Focke Wulf Fw 44 "Stieglitz"
with Seidel ST 770 radial engine
Like many before, I got hooked on E-bay, too. After I had won an auction for an old Seidel ST 770 seven-cylinder radial engine I was looking for a suitable model and found this beautifully built-from-scratch Fw 44 "Stieglitz", equipped with a Zeonah ZG 62 gasser and a very untypical cowling. The perfect conversion project!
Fw 44 built from a Bob Morse plan.
89 inch wing span an ca. 27lbs
Firstly it needed a new engine bulkhead. I built this from 6 mm birch plywood, which I reinforced with three layers of 160g/square meter glass fibre on the engine side, and one layer on the other. The throttle servo was placed directly on the backside of this bulkhead, and the golden resistor of the on-board glow-heater  (by Mircrosens) on the front side. I was able to use the old mounting holes (plus one hole) of the ZGs hydromount.
This way the whole engine unit including bulkhead can be detached very quickly.
as usual:
clicks on the pictures enlarge them. All of the pictures!
At first I flew the airplane with the old NACA Cowling. Even though purists might raise an eyebrow, rest assured that this version actually existed. It was a prototype to test a new BRAMO engine.
The new Cowling
Firstly I built a new firewall. It is positioned direcly behind the engine between crank case and engine mount. The side panels come to rest on the small rim of that fire wall. This way most oil spray can be kept from the inside of the model. After all, running the Seidel is known for being somewhat of a messy affair.

For the original positive mold of the firewall I cut a bulkhead from 3mm ply and reinforced it in the back with balsa. This way the finished firewall would have a lip bending backwards, on which the side panels come to rest.
Now I adjusted the bulkhead's shape. After giving it an initial angle trim on the disk sander, I bolted it to the engine mount. Next I took a stripe of aluminium litho plate, stuck a piece of tape to its backside for protection and used it as a guide for the sanding tools, thus avoiding to scratch the fuselage. This way I was able to give the bulkhead's rim the correct angle at every position. 
After applying putty, sanding, priming and sanding again I screwed bolts with an inner M5 thread into the back of the form. Now I was able to bolt the form to a solid piece of warp-free MDF (fibro wood). I closed the three holes for the engine bolts from behind, leaving them as recessed impressions in the front. Later, in the negative mold, they would stand up, marking the positions for washers that would be molded into the laminate. Finally the bulkhead was spray-painted with two-composite car paint.
Now the usual procedure followed: First a layer of separator wax which was applied using a dusting cloth. I paid special attention to the gap where the bulkhead meets the base plate, making sure that it was sealed. Next I sprayed a thin layer of PVA, a liquid clingwrap so to speack. This separator is water soluble, making it easy to clean the tools and - more important - to separate the mold under running water.
A Negative from the Positive
Finally it was time for the first layer of epoxy. I used white gelcoat which I apply in a thin layer. The advantage: all mistakes and scratches can be seen much better later, than when using a clear gelcoat. The gelcoat has to cure for about four hours, depending on room temperature, until it "gels". It really is a matter of feeling and experience: Too long and the next layer won't stick well. Too short and you will push the first layer of glassfibre through the gelcoat. Trial and error...
After the gelcoat had cured enough I filled up the sharp edges with a special mixture: Epoxy with tixotrop powder, cotton dust and 5mm fibres. The tixotrop powder stops the resin from running, the cotton makes it thick like putty, and the glass fibres serve as filler and stabilizer. This treatment is important because it is impossible to laminate around sharp edges.
Three layers of 163g/sqm glass fibre followed and one last layer of heavy 390g/sqm fibre all applied with two component epoxy resin.
By the way: all glass fibre and epoxy materials and tools are availabel online from R&G
A Positive from the Negative.
After curing (12 to 24 hours depending on room temperature) I was able to separate the negative mold from the positive. The PVA separator dissolves under running water and releases the mold (hopefully...) Now the edges were trimmed and sanded to a workable finish.
Finally I it was time to laminate the firewall. I have taken a habit of coloring my laminates. This way I can see where I have applied resin yet...R&G deliveres the proper colour paste which can be added up to 10 per cent. If you work really carefully and exactly you can create a surface that does not have to be painted. Well, if....
Since the firewall comes to sit right between the crank case and the engine mount, I added Seidel's original tapered aluminium washers into the laminate. I just had to position them over the protruding drill holes in the negative mold. Very convenient! After gelcoat and filling of sharp corners I added five layers of 163g/sqm. I cut holes into the fibre mats where the washers are, except for the last layer.
After curing, taking it from the mold and cutting and sanding the edges I had a perfect firewall that fit snuggly into place on the engine mount. Neat, isn't it?
Next job was to build the Stieglitz's typical engine cowling.  At first I pondered the possibility of making it from aluminium sheet, but I quickly refrained from that idea. I do not have the tools, let alone the skills, for such a task of perfect metal bashing. So I decided to make it from glass fibre as well.
For this I had to take exact measurements of the engine. I had to find the perfect curve, that makes the transition from the side panels smooth as well as leaving the prop base free and fitting under the collector ring. Sounds complicated, but with the help of a good drawing program it is a piece of cake. I transferred the top of that curve onto a piece of hardwood, cut it out and glued a strip of sanding paper to it. Lacking a lathe this helped me with "turning" the tip of the dome.
"The Dome"
To complete the cowling mold I used the positive mold of the firewall again. I glued a piece of hardwood to its back and then drilled an 8mm hole right in the centerline of the crank shaft, tilting it by 1,5 degrees to the right to provide for the side thrust of the engine. As common with biplanes downthrust was ommitted. A birch dowel led the way to the tip. I filled up the gap between tip dome and firewall with balsa and glued everything together under pressure. The higher the pressure and the smaller the amount of glue, the more easy it becomes later to shape the mold.
Now an extensive shaping and sanding job followed. Quite a piece of work! And don't forget to check the surface and the curve frequently against light. Finally, when you hold such a smooth piece of wood in your hands, a feeling of pride emerges, only to be crushed again after applying the first coat of filler. Oh, my god! So, more sanding, filling, sanding followed until the form was good enough to be spray painted using two component car paint. Looks great, doesn't it?
(By the way: Don't forget, all pictures can be enlarged by clicking on them. Some will change when running the mouse over them. Neat effect...)
I bolted the finished positive mold to the same base again, as with the firewall, using the same bolts that were still in place. Next I made the negative mold and then the cowling itself in the same way described above.  Doing this it was important to cut the fibre mats into pieces, so they could be laminated into the deep, pot-like mold. You will notice that the fibre mats can be shaped and drawn around spheres quite well, but there is a limit to this. I used four layers of 163g/sqm, cutting each layer into two pieces that overlap. Worked great.
The cowling turned out well. But now I was facing two problems: Firstly, where exactly was I to cut the cowlings base? Secondly: Where to cut the cutouts for the cylinders?  One wrong cut and I would have to had made a new cowling.
I tackled the first problem by building a wooden construction as shown in the pictures. I bolted this construction, as well as the engine with firewall installed to the workbench. I made a white PVC tube that fits snuggly over the prop-base and the front of the crank case as well as into the cutout in the cowling. Now I could remove the engine and place the cowling in its place. (place the mouse over the picture with the engine to see the effect)
A felt pen taped to a piece of wood helped marking the line where to cut the cowling on the inside.
Now I was able to precisely cut the cowling using a small drill and diamond cutting disk.
For the cylinder cut-outs I made templates from PVC. Since the engine is mounted with a side thrust and since the firewall is not perfectly round, but rather egg-shaped, all seven templates were different from one another. A litte sanding and adjusting and the engine fit perfectly.  (place your mouse over the picture again. )
I used 5-min-epoxy to glue 14 small hardwood blocks onto the firewall right where the "dome" would be fixed, using scale lens-head screws. Before glueing them into place I drilled 2mm holes into the firewall and sawed a 2mm deep cut at an angle into the undersides of the blocks. Now the epoxy could creep into theses slits and into the holes, making a strong bond, that will not come lose even under vibration.

The long holes in the tip of the dome were marked using PVC templates as well. After priming the cowling I indicated fake rivets, using white wood glue that I applied with a syringe and blunt needle the sort that dentists use. Finally I spray painted the cowling and firewall in the color of the airplane. The 5mm holes that you see in the firewall will be used to thread the glow plug leads through, protecting them from vibration and sealing the holes using small pieces of silicone fuel line.
The Side Panels
klick hier für Bilder des Originals
A problem seemed to be the air outlets on the rear of the side panels. One would have to make steal tools to bash them without creasing the material. I took the liberty to make them seperately and then position them into cutouts. The original had a row of rivets on the back side of those air outlets, probably to hold a reeinforcement. I deviated from scale here positioning this rivet line to the front of the outlets to hold them in place. In order to be able to press the outlets into shape I made wooden templates and used a vice afer carefully heating the material. Small creases could be hammered out or would disappear behind the panel anyhow.
All cutouts I made using a wood drill first and then a file. The advantage of the wood drill is that its tip shape cuts perferct circles into the aluminium without bending it. A CNC-mill would be more elegant, but I don't happen to have one handy!
Since I could not find any piano hinges small enough in Germany I ordered them from Jerry Nelson in the US. Jerry delivered promptly.  I removed the inner rods and made new ones from 1mm steel wire bending the ends at 90 degrees. This way I can remove the panels easily. The hinges were riveted into place, using 1,4mm copper rivets.

Rivets and small scale screws can be found with the model train scene. I ordered my material, copper rivets, rivet tools and screws from Fohrmann in Germany. Fohrmann also delivered quickly and in an uncomplicated way.

I made the latches myself as well. I used a slightly bigger piano hinge, that I took apart, as lead.  Then I bent a 1mm steel wire in a particular way as shown. (move your mouse over the picture to see the backside of the panel)  Now the part of the wire that is bent 90 degrees moves over the brass tube of the piano hinge thus clicking in place and fixing the latch in the closed postion. A solution that does not only look absolutely scale, but also works great.  Oh genius, when you strike me....
On the original Stieglitz the front bulkhead is situated directly under the aft rim of the side panels. However since the model was constructed differently a conversion attempt would have meant to cut away a good piece of the fuselage's front and rebuilding it. Too much effort for little effect I found. Please forgive this slight inaccuracy.
I just cut out openings for the fixtures and hinges leaving the rest as is. I did not want to cut out the places where the air outlets will sit, because the model's side panels are part of the stress absorbing structure. I just painted them black instead. The carburettor will get engough air through the old reso-tube tunnel of the ZG 62 that is still in the model.  I can live with that solution, can you?
The brownish tape on the firewall is (sinfully expensive) teflon tape. It is used in the man carrying aviation for exactly the same purpose and it is acid and heat resistant. Now the side panels come to rest on the firewall without rattling or scratching. A very elegant solution, might I say.

Today (Halloween 2004) I flew the Stieglitz for the first time in its new dress. I had put the c of g forward a bit by replacing one of the batteries with a lighter one. (Batteries are in the back) What a difference! It flies very docile now, the easiest to fly model I have. One just has to get used to the extremely slow landings and - off course - it needs rudder in turns.

I left the collector ring off. You cannot immagine the sound of the radial, when it the Stieglitz taxies out at just above idle. You have to look twice to see, its not the original. And those slow, low flybys with quarter throttle, when the prop turn around 2300 rpm. That is scale! I was thrilled.

I hope this description has given you some ideas for your own projects. In any case I'd love some feedback. Would you write me an  E-Mail?
However the Stieglitz is more commonly known - and more beautiful as I find - in the version with the cylinders of the  Siemens/Halske-engine exposed. So I converted the model. You see the finished project on the left and a detailed report follows:
Here you see Fw 44N, D-EHVA, with NACA-Cowling installed.
I made the side panels from 0.3 mm aluminium sheets. Printers use those and they call them "litho plates". A friendly local printer will be glad to give you some used sheets for free. The material has great properties. While being stiff enough (don't use thinner material) it can still be cut with a good pair of scissors or a very sharp knive. Sanding and shaping is easy and it can also be bashed into shapes.
Click on me to enlarge me to 1024 x 768 (wallpaper size)