By Keith Kaniut
When I was younger and mostly immortal, I was once invited to fly an ultralight aircraft. The FAA defines an ultralight as a one-person aircraft that can weigh no more than 254 pounds empty, carry no more than 5 gallons of fuel and fly no faster than 63 mph. at full power in level flight. Many of the early ones were basically motorized hang-gliders and were controlled by the pilot shifting his weight.
At the time, I was a Navy flight instructor in Mississippi teaching new aviators to fly the T-2C Buckeye. I’d flown over a thousand hours in various Navy aircraft (mostly jets, admittedly) and considered myself a competent pilot. And I enjoyed trying new things. So, when the subject of ultralights came up during a flight debrief with a student one afternoon, I must have said something like “It must be fun – so basic and close to the pure experience of flying!” The student agreed and commented that 1) he owned one, and 2) it was parked at a nearby small airport, and 3) would I like to fly it?
His ultralight was a Lazair – a flying glider wing with two 5 hp. (!) motors on the wing, a very short fuselage boom and an unusual inverted “V” tail. This unique configuration meant that the engines were within reach if they needed to be restarted airborne (because you shut them off to practice gliding!), but the short V-tail meant that the rudders were not very effective. And with the long wing and most of the weight (the pilot) hanging underneath, it rolled very slowly into and out of turns.
I never even considered declining his offer and agreed to fly it the following Saturday morning. This was early in my Mississippi instructor tour. I was engaged but not yet married which was just as well. My future bride might not have approved (OK – absolutely would NOT have approved) of my adventure.
Saturday was warm and sunny with a slight wind when I arrived at the airfield. We pulled the ultralight out of the hangar and that’s when I noticed a possible problem. It only had one seat. If I had done my homework I would have known this.
I stated the obvious. “So this is to be a solo flight is it?” He assured me that with all my experience, the many hours flying Navy planes, that it would be a cinch. But yes, my first flight in this unfamiliar craft would be solo. Now the preflight brief became very important!
We discussed the controls, the motors, techniques for take-off and landing and critical airspeeds. He showed me how to start the engines while sitting in the “cockpit”. With the clarity of hindsight, I wished we’d talked more about the flight characteristics – how different it would be from everything I’d flown before. It was very basic; primitive in many ways. The airspeed was indicated by a clear plastic tube with a small disk inside – the higher the wind/airspeed, the higher the disk rose! The “Wind Monitor” was a reasonable substitute for an airspeed indicator as long as you knew the minimum and maximum allowable values. He said that the ultralight took off at 35-40 mph.
The wind had picked up a little and shifted to a slight crosswind. The grass strip runway was lined by tall pine trees the full length on both sides. They nicely blocked the wind but would be a terrible place to land.
I strapped in. We started the motors and I went through a fairly abbreviated preflight checklist: Flaps set (nope – don’t have them); Fuel mixture full rich: (no mixture. Just a throttle – never mind.); check the controls – move stick full right, left aileron goes down and right one goes up; Reverse stick and the ailerons also reverse; (that’s encouraging) Push the stick forward and watch the tail surfaces – they go down appropriately– all are free and operating in the expected direction. Engine temperature? Nope – don’t have that; Altimeter? Ah yes! Finally a familiar gauge! By now my student is looking at me expectantly and giving me the “thumbs-up” as in “Everything’s ready – go for it!” So I did.
With full throttle the little machine jumped into the air. Everything was going as expected until I hit a gust of wind coming over the trees on the upwind side of the runway. Suddenly, my right wing popped up. I looked down my left wing – straight at the ground. Under my right wing I saw nothing but sky! Not good. I applied full right-stick to correct. No effect. I remembered the rudder and threw in full right rudder to counteract the adverse yaw. Nothing seemed to be changing. It was time to make a choice. I realized that at the slow airspeeds of this ultralight, particularly with its long wing at low airspeed, the ailerons (for roll control) were not terribly effective. The best you could say about them is that they worked sluggishly and in their own sweet time! That wasn’t going to be good enough.
I had just enough altitude so I reversed the stick and rudder and rolled in the same direction that the aircraft seemed intent on going, lowering the nose slightly to maintain my airspeed. (If you can’t beat ‘em, join ‘em!) The result was a dramatic swooping 180-degree turn back down the runway opposite my takeoff. I wanted to get back over the cleared area away from the trees before resuming my climb. It worked. With my wings finally level I climbed to a comfortable altitude – 2,000 feet – while my heart slowly calmed. I circled the airport at this comfortable altitude and enjoyed the view. I had to admit it was pretty spectacular to be riding in the wind like this. I played with the controls until I was comfortable with their slow response and finally descended for an uneventful landing.
After taxiing back to where my student waited and shutting down the engines, I unstrapped and climbed out. He kidded me about my aggressive turn back down the runway. He thought I was hot-dogging it – showing off for the crowd. I corrected his misimpression, explaining that the wind over the trees and the relative lack of roll control were the actual culprits. We agreed that more discussion about the lack of aileron effectiveness at low speeds would have been helpful. We both had a chuckle at my expense. I politely declined his offer to fly it again with pending household chores my excuse.
As I drove home I realized that I didn’t need to fly another ultralight – at least until their design had improved to provide better roll control!
And that’s been my attitude, at least until two weeks ago when I attended the annual Experimental Aircraft Association’s annual Airshow and Fly-in Week in Oshkosh, Wisconsin. Things have improved significantly in the past 30+ years in the experimental and ultralight aircraft market. I might have to reconsider my position! (But don’t tell my wife…)
Technical Explanations
In a story like this I often have to use specialized terms or jargon that can be confusing if you’re not familiar with them. So, here’s a layman’s explanation for those who are interested.
Aileron: A hinged moving surface built into the trailing edge of wings, usually near the wing tips, used to change the lift on each wing in order to produce a roll. If the pilot moves the stick to the right, the aileron on the right wing goes up, reducing lift and causing the wing to go down while the left aileron deflects down, increasing lift, to roll the aircraft to the right. Notice that ailerons operate opposite to each other – if one goes up, the other goes down.
Adverse Yaw: When you attempt to roll an aircraft with the ailerons, the increased lift and drag on the wing where the aileron deflects downward, causes the aircraft nose to deflect (yaw) towards the downward aileron. So, if you roll to the right, the nose will tend to slide to the left.
Flaps: So, how is a flap different than an aileron? Flaps are similar hinged surfaces on the trailing edges of the wings. They are usually inboard of the ailerons and operate together and in one direction – down. When you “lower the flaps”, they deflect downward. This adds drag, allowing a steeper descent, and you increase the effective camber of the wing, allowing it to fly at a lower airspeed. This lower landing speed means a shorter landing rollout.
Camber: The camber is described by a line on the cross-section of an airfoil halfway between the upper and lower surface of the airfoil at each increment of distance from the leading edge to the trailing edge. It is more or less curved depending on the shape. The more curved this line, the greater the camber. A symmetrical airfoil has a camber line that is a straight line – defined as “zero” camber. Generally, the more the camber, the slower the wing is designed or able to fly.
Wind Meter: The wind meter is a cheap and lightweight substitute for a more sophisticated instrument to tell you how fast you’re flying. On the ground (at zero airspeed), if the airplane and its Wind Meter are facing the wind, it shows the wind speed across the ground. But once in the air, the airplane wing doesn’t feel the “wind”; just the air-flowing-over-the-wing, relative to the wing, not the ground. That’s why if you fly into a headwind, your ground speed will be less than your airspeed and visa-versa if you fly with the wind. In that case the wind speed is added to your airspeed, increasing your ground speed by that amount.
