Bullet Hole Repair

[AviaS199]

I'm sure some of you will think this is old hat, but the fact is, I've actually had a tough time tracking down definitive info regarding bullet hole repair during WWII. What method - or methods - were most often used, and what were the advantages/disadvantages of each method? I'm assuming they didn't have Bondo back then. Also, I've heard some vague references to tape. I've heard of heavy duty tape used on wing leading edges later on, but not back then. Thanks in advance, and sorry to make such a display of my ignorance.

[bdk]

All that should be in the structural repair technical order for US aircraft. Generally make the hole round and put a flush patch in with a doubler behind. Rivet everything together.

[shrike]

The FAA's AC43-13 has repair guidelines that are originally cribbed from wartime repair manuals.
The USAAF put out the MT 1-4xx series of tech manuals, one of which (and I don't have mine handy) is on sheetmetal including accepted repair practices.

For field expedient repairs of simple bullet holes (no structure involved, hole in the middle of the panel sorta thing) there is an AN patch, that is a slightly domed large area washer, backing nut plate and screw that can be inserted from one side and tightened like a molly bolt.
There is also the simple doped fabric patch.

Just FYI, Duck* Tape was invented in 1942-3 for sealing ammunition boxes, and may have been available.


*Duck, not Duct. So called because the backing is Cotton duck (from Dutch: doek, "linen canvas"), also simply duck, sometimes duck cloth or duck canvas, a heavy, plain woven cotton fabric. Duck canvas differs from plain canvas in that the threads in the former are more tightly woven. There is also linen duck, which is less often used.

[AvroAvian]

Well, I've learned something today. I was aware of 'duck' as a type of cloth, but never made the connection with cloth self adhesive tape.
Thanks shrike!

[ZRX61]

All that should be in the structural repair technical order for US aircraft. Generally make the hole round and put a flush patch in with a doubler behind. Rivet everything together.

Still one of the first things they teach in tin bashing class apparently. Flat & curved.

[hang the expense]

One of the P-40s I recovered out of Russia way back when had multiple bullet holes around the tail gear and up to the bottom of the stab.The shots were from the dead astern of the aircraft.The holes were filed smooth and were covered with dope and fabric.True story.

[ZRX61]

I was digging around a few days ago & found some patches I had to make in A&P school some time in the previous century...

[ZRX61]

Patch in previous post was a keeper, these two curved panels were (obviously) destined for the trashcan