[Large AC] Evaluation of Flight Loads on Small Airlpanes with T, V, +, or Y Empennage Configurations

AC 23-9 · FAA

Public domain · FAAAdvisory Circulars

Overview

The [Large AC] Evaluation of Flight Loads on Small Airlpanes with T, V, +, or Y Empennage Configurations (AC 23-9) is a public-domain FAA advisory circular, republished here as a free chaptered HTML edition with a linked table of contents and the official PDF.

Publisher: FAA
Document: AC 23-9
Pages: 9
Chapters: 2

Key points

This advisory circular (AC 23-9) provides guidance for evaluating flight loads on small airplanes with T, V, +, or Y empennage configurations.
The document outlines acceptable means of compliance with Part 23 of the Federal Aviation Regulations (FAR) regarding design flight loads.
Design loads for unconventional empennage configurations should be validated through wind tunnel or flight tests until sufficient data is established.
The rolling moment induced at the intersection of horizontal and vertical stabilizers is critical for T-tail and + tail configurations.
For acrobatic category airplanes, higher combined loads on the empennage may occur during maneuvers, necessitating further investigation.

Frequently asked questions

What is the purpose of AC 23-9?

The purpose of AC 23-9 is to provide information and guidance for demonstrating compliance with the requirements of Part 23 of the FAR regarding the evaluation of design flight loads for small airplanes with specific empennage configurations.

Are the guidelines in AC 23-9 mandatory?

No, the material in AC 23-9 is neither mandatory nor regulatory in nature and does not constitute a regulation.

What should be considered when evaluating loads for T-tail configurations?

For T-tail configurations, the rolling moment induced at the intersection of the horizontal and vertical stabilizers must be considered, especially under conditions that generate lateral aerodynamic loads.

How should design loads be validated for unconventional empennage configurations?

Design loads for unconventional empennage configurations should be validated through wind tunnel or flight tests until an adequate data base has been established.

What is the difference in maneuvering load factors for different airplane categories?

The positive limit maneuver load factor required for normal category airplanes is 3.8g maximum, for utility category is 4.4g, and for acrobatic category is 6.0g.

Appendix 1

AC 23-9 1/27/88 Appendix 1 APPENDIX 1 1. NACA TR 1171 Effect of horizontal tail span and vertical location on the aerodynamic characteristics of NACA TN 2907 an unswept tail assembly in sideslip.

~~ R. Riley! 1954 2. NACA TN 3245 Calculated subsdnic span loads and resulting stability derivatives of unswept and 45° swept-back tail surfaces in sideslip and steady roll. M. J. Queijo; D. R. Riley, 1954 Effect of horizdntal tail chord on the calculated 3. NASA Memo, 4-1-591 subsonic span loads and stability derivatives of isolated unswept tail assemblies in sideslip and steady roll. K. W. Booth, 1959 4. AIAA Paper No. 74-1038 Determination of stability derivatives of isolated rigid tail assemblies in sideslip and steady roll. D. R. Riley, 1974 5. Engineering Sciences Contribution to rolling moment derivative due Data Unit to sideslip resulting from interference effects Memorandum No. 49 of fin or tailplane. R. W. Gilbey, Engineering Sciences Data Unit, 1984 6. NACA RM 154108 Investigation at high subsonic speeds of the pressure distributions on a 45 degree swept back vertical tail in sideslip with a 45 degree swept-back horizontal tail mounted at 50 percent and 100 percent vertical tail span. Harleth G.

Wiley; William C. Moseley, Jr., November 1954 An investigation at high subsonic speeds of the 7. NACA RM L55E04 effects of horizontal tail height on the aero dynamic and loading characteristics in sideslip on a 45 degree swept-back untapered tail assembly as determined from force tests and integrated vertical tail span loading. Harleth G. Wiley, William C. Moseley, Jr., June 1955 Low Speed aerodynamic characteristics of a 8. NASA TM X-3149 transport configuration having a 42 degree swept supercritical airfoil wing in 3 tail height positions. Paul G. Fournier; William C.

Sleeman, Jr., December 1978 9. NACA Rep. 1269 Theoretical span load distributions and rolling moments for sideslipping wings of arbitrary planform in incompressible flow.

M. J. Queijo, 1956

Next: Appendix 1 →

Appendix 1

AC 23-9 1/27/88 Appendix 1 10. NACA TM 856 The lift distributions of wings with end plates.

W. Mangler, 1937 11. NASA TR-R48 A systematic kernel function procedure for determining aerodynamic forces on oscillating or steady finite wings at subsonic speeds.

Charles E. Watkins; Donald S. Wooliston; and Herbert J. Cunningham, 1959 12. NACA RM 2992 Theoretical load distribution on fin-body RAE Report No. 2158 tailplane arrangements in a sidewind. J. Webber; A. J. Hawk, 1954