Dornier DO 18 - (Perhaps another long story)

[bweaver]

I am not that impressed with using the pink foam for this project.  To me, the foam feels softer and chips easily when trying to cut, shape and sand it.  For this reason, I went searching for some more 1/2 inch blue foam.  I found enough behind some furniture to finish the model. (If it had been necessary, I would have hot-wired some if I couldn't find any.)

The horizontal stabilizer was made out of blue foam and reinforced with a carbon rod.  The rear of the stab has a piece of balsa attached for hinging and further reinforcing purposes.  The elevator is made from balsa with a plywood piece was added to bottom of the centre section for reinforcing purposes and for a secure place to secure the control horn to.

The vertical stab and rudder are also made of blue foam board, with balsa reinforcing and plywood pieces installed for securing the control horn as well.  These components are yet to be shaped, because I need the straight edges for alignment purposes. 

I will be fiberglassing the wing sections, sponsons and tail control surfaces before final attachment to the fuselage and center wing section to the pylon.

I am likely going to install the receiver midway up the pylon so that it will be easy to get to for future servicing. A hatch will be incorporated in the side of the pylon for access purposes.

The photos below should be self explanatory.  (The model's components are just sitting in place and T-pinned where necessary for the photo op.)

[Michael]

That's really looking good!

[bweaver]

The horizontal stab and elevator have been hinged and fiber-glassed. Then the stab and elevator along with the vertical stabilizer were permanently installed using similar techniques to those of Frank to hold things in place and to true everything up.  (When all else fails, I also believe in the use of trim tabs as well.)

The bulkhead external templates were used to define the upper outside upper surfaces of the fuselage.  A fine dollar store file was used to define the shape of the fuselage at the bulkhead locations.  Then a sharp utility knife and coarse Dura-grit filing tool were used.  (While looking rough, the fuselage is starting to shape up.) As noted previously the bottom of the fuselage will be the last to shape.

The top pieces of the fuselage are pinned in place for now for the photo op.

The top pieces of the fuselage will be permanently glued in place after the rudder, water rudder, pushrods and servos are installed.  After that, the remainder of the fuselage will be shaped to a point that I will accept and then be fiber-glassed.

[Michael]

Again, really looking good!

[bweaver]

Refer to the last photo - For the water rudder mechanism I am using a standard type of nylon steerable nose gear device, mounted on two pieces of plywood with a reinforcing piece of foam block.  The two pieces of plywood were sealed with varathane before assembly.

A plastic sleeve for housing the rudder wire shaft is epoxied into the base of the hull.  The plastic sleeve abuts up against the bottom of the nylon nose wheel component. The wire rudder shaft slides through the sleeve. The control horn for steering is firmly secured to the wire shaft and another collar is attached at the top of the rudder shaft to provide a little more security in an attempt to prevent the rudder from falling out during flight.  (If it does, I will be disappointed.). I believe this type of rudder steering mechanism will reduce the likelihood of water entering the hull, as a result of the top of the sleeve is situated well above the water line.

I hope this explanation makes sense to the reader.  I also hope my logic reduces the likelihood of water infiltration is effective in practice. (We'll see.)

Now onto the progress involving the other rudder and horizontal stab.  The rudder has been fibreglassed and the control horn and hinges have been attached.

The horizontal stab is in the process of being fibreglassed before the rudder will be attached to it.

Refer to the photograph of the actual aircrafts hinging mechanism.

After finding the above photo of the original aircraft hinging mechanism, I have decided to change flap and aileron hinging design from that which I had previously proposed. (I felt that the bent wire method proposed before to hinge the ailerons and flaps will not provide sufficient strength and the appearance doesn't look very realistic.)

The drawing in the second last photo illustrates what I propose now. I think this method will be far more effective and similarly reflect the aircraft's hinging.

(Time is moving on.  Only 54 more days to finish it up for flying off the lake.)

[bweaver]

This week was the first time I have flown again and been at TEMAC since last fall.  It was nice to get back into the air again.  Gets the juices flowing...

I saw Michael there as I was leaving and the afternoon shift was arriving.  When discussing our winter projects, Michael gave me a funny look about my response after asking me about the progress on my project.   (I advised him that it was slow as usual and I may not have the model painted before it is maidened hopefully later this spring.)

This brief meeting has spurred me on once again get on with it.

The water rudder and tail rudder have been permanently installed.  The elevator and rudder servos have been installed.  The water rudder and tail rudder have separate pushrods to control them.

The center of bottom of the wing has been equipped the flaps that are hinged. The flap servos are also installed.  Wiring channels have been cut out in the center wing section to accommodate the flap and aileron wires that will be run to the pylon where the receiver will be installed.

The outer wing sections will have similar wiring channels cut out and the aileron servos will be installed.   

The count down for the project continues.

[Michael]

Nice! I love seeing these amazing projects take shape!

[Frank v B]

Look at all the blue and pink foam.  Just realized I could charge it off as a business expense.
Much easier than my attempt to get "John's Hobbies" to change its name to "The Balsa Lumber Store" so I could claim it as a business expense.

The model looks great.  Because it is larger it should be easier to fly than your previous in-line twin seaplane (Savoie M).

Frank

[bweaver]

The dropped hinge arrangement reasonably simulates the flying ailerons and flying flaps as intended. 

Moving right along...

[Wingnutz]

Bruce, a really interesting build and a great write-up! Hope this "long story" continues!

[bweaver]

Thanks Bill,

It will continue...

[Wingnutz]

Glad to hear it! I'll be watching for it.