TimMcK_Aero... Very precise mass/balance requirements [static/dynamic] and very high structural safety factors equate to minimal anticipated forces and very high stiffness margins.
Here is how ARDCM 80-1 HANDBOOK OF INSTRUCTIONS FOR AIRCRAFT DESIGNERS [1958] summarized the design problem for control surfaces.
NOTE. HIAD skips around and is a-pain to follow. HIAD was replaced by AFSC Design Handbooks which took the HIAD apart and updated and reorganized the data/material/concepts/etc.
CONTROL OF VIBRATION, NOISE AND AEROELASTIC PHENOMENA HIAD Chapter 5
5.1 FLUTTER
... MIL-F-25352 lists detailed measures required by ARDC for avoiding flutter, ...
a. High torsional rigidity of fixed and movable control
b. Adequate mass balance or high rotational rigidities of movable control surfaces.
c. High rotational and torsional frequencies of control surface tabs or adequate mass balance of tabs.
d. Mass distribution such that the airfoil surface centers of gravity lie close to the airfoil
quarter-chord for the wing-aileron, stabilizer-elevator, and fin-rudder combinations.
e. Spans, masses, and moments of inertia of control surfaces and tabs kept as small as practicable.
f. Irreversible tab mechanisms located as close to the tab horn as possible and designed so that play can be kept to a minimum and within allowable limits.
g. Minimum coupling for tab flutter modes by locating the tab near nodes of important vibration modes of the supporting control surface.
HIAD Part B Airframe Design
5.2 TRIMMING CONTROLS
Design trim systems according to MIL-F-9490
5.2.2 TAB BALANCE
See MIL-F-25352 for mass balance of tabs.
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]
