23 (iii) Modesty, thy name is Professor J. B. Pettigrew

"To Professor J. Bell Pettigrew is due the merit of having first satisfactorily analysed [wing] movements, and of having reproduced them by the aid of artificial wings. This physiologist in 1867 showed that all natural wings, whether of the insect, bat, or bird, are screws structurally, and that they act as screws when they are made to vibrate, from the fact that they twist in opposite directions during the down and up strokes. He also explained that all wings act upon a common principle, and that they present oblique, kite-like surfaces to the air, through which they pass much in the same way that an oar passes through water in sculling. He further pointed out that the wings of flying creatures (contrary to received opinions, and as has been already indicated) strike downwards and forwards during the down strokes, and upwards and forwards during the up strokes. Lastly, and most important of all, he demonstrated that the wings of flying creatures, when the bodies of said creatures are fixed, describe figure-of-8 tracks in space, - the figure-of-8 tracks, when the bodies are released and advancing as in rapid flight, being opened out and converted into waved tracks.

Professor Pettigrew's discovery of the figure-of-8 and waved movements, concerning which so much has been said and written, was confirmed some two years after it was made by Professor E. J. Marey by the aid of the "sphygmograph."

from FLIGHT, FLYING MACHINES in volume 9 of the Ninth Edition of Encyclopaedia Britannica. Author : Professor J. B. Pettigrew. Including credits to illustrations and tables, I count no fewer than 45 named citations of the illustrious academic, which must surely be some kind of record.

It is a great shame that for all the time and energy the professor invested in the study of flapping, not a single flying machine following that model has ever sustained flight. Perhaps surprisingly, J. B. P. was not entirely blinkered in his view of the problem of flight, and although containing a great deal on the subject of flapping, his article does eventually move into other areas.

"In flight, one of two things is necessary. Either the wings must attack the air with great violence, or the air in rapid motion must attack the wings : either suffices. [...] The flight of the albatross supplies the necessary illustration. If by chance this magnificent bird alights upon the sea he must flap and beat the water and air with his wings with tremendous energy until he gets fairly launched. This done he extends his enormous pinions and sails majestically along, seldom deigning to flap his wings, the breeze works for him."

The article continues at length, describing with enthusiasm projected and attempted models, in many (but not all) of which some kind of flapping motion is a key feature. It would be far fairer to Professor Pettigrew to reproduce his text in full : however fairness is not my object at this time, so we will finish with the professor's final, patriotic words, and do our best to forget two bicycle-salesmen brothers from Ohio.

"The unremitting efforts of Mr Moy and other British engineers to construct flying machines deserve well of science. They are significant as showing that the great subject of aerial navigation is at length receiving a fair share of the thought and energy of a country which has already produced the locomotive engine, and which, there is good reason to believe, is destined also to produce the flying machine."

[You can now enjoy the article FLIGHT, FLYING MACHINES in full at the 1902 Encyclopedia, complete with all illustrations.]

23 (ii) A physical problem to be solved by mechanical skill and ingenuity

"FLIGHT, FLYING MACHINES. Of the many scientific problems of modern times, there are few possessing a wider or more enduring interest than that of aerial navigation. To fly has always been an object of ambition with man ; nor will this occasion surprise when we remember the marvellous freedom enjoyed by volant as compared with non-volant animals. The traditions of Daedalus and Icarus illustrate the attempts in the past ; and at the present day societies exist in Britain, France, Austria, and other countries, for the purpose of solving, if possible, the knotty problem. These societies embrace men of the highest scientific attainments, and as they evince great activity, and publish their proceedings at regular intervals, it is not too much to expect that the problem of artificial flight will be actually solved, or at least much simplified. For the first time in the history of the world, the subject of aerial navigation has been taken up in earnest by practical men with the necessary degree of preliminary knowledge and training. Investigators no longer dream about flight : they experiment upon and work towards it. It is, they maintain, a physical problem to be solved by mechanical skill and ingenuity. But while writing thus hopefully, it is necessary to state that as yet no one has succeeded in constructing a fully equipped flying machine. The number of successful flying models, however, is so considerable as to inspire the cultivators of aeronautical science with a very confident hope of success."

So begins Professor J. B. Pettigrew's delightful and compelling essay, a companion to AERONAUTICS in EB9's first volume, available for your perusal at our old friend 1902encyclopedia.com . [As is FLIGHT, FLYING MACHINES in full now, complete with the illustrations in their original, undistorted context]. The thrill and excitement of man's incipient conquest of the air hums from the very pages. There are many charmingly potty allusions and speculations, but the writing is clear and informative, and conveys to the reader a great and insight and appreciation of the particular problem.

"The subject of aerostation is admitted on all hands to be one of extreme difficulty. To tread upon the air (and this is what is really meant) is, at first sight, in the highest degree utopian ; and yet there are thousands of living creatures which actually accomplish this feat. These creatures, however varied in form and structure, all fly according to one and the same principle ; and this is a significant fact, as it tends to show that the air must be attacked in a particular way to ensure flight. The flying machine of the future, there can be no doubt, will be constructed on the type of flying animals, - the insect, bird and bat. It behoves us then at the outset to scrutinise very carefully the general configuration of flying animals, and in particular the size, shape and movements of thei flying organs.

Flying animals, it may be premised, differ entirely from sailing ships and from balloons, with which they are not unfrequently though erroneously compared ; and a flying machine constructed upon proper principles can have nothing in common with either of those creations."

It would no doubt be of satisfaction to the professor to learn that in the 21st century, comparisons between flying creatures and boats and balloons are now happily unfrequent.

There follows a discussion of the similarities and differences between those creatures and objects which move through water and through the air. Professor Pettigrew is contemptuous in his dismissal of the balloon, inferior to both the ship and the true flying machine in its inability to steer : it is a "mere lifting machine." His assertion that the "force required to propel a balloon against even a moderate breeze would result in its destruction" would of course later be disproved by the invention of the airship ; it is difficult to dismiss the notion that the spectacular demise of that particular form of aerial navigation would have caused the professor no small degree of schadenfreude.

Balloons operate by being being lighter than the air and so rising, passively - but weight and power are discovered to be the secret of the true flying machine, which

"need not necessarily be a light, airy structure exposing an immoderate amount of surface. [...] It should attack and subdue the air, and never give the air an opportunity of attacking and subduing it. It should smite the air intelligently and as a master, and its vigorous well-directed thrusts should in every instance elicit an upward and forward recoil. The flying machine of the future, there is reason to believe, will be a veritable example of "multum in parvo." It will launch itself in the ocean of air, and will extract from that air, by means of its travelling surfaces - however fashioned and however applied - the recoil or resistance necessary to elevate and carry it forward."

Rousing stuff, professor!

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