop. Still, I make sure to tell non-helo pilots to bend at the waste when walking under the rotor. Ever at 75%, that rotor is going fast enough to decapitate somebody...
 
RotaryWingBob said:
Good point, Lance, about rotor droop. Still, I make sure to tell non-helo pilots to bend at the waste when walking under the rotor. Ever at 75%, that rotor is going fast enough to decapitate somebody...
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Heck, I wouldn't want to get hit by the rotor at 25%. I was just thinking along the lines of extra "headroom".
 
I read the newspaper article and once again I asked myself.. "don't news reporters proof-read what they write, or are they just that stupid?" The article started off by saying..

"A Helicopter crashed in Hawke's Bay"

[font=Verdana, Arial, Helvetica, MS Sans Serif]As far as I'm concerned, the incident was a far cry from being a actual "CRASH".. considering the chopper had just landed and flipped over, which brings me to the second part of the article. The article went on to say..[/font]

[font=Verdana, Arial, Helvetica, MS Sans Serif]"Pilot Bernie Symonds is believed to have landed."[/font]

Of course he landed. First off you just reported that the chopper had just landed and the passenger was getting out when the incident happened. Secondly.. Did you really think both he and his passenger were going to step out of the chopper when it was still flying several hundred feet above the ground?

I ask you.. "How stupid can reporters get?"

Dakota Duce

"May All Your Flights Be Of Good Weather!"
 
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