[Hoverbug]

Originally Posted by Old Fokker

That really sounds technical Hoverbug. Sounds like you know what you're talkin' 'bout. Which would be easier landin' if you lost the prop?

I can tell you from personal experience that a Cessna 150 is a good plane to make a forced landing in. Once you get bigger than that, things start get real interesting when forced landing airplanes off airport. In a twin engine prop, much of the plane's lift comes from the induced lift of the engines' thrust over the wing. Take that away, it becomes a brick, even if the props are feathered. Helicopters do glide, but if the rotor slows even a relatively small amount, it will stall, and unlike an airplane wing, it can't be unstalled again, in which case the blades fold up and you truly are a brick. But if you have either altitude or airspeed (or some combination of both) they can be traded for rotor rpm to make a safe landing. The more mass in the rotor blade, the more inertia will allow it to hold rpms and help resist slowing down due to drag. A Huey has massive blades, so it is a very safe helicopter to autorotate. One of the ironys of WWII or Korean era helicopters was that even though they were very mechanically unreliable, they had blades built like aicraft wings - steel spars, wooden ribs, fabric covering, which were relatively heavy. This meant, that though mechanical failures were common, they were very easy to get to the ground safely. These days, honeycomb or composite rotors can be made light, which give good performance from weight and longevity standpoints, but they don't help you to hold your rpms. A helicopter pilot gets very familiar with the "dead man's curve" a.k.a. the height/velocity diagram, which shows the combination of altitude and airspeed that will allow a dead stick autorotation with a cushioned landing at (ideally) no forward airspeed on touch down. Generally, this means that you do not want to be hovering below about 400' because you wouldn't be able to get enough forward speed to convert to rotor rpms as you pull pitch when flaring out of the autorotative glides.

[jim]

sorry hoverbug, good one old Fokker. I talked or more like had merry banter about the relative merits of both forms of flying at the local aeroclub. The Heli chaps are a great bunch of crazy people but they would have to be wouldnt they. Most civilian heli stuff drops like a brick below 400 feet and no chance of recovery. Forward momentum gets you in safe every time in a plane (nose down and pull up at last minute)!!!!!!well if there is anywhere to land that is. I listened to them talking about autogyroing down, I really would not like to try that.

Originally Posted by Old Fokker

That really sounds technical Hoverbug. Sounds like you know what you're talkin' 'bout. Which would be easier landin' if you lost the prop?