Flight Tech­nique/Three Im­pres­sive Turn­around Ma­neu­vers

Add some style to your rou­tine

Model Airplane News - - CONTENTS - By John Glezel­lis

Add some style to your rou­tine

For many, watching a pre­cise aer­o­batic rou­tine is al­most like watching an aerial bal­let, and to the aer­o­batic pilot, there is no feel­ing that is more grat­i­fy­ing than ex­e­cut­ing the per­fect flight. Fly­ing flaw­lessly boils down to hav­ing not only a prop­erly tuned air­craft but also a firm un­der­stand­ing of your own abil­ity as well as what’s re­quired for each in­di­vid­ual ma­neu­ver. Mas­ter­ing the var­i­ous ma­neu­vers is the first part, but there’s still an­other im­por­tant el­e­ment needed to de­velop a suc­cess­ful se­quence. By us­ing turn­around ma­neu­vers, you can stitch your moves to­gether so that the en­tire flight pre­sen­ta­tion is smooth and flow­ing. Choos­ing the right turn­around ma­neu­ver also helps you set up and plan the or­der of your flight seg­ments. Here are three ad­vanced turn­around ma­neu­vers that will add ex­cite­ment to your over­all aer­o­batic rou­tine.

HALF CUBAN-8

In­vented in the 1930s, the half Cuban-8 was first flown by Amer­i­can barn­stormer Len Povey. While at­tempt­ing a triple avalanche, his en­try speed was too high, so he de­cided to abort the at­tempt with a sim­ple half-roll on the back side of the fig­ure. Thus, the now-com­mon ma­neu­ver was born! To­day, the half Cuban-8 is pop­u­lar with the full-scale Red Bull Air Race and is used as a stan­dard turn­around ma­neu­ver.

OVER­VIEW

For the first few at­tempts, start at a gen­er­ous alti­tude for ad­di­tional safety. The tra­di­tional half Cuban-8 be­gins from up­right level flight par­al­lel with the run­way.

Pull 5/8 of a loop to es­tab­lish an in­verted 45-de­gree down­line with a brief line seg­ment as shown in the il­lus­tra­tion. Per­form a half-roll, and add a sec­ond line seg­ment (equal to the first). Fi­nally, pull the model into a 1/8 loop seg­ment, ex­it­ing the ma­neu­ver at the same

alti­tude as the en­try and trav­el­ing in the op­po­site di­rec­tion.

BY THE NUM­BERS

Step 1: In­crease throt­tle to about 85 to 100% power. Es­tab­lish the ma­neu­ver by gently pulling el­e­va­tor. The amount of el­e­va­tor used af­fects the over­all size of the in­side-loop por­tion. Us­ing a small amount of up-el­e­va­tor re­sults in a larger fig­ure, whereas us­ing more el­e­va­tor de­flec­tion will make the loop smaller. Step 2: As the model nears the top of the loop seg­ment, start de­creas­ing throt­tle to main­tain a con­stant flight speed. Once the in­verted 45-de­gree down­line is es­tab­lished, stop pulling el­e­va­tor. De­fine the 45-de­gree down­line by per­form­ing a brief line seg­ment, and take note of the line seg­ment’s length.

Step 3: Next, per­form a half-roll by ap­ply­ing aileron. Once the half-roll has been com­pleted, fly a sec­ond line seg­ment that’s equal to the first line’s length. Ap­ply cor­rec­tive in­puts as needed to keep the air­craft in the de­sired ori­en­ta­tion.

Step 4: Fi­nally, per­form a smooth 1/8 in­side loop to es­tab­lish an up­right-level exit. It is im­por­tant to note that the en­try and exit alti­tude should be the same.

VARI­A­TIONS

Like all aer­o­batic fig­ures, ma­neu­ver vari­a­tions are seem­ingly endless. In­stead of per­form­ing a sim­ple half-roll, you can ex­e­cute a full roll and then push a 1/8 out­side-loop seg­ment and exit in­verted. Rather than a con­tin­u­ous half-roll, you could also per­form he­si­ta­tion rolls (two points of a four-point roll, four points of an eight-point roll, etc.). Use your imag­i­na­tion. As with all ma­neu­vers, the tra­di­tional half Cuban-8 re­quires a cer­tain amount of time to mas­ter. It takes prac­tice to per­fect proper tech­niques.

TAIL­SLIDE

While it may seem sim­ple, the tra­di­tional tail­slide is one of the most chal­leng­ing ma­neu­vers to per­form prop­erly. At all times, you must ap­ply pre­cise con­trol in­puts and main­tain a cer­tain ori­en­ta­tion to en­sure that the air­craft falls backward. Ori­en­ta­tion of the model can often be­come dif­fi­cult, and the small­est head­ing de­vi­a­tion can re­sult in an un­suc­cess­ful at­tempt. Also, you have to re­mem­ber that, in a proper tail­slide, the con­trol in­puts are op­po­site com­pared to when the air­craft is in for­ward flight! Sim­ply said, there’s lots of “think” fly­ing go­ing on in the pilot’s head.

This is the “wheels-up” ver­sion of this ma­neu­ver. Breaking this ma­neu­ver down into four ba­sic steps will help ex­plain the var­i­ous in­puts re­quired, so let’s get started.

OVER­VIEW

Typ­i­cally, the ma­neu­ver is per­formed ei­ther to the left or right side of the aer­o­batic airspace. For a mid­size aer­o­bat, fly the ma­neu­ver at the end of the run­way so that you have a bet­ter vis­ual of the air­craft. For the first few at­tempts, per­form the ma­neu­ver about

200 feet away from your­self, into the wind and par­al­lel to the run­way.

Ini­ti­ate the ma­neu­ver by per­form­ing a grad­ual 90-de­gree pull to es­tab­lish a ver­ti­cal up­line. Af­ter a short line seg­ment for about five sec­onds, be­gin de­creas­ing power. As the air­craft nears a com­plete stop, ac­ti­vate the ap­pro­pri­ate flight mode and con­tinue to ap­ply the re­quired cor­rec­tive con­trol in­puts to main­tain a ver­ti­cal at­ti­tude. Re­mem­ber: If the air­plane is not com­pletely ver­ti­cal, it will not slide rear­ward. Once it is slid­ing back, ap­ply full down-el­e­va­tor and the model will fall with the wheels ori­ented to­ward the sky. At that point, re­lease the con­trol in­puts and re­turn the flight mode to the lowrate set­ting. A vis­i­ble “pen­du­lum” may be shown past the ver­ti­cal as the air­craft falls and es­tab­lishes the down­line, which is com­pletely nat­u­ral. Ap­ply down-el­e­va­tor, and exit the fig­ure in­verted at the same alti­tude as you be­gan the ma­neu­ver but trav­el­ing in the op­po­site di­rec­tion!

BY THE NUM­BERS

Step 1: En­ter the ma­neu­ver up­right and par­al­lel to the run­way, trav­el­ing into the wind. Ac­ti­vate the low-rate set­ting, and ap­ply 75 to 90% power. Gently ap­ply up­el­e­va­tor, and ex­e­cute a quar­ter­loop to es­tab­lish a ver­ti­cal up­line. Power set­tings will vary depend­ing on the air­plane you are fly­ing. Note the size of the ra­dius.

Step 2: When the de­sired alti­tude has al­most been reached, slowly de­crease throt­tle and ap­ply any cor­rec­tive con­trol in­put to keep the proper flight at­ti­tude to main­tain a per­fectly ver­ti­cal line. As the model be­gins to slow down, ac­ti­vate your 3D/tail­slide rate. I pre­fer to pull the throt­tle back so that there’s enough power to bring the air­craft to a mo­men­tary sta­tion­ary po­si­tion, then I pull the throt­tle to idle.

Step 3: As the air­plane be­gins to fall backward, ap­ply full downel­e­va­tor. This will cause the air­plane to fall in a wheels-up at­ti­tude. Dur­ing this “pen­du­lum” move­ment, slowly neu­tral­ize el­e­va­tor and re­turn to your “lowrate” set­ting.

Step 4: Per­form a 90-de­gree push (down-el­e­va­tor), and exit the ma­neu­ver in­verted at the same alti­tude in which you en­tered the ma­neu­ver. En­sure that the exit

IF YOU FIND THAT YOUR MODEL IS UN­ABLE TO FALL BACKWARD, EVEN AF­TER PROPER ORI­EN­TA­TION IS ES­TAB­LISHED, IT IS LIKELY THAT THE MODEL IS TOO NOSE-HEAVY.

ra­dius is the same size as the one per­formed dur­ing the en­try. To min­i­mize cor­rec­tions dur­ing a flight, you should al­ways take ad­van­tage of the var­i­ous ca­pa­bil­i­ties of your pro­gram­mable radio sys­tem. Fine-tune your air­craft to suit your per­sonal pref­er­ences, and make changes in small in­cre­ments un­til your model re­sponds smoothly to your con­trol in­puts. That’s it. Now fine­tune the setup of your plane, and fly the ma­neu­ver again! Prac­tice makes per­fect.

EXIT the ma­neu­ver at the same alti­tude and head­ing but in the op­po­site di­rec­tion as the en­try. EN­TER straight and level, straight into the wind.

Af­ter a short line seg­ment, ap­ply aileron to per­form a half roll. Af­ter the half roll is com­plete, con­tinue the down­line the same dis­tance as the in­verted line seg­ment just prior to the half roll. Then gently pull up-el­e­va­tor to re­turn to straight and level flight. Use enough power to main­tain a con­stant flight speed. Re­lease up-el­e­va­tor to es­tab­lish the in­verted 45-de­gree down­line. In­crease speed to 85 to 100 per­cent power, then gently pull back el­e­va­tor to es­tab­lish the be­gin­ning of the loop seg­ment of the ma­neu­ver.

EN­TER ma­neu­ver straight and level, trav­el­ing into the wind. EXIT ma­neu­ver at the same point and alti­tude as the en­try but trav­el­ing in­verted in the op­po­site di­rec­tion. Af­ter ex­tend­ing the up­line, throt­tle back and main­tain at­ti­tude and head­ing un­til the air­plane comes to a halt and be­gins to slide backward. In­crease power, and pull smoothly into a ver­ti­cal up­line. As the plane be­gins to fall backward, ap­ply full down-el­e­va­tor so that the plane falls in a wheels-up at­ti­tude. Once the plane has en­tered a ver­ti­cal down­line, neu­tral­ize the con­trols and ex­tend the down­line. Ap­ply some power and then push down-el­e­va­tor to es­tab­lish a 90-de­gree straight and level line while in­verted.

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