Started an experiment tonite....

[Sabre F-86]

Well, I finally found a picture that pretty much represents the particular Wal I'm building. Heres a link to the photo.....

 

http://www.k2.dion.ne.jp/~bobcat/HTMLmemo/...bu/Wall-2B.html

 

Looking at the specs it seems the Japanese built Wal was pretty much identical to the way the designer set up the Wilhelmshaven kit.

 

In the mean time, some more photos of progress. The first one is of the completed starboard sponson, as far as it goes with the kit templates. You will notice that the end plate is a bit recessed. I'm not sure if its supposed to be that way, but I checked the parts and the sizes are correct as far as that goes, so it looks like the endcap is recessed. I'll have to look in more detail at the various photos but I think its wrong and needs to be filled flush. Naturally, all the cleating needs to be added, along with the two round tank openings.

 

 

 

The next shot is of the trial wing structure I made up to figure out how to build the wing. As no structure is given other that the spar which runs 80% of the span, the wing skin was just basicly folded over the spar and glued at the trailing edge. Very flimsy and also very difficult to do with any consistancy using plastic. Ergo a structure to support the skin is required and we always go with what we know best. Viola!, Your basic stick n wood wing made in plastic. The skin in this case is .015, much more flexible and so it was bent round the dowel and gives a nice airfoil.

 

 

 

Heres the working wing structure part built. This is the bottom skin, made of .030 sheet with the spar and part of the rear ribs installed. Overall its about 27 inches long and 4 inches wide.

 

 

Heres a closer view. The spar in the paper model is about 12mm tall with sides slanting inward to the top. Its 5/8s wide at the base and 1/2 wide at the top. Rather than try to do that, I just made up an upper and lower flange of those dimensions and built a box form with parallel sides to match the height. This is glued in place along the 1/3 chord line. Individual ribs of basic triangle shape are cut, notched to fit the base flange and glued in place on 1 inch centers. The center area has a notch cut out for the pusher prop, so it gets boxed in with .080x.125 strip. Same thing for the ailerons. I allowed an additional 2mm for the round stock that will make up the leading edge of the ailerons, they will fit into the recess in the trailing edges. After all the aft side ribs are in place I'll start making up the forward half ribs, notched to accept the 1/4 dowel that will be the leading edge. The bottom skin will be forced to meet the dowel with a shim and then epoxied in place. The upper skin will be beveled at the trailing edge and then epoxied onto the rear 2/3s of the wing and left to harden. Then the forward 1/3 will be forced down onto the dowel, epoxied and taped in place. Once its all done, the wing tips will be trimmed square and tips will be added to match the final planform. It should be strong as a brick outhouse.

 

 

 

These shots are of the fin and stabilizers, temporarily rigged with the elevators and rudder. If you look closely you will see that the stabs need to be trimmed to match the rudder contour. The Elevators are also needing to be shortened a tad and the taper at the end needs to be changed. Note the mismatch between the stabilizer tips and the Elevator tips. This shot shows how the movable surfaces mesh into the trailing edge of the fixed surfaces. The ailerons will be the same. Details like hinges will be added after I get all the bits down pat and matching for length, thickness and tapers.

 

 

 

 

The last shot is the tail assembley again, different angle.

 

 

Once all the parts are correct and matching from side to side, I'll fill what ever gaps n gouges that need it, and the whole assembly can be mounted to the hull. I'm going to drill holes in the hull for some bamboo skewers, these will serve to position and secure the assembly. Later details like the auxillary elevators can be added later to pre-drilled holes.

 

I had a look at that pre-glued veneer, its pretty useless for this task. Its got paper and gum on it, IPA won't touch it but lacquer thinner will. Then you have to scrape off the gunk, and you are left with a piece of veneer about .005 thick. I'm not sure its worth the agony to use this junk. I'll most likely go to plan B and use coffee sticks.

 

Sabre

[Hubert Boillot]

HI Sabre,

 

you're making swift progress on that one ! Well done !

 

Just found in "Cockpit Profile" #1, a German publication series devoted to German A/C cockpits, which can be purchased from Moduni, the cockpit photos you were looking for. I PMed you the pics...

 

A very worthy reference series for all German A/C enthusiasts !

 

Hubert

[Pfuf]

Fantastic follow this build realy love those flying boats great work so far hope to see more.

 

johan

[Sabre F-86]

Took a bit of a break to work on my boat last week, n hurt my back so I didn't get much done on the Wal over the weekend. Finally sat down tonite to work on the wing again. It appears that my spar is a bit of a mess as far as straightness goes, and the front web is going in every direction except 90 degrees. Oh well, on to plan b for the leading edge.

 

Given the distance from the spar to the leading edge I've decided to just glue the dowel to the lower skin with epoxy and then put on the upper sheet from trailing edge to spar cap. Once thats done I'll put a shim of about 1/8 under the lower skin to raise the dowel and then pull the upper skin down and tape it in place. This should give me a reasonable airfoil.

 

I decided to purchase the only book out there on the Wal, its called Dornier Wal: a light coming over the sea by M. Michiel van der Mey. The fellow has spent some 30 years researching the Wal and its a pretty good read. Its a soft cover book, loaded with photos and some drawings, and goes into fair detail on who built the beast, who flew it and the record setting flights. The authors sentence structure is a bit odd compared to ours, given that its not his native language, but still quite readable. Im about half way thru it so far and loving it. There are also some pretty good photos of the interior and they are really impressive for an aircraft that was being built of solid aluminum long before others got to doing it that way. The Wal developed quite the reputation for strength and durability, and I found it interesting to learn that Spain had theirs in service up until one was destroyed in a crash in 1950 and they decide to sink the remaining ones some where off the Spanish coast. I was even more surprised to learn that the Dutch East Indies navy had some 46 of them and the Soviets had over 60.

 

One thing for certain, it looks like I'm going to have to do something about rivets. Looking at the interior shots, and some of the exterior shots, you can see them quite plainly in some shots. I'll have to give some thought to how to proceed with that before I start gluing all the subassemblies together.

 

I hope to have some photos of the wing in a couple of days.

 

 

Sabre

[Sabre F-86]

Put in some more time tonite, working on the tail assembly and the wing.

 

I've got the tail pretty much symetrical now, one stabilizer was about a millimeter too wide, so I filled the leading edge with CA and some scrap plastic and sanded it down to match. I've got the mating joint of stab to rudder pretty close, and will leave it as is for assembly. Once its all put together and rock solid I can scab in some small bits of sheet to close the remaining gaps. The elevators are now being reworked to take care of the dissimilar taper at the ends and trimmed to fit. Every thing jigs up nicely to 90 degrees. I have to put some strips on first before I glue it all together but I want to finish the book first and have a real good look at the photos.

 

Yesterday nite I glued the dowel to the lower wing skin with mucho CA. I let it cure over night, and this morning I trimmed it down to about 5/32nds, with a slight angle so the upper skin would lay flush when bent into position. Early in the afternoon I glued the upper wing surface on to the wing and spar assembly. I clamped it all down under a piece of 1/2 inch angle iron, and this cured the wavyness of the trailing edge I noticed after gluing in the ribs. I let it harden for a couple hours, and then took the wing and stuck a lot of masking tape strips to the lower panel. I then clamped it, lower skin down, with the leading edge elevated about 1/8 inch, and a steel 1/2x1/2 angle along the spar cap to force the lower skin flat against the table top. This put a curve into the lower leading edge. I applied a bead of CA to the dowel, and forced the upper skin down, taping it in place as I went. Its curing now, and should be solid by morning. I figure I'll need to do some sanding to get the leading edge into decent shape so I'm going to pour some epoxy in behind the dowel and let it sit. This will give me solid support and some extra meat for sanding.

 

I should have some good photos tomorrow once the suns up.

 

Sabre

[Sabre F-86]

Couple of photos of the wing skin gluing. First one is the entire wing, shimmed up at the leading edge and clamped along the spar cap. Lots of masking tape to hold the upper skin down to the dowel.

 

 

 

Second shot is from the end of the wing and you can see that there is no structure at all infront of the spar. You can see the front face of the spar is off plumb. Next time I do one like this I'll take a bit more time to get it all squared up. So the dowel was glued to the lower skin, then it was shimmed up. Looking at the photo it appears that 1/8 was a bit much. The dowel was sanded down to a flattened wedge shape and the upper skin was then glued in place with lots of CA. Its not a bad airfoil, and some work with heavy paper will round it all out to give a nice leading edge.

 

 

 

 

At the moment the entire wing is now wedged leading edge down between the two angleirons, and I've poured a ounce or so of epoxy into the leading edge after damming up the ends with tape. It should be cured in an hour or so, and I'll go have a look and start sanding the joint. After that I will remove the skin over the ailerons and the center section and start to work on the wing tips.

 

Sabre

[Sabre F-86]

Ok, its starting to look like an airplane now, instead of a long skinny boat. Heres the first attempt at mocking up with all the major components.

 

 

Next;

 

 

A side view of the engine pod on top of the wing. You can see the original cut out on the side of the housing. This is what the plans said the wing should look like. The wing as built looks much closer to a proper mid 20s airfoil. I'm not too happy with the way the pod is represented anyway so I'm going to use it as a pattern for a second version, with more curves and details. This is just way too boxy and doesn't really capture the lines of any of the various photos in the book.

 

 

 

 

Rear quarter shot of the engine pod on the wing with the prop cut out.

 

 

 

Low forward shot of the wing on its platform. Sorry about the lack of focus. At the moment there are only the 4 struts made up, once I have everything as squared up as I can get it, I will cut and fit the diagonals installed crosswise and fore n aft to make the platform rock solid. The section of the platform forward of the struts will have to be cut down to remove excess material.

 

The struts were made up using Herberts' method, stiff wire sheathed in thin plastic. Mine are more diamond shaped as they are only about 7 mm in width but with a bit of sanding they will have a nice foil shape to them. The wire core is a must to support the wing and engine pod.

 

There will also be a small ladder coming from the fuselage up to an access hatch in the bottom of the wing. The pod was set up so that the mechanic could climb up, and work on the engines in flight, he even had a seat and hatch to look out the top of the pod. Apparently this was a pretty safe place to be in the event of a serious crash. In most of the accidents noted in the book, the mechanics were most likely to survive, because of their position. All the engine instruments were located in the pod as well, the pilots had primarily flight instruments on their panel.

 

 

 

 

Front view. I was sloppy in setting up for this shot so it looks squewed. The tail fin is also a bit off to the left side at the leading edge, as right now the only alignment pin is at the rudder post. Before I do the final set up and gluing I'll have to jig up all the structures and square them.

 

The cockpit coamings and windscreens are yet to be fabbed up. I should have worked up the cockpit first but being impatient to see what the hull would look like, I didn't and now have to contend with working thru that opening to build the cockpit. Doh!

 

 

I have a request, if anyone out there has a seated pilot or two, of the WWI or golden era period, I'd love to get my hands on it. Right now I'm using the pilot out of the 21st Century Zero but I'd like to get another pilot for the Wal.

 

 

Any comments or feedback appreciated.

 

Sabre

[henry brown]

What a wonderful subject and build, brilliant. I am inspired.

I like the way you have used the card model as a starting point.

 

I came across the following in my day job which you may already know about , but if not they might be a good source of

archival material of your Wal cockpit etc.

 

http://www.dorniermuseum.de/en/startseite.html

 

 

Henry

[Hubert Boillot]

Hi Sabre,

 

she is definitely taking shape ! What a great build ! I am glad (and flattered ) that I could inspire you an idea to do the struts. Some of the ones I did for the Hansa were not perfect shape either (you have to control liquid cement quantity carefully to avoid deformation of the thin card), but I corrected their profile with either white Milliput or CA glue with kicker.

 

Keep on the good work on an original build !

 

Hubert.

[ruzlkampf]

^^^^What Hubert said!! ^^^^ Whoohoo, big moment in a build when you can mock everything up and take a look at it! This is sooo cool. I did the same thing with the pit on the pancake,....good excuse for me to keep any eye-bleeding detail to a minimum. (and I'm lazy) Muhwahahah. Looking good Sabre, REAL good! Later, Russ

[Sabre F-86]

I know what you mean Hubert, most of my struts have finger prints embedded in them from a tad too much glue. I'm using Tenax as well which is very hot stuff so the plastic melts almost immediatley. Once I get everything figured out I'll spend an evening finishing the struts and all the mediocre joints. Having the steel rod in them does make for a strong truss though, so its well worth the extra effort. I remember some WWI stuff I built over the years where the struts deformed in a hot room and the wings sort of pancaked together. No way thats happening here.

 

As for the cockpit, if it looks like I'm going to make a mess, I've decided to put a tarp over the cockpit. Lots of photos I've seen with that, to keep the rain out of the hull. People can speculate as to what the pit looks like. Next one I try will be from a more detailed paper model which comes with a pit, so the basics are there. I'm rather surprised that the Willhelmshaven model didn't have a pit but in hind sight, as my ability to read German is improving, it appears that the opening was never intended to be cut out. The flat base under the turtle deck shows the opening as black and then the coaming comes down to meet it, but I think perhaps I made a booboo by opening it up so the lack of cockpit is my fault realy. I could have just left it unopened but at this scale that would look pretty bad.

 

Oh well, live n learn. I may yet take a razor saw to the upper deck and open it up for a decent pit. Time will tell the tale on that. I just started a work cycle so I don't expect to get much done this week. I bought some birch veneer, and have the strips cut for the props, so I'll try to laminate that so its ready for carving, and continue with the wing and platform assembly, time to build a solid jig for alignment. I'll be starting on the ailerons and the matching openings as well today if I get some time.

 

 

Sabre

[Sabre F-86]

As a side note to the paper to plastic conversion method, I just had a large package arrive from Poland with some new paper models. Some of them are very comples with lots of curves, and a couple of them are very basic with vast expances of flat sheet. Very easy to convert to plastic, and not available in as injected kits and pretty unlikely to be so in our scale. (Some may be available as vacuform)

 

Heres what I picked up. Vickers Vimy, F1M Pete, Ar-196, Po-2, Waco Hadrian troop glider and the BV-138 flying boat. The Vimy and the Hadrian are especially plastic friendly.

 

BTW, I messed up and ordered two of the Hadrian and the BV-138 by mistake, they are for sale if anyone wants to give it a try.

 

 

Sabre

[Sabre F-86]

Haven't had much time to work on the Wal, but the diagonals for the wing platform are partly in place, and work continues on bodging a cockpit together. Good weather and a boat keep calling me.

 

Sabre

[Azgaron]

Very interesting project Sabre! Looking good so far!

 

Cheers,

 

Håkan

[Derek B]

Sabre,

 

I am still very impressed at how well the paper patterns tranfer to plastic - very impressive. It should look a real stunner when completed.

 

Derek