swampyankee
Chief Master Sergeant
- 3,986
- Jun 25, 2013
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In general, before aircraft enter service predicting whether they'll be successful or not is never easy. In the case of the Mosquito, one must remember that the Mosquito was not built in response to an official RFP from the Air Ministry; it was built as a speculative venture by DeHavilland (De Havilland Mosquito | BAE Systems | International) after the company was ordered to shut up and build wings as a sub-contractor.
DeHavilland was probably uniquely capable of building a high-performance wooden aircraft, primarily as it had experience with the DH.88 Comet and (less successfully, given that one of the seven built crashed, with no deaths, due to "the wing starting to break up" [De Havilland DH.91 Albatross Transport], causing the DH91 to be withdrawn from service). I think secondary reasons may have been that the Air Ministry was open to such private ventures because of their desperation.
The A-26 Invader originally began as a private venture on the part of the Douglas plant at El Segundo, California. In the autumn of 1940, Douglas began a preliminary design study to develop a common successor to the Douglas A-20, Martin B-26, and North American B-25 bombers, none of which had yet entered service with the US Army Air Corps. The Bomber Branch of the Experimental Engineering Section at Wright Field, Ohio assisted in this effort by pointing out some of the deficiencies of the company's DB-7 twin-engined attack bomber that they had evaluated--lack of crew interchangeability, insufficient defensive armament, inadequate offensive firepower, and excessively long landing and takeoff distances.
At the end of January 1941, a team led by Edward Heinemann and Robert Donovan had come up with a proposal for a new twin-engined attack aircraft that would satisfy these requirements. It had a broad general family resemblance to the A-20 Havoc which was just then entering service with the Army Air Forces. It featured a mid-mounted wing with a laminar flow aerofoil and which was fitted with electrically operated double-slotted flaps. The aircraft was to be powered by a pair of 2000-hp Pratt & Whitney R-2800-77 air-cooled radials. The aircraft was to have a large internal bomb bay capable of carrying 4000 pounds of bombs or two torpedoes, and was to be fitted with external racks underneath the outer wings for additional ordnance. The defensive armament was to be provided by a pair of remotely-controlled dorsal and ventral turrets, each housing two 0.50-inch machine guns and operated by a gunner sitting in a separate compartment behind the bomb bay.
A decision was made that the aircraft would be built in two separate versions, a three-seat light bomber version with a transparent nose for a navigator/bombardier and a two-seat night-fighter version with a solid nose carrying heavy forward-firing armament and AI radar. The two versions were to be essentially identical except for their noses.
The mockup was inspected between April 11 and 22 of 1941, and on June 2 the War Department authorized the construction of two prototypes under the new designation A-26. The first aircraft was to be a three-seat attack bomber version with a transparent nose and was to be designated XA-26-DE. The second aircraft was to be a two-seat night fighter version designated XA-26A-DE. Three weeks later, the contract was amended to include a third prototype designated XA-26B-DE. It was to be a three seat ground attack aircraft with an unglazed nose housing a 75-mm cannon.
it had some "industrial" bottlenecks not easy to overcome to increase the production to huge numbers in short times.
So, where were these bottlenecks on what form did they take? Books I have on the type mention no 'industrial bottlenecks' concerning its production, so where did you find this claim?
According to Sharp and Bowyer in their book Mosquito (Crecy, 1995), de Havilland made outlandish promises in July 1940 while the prototype was under construction, of 50 Mosquitoes by December 1941, but the Air Ministry told Hatfield not to escalate tooling too much as the firm might not be able to deliver on its promise. The area that really facilitated production of the type was the fact that major components were sub-contracted and this saved expectations at Hatfield in terms of tooling and staffing for the future. The book also mentions the fact that sub-contracting actually sped production to meet demand and all evidence in the book shows that things happened smoothly as a result of the decision to sub-contract, with companies willing to facilitate this, which meant that the flow of airframes began to meet demand as it was at the time. One area identified as problematic was the Air Ministry's demands for both fighter and bomber types, not being entirely clear of the numbers it wanted of each to begin with.
The following from the book indicates the RAF's receipt of the type :
"After taking their fiftieth aircraft in mid-March 1942, the RAF had fifty more in the next two months, the 101st by 30 May. They had the 408th by 28th November (Hatfield 366, Leavesden 42), and the 1,000th in June 1943 (Hatfield 775, Leavesden 198 by 21 June). Thus the production rate was one a week in late 1941, three a week in early 1942, eight a week by midsummer, 12 to 14 a week by the end of 1942 and double that a year later from all sources."
I'm also well aware that the Lancaster is a larger and more complex aircraft to build than the Mosquito, but the point is that within a similar time period, the Mosquito's production figures are comparable to other types built by Britain during the war.
So, where were these bottlenecks on what form did they take? Books I have on the type mention no 'industrial bottlenecks' concerning its production, so where did you find this claim?
According to Sharp and Bowyer in their book Mosquito (Crecy, 1995), de Havilland made outlandish promises in July 1940 while the prototype was under construction, of 50 Mosquitoes by December 1941, but the Air Ministry told Hatfield not to escalate tooling too much as the firm might not be able to deliver on its promise. The area that really facilitated production of the type was the fact that major components were sub-contracted and this saved expectations at Hatfield in terms of tooling and staffing for the future. The book also mentions the fact that sub-contracting actually sped production to meet demand and all evidence in the book shows that things happened smoothly as a result of the decision to sub-contract, with companies willing to facilitate this, which meant that the flow of airframes began to meet demand as it was at the time. One area identified as problematic was the Air Ministry's demands for both fighter and bomber types, not being entirely clear of the numbers it wanted of each to begin with.
The following from the book indicates the RAF's receipt of the type :
"After taking their fiftieth aircraft in mid-March 1942, the RAF had fifty more in the next two months, the 101st by 30 May. They had the 408th by 28th November (Hatfield 366, Leavesden 42), and the 1,000th in June 1943 (Hatfield 775, Leavesden 198 by 21 June). Thus the production rate was one a week in late 1941, three a week in early 1942, eight a week by midsummer, 12 to 14 a week by the end of 1942 and double that a year later from all sources."
I'm also well aware that the Lancaster is a larger and more complex aircraft to build than the Mosquito, but the point is that within a similar time period, the Mosquito's production figures are comparable to other types built by Britain during the war.
NIce question.
I guess from my perspective the question isn't could you build as mosquito from aluminum, which it seems that you could, but could it be built better in North America. Plywood and laminated wood assemblies were quite advanced in the US and Canada and a number of technologies associated with them were being pushed by the war effort. Preforming plywood assemblies and structural laminating in particular advanced rapidly and I suspect that a Mosquito manufactured in the US would benefit from the incorporation of some of these technologies. Mixed material assemblies (wood aluminum) were not as far along in the US, but one could imagine that this technology would develop faster if there was a need such as a significant emphasis on uses in aviation.
I'm aware that the Curtis C-76 Caravan debacle counters this argument, however, there were a number of poor choices associated with that project, such as mahogany core vs balsa core plywood and use of a bad manufacturer.
Sticking with wood has a number of advantages. You aren't competing for materials and manpower with other major aviation projects. The aircraft would be sooner to production as you climate the time required to reverse engineer and test a new airframe. There is significantly more latent capacity in the laminated wood industry than aluminum which can be ramped up more quickly. More Mosquitos sooner.
Just my thoughts.
Kk
Just for general interest:
The Plane That Saved Britain: The Plane That Saved Britain - On Demand
At about the 10minuite mark, one of the orginal design team David Newman said the rivet heads of an all-metal construction would have
cost them 20mph.
Cant speak for the absolute accuracy of that remark, but I also have no particular reason to disbelieve it either.
Just for general interest:
The Plane That Saved Britain: The Plane That Saved Britain - On Demand
At about the 10minuite mark, one of the orginal design team David Newman said the rivet heads of an all-metal construction would have
cost them 20mph.
Cant speak for the absolute accuracy of that remark, but I also have no particular reason to disbelieve it either.
There were (and are) fine makers of wooden furniture in the US; during WW2, there was also production of wooden boats, pianos, and wooden musical instruments. There are still a companies producing wooden aircraft propellers and wooden boats.
That said, the makers of large US aircraft had stopped manufacture of primary structure from wood, and would need time to relearn or learn those skills. For the relatively small number of Mosquitoes which were foreseen, the decision was made that this wasn't a worthwhile effort to get involved in: Mosquitoes would be obtained via reverse Lend-Lease, along with Spitfires and some other British aircraft. An aluminum Mosquito would be a completely new aircraft even if it looked like a Mosquito from a distance, it would take at least two years from project initiation to production. I also suspect that the Aluminum Mosquito would suffer badly from NIH syndrome, and the USAAF would insist upon massive changes to better fit their perceived needs.
Wasn't that an experiment to find which could be left as pop rivets without seriously harming performance?Spitfire test pilot Jeffrey Quill recounts how they prototyped a 'pop rivet' Spitfire by sticking a split pea onto the the many thousands of flush-headed rivets that covered the plane. They then test flew the plane, that was remarkably slower... some 22 mph , if I remember well.
Wasn't that an experiment to find which could be left as pop rivets without seriously harming performance?
In a similar vein, I don't know how many of you ever watched Mythbusters, but one of the episodes included covering a car with golf ball style dimples which made a noticeable improvement in the aerodynamics of the car. To do this, they covered it in clay and then impressed the dimples. While the car got heavier due to the clay it also got slipperier and improved gas mileage.Exactly. So they were able to progressively scrape off lines of peas, retest, and identify the critical areas. Many unnecessary lines of flush riveting were eliminated.