Wing joiner location

[chris williams]

My Bergfalke 4 weighs 13lbs and flies with a single 15mm joiner, which is 485mm in length. Later versions were fitted with an extra 12mm joiner half the length of the original to avoid a slight tendency for joiner flex when filmed from an on-board camera... The same principle applies to all my other designs...

[Cliff Evans]

Be careful you do not make it too light! The performance will suffer

[AdamChambers]

Chris,

Is the joiner sat between the spars simply because its convenient and easier or is the location more complex than that?

Although I respect the idea of blade joiners, they are rare in many modern designs that use tubes or carbon square section.

[john greenfield]

Joiners, round, blade or any other shape need to be able to transfer the load effectivly to the wing structure. Trapping the main joiner between the spars is the easiest and lightest way to do this.
If the joiner is not between the top and bottom spars then heavy thick ribs will have to be used to transfer the load from the joiners to the spars and the load path is not straight so putting unnecessary stresses in the wings. A stronger (heavier) structure will be needed to counter these stresses.

AEB

[AdamChambers]

John,

Thanks. Im may end up adding weight Im trying to save.

Adam