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#11
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Agreed. On RAS even the normally sane, competent, always-within-his-
limits UH starts telling stories of landing over and between goal posts. :-). -T8[/quote] I have landed on a football field but it was after falling off the roof of the gymnasium. Walt |
#12
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Flaps VS Airbrakes/Spoilers
On Aug 15, 10:55*pm, BobW wrote:
The 'purpose of flaps' - Is this where philosophy enters the aerodynamic world definable by flaps' effect on a glider's polar? .... Where I'm headed with this is, one can reasonably conclude the 'purpose of flaps' is whatever JGP decides, within their aerodynamic capabilities. .... Joe Pilot didn't put the flaps there, Bob the designer did. He had a "purpose", which was probably to lower the stall speed and thus the approach speed and all the other good things that come from that. |
#13
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Flaps VS Airbrakes/Spoilers
On Aug 16, 10:26*pm, toad wrote:
On Aug 15, 10:55*pm, BobW wrote: The 'purpose of flaps' - Is this where philosophy enters the aerodynamic world definable by flaps' effect on a glider's polar? ... Where I'm headed with this is, one can reasonably conclude the 'purpose of flaps' is whatever JGP decides, within their aerodynamic capabilities. .... Joe Pilot didn't put the flaps there, Bob the designer did. *He had a "purpose", which was probably to lower the stall speed and thus the approach speed and all the other good things that come from that. I kind of disagree. From my experience, the benefit of "real" landing flaps is very high drag such that speed increases only slightly when approach is steepened and drops off quickly during round out and landing. They also have the very positive effect of reducing the angle of attack at the tip, giving much better roll response. Look at a '20 in full "crow" mode and the tips almost look like they are bending down relative to inboard part of the wing. My View FWIW. UH (Don't try what I've done at home) |
#14
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Flaps VS Airbrakes/Spoilers
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#15
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Flaps VS Airbrakes/Spoilers
On Aug 17, 8:47*am, wrote:
On Aug 16, 10:26*pm, toad wrote: On Aug 15, 10:55*pm, BobW wrote: The 'purpose of flaps' - Is this where philosophy enters the aerodynamic world definable by flaps' effect on a glider's polar? ... Where I'm headed with this is, one can reasonably conclude the 'purpose of flaps' is whatever JGP decides, within their aerodynamic capabilities.. ... Joe Pilot didn't put the flaps there, Bob the designer did. *He had a "purpose", which was probably to lower the stall speed and thus the approach speed and all the other good things that come from that. I kind of disagree. From my experience, the benefit of "real" landing flaps is very high drag such that speed increases only slightly when approach is steepened and drops off quickly during round out and landing. They also have the very positive effect of reducing the angle of attack at the tip, giving much better roll response. Look at a '20 in full "crow" mode and the tips almost look like they are bending down relative to inboard part of the wing. My View FWIW. *UH (Don't try what I've done at home) I actually kind of agree with you. The purpose of the initial deflection is lift increase/stall speed decrease. By increasing the flap deflection available to the "real landing flap" range, the designer got the high drag/glide-slope control feature without adding a second system. Obviously some designers have chosen having 2 systems instead. If all the designer wanted was the drag, he would have used a drag device. IMHO. Todd |
#16
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Flaps VS Airbrakes/Spoilers
The "Flap-only" system appear most often on homebuilt sailplanes. (Schreder
series, BG-12-16, etc) I am sure the designers realized that simplifying wing construction was one of the advantages of the flaps-only system. BTW, I don't use the flaps to fly a lower my approach speed. I use them for the massive amount of drag that they produce. Wayne HP-14 "6F" http://tinyrul.com/N990-6F "toad" wrote in message ... On Aug 15, 10:55 pm, BobW wrote: The 'purpose of flaps' - Is this where philosophy enters the aerodynamic world definable by flaps' effect on a glider's polar? .... Where I'm headed with this is, one can reasonably conclude the 'purpose of flaps' is whatever JGP decides, within their aerodynamic capabilities. ... Joe Pilot didn't put the flaps there, Bob the designer did. He had a "purpose", which was probably to lower the stall speed and thus the approach speed and all the other good things that come from that. |
#17
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Flaps VS Airbrakes/Spoilers
On 8/16/2011 8:26 PM, toad wrote:
On Aug 15, 10:55 pm, wrote: The 'purpose of flaps' - Is this where philosophy enters the aerodynamic world definable by flaps' effect on a glider's polar? ... Where I'm headed with this is, one can reasonably conclude the 'purpose of flaps' is whatever JGP decides, within their aerodynamic capabilities. ... Joe Pilot didn't put the flaps there, Bob the designer did. He had a "purpose", which was probably to lower the stall speed and thus the approach speed and all the other good things that come from that. Indeed the designer(s) did put the flaps on certain ships, not Joe Glider Pilot. And today it's difficult to come any closer to getting inside the mind of the designer *most* responsible for turning one subset of U.S. glider pilot's minds onto the benefit of large deflection landing flaps than can be done from a link earlier referenced by Wayne Paul... http://www.soaridaho.com/Schreder/St...r_on_Flaps.htm *My* point was intended for JGP inside the cockpit while landing. It indeed may be helpful to be even further inside the designer's mind...but it's not necessary in order for JGP to extract the most benefits from the flaps, so long as he understands their aerodynamic capabilities, whether his understanding is gained entirely empirically or has a theoretically based assist. Regards, Bob W. |
#18
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Flaps VS Airbrakes/Spoilers
On Aug 16, 10:26*pm, toad wrote:
Joe Pilot didn't put the flaps there, Bob the designer did. *He had a "purpose", which was probably to lower the stall speed and thus the approach speed and all the other good things that come from that. Perhaps. But this *is* a pilots' forum and we all know that -- from the pilot's point of view -- the world revolves about him, end of story. I mean if it wasn't for glider pilots, there wouldn't be much point in having glider designers. Ergo, Bob put 'em there to be useful to me, period :-). -Evan Ludeman / T8 |
#19
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Flaps VS Airbrakes/Spoilers
Perhaps. But this *is* a pilots' forum and we all know that -- from the pilot's point of view -- the world revolves about him, end of story. I mean if it wasn't for glider pilots, there wouldn't be much point in having glider designers. Ergo, Bob put 'em there to be useful to me, period :-). -Evan Ludeman / T8 True enough, although Dick was speaking from a solution oriented standpoint that ignored perception issues. Kind of like the engineer on the golf course joke http://www.ahajokes.com/gol010.html I've flown the ASW-20A quite a bit & absolutely loved the combination of high deflection flaps and spoilers. I suspect I'd like a flaps only solution too. Craig -- Using Opera's revolutionary email client: http://www.opera.com/mail/ |
#20
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Flaps VS Airbrakes/Spoilers
At 18:15 17 August 2011, T8 wrote:
On Aug 16, 10:26=A0pm, toad wrote: Joe Pilot didn't put the flaps there, Bob the designer did. =A0He had a "purpose", which was probably to lower the stall speed and thus the approach speed and all the other good things that come from that. Perhaps. But this *is* a pilots' forum and we all know that -- from the pilot's point of view -- the world revolves about him, end of story. I mean if it wasn't for glider pilots, there wouldn't be much point in having glider designers. Ergo, Bob put 'em there to be useful to me, period :-). -Evan Ludeman / T8 The duo discus has always been a great glider but it was not easy to land.The latest version XL has flaps connected to the air brakes,and it has transformed it's approach control to the point it is just as easy to land as a K21.When the total mass is750Kg you need to let the designer do the designing,flaps down,nose down and control the rest with stick and brake just like any basic trainer.It reduces the work load,therfore increases safety. Arn't modern gliders great ! ever looked at a Kesteral 2 flap levers 1 for cruise/thermal second for landing plus parachute release and jettison (2 levers) and then there is the brake. Arn't modern gliders great. |
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