Canard
Why is there a wing in the front and no horizontal stabilizer in the back?
The forward flying surface, called the canard, has a dual function. It produces approximately 60% of the lift in this aircraft but it also has control surfaces built into the rear portion designed to give the pilot the up and down pitch control usually provided by a horizontal stabilizer. Having both would be redundant.
Are Slicky's a biplane?
Yes and no. The Slicky design does use two large flying surfaces much like a biplane, but the wing in front is actually called a canard. The canard produces approximately 60% of the lift for Slicky's but it also helps control the pitch of the aircraft by incorporating elevators at the aft surface of the canard.Like a Quickie
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Merriam-Webster's Collegiate Dictionary has the following entry under 'Canard'.
Main Entry: ca•nard
Pronunciation: k&-'närd also -'när
Function: noun
Etymology: French, literally, duck; in sense 1, from Middle French vendre des canards à moitié to cheat, literally, to half-sell ducks
Date: circa 1859
1 : a false or unfounded report or story; especially : a fabricated report
2 : an airplane with horizontal stabilizing and control surfaces in front of supporting surfaces; also : a small airfoil in front of the wing of an aircraft that increases the aircraft's stability
So, it means 'Duck' in French. Apparently the shape of canard aircraft reminded them of ducks in flight. It is interesting to note that many who are not familiar with canard aircraft's performance and efficiency may think of the definition 1. when confronted by the numbers.
The definition 2, while mostly true, is not entirely accurate statement. In a conventional aircraft, pitch stability is a function of the lift generated by the main wing and the down force that is generated by the horizontal stabilizer. In this case, the main wing definitely can be called the supporting surface.
In case of a Canard aircraft, however, pitch stability is a function of the balance between the lift generated by the main wing and the canard. Since both airfoil is generating the lift, both can be called the supporting surfaces.
This leads to few other unique characteristics of the canard configuration, efficiency and stall resistance.
On the conventional aircraft, the lift generated by the main wing not only has to support the weight of the aircraft but also have to counteract the down force generated by the stabilizer. This means that portion of total induced drag (drag that is direct by-product of lift generation) is always wasted. On canard aircraft, all of the induced drag is associated with generation of lift enough to support the weight of the aircraft. For an aircraft of equal weight, canard aircraft incur less induced drag than conventional configuration.
On well designed canard aircraft, the canard is designed to stall before the main wing when excess angle of attack is encountered. This means that the aircraft will lose portion of lift that is forward of center of gravity and thus nose-down attitude follows. This increase the airspeed and prevent the aircraft from reaching main wing stall. When stick is held back, a canard aircraft will enter a gentle 'mushing' oscillation but will not break into stall.
Frequently, canard aircrafts are referred mistakenly as 'Stall Proof'. This is incorrect. It is possible, through improper loading or incorrect setting of canard incidence that main wing may stall ahead of the canard. As is the case with aircrafts in conventional configurations, stalling with CG too far aft can lead to a disaster. On a canard aircraft, main wing stall is also referred to as "deep stall". This is often unrecoverable. During the development of prototype Velocity, this condition was encountered. The test aircraft's main wing stalled and the aircraft became aerodynamically 'locked' where it started descending in flat attitude with almost no forward airspeed. The test pilot decided to ride the aircraft down to the surface and walked off uninjured. After minor repairs, the aircraft was returned to service. An interesting point to note is that the even though the aircraft was out of control, the bottom surface area of the Velocity prevented vertical speed to build.
Subsequent re-design of the airframe solved this problem on production Velocities and if properly built and configured, it should not enter deep stall inadvertently. Since stall is a function of angle of attack, it is very important to keep the relative incidence between the main wing and the canard during construction.