Structural Repair

Structural Repairs

The maintenance manual has an extensive collection of structural repair details. Many cover "Grumman only" procedures like splicing the firewall and cabin floor with a factory repair section, or replacing the entire tailcone from the honeycomb aft.

There are also numerous factory repairs for mistakes made on the factory floor. These can be very helpful in the field to repair worn and damaged components.

The factory also published Service Kit 125A instructions which are the basis for repair of any debonded joint on the plane. The original need was because of the problems with debonding early on from the "purple glue", but there are other debonding and repair issues that can be addressed with the factory supplied data.

Because of the relatively unique construction of the Grummans, most shops are not familiar with repairs to honeycomb and bonded structures. A considerable amount of material has been added to AC 43.13-1B Change 1, that deals with bonded and honeycomb repairs.

Lower Cowling split

Requests for information on splitting the lower cowl on Tigers and Cheetahs was made on the GG and I'll post some pictures and an explanation of the means I used to repair lower cowls that had failed the spot welds and had cracking doublers.

Here is the Tiger lower cowl with failed spot welds and cracked doublers after removing the cowl from the plane and taking the doublers out.

This is a Cheetah LH lower cowl from the outside with larger ramp being drilled and clecoed in place. Paint is off because of the amount of metal work that was needed (with an English Wheel) to smooth the ripples that had been filled with bondo during previous work by persons unknown (no log entry!).

Here is the inside of that same Cheetah lower cowl half with the ramp in place and the new doubler mounted, ready to screw the other side on.

<To be continued>