Freeze Plug retaining strap.
Freeze Plug retaining strap.
(OP)
I am repairing a damaged hole in the T chord flange of trailing edge structure of the wing by freeze plugging. There is a fitting installed at the location and the hole (0.25 inch Diameter) goes through the T chord flange and fitting.
The damaged hole is in the flange of the T chord and the fitting hole is undamaged.
The hole is used to secure an aerodynamic panel using a screw.
To retain the freeze plug, I will be installing a strap.
I would like to know how to work out the thickness, material and length of the strap. The chord and the fitting are made of 7075-T6.
The damaged hole is in the flange of the T chord and the fitting hole is undamaged.
The hole is used to secure an aerodynamic panel using a screw.
To retain the freeze plug, I will be installing a strap.
I would like to know how to work out the thickness, material and length of the strap. The chord and the fitting are made of 7075-T6.





RE: Freeze Plug retaining strap.
All you are trying to do is trap the "free" side of the plug. This would be easy if the hole was for a permanent fastener - just use a washer larger than the freeze plug.
Pretend you are reinforcing a blendout on the T and apply the straps (you will want one on each side of the T) per SRM guidelines for extrusion repair.
RE: Freeze Plug retaining strap.
If the stack up is fitting, T-Chord, panel, then if the freeze plug is confined to the T-Chord, no retention is required as it is trapped between the fitting and the panel.
Another option is to use a countersunk freezeplug with the csk side between the fitting and the T-Chord. This would be fully self-retaining.
You need to look at the straps anyways from a strength restoration issue as mentioned from bf109g.
jetmaker
RE: Freeze Plug retaining strap.
RE: Freeze Plug retaining strap.
cheers