In March of 2001 we were contacted by the Pepsi Aerobatic people because they saw a bulliten we put out about cracks that form in the fuse bulkheads at the main spar attach areas of the Super Chipmunk. We have developed a fix for this problem that is inclusive of a new lower spar carry through / cap. Bulkheads are reinforced with 4130 shear plates and new 2024-T3 formed bulkhead verticals are installed. Wing attach fittings are reamed to fit standard NAS high strength bolts instead of the impossible to find Chippy bolts.
Cracks in the bulkheads caused by the lower carry through flexing
Some of the peices for the bulkhead reinforcement
New improved solid 4130 cond N carry
Belly skin removed to facilitate repair mod.
New parts installed as well as new carry through / Cap (bulletproof)
The whole affair is tied together with the upper spar carry through creating a very strong box arrangement