DaveD
Well-Known Member
So down at the lighter end of things there seems to be two competing methods of designing trim systems. Either an aerodynamic trim tab mounted on the control surface or a spring loaded arrangement that applies a force to bias the neutral position of the controls. (I know that some commercial jetliners use a jack screw to change the incidence angle of the whole horizontal stabiliser for trim, but I don't know if any light aircraft have this arrangement).
I'm interested in the comparative advantages and disadvantages of the two types. My gut feel is that the spring type is less common, but that's only a guess!
Off the top of my head, a trim tab is not limited to smaller aircraft as it can produce large forces even when manually controlled by the pilot (WW2 bombers for example). A spring/bungee type trim would undoubtedly get heavy if large forces are required. Are there any other considerations? I think I read about sloppy trim tabs being a flutter risk?
Any strong opinions out there? Or is it a case of "They both work so just choose one!"
Cheers
DD
I'm interested in the comparative advantages and disadvantages of the two types. My gut feel is that the spring type is less common, but that's only a guess!
Off the top of my head, a trim tab is not limited to smaller aircraft as it can produce large forces even when manually controlled by the pilot (WW2 bombers for example). A spring/bungee type trim would undoubtedly get heavy if large forces are required. Are there any other considerations? I think I read about sloppy trim tabs being a flutter risk?
Any strong opinions out there? Or is it a case of "They both work so just choose one!"
Cheers
DD