Savoia Marchetti S55X (round two a never ending story)

[bweaver]

Well it has been a couple of months since my last post involving this aircraft construction thread. 

It isn't that I haven't been working on the plane, (most part bull) it's that the advancements haven't been worth pointing out up to this point (yeh, that sounds good).

So let's catch up. (let's get going)

I have shaped the hulls by trimming away larger pieces of foam with my trusty utility knife and by filing away foam with my DuraGrit medium and fine files.

I have Gorilla glued the center wing section to the inner wing saddle of each hull and to the center plywood former/boom assembly. This makes a water tight joint at the wing saddles. (refer to photo 1)

The outer wings have been glued to the outer portion of the outer center section of the wing with the desired dihedral. (refer to photo 2)

I have Gorilla glued the pylon motor mount struts into the wing center section, securing them to the 2 sets of wooden top and bottom wing longeron structural components provided for this purpose.  (I am using the term 'wing longeron' because the center wing area houses the aircraft's cockpit and in my view would be considered part of the hulls/fuselage portion of the plane.)

The battery wires from each of the ESCs has been fished down the inside of each of the two front pylon struts and then into the wing section leading into each respective hull.   As noted before, the hulls will be used as battery compartments. 

The XT 60 battery connectors will be soldered to the battery wires at later point before gluing the wing sections on.

Each ESCs throttle wire is attached to a Y harness. The one Y harness throttle wire runs down a rear pylon strut into the wing and then into the receiver compartment. (Note: A 'positive red wire' from one of the ESCs throttle wire has been severed to ensure the two motors will respond to the throttle control as one.)

The motors have been secured to the pylon motor mounts with lock nuts and the loose wires and ESCs are secured to the pylon with quick ties.

The ESCs have each been water proofed by filling both ends of the ESCs with epoxy.  I have done this successfully before.  (I know from personal experience that this technique is works, because the motor/ESC arrangement on my Mentor float plane spent a significant amount of time under the water before the plane was retrieved.  Once retrieved, I simply blew the water off of it and the motor and ESC have been running well when ever I have flown the plane since.) [refer to photo 3]

You may wish to refer to the  Flite Test YouTube video demonstrating how easy it is to do. The epoxy water proofing segment of the video starts at around the 9 minute mark on the video.   

https://www.youtube.com/watch?v=s4z8QMgTEA4

The horizontal and vertical tail components have been carved and filed to shape.  Balsa wood has been used to beef up these components and to provide hinge point anchors. 

The elevator has been constructed primarily of balsa, because I determined that a foam elevator wouldn't be strong enough to function on this plane.

I am in the process of fiberglassing each of these tail elements before hinging them.

I have not decided whether to use cloth type or pin type hinges.  Would anyone have any suggestions as to which type of hinge they would recommend for this aircraft? Your suggestions and rationale would be appreciated.  (refer to photos 4 and 5)

Once these components have been fibreglassed and hinged, they will be secured together making one complete tail section.  This tail section will then be affixed permanently to the booms. (The tail section will consist of 2 vertical stabilizers, 3 rudders and the horizontal stab and elevator)

I am constructing the tail section using this method, because I believe it would be too difficult to build the horizontal and vertical surfaces directly on the booms and instill the necessary alignments. (refer to photos 6 and 7)

[bweaver]

All tail surfaces have been fiberglassed.

The photos below should illustrate the technique of how I am constructing the horizontal and vertical tail surfaces as one component for attachment later.

I removed fiberglass where necessary and used a file to remove foam to a depth required to accommodate the shaped pieces of the boom made for this purpose.

The last photo shows the horizontal stab just sitting on the booms. (not permanently attached)

Next steps will involve the positioning of the vertical stabs.

[bweaver]

I used the same process to prepare for the installation of the two horizontal stabs.  Everything in the photo below is just pinned together. 

I am looking for suggestions on next steps?  Would it be suggested that I hinge each component separately, then paint the horizontal stab/elevator and the vertical stabs/rudders.  Paint the components then put together the final unit?   

The center rudder is going to be equipped and mounted with a pivot point and brace running from the horizontal stab up to the pivot point on the top of the rudder. (There will not be another vertical stab in the center section) See photo of the actual aircraft and look at rear tail section.

I'm also still looking for suggestions on the type of hinges to use? 

[Frank v B]

re: input on the tail unit.

If it is going to be painted, I would assemble everything with hinges in place.  If you are using a covering film, assemble after covering.

The main reason is that if it gets painted, you can liberally (strongly) glue everything together and paint over the glue joints.

FWIIW

Frank

[bweaver]

Thanks for the input Frank. 

The aircraft will be entirely fiberglassed and painted at some point.  All the tail elements with the exception of the center rudder are completely glassed.

Before I proceed with the remainder of the tail, I need to get the next steps organized for its completion established. Hinging? Painting now or later?  Combining pieces into one unit?

Other steps include
the remainder of the receiver/electronics installation and soldering,
wing reinforcement,
wing attachment to center wing section,
cockpit canopy construction,
pylon motor enclosure and cowl,
control horns, push rod installations,
remainder of hull construction,
cosmetics and filler as needed,
battery hatch construction with waterproof hatch
fiberglassing remainder of components
painting and trim.

These steps should go along pretty quickly now once I get things for the rest of elevator/rudder tail section construction out of the way.

[bweaver]

I have decided to experiment with the Robarts Pin type hinges. For advice on the hinging matter I went to YouTube.  Lots of pros and cons and how to videos on the subject matter. 

The hinge experiment worked meaning the hinges function and are well secured.  Now to hinge the remaining rudder(s) and elevator. 

[davidk]

I know you're planning on painting, but I think the fibreglassed finish looks really good as is.  The contrast between the blue sheen and the balsa is very cool.

[bweaver]

Thanks David

You can see the balsa wood through the fiberglass.  The fiberglass has not added much weight but the added strength is tremendous.

All painting in the future will be completed in my garage when the construction is completed and the weather is more accommodating.  I will likely add another thin coat of Eze-Kote resin and sand before painting.

[bweaver]

I am experimenting with the design for the construction of the canopy.

I am going to use clear plastic sheeting (from the hobby shop intended for making canopies) for the principle canopy construction.

Based on the drawings of the canopy on the plan and from other sources, I have made a paper canopy as my first kick at it.

There will be 5 pieces of clear plastic making up the canopy.  1 top, 2 sides, 1 front consisting of front 3 windows and 1 rear portion of the canopy.

The aluminum structural out lines of the canopy will be made out of thin depron, painted silver (aluminum colour) then glued onto of the plastic sheeting.

The 5 pieces of the plastic sheeting will somehow be joined together to make the canopy. 

A rough paper canopy has been made to test out making the templates for the canopy pieces.  More of these template canopies will be made until I get the shape right and before cutting the clear plastic sheets.

My first model's canopy was made of ply and plastic sheeting.  See photos at http://temac.ca/smf/index.php/topic,4454.msg37404.html#msg37404
I may have to use this technique again if I don't feel that the depron will work.

I hope this makes some sense of how I plan to go about making the canopy.

Any other suggestions for alternatives are welcome?

[Frank v B]

Bruce,

Go, go.  It's really coming together.

re:  "Lots of pros and cons and how to videos on the subject matter."  That is just proof that it is a totally personal decision.  The only advice is to read about the options, take stock of your tools, your ability and your patience and pick one you think will have the highest probability of success. Remember what we said about our build classes.  If you have a problem with a build, 8 people will give you 10 options.

re: The canopy.  This is a perfect candidate for a balsa sheet and stick built canopy, spray paint it the colour you want, then cover the whole outside of the canopy with clear Monokote.  No seams to leak.  I can give you the clear Monokote.  Try it.  You will love it.  It is a breeze.  (note: My Stinson Voyager, Noorduyn Norseman and Taylorcraft used this method for the windows).

Frank

[sihinch]

Love the canopy idea Frank.

Awesome build Bruce.

[Michael]

In the interest of water-resistance, I would carve and shape the canopy out of solid styrofoam, and then paint to simulate the windows and structure.

(Your paper mock-up lacks the forward angle at the front windows.)

My opinion; sorry if it's different from yours.

[Frank v B]

Bruce,

re: canopy/hatch.

Regardless of which build method you choose, use the model boat design of a vertical combing around the hatch edge that sticks up from the deck.  The hatch/canopy slips over it.  The worst hatch for a boat/seaplane is a flush one as we traditionally build for battery hatches on planes that never see water.  I'll post a drawing....once I warm up my drawing skills.
So much for my drawing skills. 

Photo 79- A great hatch on a Graupner Pollux tug..... for my grandkids to use in our back yard pool....once I am done with it.
Photos 80 and 81- a poor hatch.  On a Dumas PT 109.  Water will funnel into the hull.  It was built this way to allow proper access for starting an IC motor.  It was designed before electric starters became popular. We used to use leather shoe laces to start IC engines.  You needed a wide opening for it.... or we would accidentally widen the opening.

Frank

[bweaver]

Thanks guys for the suggestions and comments.   

I was also thinking about vacuum forming or simply try heat shrinking the plastic over a plug.  (never done that before but I have seen Vic do it with success.)

Based upon your suggestions, I am leaning towards making it out of painted balsa and clear monocote (Frank, what an inspirational source of useless useful information).   I like the water resistance qualities that can be achieved using this technique.   Note that the cockpit area is not housing any electronics, but it would be nice to keep water out of the area anyhow.

I am still undecided?

Regarding water proofing the battery hatches:  The technique suggested by Frank is what I used the last time and it worked great. (Didn't it Rob P?) I think I can make it even better with this model.

Thanks. Now to carry on...

[Frank v B]

Bruce:

re:"(Frank, what an inspirational source of useless useful information)."

There is a first time for everythingone.

F.