Project: Q+2     -     Entry

Feb 20, 2022 0.4 Sparrow Strainers Category: Research
The Q2 and Q200 are both known to "tuck" at speeds above and below approximately 150 mph. This condition is tied to the trim speeds and attitudes of the aircraft when the elevators "float" trailing edge up, causing the nose to pitch down. While fixed aerodynamic tabs on the elevator (colloquially known as "sparrow strainers") were called out in the QAC plans for the LS1 canard, no such change was ever factory recommended for the earlier GU canard. Both David Smith ( https://www.youtube.com/watch?v=MHrDOafL2j0&t=925s ) and Peter Mazsaros claim the addition of sparrow strainer(s) is also beneficial on the earlier canard ( https://youtu.be/LCPd4h4ElV0?t=792 - Note that after 15m38s Peter says "sparrow strainers" when he means "vortex generators"). Further research is needed to see if the aileron reflexor addresses this issue or not.

NOTE: Elevator float is a known issue with the early laminar flow airfoils due to the aft pressure loading such airfoils rely on to obtain their laminar flow. This behavior is no issue on a fixed wing. However, when such an airfoil is used on part of the wing with an elevator or aileron this aft portion of the airfloil is no longer fixed and the air can "push" the trailing edge up. Modern laminar flow airfoils are designed to account for this phenomenon.

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