QuickTalk 6 - PERFORMANCE PROVERBS
- Category: Q-Talk Articles
- Published: Sunday, 31 October 1982 06:11
- Written by Jim Masal
- Hits: 832
I'd bet that if you picked any popular homebuilt design at random and interviewed the designer, you would find that the most frequent need expressed by potential builders is more power. Such is the case with the Quickie - the originally tested 16 HP Onan soon grew to 18, then 22.5 and now a turbo-charger or Citroen conversion promises 25 HP or more. Why all the fuss and flurry over more power? Simple....PERFORMANCE!
According to a QAC brochure, the Quickie was conceived to be a cheap, reliable ship "light enough and clean enough to provide good performance and unequalled fuel economy".
First, what is a "good performance" to you, the builder? As efficient as we now know the Quickie to be, it will not deliver miracles on 18 HP. Conservative builders and flyers should expect a long ground run on takeoff, show climbout and above all should realize that this aircraft does not have the excess power to compensate for poor pilot technique. The Quickie does fly "good", but don't get overconfident or overenthused prior to first flight. Take the precaution of getting some very recent flying time in a taildragger or any light aircraft. Glider experience is good for the close ground landing attitude.
"Good performance" on low horsepower improves with lightness. Even a heavy DC-3 is a handful. Don't add epoxy, fiberglass, etc. beyond what the plans specify "just for good measure". As designed, the structure is plenty strong. This has been inadvertently proven in several accidents that did more damage to plane than pilot. Build it light and fly it light the first time. Consider only partial fuel and remove any items you can do without on the first flight.
"Good performance" on low horsepower also improves when the plane is aerodynamically clean. Do take great care in finishing all external surfaces, but especially the wing and canard. Study and follow the plans exactly. Sanding, filling and contouring is a thankless job. The temptation to take shortcuts is at its greatest. Don't give in; be patient and determined. At 50 feet off the deck heading for the barbed wire is no time to be wishing that your contouring was better. In fact, if you conjure up this image while sanding, you'll find the task a bit more pleasant.
As you build the airframe, keep streamlining in mind. Make all joints flow smoothly from one surface to the other. Round corners; look for flat areas disrupting the flow of the airstream. Look especially for a good seal and alignment of the canopy and cowling to the fuselage. Even earlier in the project, take time in cutting wing and canard foam as well as lining up the cores prior to glassing. Check, re-check and triple check. Be finicky and be thankful you're not working in aluminum.
Remember, the Quickie is performance sensitive to weight and drag. For every ounce of extra weight, for every square inch of drag area, you'll spend some horsepower and get less performance. If you build it heavy and sloppy, you will have more excitement on your first flight than you bargained for. And come clamoring back for more power.
If you build your Quickies light enough and clean enough, they will provide "good performance", just like QAC and Rutan expected them to. It's all in your hands - not theirs.
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