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Discussion in 'Flight Following' started by RotaryWingBob, Sep 19, 2007.
Good info...nicely presented too! Thanks.
I'm not a helicopter pilot (only a few minutes dual in an R44) but I found the MSX helicopters far easier than the real thing. X-Plane has a much better simulation.
Just dropping in here...did a discovery flight today in a 300CBi. 1.0 Dual Rotary now in the logbook, a pretty cool addition.
Deciding between pursuing an Instrument Rating or a Rotary add-on this summer. Both fun in their own ways, and both a challenge.
Just as an aside, you can get your commercial rotorcraft with just 150 hours, and you do not have to have a private rotorcraft first, you can go straight from any category (i.e. private ASEL to commercial rotorcraft). Only 50 of those hours need to be in helicopters, and it would take roughly that long to knock out the commercial requirements anyway.
Wow, had no idea! So it might only take an additional 10-15h to knock out a commercial certificate...great information, thanks.
I really have to figure out my own needs, since I don't own an aircraft and I live at least a half hour drive from the closest place to rent anything. Have to decide if I want to go long distances, or stay local and do something more "hands on"... and there's the cost factor. Right now I'm paying $180 for 145kts (SR20), so I have to figure out if I want to pay $350 for 80kts (300C).
What you are refering to here is called "Settling with Power". In order to produce this situation you must first descend vertically into the downwash from the main rotor.
Just hovering in one spot with no downward motion will not produce it.
Correct. You could settle with power while trying to hover at your max hover height OGE. It would take a gust of wind to get the aircraft to "settle."
Of course if you're not able to take-off vertically it's because lack of power/lift from being either too heavy or too high of DA. Same principle that fixed-wing encounter. IGE requires less power because induced flow is less. So you stay IGE and build up speed. After ETL (20kts ish) which also further reduces induced flow and rotor vortices, then you can climbout at a reduced power.
Yup. When I was flying the HH3F we would depart on missions at max gross and always did a rolling take off to get through translational lift for a little added safety margin for climbout in case one of the engines decided to get grumpy.
Skids are for kids!
I went looking for this information this morning and was afraid that Bob's page would be gone since he has been gone himself for a couple of years. Thankfully it is still there and offers a great summary of fixed vs. fling wing operations. Here is the info incase one day his page leaves the Internet.
Not true, most max performance takeoffs are done straight up , usually to clear an obstacle. Also, all helicopters have performance figures called Hover-in ground effect and out of ground effect. So the aircraft can hover up to those altitudes, without "falling into it" as you say. Hope that helps. Glenn
No, runways are for beauty queens, real pilots land on helipads!
HOLY Necropost! I said that 8 YEARS ago! Yeah I know now, I was referring to vortex ring state or "settling with power"
I was 13 years old when I posted that (wow I've been on this board way too long) cut me some slack.
Who let a 13 yr old in here? This is an adult forum! Then again, some 13 yr olds know more about flying than me.
like anyone on here is an adult
Ok, helicopter guys, explain the science behind this :
Flying over it wouldn't be problem. It would be no different than a FW. Flying down into it from a hover on a windy day could pose a problem. At an OGE hover, a helicopter is already using more power than in forward flight. If the winds were descending into the hole at a high rate, that would create a large increase in induced flow. More induced flow = more induced drag. That increase in drag could exceed the helicopter's power reserve to counter it. Also, the simple fact that descending air (down draft) would be trying to push the helicopter down, would create a rise in power required as well.
The link/news story sounds like BS to me. Flying HEMS, I regularly flew over the biggest open pit mine in the US (or so I was told) going into a small clinic in Morenci, Arizona almost daily. On one occasion, a truck had overturned at the bottom and we flew in to pick up the patient there. When I switched bases, from there we had a regular run over the open pit mine in Bisbee, Arizona. Of course I would avoid flying directly over the top if possible in case of engine failure, but we were always right on the edge near a road. Never once had any sort of problem at either location. Just my 2 cents.
Pure media sensationalism and hype, nothing more.
Cool air in the deep hole interacting with warmer surface air to create turbulence but, nothing life threatening unless flying real low. At other times the hot sun hitting the hole’s slope at essentially a perpendicular (equatorial) angle will generate considerable updraft on that side while the shaded side generates cool air, and the vortex.
In addition to the above, even without appreciable turbulence, substantially heated air inside and right above the bowl will have a significantly higher DA than the surrounding air. We see this in mountain craters and even at the end of blind canyons routinely, with huge losses in aircraft performance, just as the textbooks say, both in Helis and planes. A Cherokee 180 got caught in one a few years back in Idaho and sunk to the deaths of all four aboard.