There are many good reasons to learn to fly advanced aerobatics, but the most compelling is the personal satisfaction that always comes from overcoming each maneuver’s particular challenges. If you’re like most aerobatic pilots, your initial learning curve was steep through basic looping and rolling maneuvers, but it went flat relatively quickly with stick time alone. That’s because to be successful at advanced aerobatics, you must firmly grasp the steps involved during each maneuver before taking to the air (as opposed to burning a lot of fuel and hoping for the best). The good news is that advanced aerobatics can be done by anyone who is proficient at basic aerobatics and has a desire to learn. With that foundation and a little guidance, you can progress beyond the basics into snappier aerobatics and vertical maneuvers.
HAMMERHEAD WITH VERTICAL ROLL
Once you have become proficient at the basic hammerhead, adding a roll to the up-line is a fairly simple process, but maintaining a perfect vertical line before and after the roll is what makes this maneuver truly awesome.
You’ll need to approach the entry at a higher speed and deliberately pull up with the wings perfectly level. (If the wings aren’t level, the upline will not start out vertical and will probably doom the attempt to failure.) As you’ll discover, the only effective way to overcome a poor upline is to concentrate on pulling to the vertical with the wings level next time! You’ll also need to quickly neutralize the elevator at the proper time to nail the upline and establish the plane’s inertia straight up. To be certain that the upline is truly vertical, hold it for at least a count of “1,000” before performing the roll with full aileron. If you rush into the roll without defining at least a short vertical line, your attempts will tend to vary greatly. If you wait too long or “hunt” for the vertical line, you may not be able to finish the roll before wind and/or propwash skews the airplane from vertical. A count of “1,000” should be sufficient to avoid these common faults.
Due to the compound effect a deviation has on subsequent stages of a maneuver, when the upline is not vertical and/or you are involved in making corrections to fix the upline, you should skip the roll and probably bail out of the maneuver altogether. If, however, you need to hold in some rudder to correct for the propeller slipstream or wind, neutralize the rudder immediately before initiating the roll and then resume it again immediately after the roll. Holding in the rudder during the roll would likely cause the plane to corkscrew and deviate from vertical.
As a consequence of maintaining a great upline before, during, and after the roll, performing a good hammerhead is almost certain: reduce power while continuing to maintain a perfect vertical line until the plane stops climbing, then initiate the pivot with full rudder, etc.
VERTICAL SNAP ROLL
BUILDING A VERTICAL SNAP ROLL CORRECTION
The pilot who is able to perform a vertical snap roll and maintain a perfect vertical line afterward is, frankly, an elite flier! Those who rely on huge control throws and power to rescue their maneuvers will find them of no help here. You could say that a snap roll on the upline to a hammerhead is one of the top five signature maneuvers performed by truly advanced aerobatic pilots. I’ve found that the vertical snap roll is learned most quickly by pilots who are proficient at their uplines, acquire a good understanding of what is involved beforehand, and use a building-block practice method.
The faster the airplane is flying after the snap roll, the easier it will be to keep the plane truly vertical. Therefore, approach the entry with considerable power and speed. You’ll need to quickly set the upline for a count of “1,000” and then input a left snap roll before losing much speed. A left snap roll is recommended because it starts and is completed quicker than a right, so there’s less time for deviations to worsen.
During a left snap, the airplane will pitch and yaw considerably toward the canopy and to the left before it reaches critical angle of attack and starts snapping. Because of this, you’ll need to input opposite right rudder and forward elevator immediately after the snap to correct the deviations that took place at the start of the snap. The amounts required will have to be determined in practice. Focus on the rudder correction input first by committing to a specific amount, e.g., Ω inch, and then target different amounts until you find what works best. Then do the same with the forward elevator. Of course, this is moot if you’re thinking so much about the correction after the snap that you end up under- or over-rotating the snap itself. Prioritize stopping the snap at the proper time, and then learn to correct the line afterward.
I first teach pilots to neutralize the controls to stop the snap precisely, pause for half a second, and then correct the upline. As the pilot’s awareness and accuracy increases, stopping the snap and correcting the upline occur simultaneously by quickly returning the rudder and elevator through neutral into opposite rudder and forward elevator.
A very common fault is over-controlling the correction because the pilot wants to see his inputs doing something. The correction inputs after the snap should be enough to establish a perfect vertical upline. Visible yaw and pitch is not the object. Our only concern is repeating the rudder and elevator inputs that continually produce the best outcome. Committing to the inputs, versus merely reacting to the plane, is the quickest way to develop the physical muscle memory that will enable you to eventually perform single snap rolls without thinking.
When you’ve stopped the snap, you’ll need to lessen the right rudder correction and continue fine-tuning the rudder to counter the left turning effects of the propeller slipstream or wind on the upline.
ROLLS AND SNAPS ON DOWNLINES
One advantage of performing rolls on up-lines is that the uplines become extended and thus there’s more altitude and time to add rolls or snaps to the downline. Since the plane enters the downline after the hammerhead with almost no airspeed, idling the engine is usually optional, but if you add rolls to the downline, it becomes important to idle the engine after the pivot to buy a little more time coming down. After establishing the downline, perform the roll with full aileron to complete the roll before using up too much altitude and, if any rudder is being used prior to the roll, it will have to be neutralized before initiating the roll for the roll to remain axial.
Maintaining a perfect vertical downline after the roll is the most distinguishing and dynamic feature of this maneuver at the advanced level. Many pilots will prematurely “cheat the pull” or “short the line” after the roll due to fear of running out of altitude. When this occurs, shorten the downline before the roll to create more time to display a definite downline after the roll-before pulling out. Or, extend the upline before the pivot to buy more height and therefore time coming down.
Note that because the wing is stalled during the snap, it takes a moment longer for the plane to stop snapping after the controls have been neutralized. Therefore, try to neutralize the controls a split second before one complete snap. The good news is that gravity is helping the snap remain on line, compared to the upline where gravity is trying to tug the airplane away from vertical. If the airplane does deviate from the downline, it will most likely pitch toward the canopy, requiring a little forward elevator pressure after the snap to push the nose straight down again.
During spins from unconventional entries, begin counting the revolutions when the top of the plane faces the direction that you want to be heading when you finish spinning. Now, if you really want your sense of satisfaction to soar, not to mention your reputation, add a roll or snap roll on the upline, then perform a hammerhead into a spin. Won’t that look cool?
It’s very easy to get ahead of yourself, thinking about the roll elements and end up overlooking the base elements that everything hinges on. So remember, whenever your attempts at vertical maneuvers fail, it will almost always be the result of not establishing and maintaining perfect vertical lines before and after the roll element, so continue emphasizing good uplines as your number one priority even when other elements are added to them. Good luck!