Friday, April 16, 2021

All About Stalls (Flying)

 I just watched a YouTube video by Dan Gryder called Probable Cause. It is a series of investigations into various airplane crashes and the causes, with the purpose of learning and preventing similar accidents in the future.

The video I watched involved a student and an instructor who were practicing stalls and dove straight into the ground at high speed. His take was that the student was afraid of stalls and froze at the controls, and the instructor wasn’t ready to take it away fast enough.


It reminded me of myself when I first took flying lessons. I also had a fear of stalls. It was not helped when my first instructor demonstrated a spin to show me what was going to happen if I didn’t use the controls correctly to recover from the stall. 


For those who are not pilots, a stall does not involve the engine quitting on an airplane. It is when the wings go too slow to create enough lift to keep the plane in the air. In most airplanes the ailerons quit working as the plane stalls and falls, and the pilot must use the rudder to keep the wings level as he pushes on the yoke (or stick) to gain airspeed and then pull out of the dive. 


It is a skill that must be practiced until it becomes second nature, similar to recovering from a skid on ice in your car. It’s hard to practice enough when you are petrified by fright every time the plane stalls and falls off on a wing.


I had five instructors over a two year span while I learned to fly. Three of them were for a very short time, just filling in while the airport looked for a full time instructor. The two I learned the most from were Maxl Willis, and Bob Shermerhorn. 


The first time I went up with Bob he saw my fear of stalls and decided I needed to overcome that fear. So we climbed up to 10,000 ft so there was a lot of room between us and the ground.


He explained that he was going to take control of the yoke and throttle, and I was to put my hands in my lap. He said we were going to stall this plane for several thousand feet down to show that a stall is nothing to be afraid of. Meanwhile the rudder pedals were mine. When ever a wing dropped I was to step on the opposite rudder pedal. That turns the plane, speeding up the falling wing, and slowing down the rising wing. 


Bob kept the yoke back, with just enough throttle to hold the tail down, and we fell at least five thousand feet in the next minute or two. It wasn’t long until I got good at keeping the wings level with just the rudder. We did that falling leaf maneuver several times that afternoon, until I was getting almost comfortable with stalls.


 I got completely over my fear of stalls for sure the first time I went to the Reno Air Races. I watched Art Scholl do hammerhead stalls and tail slides, falling out of the sky, then recovering and going to the next maneuver. He also demonstrated flying by the stands while he stood outside the cockpit on the wing while waving at us. 


Leo Loudenslager demonstrated spins and snap rolls, which involves stalling just one wing and letting the plane twist through the air. I could see him using the rudder to switch from a left snap roll to a snap roll to the right and back again.


Bob Hoover demonstrated his “energy management” in his Shrike Commander by shutting off both engines and doing loops, rolls, and then landing and coasting up to the announcer’s stand without needing to restart or stand on the brakes.


After watching the pilots at the Reno Air Races, a simple stall seemed pretty tame.


Maxl Willis was a former helicopter pilot, and I learned about flight planning and we practiced cross country trips, including one to the little cafe at Denio Junction, Nevada, for one of those “hundred dollar” burgers. (That includes the cost of the flight). We learned about landing on dirt runways over power lines and doing it safely. 


The cafe had a sign that said, “Denio is so small the town hooker is a virgin!” I still miss Nevada humor!


After I got my Private Pilot’s License, I rented the local Cessna 172 for a while. Then several of us who were pilots at the power plant where we worked formed a partnership and bought a 1966 Cessna 172. 


It had several differences from the later model 172’s I had learned on. The most unusual was the Horton STOL modifications to the wings that involved a reshaped cuff on the outer half of each wing and a “fence” or fin on top of the wing that kept the airflow from angling across the wingspan. The main effect was to keep the ailerons working deep into the stall.


We couldn’t find any instructions or documentation on how the modification was supposed to be used. It made the plane almost useless for instruction. To learn stall recovery a different plane had to be rented. 


I decided to find out what I could do with the Plane and how to use that STOL (Short Take Off & Landing) modification. I climbed up to 10,000 feet and tried to stall it in every configuration I could think of. It would not drop a wing and full roll control stayed with the ailerons at all times. 


The surprise came when I held it in a full stall with just about half throttle. The airspeed dropped to zero with the nose pointed skyward, and yet the ailerons still worked. The plane was literally falling out of the sky tail first at 2000 feet a minute under full control.


I practiced stall recovery from that configuration and found that if I chopped throttle to idle and pushed the nose over, it stopped falling and was flying level at 40 mph in exactly 200 vertical feet. I did this many times, until I was sure it always worked and the maneuver came naturally to me.


The runways at Winnemucca had been extended at some time in the past to allow small jets to land there, so there was just 1000 feet to the first taxiway. I made a game out of landing on just the 1000 foot extension and turning off on the first taxiway. I usually had to add power and motor over to the taxiway. It was easy to land in less than 500 feet every time.


I never tried to land on any of the short mountain landing strips because the old tired Continental engine took a long time to get the plane up to speed for take off. With an engine upgrade to a new Lycoming engine it would have been a real STOL performer.


I did use the stall enhancement once at Farmington, New Mexico, when the tower asked me to “expedite my approach” as a twin Cessna was ten miles out on a straight in approach to Runway 7 also. I was “abeam the numbers” on downwind, so I told my wife Carolyn to “Hang on, this should be fun.” 


I pulled the nose high, added some power to hold the tail down, and turned toward the end of the runway. I turned a half circle directly to the runway, and as the plane lined up with the threshold, at 200 feet I pushed the nose hard over and cut the power. The plane immediately stopped falling and began flying. In just a couple of seconds we were flying level at 40 mph ready to land. I set it down easy and added power to taxi down to the midfield exit. When I announced I was clear of the runway, the tower thanked me for that expedited landing. I’m sure he was expecting a crash landing!


After several years the partners who owned the plane decided to sell to one of the owners and split the money. Some had quit flying, some wanted a more expensive plane to get their instrument rating, and I didn’t need the two extra seats in back, since my kids had grown up.


After some searching, I came across a Grumman AA1B two seat airplane with a canopy like a fighter plane and low wings. A pilot in Reno was stepping up to a bigger plane and was ready to sell his little plane. After agreeing on a price, and agreeing that he would pay for a new annual on sale, we made the deal.


He flew the plane up to Mountain Home, Idaho, for the annual inspection, so when the day came to close the deal, he flew to Winnemucca in his Piper Cherokee and picked Carolyn and I up and we went up to Idaho.


When the inspection was complete, I found a local pilot instructor who was familiar with the plane to give me a checkout ride. This little airplane was nearly the exact opposite of the Cessna. The wings were below us, not above. They were much shorter, only 25 ft tip to tip, and straight, with no stall enhancements added on. It was pretty obvious that when this wing stalled, it quit flying all at once. 


The cloud ceiling was only about 1200 feet that day, and the instructor refused to try a stall demo at that low altitude. He had heard about the reputation of Grumman Yankees, too. So we mostly practiced takeoffs and landings. When he was satisfied I could fly the plane he signed my log book and Carolyn and I were ready to fly our plane back to Winnemucca.


It was getting late in the evening, but the ceiling was lifting, and I could see clear sky toward the Rome VOR to the west, so I filed a flight plan and Carolyn and I boarded the plane and took off. The route is easy to follow, with roads beneath and VORs (VHF Omnidirectional Radiobeacons) all the way home. We turned at the Rome VOR in daylight and flew south toward Sodhouse VOR as darkness fell. 


Somewhere near the Nevada state border we both started to feel tired and sleepy. I was worried about an exhaust leak, so I told Carolyn to bundle up with her coat and I opened the canopy a small crack and opened the fresh air vents near our knees. It sure was cold, but it wasn’t far to Winnemucca. We landed without any trouble, and I tied the airplane down on the ramp and we got in the car and drove home. 


The next day I had a mechanic check the exhaust system for leaks, and there were none. It was just the end of a long, exciting day with our “new” airplane.


I went flying in the “Yankee” by myself in the next few days, and the first thing I wanted to do was check out the stall characteristics. It had a prominent placard on the dash right in front of the pilot that warned, “SPINS PROHIBITED”. I had also read that this plane had the worst record of spinning into the ground on turns to final of any airplane. That is always fatal.


Stalls no longer worried me at all, as long as I was high enough, so I climbed up to 10,000 ft. and tried a slow stall with engine at idle and full flaps deployed. It wasn’t nearly as scary as some had told me. There was no shaking as in a Cessna, but there was a stall warning buzzer that told you you were nearing a stall. The plane just suddenly dropped the nose and quit flying. Sure enough the ailerons became useless, but the rudder picked up a wing just fine, and if you kept coordinated there was no wing drop to worry about. 


A full throttle stall was much more exciting, as the torque of the engine ensured a wing drop at stall, but a stab at the rudder and a push on the yoke restored the plane to flying mode quickly.


I tried accelerated stalls in a 30º bank both left and right turns with full power, and it handled as expected with a break out of the turn, and a quick recovery with a push on the yoke.


I discovered that most stall recoveries took about 200 to 300 feet of altitude loss, so it was easy to see why a pilot wouldn’t want to stall when close to the ground on a landing approach. I changed my procedures when coming in for a landing with the “Yankee.”


The Pilot’s Operating Manual recommended 90 mph on downwind, 80 mph on base, and 70 mph on final in the landing pattern. The stall speed (with flaps) was 61 mph. It barely qualified to be certified in the “Normal” category. I knew a couple of pilots who swore they should’t have certified the plane at all, since it had been known to not recover from a spin. It only passed the certification by having that warning about SPINS PROHIBITED on the panel in front of the pilot.


I believe that every plane should be flown taking into account its strengths and weaknesses. A Grumman AA1B “Yankee” is not a slow, heavy hauler bush plane and shouldn’t be flown like one. It is light on the controls, and fun to fly, even if a little under powered and overweight. To compare it to cars, it is very like an MG sports car. Not really practical, but the most fun you can have flying for the least money possible.


I flew the whole pattern at 90 mph, and rounded the corners Navy style. Only when I was lined up on the runway with wings level did I chop the throttle, pull the nose up to lose speed and put in the flaps. It was easy to bring the plane down to seventy at the end of the runway and when I flared for landing, it soon set down on the pavement. I always held the nose high to keep the castering front wheel in the air as long as possible just to avoid extra wear and tear on the front tire.


I also had to change other things about cross country flying. I had to be more careful about the airports I chose to land on. I flew to Oklahoma a couple of times from Nevada and I had to move down to Double Eagle airport in Albuquerque from Santa Fe, because the altitude at Santa Fe was too high for the little “Yankee” and there were power lines at the end of the runway there. The “Yankee” only had 105 hp and short wings, so a longer runway was essential.


Once when flying to California, I needed to land for my passenger’s nature needs, so I landed at the next airport I came to. It was Cameron Park, a short strip in the middle of houses - an airpark. I started to fill the tanks, but when I looked back at the runway, I stopped at two gallons. In a couple of aspects I was lucky: it was not too hot yet, being morning, and the airport elevation was much lower than my home airport. 


I got out the POH and calculated the density altitude, and runway length, and decided now would be a good time to practice my short runway takeoff. I taxied the airplane as close to the fence as I could, stood on the brakes, and checked both mags, adjusted the fuel mixture for best RPM, then let the brakes loose and held the nose down until I got best angle of climb speed and pulled back and held the speed there until I cleared the house at the end of the runway by 50 or 60 feet. Then I lowered the nose to best climb speed and richened up the mixture a bit to cool the engine for the rest of the trip to Merced. I never made the mistake of landing at Cameron Park in my “Yankee” again.


When my son wanted to learn to fly, I had to search to find an instructor who would teach in my “Yankee”. I found one who was willing if I checked him out in the plane, and especially if I showed him the stall characteristics. He had heard all the horror stories of how “bad” it stalled.


I took him up to show him how it flew, and he liked the handling. A Cessna feels like a truck after flying in a “Yankee” for awhile. He wanted me to demonstrate stalls for him, so I showed him stalls with no power, stalls with full power, and ended with a full power stall in a turn at 30º banks angle. He agreed that it wasn’t that awful, just quick and sudden. 


He asked why I pulled the plane into the stalls, instead of “sneaking” up to them. I explained that I understood why he would ask that, because most people killed in stall/spin scenarios were not paying attention to the airspeed and were surprised when the stall happened, often on the turn to final approach. 


My philosophy is that you make the fatal mistake when you forget about the airspeed, and if you are close to the ground no amount of skill will save you from a crash. It serves no purpose to learn to recover from a surprise stall that sneaked up on you in a turn close to the ground. 


As one instructor told me, the three most important things to remember when close to the ground are 1. Airspeed, 2. Airspeed, and 3. Airspeed.


My son got about ten hours of flight instruction, but got a good scare when they forgot to switch to the fullest fuel tank in the landing pattern. The instructor knew instantly what happened when the engine quit, and switched to the other tank, but there are a few seconds until the fuel gets to the engine. 


In telling me about it later, the instructor praised my son for pushing on the yoke to maintain airspeed as they came in on final, rather than pull on the yoke to try to keep the plane in the air. They just missed landing in the sagebrush at the end of the runway, but they got to the runway alright. Both of them were obviously still shook up when they taxied into the airport, where I was waiting. 


My son lost enthusiasm for flying after that close call, and decided he would be happier on the ground, or letting me do the piloting. I did not try to dissuade him, because if it’s not fun to do, why do it? 


After 9/11, 2001, a lot of the fun went out of flying for me, with closer surveillance from the government, and nearing retirement with tighter finances coming my way, I decided to sell the “Yankee” to pilot friends at the Winnemucca airport. The engine was nearing overhaul time, and I needed the money for other things.


Now and then I think of getting back into flying. My wife died of Alzheimer’s a couple of years ago, and I am single now, with a little money left over, even after buying a house here in Oklahoma. But my eyesight isn’t so good anymore, and my heart is having electrical problems and will probably need a pacemaker soon. 


But I still look up at the students learning to fly overhead (I live under a practice area for Southeastern Oklahoma State University, a large flight school) and vicariously fly with them as they practice stalls. 


I miss the fun!