Tag Archives: catalina flying boat

1985: MY PRIVATE HISTORY OF THE DAVIS-WING

I got interested (again) in aviation history when I bought thirty years ago at a jumble sale an old scrap book with photographs of the Dornier Do-X. The Germans have always been very proud of that boat, but of course in 1932 it failed dramatically where five years earlier Charles Lindbergh had succeeded without apparent effort: a simple non-stop jump across the Atlantic. I wondered why this could be so and started to read (+ collect) books about 1930-flying boats and airliners. What were the factors that determined their long-range performance? How fascinating that era was!
Next I got into a correspondence with a certain Don Middleton, a British aviation journalist, who had stated in an English monthly that the amazing long range of the Consolidated Catalina patrol boat was due to its ‘Davis-wing’. Based on general data from Jane’s ‘Fighting Aircraft of WWII’ edition I undertook to compare four contemporary transport planes: the Douglas DC-3 and DC-4, and the Consolidated Catalina and B-24 Liberator, and proved to him that Catalina’s extreme performance was based on two factors: its light construction (empty weight approximately 50% of take-off weight) and its slow cruising speed, which was right at the optimal economic flight point (maximum  CL/CD ratio). The other three planes, for commercial or operational reasons, all cruised faster than their most economic speed and as a consequence had a comparatively shorter range. The Cats were slow, real slow, to the exasperation of their crews. However, slowness could also be advantageous: they were able to shield the ships they were escorting by circling tightly around them, outmaneuvering in this way attacking German and Japanese aircraft that were much faster.

The PBY Catalina had no Davis-wing and I think I proved it, but Middleton never entered into a serious discussion and suggested I submit my paper to the Royal Aeronautical Society, which of course was a bit much. Later on I learned he disliked smart asses like me who argued from theory: he had been a skilled aircraft worker at de Havillands himself and a RAF engineer during the war.
Of course the Davis-wing was used on the B-24 Liberator. Next blogs will summarize what I know about it. The inventor, David R. Davis, [1] appeals to me because he was obviously a maverick: he worked outside the official circuits of Universities and NACA. Apparently he had a mind of his own. As a result however, descriptions of his work are hard to find in official literature (like Abbott & Doenhoff; maybe Durand mentions him?). Apparently his wing had extreme low drag at small angles of attack (laminar flow?), which is remarkable, because long range (like Catalina’s) is usually associated with low engine power and therefore relative large angles of attack. So there were things here which were not quite clear to me. I wanted to know more about the wing profile: it must have been very thin with maximum depth near the middle of the chord. How can thin wings be made strong enough for long spans? This was the state of my comprehension until I found more information.

[1] A word of warning: there have been other aviators of fame with the name Davis. So is our man not to be confused with the unfortunate pilot Noel Guy Davis, who crashed short after take-off for a trans-Atlantic flight in 1927, aboard a Keystone Pathfinder (N-X179) airplane called American Legion.
[2] picture: PBY5 Catalina; credit: Wiki.

Advertisements

LADDON’s CATALINA

404px-Isaac_Machlin_Laddon_(4728516487)a

I am posting today on my site a page that describes the history of the design effort of ISAAC MACHLIN LADDON to create that remarkable flying boat, the PBY CATALINA.
Press the tab at the top of the screen or you can download the story directly from here:
LADDON CATALINA

CREATING THE PERFECT AIRPLANE

 pby-5_catalina

Soon I plan to deposit on this website the story of Isaac Machlin Laddon and his superb creation the
PBY Catalina flying boat.

In 1934 he obtained with this airplane form that was perfect­ly matched to function.
He was so happy with it (rightly so), that he patented its shape, like Coca Cola had done with its bottle. Especially pleasing to the eye was the mounting of the high parasol wing on the fish-like hull. An original supporting structure was used; its origin puzzled the experts.

 Roscoe Creed wrote:  “…Laddon’s choices were:
–  to use struts to mount the wing as before,
–  or resort to a deep hull with a shoulder-mounted wing,
–  or a less deep hull with a gull-wing,
–  or set the wing on a pylon…
Just how and when Laddon came up with the pylon idea nobody knows…”

The article that I will be posting shortly under ‘PBY CATALINA’ pretends to give the answer.

GOING A LONG WAY

Zero A6M5_Aleutian

Somehow the real theme of this website seems to be
long distance flight in the last century.
Today I am posting the page ‘ZERO MYTH’ by my friend Roy Day about the Japanese Zero fighter that could fly 2000 miles.
There were rumors that it was invincible…
Until one day in 1942 a PBY Catalina came across a shot-down Zero in the Aleutians..
ZERO MYTH

Read also the remarkable companion story in Sport Aviation.
(Link provided.)