Note all this discussion on circuit speed in strong wind conditions, and a safe speed near the ground is essential. But aspects of the discussion hit on a hobby horse of mine. Whether 1/2 or 1/3 of estimated wind speed is somewhat secondary and probably less than 3~5 knot delta to the ~18 knots associated with 1.5Vs. More importantly though, the pilot's focus should not be on speed [viz., ASI], rather the horizon attitude that leads to that airspeed. And trim for zero stick force once the airspeed is established and don't touch trim again until stopped on the ground. The minor stick forces/loads can be tolerated for the few seconds from check one and two. Pupils/pilots who focus on the ASI will often vary airspeed, particularly in final turns. The key is to establish the horizon attitude that produces the required airspeed, and maintain it precisely. Keep that specific 'fly speck' on the horizon. Particularly in the base and final turns. A pilot who looks at the airfield during these turns will loose airspeed. Glance at the landing area until you decide the circuit turn is necessary, then ensure the horizon attitude is maintained during the turn. The focus in circuit turns is not the ASI or the airfield: it should be on keeping the 'fly speck' on the horizon out front. [Which is where you focus when thermalling at altitude]. As mooted, I am against changes to trim close to the ground, in fact I teach that only one control should be changed at a time, be it back stick or airbrake. Changing only one means you know what is causing the effect. Experienced pilots may be capable of increasing airbrake and back stick close to the ground, but pupils should apply one at a time. I prefer a fixed airbrake position and progressive backstick for check one and two. If that is applied wrongly, then close the airbrakes and try check two for the last time [only until landing attitude 'fly speck' is established on the horizon - don't over rotate]. Don't confuse things with trim changes at this time! Maintaining horizon attitude is where the focus should be, the more precise the better. My two cents worth. Alan Wilson Would rather be above 8,000 than on the ground talking about flying. See also www.canberragliding.org PS. [At Canberra we have had discussions on approaching 5 knots faster with full [all] airbrake v 1.5Vs and half brake approach and the panel prefers the former - the latter can lead to pupils flying close to the ground in check two for extended periods] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Greg Quick Sent: 10 September 2001 4:34 PM To: [EMAIL PROTECTED] Subject: RE: [aus-soaring] Downwind leg airspeed The 1950/60's NGS's got the majority of the gliding rules and procedures spot-on. Any fiddling around the edges should have clear saftey improvements and solid fustification. The wind allowanace debate has been going on since about 1990 when the rules were changed without general acceptance, without any clear saftey improvements and without justification. * The rules were changed ten years ago with little or no dissicion among the clubs. Most experienced instructors did not accept meddling with procedures when those changes increased the risks for our inexperienced or uncurrent pilots with zero justification and NO increase in saftey. * The original reason for this change is that flying the downwind at 1.5Vs + 1/2 wind is too fast ( in a Jantar). A previous post suggesting a difference of a trival 8 seconds is in line with the feelings of most senior experienced instructors when the change was introduced. An additional line was that power pilots do this (change attitude and trim close to the ground), why can't glider pilots? * It is sheer luncay to adopt power procedures just because we can. Too many people forget that power procedures are established on the principle that if you do not like the approach, you should 'go around'. This is not an option in a glider. Anything that produces a stable platform from which to make decsions is good. Anything that increases the workload of the pilot and de-stabilises the aircraft close to the ground is bad! * We need to provide glider pilots with sensible, effective rules based on logic that allow the pilot to land first time, every time!! * Common sense has atlast prevailed, and the procedures reverted * The Base leg is just as busy for the inexperienced pilots. The list of tasks include: Assessing the angle immediately after the base leg turn (the most distant part of the circuit with the least options) Continuing to monitor Attitude, Airspeed, Angle and Lookout for the rest of the circuit Identifing the airbrakes and placing their hand on the blue lever Clearing other traffic for long finals and opposing base legs (Find conflicting traffic while you still have height and options) Re-fining the Aiming point to make it easily identifiable after the final turn Anticipating the final turn. * All of this list may not be specified in a checklist, but are actions that pilots will carry out. Experienced pilots will carry them out automatically almost sub-consicously, inexperienced pilots need to process each and every action. * At this point in a circuit, the glider is sinking into the turbulence from ground effect and visual illusions of the ground getting closer and the perspective of the horizion changing. I cannot understand some people insisting that our inexperienced or uncurrent pilots change the attitude and trim of the glider. >> My concern is that this might lead to inexperienced pilots doing just that >> rather than paying due attention to the wind sock and other indicators and >> adjusting their approach speed as dictated by the actual wind conditions. * Those 'inexperienced pilots' will have a far better chance of reading the wind sock before downwind then on late base. A lot of airfields have only one windsock, the lower you get, the less visible the windsock. I do not believe that many pilots will detect a 10 knot increase in wind speed during the botton half of a circuit, . Increased drift maybe, undershoot on the base leg maybe, 15 to 20kts of increase maybe >> Those who support the new teaching seem to be saying that one should pick >> the appropriate approach speed on FUST and then maintain this speed for the >> remainder of the flight. * This is not the new teaching, it is a return to an old proven way of bussiness. That is exactly the way approaches were/are taught. It provides a stable platform. There is nothing in the rules that prevents any pilot from increasing speed if conditions warrant. You have suggested that HELP (High Energy Landing Problems) are somehow connected to the 'Old' method of instructing. HELP is simply a lack of instructional standards when checking or supervising operations. Anybody who chews up half an airfield during a landing needs some re-training. There are no excuses, you simply must achieve the aiming point at the nominated speed. * The problem of pilots not predicting and allowing for weather contions will not be eradicated by lowering the energy level of the glider close to the ground and increasing the workload of the pilot. If a pilot gets into trouble on base, additional height needs to be burnt to accerate the glider to a safe speed. If that occurs while tracking direct for the airfield into wind, the effect of the wind gradient will multiple the height loss significantly. >> Despite all that has been said in this thread, I still prefer the "old" >> teaching. In my view, the best and safest technique is to pick up a safe >> speed near the ground of 1.5Vs on joining downwind and then, during the >> final stages of the downwind leg, confirm whether the actual wind is as >> expected and then increase speed accordingly on completion of the base turn. * How about so arguments based on logic and fact to backup your view? From: "Michael L. Texler" <[EMAIL PROTECTED]> > I used the words common practice intentionally, since there is the impression > that there are some who add 1/2 airspeed upon joining downwind (which is > counter to the instructors' handbook). > in my view flying a slower circuit then relying on memory to add the > additional speed on base when the student is under maximum load > adds additional risk > * Here, here! -- * You are subscribed to the aus-soaring mailing list. * To Unsubscribe: send email to [EMAIL PROTECTED] * with "unsubscribe aus-soaring" in the body of the message * or with "help" in the body of the message for more information. -- * You are subscribed to the aus-soaring mailing list. * To Unsubscribe: send email to [EMAIL PROTECTED] * with "unsubscribe aus-soaring" in the body of the message * or with "help" in the body of the message for more information.
