Savoia Marchetti S55X (round two a never ending story)

Started by bweaver, October 18, 2019, 03:26:58 PM

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bweaver

This is the second Savoia Marchetti S55X that I have built.  The first was constructed of built up balsa wood.  If you are interested in that build go to http://temac.ca/smf/index.php/topic,4454.msg26337.html#msg26337

The original had a 40 inch wingspan.  It was scratch built from an old set of plans originally intended for a control line stand-off scale model of the plane.  It flew with some success, but I think that the plane's weight and small wingspan had its limitations.

This model is going to have a 60 inch wingspan.  I downloaded from AeroFred at https://aerofred.com plans for a 50 inch wingspan model of the plane.  I took the downloaded file to Staples where I had it expanded and printed at 120%.  Thus a 60 inch wingspan version can be constructed. A copy of the plans are attached below.

After looking at the drawings, you can see how I should build it with balsa wood and ply.   I'm not doing that again! 

I am going to use these full size plans as a guide to help me construct this model out of foam, depron, ply, spruce and some balsa where necessary.

My objective for the model is somewhat simple.  It must fly from water.  (Is that two objectives?)  Anyhow the model will have to be strong, water resistant and float.  I think I am using the right material to help it float anyways.

Initially I thought I would build the wing first, but after reviewing the plans over and over and over and over again, I have decided that I am going to build the twin hulls and the affixed booms first.

Then I will proceed to construct the center wing section, motor pylon and cockpit, horizontal stab, vertical fins and rudder control surfaces, followed by the two outer left and right wing sections.  Some where in between I will install the motors, ESCs, battery compartments and water resistant hatch covers, receiver, servos and batteries.  Oh yes, then finish the model in its original color scheme.

Let the construction begin!






davidk

That 60" wingspan is going to be a stunner.  I agree that it's 2 objectives... that it must fly... from water.  ;)

Thanks for the link to your last build... and to AeroFred.  I think there might be a 3D printer somewhere in my future.

piker


msatin

Looks Awesome Bruce
Please post build pics as you progress
I would add a 3rd objective...Land on Water
Which is actually a contradiction in terms.
How can you "land" on "water"?  ;D
You never fail until you stop trying

bweaver

Quote from: msatin on October 18, 2019, 10:33:51 PM
Looks Awesome Bruce
Please post build pics as you progress
I would add a 3rd objective...Land on Water
Which is actually a contradiction in terms.

How can you "land" on "water"?  ;D

Thanks for the nice comments.

I do intend on documenting the construction with photos as I proceed.

@msatin regarding your comment about the third objective 'Land on Water' isn't it a contradiction in terms?  I have done it. I accomplished this by nose diving my original Savoia M... into shallow water from a high altitude.  The plane easily penetrated the water and continued to plant itself in the bottom of reservoir before popping back up to the surface with mud attached to the front of each twin hull as evidence of this spectacular feat.

Now on with the build.

I have modified the bottom keel and top rear keel of the twin hulls from that shown on the original plans.  This modification will serve multiple purposes.

First- The new design will be used for strength and for accurately securing the twin booms to each hull individually.

The one piece top and bottom keel consists of 1/4 inch ply, with portions of the ply cut out and lightening holes drilled in the rear portion to lighten the structure, but still retain its strength.

The first photo shows the original hull and keel design.

The second shows my tracing skills, and the sections I intend to cut out and the lightening holes I intended to incorporate.

The third shows show that I can cut the paper template and place it on the drawing. (Real neat huh? Don't worry I am using safety scissors.)

The fourth photo shows the finished keels and spruce booms with cut the ply portions cut out and lightening holes drilled into the rear portion.

The booms are not permanently attached yet, but will be once I add the brass fitting to the top and bottom of each boom and epoxy and solder in the music wire staples.  Once this is done the booms will be permanently attached to the each hull and be perfectly aligned.  (I hope)

Maybe this makes sense?

davidk

Love the level of detail... thanks Bruce.  And that little saw is just about the cutest I've seen.
Did you cut the ply by hand... or with a power saw?

bweaver

Quote from: davidk on October 22, 2019, 07:47:37 PM
Love the level of detail... thanks Bruce.  And that little saw is just about the cutest I've seen.
Did you cut the ply by hand... or with a power saw?

It is interesting that you ask @davidk

The first photo depicts the cute little saw that you were asking about.  It is a Stanley SHARPTOOTH FINE FINISH saw.  Very nice little saw that cuts wood rather than tearing the wood apart.  It leaves a clean cut finish on the surfaces of the wood that has been cut. I use it for straight fine cuts.

The other three photo's depict my homemade bench saw I built for cutting ply, balsa and other pieces of wood.  This table saw consists of a jigsaw mounted upside down on a little table I constructed for the purpose of supporting the saw and the wood I am cutting.  This table saw allows me to cut and shape wood easily. It is easier to use than a jigsaw for my hobby purposes. The wood is moved through and around the blade as desired. The shoe/base plate of the jigsaw was removed and is attached to the side of the table for use in winding the power cord around when the saw isn't in use.  The saw is turned on and off by using a switch on a power bar that I place beside the work area. 

The tool was very inexpensive to make and is very convenient considering I don't have a workshop.  I keep my little Shopvac handy for quick clean-ups while in use and afterwards.

PS - I have yet to loose a finger while using it.  If you can use a bandsaw, you can easily use this saw.

davidk

Those are a couple of fine tools.  Big thumbs up on the topsy turvy jig saw... that's a sweet idea.  If we had a thumbs up emoji here on the board... you'd get 2 on this post.
Gotta respect a man who makes his own tools... or to quote another TEMAC member... make it something you want it to be.

bweaver

Quote from: davidk on October 23, 2019, 04:11:23 PM
Those are a couple of fine tools. Big thumbs up on the topsy turvy jig saw... that's a sweet idea.  If we had a thumbs up emoji here on the board... you'd get 2 on this post.
Gotta respect a man who makes his own tools... or to quote another TEMAC member... make it something you want it to be.

@davidk  It's not a topsy turvy jig saw,  just because I mounted it to a table arrangement upside down. I know some people will have a problem with the concept.  Think of it this way, using a jigsaw in its normal configuration; the blade goes up and down.  Using the jig saw in my inverted tool, the blade goes down and up.  Same excellent cutting results though.

Construction continues:

Photos 1 & 2 - Instructions and illustration for bottom boom and hull keel permanent attachment method.

The pinching technique of the brass tube as outlined in the plans instructions wasn't worth a hoot.  Alternatively, I cut the brass tube down the center with my Dremel, then pinched it and soldered it.  Two dry fit brass fittings of this nature were made.  The two fittings were epoxied to the boom ends after drilling the ends of each boom for insertion of the piano wire.   

The piano wire was cut using the Dremel.  The wire was also scored using the Dremel to ensure the epoxy will hold securely to the wire when glued in place in the spruce boom and keel locations.  The bottom booms and keels were drilled out carefully for the piano wire to be inserted and epoxied in alignment.  There are now two identical booms and hull keel frames ready for further construction.

The remaining photos are somewhat self explanatory, but...

The hull bottom was traced on paper for making a paper template.  Two full size hull bottoms were cut from the foam.  The bow (front) bottom portion was removed from the 'C' bulkhead forward.  Note:  A ¼ inch portion of the center was removed to make up for the ¼ inch ply keel. The two remaining pieces were cut into 4 pieces.  Two front pieces [left and right sides] to facilitate the front of the hulls' bottom and the 'step'.  The two rear pieces [left and right sides] facilitate the rear bottom of the hull behind the 'step'.)  The step portion was reinforced with 1/8 inch ply.

(For those who might be interested, the 'step' is that notch or step in the bottom of the hull. The rear bottom of the hull slopes upwards behind the step allowing for the aircraft to rotate during take-off and landing without the back of the hull digging into the water. Digging in increases drag, which will prevent lift-off.)

A paper template was made of the side wall of the hull.  Two outside hull walls were cut from foam and two inside hull walls were cut from foam.  The inner hull wall wing saddles are larger than the wing saddles on outside walls of each hull.

Note: A solid piece of foam board will not bend easily, so the front and rear sides of the hull were scored partially through the foam with a saw to allow the foam to flex. 

The bottom four pieces of the hull were glued on first.  Then the sides were glued to the bottom.

The second last photo depicts the tools and adhesives I have used up to now.

The two hulls at this point don't look pretty, but they will get there. Just imagine...



bweaver

Photo 1- foam blocks installed for start of bow construction.  Balsa bumpers will be mounted on each side of the keel and everything to be sanded to shape.

Photo 2 – note the plywood keel extensions fore and aft coming out of the bottom of the hull.  The reason for these extensions are explained next.

Photo 3 – the plans have a reference line drawn under the side view of the hull.  The keel extensions sit atop this reference line and will keep the hulls in alignment for measurement purposes and alignment purposes during assembly.  The extensions will be cut off after final assembly and before finishing the model.

Photos 4 – More tracing, then cutting out of the two plywood sides of the pylon legs

Photo 5 - The two sheets of the plans are taped together so that I can start the construction of the center wing section between the hulls. 

Photo 6 - I cut and shaped multiple ribs 01 and 02 for the construction of the center wing section. 

Photo 7 – depicts the rough shaped center section that at this time is just taped in place for the photo.  Note that the center portion of the wing has been hollowed out to facilitate the wiring of components. 

Photo 8 - The center section at this point consists of 4 separate parts.  The four parts will be attached together after the pylon leg anchoring features are installed.

piker

It's looking great, Bruce!

You're providing an excellent build log as reference for other builders and wanna-be builder to see how to create interesting models like this.

Robert

bweaver

@piker Thanks Rob.  This is another experimental project on my part.  I enjoy the tinkering, adjusting the use the foam board and similar mediums as alternatives for this build.

Getting on with the construction, the next step was to make the twin motor mount pylon out plywood. 

Photos 1 & 2 – Using the plans again, a template is made for the pylon motor mount. Then using my topsy turvy jig saw the plywood base was cut out.  The notches where the three pieces will intersects and be attached were cut out with a hobby chisel and hammer.  I use a sharpening stone to keep my chisels, blades and cutting knives sharp.

Photo  3 - Next, I shaped the airfoil of the pylon leg structures.  This was accomplished using my 'Dura Grit' file, 'Dremel' power tool for corners and sand paper to finish.  The photo shows one pylon leg shaped and the other, not shaped.

Photo 4, 5 & 6 -  Using the plans again, a foam template was made for forming up the pylon angles.  Note that I measured to make sure everything was right.

Photo 7 – Using 15 minute epoxy, clamps and assorted tools, the pylon assembly is rubed together.  I'll let it cure overnight, before using the pylon assembly for establishing the pylon leg anchor points in the center section of the wing.

davidk

If the lines on that table top could talk... each cut part of airplane.

bweaver

Quote from: davidk on November 05, 2019, 11:04:29 PM
If the lines on that table top could talk... each cut part of airplane.

This table has served the family faithfully for many purposes.  Yes, 99% of the cuts, gouges and drill holes you can see are related to my model aircraft hobby activities. 

David,  you have to understand that when this table is needed for a family overflow dining activity, there's nothing a table cloth won't cover.   :-X

Wingnutz

#14
Bruce,
I am impressed! Beginning to think of you as Mr Warwing, but for me, this is way better! I missed what happened to the first S55X (such a cool airplane!) ....or is that a closed topic?
Anyway, well done!
BTW,  In order to lend a Canadian flavour to your build, I could bring a Canadian beer can to the next pilots' meeting to replace the A&W thing...do you need a regular size, or tall boy?
Cheers,

Bill
DOWN WITH GRAVITY! UP WITH LEVITY!