Authored by Dan Knippen
Hope everyone is enjoying our flying season so far. As I’m writing this in early April the wind and weather, as a whole, has not been very nice to us. Up to this point I have had only one good day to fly the new Edge. I was a basket case for two days prior to the test flight. Before flying your new bird always have qualified people help you range check and make sure everything is going in the right direction. No matter how long you have been flying, a second or third opinion can really save the day. I should know!
Now that the Basic sequence has been completed, its now time to move on and try something a little more difficult and challenging. Not long after I soloed and became a little more confident with my flying, I took an interest in aerobatic flying. I can remember Bob Carroll with his pattern ship, and Ray Tinley flying a Great Planes Cap 21. One of the first things I wanted to know was how do they do those snap rolls? Much to my delight the snap rolls I did (left only) with my trusty Great Planes trainer 40 weren’t pretty but could be done. So this month I would like to cover positive left and right snap rolls as well as negative left and right snaps.
Because a snap roll happens so quickly, it’s often very difficult to observe when judging. These different snap rolls will surely get you a zero if not done properly. From what I’ve learned after attending judging schools and flying the maneuvers is that the snap roll is a fairly high speed stall maneuver with induced auto rotation. There are two things to determine that a positive snap has occurred. First the nose of the plane must move away from the wheels and depart the flight path, and then auto rotation must be initiated. If either of these do not occur a zero must be given.
Where do the sticks go when performing a snap roll? You should know that there are a few different ways to perform a left positive snap for different situations but to keep it simple I’ll explain the standard way most people do this maneuver.
Begin at a safe altitude with wings level and about half throttle and flying from left to right. When the plane gets in front of you, move both left and right sticks at the same time. Apply left (rudder) stick straight left and the right stick (elevator and aileron) straight back and to the left corner. The nose will come up and then the plane will auto rotate to the left 360 degrees and stop upright (hopefully, after you release the sticks LCC) and at the same altitude with no under or over rotation. No problem! You will need to practice this maneuver many times to get the timing down as well as snapping at different throttle positions. Some planes do not snap well or will not stop when you want them to for some reasons due to design or weight. I recall Bob Carroll had (R. I. P.) one of the first Hanger 9 Extra ARFs when they first came out. The wings were a little heavy, and no matter what Bob tried, his plane would either stop short of completing the snap or over rotate just a little, and sometimes a lot. If you under or over rotate 90 degrees with any snap roll it will be a zero for that maneuver. I would recommend you practice just as many right snaps as left. To be good pilots you need a good plane that will do snap rolls in both directions.
Stick position for the right positive snap is similar. Left stick (throttle at about half) will go straight right. The right stick (elevator and aileron) at the same time will move straight back and then to the right corner.
Then there are the negative left and right snap rolls. The criteria for these snap rolls are the same as positive snaps except with a negative snap the nose will break away and move towards the wheels as the plane departs the flight path.
Stick movements will be as follows. For a left negative snap, right stick moves towards the left top corner. At the same time the left stick moves straight right. For a right negative snap move the right stick to the top right corner, and the left stick straight left. Enough of this stuff, let’s fly!
When you’re doing snap rolls on a vertical or 45 degree up line the same procedures apply, only don’t forget full throttle must be maintained or your plane will quickly lose all airspeed. Especially those 46 % jobs sporting very thick airfoils. On your down lines you want the throttle at full idle until you finish the maneuver. One other thing you want to do when snapping on a horizontal line is finish the snap at the same altitude as you started. On vertical upline snaps, because of the auto rotation, your plane will end up offset to the left or right from the original upline. This is ok and no down grade should be given as long as you can still maintain the vertical line. If you don’t end up a little offset you didn’t do a snap. ZERO! Same rule applies for down line snaps.
Here is an example of how a Judge would score a snap roll on the down line. Starting with a score of 10, you perform a perfect down line positive snap roll with a little offset. But instead of keeping the down line straight your down line is at about 60 degrees instead of 90 degrees. Your 10 now just became a 7. With 30 degrees off, a one point deduction will be given for every 10 degrees off. Until next month!
See you at the field