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
|
|||
|
|||
"Jim Harper" wrote in message om... Mike Borgelt wrote in message . .. some snippage The whole ship chute concept is a bit of a worry. There you are in a large heavy object with absolutely no control. With a personal chute you do have steering on most rigs nowadays. With a whole ship chute would it just ruin your day to have save and then hit the high voltage lines, fall out of a tree, fall over a cliff etc? some MORE snippage Mike Borgelt Actually, Mike, on that we disagree. Unless you are using a square canopy for your personal chute, you have very little choice on where you are gonna land...and hitting the tree, high voltage lines or over the cliff are gonna suck less if you have some aluminum or fiberglass around you. Well, that was my decision for sure. Oh, and keep in mind that as I disagree with you, I do it with all due deference to someone as distinguished in our sport as yourself (no sarcasm, I meant that!) Jim OK, crank these numbers. Consider my Nimbus 2C (Experimental, so I could install a BRS) at 650 Kilos with water (which takes 5 minutes to dump). The gear strut will give 30mm on impact and the tire will give 50mm more. The cockpit shell is just fiberglass with no crush structure. I pop a BRS at 300 meters AGL with the surface wind at 15 knots. What are my chances? Give BRS weights, 'chute diameters and descent rates. Bill Daniels |
#22
|
|||
|
|||
Dave Houlton wrote:
This parachute discussion has me thinking about the rocket-deployed chutes we used to have for hang gliding, and the BRS systems now in Cirrus (Cirrii?) and small Cessnas. Probably no improvement w.r.t weight or cost considerations, but for convenience, comfort, and "always there when you need it" they would seem ideal. I don't actually know the repack requirements, but I would guess they're annually or even longer. Are there any gliders out there today with whole-ship BRS-type chutes? Some of the Russia AC-4 gliders in the US are equipped with them, and the SparrowHawk has it available as a $2200 option. At least one SparrowHawk has it installed. Neither the Russia nor the SparrowHawk people have tested the BRS in a glider yet. -- ----- change "netto" to "net" to email me directly Eric Greenwell Washington State USA |
#23
|
|||
|
|||
Bill Daniels wrote:
I pop a BRS at 300 meters AGL with the surface wind at 15 knots. What are my chances? Give BRS weights, 'chute diameters and descent rates. Infinitely better than trying to bailout, no? |
#24
|
|||
|
|||
Bill Daniels wrote:
"Jim Harper" wrote in message om... Mike Borgelt wrote in message . .. some snippage The whole ship chute concept is a bit of a worry. There you are in a large heavy object with absolutely no control. With a personal chute you do have steering on most rigs nowadays. With a whole ship chute would it just ruin your day to have save and then hit the high voltage lines, fall out of a tree, fall over a cliff etc? some MORE snippage Mike Borgelt Actually, Mike, on that we disagree. Unless you are using a square canopy for your personal chute, you have very little choice on where you are gonna land...and hitting the tree, high voltage lines or over the cliff are gonna suck less if you have some aluminum or fiberglass around you. Well, that was my decision for sure. Oh, and keep in mind that as I disagree with you, I do it with all due deference to someone as distinguished in our sport as yourself (no sarcasm, I meant that!) Jim OK, crank these numbers. Consider my Nimbus 2C (Experimental, so I could install a BRS) at 650 Kilos with water (which takes 5 minutes to dump). The gear strut will give 30mm on impact and the tire will give 50mm more. The cockpit shell is just fiberglass with no crush structure. I pop a BRS at 300 meters AGL with the surface wind at 15 knots. What are my chances? Give BRS weights, 'chute diameters and descent rates. Bill Daniels Hi, Bill. Too many variables there to calculate for me, but I did visit the BRS site to gather some data. Their 680 kg. capacity system is 13.5m in diameter, weighs 16kg, and claims 7.6 m/sec descent rate @ 5000' density altitude. So in your proposed situation you're going to land with about a 15kt vertical component and a 15kt horizontal component. Translating that into G-forces and survivability I'll leave up to someone more knowledgeable... OTOH, I'm glad you picked this particular scenario, because I think its exactly where a BRS system would be invaluable. You're at 300m AGL in an unlandable ship - you pull the BRS handle and 2-3 seconds later you are under canopy. In the same situation what are your chances of popping the canopy, unbuckling, bailing, and deploying your chute in time? Now what if you're spinning, tumbling, or pointed straight down without an elevator? At a sufficient altitude where egress time isn't a big factor, I think the personal vs. BRS calculation could go either way. The closer you are to the terrain at the time of the 'incident', the more a BRS system looks like the only game in town. All IMHO, Dave Houlton |
#25
|
|||
|
|||
Jim Harper wrote:
Dave Houlton wrote in message ... Are there any gliders out there today with whole-ship BRS-type chutes? Dave Hi, Dave. The short answer to your question is, yep! http://www.soaridaho.com/Schreder/HP...S_in_HP-16.htm You can do a google search and find a long discussion regarding this (initiated by me, that time...not the first discussion on this) from around last Christmas (02). Short form: I made the decision to put a BRS 1050 in my HP-16 because: 1. I am a big guy. Whilst I did fit in the glider with a parachute, the ergonomics were challenging. Without a parachute, I am in sumptious luxury. 2. I could. The glider is experimental, and changes are trivial. A certificated glider would be much more difficult to do this in, requiring a 337 which may or may not be possible (I'd bet on not). 3. While the cost was higher than a regular parachute (around $2500, if memory serves, now around $2900) the weight penalty was not significantly higher at 24 pounds for the 1050 softpack model I bought. Repacks are sort of a push, given that they are quite expensive, but only need done every 6 years. I reached the decision after doing a moderately exhaustive search on parachute saves in gliders. Basically, it looked to me like most fatalities would not have been prevented by the usual open the canopy and bail out...given the relative low altitude of most. Read the thread for more on that, please. At any rate, I feel I can get a canopy over me at anything above around 250 feet, perhaps lower, so I have a better margin of safety than if I needed to open the canopy and bail out...I think most believe that you need to start that at around 1500-2000 feet above ground. I believe that my parachute will lower me relatively nose-down, and as such, my legs will protect me to some extent on landing. I feel safer surrounded by the aluminum and plexiglass than if I were on my own under canopy, given that I'll likley not be descending into a prepared drop zone, more likely trees or worse...and I have around 500 sport parachute and military jumps, so I speak from knowledge there. No, thank God, I have not had the opportunity to use it, and hope that I never find out if it'll work...but it comforts me to know it's there. I hope that helps. Jim It does help - thanks, Jim! I'm flying club gliders now, but I expect I'll eventually be an owner - and based on this discussion I'll quite likely opt for an experimental. It just makes sense to me that if you're trying to leave yourself an out for when things go Really Bad, you want that out to be usable in as many phases of flight as possible - including low on tow or in the pattern. BRS seems like the only game in town in those situations. I never put on a chute at all during training (including full-turn spins, of course), but I started thinking more about it this fall when I took my 8-yr-old son for his first glider ride. Along the lines of "I should grab us some parachutes. But I'm not confident he'd be able to get out and deploy, and I'm obviously not leaving without him... Anyway, this is just a pattern tow and a sled ride - we'll never be high enough to use them anyway." Perfectly reasoned but not very reassuring. Dave Houlton |
#26
|
|||
|
|||
"Dave Houlton" wrote in message ... OK, crank these numbers. Consider my Nimbus 2C (Experimental, so I could install a BRS) at 650 Kilos with water (which takes 5 minutes to dump). The gear strut will give 30mm on impact and the tire will give 50mm more. The cockpit shell is just fiberglass with no crush structure. I pop a BRS at 300 meters AGL with the surface wind at 15 knots. What are my chances? Give BRS weights, 'chute diameters and descent rates. Bill Daniels Hi, Bill. Too many variables there to calculate for me, but I did visit the BRS site to gather some data. Their 680 kg. capacity system is 13.5m in diameter, weighs 16kg, and claims 7.6 m/sec descent rate @ 5000' density altitude. So in your proposed situation you're going to land with about a 15kt vertical component and a 15kt horizontal component. Translating that into G-forces and survivability I'll leave up to someone more knowledgeable... Dave Houlton OK, Dave, good numbers. This asks me to add 16 Kilo's (35 pounds) to the non-flying parts of the glider for which I get a 15 knot descent rate when deployed (Maybe less since I will be dumping ballast like crazy.) With a 15 knot wind I would probably whack an obstacle at 20 knots. (Probably survivable - with injuries.) BTW, if I'm getting dragged by an open 'chute in that 15 knot wind, how do I dump the 'chute? I seem to recall that the price of this system is about $3500 - presumably not installed. What would be the installed price? Bill Daniels |
#27
|
|||
|
|||
|
#28
|
|||
|
|||
Bill Daniels wrote:
OK, crank these numbers. Consider my Nimbus 2C (Experimental, so I could install a BRS) at 650 Kilos with water (which takes 5 minutes to dump). The gear strut will give 30mm on impact and the tire will give 50mm more. The cockpit shell is just fiberglass with no crush structure. I pop a BRS at 300 meters AGL with the surface wind at 15 knots. What are my chances? Give BRS weights, 'chute diameters and descent rates. My understanding is the "whole glider" German rescue systems will lower the glider nose down at about 40 degrees or so. If it is more level, it is likely to oscillate wildly so much the descent and impact can't be controlled. So, the landing gear is irrelevant, but the cockpit structure is extremely important. The nose must absorb the "landing". A Nimbus 2 might be a poor candidate for installing a system that won't be tested, except when you really need it. Your safety might be better served by selling the Nimbus and buying newer glider with a more crash tolerant cockpit. At least in the US, crashing while landing (meaning the last 100' of altitude) still claims more pilots than unsuccessful bailouts. -- ----- change "netto" to "net" to email me directly Eric Greenwell Washington State USA |
#29
|
|||
|
|||
"Eric Greenwell" wrote in message ... Bill Daniels wrote: OK, crank these numbers. Consider my Nimbus 2C (Experimental, so I could install a BRS) at 650 Kilos with water (which takes 5 minutes to dump). The gear strut will give 30mm on impact and the tire will give 50mm more. The cockpit shell is just fiberglass with no crush structure. I pop a BRS at 300 meters AGL with the surface wind at 15 knots. What are my chances? Give BRS weights, 'chute diameters and descent rates. My understanding is the "whole glider" German rescue systems will lower the glider nose down at about 40 degrees or so. If it is more level, it is likely to oscillate wildly so much the descent and impact can't be controlled. So, the landing gear is irrelevant, but the cockpit structure is extremely important. The nose must absorb the "landing". A Nimbus 2 might be a poor candidate for installing a system that won't be tested, except when you really need it. Your safety might be better served by selling the Nimbus and buying newer glider with a more crash tolerant cockpit. At least in the US, crashing while landing (meaning the last 100' of altitude) still claims more pilots than unsuccessful bailouts. Eric Greenwell Washington State USA OK, good info Eric - now we are getting down to it. To summarize the thread so far: The BRS requires a reinforced cockpit to absorb the non-trivial landing impact forces. Most accidents involve premature termination of tow or landing errors where a BRS 'chute wouldn't help anyway. Or perhaps, mid-air collisions at an altitude where a personal 'chute is the equal for a BRS for survivability. A BRS is likely to require non-trivial pilot training and discipline in its operation and maintenance. Injuries should be expected with the used of either personal or BRS 'chutes. On the other hand, taking the 'chute off the back of the pilot and putting it on the glider adds significantly to ergonomics and comfort. The BRS can be deployed at low altitudes where a pilot with a personal 'chute is unlikely to make a successful egress. This altitude band favoring a BRS probably expands where the pilot is old or infirm. Maybe it's something to think about on a new glider but retrofitting an older glider is problematical. A BRS is perhaps a useful option but not a panacea. I remain skeptical but open to ideas. Bill Daniels |
#30
|
|||
|
|||
Dave Houlton wrote:
Jim Harper wrote: Dave Houlton wrote in message ... I believe that my parachute will lower me relatively nose-down, and as such, my legs will protect me to some extent on landing. I feel safer surrounded by the aluminum and plexiglass than if I were on my own under canopy, given that I'll likley not be descending into a prepared drop zone, more likely trees or worse...and I have around 500 sport parachute and military jumps, so I speak from knowledge there. Jim It does help - thanks, Jim! I'm flying club gliders now, but I expect I'll eventually be an owner - and based on this discussion I'll quite likely opt for an experimental. It just makes sense to me that if you're trying to leave yourself an out for when things go Really Bad, you want that out to be usable in as many phases of flight as possible - including low on tow or in the pattern. BRS seems like the only game in town in those situations. http://brsparachutes.com/PI_saves.mgi |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
AOPA Stall/Spin Study -- Stowell's Review (8,000 words) | Rich Stowell | Aerobatics | 28 | January 2nd 09 02:26 PM |
Parachute fails to save SR-22 | Capt.Doug | Piloting | 72 | February 10th 05 05:14 AM |
Puchaz spin count 23 and counting | henell | Soaring | 116 | February 20th 04 12:35 AM |
Cessna 150 Price Outlook | Charles Talleyrand | Owning | 80 | October 16th 03 02:18 PM |
AOPA Stall/Spin Study -- Stowell's Review (8,000 words) | Rich Stowell | Piloting | 25 | September 11th 03 01:27 PM |