De Havilland Mosquito (Wood vs. Metal)

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ETOPs-120 was approved in 1984 and that also hammered the L-1011. A 767-200 would burn about 3.5 tons less fuel on the same route. Spend a couple million upgrading a -200 to the ETOPs-120 requirements and it paid for itself rather quickly on fuel savings alone. Add in decreased maintenance costs, and it was even faster.
 
Would airlines have placed those orders when we have what is presumably a more economical-to-operate plane coming online?
According to the marketeers at Lockheed, yes.
The airline would probably see twins as more profitable given that seating isn't that different but maintenance is presumably reduced by one-third?
With one less engine, of course, but I think seating configurations enabled more passengers compared to early 767s IIRC.
 
According to the marketeers at Lockheed, yes.

With one less engine, of course, but I think seating configurations enabled more passengers compared to early 767s IIRC.

Right, 767s didn't have the capacity, but at the same time profit margin (from an airline perspective) is about fuel and maintenance expenses divided by passenger capacity to deliver more profit per seat.

Forgive my business-manager approach to this -- and no doubt Lockheed execs had much better insight into this that I could hope to have.
 
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And one less in the cockpit with the financial and safety benefits that brings - not that the bean counters ever look at safety benefits.
 
Is it sacrilege to post this?

Warbird From Scratch: A Homebuilt Spitfire

It has an Allison V-1710.

I used to work at the shop that built Bob Deford's Allison. That's a very nice airplane, very well built / detailed, and well-flown. The control stick is genuine Spitfire and it has about 95% of the performance of a genuine Spitfire. It still lacks a high-altitude boost system but, with today's IFR requirements, nobody flies warbirds way up there anyway. They like to be able to loop and roll and chase each other. So, there is no downside to the Allison's altitude performance today.

Those who think they could tell it apart from a real one need to know it is exactly the same size as an original. The real "giveaway" from 20 feet away is the lack of rivets in the wings. Mr. Deford usually doesn't push it too hard, but will mix it up with other warbirds at suitable power settings when they encounter each other. He's had one issue with the Allison, and was at speed over his home airfield when it happened, so it turned into a non-event. It was a broken part that didn't self-destruct the rest of the engine. Easy fix once the engine was pulled. Our shop had never seen that particular part fail before and hasn't seen it since, either.
 
Does this home built Spit (gorgeous) have a serial number/builders plate?
 
One thing that I do wonder about as far as the Mosquito, Hornet, and the front fuselages of the Vampire and Venom is how easy they were to repair from repairable/salvageable damage vs metal monocoque airframes? I'm well aware that those aircraft were durable if properly maintained, but what about repairs from flak/bullet/cannon shell holes or from forced landings? We do have to remember that the Mosquito/Hornet fuselages were built similar in construction to modern F1 cars, Indy Cars and Le Mans Prototype cars. Just replace carbon fiber reinforced polymer/aluminum honeycomb/carbon fiber reinforced polymer with aviation plywood/balsa wood/aviation plywood.
 
This has been discussed through out other threads. As an A&P who worked on wood and metal aircraft, putting it in a nutshell, IMO wood sucks. Harder to repair, more susceptible to damage from elements, controlled environment needed for larger repairs, I can go on....,

Working with wood is not the same as modern composites
 
I read about the repair of a Mosquito on the airfield. The air crews were a bit concerned to see the people from de Havilland tearing the wings to bits with saws chisels and planes.
 
As with all aircraft types, the Mosquito had a range of approved repairs, to include cutting off entire sections of wing and splicing in new sections. There's a WW2 vintage film of the Mossie showing this work in progress. This is exactly the sort of battle damage that the repair was designed to address:



There were similar mechanisms for repairing small holes in the fuselage.

For people used to working in metal, the Mossie was definitely harder to work and repair. However, in WW2 there were scores of skilled woodworkers for whom this sort of task was pretty much routine once De Havilland developed the approved repair processes.

And, yes, they did literally saw through the spars and wing surfaces and simply added a spare Mossie wing section that was fashioned to fit. Try doing that on a metal airframe.
 
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I'd be more concerned about fuselage damage than wing damage to the Mosquito or Hornet than to the wings. Remember, the fuselages are built like modern racing cars as far as using a sandwich composite structure with molds and adhesives (though carbon fiber and aluminum honeycomb is chalk and cheese to plywood and balsa). I can see anything beyond minor damage from a wheels up landing or gunfire causing a Mosquito or Hornet to be or almost be a write off. In fact, the plane pictured above was declared a write off once the damage became fully apparent (we're looking at the good side in the image).

Of course, these are combat aircraft and thus may or may not return from a mission, and the Mosquito was sold as being made largely out of non-strategic materials. Which in a total war like World War II is desirable, especially if the trade off is seen as worth it. But it also shows the dedication of the owners of warbirds and those who maintain and restore them. It also above all else helps, of course, that these planes are now operating in peace time conditions, where they have (relatively) little chance of being damaged or destroyed, and can get the preservation that they (at least in our opinions) deserve, be it wood or metal.

It does make for an interesting "what if" as far as if the Mosquito or Hornet were all metal instead of mostly wood. Namely (other than repair, maintenance, and long term preservation) would they have gained anything performance-wise from being made out of aluminum? The Lavochkin La-9 was a redesign of the earlier La-5 and La-7 to be made out of aluminum vs wood. Using the same engine, it gained (partly due to lighter structure, partly due to laminar flow wing) nearly 20mph in top speed, was more durable (the Lavochkin wood fighters had some durability issues like most wooden aircraft did), and, above all else, had over twice the range on internal fuel vs the La-5 and La-7 and carried more armament for about the same weight.

And it's not like DH were total newcomers to metal aircraft. They knew that all-metal airframes were the future/way forward, and Ronald Bishop, who designed the Mosquito and Hornet, designed the Flamingo, Comet and Sea Vixen, all all-metal aircraft. And if he and DH had their way, the Vampire and Venom would've been all metal as well instead of using the ply/balsa sandwich for the front fuselage. The original DH 99 version of what would become the Vampire was intended to be all-metal.
 
I would love to see that if you happen to have a link.

Minor repairs on the Mosquito were definitely more labour intensive than for an aluminum aircraft. Most would have involved cutting out the damage to sound material, creating scarfs on the remaining skins (usually 1;12 slope) shaping and gluing a patch to fit the hole, gluing a wood reinforcing patch over that and then adding a fabric patch over the reinforcement on the exterior side. And, almost always, there would have been two skins to deal with (inner and outer).

Here's a prepared repair patch on our Mosquito where only the outer skin needed fixing. The plywood patch is about 2mm thick and you can see the very shallow scarfs on the patch and on the prepared existing skin. You can also see a finished repair shown as the lighter material at top left. In these cases, there is no reinforcing patch glued over these repairs as our example will not be a flyer and we want to preserve the smooth lines.

 
Picked up the Dec 2022 edition of Aeroplane this am which has an article titled "Mosquito plywood problem solved" highlighting some of the difficulties encountered restoring Mosquito B.35 RS700 in Canada. (Crimea_River - Is this the Mossie that you are working on?). This bit is worth quoting:-

"All British and Canadian built Mosquitos used Baltic birch plywood made to 6V3 [a British Standard]. Part of what that means is that every sheet, regardless of its finished thickness, is comprised of just three layers or veneers. The plywood on the Mosquito varies in thickness from 1.5mm to 6mm. That means the veneers are custom-cut for thickness on each sheet. Where it gets even more complicated is that the grain direction is also specified by de Havilland for every sheet used on the aeroplane. In some places it's 'normal' meaning the grain of the two outer layers runs the length of the sheet; some runs crosswise on the sheet and some runs at a 45 degree angle. The grain direction was decided based on the structural stresses on each section of the airframe."
 

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