A revisit to a scratch build Folke Wulf 190 D-9 Dora build from 2009

[Neons]

This was built and flown some years ago. It came out beautiful and flew very docile and smooth. The build log was not intense like others I have built. This is a total scratch built model that started out to be a large park flyer of light weight for a hand toss. Of course the build thread changed course when my late Master Builder John Morgan went the scale route with a fiberglass fuselage. I went the same route with an epoxy fuselage and hot wired wings. Oh well, I guess I just kept at it and I ended up with a very close to scale German warplane of real beauty way over the expected top.

There is a short video on the the controls and maiden test flight in YouTube here also:
https://youtu.be/kmaQnyHwXrs

I will add updates as I have time available to add more on the build. Below is the link to go to if there are some impatient readers. It is okay to do that also. First I will start with my picture holding the finished aircraft. Also to let you know I cannot reply to questions in this thread due to membership stop gaps in the creation of this club thread. I can answer RC Groups comments though.
https://www.rcgroups.com/forums/showthr ... -of-depron

Here is a good place to start looking at the specs and flights of the light weight build. Printer plans can be found early in the thread. You can download either A4 or letter plans. Hans Joachim was the designer and builder of the early versions in 1/9th scale. The skeleton picture shows the light Depron build.
https://www.rcgroups.com/forums/showpost.php?p=6488504

[Neons]

The version I am building as mentioned early on above is a a 1/8th scale with around a 55inch wingspan with an epoxy glass fuselage like John Morgan's build with the hotwired wing halves. Of coarse it will have flaps and retracts as the plane is to heavy for the hand tossing. My build follows John's on page 39 in the RC Groups link above. I communicated with John Morgan if I ran into any problems.
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So here is my first questions I asked John Morgan before my build..
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Hello J.
I am now getting things together to build the FW-190 Dora. I have printed out 2 sets of plans in a 55 inch wingspan. One set will be cut up for templates. I guess it falls into 1/8 scale size. I was torn between making HJ's lighter version or the more robust version that you have built. I am leaning toward the more powerful heavier version though. I think the 55 inch wing is still large and able to carry my gear at a slightly lower total weight. This may translate to less taxing on the motor size and battery size/weight.

I do not have many of the items on hand that you used in your construction. I will have to get them as I go. I plan on starting the fuselage blocks within a day or so. There will be very little documenting as I build as you have already done that. I am planning to use retracts in this plane also.

I have a few questions on your recent build. I hope this does not take much of your time.
The air scoop you built is hollowed out. I see it as a good useful way to cool the battery and electronics. Is yours functional? I want to place a 4s 4000mah lipoly battery in that area. I plan to make a hatch access from the seam in front of the canopy windshield gun panel forward toward the nose about 6 inches long. It probably will end about the rear of the exhausts and above them. This would take the machine guns in the hatch also. The battery weighs 15.0 oz. I would also have to build in air exit slot under the fuselage.

By having the hatch above and slightly forward of the wing leading edge, will this effect the CG very too much? I will use a "Clark Y" airfoil also with 2 carbon 1/4inch shafts for spars. The Depron foam wing will be glassed 0.7oz cloth if use a built up construction. But if I do a solid Pink foam wing I will use WBPU/ 0.7 cloth finish. Of course the weight calculations will determine which way to go. Any comments here are welcome?

Your spinner flew apart. I hope the thin washer behind the propeller will solve the problem. I want to do similar to that. What about a cloth/epoxy skin on the foam to make it more solid?

Your wood wing saddle, firewall, and formers were bonded in to the glass fuselage. What gives the best bond of the wood to fiberglass or epoxy? I was always told the epoxy bonds to fiberglass well. Fiberglass resin does not bond to cured fiberglass well. At least what I found in the boating industry. Is Uhu por glue really good? I have never used it.

Sorry for the long wind. I just want to pick your thoughts on the final finish of your Dora before you get involved in a new build.
Thanks to you and Hans Joachim for the great build presentation you did in this thread. I have learned a lot here.
**Neons** Bob
~~~~~~~~~~~~~~~~~~~~ Reply.
Hi Bob,
The scoop on the side is NOT functional. My battery was placed forward of that and I didn't see any way it would help to make it operational. But if your batt is behind it then by all means, it would help. I have cooling holes in my firewall that flow thru across the battery and the esc. It will need an exit slot. I haven't cut one yet because it is so cold. That's on my list.
My battery is accessed from the bottom. Please excuse me but I don't like top hatches. If the seam isn't perfect, that is all I see.
Where you place your battery has no effect on CG if the plane balances with your chosen location. The battery is just the heaviest thing we normally put in these planes and so its placement is usually critical.
As far as wings, mine is built up balsa, carbon tube , and Depron. It is strong and would handle retracts if hard points were put it. Either way should work.
The spinner is difficult to balance with paint and glassing is even tougher.
I used Gorilla glue( polyurethane) for all the internal bulkheads. Works great but epoxy would work too.
Hope this helps, don't worry about asking, it's no problem.

J

[Neons]

Feb.2, 2009
My plug is almost fully shaped for the glass fuselage. I am in the lighter grit sanding now and eyeballing the shape. The dust is bad. I am outside doing it. We got a 50 degree day here after a tough January. Maybe in a couple days I will have the plug smooth enough to do the fuselage. It looks very nice. I ordered the glass cloth from Thayercraft. He has great prices with free shipping.

Feb. 3,2009
Not much done today due to a time restraint. I spent time messing with the canopy , gun cover, and tail fill sections. I also did more light sanding. At the end of the day I gave it a coat of waterbase gray primer and hung to dry. The foam consists of 2 pieces of green 2 inch thick central layers and 2 pink foam pieces 3/4 inch. They were glued together. The 2 color foams worked good in the sanding as I could compare the lines to make them equal while sanding.
Tomorrow I think I will spackle some more and give it a layer of 0.75 oz cloth and let it dry. It needs to be made a bit harder to continue smoothing out. I accidentally bruise it moving the fuselage around. The cool work area does slow every thing down. Drying time takes much longer. It may be a few days before it can be glassed for the hard smoother surface. I may use some heat to accelerate it. In the meantime I will work on other parts like the cowling.

In the next photo I made a rotating stand today like J's. I like it very much. It holds the fuselage steady as rotated. I will have plenty of use for this later on. I got 2 more coats of Waterbase PolyUrethane on the fuselage also over the primer. It looks gorgeous.

[Neons]

Feb. 14,2009
Here are a few progress pictures. The worst is over now. I spent a lot of preparation time to get the fuselage done. The cold air kept things at a slow pace. I cut the fuselage off the mold today and it came out very good. ''It's Alive !!!" I used Seline glass cloth 3.0 oz. in 3 layers and a bit less than a quart of epoxy. The weight is 22oz. as it came off the mold. I did more sanding before I removed the fuselage and I have to bond the release cut underneath tomorrow. More sanding.

The cowling has been done for about a week now. I cut the wings last week and did some rough sanding. It has carbon arrow shafts in the middle. I am laying in the servo wires next. The spar will be closed up and faired in. I still have some wood to put in the tips and ailerons.

I got my wheels and retracts came in also. I am considering putting in the flaps also. My landing area is not to long and they will help me zero in on the field. I may also add a shorter 1/8'' CF rod in the flap area too. The wing will be covered with 0.75 oz cloth and WBPU. Things should start moving faster now that the worst part is over. My new Turnigy motor, props, 4s 14.8V 4000Mah Lipo, and 60Amp Plush balanced ESC came in. Pretty well all I need.

[Neons]

Feb 19, 2009
Here is where I am at since the last report.
a: I installed the plywood firewall.
b: I mounted the motor and made a wooden extension on the mount to push the motor forward so the drive plate is past the cowling for clearance.
c: The cowling was mounted, trimmed and dowel pinned. I have to add magnets yet.
d: A 3/4 inch foam former is installed forward of the wing with a battery box floor.
e: The fuselage was cut for the wood wing saddle and wood installed to fit the wing.
f: Carbon fiber arrow shafts installed above the wing saddled longitudely for lateral strength.
g: 4 more foam formers installed behind the wing to the tail.
h: Light coat of gray vinyl primer on the fuselage. Made for plastic an flexible surface adhering.
i:The wing carbon fiber spars and joints bonded with some dihedral.
j:All wood trimmed edges have been installed to the wing, tips, and airlerons where necessary.
h: Airleron servo extension wires installed.
i: The wing is rough fitted to the fuselage but not bolted yet.

My next few things maybe tommorrow.
a:Mount screw blocks for the wing saddle.
b:Sand and fill the wing. Then WBPU the surface with 0.75oz. fibreglass cloth. 2 coats.
c:Setup flaps and airlerons.
d:Mount the wing.
E Setup retract landing gear.

Later in the week I hope to cut the cockpit out and Vacu-form one. Cut the rudder out. Make a foam one. I hate to do it, but I am cutting the nose for a battery compartment top loading. Eeek!!!

[Neons]

March 1, 2009
I got a bit more done today. Today I am fabricating a steerable tail wheel. I got my aileron servos and flap servos installed. The wing is in nice shape with the glass cloth and WBPU paint. I have it in primer now. I still have to do the retracts also. I hope to install the tail wheel today. I have the wing fillets smoothed and epoxied in place. I should be able to sand them tomorrow and prime them. The epoxy takes a long time to set as it is in a cool environment

I still have to do my canopy and battery hatch. I am watching you build your spinner too. Your spinner looks nice and ran smooth. That has yet to come for my plane also. I need 2 spinners. 2 blade and 3 blade. I am considering an aluminum machined backplate with a step and a center screw tapped into the prop shaft. Remember the old Veco aluminum spinners? They had an adapter shaft to fit the threads ahead of the prop nut. I have a few pics from yesterday and today so I may post some later or tomorrow after I sand and prime the fillets.The wing fillet is epoxied and setting up for sanding tomorrow. I did get the servos mounted in the fuselage for the rudder and elevator. The tailwheel was made and installed also. Works nice and not heavy either. I have the cut off belly pan to fit to the wing and fuselage bottom to do yet.

It looks like I can tackle the canopy and battery box finals next. I may have to make a larger vacuum form box also. The canopy may not fit in the one I have right now. Only a slight setback in time. I can use a bigger one anyhow.

I hope to mold a pilot soon. I only have a US pilot on hand. I guess it will have to be reworked.

[Neons]

I spent the afternoon in the kitchen making my mess as usual. I made 6 canopies and each one had flaws. The worst of the flaws were dimples the size of a pin head. They looked like rain drops on the finished canopies. I tried 3 different thicknesses and still had the marks. The thinner one in the picture has them but not as bad. I think the heat was to high. I have to get a thermometer. I may try again later in the week with less heat. My wife was not happy to say the least. I need to send her out for the day on some mission. Then I got a note from a reader: Put a metal cookie sheet in the oven to deflect the heat from the heating element . It will let your petg heat evenly. at 275 degrees in my wife's oven it takes over 2 min. to get a 2" sag. without the cookie sheet I get the same dimples you are getting.

The fillets came out nice also. I used the cutout from the fuselage bottom section under the wing and installed it with screws. The top of the landing gear servo will be under the cover. I have yet to get those installed. I am cutting out the battery compartment next.

The battery hatch took some time to fit right. I am satisfied with it. I used a thin Dremel cutter very carefully and used balsa trim inside for a snug fit and also used magnets.

I have made the 2 blade spinner here and will make a 3 blade spinner later also. That one will have a machined step on the back plate to fit the opposite face on the spinner. It will be like a male and female "V" cut. It will be keyed so there will be no need for pins. The center screw is drilled and tapped into the prop nut cone.The center screw will pressure the cone down against the backplate. I also have added cowling vents, intake oil cooler,machine guns, and wooden exhaust tips.

[Neons]

March 19.2009
I worked a couple days scratch building the cockpit interior and casting a pilot that may be satisfactory for this plane. The casting was not perfect and I had to fill with Cyano and kicker to build it up. So it did outcome well enough to be used despite it was a USA pilot. It is just a bust of the pilot figure. I guess tomorrow I button it up if I do not fly with the good day predicted. I will at least seal up the canopy and continue on building so I can show another updated picture.

[Neons]

March 20,2009
Here is the latest work on my Dora 9. There was a lot of time dedicated to getting my landing gear installed and working. These retract units those that Hobby King had in there stock. They are a clone knockoff of another brand. I could not set them deep in the wing root without coming through the wing top skin. I used the HC Lite weight wheels also. I ground them down on the lathe to round them off and narrowed the hub 1/8 inch also. The wheel tubs are aluminum cat food can sides. The base floor is plastic sheet. The wheel covers are aluminum house flashing. I drilled and tapped the back side of the axles for small screws that go in to the strut. These hold the bottom of the wheel covers. The top is a special 2 part aluminum bolt through the strut coil spring. I could have used a hard rubber or wood with self tap screws through the coil also. The servo is a metal gear Tower-Pro MG995. It has good thrust but not quite as much that I would like to have. I am getting closer to painting soon.

[Neons]

April 5,2009
Hello to all of you following this thread. I thank you for your patience in waiting for my final finish pictures. I shot these this Sunday morning and edited them over a few hours. The first picture is from the builder of a fantastic plastic model that I decided to follow in painting my FW-190-D9. Thanks to Brett Green at this thread:
http://hsfeatures.com/fw190d932bg_1.htm

I have a large group of pictures showing every angle and the detail in my paint job. This is the best I could do with my skills which I hope to further improve over time. I may note in some pictures what I can in the regarding what I did. The paint is all Walmart WallyWorld Craft Acrylics blended to shades.

Low visibility rivets and panels show on the plane. Shading was used on the whole plane.

I took this shot just as the temperature change started to fog inside my canopy. You may notice it in other shots.

[attachment=0]FW-190-D9 Finished Plane (6).jpg[/attachment

April 9,2009
Well here is today's finish of my foam spinner. While the glue dried on the 3/8inch drilled dowel bolt post I started to make a bomb. (A fake one). Today I cut the plywood out for the 3 blade prop and gave it 5 coats of white acrylic paint. Then I taped and did the spiral black. I think I will over spray the whole spinner with satin poly after as the flat paint gets dirty too easily. I have it fitted to the plane now as seen in the picture. I have to mount the bomb with some magnets so it breaks away or so it can be easily removed for maintenance if needed. I will post the video soon as I compile it from the maiden. I can say my FW-190 D9 is done then.