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The Loftsman
 
 
 
 
Leith Shipyards

A history of the Ships built at the Henry Robb Shipyard in Leith, Scotland. Also a testimony to the men who built the Ships and to all who sailed in them.
 
     
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 Aircraft Lofting

The use of lofting in the design of Aircraft really took off for want of a better description during World War II when some well documented efforts made a huge difference to the look and performance of new aircraft development and not to mention the use of conical lofting in the development of one of the most successful fighter planes of World War II namely the P-51 Mustang.

p51mustang_photo-from-Boein

The classic Lofted lines of the P-51 Mustang seen here in a Boeing photograph.

The story of the Mustang development will be continued.

 

Below is an interesting story on lofting as used by the Bell Aircraft Company during World War II.

 Or, how Lofting contributed to the first B-29 raid on Japan.

Northwest Georgia report in June 1943 indicated that during the previous year 969"boys and girls from 26 northwest Georgia counties" had completed training under their War Production Training Project. Of that total, 441 males and 175 females were placed in war production jobs.
It appears the early plan for existing schools to handle the intensive training
needs was overly ambitious and new training programs were needed. In November 1942, the Cobb County Board of Education opened the new Rickenbacker Aircraft Training School in buildings abandoned by the Civilian Conservation Corps, using a $5,000 donation from Eddie Rickenbacker.

After Bell occupied the plant in 1943, extensive training programs were carried
on in the plant where scrap metal was available to teach skills such as riveting, working sheet metal and welding.
B-29s built at other Boeing plants were flown to Marietta and used to give new workers on-the-job training. By September 1943, when thousands of new workers were being hired, Bell had 25 training counsellors employed at the plant.

Manufacturing the B-29 required skills that were new even to experienced aircraft plant workers because the design of the plane incorporated innovations for improved aerodynamic performance, such as butt jointing sheet metal parts, as opposed to overlapped joints, and flush mounted rivet heads.

Creating sheet metal parts and assembling them into complex shapes was
one of the primary work requirements and, while experienced aircraft builders did this work with pride, training new workers in these difficult tasks was a major challenge for Bell.
One approach unique to the Bell plant among the four B-29 plants was the use of lofting. Lofting was a system that produced drawings of airframe parts that were full-scale, and these huge drawings were used to create templates that were used in turn to set up tools and manufacture dies.

 B29_Bomber

The Boeing B-29

The Bell engineers indicated that lofting was"...now considered the backbone of Bell's aircraft manufacturing methods" and they insisted on using this approach instead of having Boeing supply templates to Marietta Georgia.
Lofting personnel ("loftsmen") were highly specialized draftsmen, of
which there were few to be found in Georgia (Bell had "borrowed" their lofting system from the shipbuilding industry, and Georgia had neither large shipyards nor aircraft manufacturing in 1943).
To train the essential loftsmen, Bell sought workers who they thought could master lofting after an intensive 5-month training program at the Bell plant in Buffalo.

The loftsmen hired in Georgia included a professor, a sculptor and a pattern maker from the chenille bedspread industry.
The first B-29 raid on mainland Japan took place in mid 1944.

 The following is an example done on CAD of a Spitfire wing, this is for a model of the world famous Spitfire.

 

 The use of descriptive geometry has of course been developed over time in Aircraft Lofting, but is interesting to look back on and just as this

photograph shows (which looks posed for the camera) was still a very complex and involved skill as seen in the layout of the huge delta shape

that outlined the wing of the British Concord.

 

 

 

 Lines fairing of a small boat. (photo credit unknown) P.S. the Loft weights (or splines or ducks) are positioned wrong in this photograph.

 

So I hope that this is given you some idea of what a Loftsman does, be it Ships, Aircraft or Automobiles anything that has shape and is required to move, needs to be lofted, and I dont give a monkeys what fancy new name's they give to it. It is still Lofting. Descriptive Geometry is descriptive geometry be it laid out full size or on a computer screen. (How many of todays HR departments would have a clue - perhaps some are now en-lightened)?

Also very interesting to note that if you look at some of the more advanced modern structures built recently such as some of the "Guggenheim museums" you will see lofted surfaces now being used in this industry.

While by no means complete (it would need a few book volumes) you will also see that no matter what some say nowadays it really is a pretty specialised craft, no magic involved just bloody hard work, but most enjoyable and satisfying for any one who has been fortunate to have worked as a Loftsman or woman (to be P.C. nowadays)

I do find it a wee bit strange that in these days of high fuel costs and eco friendly times that the old rules of an aesthetic shape which creates the least resistance be it in water or air (which is in fact very much like water) is the most economical shape to run, but not necessarily the cheapest form to manufacture so again it all comes down to money and profit. If it looks good, then more times than not it is good.

 

Below is an interesting acknowledgement to Shipbuilding and Lofting from a couple of Giants of the Automotive Industry in the United States who produced a critically acclaimed book on Automotive Design, its origins and use for a Century of designing classic Cars.

 A CENTURY OF AUTOMOTIVE STYLE

100 Years of American Car Design

By Michael Lamm and Dave Holls

This 100-year history explains why cars looked, and look, the way they do, who designed what, and why. The original hardcover book was voted “must have” by major enthusiast magazines in the U.S. and Europe. The book also won the Society of Automotive Historians’ prestigious Cugnot Award.

The book is now out of print, but you can enjoy the DVD as one of the world’s best automotive reads and then keep it in your library for handy long term reference. The DVD contains the original book in its entirety: 308 pages, more than 900 photos, complete text, captions, sidebars and index. Nothing’s left out. The disc is fully searchable and very easy to use. The DVD remains the “book” of choice for everyone interested or involved in the history of car design.

Excerpt from the book.

This short selection from the beginning of the book defines the origins of a few of the body design terms studios use in creating surfaces.

It all goes back to shipbuilding

It’s no big secret that a lot of early motorcars took their body design from carriages. But it’s less obvious that carriage design evolved from shipbuilding. As with so many other arts and crafts, it all began with the Greeks.

In the 19th century, archaeologists discovered mysterious lines scribed on the floors of Roman temples. What did these odd lines mean? The scholars discovered that they were the outlines of huge Roman ships, drawn in plan view (plan view means “as seen from directly above”). The smooth temple floors made an ideal surface to loft a ship’s hull full size.

The Greeks, Norsemen, Southeast Islanders and even some tribes of American Indians used a variation of this same idea. They would draw a full-sized hull outline on a sandy beach, plant sticks around the perimeter, and then connect the sticks with thongs. Finally they’d string more thongs diagonally across the hull to indicate the ship’s ribbing. The resulting “blueprint,” crude as it was, be-came the working drawing for a trireme, a packet or a war canoe.

These techniques worked well enough for the ancients, but as ships grew larger and more complicated, the blueprints had to be refined. For one thing, a simple plan view drawing gave the shipwright only a two dimensional, incomplete map to work from. What he really needed was a set of plans that showed in a way that workmen could read and follow.

So in the 1600s, European ship designers came up with a system for representing all three dimensions on a flat sheet of paper. This system involved basic geometry. Automobile stylists still use it today to map out autobody surfaces, but they now let computers do the mathematical calculations.

Once a ship’s designer had the ability to indicate to the carpenter or shipwright exactly how the finished hull ought to be constructed, style started to enter the picture. Ships evolved from the tall, ungainly craft that sailed the ocean blue in 1492 to the sleek clipper ships of the mid-1800s. Amazingly, in that transformation, the fundamentals of ship-building didn’t change. What did change was that the ship designer-call him “stylist”-could and did get involved in the building process.

It’s easy enough to see that the design system that evolved for ships’ hulls carried over first into carriage building and then into auto body design. In the 18th and 19th centuries, the first step in designing a ship’s hull meant carving a scale “half model” from wood. A common scale was one inch to four feet, or 1/48. And the half model was exactly what it sounds like: not a representation of the entire hull but just half of it, split vertically down the middle and flat from the keel line up. This half-hull model was usually carved from a stack of planks, or layers. The planks fit tightly together, one atop the other, and they were held in place with tapered pegs that fit into vertical holes. The model did not have masts or sails.

Sections were taken at specific intervals and transferred to full-size drawings on the floor of the shipbuilder’s loft.

Once this scale half-model was approved, the master builder would take the half-model planks apart and use the individual slices to make sectional full-sized drawings. In other words, the separate sections (planks) were all scaled up, or “lofted,” to full size. (The verb to “loft” grew out of shipyard parlance, because the only place where a ship builder’s shop had enough room to lay down the scaled-up outlines of a full-sized ship’s hull-enough clear floorspace, as in those Roman temples—was usually in the loft: the attic above the boat works. This was also the area where, at other times, most of the sails were cut and sewn.)

In the shipyard loft, the “loftsman”—the person in charge of scaling up the half-hull model—would first draw out the lines of each hull section and then, from those drafts, make full-sized templates, or “molds.” The ship’s carpenters and craftsmen in the shop below then used these templates to cut and size the wooden beams that formed the ship’s main framework. By using the same templates first on one side of the hull and then the other, the two halves of the finished framing came together as mirror images.

 

Now it’s important to recognize that any mistake the hull designer or the master builder might have made in his original scale model got magnified, often by a factor of 48 or more, when that model was lofted full size. And since any scale model always did contain surface flaws, it was up to the loftsman to “fair” the full-sized representations. Fairing meant, first and foremost, making an ungainly or flawed design efficient as it moved through the water. Fairing meant smoothing the surface, sculpting the lines, reshaping, streamlining the hull, because a smooth, streamlined hull made the ship go faster, and speed meant money. Speed made the ship more profitable. So profit became the main motive for fairing a hull.

But fairing also had an aesthetic component. The art of fairing meant that the loftsman had the authority to change the full-scale drawings and templates so the lines looked “right;” so that the hull had what was generally accepted as a “proper” shape. The hull should look pleasing; it should look graceful and “fair,” as in “a fair young maid.” A good loftsman had an eye for fairing, and his aesthetic sense was as critical to the design process as his ability to make the hull efficient. Fairing, then, became the act of combining efficiency with beauty.

In the scaling-up process, the loftsman had the authority to “fair” or smooth out any irregularities in the hull shape, both in terms of fluid dynamics and aesthetics. He thus became the final arbiter of the ship hull’s styling.

And now we make that leap that allows us to recognize that the same techniques and processes used in ship design carried over into horse drawn vehicles. Carriages, like ships, needed to be efficient, but efficiency in this case didn’t mean streamlined; it meant light weight. A carriage had to be light. That’s because there was only from one to four horsepower to pull it.

Unlike ships’ hulls, the designing of carriages was almost never preceded by a scale model. It’s possible that a few carriage makers did use models, perhaps made of wood or sculptors’ clay, to help customers visualize what they were buying. But models weren’t common in carriage design, even in Europe. Rather, what carriage builders did was to first make detailed sketches, usually 1/10 or 1/12 scale, and the loft those sketches full-size on big, upright wooden panels.

To save space, the technique of lofting a carriage involved drawing a side view and then also superimposing half of a plan view on top of it. Both views were crammed onto the same board, and the drawings were kept separate and readable by being done in different colours. Offsets were called out on separate sheets of paper, and sometimes templates were made for the carriage body, but mostly not. This same technique evolved into the design and construction of automobile bodies and was used well into the 1980s. Note:- The three ships views were all superimposed on top of one another to save space, only the full size Body Plan was drawn out seperate in ship lofting to form the scrieve board.

“While some of the above may call out a little, shall we say artistic licence, if it is to be made and constructed by man then it needs to be Lofted. Ship, Aircraft or Automobile, in fact anything that has shape and form to be constructed first has to be Lofted, they give it many different names today but it is all Lofting”.

 To be continued, perhaps we will look into the subject of "Whole Moulding" next

And as always if you have any comments, advice or photographs then please feel free to contribute. 

 

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Comments   

 
0 #8 George Lamb 2017-04-20 18:13
I visited this web site many years ago. It has certainly been added to since then.
I served my apprenticeship at Charles Connell of Scotstoun, Glasgow.
I started there in 1950 and left in 1961.
I went to Vickers Armstrong Aircraft in Weybridge, Surrey as a loftsman to work on the design for the "TSR2" fighter then on to the "VC10" and "Concord".
I went to Germany to work on the "Airbus A300B".
I went to Canada to work on the "de Havilland Dash 7".
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+2 #7 Peter Wallace 2014-03-14 22:17
Have just discovered this excellent site! I have a special interest since my grandfather was the William Wallace mentioned in Gerry Finlay's blog#6. Look forward to the expansion of the site. Good luck!
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+2 #6 Gerald Finlay. Gerry 2013-12-20 02:02
I served my apprenticeship in Henry Robbs from April 1949 until February 1955, my first year was a Loft helper to a journyman, The Foreman was William Wallace, the assistant Foreman was George Ewing, the jourmyman was James Love, Joe Alexander, George Powrie, William Tweedie, Robert Wise, 5th year apprentice was Douglas Hogg, 4th year apprentice was Peter Rennie, 2nd year Apprentice was James Foulis, 1st year Apprentice was Hugh Anderson, this was all the loft staff in 1949. at the moment I am writing out my experiences as a Loftsman and what my speciality was in the trade.
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+2 #5 Kirk Bready 2013-03-29 15:55
My Dad, a third generation shipbuilder, was a mold loftsman starting in 1940 at the Bethlehem Steel Ship Repair yard in Baltimore, MD. I was always mystified by the problem of producing a precisely formed hull that curved continuously in every dimension. My curiosity was not helped by the fact that when I was a youngster his explanations went right over my head. Therefore, it was a joy to find this terrific article which has enabled me to more fully understand and appreciate what he and his peers accomplished.

As U.S. shipbuilding declined, my Dad wound up at a company in Memphis, TN that fabricated large industrial vessels but had limited capability with complex structure. There he introduced & set up a mold loft department that enabled them to expand their capability and market. They were very generous in expressing their appreciation. Thanks to this article, I can now understand why.
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+4 #4 peter rennie 2012-08-09 19:16
Hi
My father was a loftsman in robbs spent all his working days at the yard.

Thanks
Peter Rennie jnr.
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0 #3 Gordon Sanstad 2011-03-23 18:15
Dear Sirs/Mdms:

I am looking for a history of lofting. Anyone know when and where it was first used or developed (in the construction of boats, I assume the first use)?

Thank you,
Gordon Sanstad
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0 #2 MOHAMMAD ALI Asgar 2011-03-04 20:45
I am specilized on lofting works from small scale drawing to Lrgae scale full drawing 1:1 , making body plan, templaes for fabrication, bending, plates cutting and ships block making erection dhechking etc all fro lofting to Hull erection and superdtructure works also.
i have done one Rig ship selfpropelled in AHI, Ajman for Bibby shipping line, name Trident Bibby [1 working in Qatar Oil field.This is great website,thank you.
THNAKS,
ENGR.MOHAMMAD ALI
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+2 #1 Billy Blair 2011-02-15 14:19
Fantastic find, I was an apprentice loftsman at Henry Robb 1980-1984. I look forward to any updates.
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