Author Topic: Breguet AG.4, early September, 1914  (Read 11344 times)

Offline Old Man

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Breguet AG.4, early September, 1914
« on: May 07, 2012, 11:00:16 AM »
I have wanted for some years to do a model of this particular aeroplane, and have only recently come upon sufficient information to take a decent run at it. It was a wretched flying machine, a dead-end developmentally, and had a very brief and limited service life, but it flew one of the most significant sorties ever flown by any aircraft.

M. Louis Breguet was working on two designs when the Great War broke out, one a tractor and one a pusher, both designed to meet a specification issued by the Aviation Militaire in late 1913 for armored aeroplanes. The tractor, employing a high-power twin-row Gnome rotary, was designated AG.4, the pusher, employing a twin-row Canton-Unne radial, was designated BU.3. One example of the tractor had been completed by early August, components for another, and for the pusher, were in hand but not yet completed and assembled.

M. Breguet had realized during 1913 that his original tractor design pattern, with single spar wings employing warp-control, conical rear fuselage, and an all-flying, cruciform tail surface, had reached the end of its potential, and had  begun designing a twin-spar wing structure which employed ailerons, which he fitted to a pair of racers that year, though these continued with the older fuselage and tail surfaces. The AG.4 incorporated this wing structure, with more conventional, though still all-flying, tail surfaces, and a new fuselage with a squared off structure topped with a standard turtle-back. The result, though able to carry a good weight aloft, like all Breguet designs, was a poor flyer, with poor directional stability, and further hampered by the flaws of the twin-row Gnome rotary, which was a lamentably un-reliable device, however useful it might be, when carefully cossetted and pampered, for bursts of speed at racing meets (or official trials).

As the German advance into France neared the Breguet factory at Douai, M. Breguet flew the completed AG.4 to Paris, placing it and himself at the disposal of Fortified Camp the city had been designated (the components of the other AG.4, and of the BU.3, made the same trip on trucks by road). The Gnome threw a rocker-arm during the flight, but now Cpl. Breguet was fortunate no structural damage was sustained, and managed to keep control of the machine.

On Sept. 2nd, Cpl. Breguet, with Lt. Watteau as observer, flew his AG.4 (it was still his property, not Aviation Militaire equipment) on a long-range reconnaissance from Paris during which Lt. Watteau detected the first signs the German general von Kluck was turning his forces to pass to the east of Paris rather than to the west of it. This report, brought to Gen Gallieni in Paris, was the germ from which the great riposte of the Marne sprang, which forced the German retreat and ensured the hostilities would be no decisive summer campaign but endure for years and set the shape of the whole ensuing century. Because of this the AG.4, however poor its qualities as a flying machine or a service machine, and however brief its use, is owed a very significant place in aviation history.

Shortly after this flight, the AG.4 was accepted by the Aviation Militaire, and given the serial number BR52. It was equipped with a Hotchkiss machine gun in the observer's position, and sent to Escadrille BR.17, equipped with earlier single-spar Breguet designs and operating in Alsace. While there its pilot, Lt. Moineau, a test pilot for Breguet in peace-time, fitted it with a triangular fin and a larger rudder, in an attempt to address its poor stability. It was not wholly successful, and the twin-row Gnome motor gave tremendous difficulties in the field. When the unit re-equipped with Voisins near the end of October, BR52 was abandoned.

The components of the second AG.4 were assembled in October at Paris, fitted with the same fin and an even larger rudder, and taken on by the Aviation Militaire as BR53. Armed with a Hotchkiss machine-gun, it was flown on defensive patrols, with an eye towards engaging any German aeroplanes or Zeppelins flying towards Paris. In this role it received some news-paper coverage claiming it had engaged German Tauben and Aviatiks on several occasions, but this is probably untrue, however comforting it may have been to read in the city. After a series of forced landings, including one on the day after Christmas, 1914, BR53 was written off, sometime around the end of the year.

M. Breguet attempted to salvage the design by fitting a third air-frame with a twin-row Canton-Unne, and fairing out the fuselage to round section with light stringers, but without success. The single example, on trial with the French Navy, crashed on landing after a bombing raid in February of 1915. The Breguet concern was by then devoted to producing pusher bombers, derived from the BU.3, in company with Michellin freres.



Here is pretty much the sum of the available material to guide this build:



This is the only photograph I have been able to find showing the AG.4 flown to Paris by M. Breguet in its original form (scanned from Warplanes of WWI, Fighters, vol. 4, by J.M. Bruce).

Here are two photographs of the second example, BR53 (the first scanned from the above source):





Here, for interest, is a newspaper photograph (probably of BR53) from the period, with some obvious retouching by the censor:




Here is a drawing in general circulation: it has some good points, but I do not trust it, and of course it shows the late tail assembly:



Here is a period drawing from 1914, of a 'Breguet  2 Seater Armoured Biplane': it is not wholly accurate either, but has many useful points, including stated dimensions:





Obviously, there will be a certain 'seat of the pants' quality to this build, but I expect I will be within spitting distance of the real thing when completed, at least....
« Last Edit: May 07, 2012, 11:06:14 AM by Old Man »

Offline Old Man

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Re: Breguet AG.4, early September, 1914
« Reply #1 on: May 07, 2012, 11:15:05 AM »
I have gotten underway with this over the last couple of weeks.

I usually wind up beginning with the wings, which, though laborious, are fairly simple.

The starting point is two long rectangles, in this instance of 1mm sheet (as Breguet wings were pretty thin). To get the camber, they are scored deeply and bent, then the open groove is filled with CA glue. The first picture is the upper surface, the lower is the undersurface.





Here are the tools I use past this point:



All of these have sand-papers of various grits attached with double-faced tape. The flat tool, a length of yard-stick, is used to smooth and curve the upper surface; the bottles are used to smooth the under-surface with its concave camber. I use heavy cutting grits for this, 180 and 220. The length of dowel is for taking down the space between ribs, and the edge of the curved blade is the follow-up here. The dowel is easier to control than coils or folds of sand-paper, and leaves a better initial surface than starting out by scraping with the blade's edge.





Here are both wings, in their final shapes, with ribbings marked and set in. The heavy lines mark the ribs that will be taped (every third rib was sewn in tape). The piece that has no ribs marked in its center section will be the lower wing: its center section will be cut out, as there was only bare spar here on the AG.4.

Offline Old Man

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Re: Breguet AG.4, early September, 1914
« Reply #2 on: May 07, 2012, 11:16:18 AM »
Here are the wings with their trailing edge scalloping put in (using a half-round needle file.



For rib-tapes, I am using 1/64" pin-striping tape. Here is start of the process on the upper wing under-surface. Its dihedral has already been put in, by scoring at the ends of the straight portion of the cut-out.



This tape is interesting to use, but I have high hopes for the technique. It is so insubstantial that the static electricity generated by lifting a length of it from the reel will pull it down to the surface of the wing-piece.

Here is the upper wing with all ribs taped, and the whole sprayed with two heavy coats of Tamiya fine white primer.





I want to have the lower wing split and set on its bare spars before taping its ribs.

Offline Old Man

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Re: Breguet AG.4, early September, 1914
« Reply #3 on: May 07, 2012, 11:17:31 AM »
Here are some pictures of the lower wing, in just about finished state. It has been split, the panels linked by bare spar, and the rib tapes in place and covered with a heavy coat of rattle-can primer.






The forward 'spar' section is steel, from a paper clip; the rear one one is .9mm styrene rod. Though secure, the thing is definitely wobbly, and in working on it, I use the upper wing as a sort of support cradle...



This is going to affect construction procedure. I am going to have to view things as being suspended from the upper wing rather than built up from the lower wing, and I expect I will assemble the wing cell first, then insert the fuselage (when built), attaching it to the upper wing first.

I will be giving this a bit of a rest now, as I am awaiting arrival of ICM  Fokker and Pfalz E.IV kits. These types employed a fourteen cylinder Gnome of the same dimensions as the one employed here, and I want the motor in hand before I tackle fuselage dimensions, and try and decide if the motor on the AG.4 was geared (I suspect it might have been). I do not know if I will simply pirate one of the motors, or use one as a model for fabrication, or even try some casting in silicon block with the piece or pieces as a master.

So I expect, anyway, to be devoting my next couple of modeling sessions to another project that has been hanging fire a bit, a Curtiss P-1 in Chilean service, for a group build ending on June 10 on ARC. This is a pretty late start, but I have done a lot of Curtiss fighters, so I figure I still have a chance to make the deadline there.

Offline Des

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Re: Breguet AG.4, early September, 1914
« Reply #4 on: May 07, 2012, 12:14:41 PM »
Excellent start on your scratch build, this is a very interesting subject you have chosen and I will be following your progress closely.

Des.
Late Founder of ww1aircraftmodels.com and forum.ww1aircraftmodels.com

Offline RAGIII

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Re: Breguet AG.4, early September, 1914
« Reply #5 on: May 07, 2012, 12:45:54 PM »
Your wings have turned out beautifully! looking forward to the remainder of your build and seeing how you overcome the challenges you have mentioned in construction.
RAGIII
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"Don't slop it on" Lynda Geisler

Offline ALBATROS1234

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Re: Breguet AG.4, early September, 1914
« Reply #6 on: May 07, 2012, 01:50:23 PM »
very nice , i like how you approached the wings.

Online Whiteknuckles

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Re: Breguet AG.4, early September, 1914
« Reply #7 on: May 08, 2012, 09:24:35 AM »
Nice work old man and an interesting subject!!

Andrew
Eternal Apprentice

Offline GAJouette

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Re: Breguet AG.4, early September, 1914
« Reply #8 on: May 08, 2012, 11:14:31 PM »
Old Man,
Outstanding project to date my old friend. Very impressive wing construction method that I'm wondering how well the same would work in 1/32 scale. Looking forward to the next update and learning additional tips and techniques from you.
Highest Regards,
Gregory Jouette
" What Me Worry"

Offline phs Paddy

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Re: Breguet AG.4, early September, 1914
« Reply #9 on: May 08, 2012, 11:56:08 PM »
Love to follow these scratch builds. Always informing and a joy to watch the craftsmanship.

Paddy
In mathematics you don't understand things, you just get use to them. Johann von Neumann 1903-1957

Offline ALBATROS1234

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Re: Breguet AG.4, early September, 1914
« Reply #10 on: May 11, 2012, 02:31:00 PM »
and old man is a master as such things. his 1/72 scratchbuilt stuff is second to none. very thorough detailing.

Offline coyotemagic

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Re: Breguet AG.4, early September, 1914
« Reply #11 on: May 15, 2012, 03:36:43 AM »
Another masterpiece in the making.  Love the esoteric subjects you choose.
Cheers,
Bud
"All men dream: but not equally. Those who dream in the dark recesses of the night awake in the day to find all was vanity. But the dreamers of day are dangerous men, for they may act their dreams with open eyes, and make it possible." -T. E. Lawrence

Offline ta152c

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Re: Breguet AG.4, early September, 1914
« Reply #12 on: May 15, 2012, 09:18:17 AM »
Such a delight to see simple tools making such delicate shapes -bravo!

Regards :)
"I hope he burned all the way down" - Mannock on hearing of the death of Manfred Von Richthofen, 1918.

Offline GAJouette

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Re: Breguet AG.4, early September, 1914
« Reply #13 on: June 05, 2012, 02:24:13 AM »
   Old Man,
Long time no see updates my old friend. How's the little Gem progressing ?
Highest Regards,
Gregory Jouette
" What Me Worry"

Offline Old Man

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Re: Breguet AG.4, early September, 1914
« Reply #14 on: June 23, 2012, 02:08:45 PM »
I am just about finished with the Chilean Curtiss project I put this build aside to deal with (as it had a group build deadline).

I am now working on the fuselage of the Breguet....

I am doing the fuselage in front and rear sections.

The forward section began with a square front piece. The fuselage tapers back from the front, but tapers more sharply at the very front. Short side-pieces of 1mm thickness were put in place for the area of sharper taper. A solid front decking of 2mm and 1mm sheet laminated was placed over these and filed to curved section. Then further side-pieces of 15 thousandth sheet, long enough to encompass the cockpit area, were added. They are anchored temporarily at the rear by a bit of scrap sheet.



The bottom of this area has a curved section, and will in some degree be visible through the open cockpit area. It was, I am reasonably sure, on the actual aeroplane, armor plate. It is made from a piece of 2mm sheet, with billets of 1mm sheet added at the sides and rear. The inside face is scraped and sanded out, and the other face is filed to its proper curves and contours. Once this has been done to near finished standard, it is glued to the rest of the forward element, and sanded in.






The rear portion of the fuselage is a pretty simple box, with the base from 1mm sheet, and the sides from the same 15 thou sheet as the cockpit area sides of the forward elements. These were all cut over-size, with the sides affixed to the bottom, and then trimmed and sanded to proper size and shape.






The last picture shows both fuselage segments loosely taped together for reference.

I am not decided yet whether I will put on the rear fuselage turtledeck before or after the two fuselage elements are joined.