Questions tagged [trim-tab]

Trim tabs are small surfaces connected to the trailing edge of a larger control surface on aircraft, used to control the trim of the controls, i.e. to counteract hydro- or aerodynamic forces and stabilise the boat or aircraft in a particular desired attitude without the need for the operator to constantly apply a control force. This is done by adjusting the angle of the tab relative to the larger surface.

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Could a trim system conceivably manipulate only primary surfaces?

Most airplanes' trim systems manipulate a tab associated with a primary surface. For example, a pitch trim tab (secondary surface) is attached to the elevators (primary surface) and will change the ...
Charles Nicholson's user avatar
5 votes
3 answers
416 views

Do aircraft fitted with both a trimmable horizontal stabilizer and a trim tab exist?

This question is restricted to trim on the pitch axis. Both trim tab and THS (trimmable horizontal stabiliser, a whole moving horizontal stabilizer whose movements are used as trim) are used to trim ...
Manu H's user avatar
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2 votes
1 answer
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How can I use the "control hinge-moment coefficient due to tab" for sizing a trim tab on an elevator?

I calculated the control hinge-moment coefficient due to tab by using the dimensions of a tail and its elevator. However, the trim tab dimension parameters in the calculations were approximated values ...
sibumiman's user avatar
7 votes
1 answer
485 views

Are elevator trim tabs required for an aircraft equipped with movable horizontal stabilizer?

The Bombardier C-Series aircraft has a movable horizontal stabilizer. It also has Trim Up/Down (discrete) switches in the cockpit. Is the aircraft also equipped with trim tabs? If so, when pilot ...
user2927392's user avatar
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What is an out-of-trim condition and how is it detected?

I am reviewing autopilot requirements which mention that whenever an aircraft's altitude changes as a result of air disturbance or an out of trim condition, the inertial sensors will detect this ...
user2927392's user avatar
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3 votes
2 answers
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How is an aircraft with a stabilator trimmed?

Many supersonic fighters have a stabilator to control pitch. My question arises when I cannot see any trim-tab on the stabilisator (e.g. on the F-16 or on the F-22). Other means to trim an aircraft ...
Manu H's user avatar
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8 votes
1 answer
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What is the working principle of trim tabs on the elevators?

Trim tabs are used on the tail's horizontal elevators to adjust its neutral position. What is the working principle behind this? How does this affect the sensitivity (the feel) of the pitch to the ...
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