The Perfect Stall Turn (Or For The Yanks, The Perfect Hammerhead)

Pilots In Trouble – Because They Limit Their Training, Their Aircraft And Their Thinking

World record aviator Steve Fossett is most certainly dead. He disappeared on Monday, September 3, 2007 while flying a Super Decathlon aircraft in Nevada. Although no one knows what happened, one possibility is that Fossett found himself in some of the rugged terrain that Nevada is famous for and crashed while trying to turn around in a box (dead end) canyon.

IF that is what happened to Fossett, he wouldn’t be the first. Over the years, many pilots have died needlessly when they found themselves flying into terrain where they lacked the power to climb or the room to turn around.

About a year ago, on October 11, 2006, New York Yankees pitcher Clyde Lidle was killed in New York City when his Cirrus aircraft crashed into a highrise apartment building. Lidle and a flight instructor got themselves into trouble when they flew into a narrowing channel formed by buildings on either side until they lacked the room to turn around.

According to the National Transportation Safety Board investigation, Lidle’s aircraft would have had to turn aggressively at a 53 degree angle of bank to successfully make a 180 degree turn, but he or the instructor failed to initiate the turn soon enough or to make it steep enough. Both died.

Think Vertical

The training manuals say that like so many pilots in similar situations, Lidle and his flight instructor failed to plan their route properly and account for terrain and wind. That is true.

But then the training manuals tell a lie. They say that once the decision is made to fly into the narrowing corridor or box canyon, the pilot is dead.

Not so.

By executing a maneuver called a Stall Turn (or Hammerhead Turn in American), Lidle and his instructor would most likely be alive. A second option would have been a Box Canyon Turn, which is preferred by mountain flying instructors. Although it takes more room to perform, a box canyon turn is more likely to be of use because it is easier to teach to newer pilots and requires less initial airspeed than a hammerhead.

We might discuss the Box Canyon Turn in another installment, but for today your Uncle Robert will teach you how to do the perfect Hammerhead. I’ll use the word “Hammerhead” in homage to an American who is the absolute master of the hammerhead: Patty Wagstaff. Patty lives in St. Augustine, Florida – but she might have been seen once or twice in Holetown (or so I’m told. Hi Patty!) 😉

What Is A Hammerhead Turn?

Simply put, an aircraft doing a hammerhead turn starts from level flight, pulls straight up to the vertical (going straight up) and then when almost out of airspeed, pivots left or right 180 degrees to descend vertically along the same path as its vertical climb. On the pullout, the aircraft resumes level flight going back the way it came.

Here’s an animated GIF of a hammerhead done to the right. I hope it works for you.

The Perfect Hammerhead

Uncle Robert is not going to lecture all you pilots out there about using an aerobatics-certified aircraft, wearing a chute, filing your flight plan and going to an area without traffic or restrictions. You should know enough to do that on your own – but you also know that there are probably thousands of 45-hour-wonders who have looped or rolled a Cessna 152 without all of the above.

You will make up your own mind, and no, I wasn’t wearing a chute or flying a Pitts Special when I did my first hammerhead. I was all alone in an old Super Cub after reading a “basic aerobatics” manual. I don’t advise it, but for me everything I’d heard about the Lord looking after children and idiots was true. Once again, I don’t advise that you follow my poor example.

Enough of the lecturing – on to the Hammerhead.

We’re going to do this hammerhead in a Cessna 172.

“Horrors!” you say, “The 172 is a four place underpowered passenger aircraft that isn’t certified for aerobatics.”

Precisely. And that is why were going to hammerhead this aircraft – because when you need to do a hammerhead to save your soul, you won’t be flying a bull Stearman. You’ll be flying something like your 172. We’re also going to do this from level flight and a slow cruise – without a dive to pickup the airspeed – just where you would be if you found yourself in trouble.

Start With A Slow Cruise

Call it 2300 rpm on the tach, three-quarters fuel load with two big guys in the front and a girlfriend in the back. Yes, that’s right – we’re probably over gross and wallowing slowly all over the sky, but its done all the time with the old 172 and don’t say it isn’t so! Again, we’re duplicating real conditions here to show that it can be done.

You probably have about 85 knots (100 mph) indicated airspeed when you find yourself in a narrowing box canyon. Not enough power to climb – so we’re going to hammerhead…

1/ Full throttle, maintain level flight.

2/ Say to your front seat passenger “Do NOT touch the controls”

3/ Briskly pull back the yoke to go vertical, but not quickly enough to induce a high speed stall. Keep those wings level.

4/ As you go towards vertical, look out the left (pilot’s) side window. Keep pulling back to go vertical fairly quickly. You only have so much speed, momentum and power in this pig of a 172, so you have to achieve vertical as soon as possible.

5/ Don’t worry about the rudder too much. We’re going to hammerhead to the left to take advantage of the torque and p-factor on the 172. To be perfect you would need some right rudder on the way up – but save your concentration for nailing the vertical attitude out the left window… because that is the most important thing right now.

5/ When you are just about vertical, push forward to “neutral” elevator to keep going straight up. You must not go past vertical onto your back. Better to not quite reach the vertical than to go too far and over onto your back.

6/ You have maintained full power and will continue to maintain full power. This isn’t how we’d do a beautiful hammerhead in a flying contest, but the goal here is not art – it is to get you safely turned around.

7/ Your airspeed is dropping quickly – and here’s something to remember: your airspeed indicator is lagging your true airspeed so much that it is almost useless. If I told you to hammer the left rudder when you saw 50 knots (60 mph), you would be way too late, so…

8/ In a heavily loaded 172, hammer your left rudder the second that you achieve vertical. Trust me, you won’t have to bleed off any extra airspeed! Just do it.

9/ Remember, you still have full power on. As you hammer and hold full left rudder, the aircraft will pivot left around the yaw axis – but at this point you need to do two things to prevent the aircraft from falling onto it’s back…

10/ First, as the aircraft pivots in an arc to the left, the right wing is on the outside of the arc and is traveling faster than the left wing – which means it will be producing more lift than the left wing and will therefore try to roll you onto your back. SO… when you hammer that left rudder, feed in a right aileron to counter this tendency. The 172 has a 3 degree washout at the tips, so those ailerons keep working very well at low speed.

11/ Second, as you start to pivot, push forward just a bit on the elevator to make sure you don’t go over onto your back. If you keep full power on and give a little push as you hammer the left rudder, you may do a sloppy hammerhead, but you’ll never tailslide or go onto your back.

12/ As the aircraft is pivoting and the nose is dropping to the vertical downwards, be ready to neutralize the rudder or even go to right rudder to keep going straight down.

13/ Start your pullout smoothly but with authority. Watch out that you don’t pull too hard and get into a high speed stall! Keep those wings level to the horizon and recover level flight – now heading back from the whence you came.

14/ Adjust the throttle and pass out the sick-sacks to your amazed passengers.

That’s it friends. It sounds more complicated than it is, but any pilot reading the above will see exactly what we’re trying to accomplish.

Even a sloppy hammerhead will do the job, and shouldn’t put any unusual stresses on an aircraft – any more than an ordinary stall and recovery. I once saw a DC-3 hammerhead (honest!). It proved that the old saying is true: Any idiot can fly a DC-3, but it takes a real pilot to taxi one. We’ll have to leave the full story for another day…

Robert