Spot weld construction

[Maxrobot1]

I understand that the F4U and B-26 Marauder construction involved a lot of spot-welding in place of rivets.
Was it any more difficult repair battle damage (replace aluminum sheeting, etc.) on spot-welded areas than rivets? At least with rivets, if you have to drill out the rivets you can see them. A painted spot-welded area would be another matter.
I've seen photos of B-17s and B-24s having whole sections replaced or recovered but not of B-26s or F4Us.
I know we have forum members who are involved in restoration efforts. Are spot welded areas more of a pain to work on than the riveted areas? Are flush rivets any worse? I know if you drill out a countersunk rivet just a tad too far, the replacement rivet head will not hold.
Do you know if the field mechanics had the capability to spot-weld in the field?

 

[FLYBOYJ]

I understand that the F4U and B-26 Marauder construction involved a lot of spot-welding in place of rivets.
Was it any more difficult repair battle damage (replace aluminum sheeting, etc.) on spot-welded areas than rivets? At least with rivets, if you have to drill out the rivets you can see them. A painted spot-welded area would be another matter.
I've seen photos of B-17s and B-24s having whole sections replaced or recovered but not of B-26s or F4Us.
I know we have forum members who are involved in restoration efforts. Are spot welded areas more of pain to work on than the riveted areas? Are flush rivets any worse? I know if you drill out a countersunk rivet just a tad too far, the replacement rivet head will not hold.
Do you know if the field mechanics had the capability to spot-weld in the field?

I don't think you'll find skins spot welded; I think you'll find the primary structure may be spot welded for the most part. I don't know about the B-26 but the F4U had a lot of its primary structure spot welded, as a matter of fact the Vought Kingfisher was the first production combat aircraft where its primary structure was spot welded.

As far as welding, most mechanics do get a course in welding but they might be limited to what types of repairs they can do in the field. Riveting is easy, weld repairs can be a chore and could cause more problems if done incorrectly.

 

[tyrodtom]

Spot welds, even if they're painted over, still are not hard to see.
Even if they're perfect you'll still be able to see a small ring.

 

[drgondog]

Welding was rare, always on steel structure of some type and occasionally on steel fittings. IIRC there was no aluminum welding on 6061 or 6064 in those days. As a structures guy I was always concerned about quality of the weld and ensuring that when tension was required that good 45 degree angle to get shear transfer..

skin panels should not be welded for weight, quality and repair reasons. additionally welding does not do well for reversible loads and resulting fatigue.

 

[Maxrobot1]

I was under the impression that spot-welding was used on the skin as a way of producing a smoother surface. As for interior structural components, that sounds reasonable.
Also I'm sure the engineers pointed out the weight of the rivets themselves would be deducted from the finished A/C even though it might only be a few pounds on a large plane.

 

[gumbyk]

I recall seeing an F4U at Ardmore that was being restored, and they had to mill all the spot welds off the fuselage skins to replace them without damaging the structure underneath.

 

[gumbyk]

Fuselage construction was a monocoque from the firewall aft, with a circular cross section back the the cockpit, where it transitioned to an oval section. At the time of its design gestation, a new technique had been developed for spot welding aluminium that promised lower drag compared with an equivalent riveted structure; Chance Vought took advantage of this new manufacturing technique.

History of F4U-4 Corsair Airframe - Graham White

The large fuselage panels were made of aluminum[20] and were attached to the frames with the newly-developed technique of spot welding, thus mostly eliminating the use of rivets.

Vought F4U Corsair - Wikipedia, the free encyclopedia

I think that most on them flying now have probably been riveted for ease of maintenance/repair.

 

[drgondog]

I was under the impression that spot-welding was used on the skin as a way of producing a smoother surface. As for interior structural components, that sounds reasonable.
Also I'm sure the engineers pointed out the weight of the rivets themselves would be deducted from the finished A/C even though it might only be a few pounds on a large plane.

Rivets are heavy