Science Interviews


Fri, 20th Jul 2012

From The Birth of Flight to the Great War

Peter Halford, Imperial War Museum Duxford
Charlie Taylor, Wright Bros. Engineer
Lieutenant Benjamin Folloy, US Army
Jerome Hunsaker, MIT
William Boeing, the Boeing Company

Listen Now    Download as mp3 from the show How Powered Flight got off the Ground

Ben - Flight had fascinated mankind for centuries:  In Greek mythology, Icarus attempted to escape from the Island of Crete on a pair of wings manufactured from feathers and wax; gliding flight was achieved with mixed success as early as 1010AD, and successful balloon flights were recorded regularly in the 1780s.  In my search for the birth of modern, powered flight, I visited the Imperial War Museum at Duxford, to meet Peter Halford and find out where to start...

Peter -  Well, way back in about 1870, something like that, when steam engines were being experimented with for powering aeroplanes, particularly flapping wing aeroplanes.  We’ve got an example here at Duxford of an engine which was used to power an experimental flapping wing aeroplane.  A very small engine, a Becker engine, 5 horsepower.  The problem with this, is of course, that not only was it made of heavy materials like cast iron, et cetera, you also had to carry water and fuel as it is external combustion engines so, not particularly successful for aviation.

Ben - So steam engines were not to be the source of power that took us off the ground.  But fairly soon, people were taking tentative steps towards take off.  The important difference was not so much the design, as the materials...

Peter -   Well, the main change was finding materials that would be strong enough, but light enough, so that you get a good power to weight ratio for an aeroplane.  We’ve just had some vintage cars here at Duxford such as Bentleys weighing about 2.5 tons with 200 horsepower engines.  That’s fine when you're on the ground, but when you want to lift your aeroplane up in the air, it’s not going to work.  So, that’s where the difficulties arise with aviation, not just for engines, but any of the materials and construction methods in an aeroplane have got to be advantageous for power to weight.

Ben - So big changes were afoot – and in 1903, Wilbur and Orville Wright made the first controlled, powered and sustained heavier-than-air flight.  A number of factors led to them claiming this hotly contested title...

First successful flight of the Wright Flyer, by the Wright brothers.Peter -   Well, two things.  The official point about this is that they had an independent eye witness and a photograph.  Other people at the same time, or around that time, in 1903 were experimenting with similar sorts of ideas, but unfortunately for them and for aviation history, they didn’t have the verifiable evidence which the Wright brothers had.  But the other thing was that they took from many, many sources, new ideas and technological advances.  One thing that they did, they were working with an engineer who developed an aluminium cylinder block.  So the materials were really important for this.  They could now have a relatively light engine to drive their aeroplane.

Ben - In the Early 1960s, The US Army caught up with Charlie Taylor, one of the engineers from the Wright Brother’s bicycle shop, as part of a documentary on the History of Aviation...

Charlie -   I made all the different parts in the motor, I even made the crankshaft.  I made it out of a solid block of steel about 32 inches long, 6 inches wide and 1 inch and 5/8 thick.  The motor itself - from the time I started 'til I had it ready for tests - was 6 weeks [work].  Fifty years ago but I can remember it as though it was yesterday almost.

Ben - And it’s not just the materials inside the engine that made a difference...

Peter -   They were using light woods.  The important thing with the wood was thast it was straight grained woods which would be very strong, but needed to be light, and had a fabric covering.  And this is where some of the problems with materials begin because if you put a fabric over a wooden frame, you can pull it as tight as you like, but if the atmospheric conditions are wrong, your fabric will become loose, the airflow wont operate properly, so you don’t get the lift that you were expecting.  The other problem is that you need a very, very tightly woven fabric so that the air won't flow through it, but over it.  The Wright Brothers discovered that ladies' underwear was the best material for this purpose.  Something called ‘Pride of the South’ which was a very tightly woven, but not very stretchy fabric.  Rather than using lots of ladies’ vests sown together, they had large sheets of this made to cover their aeroplane.  So, materials of all kinds have been very, very important right from the earliest stages.

Ben - And perhaps it was, at least in part, this reliance on underwear that stopped aircraft from being taken seriously by those who would soon come to rely upon planes - the military...

Peter -   The Wright Brothers successful flight was in 1903 and aviation hadn’t been on the, to use the modern term, the radar of the military at all.  In fact, they were reluctant to embrace the idea, going to the extent of saying, "these are new-fangled ideas", "it’ll never catch on", that sort of thing, which is absolutely typical of technological advance.  People just say, “Oh no, we do what we did before.”  Warfare had been conducted in a very similar manner for hundreds, if not thousands, of years.  So, the main method of moving things, transport, was animals, particularly horses, mules, et cetera.  And that’s how things were in the beginning of the First World War. The battlefield was very similar to what it might’ve been a hundred or more years before.

Ben - The Wright brothers, however, did see the potential in their machines, and set about proving it by showing off and setting world records.  Lieutenant Benjamin Folloy joined Orville Wright on one of these “show off” flights in 1908...

Benjamin -   On the day following the endurance test with Wilbur Wright, Orville, with a quiet little grin on his face, invited me to be his guest on the crucial and final cross country and speed tests.  On July 30th, we took off from the final cross country and speed test.  Shortly after we straightened out on the course for Alexandria, Orville, with this same little grin on his face told me that if he had to land anywhere on the route, that he would pick out the thickest clump of trees he could find and land on top of them.  Fortunately, the little engine that we had at that time carried us all the way through without any difficulty and we finally landed back on ground with three world records:  Cross country - 10 miles.  Altitude - 600 feet.  Speed - 42.5 miles an hour.

Ben - So what were the Wright brothers doing, erm, right?  It was not only the materials, but also their patented control system, and their rejection of flapping wings in favour of the propeller...

Peter -   All airplanes have propellers, but there are different types of propellers.  The popular understanding of a propeller is what we would now call an airscrew propeller.  So, that’s the rotating blades on the outside.  And the Wright Brothers used that.  One of their problems was that their engine wasn’t directly connected to the airscrews.  They were using chain drive from one engine to two propellers.  But the basics of that are the same as the physics for flight in general, using the airflow – air being the fluid, the fluid flowing over surface, and changing direction as something called the Coanda effect takes place.  So the air flowing backwards from the airscrew, the reaction to which, as Newton said, was a reaction forwards - thrust.  The same thing happens virtually with the aerofoil wing.  A curving surface, the air flowing over it and downwards, changes in pressure, and in fact, even now, at institutions such as the University of Cambridge still there is debate about exactly what's happening with the airflow over an aerofoil.  But suffice to say, it works.

Ben - These early flights were a good test bed to further our understanding of the physics of flight, which can be simplified to the laws set down by Isaac Newton – Every action has an equal and opposite reaction, so if you can push enough air towards the ground, it will push you into the sky.

Planes normally fly with their nose pointing slightly upward, so for air to get past the angled lower side of the wing it must be pushed downwards, while, due to a phenomenon called the Coanda effect, air sticks to the smoothly curved upper surface, and also ends up being forced downwards -  and so the plane is pushed up.

The engineering of flight caught the interest of universities, and soon became an area for academic study.  In the United States, the first Aeronautical Engineering department was headed by Jerome Hunsaker…

Jerome -   Professional education in aeronautical engineering again in this country at MIT in the winter of 1913 – 14, this course was started by President Maclaurin borrowing me from the navy department and supplying me with one assistant and staff who was a recent graduate in mechanical engineering, Donald Douglas from whom more was to be heard...

Ben - Donald Douglas then went on to establish the Douglas Aircraft Company in 1921, where they designed some of the most significant military aircraft of the 1940s.

Aeroplanes and their engines developed quickly through academic study, as well as the innovations of their designers, who were almost always their pilots.  They pushed hard to outdo each other and get further, faster, and higher.  But soon, global political events applied a different set of pressures...

Royal Flying Corps Sopwith Camel in 1914-1916 period."From a pistol shot in Sarajevo, the first of the great modern World Wars explode.  And almost overnight, all of Europe was engulfed in conflict.  The aeroplane was put to work as observation and scouting craft.  But in the air, alied and German pilots often waved to each other as they passed on their observation missions.  Then instead of a courteous wave, the opposing pilots began exchanging pistol fire.  Presently, the first crudely mounted machine guns appeared.  Now, the frantic race of inventing, improvising, adapting, and refining aircraft equipment began..."

Peter -   Initially, the use of aircraft in combat was more or less dismissed.  But it became apparent that they were going to be very useful for observing what the enemy was doing.  The First World War was taking place between two armies facing one another across an almost completely flat battlefield, dug into the ground.  Very, very hard to see what the enemy is doing.  So, if you can get up above them then you’ve got an advantage and that’s how the thing started, as observational aircraft.

Ben - Throughout the course of the war, many new engines were developed, with different designs, configurations and cooling systems...

Peter -   We’re standing here in front of the Le Rhône rotary engine, a very small engine, only about a meter wide or so.  It rotates around the central shaft.  So, the pistons are driving onto the central shaft to drive the airscrew propeller.  And the pistons themselves are rotating around.  An advantage of this is that of course, they're rotating in the air and they're cooling as they go around.  Cooling the engine is very, very important, it always has been.   If you can do it using air, then you're reducing the amount of kit you’ve got to take up with you and so, therefore, reducing the weight and increasing the weight to power ratio advantage.  Eventually, engines of this type could get up to about 280 horsepower.  Of course, along with the advantages, you also have some disadvantages and the disadvantage is one that it’s whirling round and round, and there's oil and things flying about all over the place, and the typical image of a first World War pilot is a blackened face with when he takes his goggles off, just white patches around his eyes.  A lot of that has to do with the muck that’s coming off of the engine as it’s whirling round and round.  Another problem, the larger it becomes, the greater mass you're whirling, and the harder it becomes to control your airplane because of the massive torque on here, trying to twist the airplane, so you have to compensate for that.  They were extremely popular in the first World War, relatively simple and light in comparison with others.  So, the first World War, many, many airplanes [used these engines] and a particularly well-known example would be something like the Sopwith Camel that used the engines of this nature.

Ben - Unlike the Le Rhône’s radial layout, the pistons of the Beardmore engine are aligned along the top...

Peter -   We’re standing in front of an engine from the 1914, the Beardmore engine and this would now develop 120 horsepower.  It’s a very beautiful looking piece of kit.  On the outside, it looks as if it’s made of copper and brass and indeed it is.  That’s the pipe work, copper being a very ductile material, very useful for making pipes, relatively easy to join, so what we can see on the outside is some lovely pipe work and then some water jackets around the pistons.  And this of course is where we were talking about the weight problem of having to carry this water to cool your engine.  Not only that, but the water leaks out, so there's lots of problems of that nature.  One of the points about an inline engine like this one is that its frontal area is relatively small  - the larger you get with both radial engines and rotary engines, the larger the surface area at the front is, which creates more drag.  Whereas with this one, you can make it a much more sleek and streamlined shape.  You’ve got everything fixed in place so you haven’t got this whirling around and round problem.  With a smallish engine like this one, the size of it and the length of it is not too great.  The more pistons you have and cylinders you have, the longer the engine becomes.  And then you have this difficulty of balancing your aeroplane because trim and balance on an airplane is absolutely necessary to get right which again, if you think of a land vehicle, using an engine similar as the one we’re looking at, it’s not such a big problem.

Ben - Another alternative, helping to pack more power into a shorter engine is to spread your pistons out into a V or W shape...

Peter -   So now, we’re standing in front of the Napier Lion.  The Napier engine was extremely successful.  This one is somewhat unusual as it's in what might be called a W formation.  Many people will have heard of V-shaped engines, but this one is a W, so it’s got cylinders coming in from the top and from the sides.  But that means that then you could have a shorter, much more compact, engine but with more cylinders, therefore, creating more power. 

Of course, during the first World War, many straight line and V-shaped piston engines we used, but as with other aspects of the war, there's an imperative for doing things and getting things done fast.  So, changes were taking place in an enormously rapid pace, much faster than they might have done if it had been completely peace time.  And so, the two things that were needed by the military were speed and manoeuvrability.  So with a powerful engine like this, you could climb faster, you could outrun your enemies, and so on.  So, that’s what the quest was for and engines like this were fulfilling that.

Ben - This pressure to provide faster, better aircraft to the war effort led to rapid development and mass manufacture, as well as a vast increase in the numbers of people trained to fly…

Peter -   Because there had been that large and quick development, there was also vast numbers of airplanes now surplus to requirement.  The First World War was dubbed "the war to end all wars".  The hope was that nothing like that would ever happen again.  So, these aeroplanes were available.  As with anything else - if you get something that goes fast, people want to race each other with them and so, that’s exactly what started to happen – air races were instigated.  There were even things called flying circuses and that’s where aviators went from town to town doing aerobatics and charging people to come and see them.  And of course, as soon as they had taken over the old fighters then they start to think, well, we could make this faster and faster, and then from that specific aircraft were being built simply for the speed aspect of things.

Ben - So the end of World War One changed the way we looked at flight and pilots and aircraft designers once more set about the peacetime challenge of outdoing each other.  Flight became a commercial enterprise, with flying circuses charging admission to wow the crowds with stunts, and some pilots carrying passengers or delivering packages.

William Boeing, founder of the Boeing Company, piloted the first international commercial airmail service in North America – delivering a parcel from Canada…

William -   In 1919, Eddie Hubbard and I took a flight up to Vancouver.  On our return trip, the postmaster of Vancouver gave us a mail sack for delivery to the postmaster at Seattle.  This was the first international mail ever carried by plane in the United States.

Ben - Back over here in Britain, people had the same idea about making money out of aircraft…

Peter -   Another aspect of the surplus airplanes from the First World War was that by the end of First World War, there were some relatively large airplanes, particularly for bombing, and people took those over, removed all the bombing apparatus and so on, and put a few seats in, and they became the first passenger airplanes or transport airplanes, particularly for carrying letters and newspapers to difficult to reach places such as the highlands of Scotland or the islands around Scotland.  So, all of that side of things was developing and in fact, of course, something called Imperial Airways began which is still going, it is now called BA.


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