In 1998 a retired Neurological-surgeon, Dr. Jack Barlass, approached us to build him a nostalgic War Bird. He had about 450 hours flying in the RCAF at the end of World War 11 and wanted to re-live some of those treasured flying memories.

Our first reaction was to build something really different and suggested building a airplane that looked like the Japanese Zero. He thought that would be all right, however the next day he decided on making it look more like a North American Harvard (T6 Texan). A few days later he had second thoughts about having a tail dragger because at 72 years of age he was not sure he wanted the added pressures associated with tail dragger flying. Our new suggestion was to come up with something that looked like an Aerocoupe. It would not have the War Bird look but would be a very safe and stable cantilever wing airplane. He accepted the idea, but we could tell he was not thrilled. The next day, full of enthusiasm he said , "lets build a King Cobra."

The design and building process began. Right off we all agreed that flight characteristics would take presidence over looks. We would try and make it look like the war bird while keeping in mind that it had to fly extremely well and be strong and safe. Because we have had so much success with the wing design and air foil of the Merlin and EZ Flyer it was decided that would be the air foil complete with yonkers ailerons, which work so well. The King Cobra look would come from the fin and rudder along with the canopy and to some extent the nose.

Initially the engine to be used was the Rotax 503, 52 HP but when the time for fitting up the engine arrived Dr. Jack decided to put a new Rotax 618 in his EZ Flyer and move the Rotax 582 from his EZ Flyer to the new airplane. Hence, althought the craft was designed to fly on 52 HP it was now going to get 65. As the designing and building progressed we became conscerned with the weight and balance. The C of G seemed to be moving further back, as design changes were being made. The day of final assembly came and a final Center of Gravity was determined. It was further back than we would have liked, but on a prototype airplane and wing the only way to really tell how everything is going to work together is to wind tunnel test it or fly it. We elected for the less expensive of the two options.

For the first test flight extreme caution was used. We had kept joking with Dr. Jack that it may not even want to fly. The monemt of truth came as I climbed in and started some taxi tests. The craft did more than we had expected with manouverability and visibility being exceptional. Next plan was to do some short hops down the runway to see "if" it was really going to fly. I remember my surprise as I opened the throttle a bit and with only 20 mph on the clock and some up elevator the nose wheel was comming off the ground. The large rudder gave very positive directional control with the nose wheel off the ground.

The next test was to get enough air speed to actually lift a few feet off the ground. I was expecting it to lift off at about 45 to 50 mph and was going to reduce the power and let it settle back to the ground. To my surprise, with the nose wheel off the ground and about 35 mph on the dial it became airborne. Another pleasant surprise was that it was not feeling tail heavy, but really wanted to fly. By now we were running out of day and the actual test flight would have to wait until the next morning, however there was still time for several more short hops down the runway, tesing the elevator, ailerons and rudder which harmouniously worked together.

The next morning after completing a few more test hops I took the airplane up for the first time. I was still concerned about the weight and balance with me in the airplane, as I was tipping in at about 250 pounds. I was pleasently surprised to find that the adjustable trim tab had enough allowance in it to allow me to fly hands off.

Immediately I was impressed with the cruise speed. Expectations were for a true air speed of 75 mph at moderate cruise rpm. To my pleasant surprise it was trueing out over 85 mph.

I had expected a good roll rate from the ailerons and the response was fantastic. Flying over the airport I did sone dutch rolls (aileron and rudder co-ordination maneouver) and found that the controlls were perfectly harmonized and comments from the ground later were that the craft showed the rolls with no adverse yaw appearing.

The new airplane behaved normally in slow flight, as well as high speed flight of over 105 mph (TAS 112 mph). The last of the initial tests was to see what its' stall and insipient spins would be like. Initially with some power on I started gently pulling back on the stick looking for the stall, but not sure what I would get. The airfoil used normally produced a very gentle forgiving stall, but this was the first time we had ever used it in a cantelever and a low wing aircraft. I was waiting for the stall at about 45 mph and it did not happen. Continuing to hold back on the stick the airspeed kept dropping, and I was starting to wonder if something was wrong with the pitot tube or the instrument itself, then at 30 mph the airplane burbled, broke and started flying again at about 35 mph. As I tried several more power on and power off stalls the results were the same. I had to kick rudder to make the wing drop for the insipient spin which it just flew right back out of. The King Cobra had exceeded what we hoped it would do. It flew faster and stalled slower than expected.

Having an idea for the airplanes envelope it was now time for the first landing.

I am a believer in keeping the approach "hot" and especially in an new airplane so the approach was at about 70 mph. Once down over the runway and with power backed all the way off the airplane seemed to want to float and float. The high lift airfoil and the low wing had built a nice air cushion under it and allowed me to slow right down before settling on to the ground. I had actually thought the runway was further beneath me than anticipated and was surprised when the craft kissed down like it was on glass. That seemed too easy so full power was applied and around I went again. Once over the runway the exact same thing happened. It was just too easy. I went around once more and the third time same thing.

I spent a few days "wringing out the airplane" before handing it over to its new owner, Dr. Jack. On his first flight he came in to land and overcontrolled on the elevator slightly which resulted in the airplane climbing back into the air without touching the runway. It was a combination of having too much speed and being too agressive on the elevator at flair. His next approach was a greaser as was every one since. You should have seen the smile on his face when he came back. After opening the canopy his first comment was "I finally have my fighter." Several months later Dr. Jack passed away with Cancer after putting over 50 hours on his new airplane. The near dozen people who have flown this airplane all remark on how manouverable, responsive and easy it is to take off, fly and land.

We have since bought the airplane from the Estate and have put it into full production. From date of order a kit can be available in ususlly 6 to 8 weeks.

The EZ King Cobra epitimizes a safe, enjoyable, relatively fast, good looking and affordable kit airplane. The fact that it is easy to build is just another bonus.

Blue Yonder Aviation

E-mail: ezflyer@ezflyer.com
Phone: 403-936-5767

Box 12, Site 9, RR #5
Calgary, Alberta t2P-2G6