Hornet and Venom Redux wing metallurgy

The last two paragraphs are mine, not from Wiki!

Yes, Redux did continue. But it is just a polymeric adhesive that can be modified and improved, and it did evolve. The Wikipedia page (https://en.wikipedia.org/wiki/Redux_(adhesive))  is helpful and includes, for example:

Redux Liquid 775/Powder 775 was joined in 1954 by the subsequent Redux Film 775 system, used from 1962 by de Havilland (later Hawker Siddeley and subsequently British Aerospace) on the DH.125 and DH.146. Other users included Bristol (on the Britannia), SAAB (on the Lansen & Draken), Fokker (on the F.27), Sud Aviation (on the Alouette II/III), Breguet and Fairchild, the film-form having the advantage of greater gap-filling ability with no loss of strength over Redux Liquid 775/Powder 775, allowing for wider tolerances in component-fit, as well as easier handling and use and controlled ratios of the liquid/powder components. Other Redux adhesives available included “Redux 64”, a solution of the phenolic liquid and PVF powder, used worldwide for bonding linings to brake shoes, pads and clutches. The Redux range was subsequently expanded to include the current range of adhesives, both in single and two part paste systems and film forms, for both aerospace and industrial uses.

In modern terms, Airbus uses a skin made of GLARE. From what I remember this is on the fuselage upper skin of the A380. It is alternating layers of 2024 and glass-reinforced epoxy.

My favorite all-purpose resin is 3M EC2216. This epoxy has been used since the sixties where it was used to bond 2024 facings to aluminium honeycomb (eg, possibly on the Bronco flaps), and is still specified for various uses on Boeing airliners for glueing things to composites. It is good for wood, aluminium and modern epoxy-based composites.

Thanks Oracal and Nicko.  I am no Redux expert, but I always thought the technique carried through past the Hornet. I never really thought about the Al-Zn alloy issue, but if you were going to create the lightest and strongest Redux composite in the late 40’s, you would be attracted to the new ‘super Duralumin’ Al-Zn alloys, which came out as DTD specs about that time. Certainly, if the callout on the aluminium skin in a Redux composite is NOT DTD390, (SAE 2024) but a DTD6xx, then it might be Al-Zn, which later caused all the exfoliation issues in the 60’s as the zinc aggressively stole electrons from the aluminium. The modern restoration challenge is that the stronger Al-Zn alloy wing skin would be thinner than a 2024 replacement wing skin, to develop the same strength values.  I ponder that a modern composite of carbon fibre backed thin 2024 might be a pathway to rebuilding a Redux structure without re-introducing Al-Zn alloys or using thicker 2024 to build strength, with a cascading series of geometry problems. Still, that would be a big re-design…

Nicko. Your info is a useful addition to the debate.  It’s a shame you don’t have the vol 6. 

Ed, I think it may be more about the spec of aluminium used. The BAe Nimrod suffered badly with exfoliation corrosion in the wing stubs around the engine spectacles. Cause… cheap American spec’d material. The early remedy was to blend out the affected area while the aircraft was in the stressed-jacking position. ISTR we had 12 thou. to play with. When I was involved in the rectification work the aircraft had only been in service for about 5 years. 

The Vulcan and Canberra were both plagued by exfoliation corrosion problems too. 
 

Hi Ed.

I don’t believe there was adhesive bonding of any metal components, whether to other metal or wood, in the Venom. As far a materials and processes, I don’t believe there was anything different to the Vampire. Below is an extract from the Sea Venom FAW.53 General and Technical. It refers to riveted structure, and illustrations typically show representations of rivets or fastener holes. There may have been issues with the fuselage in the tropics although at least DH had moved on from casein. 

The Vampire had a range of fatigue lifes on items – from 600 hours to 1200 hours. I would be surprised if the Venoms were much different – especially as, if I recall correctly, the Kiwi Venoms in the Tropics were FB.4s, which had a lot of commonality with the Vampire. Even the FAW.53 had some major structural elements still with single-seat Vampire part numbers. Several of the life-limited items were steel, including those with 600 hrs. Some were aluminium alloy, including the lower spar cap. As much as the material itself, geometry is critical for fatigue. The main wing attachment fittings (steel) were redesigned with a more generous radius to improve fatigue life. The lower spar cap had a big problem where four skin panels met over the cap each with a fastener in it – four holes too close together. At least one of the fasteners was a PK screw –  with self cutting threads that are really good for starting cracks!

life-

Thank you Oracal. I don’t like to stray too far into the 50’s, too much louche morals with hip thrusting rock n’roll music and kerosine burning, swept wing, seagull splattering aircraft, so don’t have the referenced APs at hand. If anyone does, I would be very interested to confirm the Al-Zn alloy theory. 

Hi P&P. 
In the absence of DH material, AP 4335 Vol 6 (airframe repairs) for the Venom is very likely to provide an answer to the material used. Sorry, I don’t have a copy. 
 

Sea Venom is AP4360 Vol 6.