Exiting Spins on Heading & Pitch in an RV

[precession]

Tried posting this a few weeks ago, and for some reason it came out as a double post, which I tried to edit out. Trying again:

This is a question for you competition aerobatics guys. Exiting spins is one thing, and exiting spins properly in competition is another. In competition, you must (a) exit on the proper heading, and (b) draw a straight vertical down line (before recovering from the dive). The 2017 IAC Sportsman Sequence is calling for a 1 and 1/4 turn spin.

What exact sequence of controls are you using to accomplish both objectives in an RV? In particular, how far in advance of your exit heading are you applying opposite rudder, and when and how are you applying forward stick?

Currently I'm playing a guessing game in my -4 as to how much in advance of the desired exit heading to apply opposite rudder and it's not always working out. Obviously, it takes longer to stop a 2 or 3 rotation spin than a one rotation spin, and I get the impression RVs may not be as quick to respond to anti-spin inputs as pure competition aircraft, possibly due to smaller rudder size. I'm playing with using abrupt forward stick to lessen the rudder guessing game and force the aircraft to stop on the desired exit heading ... ?

Also, my -4 is still rather upright when it stops spinning, so to get a vertical down line I have to push hard into negative G. I spoke to an aerobatic competitor (non-RV guy) who said some competitors let the stick forward somewhat during the spin so they don't have to push so hard when the spin stops to get their vertical down line. Thoughts?

[Vern]

Easing the stick forward may accelerate your spin rotation rate.

[f14av8r]

I enter the spin with full pro-spin rudder and full aft and opposite stick. My -4 takes about 1/2 turn to recover from the barely developed spins used in competition. I recover from a 1 1/4 spin at 3/4 of a turn. I recover with full opposite rudder, neutral lateral and slightly forward stick. Then, once on heading, I use forward stick as necessary to get the pure vertical downline.

It takes some practice, especially on the Y axis recoveries since your sight picture clue for recovery at 3/4 turn will be on the Y axis as well.

Practice makes perfect.

[jrs14855]

Never spun an RV but in the popular aerobatic airplanes from the Pitts to the Sukhoi and many others: intentionally accelerate the spin almost immediately with forward stick, a bit of power, and a lot of inspin aileron.
Almost on the desired recovery point aggressive opposite rudder and more forward stick. After about 100 of these you should be able to blend the down line smoothly with the recovery.
the pitch attitude on recovery will be much closer to vertical.
Regarding outspin aileron, that is counterproductive and flattens the spin so the transition from recovery to vertical downline is a much greater pitch change. This usually looks really bad to the judges.
For a left rudder upright spin, right stick is outspin aileron, left stick is inspin aileron. Inverted spin stick position is opposite.
Upright spin: inspin aileron will usually pitch the nose down slightly and will always enhance the recovery.
Caution: this requires a LOT of practice. If you are uncertain of what the airplane is doing close the throttle and put the stick in neutral, full rudder opposite the rotation. This takes a lot of practice. The rate of rotation will increase dramatically depending on the amount of forward stick.
I learned this from a student after struggling with competition spin recovery for many years. Student could not land a Pitts but sure did nice competition spins.

[sandifer]

Jim well described the elevator/aileron technique which can clean up competition spins. The high performance monoplanes especially require this type of technique to get spins to look decent. Also useful in the Pitts, depending on a number of factors. I did not get far enough along with aerobatics as an RV pilot to provide info on how this works in RVs. Something to try as you gain experience.

Regarding the sequence of inputs and timing, I did a bunch of spins in my old RV-3 and an RV-6 w/ 7 fin, and never needed more than 1/4 turn to stop a spin in either direction, up to 3 turns. Those RVs I mentioned recovered a spin pretty much the same as my Pitts and most other aerobatic planes I've flown - full opposite rudder followed a fraction of a second later by a forward stick movement. I've never flown anything remotely aerobatic that required more than 1/4 turn to recover a competition style spin.

You'll need to figure out the amount of forward stick that works best for you, but slightly forward of neutral is pretty standard. Don't overdo the forward stick input. If you really overdo it, you can crossover which can be bad news for pilots who haven't received adequate training. Don't apply rudder and sit there waiting for any perceptible change in rotation rate before moving the stick forward. That will delay recovery. Move the stick very quickly behind the rudder input.

I never tried this in the RV, but most acro planes also recover more quickly and crisply if you apply full power simultaneously with the opposite rudder input. But first learn to stop the spin on heading with a precise vertical pitch/yaw attitude, then worry about power. In any case, be sure to get in the habit of applying full power ASAP as the spin stops to avoid wasting altitude. I know the RV is clean, but this still applies.

Regarding the hard push after a 1-turn spin, you can either blend the push into the recovery, or push vertical immediately after stopping the spin as long as you don't draw a perceptible line before pushing over. Some airplanes require care with the blended recovery to avoid the appearance of the airplane ceasing to autorotate (spin) about all 3-axes, which causes the judges to suspect the pilot is finishing on pure aileron. That will invite deductions. Also be aware that if you overdo the elevator and aileron technique for tightening/accelerating the spin, that the yaw/pitch moments become diminished. Be sure it still looks like a spin and not a spiral. Anyone familiar with the aileron roll rate of RVs will know the difference between an accelerated spin and a spiral, but some judges like to play dumb. They are looking for auto-rotation about all 3-axes. This last point is more related to snap rolls than spins, but worth noting IMO. Ground critiquing/coaching is required.

And remember that the 1-1/4 turn spin produces a natural yaw error that must be corrected simultaneously with the pitch error as the spin stops. You will need to re-apply a little rudder pressure in the direction you originally spun with. Just like the pitch correction, be sure to make the yaw correction before you draw a perceptible line upon stopping the spin or the judges will say you're "dragging a wing" (not perfectly vertical in yaw). Learn where your wingtip sits on the horizon when you're perfectly vertical in yaw, and always look to the side and check your attitude after each spin, as soon as it stops.

Practice is good, but practicing after getting some knowledgeable ground critiquing/coaching is much better. Good luck.

[jrs14855]

Lots of good advice from Sandifer. The more you accelerate the spin the less yaw error you will have at the 1/4 and 3/4 marks.
As far as power and speed control in many cases you will want to conserve altitude. Going to full throttle on recovery and keeping the down line short is the most efficient way of managing altitude. The vertical down line only needs to be identifiable, it does not need to be 500 feet long.
As you approach the target speed desired for the next maneuver pull to 4 G or so and you will be all set for the next maneuver. Experiment with what is best for your aircraft for the transition from vertical to level flight.

[ronschreck]

Excellent advice, all of the above.

While we are on the subject, spin entry is a subject that gets too little attention. Most RV pilots who are just starting aerobatic competition have grave concerns about staying in the aerobatic box. These concerns are valid as the RV can eat up real estate in a big hurry, so a poorly planned or executed sequence can easily exit the box several times during a flight. At the Sportsman level this is not the end of the world as the penalty for exiting the box is only 5 points. With a total possible point count of 1320 for the full sequence, 5 points is hardly a big deal! The rule of thumb is, never screw up a figure in order to avoid going out of the box. You will lose more points for botching the figure than you will lose for exiting the box.

One of the easiest ways to exit the box is to do a level flight spin entry, that is pulling the power to idle and maintaining level flight until the aircraft slows to stall speed. You can eat up a surprising amount of the box with this entry and even if you don't exit the box you will probably enter the spin not knowing where you are in the box as you have no way to see the box markers in level flight. The KNOWN Sportsman sequence will always have the spin entry after some maneuver that slows the aircraft and gains sufficient altitude to put you at or near the top of the box, such as an immelmann or a 45-degree up line. When you practice spins or when you design a FREE program for competition you should also precede your spin entry with a similar maneuver. Try it!

[Boyd Birchler]

Watch out on how abruptly you force the stick forward, for the vertical down line! An abrupt forward stick can easily transition the recovery into an inverted spin! This exact event caused a fatal accident in Pennsylvania 20 years ago. The pilot was practicing getting the vertical after stopping rotation, the plane transitioned into a inverted spin from which he was unable to recover.

An inverted spin from the pilots seat looks nearly the same as the upright spin, that is, unless you are looking right over the spinner instead of straight down at the ground. This pilot had never seen an inverted spin, much less a crossover spin from upright to inverted.

Yes spin training is expensive, but I urge you to go to someone who regularly teaches spins both upright, inverted and crossover, and get training! This is training that will keep you alive!

[sandifer]

To be clear, it's not so much how abruptly you unload the elevator during spin recovery that can cause a crossover, but in how far forward of neutral you move the elevator while you still have a rudder fully deflected. You can move the stick as fast as you want to a point just forward of neutral, and never come close to crossing over. Or you could move the stick more slowly, too far forward and cross over. You have to move it far enough forward to produce a negative spin. That's nearly fully forward with full rudder in most airplanes. Spins are typically recovered at idle and very low airspeed. It takes a lot of forward stick to produce an inverted spin from this condition. But airplanes vary, and there are lots of ways to screw up and aggravate a spin, so be mindful of the amount of forward stick you're applying.

Anyone doing spins should understand the potential for this to happen, and hopefully obtain advanced spin training as mentioned above. Don't underestimate the confusion and denial that can happen when something unexpected happens that you have not been trained on and never experienced. A Canadian Pitts S-1S pilot died a few years ago while practicing an Intermediate IAC sequence (not a rank newbie) after crossing over inverted after attempting to recover a 1-1/4 upright spin. Spun about 10 turns inverted before hitting the ground. Likely never knew what was happening. For anyone unfamiliar with crossovers, I shot this video a few years ago. You can see how cleanly a crossover to inverted can happen. The crossover from inverted back to upright was not as clean, but it's still quick enough to confuse someone who has not had training experience with this.

https://www.youtube.com/watch?v=i3DJlced8gw

[Canadian_JOY]

I have little to no interest in aerobatics, but decided to read this thread to gain some knowledge of spin recovery.

What I found here is a little slice of heaven.

The aerobatic community has a reputation for being tight-knit, extremely competitive, and also the kind of people who help each other out, to make each other the best they can be. This discussion thread is absolute confirmation that the acts of support between community members continues on, reinforcing the positive reputation this group has within the larger aviation community.

It sure is nice to see folks helping each other. What a wonderful breath of fresh air!