{"id":3775,"date":"2016-03-25T06:06:49","date_gmt":"2016-03-25T13:06:49","guid":{"rendered":"http:\/\/tailwheelersjournal.mechadigital.net\/?p=3775"},"modified":"2021-08-26T20:37:55","modified_gmt":"2021-08-26T20:37:55","slug":"the-yoyo","status":"publish","type":"post","link":"https:\/\/tailwheelersjournal.com\/the-yoyo\/","title":{"rendered":"# 151 The YoYo"},"content":{"rendered":"

If the Accelerometer is the Rodney Dangerfield of instruments, perhaps it\u2019s because \u201cG\u201d force is the Rodney Dangerfield of forces.\u00a0 Hell, it\u2019s not even included in the \u201cfour forces\u201d.\u00a0 But it should be, perhaps as a sub-force of gravity. \u00a0“G” force is nothing more than the force caused by acceleration or change of direction.\u00a0 It can be felt by us or indicated by an instrument like the “G” meter. \u00a0“G” force has some effects other than making centrifuge pilots pass out and passengers to throw up.\u00a0 The Yo Yo is a maneuver designed to help us learn how to feel a specific amount of “G” force.\u00a0 Think of it as a butt-calibrator.<\/h3>\n

<\/h3>\n

Let\u2019s take one of the sacred mantras repeated by virtually every flight instructor at some point.\u00a0 They will tell you that in a 60 degree level banked turn, the stalling speed will increase by about 40 percent and the airplane will experience 2 “G”s.\u00a0 They are correct.\u00a0 BUT, the average pilot soon forgets part of that truism.\u00a0 He forgets the part that says \u201clevel\u201d.<\/h3>\n

<\/h3>\n

Everyone knows that lift is the force which makes an airplane turn, but in order for it to turn, we must borrow some of its vertical component.\u00a0 That\u2019s why the nose drops\u00a0when we bank\u2026the vertical component of lift is diminishing.\u00a0 And, you see, in order to maintain the starting altitude, the elevator must be deflected in order to keep the airplane\u2019s nose from dropping.\u00a0 And in order to maintain that attitude which will result in a level turn, the airplane will experience positive “G” force.\u00a0 Here comes the part they never tell you.\u00a0 And I\u2019m afraid that in some cases the reason they don\u2019t tell you this is because they don\u2019t know!\u00a0 The fact is that it is “G” force which increases stall speed,<\/strong> not angle of bank.\u00a0 After the usual test of stalling with a steep bank, simply allow the altitude to decrease instead of hauling back on the elevator. \u00a0That\u2019ll keep \u201cG\u201d force from increasing with an increase in stall speed.\u00a0 \u00a0That\u2019s why we teach pilots at tailwheel town to stop trying to climb during that initial turn after takeoff.<\/h3>\n

<\/h3>\n
\"140
The 140, pulling 1 G.<\/figcaption><\/figure>\n

If there is one thing that truly separates the way flying is taught at Tailwheel Town and the way it is taught at Acme, it\u2019s the way we use maneuvers.\u00a0 Critical to the philosophy of learning here is that for every skill we want to teach, there is a maneuver which can, through practice, make that skill easier and more logical to learn.\u00a0 And so we have \u201cThe Yo Yo\u201d.\u00a0 With the exception of the steep<\/h3>\n
\"BW-inverted\"
Bill Warren pulling 1 G.<\/figcaption><\/figure>\n

turn, most fliers rarely have a chance to play with “G” force.\u00a0 Why limit that experience to providing zero “G” to your dog or some giggling little kid (little kids LOVE zero “G”)? \u00a0The Yo Yo provides a way to experience “G” force and more than simply experiencing it, you\u2019ll learn to recognize a couple of conditions.\u00a0 They are .5 “G” and 2.5 “G”.\u00a0 These two landmarks have been chosen for a reason.\u00a0 If we actually push to zero “G”, we will not only cause everything on the dashboard to float.\u00a0 We will also cause the oil to flow out of the crankcase through the breather, and the carburetor float to lose its reason for being and your engine will quit..\u00a0 That\u2019s kinda bad for engines and it makes a big mess that someone has to clean up.\u00a0 But by limiting the lower side to .5, we can come really close to zero, keep the engine running and the oil where we added it.\u00a0 On the other side, by limiting the positive pull to 2.5 “G”, we give ourselves a cushion and pretty much guarantee that we won\u2019t see the \u201cwing-off\u201d light begin to flicker.<\/h3>\n
\"G
The G meter with its telltales resting on 5+ and 1.5-. Its active needle is resting on slightly more than 1 G. That needle will move with every little change in G force, while the telltales will stay at their max and min indications.<\/figcaption><\/figure>\n

We can\u2019t perform the Yo Yo in an airplane without a \u201cG\u201d meter. I carry a portable one in my flight bag. I find it interesting how few fliers are familiar with it.\u00a0 That may be because it is normally not found in any of the airplanes they fly.\u00a0 It should be.\u00a0 One of the ways in which I tell if a flier knows about the instrument is how they deal with it on the pre-takeoff checklist.\u00a0 The \u201cG\u201d meter\u2019s \u201ctell-tales\u201d are zeroed by simply pushing the reset knob.\u00a0 Those not familiar with it will attempt to turn the knob as if it\u2019s like a Kollsman knob on an altimeter.\u00a0 They will also remark that there must be something wrong with it because it\u2019s on \u201cone\u201d instead of \u201czero\u201d.\u00a0 I patiently point out to them that if it were on zero, we\u2019d be floating in the cockpit, since we normally have one \u201cG\u201d on us when at rest.<\/h3>\n

<\/h3>\n

Now one of the things that every pilot should know is that for every airspeed there is an amount of \u00a0\u201cG available\u201d.\u00a0 You might try to pull more “G”s than that, but you won\u2019t have much luck\u2026 the airplane will stall before you reach it if your speed is not high enough.\u00a0 That\u2019s why aeronautical engineers specify a maneuvering speed, or VA for every airplane produced.\u00a0 So to make sure that there is a sufficient “G” available, we\u2019ll set an airspeed range for this maneuver.\u00a0 That speed range will vary with aircraft model, so I\u2019ll be a bit vague about it in this little description of this maneuver.<\/h3>\n

\u00a0Here\u2019s how the maneuver works: In flight, initially we\u2019ll lower the nose and allow the speed to increase.\u00a0 When it reaches an airspeed that will provide the “G” available of well over 2.5, we\u2019ll pull and watch the “G” meter.\u00a0 We\u2019ll stop our pull at 2.5 and we\u2019ll note what it felt like in the seat of our pants.\u00a0 Right now the nose is up and the speed is decaying.\u00a0 So we\u2019ll now push and once more we will watch the “G” meter.\u00a0 We\u2019ll stop the push at .5, hold that pitch attitude and allow the airplane to accelerate.\u00a0 When it reaches that aerobatic entry speed that we previously decided on, we\u2019ll pull and<\/h3>\n
\"IMG_1323\"
The 140 pulling a couple of positive Gs in a pull.<\/figcaption><\/figure>\n

repeat the process. \u00a0Just a word about those \u201ctell-tales\u201d. \u00a0\u00a0Every “G” meter has \u201ctell tales\u201d.\u00a0 These are needles that only increase and stay at the maximum they\u2019ve reached.\u00a0 The center dial remains \u201calive\u201d, indicating what we\u2019re pulling at every moment.\u00a0 Once we\u2019ve established a range and rhythm, we\u2019ll simply keep pulling and pushing, accelerating and decelerating while we peg the max negative of .5 and the max positive of 2.5 “G”.\u00a0 And we\u2019ll find that we are \u00a0maintaining a pitch attitude no higher than 45 degrees up and no lower than 45 degrees down.<\/h3>\n

<\/h3>\n

As a flight instructor, I supervise this rhythmic maneuver until I think the student has<\/h3>\n
\"DSCN3091\"
Tara notices the “Wing-off” light, flickering.<\/figcaption><\/figure>\n

educated the seat of his pants.\u00a0 Then I simply zero the tell tales and place my hand over the “G” meter so he can\u2019t see it.\u00a0 I allow the applicant to zoom to one more cycle, then I remove my hand, exposing the tell tales.\u00a0 They should be at .5 and 2.5 “G”s.\u00a0 And the flyer used the seat of his pants to set those values, because now he knows how they feel.<\/h3>\n

Mission accomplished.<\/h3>\n","protected":false},"excerpt":{"rendered":"

“If the Accelerometer is the Rodney Dangerfield of instruments, perhaps it\u2019s because \u201cG\u201d force is the Rodney Dangerfield of forces.”<\/p>\n","protected":false},"author":3,"featured_media":3779,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[3],"tags":[14,35,67,75,165,178],"_links":{"self":[{"href":"https:\/\/tailwheelersjournal.com\/wp-json\/wp\/v2\/posts\/3775"}],"collection":[{"href":"https:\/\/tailwheelersjournal.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tailwheelersjournal.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tailwheelersjournal.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/tailwheelersjournal.com\/wp-json\/wp\/v2\/comments?post=3775"}],"version-history":[{"count":0,"href":"https:\/\/tailwheelersjournal.com\/wp-json\/wp\/v2\/posts\/3775\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/tailwheelersjournal.com\/wp-json\/wp\/v2\/media\/3779"}],"wp:attachment":[{"href":"https:\/\/tailwheelersjournal.com\/wp-json\/wp\/v2\/media?parent=3775"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tailwheelersjournal.com\/wp-json\/wp\/v2\/categories?post=3775"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tailwheelersjournal.com\/wp-json\/wp\/v2\/tags?post=3775"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}