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#1
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The biggest downside to flaps is that they are hard to train for,
since there are few two-seaters that have them. And too many gliders that do have them (I'm looking at you, SGS 1-35), don't have enough of them, so it's too easy to float down the runway. Flaps that go to only 60 degrees aren't enough; it takes at least 85 to reliably kill the float and get onto the ground with authority. Bob I've got to send you a picture of the NG-1 with full flaps out. In fact I need to shoot some landings in it sometime and get some photos of it from the ground. That thing is impressive! I'm pretty sure the handle is limited to about 60 degrees or so but that is more than enough flap. In fact it takes about all the strength in my left arm to get that much flap at a typical 60 mph approach speed. The flaps are the same as a BG-12/16 and run from the root to the aileron. On the few full flap approaches i've done SeeYou has shown an L/D of somewhere around 5. |
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#2
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Due to the lack of a "large span" trainer, Bob K developed the following
page to assist Schreder sailplane owners make the transition. http://www.soaridaho.com/Schreder/St..._HP_flight.htm Even though the page was designed for HPs, it applies to any flaps-only sailplane. Here are a couple other landing videos. http://www.youtube.com/watch?v=BC55ikXmo5I http://www.youtube.com/watch?v=19uZV4wH00 Wayne HP-14 "6F" http://tinyurl.com/N990-6F "Tony" wrote in message ... The biggest downside to flaps is that they are hard to train for, since there are few two-seaters that have them. And too many gliders that do have them (I'm looking at you, SGS 1-35), don't have enough of them, so it's too easy to float down the runway. Flaps that go to only 60 degrees aren't enough; it takes at least 85 to reliably kill the float and get onto the ground with authority. Bob I've got to send you a picture of the NG-1 with full flaps out. In fact I need to shoot some landings in it sometime and get some photos of it from the ground. That thing is impressive! I'm pretty sure the handle is limited to about 60 degrees or so but that is more than enough flap. In fact it takes about all the strength in my left arm to get that much flap at a typical 60 mph approach speed. The flaps are the same as a BG-12/16 and run from the root to the aileron. On the few full flap approaches i've done SeeYou has shown an L/D of somewhere around 5. |
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#3
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The second link should be
http://www.youtube.com/watch?v=19uZV4wH00U "Wayne Paul" wrote in message m... Due to the lack of a "large span" trainer, Bob K developed the following page to assist Schreder sailplane owners make the transition. http://www.soaridaho.com/Schreder/St..._HP_flight.htm Even though the page was designed for HPs, it applies to any flaps-only sailplane. Here are a couple other landing videos. http://www.youtube.com/watch?v=BC55ikXmo5I http://www.youtube.com/watch?v=19uZV4wH00 Wayne HP-14 "6F" http://tinyurl.com/N990-6F "Tony" wrote in message ... The biggest downside to flaps is that they are hard to train for, since there are few two-seaters that have them. And too many gliders that do have them (I'm looking at you, SGS 1-35), don't have enough of them, so it's too easy to float down the runway. Flaps that go to only 60 degrees aren't enough; it takes at least 85 to reliably kill the float and get onto the ground with authority. Bob I've got to send you a picture of the NG-1 with full flaps out. In fact I need to shoot some landings in it sometime and get some photos of it from the ground. That thing is impressive! I'm pretty sure the handle is limited to about 60 degrees or so but that is more than enough flap. In fact it takes about all the strength in my left arm to get that much flap at a typical 60 mph approach speed. The flaps are the same as a BG-12/16 and run from the root to the aileron. On the few full flap approaches i've done SeeYou has shown an L/D of somewhere around 5. |
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#4
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On 8/11/2011 8:01 AM, Tony wrote:
The biggest downside to flaps is that they are hard to train for, since there are few two-seaters that have them. And too many gliders that do have them (I'm looking at you, SGS 1-35), don't have enough of them, so it's too easy to float down the runway. Flaps that go to only 60 degrees aren't enough; it takes at least 85 to reliably kill the float and get onto the ground with authority. Bob I've got to send you a picture of the NG-1 with full flaps out. In fact I need to shoot some landings in it sometime and get some photos of it from the ground. That thing is impressive! I'm pretty sure the handle is limited to about 60 degrees or so but that is more than enough flap. In fact it takes about all the strength in my left arm to get that much flap at a typical 60 mph approach speed. The flaps are the same as a BG-12/16 and run from the root to the aileron. On the few full flap approaches i've done SeeYou has shown an L/D of somewhere around 5. Using crude distance measuring methodology (altimeter for vertical/paced-off distance for horizontal), I eventually concluded the HP-14 I flew, achieved a full-flap final-approach L/D, at 45 knots indicated, of somewhere between 3:1 and 1:1, the latter number being easily approached in even the lightest headwind. I was simply curious, and didn't really care what the 'real' number was, once it became (more or less instantly [happy memory!]) apparent that the risk of undershooting in such an immensely 'approach capable' ship was non-existent. Nonetheless, despite the immense drag of that particular ship's fully-deflected flaps, it remained possible for Joe Pilot to 'throw away' some/all of the flaps' short-field landing capability by flaring 'too fast,' in which case - as others have noted the possibility of doing - you *would* float long and far in ground effect. I don't mean to suggest that every flare/landing need/ought to be a low-energy affair, but if you're flying a large-deflection-landing-flapped ship and routinely taking a longer distance to flare, touchdown and roll-out than your buddies in otherwise similar spoilered ships, you might want to continue learning how to safely extract the unused landing performance that *does* reside in your ship. Regards, Bob W. |
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#5
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In article , BobW
wrote: Check out... http://www.youtube.com/watch?v=PXwy7dsLndM ...for a nice/useful/short video of two flapped landings in an HP-14, owned/flown/filmed by Wayne Paul (and posted here with his permission). Curious reader-pilots may find the following information helpful, should they Nice. Enjoyed the videos. Had the distinct privilege of flying an HP-16 once (Thanks Dr. Jim). It has the infamous "flaps and V-tail of death" that I had always heard spell certain doom. In spite of the hype from know-it-alls who had never actually flown with flaps or V-tails, I found the handling of the V-tail was indistinguishable from that of a cruciform or T tail glider and the flaps were just tremendous fun. In the pattern, I turned final at 600 feet and when the numbers disappeared under the nose I started rolling in flaps. I kept on rolling in flaps until the numbers appeared again. The horizon was way up the canopy at this point. Glanced at the airspeed and it read 60 mph, so I rolled in a little more flap. I don't think I ever actually reached the full 90 degree deflection. When the ground got close enough that I could not stand it, I counted to three (quickly) and flared. Touched down just past my aim point, slightly tail low, and made a very short rollout. Not much different from landing an older Cessna with big flaps and power off. I think flaps for glidepath control on gliders got a bad rap because some models of the Schweizer 1-35 had inadequate flap and were flown by those who were not careful to control their speed on final. |
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#6
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Dr Jim's HP-16 is beautiful!!
http://www.soaridaho.com/Schreder/HP...rst_Flight.htm Wayne HP-14 "6F" "Berry" wrote in message ... In article , BobW wrote: Check out... http://www.youtube.com/watch?v=PXwy7dsLndM ...for a nice/useful/short video of two flapped landings in an HP-14, owned/flown/filmed by Wayne Paul (and posted here with his permission). Curious reader-pilots may find the following information helpful, should they Nice. Enjoyed the videos. Had the distinct privilege of flying an HP-16 once (Thanks Dr. Jim). It has the infamous "flaps and V-tail of death" that I had always heard spell certain doom. In spite of the hype from know-it-alls who had never actually flown with flaps or V-tails, I found the handling of the V-tail was indistinguishable from that of a cruciform or T tail glider and the flaps were just tremendous fun. In the pattern, I turned final at 600 feet and when the numbers disappeared under the nose I started rolling in flaps. I kept on rolling in flaps until the numbers appeared again. The horizon was way up the canopy at this point. Glanced at the airspeed and it read 60 mph, so I rolled in a little more flap. I don't think I ever actually reached the full 90 degree deflection. When the ground got close enough that I could not stand it, I counted to three (quickly) and flared. Touched down just past my aim point, slightly tail low, and made a very short rollout. Not much different from landing an older Cessna with big flaps and power off. I think flaps for glidepath control on gliders got a bad rap because some models of the Schweizer 1-35 had inadequate flap and were flown by those who were not careful to control their speed on final. |
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#7
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On Aug 2, 2:15*pm, BobW wrote:
As for the rollout, how many 1-26 drivers routinely roll no more than 300 feet on a hard surface after touchdown? (And how long does your skid plate last?) I haven't flown one of those in anger, but most of my genuine landouts have been in a PW5. I always pace out the distances afterwards. The usual figures are about 30 paces from a standard cattle farm fence to the main wheel touchdown point, and another 30 paces to the point where I'm stopped. If I call the paces 1m each then that's 200 feet -- from the fence, not from touchdown. Most of the rest of my landouts were in a Club Libelle. I'd say the distances were quite similar. It, of course, has speed limiting trailing edge airbrakes, which also have enough flap effect to lower the stall by ~5 knots. IMHO, large deflection landing flaps on gliders are the best kept sailplane secret in the last half century. I'd love to have some! But the trailing edge brakes as on the Club Libelle, Hornet, Mosquito and I think also the Mini Nimbus and early Ventus seem to give most of the same benefits, plus some extra ones. |
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#8
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On 8/9/2011 10:19 PM, Bruce Hoult wrote:
On Aug 2, 2:15 pm, wrote: As for the rollout, how many 1-26 drivers routinely roll no more than 300 feet on a hard surface after touchdown? (And how long does your skid plate last?) I haven't flown one of those in anger, but most of my genuine landouts have been in a PW5. I always pace out the distances afterwards. The usual figures are about 30 paces from a standard cattle farm fence to the main wheel touchdown point, and another 30 paces to the point where I'm stopped. If I call the paces 1m each then that's 200 feet -- from the fence, not from touchdown. Pacing off - or otherwise striving to find some realistic method of quantifying - one's landing rolls is a highly worthwhile activity, whether at the gliderport (establishes one's required-field-length 'baseline'), or eventually in fields (the field distance *will* be shorter due to the higher drag of the unpaved surface). I usually found my 15-meter Zuni's off-field rolls ranged from 150' to 200', probably averaging 180'. Field surfaces ranged from plowed/disked/dry fields (my personal favorite) to hard-packed dirt (occasionally) and reverting-to-prairie (once). The one G-102 (w. 2 aboard) OFL I made in a plowed/disked/dry field, albeit very slightly downhill but into a good breeze, paced out at 220'. All those distances are for summer conditions at ~5,000' msl. They would've all been less at sea-level, I reckon. Most of the rest of my landouts were in a Club Libelle. I'd say the distances were quite similar. It, of course, has speed limiting trailing edge airbrakes, which also have enough flap effect to lower the stall by ~5 knots. And it's that stall-speed-lowering capability I so love about landing flaps (and their close cousins found on some Glasflugel & Schempp-Hirth designs), when it comes to reducing off-field roll-out risks! IMHO, large deflection landing flaps on gliders are the best kept sailplane secret in the last half century. I'd love to have some! But the trailing edge brakes as on the Club Libelle, Hornet, Mosquito and I think also the Mini Nimbus and early Ventus seem to give most of the same benefits, plus some extra ones. Lacking any experience with those designs' 'flaplike' landing aids, I've resorted to picking pilots' brains whenever I could, trying to get a handle on the ships' drag-devices' pros & cons. One of my broad-brush, tentative, conclusions eventually became few 'club-based' pilots ever really learned (or strove to learn?) how to consistently extract the lowest energy touchdowns from the devices. The conclusion was based on probing, trying to understand the pilots' knowledge limits (both practical and theoretical), and then - when I could - continuing to watch their landings. FWIW, I routinely thought and flew as if the biggest 'unknown risk', directly influence-able by me, in soaring was off-field landings, and - once committed to a given field - the most pertinent thing I could do to minimize the landing-surface-related 'unknowns risk' was to achieve as short a rollout as safely possible. Hence the theoretical attraction to me of landing flaps. Learning their 'unanticipated benefits' was pure gravy! Regards, Bob W. |
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#9
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lower gross weight is also a great way to lower the stall speed and
shorten the ground roll. typical off field distances from first impression in the dirt to stop is around 100 feet (30ish paces) in the 600 lb all up Cherokee. of course that light weight might also be part of why I find yourself in fields so often... Bob - found a couple of itty bitty tears in the fabric from the last field at Dalhart. still way better than that piece of steel, which is still riding in the bed of my pickup! |
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#10
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On Aug 11, 3:58*pm, BobW wrote:
On 8/9/2011 10:19 PM, Bruce Hoult wrote: On Aug 2, 2:15 pm, *wrote: As for the rollout, how many 1-26 drivers routinely roll no more than 300 feet on a hard surface after touchdown? (And how long does your skid plate last?) I haven't flown one of those in anger, but most of my genuine landouts have been in a PW5. I always pace out the distances afterwards. The usual figures are about 30 paces from a standard cattle farm fence to the main wheel touchdown point, and another 30 paces to the point where I'm stopped. If I call the paces 1m each then that's 200 feet -- from the fence, not from touchdown. Pacing off - or otherwise striving to find some realistic method of quantifying - one's landing rolls is a highly worthwhile activity, whether at the gliderport (establishes one's required-field-length 'baseline'), or eventually in fields (the field distance *will* be shorter due to the higher drag of the unpaved surface). I usually found my 15-meter Zuni's off-field rolls ranged from 150' to 200', probably averaging 180'. Field surfaces ranged from plowed/disked/dry fields (my personal favorite) to hard-packed dirt (occasionally) and reverting-to-prairie (once). The one G-102 (w. 2 aboard) OFL I made in a plowed/disked/dry field, albeit very slightly downhill but into a good breeze, paced out at 220'. All those distances are for summer conditions at ~5,000' msl. They would've all been less at sea-level, I reckon. Most of the rest of my landouts were in a Club Libelle. I'd say the distances were quite similar. It, of course, has speed limiting trailing edge airbrakes, which also have enough flap effect to lower the stall by ~5 knots. And it's that stall-speed-lowering capability I so love about landing flaps (and their close cousins found on some Glasflugel & Schempp-Hirth designs), when it comes to reducing off-field roll-out risks! IMHO, large deflection landing flaps on gliders are the best kept sailplane secret in the last half century. I'd love to have some! But the trailing edge brakes as on the Club Libelle, Hornet, Mosquito and I think also the Mini Nimbus and early Ventus seem to give most of the same benefits, plus some extra ones. Lacking any experience with those designs' 'flaplike' landing aids, I've resorted to picking pilots' brains whenever I could, trying to get a handle on the ships' drag-devices' pros & cons. One of my broad-brush, tentative, conclusions eventually became few 'club-based' pilots ever really learned (or strove to learn?) how to consistently extract the lowest energy touchdowns from the devices. The conclusion was based on probing, trying to understand the pilots' knowledge limits (both practical and theoretical), and then - when I could - continuing to watch their landings. FWIW, I routinely thought and flew as if the biggest 'unknown risk', directly influence-able by me, in soaring was off-field landings, and - once committed to a given field - the most pertinent thing I could do to minimize the landing-surface-related 'unknowns risk' was to achieve as short a rollout as safely possible. Hence the theoretical attraction to me of landing flaps. Learning their 'unanticipated benefits' was pure gravy! Regards, Bob W. Since I know SOMEONE will call you on it..... It must have been pretty cozy in the "G102 w/2 on board"! I assume that was a typo, and you meant G103. G-102 (w. 2 aboard) Not that I'll ever be able to afford a different glider, but I would love to have a 'flap only' ship. Simpler (hence lighter) wing, shorter roll -outs, etc. What's not to like? |
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