4 ms·

Why would the VTOL miniplanes described in the article be better than small helicopters, which take off the same way?

mhmiles 10y ago
I’d guess speed and prop redundancy
jpeg_hero 10y ago
aerodynamic stability to glide down to emergency landing area should problem arise. more power efficient in cruise flight.
- woofyman 10y ago
  Helicopters can land without power (autorotate) or if the tail rotator fails. https://en.m.wikipedia.org/wiki/Autorotation https://en.m.wikipedia.org/wiki/Autorotation
  - SamReidHughes 10y ago
    Helicopters are actually safer (than some set of airplanes that might include a bunch of recreational planes), because if something breaks, it's easier to find a place to land.
  - jpeg_hero 10y ago
    Yeah, I know a helicopter pilot, I was shocked when he told me that. Would love to hear a aviation enthusiast compare safety differences and failure modes between helicopter autorotation and plane glide...
    - ohyoutravel 10y ago
      I am not a pilot, but have talked extensively with them and we have some planes in the family. MUCH better to autorotate land a helicopter than to glide land a plane, for a myriad of reasons. Autorotating heli landings result in a bit of a rougher bump upon landing, but otherwise are no big deal. Crash landing a plane is obviously different and results in destroying the aircraft and, likely, people inside.
      - nether 10y ago
        Yeah, I was an aerospace engineer at a helicopter company for eight years. They practiced autorotation landings (full engine shut off) every day, outside my office. They were non-events.
    - xb95 10y ago
      I respectfully disagree with the other comment who said he'd rather take a helicopter. (I'm a private pilot of fixed-wing aircraft.) For General Aviation safety, read the Joseph T. Nall report: https://www.aopa.org/-/media/files/aopa/home/training-and-safety/nall-report/25thnallreport.pdf https://www.aopa.org/-/media/files/aopa/home/training-and-sa... To summarize, helicopters and airplanes enjoy a reasonably similar lethality. Approximately 15-20% of accidents (total) are fatal to one or more occupants. However, if you break it down to fatal-accidents-per-100,000-hours then helicopters are worse (1.5 vs 1.0) at least in 2013. When it comes to general aviation safety, however, the far and away most important factor is the pilot. Unless you get damned unlucky, the vast majority of accidents are either avoidable or survivable if the pilot doesn't do something wrong. In helicopters, a controlled autorotation will be survivable most of the time. In airplanes, a controlled forced landing is the same. Of course, you can have your cake and eat it too -- I recently purchased a Cirrus SR22-TN (airplane) which has a Ballistic Recovery System aka a parachute. If anything goes wrong you can pull the chute and the entire airplane will descend to the ground. :-)
      - mannykannot 10y ago
        The regulations required to make flying cars work at scale would be the end of recreational flying as we know it. Fortunately, it's not going to happen anytime soon.
    - vimalbhalodia 10y ago
      Both are survivable, but in general a helicopter autorotation is much less forgiving. (source: I have a private helicopter pilot license) In a airplane, a loss of engine power translates to slowing down. If you're on top of things, you will notice this and nose-down in order to maintain airspeed. If you fail to notice this, your airplane will stall, but even that can be recovered from by nosing down in time. In a helicopter when you lose power this translates very quickly (with 4-5 seconds) into loss of rotor RPM. Within 1-2 seconds you must change the angle of the blades in order to enter the autorotation configuration - if your rotor speed drops below a certain RPM before you make this change, you drop out of the sky with no chance of recovery. Making this an automatic reaction is a big part of helicopter pilot training. Once you have entered autorotation/glide, the next challenge is finding a suitable place to land. In both cases you ideally need a flat hard open surface, though airplanes generally need a longer area than helicopters. Unfortunately a helicopter has a very poor glide ratio - ~5:1 (5 feet horizontal for 1 ft vertical) while a light airplane has something like ~9:1 glide ratio. Furthermore most helicopters cruse at much lower altitudes (1K-3K ft above ground level) vs. light airplanes cruising 4K-8K ft AGL). So you end up having 1/2 to 1/4 the time and distance to find a suitable landing site. When it comes to the actual landing itself, gliding vs autorotation are different but one is not necessarily more dangerous than the other. In both cases you have a well-defined set of ideal airspeeds, descent rates, etc. which will lead to everyone surviving the experience. And in both cases you don't earn your pilot license until you have demonstrated that you can consistently do this correctly. One more nuance - light airplanes (eg: Cessnas) are easier to glide than heavier/faster airplanes because everything happens slower. Since light airplanes are also the cheapest to operate, they are most often found in the hands of new/inexperienced pilots - it is good that they are forgiving. Meanwhile light helicopters like the Robinson R22 are actually much more difficult to autorotate than larger/heavier helicopters - everything happens faster and is less stable. Unfortunately since these helicopters happen to be the cheapest to operate, they also very often find themselves in the hands of new/inexperienced pilots. This was such a big problem that there is a special piece of federal aviation regulation (SFAR 73) which puts additional training requirements on pilots specifically for the Robinson R22 and R44 models. In the big picture though, general aviation is incredibly safe. The vast majority of non-commercial accidents can be attributed to some form of human error - either poor pilot judgment or lax adherence to maintenance requirements.
_ph_ 10y ago
Planes are way more energy efficient in normal forward flight. And electric multicopters, like the popular camera drones, you don't need much of the mechanics of a traditional helicopter.
tehlike 10y ago
energy efficiency.
- tehlike 10y ago
  http://aviation.stackexchange.com/questions/5191/how-does-the-efficiency-of-a-fixed-wing-compare-to-a-rotary-wing http://aviation.stackexchange.com/questions/5191/how-does-th...
ChuckMcM 10y ago
Pilot training time. At the Hiller Museum in San Mateo one of the docents was talking about how helicopters seem so great but they are so hard to fly with the pilot managing rotor pitch, rotor speed, and countering torque with the tail rotor. A typical quad/hexa/octo copter type vehicle is much easier to fly. (as is a gyrocopter but it cannot really take off vertically)
- foldr 10y ago
  >A typical quad/hexa/octo copter type vehicle is much easier to fly They're easier to fly because they have software providing artificial stability. If you had to control each rotor individually it would be virtually impossible. There's no reason in principle why a helicopter couldn't have similarly straightforward controls.
  - Pyxl101 10y ago
    Yes, I've wondered that. Why not provide a joystick for translation motion, rudder pedals for rotation, and a lever for ascending and descending? Allow the human to provide simple inputs, like: tilt the stick forward to go forward. No other inputs required. Aircraft will remain at the same altitude while it tilts forward and gains airspeed. The computer consumes all of these controls, understands what the human wants to do, and then makes the necessary low-level adjustments. I suppose one obstacle to this plan is that the helicopter would need to be entirely fly-by-wire, and there would be no fallback to manual control. This would likely make the helicopter more complex and expensive.
  - ridgeguy 10y ago
    Helicopters do have sophisticated automatic flight control systems. A brief blurb describing some aspects: http://www.helicoptermaintenancemagazine.com/article/understanding-helicopter-automatic-flight-control-systems-afcs http://www.helicoptermaintenancemagazine.com/article/underst...

I’d guess speed and prop redundancy

aerodynamic stability to glide down to emergency landing area should problem arise. more power efficient in cruise flight.

woofyman 10y ago
Helicopters can land without power (autorotate) or if the tail rotator fails. https://en.m.wikipedia.org/wiki/Autorotation https://en.m.wikipedia.org/wiki/Autorotation
- SamReidHughes 10y ago
  Helicopters are actually safer (than some set of airplanes that might include a bunch of recreational planes), because if something breaks, it's easier to find a place to land.
- jpeg_hero 10y ago
  Yeah, I know a helicopter pilot, I was shocked when he told me that. Would love to hear a aviation enthusiast compare safety differences and failure modes between helicopter autorotation and plane glide...
  - ohyoutravel 10y ago
    I am not a pilot, but have talked extensively with them and we have some planes in the family. MUCH better to autorotate land a helicopter than to glide land a plane, for a myriad of reasons. Autorotating heli landings result in a bit of a rougher bump upon landing, but otherwise are no big deal. Crash landing a plane is obviously different and results in destroying the aircraft and, likely, people inside.
    - nether 10y ago
      Yeah, I was an aerospace engineer at a helicopter company for eight years. They practiced autorotation landings (full engine shut off) every day, outside my office. They were non-events.
  - xb95 10y ago
    I respectfully disagree with the other comment who said he'd rather take a helicopter. (I'm a private pilot of fixed-wing aircraft.) For General Aviation safety, read the Joseph T. Nall report: https://www.aopa.org/-/media/files/aopa/home/training-and-safety/nall-report/25thnallreport.pdf https://www.aopa.org/-/media/files/aopa/home/training-and-sa... To summarize, helicopters and airplanes enjoy a reasonably similar lethality. Approximately 15-20% of accidents (total) are fatal to one or more occupants. However, if you break it down to fatal-accidents-per-100,000-hours then helicopters are worse (1.5 vs 1.0) at least in 2013. When it comes to general aviation safety, however, the far and away most important factor is the pilot. Unless you get damned unlucky, the vast majority of accidents are either avoidable or survivable if the pilot doesn't do something wrong. In helicopters, a controlled autorotation will be survivable most of the time. In airplanes, a controlled forced landing is the same. Of course, you can have your cake and eat it too -- I recently purchased a Cirrus SR22-TN (airplane) which has a Ballistic Recovery System aka a parachute. If anything goes wrong you can pull the chute and the entire airplane will descend to the ground. :-)
    - mannykannot 10y ago
      The regulations required to make flying cars work at scale would be the end of recreational flying as we know it. Fortunately, it's not going to happen anytime soon.
  - vimalbhalodia 10y ago
    Both are survivable, but in general a helicopter autorotation is much less forgiving. (source: I have a private helicopter pilot license) In a airplane, a loss of engine power translates to slowing down. If you're on top of things, you will notice this and nose-down in order to maintain airspeed. If you fail to notice this, your airplane will stall, but even that can be recovered from by nosing down in time. In a helicopter when you lose power this translates very quickly (with 4-5 seconds) into loss of rotor RPM. Within 1-2 seconds you must change the angle of the blades in order to enter the autorotation configuration - if your rotor speed drops below a certain RPM before you make this change, you drop out of the sky with no chance of recovery. Making this an automatic reaction is a big part of helicopter pilot training. Once you have entered autorotation/glide, the next challenge is finding a suitable place to land. In both cases you ideally need a flat hard open surface, though airplanes generally need a longer area than helicopters. Unfortunately a helicopter has a very poor glide ratio - ~5:1 (5 feet horizontal for 1 ft vertical) while a light airplane has something like ~9:1 glide ratio. Furthermore most helicopters cruse at much lower altitudes (1K-3K ft above ground level) vs. light airplanes cruising 4K-8K ft AGL). So you end up having 1/2 to 1/4 the time and distance to find a suitable landing site. When it comes to the actual landing itself, gliding vs autorotation are different but one is not necessarily more dangerous than the other. In both cases you have a well-defined set of ideal airspeeds, descent rates, etc. which will lead to everyone surviving the experience. And in both cases you don't earn your pilot license until you have demonstrated that you can consistently do this correctly. One more nuance - light airplanes (eg: Cessnas) are easier to glide than heavier/faster airplanes because everything happens slower. Since light airplanes are also the cheapest to operate, they are most often found in the hands of new/inexperienced pilots - it is good that they are forgiving. Meanwhile light helicopters like the Robinson R22 are actually much more difficult to autorotate than larger/heavier helicopters - everything happens faster and is less stable. Unfortunately since these helicopters happen to be the cheapest to operate, they also very often find themselves in the hands of new/inexperienced pilots. This was such a big problem that there is a special piece of federal aviation regulation (SFAR 73) which puts additional training requirements on pilots specifically for the Robinson R22 and R44 models. In the big picture though, general aviation is incredibly safe. The vast majority of non-commercial accidents can be attributed to some form of human error - either poor pilot judgment or lax adherence to maintenance requirements.

_ph_ 10y ago

Planes are way more energy efficient in normal forward flight. And electric multicopters, like the popular camera drones, you don't need much of the mechanics of a traditional helicopter.

tehlike 10y ago

energy efficiency.

tehlike 10y ago
http://aviation.stackexchange.com/questions/5191/how-does-the-efficiency-of-a-fixed-wing-compare-to-a-rotary-wing http://aviation.stackexchange.com/questions/5191/how-does-th...

ChuckMcM 10y ago

Pilot training time. At the Hiller Museum in San Mateo one of the docents was talking about how helicopters seem so great but they are so hard to fly with the pilot managing rotor pitch, rotor speed, and countering torque with the tail rotor. A typical quad/hexa/octo copter type vehicle is much easier to fly. (as is a gyrocopter but it cannot really take off vertically)

foldr 10y ago
>A typical quad/hexa/octo copter type vehicle is much easier to fly They're easier to fly because they have software providing artificial stability. If you had to control each rotor individually it would be virtually impossible. There's no reason in principle why a helicopter couldn't have similarly straightforward controls.
- Pyxl101 10y ago
  Yes, I've wondered that. Why not provide a joystick for translation motion, rudder pedals for rotation, and a lever for ascending and descending? Allow the human to provide simple inputs, like: tilt the stick forward to go forward. No other inputs required. Aircraft will remain at the same altitude while it tilts forward and gains airspeed. The computer consumes all of these controls, understands what the human wants to do, and then makes the necessary low-level adjustments. I suppose one obstacle to this plan is that the helicopter would need to be entirely fly-by-wire, and there would be no fallback to manual control. This would likely make the helicopter more complex and expensive.
- ridgeguy 10y ago
  Helicopters do have sophisticated automatic flight control systems. A brief blurb describing some aspects: http://www.helicoptermaintenancemagazine.com/article/understanding-helicopter-automatic-flight-control-systems-afcs http://www.helicoptermaintenancemagazine.com/article/underst...