summit everest without climbing?

Factual Questions
21

There are two ceilings for helicopters - one is the absolute ceiling at which it can fly, and the other is the absolute ceiling that it can sustain a hover at - the second one is much, much lower than the first. And that’s the answer to your question - the only way a helicopter can fly above its max hover altitude is to be flying forward like an airplane. The summit of Everest is at least 10,000 feet above the highest altitude at which helicopter can hover.

Considering how many bodies litter the slopes of Everest because no one has come up with a safe way to get dead climbers off the mountain, it’s safe to say that no one has figured out how to get up there other than to climb it.

You can’t even parachute onto it, because the summit is actually very small, and the winds are usually quite high. So you’d land, the wind would pull your chute over the side, and the chute would pull you with it. Then you’d probably wind up either being bashed to death on the rocks, or you’d land in some crevasse or gorge somewhere and die, or you’d get really, really lucky and parachute back down to one of the base camps.

22

Sorry,Haj, it was a figure of speech. Maybe I should add more :), :D, :stuck_out_tongue: . I don’t know much about heliocopters and military aircraft, and I really was wondering if we have anything capable of doing this.

23

Again, one occasion, the wind is almost nonexistent. And at least one person has successfully parasailed from near the summit, IIRC, of Everest all the way down to base camp. The roughly 15-minute flight took him from 29,000 feet to about 17,000, allowing for some sightseeing along the way.

The true summit of Everest is a snow dome about the size of a king-size bed, but the surrounding terrain, esp. along the S.E. ridge, is “gently” sloped enough–and certainly big enough–to allow a decent landing site. Accuracy is advised. Make sure you “stick” the landing. The rock-strewn snow field above the Kangshung Face gets progressively steeper, meaning that disconnecting the parachute instantaneously would be imperative before Sam’s unenviable scenario would come true.

A few years ago, an idiot Texan climbing with a mob somewhere above the Hilary Step suddenly whipped out a cowboy hat and started doing a rodeo yell–“yeeee-haaawwww!” Seconds later, he slipped, failed to self-arrest, and lost control. The only thing that prevented him from cartwheeling over the dreaded Kangshung Face was a sharp piece of shale that somehow pierced his snowsuit and kept him suspended until his rather stunned guides could haul him back up.

P.S. He lost his fondness for rodeo yells.

24

Some of the dead can be and have been removed from Everest. Retrieval depends on altitude, conditions, strength of climbing party–and obviously on the assumed wishes of the deceased/surviving family members.

Sometimes dramatic rescues succeed. Several years ago, French climber Chantal Maduit, in one of her seemingly annual failed attempts to summit Everest sans gans, collapsed near the South Summit and had to be dragged by guides and Sherpa almost all the way down to the South Col. Of course, she weighed only 145 pounds or so. (She also needed similar rescue on K2 and recently died on Daliguiri.)

Retrieiving a body is much easier if you allow the dessicating wind and cosmic radiation to lighten the load for you. Of course, a body bag is needed to keep the frozen body parts together, as they become rather fragile and the trip is exceptionally bumpy.

Within a century or two, the monorail scenario will materialize. There’s too much potential tourist money to stop it.

25

As Sam Stone said, there are two overing ceilings for helicopters: In ground efect and out of ground effect. Ground effect is a “cushion” of air that helps support aircraft (including fixed-wing) within about a wing span from the surface (or is it half a wing span?). A wing flies more efficiently in ground effect, so they can fly at a higher altitude IGE. The IGE hovering altitude of most helicopters is well below the altitude of the summit of Chomolungma.

Another factor with helicopters is retreating blade stall. In order to generate lift, a wing must have a certain amount of air flowing over it. When the airspeed slows the angle of attack must be increased to create the same amount of lift – up to a point. At a critical angle of attack the air won’t “stick” to the wing and the wing stalls. This can happen at any airspeed and at any angle of attack. (Don’t worry, it’s not capricious.)

Now consider the helicopter rotor system. At hover and in no wind, the rotor blades have the same airspeed; say, 300 miles per hour for the sake of illustration. If the helicopter flies at an airspeed of 100 miles per hour, the advancing blade has an airspeed of 400 miles per hour and the retreating blade has an airspeed of 200 miles per hour. If the helicopter flies fast enough the airspeed of the retreating blade slows to a point where it can no longer develop lift. The rotor system blows back, chops off the tail boom, and the crew and passengers plummet. Or maybe there is no boom chop, but they plummet anyway. I’ve seen video.

We all know that atmospheric density decreases as altitude increases. An airplane can fly at a higher speed to create the same amount of lift because both wings have the same airspeed. (Indicated airspeed will be lower than the true speed of the aircraft.) Helicopters can’t do this because of their retreating blades. To compensate for altitude they must slow down so there is enough air flowing over the retreating blade to prevent stall. At a very high altitude even a slight breeze may be enough to stall a blade. Consider that stall speed and the top speed of the TR-1 (U-2) surveilance aircraft are seperated by only about five knots.

Assuming a helicopter could reach the summit of Everest, and assuming it has enough power to actually hover, and assuming that there is zero wind, a helicopter might be able to land on the summit. But there aren’t any that have the power to do that. Perhaps a helicopter could be purpose-built for such an experiment? Maybe with extremely long blades? That will take more power. More power? That means more fuel to feed the bigger, thirstier engine. More fuel? That means reduced paylod. Solution? Bigger engine. Which needs more fuel, etc. I suppose it could be done, but why?

An anecdote: Filmmaker/skiier (dang, I forgot his given name) Miller took a helicopter to a slope in New Zealand many years ago. IIRC it was a Bell 47, a three-seat piston-powered aircraft. It could have been two seats, as IIRC one of the skiiers had to be outside on a litter. The helicopter didn’t have enough power to take off with such a heavy load, so it made short hops down the slope until it was low enough to fly off of a precipice. It fell quite a long way before there was enough air density for it to sustain level flight. My memory is fuzzy on this anecdote, but that’s how I remember it.

26
27

Oops…

If a little busted fanny made him loose his’fondness’, well, by God, he wasn’t real Texan to begin with!

28

Ok, I am NOT a Helo expert, so pardon this stupid question, but if the winds are so high there wouldn’t the auto-gyro effect help the hover ability?

29

warmgun: No, autorotation is something else entirely. The problem with the wind at high altitude is retreating blade stall. Let’s assume that at a very high altitude the speed at wich an airfoil will no longer generate lift (stall) is 295 knots. For the purposes of illustration let’s assume that that is a “perfect” given. Now let’s assume a helicopter is hovering in still air at this altitude and its blades are turning at 300 knots. The pilot would probably feel the stall coming, but could fly. Since the retreating blade will stall at 295 knots, the pilot can only move through the air at 4 knots. More than that and he loses it. So he lifts off and is very carefully flying along at 4 knots, and a gust of wind hits him from the direction of flight at 2 knots. The retreating blade which had an airspeed of 296 knots now has an airspeed of 264 knots, which we have given that is below the speed necessary to sustain lift. Crash.

30

I think what you meant to say is sans gants. This has yet to be done, but the accomplishment will indeed be great if ever a climber summits without gloves.

That’s what they said about the Spruce Goose. Boy, did he show 'em. But really, why not? If you’ve got the money to burn.

31

I used to have a Porsche. Nice car, but not very practical. I sold it and got something I could use to haul my stuff. The point is that yes, with enough money you can build a machine that can perform amazing feats – like going to the moon, for example. But you may be left with a one-trick pony. Burt Rutan built an airplane designed to do one thing: To circumnavigate the globe on one fueling. It worked and it was a great achievement, but it was only used once. Someone could probably design and build – at enormous cost – a helicopter that can be used to rescue people from the summit of Everest. But would anyone do it? Would the lives saved justify the expenditure of millions of dollars? It can be said that the people who climb mountains know what they’re getting into and that they accept the risks involved.

Aircraft are a compromise. To you want short-field capability? Then you have to sacrifice speed. Do you want more speed on less power? Then you have to sacrifice payload. Do you want to go high? Then you have to sacrifice payload and economy. Do you want VTOL capability and speed? There goes range. Aircraft that do one thing extremely well give up something else. For example an SR-71 goes fast, but it has to be refuelled shortly after takeoff because it leaks like a seive and burns a lot of kerosene. A Piper J-3 Cub can land on a postage stamp, but it can’t go much faster than about 100 mph. A Mooney is a fast four-seater, but if you want to fill the seats, don’t plan on filling the tanks. A Robninson R-22 is cheap to operate (as far as the word “cheap” can be associated with helicopters) and will take off and land vertically. But on the same Lycoming engine it carries half the passengers of a Cessna 172, goes about 2/3 as fast, and costs about double to operate.

That’s why not.

32

I have my doubts that we could do it, anyway. It’s theoretically possible, but I suspect the rotors would have to be freakin’ big, and that causes materials issues. Rotors that big either have a lot of rotational mass, or they have to be VERY strong. Then you run into transmission problems, torque problems… I think getting a helicopter to hover at an altitude like that is a challenge on the same order as circumnavigating the globe.

34,000 ft is WAY up there. A Twin Huey (the ubiquitous Vietnam Helicopter) has a hover ceiling of about 10,000 ft.

Johnny, what’s the highest hover ceiling you’ve heard of? I’ll bet it’s not much higher than that. 34,000 ft is a whole new ball game. The world altitude record for a helicopter is about that high, and that’s not a hover, and not carrying any load. I think the highest rescue on record is somewhere around 15,000 ft. The highest-flying commercial helicopters (The Aerospatiele Alouette, for example) can fly at about 20,000 ft.

Oh, and there are two different hover ceilings for a helicopter, “In Ground Effect” and “Out of Ground Effect”. The second one is much, much lower. For example, a Bell Jet Ranger as an IGE Hover Ceiling of 12,800 ft, and an OGE Hover Ceiling of only about 8,800 ft.

Needless to say, there would be no ground effect on the top of a mountain peak.

33

IIRC, the highest rescue was somewhere in the 19,000-20,000 ft. range–on Everest.

I’m curious how high one of those forestry helicopters could hover–the choppers that are stripped down to a skeleton.

34

“An extreme example of a high DA and gross weight situation is the Mount Everest rescue of 1996 where a Nepalese helicopter pilot volunteered to rescue climbers after the area contract pilots refused to accept the mission due to the altitude and poor weather conditions. LtCol Maden K. C. of the Royal Nepalese Army understood very well the power requirements of his single engine AS 350. He was the officer that on May 13, 1996, rescued an American and a Taiwanese at an elevation of 20,000 ft. on the slopes of the highest peak in the world. He flew 2500 ft. above the helicopter’s 20,000 ft. service ceiling to get over a ridgeline where he was successful in locating the climbers.”

35

I think 30,000 or so feet is all that is needed here. Not that it’s easy, but better than 34,000.

Who has the money to burn? Who is going to offer the millions of dollars to purpose build a helicopter to have a hover ceiling of over 30,000 ft.?

Put it in the category of things that the technology exists for, but which aren’t useful enough to be worth the cost of building. Same reason no one’s built a 2,000 foot skyscraper. Not because we can’t, just because it’s too damn expensive to be worth it.

36

Since everyone missed it the first time, apparently.

37

[quote]
Johnny, what’s the highest hover ceiling you’ve heard of?.. Oh, and there are two different hover ceilings for a helicopter, “In Ground Effect” and “Out of Ground Effect”. "
I mentioned the latter (although I missed an “f”) but I didn’t go into the difference as I thought I was going to when I started typing. As for your question, remember I fly a Schweizer 300CB. On a “standard day” at a gross weight of 1,750 pounds with the mixture leaned the hovering ceiling is 4,600 feet according to the performance data in the POH. According to the charts, IGE is about 6,250 feet at gross weight and 0ºF with a rich mixture and about 6,950 with a lean mixture. There is no information in the POH for OGE. The R-22 POH has OGE info, but I don’t feel like looking it up right now.

I thought about mentioning the structural issues on the “extremely long blades” I mentioned, but I was preching too much already. You’re correct that materials and structures would need to be strong enough. A lot of the strength of a rotor system comes from its rotation. (Read: Don’t try to hang a heli from its rotor blades if they aren’t spinning.) A long blade would probably have the ability to support the airframe, but there are three issues I can see. First is the speed of sound. If you make a blade long enough the tips can reach SoS. So you can’t have the blades too long or too fast. The second is the strength of the rotor hub. Can it withstand the force of the rotor blades that are trying to fling themselves into space? The third is the strength of the blade itself. Although rotational velocity will tend to make it more rigid, who strong can it be even with the newest composite materials?

We have some engineers on the Board. Maybe one of them could “design” a theorietical helicopter? How long would the blades be? How wide the chord? (I’m sure Bernoulli’s equations are somewhere on the 'net.) How much power would it require? Sam is correct to bring up the materials. Add in the weight of beefy structures. Come on, girls and guys; think of it as a fun exercise! Oh, and no fair building components out of unobtanium. :wink:

38

The technological problem this thread is trying to solve is thus: how to get an aircraft that is capable of sustaining enough lift in a thin atmosphere, with little oxygen for combustion and has vertical take-off and landing abilities. This is not such a pointless problem as some posting here suggest.

I watched a science/technology show called “Springboard” on PBS yesterday in which they discussed the building of a flying robot to explore Mars.
These engineers are facing a technological hurdle perhaps greater than what is being posed here: The density of the martian atmosphere at the surface is equivalent to the density of Earth’s atmosphere at just over 100,000 feet, and the relative lack of oxygen requires alternative power sources.

A google search gave me the following site that contains a java applet that allows one to compare several aerodynamic variables found on Earth vs. Mars: http://www.grc.nasa.gov/WWW/K-12/airplane/atmosi.html

And here is another site containing a NASA whitepaper on the mars flight mission: http://powerweb.grc.nasa.gov/psi/DOC/mppaper.html

One solution that was presented on the PBS show was an aircraft with four wings that flapped like a bird’s wings. Surely, if this could work on Mars, it would work on Earth. The main problem I can see is scaling-up the aircraft to a size that could carry a human (but forget summitting Everest in the thing, wouldn’t it be cool to personally explore Mars by air if they could make it so!)

39

FWIW…On further recollection, the design they depicted on the show for the flying mars robot looked sorta like a dragonfly and had wings that flapped like one. It could also take off and land vertically so that it could leave the main ground rover, fly off, land, pick up a rock sample, take-off, return, land back atop the rover and drop off the sample.

40

It’s not that easy. To find the lift on a wing there are several factors, the most important being the angle of attack. Theoretically, I could probably look up some information and perform some calculations and get an estimate for a given fixed wing, but I’ve never really looked at helicopters. Also, I bailed from aeronautical engineering in college, and doing that sort of thing would give me horrible flashbacks.