Cliff Cordy

8. In general, Drag is proportional to Lift. Not true. In a fast plane (flying several times its takeoff speed) lift induced drag is trivial. Most of the drag is friction drag from airflow over the airframe. Much of the rest is engine cooling drag. 10. Canard aircraft: Lift = wing lift + canard lift. 11. Since canard lifts add, less area is needed. 12. Less area means less drag which = more efficiency. This is the same argument I've been using for 25 years. BUT, it ignores stability. I understand stability only in the most general terms. Stability involves center of lift, CG, and this feedforward effect between the wing and canard, which I don't understand at all. The Q2 canard carries 3/4 of the total weight of the plane, but it is only slightly bigger than the wing. Thus, the takeoff speed is high (75-80 mph) and most of that wing is not doing anything but causing drag and preventing stalls. Until I read Jones, I assumed this was true because they couldn't figure out how to get the CG further back with the front engine. Now I suspect it is necessary to make the plane stable, which my Q2 isn't quite (because I always fly it with CG near aft limit in order to get onto the runway with the tailwheel at least somewhere near the ground). There may not be a simple explanation to this, but if there is, I'd sure like to see it. Cliff

It is really hard to sort the effects of canard vs tail from good aerodynamics vs bad aerodynamics. Canard planes tend to have aerodynamic designs and their builders tend to be careful to do it right. If you look at the best of both cases, you find Klaus Sauvier flying 250 mph in his Vari-EZE powered with about 130 horses and Tracy Saylor flying his much bigger (more surface friction) aluminum (less smooth) RV-6 250 mph with a stock 180 horse engine. If you compare drag per unit surface area, it is pretty similar. Yesterday I noticed a reply to some other thread that Rutan himself finally agreed that the canard was not the most efficient. I've never seen that before. Rutan is an aerodynamics genius. If he changed his mind about canards after 30 years, there may not be a simple explanation of the effects that R. T, Jones was writing about. It also may mean that we are all chasing our tails. Cliff

I have been asked to write an introduction about my airplane experience. I learned to fly in the mid 70s, age approaching 40. This is too old, and I never became really comfortable flitting around in a little plane. Once I get above about 1000 feet AGL, I feel ok, but I like straight and level and smooth. I built a Q2 from about 1982 to 1989. It was a huge job. I figured I had 2500 hours in it at first flight. During this same period, I worked full time and did the course work for my PhD. Time management is essential. First flight lasted maybe 10 seconds before the engine died. It was another 500 man hours before I cured all the reasons for that. The engine was marginal. The carb was marginal. The fuel system was marginal. It was mathematically impossible for them to work together. At full throttle, it was far too lean. I had cracked cylinders and burned heads. This happened during high speed taxi tests and 7 short hops (about 5 seconds, that revealed no problems in the fuel system). Revmaster said the engine was 9.5:1 compression ratio and accused me of modifying their engine, which was patently false. They sold me new heads, 8.5:1 compression, which turned to plastic before I resolved the fuel problem (or may have been plastic before Revmaster sent them to me). I made a bunch of needles for the carb with more, much more, and hugely more, slope. The last one worked right. Then I bought two brand new VW heads and machined them myself. The engine hasn't missed a stroke since. The airframe design has problems. I'm a good engineer and cured all the obvious weak spots in the design as I built the plane. The wheel fairings were obviously bad, but at that time, I didn't know how to do them right, so I built them to spec. The engine cooling is terrible, very high drag. At that time, I didn't even understand cooling drag, so I built it to spec. I'm a good craftsman and made a smoother plane than I have seen elsewhere. I figure the engine is putting out 60 HP (2050 cc, 7.8:1 compression). I do 185 mph near sea level and 170 true at 8000 feet. Empty weight is 585 pounds, plus about 25 pounds of lead in the tail for balance. Flying alone, I (150 pounds) can typically climb about 930 ft/min near sea level. I've been to 10,000 feet, still climbing 300 ft/min. I'm convinced that if I did nothing other than make good wheel fairings and engine cooling, I could go over 200 mph. The aerodynamics of the air frame are obviously very good. The head tank had a microscopic leak somewhere. This caused a puddle of gasoline between the main tank and the canard. My transponder antenna sticks down into the canard. Gasoline got in and disolved all the polystyrene foam in the canard. I cut into the end of the canard and filled it with polyurethane foam, that won't dissolve in gasoline. Huge job. I also removed all the fittings from the gas tank and sloshed in a glob of epoxy all over the bottom part of the head tank. That cured the leak. About 5 years ago, I noticed the fuselage over the head tank had turned to rubber. It is hard to imagine fiberglass feeling like rubber, but it did. Gas fumes had seeped thru the fuselage skin and expanded the polyurethane foam in the glass-foam-glass sandwich. This broke all the epoxy pedestals that maintain the separation in the sandwich, which destroys most of the strength. It also turned both layers of glass to rubber, which eliminates any residual strength. Quickie didn't use the right kind of epoxy when they made the kit. I fixed that, but soon noticed the main tank was doing the same thing. I haven't fixed that. In the last 5 years, I've put all my effort into designing my new plane. I'll probably never fix the Q2. Fabrication will start in early 2007. Conceivably, first flight could be fall 2008, but I really expect spring 2009. That is about all of my story except to note that 1 month before the maiden flight of my Q2 (with me as pilot), I went for a ride with a friend in his Piper Pacer. He flew into the side of Mt. Hamilton, San Jose, CA, catastrophic crash, seemingly no chance for either of us to survive, and neither of us were seriously hurt. Seeing the prop stop 30 feet up on the maiden flight was seriously disturbing.

Does anyone know someone who is a competent fuel injection designer who might be willing to design a FI systyem for the Jabiru 3300?

R. T. Jones, at the end of his 1988 book "Modern Subsonic Aerodynamics", proved that under most conditions a conventional design is more efficient than a canard design, and a tandem wing design (as in a Quickie) is always much less efficient than either. To derive this result, he assumes a feedforward interaction between the aft wing and the forward wing that I don't understand. I have no formal training in aerodynamics, and not a whole lot of airplane experience. I can't make an intelligent comment about this. I certainly can't dispute a statement by R. T. Jones. Since this is a canard site, I'm hoping someone can shed some light on this subject at a level I can understand. Since this is a canard site, I'm hoping someone will say "Jones assumptions are not valid if you design the plane like this ----. I have degrees in math and physics, and a doctorate in electrical engineering. I'm not afraid of complexity. I just don't know much aerodynamic theory. Thanks, Cliff

When I started this airplane design, I was working with a friend. He has since been killed in a plane crash. He had found a brake that worked like a bicycle coaster brake. He said it is used in go carts. It is small and will fit entirely within an airplane wheel, so the wheel fairing can be narrower than with a disk brake. I saw some literature from the company, but Chuck kept it all. Chuck had corresponded with the manufacturer. After his death, I could find no record of this company in Chuck's papers. Can anyone tell me who this manufacturer is, and give me some contact info? Thanks, Cliff