An airfoil (200; 300; 500; 700) of a gas turbine engine comprising: a shell (202; 302; 502; 602; 702) having a first receiving channel (322; 522; 622; 722) and a first engagement element (324; 524; 724) arranged along the first receiving channel, the first receiving channel extending in a radial direction along the shell between a first end and a second end of the shell in the radial direction; a spar (204; 304; 504; 604; 704) having a second receiving channel (330; 630; 730) and a second engagement element (332; 532; 632; 732) arranged along the second receiving channel, the second receiving channel extending in a radial direction along the spar between a first end and a second end of the spar in the radial direction, wherein the spar defines an inner cavity (318; 518); and a connector (206; 306; 406; 506; 706) configured to be installed between the shell and the spar to connect the shell to the spar to allow for thermal growth of the shell relative to the spar, wherein the connector comprises a first engageable portion (340; 440; 740) and a second engageable portion (342; 442; 742) connected by a link, wherein the first engageable portion is configured to engage with the first engagement element of the shell and the second engageable portion is configured to engage with the second engagement element of the spar, wherein, when assembled, an outer cavity (320; 520) is formed between the spar and the shell, characterized in that the first engagement element, second engagement element, the first engageable portion, and the second engageable portion are configured to define an axial flow path (214; 314; 514; 714) through the outer cavity. a shell (202; 302; 502; 602; 702) having a first receiving channel (322; 522; 622; 722) and a first engagement element (324; 524; 724) arranged along the first receiving channel, the first receiving channel extending in a radial direction along the shell between a first end and a second end of the shell in the radial direction; a spar (204; 304; 504; 604; 704) having a second receiving channel (330; 630; 730) and a second engagement element (332; 532; 632; 732) arranged along the second receiving channel, the second receiving channel extending in a radial direction along the spar between a first end and a second end of the spar in the radial direction, wherein the spar defines an inner cavity (318; 518); and a connector (206; 306; 406; 506; 706) configured to be installed between the shell and the spar to connect the shell to the spar to allow for thermal growth of the shell relative to the spar, wherein the connector comprises a first engageable portion (340; 440; 740) and a second engageable portion (342; 442; 742) connected by a link, wherein the first engageable portion is configured to engage with the first engagement element of the shell and the second engageable portion is configured to engage with the second engagement element of the spar, wherein, when assembled, an outer cavity (320; 520) is formed between the spar and the shell, characterized in that the first engagement element, second engagement element, the first engageable portion, and the second engageable portion are configured to define an axial flow path (214; 314; 514; 714) through the outer cavity.