AEG N.I (C.IVn) C.9378/16, Late 1917-Early 1918

by George Grasse


THE COMPLETED MODEL:  AEG N.I C.9378/16 is completed, flying off at dusk for a night bombing mission across Allied lines.   The complete story on how this major modified model aircraft was built is shown in the following panels in order of construction.  All of the background data, history, and technical numbers appear in my Historical Journal Issue 12.  For now, you can follow the steps I had to go through to get this thing built and finished.
17 April 2011
When first developed, the AEG N.I was known as the AEG C.IVn being a three-bay version of the two-bay AEG C.IV.  Main recognition features are shown in this photo: 1) three-bay wings; 2) support truss over the center-line of the top wing; 3) the Benz Bz.III 150 hp engine; 4) the high exhaust stack to dissipate exhaust flare and protect the pilot's night vision; 5) the removal of the pilot's forward firing Spandau machine gun (not visible in this photo); and bomb racks on the underside of each lower wing (not really visible in this photo).  Not many photos exist of the AEG N.I (C.IVn) but one unique feature was the hand-painted four-color night hexagonal camouflage scheme.  The photo above shows the early and typical AEG two-color dark green and lilac random scheme.  Photo credit: Over the Front, Journal of the League of World War I Aviation Historians, Volume 23, Number 4, Winter 2008, page 362. (via J. Herris)
The AEG N.I (C.IVn) is not unlike all of the other German two-seat army cooperation aircraft of World War I but it is an unusual aircraft in the details of its appearance, its function, and relative scarcity.  Yet the AEG N.I (C.IVn) filled the role of a short-range night bomber as a specialized single aircraft assigned to frontline aviation units in direct support of the infantry.   German Feldflieger and Artillery Feldflieger units in direct support roles were increased in their establishment from six aircraft to nine aircraft in late 1917.  It came about in this way.

Germany anticipated the entrance of the United States in the Great War and by mid-1917, had launched the "Amerika Program" designed to increase its war potential before American forces and production would have a strategic influence on the outcome of the war by mid-1918.  When American ground forces were deployed in mid-1918, the German front line would have to be expanded with more infantry divisions.  The Luftstreitkrfte  (German Air Force) implemented a plan to increase the number and types of air units including Artillerie Flieger-Abteilung or FA(A) units to support the additional frontline infantry divisions.  In general, one FA(A) unit of six aircraft was assigned to each frontline infantry division to perform the necessary local duties of artillery spotting, reconnaissance, photography, and limited ground support.   FA(A) units were typically "protected" by escorting two-seaters from nearby Schutzstaffeln or Schustas who would fly with or nearby the, say, artillery spotting unit to ward off any attacking enemy aircraft.

Often, Schusta aircraft would operate in twos or more and perform ground attack missions.  This proved so successful that the Luftstreitkrfte removed these units from their "protection" role and made them strictly strategic ground attack formations which had a significant impact on ground combat.  However, frontline FA(A) units were now left without "protection".  In anticipation of this problem, the Verst�rkt Program was created in which certain frontline FA(A) units had their aircraft strength increased from six to nine aircraft.  At least one "protection" aircraft, usually a two-seater type associated with this kind of work was assigned.  In most cases, the aircraft was of the CL-Type; it was lighter, faster,  and more maneuverable.

Already, by late 1917, FA(A) units were involved in closer battlefield coordination with their assigned frontline infantry division to the extent that night bombing was adopted as a regular mission.  The concept German multi-engine bombers in the strategic night bombing role was expanded to the use of purpose-built single-engine two-seater aircraft for local tactical use.  Idflieg developed the N-Type classification for which the AEG N.I and the Sablatnig N.I were designed, built, and issued to Verst�rkt FA(A) units.

So, my objective is to take a Copper State kit of the AEG C.IV and convert it into an AEG N.I finished in the hand-painted four-color night hexagonal camouflage scheme of a 1918 FA(A) night bomber.

This photo used with permission from Jack Herris clearly shows the hexagonal "night bomber" scheme originally developed by AEG for their versatile twin-engine "G bombers".  Unfortunately, crew, unit, and date are not known.  Once again, the key features of the AEG N.I (C.IVn) can be seen: 1) three-bay wings; 2) support truss over the center-line of the top wing; 3) the Benz Bz.III 150 hp engine; 4) the high exhaust stack; 5) the absence of the pilot's forward firing Spandau machine gun (normally on the right side of the engine; and 6) external bomb racks on the underside of each lower wing (not really visible in this photo).  Three additional features are seen in this photo: 7) the hexagonal camouflage pattern, 8) landing lights at the forward edge of the top wing above the center pair of struts (better seen on the right), and 9) the raised circular gunner's turret, a feature not seen on the standard AEG C.IV.  I should point out that I use the designation AEG N.I (C.IVn) when the early aircraft were known as AEG C.IVn but the later production aircraft were known as the AEG N.I.  Photo credit: Jack Herris via Email consultation.
6 April 2011

INSTRUMENT PANEL: Before and after images of the instrument panel.  The basic Copper State instrument panel was augmented by a number of gauges, beveled instrument faces, and bits of PE material.  The after-market accessories used were Aeroclub ACV242 Beveled Instrument Faces (PE Sheet), Copper State CS0122 German Gauge Set (PE and Film), Eduard EU9194 WW1 Instruments (colored PE sheet), and various bits and decals from the spare parts bin.  The notch at the top right of the panel is for the butt-end of the pilot's Spandau machine gun which was removed on the AEG N.I since it was virtually useless at night and it saved weight.

7 April 2011
BENZ Bz.III 150 hp ENGINE: Next to the three-bay wing wing set, the Benz Bz.III 150 hp engine was another distinguishing feature of the AEG N.I because the exhaust stack is on the left side (normally right side) and the right side is covered in valve push rods.  I searched all after-market WW1 1:48 scale accessory manufacturers looking for a Bz.III.  There were a fair amount of engines and even a Bz.IV but not the one I needed.  Next, I made a short list of German aircraft known to have used the Bz.III for which there were 1:48 scale kits.  The list included the Albatros D.I, Hansa-Brandenburg W.12, Hansa-Brandenburg W.29, Friedrichshafen 33e, LFG Roland D.VIb, and Rumpler C.I/C.Ia (some).  I have the Blue Max LFG Roland D.VIb and the Techmod Friedrichshafen 33e but I cringed at the thought of cannibalizing the Bz.III engines because replacement would be difficult if not impossible.

That left the option of modifying the Copper State Mercedes D.III 160 hp engine that came with the AEG C.IV kit.  I ignored the shape of the crankcase because it would be hidden deep in the nose of the model.  I had to address three problems: 1) the valve spring and pushrod configuration on the right hand side; 2) the left-hand exhaust stack; and 3) placement of the intake manifolds at the top of each cylinder on the left side,  squeezing them between the exhaust manifolds.  All during this process, I used the excellent photos of a Bz.III found in Wingnut Wings' 1:32 scale kit of the Hansa-Brandenburg W.29.

Problem 1 (Right-side valve springs and push rods): A few years ago, I did an engine conversion for a Rumpler C.Ia from a Mercedes D.III (six in-line cylinders) to an Argus As.III (three pairs of in-line cylinders).  I learned the trick of winding fine copper wire around an appropriate diameter wire rod and then cutting each valve spring from the longer coiled wire (see photo 2a above).  In that photo is shown the copper wire on its wire rod, another finished length, and three separately cut valve springs.  In the upper right hand corner of the photo is shown the engine with two valve springs and one pushrod in place. 

Problem 2 (Left-side Intake Manifold):  This problem was easier to solve than at first.  I drilled out the exhaust ports so I could tack the exhaust stack in place.  Next, I drilled out the intake ports and that gave me a visual representation of how the intake pipes would fit.  There were two choices for piping: 1) solder and 2) small-diameter shielded electronic wire because both are flexible which is critical in the tight space of the engine's left side.

Problem 3 (Left-side Exhaust): Fortunately, I found a soft metal right-hand exhaust stack in my little bag of exhaust pipes.  Metal is important because it can be bent carefully in the opposite direction to make a left-hand exhaust stack.  Using a pair of narrow-nosed pliers, I bent the pipes downward and did a little reshaping and lengthening.  Then I continued the bending to the opposite side and that solved the first problem.



Problem 1 (Right-side spring and push rods): A few years ago, I did an engine conversion for a Rumpler C.Ia from a Mercedes D.III (six in-line cylinders) to an Argus As.III (three pairs of in-line cylinders).  I learned the trick of winding fine copper wire around an appropriate diameter wire rod and then cutting each valve spring from the longer coiled wire as shown in the upper photo left.  Details of the photo  show the copper wire on its wire rod, a finished length of coiled wire, and three separately cut valve springs.  In the upper right hand corner of the photo is shown the engine with two valve springs and one pushrod in place. 

The middle photo left shows the installation of all 12 valve springs.  Note the long tube-like structure near the bottom of the cylinders.  I was going to cut this off but instead decided to drill out twelve size 76 holes that would take .012 piano wire that would simulate the push rods.

The bottom photo left shows the completed valve spring and push rod arrangement.  One step not shown is that the top of each spring and push rod will be filled with a droplet of putty and then sanded down to level the top of the engine.


Problem 2 (Left-side Intake Manifold):  This problem was easier to solve than I first thought.  I drilled out the top of each cylinder to a large diameter.  I thought about individual exhaust and intake ports but the placement of the D.III exhaust which are centered on the cylinder casing meant that two additional holes for each cylinder would not work.  I ended up drilling one large hole.  There were two choices for piping: 1) solder and 2) small-diameter shielded electronic wire because both are flexible and easy to work.  I chose .030 solder wire and completed the modification as shown in the photo at left.


Problem 3 (Left-side Exhaust): Fortunately, I found a soft metal right-hand exhaust stack in my little bag of spare exhaust pipes.  Metal is important because it can be bent carefully in the opposite direction to make a left-hand exhaust stack.  Using a pair of narrow-nosed pliers, I bent the pipes downward and did a little reshaping, trimming, and sanding.  After quite a numbers of tries, I managed to get the exhaust stack to fit.  Based on photos of the Bz.III, I added a couple of plastic intake carburetor "boxes" and a little extra piping.  See the completed engine in Photo 4 below.

8 April 2011
FUSELAGE INTERIOR: This photo shows about half of the interior of the fuselage completed.  The instrument panel and the Bz.III engine have been described above.  The floorboard has to be built up and inserted into the glued fuselage through the bottom opening.  This is not a worrisome task except that every item you add to each fuselage half and the floorboard has to be pre-fitted so as not to interfere during final fuselage assembly. 
1 May 2011
FUSELAGE GLUED:  In preparation for bonding the fuselage halves, the engine and cockpit interior had to be finished out.  The engine needed to have the exhaust stack lengthened which was simply done by cutting off a piece of round plastic rod, drill out holes, insert a brass rod, then glue the extension to the exhaust stack.   The plastic rod has the same diameter as the widest part of the exhaust stack so, when dry, I added putty and, later, sanded down the plastic rod to blend into the exhaust.   That completed, I glued the two fuselage halves together making sure the engine was aligned.  When dry, I added putty to all the seams then sanded them down.  At this point, the reader should know that this is as far as construction goes because it is time to address the 4-color hexagonal night camouflage scheme.   Note the completed engine with its extended exhaust stack.
2 May 2011
This model of the AEG N.I will be finished in a 4-color hexagonal night camouflage scheme hand-painted at the factory.  It was obvious from the start that there are no existing 1:48 scale AEG-type hex decals and that these would have to be hand-painted.  I had to figure a way to "regularize" the hexes.  I came up with the idea of scanning in a hex pattern from one of my old wargaming hex sheets, scaling it down to 1:48 scale, and printing it on my laser jet using clear decal paper.  After trial and error I came up with a small sheet.  The next step was to use a piece of scrap wing painted in an approximate light green as the overall base and sealed with satin polyurethane.
The next step was to apply the decal to the painted surface.  If successful, I would have a hexagonal pattern over which I can paint the remaining three colors of the 4-color scheme.  The basis for the size of the hexes and the colors is Bob Pearson's color profile of the AEG N.I that appeared on the inside back cover of Over the Front, Volume 23, Issue 4, that supported a "Rare Birds" article on the AEG N.I (C.IVn) by Peter M. Grosz, edited and completed by Jack Herris.  The photo at left shows the decal in place and ready to paint.  Note that this is a test piece and I was not concerned with hex orientation at this point.  Now, to painting the decal.
Before I could start painting, I had to come up with a final version of the four colors used in the night camouflage scheme.   I will describe the colors in detail in the next photo section below but for now I can say that it took a while to mix and match (or at least come close to) Bob Pearson's color profile.  It took some time to apply the three colors.   Remember, the overall color of light green was applied as a base and these hexes did not need hex-by-hex hand painting.  After the colors were applied, I oversprayed with satin polyurethane.
1 May 2011
Light Green is the lightest of the four hex colors and it is also used as the overall base color on all components: fuselage, wings, tail, and wheel covers.  All of these components have to be cleaned, painted in light green, and oversprayed in satin polyurethane.  When dry, the hex decal is applied and it receives an overspray of satin polyurethane.  Then, each component is painted to complete the 4-color scheme.  None of the components can be glued to the aircraft as that would make the process extremely difficult.  Later, when all of these have had their 4-color hex scheme applied, construction can resume.  Below is a simple chart that shows a paint chip from the colors I mixed (left column) and their formula (right column).  I do not have a Methuen color guide as these rare and expensive volumes are beyond reach.  Incidentally, I am a little leery of such a system because the person making the analysis is judging by their "eyeball".  Besides, actual extant examples have faded beyond an accurate description.   I pre-mixed all of the colors in sufficient volume so as not to run out and have to mix a batch on my palette which could lead to color variations.  They are all stored in the Andrea/Vallejo style of 17 mil container.  
    Light Green Formula:

1/2 Vallejo VC0974 Green Sky

1/2 Vallejo VC0885 Pastel Green

    Magenta Formula:

2/3 Vallejo VC0812 Violet Red

1/3 Vallejo VC0884 Stone Grey

    Blue Formula:

2/3 Vallejo VC0839 Ultramarine

1/3 Vallejo VC0807 Oxford Blue

    Black Formula:

Vallejo VC0995 German Black


5 May 2011
These photos show the few steps needed to build up the observer/gunner's machine gun circular turret from the square with rounded corners configuration of the AEG C.IV to the circular configuration of the AEG N.I as shown in these two 1:48 scale general arrangement drawing extracts (with credits noted).

Credit: Ian R. Stair in Windsock Datafile 67, AEG C.IV, Albatros Productions, 1998


Credit: Martin Digmayer in Rare Birds AEG N.I (C.IVn) in Over the Front, Volume 23, Issue 4., 2008
I used Aeroclub's ACV101 German Gun Ring accessory kit.  I had to take just a bit of resin off the back of the cockpit to fit the gun ring and keep it level.  A drop of super glue at the front and one at the rear held it in place.  Next, a used a narrow strip of thin copper sheet to form the sidewalls.  This took about five applications of super glue, one at a time until dry to get the piece secured. 
I added my first coat of putty as shown in the photo above.  When thoroughly dry the next day, it was sanded down and a second coat of putty was applied as shown in the photo at left.  When using putty, multiple thin layers are preferred otherwise the chemicals in too much putty can dissolve the delicate surface, not so much with resin but it can soften plastic so keep the layers thin.
This is the final layer of putty that has been sanded down and fits the configuration I was after.  Next step is to apply a primer and "eyeball" for deformities and be sure the built-up area is feathered into the fuselage by sanding with fine grit paper.  The last step is to apply another coat of primer and "eyeball" the finish.
10 May 2011
FINAL FUSELAGE PREPARATION:  The observer's cockpit needed a little filling on the right side.  Incidentally, the odd objects sticking up through the cockpit are the observer's seat belts.  At the right front of the pilot's cockpit is a piece of copper sheet with putty applied and sanded to cover the space intended for the fixed forward-firing Spandau machine gun not fitted on the AEG N.I.  Panel lines have to be re-defined before priming.  Fuselage photo-etched (PE) parts have been added as shown: large and small engine access panels, engine louvres, and the manufacturer's plate.   The fuselage will be primed again and painted overall in light green to start the camouflage process.
24 May 2011
BASE COLOR PREPARATION:  One of the four colors of the hexagonal night camouflage is light green so, as a base coat, it doesn't have to be painted onto the decal hex pattern that will be applied later.  All components including the wings (not shown) have to be painted in light green, have the hexagonal pattern decal applied, and then hand-painted.  Imagine trying to apply that decal over and around some of the components if they were already glued in place.
1 June 2011
METHOD OF MODIFYING THE WINGS:  The top image is the lower left wing straight out of the box for the AEG C.IV.  The middle image is the lower left wing which has had its right section cut off with a new section in the middle.  The bottom image shows the completed lower right wing pinned and glued but not yet puttied and sanded.   The middle section was cut from a spare wing set ordered from the manufacturer, Copper State Models.
1 June 2011
MODIFIED WING SET:  Top and bottom wings have been extended but still need to be filled with putty, sanded, and primed.  Fuselage, ailerons, and horizontal tailplane shown for comparison. 
2 June 2011
LANDING GEAR:  The landing gear struts were made from Griffon Model Hollow Brass Pipe 1.2mm OD into which a length of piano wire .30mm was inserted and the whole "pounded" out on an anvil to get the oval cross-section of the struts.   The piano wire prevents the crushing of the tube and serves as locating pins when attaching the landing gear "V" legs to the fuselage.
8 June 2011
HEXAGONAL DECALS PREPARED: The photo on the left shows the painted components at the top followed by a photocopy cut-out of the same part in the middle, and, at the bottom, the cut hexagonal decals.  The photo on the right shows the decals (left), the photocopy "template" (middle), and the pre-painted components. 
10 June 2011
HEXAGONAL DECALS APPLIED: This Photo shows the left upper wing (top) and the left lower wing with the clear hexagon decal applied.  As of this date, the model has been covered and is ready for some minor assembly and painting of the hexagonal camouflage.
8 June 2011
27 June 2011
TAIL UNIT: The vertical fin was glued first and the rudder attached to it and the fuselage.   The tail plane, left and right, were glued next. FUSELAGE CAMOUFLAGE: The serious painting has started.  Of the four colors in the scheme, only light green was not painted except for touchup.  This was tedious.
27 June 2011
FUSELAGE CAMOUFLAGE: The serious painting has started.  Of the four colors in the scheme, only light green was not painted except for touchup.  This was tedious.
8 July 2011
Wing cabane struts were made from brass tube with a brass rod insert cut to size then pounded lightly with a small hammer to get the oval profile.  The brass rod in each strut is slightly longer to allow for a firm connection to the fuselage and to prevent the brass tube from being crushed during hammering.  In the second photo in the Prologue section below, all struts appear to be light colored so I used the light green of the 4-color hexagon camouflage.  The main wing sections have already been prepared and are in process of being painted.  In the meantime, I have to work in the cockpit area before wings are glued in place.   I have a lot of room to do this now before it gets complicated with strut wires.  I'll be working on the windscreen, radiator pipes, the observer's underwing bomb release mechanism, cabane strut wires,  and the gravity tank fuel line.  I have printed decals for the rudder EK, fuselage EK, and fin serial number which will be applied after the above cockpit area is finished.  At that time I will overspray the model with satin polyurethane to protect the paint and provide a slick surface for the decals.
22 July 2011
Progress has been slow because each hex excepting the light green base color has to be painted by hand.  I believe now that I should have invested the time to colorize by clear hex decal master.  This photo shows the upper side of the bottom wings and the underside of the top wings.  I still have to paint their opposite sides!

I have to also work out the upper wing center section truss structure which is not difficult at all.  I also need to work out the bomb release mechanism that is seen on the outside of the observer's cockpit in the second photograph of the Prologue section of this article.  It appears to be a mechanical device that when raised releases the bombs which are carried three under each wing.  My guess is that the bombs had to be released simultaneously otherwise the aircraft would be thrown about from the sudden loss of weight on just one side.  It's possible that this lever was "notched" so one pair could be released, one from each side.

31 August 2011
The bottom wings are glued in place but the top wing outer panels are not.  The upper left wing panel had a break while cutting out the slots for the night landing lights.  I used super glue and a 400 grit piece of sandpaper at the stage you can see.  I'll smooth a bit more with 600 grit and it should be fine - painting will take care of that.  Notice that the wing struts are not in place.  I couldn't resist seeing what this two-seat monster looked like with the wings in place.  Here's what has been done which you can't see in this photo: 1) all of the wing rigging holes have been drilled out; 2) turnbuckles have been added to the fuselage near the cockpits for more rigging; 3) the night landing lights have been installed.


7 September 2011
RIGGING HAS STARTED:  All rigging holes have been pre-drilled.  Those on the bottom wing will along the rigging thread to pass through, attach to a weight, have glue applied, and wait until it dries, then cut off the excess.  There will be some sanding and repainting to cover the disturbed area.  The underside of the top wing will have corresponding holes drilled for the rigging wire but these are glued into the holes and no other work needs to be done except pass through their corresponding holes on the bottom wing. 

I have to have a total of six pairs of struts for this 3-Bay wing.  Copper tubing 1.0mm OD was used and cut to length.  Solid brass rod with a .81mm OD was inserted in each one with at least a 1/4 inch protruding from each end.  The struts with rod insert were each "pounded" down likely to achieve a oval cross section.  One pair of struts was put in place, checked for fit, and glued.  Then I jumped over to the other side and did the same one that pair of struts.

There is some sag expected and I intended to use the bonding of the struts and the tightening of the rigging to pull the wings into alignment.  Turnbuckles were used on rigging attached to the fuselage 



21 September 2011
SCRATCH-BUILT UNDERWING BOMB RACK" RIGGING HAS STARTED:  The AEG N.I was designed to carrying three 50 kg bombs under each wing.  I studied photos and reports on Gotha bombers and it was discovered that a simple metal framework rack with appropriate retaining hardware was used so I copied that design in a simple way. 

The lower left quadrant shows three Copper States 50 kg bombs assembled and painted in Misterkit MKGC08 German Light Grey.  The next quadrant shows the completed bomb rack structure made from .040 x .040 plastic stock.  The upper quadrant shows how the bombs are placed into the racks.  Later, a thin lead sheet strap will retain the bombs.

22 September 2011
MAJOR SUB-ASSEMBLIES ARE APPLIED:  This view shows the placement of the two underwing 50 kg bomb racks.  The exhaust stack for the 150 hp Benz engine is not in place.    The AEG N.I was designed to carrying three 50 kg bombs under each wing. 

Radiator pipes (inlet and outlet) are in place and painted a dull copper/gun metal grey mixture using Vallejo paints Copper and Gun Metal Gray.

22 September 2011
RADIATOR PIPES:  This view shows the placement of the two inlet and outlet radiator pipes.  The straight pipe which flows over the top of the engine is made from brass rod but the inlet pipe which disappears behind and down into the rear of the engine was made from .030 solder wire because I had quite a few turns to make.   The AEG N.I was designed not have a forward firing Spandau machine gun and none were added.

The nearly scratch-built Parabellum machine gun was constructed from a hodge-podge of left-over machine gun spare parts

22 September 2011
IN-FLIGHT VIEW:  This view dramatizes the extra long wing configuration which provided extra lifting power for the total 300 kg bomb load in addition to the crew, crew weapons, ammunition, water, oil, and fuel.
22 September 2011
RIGHT REAR VIEW:  Each wing bay adds two struts and six wires.  Not including battle damage, the ground crew had to run the aircraft through its rigging procedures to "true-up" the wings. 
22 September 2011
LEFT REAR VIEW:  The observer sat in the rear sear and was the commander of the aircraft.  Before a bombing run, he would tap the pilot's head and shout, "Cut the engine"., and the aircraft would be glided towards the target to avoid detection.  Note the subdued Eisernes Kreuzen. . . . very simply left plain black with no white surround, another detection avoidance technique.  Also the exhaust stacks were made a little longer and were often fitted with flame arrestors that would minimize the glow of the sputtering engine.  Cockpit lighting was produced from low voltage "blackout" bulbs.

--------------------------------------------- FINIS -------------------------------------------

This 1:48 scale model is based on photographs and color profiles featured in Over the Front, Volume 23, Issue 4, see bibliography below. 



Grosz, P. M. AEG C.IV, Windsock Datafile 67.  Berkhamsted, UK: Albatros Productions, 1998.

Grosz, P. M.  Rare Birds - AEG N.I (C.IVn), Over the Front, Volume 23, Issue 4, Winter 2008.  Journal of the League of World War I Aviation Historians.  The article is enhanced with 1:48 scale multi-view drawings by Martin Digmayer and color profile art by R. N. Pearson.

Herris, Jack.  Additional photos and correspondence via Email.







� Copyright by George Grasse