DAS

Cross-box Combos PHASE III Half Square 1/4 Loop 1/4

P Loop

S 1 U S . C S T H . R O / O C L F L I G H T

H-52 Cross-box Maneuver Combinations DAS

Theaerobatic box , outside of competition, is the reasonable airspace that a pilot performs his PHASE III maneuvers in with good visibility. Theperformance zone is the smaller airspace within the aerobatic box where the visibility and presentation is the best, but requiring that the maneuvers be performed closer together to stay within it. The advanced aerobatic pilot uses all the airspace within the performance zone by performing maneuvers parallel to both the X and Y axes. Maneuvering on the (cross-box) Y axis at the advanced level typically consists of performing two maneuvers to effect a turnaround at either end of the field, while at the same time repositioning the airplane toward the front or rear of the performance zone. The following pages contain some of the most complimentary maneuver combinations on the Y axis that also effect a turnaround.

Aerobatic Box X axis Y axis Mid-field

Center Box

Y axis Performance Zone X axis 1/4 1/4

Hammerhead

Humpty bump

Side note: The airplane’sflight path is judged R/C pilots who have not yet acquired the rudder in radio control , whereas the attitude knowhow to prevent wind drift. Students of X of the airplane is primarily judged in full-scale. Precision Aerobatics who know how to prevent Consequently, without being allowed to “crab” wind drift, can use the Y axis to make room for noticeably into a crosswind, a full-scale airplane certain maneuvers and to improve their viewing Loop Positioning center ends up drifting downwind while maneuvering. perspective. For example: To avoid having to box maneuvers Thus, a set of maneuvers on the Y axis are strain looking up, looping maneuvers are better Roll for better viewing designed into each competition sequence to viewed some distance out beyond the pilot, perspectives. re-position the plane to the upwind side of the whereas a slow roll is better viewed closer in. box. This practice will also prove helpful for

H-53 KPTR: Maneuvering on both the X and Y axes increases the room to maneuver while maintaining good visibility. Cross-boxTurnaround Combination: Humpty to a Hammerhead DAS

PHASE III

The Y axis turnaround combination of a humpty bump and hammerhead work well together, and are ideally suited to set up any center (aerobatic box) maneuver that requires a higher entry speed.

oetwo “one Each of these maneuvers favor high one” entry speeds Roll two “one and finish at high speed. Therefore, this combi- nation works equally well with the humpty bump before or after the hammerhead, and can be per- one two” formed to reposition the airplane either to the front or rear of the aerobatic boxC depending on which direction the plane is rolled in the first maneuver. 1/4

1/4 Roll Right 3 Half Pull-pull-pull humpty bump: Enter the humpty roll roll Left

3 Roll bump parallel with the runway.3 roll on the up- roll line in the direction that you want to fly across the box. Pull over the top, and perform a half roll on the downline to set up a cross-box pullout to level flight.

one”

Hammerhead: Perform the hammerhead with a 3 “one roll on the downline to exit heading back toward the center of the aerobatic box. Increase the throttle to build up sufficient airspeed for the next maneuver before or during the pullout, not after.

KPTR: The first in a series of maneuvers should set up the speed and altitude for the next. H-54 Cross-box Combination: Hammerhead to a Humpty DAS

PHASE III The Y axis turnround combination of a hammerhead followed by a humpty 1/4 bump makes quite an impression.

Hammerhead: Enter the hammer- one” Roll two “one head parallel with the runway. 1/4 Perform a3 roll on the downline to set up a cross- one” box pullout to Roll level two “one flight. One has the option to perform Pull-pull-pull humpty bump:¼ roll a3 roll on the upline of the on the upline in the direction that you hammerhead: Roll so that intend to pull over the top. In this the top of the plane is facing example, that will be to your left the front of the box for the Right 3 roll (toward the center of the aerobatic Left easiest perspective through Half 3 box). Pull over the top, and perform roll roll the remainder of the upline a half roll on the downline to exit and the pivot. heading back toward the center of the box. Option

Note: Establishing level flight be- 1/4 tween maneuvers provides a moment

“one Roll one two” of respite to begin anticipating what 1/4 is next and to ensure that the wings are levelC along with being an impor- tant competition requirement and a stamp of proficiency.

KPTR: A proficient pilot establishes a definite level H-55 end to the first maneuver before entering the next. Cross-box Combination: Pull Humpty to a Push Humpty DAS

Back-to-back humpty bumps PHASE III on the Y axis work well to- gether, and are made more interesting by pulling over 1/4 the top of the first humpty, and pushing over the top of 1/4 the second.

Pull-pull-pull humpty bump: one” Roll two “one 3 roll on the upline in the direction that you want to fly across the box. Pull over one two” Note: If considerable rudder the top with right rudder. is applied trying to correct a Perform a half roll on the deviation from vertical at the downline to set up a cross- point of initiating the pull box pullout to level flight. or push over the top, that Half Left Right roll 3 roll rudder will likely have to 3Roll roll Pull-push -pull humpty:3 - be maintained and will take roll the airplane into position precedent over the usual to push over the top toward P-factor rudder corrections. the center of the box. Push I.e., “pull-right. -- - push-left”. over the top with left rudder, at slower speeds only works and hold the downline for a

on a consistent basis when “one Roll one two”

few counts before pulling out. “one the pull or push starts with the wings level after a truly vertical upline.

KPTR: Anticipating which way to roll and push or pull stems from routine wings level entries and perfect verticals. H-56 Half Square Loop Setup to a DAS

The following page contains a Y axis turnaround combination requiring PHASE III a higher altitude setup to a spin. Every aerobatic pilot should be familiar with using the Immelmann turnaround to gain altitude. The turnaround that To spin advanced pilots use to more precisely control just how much altitude is gained is the half square loop.

Note: While a spin can be set up in any direction, it is much easier to keep within the performance zone when set upinto the wind. Therefore, the half square loop turnaround should be performed downwind of center box.

Half square loop 1. Approach the entry at high speed, full power, with the wings perfectly level. Pulling to the upline should be smooth, but completed quickly, in order to minimize the chance of a deviation occurring during the pull.

You also have the option to 2. Maintain full power to improve controllability and tracking once you perform a half roll on the get to the top. And unless there is a strong contrary crosswind, look for upline of a half square loop, and expect to need increasing amounts of right rudder at some point and then push to upright along the upline to counter the increasing effects of slipstream. flight. 3. Approaching the targeted altitude, assuming the upline is truly vertical, “one two three four” smoothly pull elevator with increased right rudder to cap off at the top Option inverted. One can then maintain inverted flight to set up an inverted spin, or roll upright to set up an upright spin.

Side note: With all the twisting and turning going on at this point, should there be any question about the direction to apply the rudder when a devia- tion from vertical is first detected, knowledge of the increasing effects of slipstream along an upline should provide assurance that right rudder will correct it. However, keep the rudder input initially small and watch the plane closely, just in case it has to be switched for whatever reason. (FYI: The battle to correct the upline after it was entered without level wings will be greater than battling a 20 mph direct crosswind!)

H-57 KPTR: Counting on the upline will help you consistently match the right altitude to the number of spin revolutions that will follow. Cross-box Combination: Upright Spin to a Hammerhead DAS

A popular Y axis turnaround combination is the PHASE III 13 -turn upright spin followed by a hammerhead. Here, a 23 -turn spin is performed to afford the pilot a little more time to anticipate the spin’s Left upright spin cross-box recovery.

A23 -turn spin set up parallel with the runway will exit cross-box in the same direction the spin was initiated (into the wind typically). You

oetwo “one “one” should avoid initiating a spinwith the wind, since the wind will displace the entry and cause it to 1/4 1/4 appear barrel-rolled or prematurelyforced! If there Cross-box is no crosswind component to the wind, one’s only concern is to initiate the spin in the direction that you want to be heading after the spin. “two” As you sense the about to break, sneak in a Side comment: It is because the vast (neutral)

Roll little rudder in the direction that you intend to spin Right majority of R/C flyers recover from 3 roll to ensure the spin breaks that way. Once you their spins in whatever direction the input the spin, keep track of the revolutions from airplane happens to be heading that the beginning, and quickly neutralize the controls few things are as impressive as when on “two,” in order to stop spinning at 23 . a pilot enters a spin in one direction, recovers in another, and then validates

Immediately after the spin stops, push to a perfect one” that it was no accident by performing vertical downline, square the wings if necessary, another ! andstart applying power to build up airspeed for the hammerhead. Due to the lower airspeed exiting a spin, keep the next maneuver simple (no rolls on the upline). 3 roll on the downline after the pivot to exit heading back toward center box.

KPTR: As a rule, given the choice to spin left or right, choose the direction that is more into the wind. H-58 Cross-box Combination: Bridge to an Upright Spin DAS

An example of efficiency and proficiency using Stall PHASE III one maneuver to set up the next is performing a cross-box bridge to achieve the altitude for a spin, while also decelerating close the stall speed so that a spin can be entered on theYaxis without needing a lengthy setup. “one” Side note: Consistently enter- Cross-box bridge spin entry: Enter the bridge ing maneuvers with the wings parallel with the runway. Set the upline, and level and attention to using the 3 roll the airplane into position to (push) cap off same inputs usually leads to at the top upright (into the wind typically). quickly noticing any additional Maintain an even count along the upline to corrections that haven’t been achieve sufficient altitude to perform the spin. “two” covered here, but turn out to be This practice then reinforces correctly matching needed in practice. One such the altitude gained to the general number of spin example can occur flying a revolutions that you intend to do, e.g., a longer high power airplane turning a very large propeller: A more count sets up a higher altitude spin entry and Right more revolutions. Neutral aggressive pull to the vertical 3 roll “three” can produce so much P-factor Upright spin: Once you have initiated the spin, effect that the plane turns a start counting the revolutions when the top of little to the left, despite the the plane faces the direction that you intend to higher airspeed. Obviously, a recover, and neutralize the controls just before little right rudder during the achieving the number that you want to stop on. pull will correct this until the two three upline is set, at which point no

“one Roll one two ” Note that while a bridge or half square loop setup more rudder should be required to a spin may make it possible to do several revo- until slipstream begins to take lutions, it is more dynamic to perform fewer over as the airplane slows on revolutions in order to demonstrate a perfect the upline. vertical downline afterC versus spinning until altitude forces a rushed pullout.

H-59 KPTR: A bridge is a great way to quickly gain altitude to set up a spin at the upwind end of the field. P Loop Turnarounds DAS

An advanced turnaround maneuver that is seldom seen outside of aerobatic competition, but that PHASE III offers more versatility than just about any other maneuver, and is also a lot of fun to fly, is theP loop .

The P loop turnaround P loop with a half roll on the downline after a: loop sets up a lower entry into the next maneuver. or P LOOP Crosswind or The P loop turnaround Crosswind with a half roll on the Use right rudder over the : slower top of the loop to upline before a loop sets up a higher entry oetwo “one correct P-factor and - stream. Unless, rudder into the next maneuver. into a strong crosswind

RUDDER

Slipstream

is required. one two”

Use right rudder to correct HalfRoll NOTICE: All that can be said about the proper Half slipstream as the airplane rollRoll roll uses of rudder to prevent crosswind drift during slows along the upline, and loops (and for that matter, keeping loops round) increase the right rudder to has been said inPrecision Aerobatics , and correct P-factor and slip- therefore will not be repeated again here. Let it stream looping over the top. just be said, for the sake of those who have Unless, rudder into a strong one” skipped that phase of learning, look for the left- crosswind is required.

turning tendencies of slipstream and P-factor “one to require right rudder corrections during the slower phases of maneuvers. Yet, at a certain strength, crosswinds become the dominant force requiring rudder correction, particularly over the

slower tops of loops. Knowing what to look for Reverse P loop and experience will tell.

P LOOP

KPTR: The ease of the next maneuver will directly reflect whether the P loop was kept vertical. H-60 Cross-box Turnaround Combination: DAS P Loop to a Humpty Bump or Hammerhead

PHASE III Reduce power Performing a P loop followed by a humpty bump or hammerhead on the Y axis combines an awe- some display of aerobatic skill and flying as a stylistic art form!

P loop:

oetwo “one

oetoRl one” Roll two “one Approach the entry from a medium alti- tude, parallel with

one two” the runway, at high 1/4 speed, wings level.

Cross-box

1/4 Roll Half Left Left 3 roll 3 Smoothly (not gradually) roll Roll roll input and hold a fixed ele- Note: Anytime a refinement like vator amount to initiate a constant radius loop. rudder is needed, remember that if you do not input enough, you Relax the elevator slightly will still improve the maneuver. one” tofloat over the top of the On the other hand, continuing to “one loop and keep it round. increase the rudder until its effect is obvious, can turn an acceptable Reduce power and set maneuver into a sloppy mess. the downline. If in doubt, input less, rather than more. 3 roll on the downline to set up a cross-box pullout to level flight....

H-61 KPTR: (With the exception of correcting vertical snap rolls) it is better to err on the side of not enough rudder than to over-control!