cherry blossom
Senior Airman
- 511
- Apr 23, 2007
Does anyone know the story of the balance tabs on the Mitsubishi A6M Reisen?
The book by Yoshimura has on page 108:
...The findings had shown that flutter in the Zero occurred at almost the same speed whether the ailerons had balance tabs or not. The advantage of the balance was that it prevented the aileron from becoming too heavy at high speed. That made it easy to pull up from a deep dive using ailerons. Now, however, that was seen as a possible disadvantage. The easy use of the ailerons led to a tendency to maneuver the plane to the point at which wrinkling of the wings' surface plates became noticeable or even loose and their rigidity much lowered. For these reasons, pilots became suspicious of Zeros with balance tabs. Later the tabs were abolished.
An article by Joe Baugher has:
Beginning with the 128th Reisen, the aileron tab balance was linked to the landing gear retraction mechanism to improve high-speed control by reducing stick forces.
In order to correct an aileron flutter problem, a modified aileron tab balance was incorporated on the 192nd and subsequent A6M2.
One of my questions, on reflecting on the thread about designing a better aircraft, is whether the strengthened structure of the A6M5 (and later versions such as the A6M8) should have allowed the addition of tabs to increase the Zero's high speed roll rate. The A6M2 had a maximum diving speed of only 360 mph. Thicker skinning allowed the A6M5 to dive at up to 410 mph and further strengthening allowed the A6M5c to dive at 460 mph. Was the Zero's roll rate limited by the force that the pilot could supply or was the problem that the wing distorted to oppose the aileron deflection?
Yoshimura, Akira, translated by Retsu Kaiho and Michael Gregson. Zero Fighter. Westport, Connecticut: Praeger Publishers, 1996. ISBN 0-275-95355-6
Added as edit: The diving speed of the A6M2 should be higher and was probably 340 knots. See post below.
The book by Yoshimura has on page 108:
...The findings had shown that flutter in the Zero occurred at almost the same speed whether the ailerons had balance tabs or not. The advantage of the balance was that it prevented the aileron from becoming too heavy at high speed. That made it easy to pull up from a deep dive using ailerons. Now, however, that was seen as a possible disadvantage. The easy use of the ailerons led to a tendency to maneuver the plane to the point at which wrinkling of the wings' surface plates became noticeable or even loose and their rigidity much lowered. For these reasons, pilots became suspicious of Zeros with balance tabs. Later the tabs were abolished.
An article by Joe Baugher has:
Beginning with the 128th Reisen, the aileron tab balance was linked to the landing gear retraction mechanism to improve high-speed control by reducing stick forces.
In order to correct an aileron flutter problem, a modified aileron tab balance was incorporated on the 192nd and subsequent A6M2.
One of my questions, on reflecting on the thread about designing a better aircraft, is whether the strengthened structure of the A6M5 (and later versions such as the A6M8) should have allowed the addition of tabs to increase the Zero's high speed roll rate. The A6M2 had a maximum diving speed of only 360 mph. Thicker skinning allowed the A6M5 to dive at up to 410 mph and further strengthening allowed the A6M5c to dive at 460 mph. Was the Zero's roll rate limited by the force that the pilot could supply or was the problem that the wing distorted to oppose the aileron deflection?
Yoshimura, Akira, translated by Retsu Kaiho and Michael Gregson. Zero Fighter. Westport, Connecticut: Praeger Publishers, 1996. ISBN 0-275-95355-6
Added as edit: The diving speed of the A6M2 should be higher and was probably 340 knots. See post below.
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