If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
Volocopter - safest aircraft in the world
O.K., few of my counterargumenters continue to ignore a safety-device called "Ballistic Rescue System". Why? Just because "What I do not know - I do not like?
You insist at the ability of autorotation as best safety device? Sure it´s one thing, but have a look at the list of the National Transportation & Safety Board at the following link: http://www.ntsb.gov/_layouts/ntsb.av...0-abf8bd4e5421 In this list, you find 1.929 reports starting 1964 until today, only Helicopters and only categorized "FATAL". I have not read all of them, but sure all mentioned Helicopters had the ability of autorotation by design and build. The theoretical ability of autorotation did not safe a single soul in those fatal accidents. I´m convinced, that many of those victims could have been saved with a build-in BRS, knowing of course, that during a long earlier period of time, BRS did not exist and even this days, there is no adequate BRS on the market for most of those (heavy) choppers. Or look through that other list, showing the number of fatal accidents with Ultralights, starting in 1982. http://www.ntsb.gov/_layouts/ntsb.av...3-098dbdc6c804 Sure most of them would have the designed ability to glide to the ground, in case of an engine-failure. But this ability did not prevent any of those fatal crashes. According to German Regulations, all Ultralights must have a build-in BRS. This device has already saved many lives during the last years. Sure not 100%, but a big number. Just two examples out of many: When a Czech made DUO-Banjo came to land at a small German airfield in 2013, the pilot tried to keep hight because he was coming short and was flying over a big forest area. About 500 m before the runway, 100 m above the field, he was to slow and the motorglider with retracted engine went into a sudden spin. He pulled the handle and activated the BRS, crashing into the forest but survived the crash "unharmed". With a common motorglider or glider, he sure would have been killed. Some nice pictures you`ll find at this link: http://www.frankenpost.de/fotos/nach...467709,2624008 An Ultralight with two occupants crashed into a Ka8-Glider in 200 m hight just about 800 m outside a small airfield in Germany. While at short final, the Ka8 with a student on board turned in to its short final, flying into the Ultralight from the right. The Ultralight was stuck in the fuselage of the glider. As the pilot activated his BRS, both aircraft came down outside the airfield, both aircraft heavily damaged, but all three survived with minor injuries. http://www.rhein-zeitung.de/region/l...l#.Vm0z3Xv8Mu2 As I look at those pictures, I´m happy about the fact, that I carry a BRS in my glider, which is fitted to the airframe getting me safely to the ground, instead of carrying a parachute tight to my back, not knowing if I get out in time and in adequate hight in order to get the chute inflated befor I hit the ground and wake-up to see I´m dead. Best regards from Germany Klaus |
#22
|
|||
|
|||
Volocopter - safest aircraft in the world
On Sun, 13 Dec 2015 01:24:19 -0800, Kilo-Bravo wrote:
O.K., few of my counterargumenters continue to ignore a safety-device called "Ballistic Rescue System". Why? Just because "What I do not know - I do not like? I've looked through the Volocopter website twice now and have not seen any mention of BRS or performance details among all the salesy balderdash. The similarities remind me somewhat of the Moller M400 Skycar. To my mind BRS is strictly for last ditch use because it seems to be a destructive device. The crash reports I've read where a BRS was used show that its use always seems to cause at least major damage to the aircraft. Take my example of a Volocopter motor failing: if you need to use the BRS to recover then it also means you get to pay for major repairs or a new Volocopter. Kerching!! More money for Volocopter. OTOH if it would autorotate or can balance thrust across the support disk the cost could be as little as resetting a circuit breaker to up to replacing part of the control electronics or one motor. You insist at the ability of autorotation as best safety device? Not at all. I accept that its useful where there's no other way out, e.g. to Cirrus 22 that suffered total electric failure after entering cloud (IFR rated pilot, but entirely electronic panel), should you have to use it when the problem is engine failure? Thats something all power pilots are trained for. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | |
#23
|
|||
|
|||
Volocopter - safest aircraft in the world
On Sunday, December 13, 2015 at 7:03:36 AM UTC-5, Martin Gregorie wrote:
I've looked through the Volocopter website twice now and have not seen any mention of BRS or performance details among all the salesy balderdash.. The similarities remind me somewhat of the Moller M400 Skycar. To my mind BRS is strictly for last ditch use because it seems to be a destructive device. The crash reports I've read where a BRS was used show that its use always seems to cause at least major damage to the aircraft. Take my example of a Volocopter motor failing: if you need to use the BRS to recover then it also means you get to pay for major repairs or a new Volocopter. Kerching!! More money for Volocopter. OTOH if it would autorotate or can balance thrust across the support disk the cost could be as little as resetting a circuit breaker to up to replacing part of the control electronics or one motor. You insist at the ability of autorotation as best safety device? Not at all. I accept that its useful where there's no other way out, e.g. to Cirrus 22 that suffered total electric failure after entering cloud (IFR rated pilot, but entirely electronic panel), should you have to use it when the problem is engine failure? Thats something all power pilots are trained for. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | Read again about 1/2 way down the page..... "In the unlikely event of a total loss of electricity or total failure of the onboard electronics, causing to stop all motors at the same time, the Volocopter of course can not autorotate to the ground like conventional helicopters. In such an inconvenient situation, the pilot can activate the Ballistic-Rescue-System, which brings him gently to the ground by parachute, together with the Volocopter." Yes, it seems most BRS "saves" destroy the craft, but you're likely to be alive to argue with the insurance company about getting a new craft. ;-) As to "Auto rotate" in "conventional choppers, you need height and/or forward speed for it to work (as far as I know), if your're hovering low, you're sorta "along for the ride" straight down. :-0 |
#24
|
|||
|
|||
Volocopter - safest aircraft in the world
On Sun, 13 Dec 2015 06:37:37 -0800, Charlie M. (UH & 002 owner/pilot)
wrote: "In the unlikely event of a total loss of electricity or total failure of the onboard electronics, causing to stop all motors at the same time, the Volocopter of course can not autorotate to the ground like conventional helicopters. In such an inconvenient situation, the pilot can activate the Ballistic-Rescue-System, which brings him gently to the ground by parachute, together with the Volocopter." Yes, I missed that. Fair enough. As to "Auto rotate" in "conventional choppers, you need height and/or forward speed for it to work (as far as I know), if your're hovering low, you're sorta "along for the ride" straight down. :-0 I don't know enough about choppers to comment. I'd be interested to see what anybody who flies them has to say about this: there must be some inertia in those blades. BTW, it looks as if the BRS system has a dead zone if deployed from a slow or stationary vehicle. The rocket extracts the canopy and shrouds, leaving them fully extended but the canopy still has to inflate. If you look at videos & photos of BRS deployment, you can see that prompt canopy opening depends on the airspeed of the aircraft being rescued. In the material I've seen, the aircraft still had a fair amount of airspeed when the BRS was fired so the canopy was filled while still being trailed by the aircraft. As a result height loss during inflation was minimal. However, if its deployed from a hovering Volocopter, the whole rig would fall until the canopy had inflated. Personal view: given than BRS landings seem to be quite hard, the thought of flying something to which the only way out of any type of emergency is "fire the BRS" is not reassuring. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | |
#25
|
|||
|
|||
Volocopter - safest aircraft in the world
On Sunday, December 13, 2015 at 6:29:14 PM UTC+3, Martin Gregorie wrote:
As to "Auto rotate" in "conventional choppers, you need height and/or forward speed for it to work (as far as I know), if your're hovering low, you're sorta "along for the ride" straight down. :-0 I don't know enough about choppers to comment. I'd be interested to see what anybody who flies them has to say about this: there must be some inertia in those blades. They vary. The common and cheap R22 has very little rotor inertia. If you're hovering higher than maybe five feet then you're going to have a hard landing if the engine stops. Unless you're above 400 ft, in which case you can dive to 55-ish knots, level off, and do a nice flare. If you're doing at least 55 knots then you're ok from any height. It only takes maybe 30 knots to make 200 ft safe. Other choppers with heavier rotor systems can be ok from below 20 or 30 ft zero speed, or above 300 ft, or maybe even less. Things such as the Huey or Enstrom can be cut to zero throttle on the ground, picked up and hover-taxi'd a few meters (or turned around 180º) and set back down softly, all on rotor inertia. I even once saw John "Prickles" de Ridder lift off a Hughes 300 and move it from one side of a fence to the other (turning 180º at the same time) after he'd chopped the throttle. |
#26
|
|||
|
|||
Volocopter - safest aircraft in the world
On Sunday, December 13, 2015 at 11:53:58 AM UTC-5, Bruce Hoult wrote:
On Sunday, December 13, 2015 at 6:29:14 PM UTC+3, Martin Gregorie wrote: As to "Auto rotate" in "conventional choppers, you need height and/or forward speed for it to work (as far as I know), if your're hovering low, you're sorta "along for the ride" straight down. :-0 I don't know enough about choppers to comment. I'd be interested to see what anybody who flies them has to say about this: there must be some inertia in those blades. They vary. The common and cheap R22 has very little rotor inertia. If you're hovering higher than maybe five feet then you're going to have a hard landing if the engine stops. Unless you're above 400 ft, in which case you can dive to 55-ish knots, level off, and do a nice flare. If you're doing at least 55 knots then you're ok from any height. It only takes maybe 30 knots to make 200 ft safe. Other choppers with heavier rotor systems can be ok from below 20 or 30 ft zero speed, or above 300 ft, or maybe even less. Things such as the Huey or Enstrom can be cut to zero throttle on the ground, picked up and hover-taxi'd a few meters (or turned around 180º) and set back down softly, all on rotor inertia. I even once saw John "Prickles" de Ridder lift off a Hughes 300 and move it from one side of a fence to the other (turning 180º at the same time) after he'd chopped the throttle. Great info. I also found this (since I was curious)... https://www.faa.gov/regulations_poli...a/hfh_ch11.pdf I have heard of a "coffin corner" in helicopters that is similar to power planes, that was what I was referring to. The FAA link I provided explains some of this. |
#27
|
|||
|
|||
Volocopter - safest aircraft in the world
If the Volocopter is capable of steering itself it must be able to vary
the thrust (RPM for fixed rotors) of each motor so, with a single motor or rotor failure, the system should be able to maintain controlled flight by varying the other motors. Having said the above, stating that all of the referenced helicopter crashes (with autorotation capability) resulted in fatalities is a bit disingenuous since you also stated up front that they were fatal accidents. Not all of the helicopter crashes resulted in fatalities. And the BRS system is not the cure all. I have one in my Pipistrel Sinus but it scares the hell out of me. If deployed at too low an altitude, the result is to be on the end of a pendulum swinging into the ground. If there are high winds, you'd better be able to get out of the aircraft lest you be killed in the wreck dragging across the ground. And then there's the unforgettable image of the flaming Cirrus gently descending to the ground while the occupants burned to death. I'm reminded of the Piper Cub - an aircraft so safe that it can only barely kill you. On 12/13/2015 2:24 AM, Kilo-Bravo wrote: O.K., few of my counterargumenters continue to ignore a safety-device called "Ballistic Rescue System". Why? Just because "What I do not know - I do not like? You insist at the ability of autorotation as best safety device? Sure it´s one thing, but have a look at the list of the National Transportation & Safety Board at the following link: http://www.ntsb.gov/_layouts/ntsb.av...0-abf8bd4e5421 In this list, you find 1.929 reports starting 1964 until today, only Helicopters and only categorized "FATAL". I have not read all of them, but sure all mentioned Helicopters had the ability of autorotation by design and build. The theoretical ability of autorotation did not safe a single soul in those fatal accidents. I´m convinced, that many of those victims could have been saved with a build-in BRS, knowing of course, that during a long earlier period of time, BRS did not exist and even this days, there is no adequate BRS on the market for most of those (heavy) choppers. Or look through that other list, showing the number of fatal accidents with Ultralights, starting in 1982. http://www.ntsb.gov/_layouts/ntsb.av...3-098dbdc6c804 Sure most of them would have the designed ability to glide to the ground, in case of an engine-failure. But this ability did not prevent any of those fatal crashes. According to German Regulations, all Ultralights must have a build-in BRS. This device has already saved many lives during the last years. Sure not 100%, but a big number. Just two examples out of many: When a Czech made DUO-Banjo came to land at a small German airfield in 2013, the pilot tried to keep hight because he was coming short and was flying over a big forest area. About 500 m before the runway, 100 m above the field, he was to slow and the motorglider with retracted engine went into a sudden spin. He pulled the handle and activated the BRS, crashing into the forest but survived the crash "unharmed". With a common motorglider or glider, he sure would have been killed. Some nice pictures you`ll find at this link: http://www.frankenpost.de/fotos/nach...467709,2624008 An Ultralight with two occupants crashed into a Ka8-Glider in 200 m hight just about 800 m outside a small airfield in Germany. While at short final, the Ka8 with a student on board turned in to its short final, flying into the Ultralight from the right. The Ultralight was stuck in the fuselage of the glider. As the pilot activated his BRS, both aircraft came down outside the airfield, both aircraft heavily damaged, but all three survived with minor injuries. http://www.rhein-zeitung.de/region/l...l#.Vm0z3Xv8Mu2 As I look at those pictures, I´m happy about the fact, that I carry a BRS in my glider, which is fitted to the airframe getting me safely to the ground, instead of carrying a parachute tight to my back, not knowing if I get out in time and in adequate hight in order to get the chute inflated befor I hit the ground and wake-up to see I´m dead. Best regards from Germany Klaus -- Dan, 5J |
#28
|
|||
|
|||
Volocopter - safest aircraft in the world
On Sun, 13 Dec 2015 08:59:38 -0800, Charlie M. (UH & 002 owner/pilot)
wrote: On Sunday, December 13, 2015 at 11:53:58 AM UTC-5, Bruce Hoult wrote: On Sunday, December 13, 2015 at 6:29:14 PM UTC+3, Martin Gregorie wrote: As to "Auto rotate" in "conventional choppers, you need height and/or forward speed for it to work (as far as I know), if your're hovering low, you're sorta "along for the ride" straight down. :-0 I don't know enough about choppers to comment. I'd be interested to see what anybody who flies them has to say about this: there must be some inertia in those blades. They vary. The common and cheap R22 has very little rotor inertia. If you're hovering higher than maybe five feet then you're going to have a hard landing if the engine stops. Unless you're above 400 ft, in which case you can dive to 55-ish knots, level off, and do a nice flare. If you're doing at least 55 knots then you're ok from any height. It only takes maybe 30 knots to make 200 ft safe. Other choppers with heavier rotor systems can be ok from below 20 or 30 ft zero speed, or above 300 ft, or maybe even less. Things such as the Huey or Enstrom can be cut to zero throttle on the ground, picked up and hover-taxi'd a few meters (or turned around 180º) and set back down softly, all on rotor inertia. I even once saw John "Prickles" de Ridder lift off a Hughes 300 and move it from one side of a fence to the other (turning 180º at the same time) after he'd chopped the throttle. Great info. I also found this (since I was curious)... https://www.faa.gov/regulations_poli...uals/aviation/ helicopter_flying_handbook/media/hfh_ch11.pdf I have heard of a "coffin corner" in helicopters that is similar to power planes, that was what I was referring to. The FAA link I provided explains some of this. Good info from both of you. Thanks for posting. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | |
#29
|
|||
|
|||
Volocopter - safest aircraft in the world
On Sunday, December 13, 2015 at 1:56:30 PM UTC-5, Martin Gregorie wrote:
On Sun, 13 Dec 2015 08:59:38 -0800, Charlie M. (UH & 002 owner/pilot) wrote: On Sunday, December 13, 2015 at 11:53:58 AM UTC-5, Bruce Hoult wrote: On Sunday, December 13, 2015 at 6:29:14 PM UTC+3, Martin Gregorie wrote: As to "Auto rotate" in "conventional choppers, you need height and/or forward speed for it to work (as far as I know), if your're hovering low, you're sorta "along for the ride" straight down. :-0 I don't know enough about choppers to comment. I'd be interested to see what anybody who flies them has to say about this: there must be some inertia in those blades. They vary. The common and cheap R22 has very little rotor inertia. If you're hovering higher than maybe five feet then you're going to have a hard landing if the engine stops. Unless you're above 400 ft, in which case you can dive to 55-ish knots, level off, and do a nice flare. If you're doing at least 55 knots then you're ok from any height. It only takes maybe 30 knots to make 200 ft safe. Other choppers with heavier rotor systems can be ok from below 20 or 30 ft zero speed, or above 300 ft, or maybe even less. Things such as the Huey or Enstrom can be cut to zero throttle on the ground, picked up and hover-taxi'd a few meters (or turned around 180º) and set back down softly, all on rotor inertia. I even once saw John "Prickles" de Ridder lift off a Hughes 300 and move it from one side of a fence to the other (turning 180º at the same time) after he'd chopped the throttle. Great info. I also found this (since I was curious)... https://www.faa.gov/regulations_poli...uals/aviation/ helicopter_flying_handbook/media/hfh_ch11.pdf I have heard of a "coffin corner" in helicopters that is similar to power planes, that was what I was referring to. The FAA link I provided explains some of this. Good info from both of you. Thanks for posting. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | No problem,the discussion piqued my interest, thus (as a ex-CFIG) I wanted to know more. I knew there were several issues (regardless of aircraft type) that could get you into trouble, but this thread made me look some more. Thanks to all to help me expand my horizons. ;-) PS, any day I learn something new is a good day, thanks. |
#30
|
|||
|
|||
Volocopter - safest aircraft in the world
Martin Gregorie wrote on 12/13/2015 4:01 AM:
To my mind BRS is strictly for last ditch use because it seems to be a destructive device. The crash reports I've read where a BRS was used show that its use always seems to cause at least major damage to the aircraft. My Phoenix touring motorglider has a BRS. My flight manual makes clear that if the landing is in doubt, it's best to deploy the BRS. Some situations a - Water landing (the aircraft will likely flip over if a landing is attempted) - collision with another aircraft that renders it uncontrollable - loss of power at night out gliding range of an airport - loss of power over unlandable terrain - Pilot incapacitation with a parachute deployment by the passenger The BRS is not considered a "destructive device" in my Phoenix, but a "life-saving" device. There are a number of articles and reports on Cirrus' experience with their BRS. The biggest problem took a while to be realized: pilots were reluctant to use the BRS if they thought they could manage an emergency landing - after all, that's been the training for many, many years. After several fatalities that BRS use would have easily avoided, Cirrus changed it's training and it's manuals to emphasize using the BRS as the first choice, and an emergency landing only if can clearly be conducted with very little risk (eg, engine failure while in the pattern at an airport might be an example). This change in emphasis has resulted in fewer fatalities than would have otherwise occurred, by their reckoning. The remark I remember is "You will survive with few (or no) injuries, and the aircraft will be repairable". -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 - "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm http://soaringsafety.org/prevention/...anes-2014A.pdf |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Space - Safest Journey | neo | Piloting | 12 | January 29th 07 05:26 PM |
Navy commander: C130 plane, among safest aircraft worldwide | Droopy Drawerz | Naval Aviation | 0 | December 19th 05 12:14 PM |
Restored Second World War Aircraft Unveiled | NewsBOT | Simulators | 0 | February 18th 05 09:46 PM |
Dark Blue World aircraft? | JDupre5762 | Military Aviation | 3 | January 1st 04 06:42 PM |