Tutorial Advanced - Orta Saint - Hubert G - 1

[Gearup]

This will be a longer post over a period time.
Drawings and wood Orta Saint - Hubert G - 1
The Orta Saint - Hubert G - 1 is a small monoplane from the 1930's. The plan, with the story, came from my son-in-law  It is a Belgian design and was flown as a sport plane. This particular model interested me as it turns out, my son-in-law's grandfather ( and thus my grandsons great-grandfather!) owned and flew it during the 1930's and had some noteworthy adventures with it.

This address will bring up lots of photos of the aircraft type and variations.

https://www.google.com/search?q=orta+saint+hubert+g1&client=safari&rls=en&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjX9dyY_KH4AhUkGTQIHRKKB1MQ_AUoA3oECAEQBQ&biw=823&bih=1033&dpr=1

The airplane is a parasol wing, three seat, open cockpit style with a five cylinder radial engine. Given the period the airplane came from, it looks remarkably modern in design. The engine case is nicely streamlined with a cowl. The fuselage and empennage (tail section) are of a modern shape. The landing gear, however, is designed with large vertical struts attached to the wings and axels, that usually result in a weak point.
When comparing the 3-view plan with several pictures of the actual aircraft, it was apparent that the plans are an earlier model. The plane has a clipped rudder and fin and is missing a headrest for the aft cockpit. Using the pictures as a guide I drew in the appropriate curve for the fin and rudder top along with a head rest. Also cockpit openings were added to the top view.

There is no centre line on the fuselage top view, so I marked one out on the plan using the centre of the propeller shaft and training edge of the rudder.

[Gearup]

Preparing the plans picture: 3 view master jpeg

I used my computer with the program INKSCAPE, which is an open sourced (free} download from https://inkscape.org , to scale and draw in the missing components. There is a bit of a learning curve on the software. Another method to scale you plan using the computer is to print the jpeg of the plan and set the reduction in print size to fit the scale you want.

Speaking of scale, there is a great app I use called "Model Scaler". You enter the dimension of the prototype (real world size), enter the scale desired 1:48 for this model and the model dimension is given as a calculation Use whatever measuring system or even mix them to get the results you want to work with. Of course you can always calculate the size manually.

I use 1:48 for small aircraft such as this as I find it is a bit easier for me to get the details I want yet does not require much material. I primarily use the wing span as the main measurement to set the scale size. It seems that dimensions given can vary for the fuselage and height due to ambiguous reference points, but the wing span measurements generally are accurate tip-to-tip.

This aircraft span is 9.98 meters. 9.98/48 = .208 m = 8.189 inches. If the plan is shrunk to provide a wing span of one of those dimensions ( metric or imperial, pick one but remain consistent) the remainder of the components will set to the proper scale as well. In some drawings the fuselage length is different from the side compared to the top. Take an actual measurement from the drawing side view and compare the same points on the top view. They should be the same, but small variances can be tolerated.
I also draw a one inch square on the drawing before it is printed. this will ensure that what I had drawn on the computer, prints out to the right size on the paper.

Once you ware satisfied with the drawing, you will need to print several copies. During the construction, you will need to cut out the desired view to use in cutting out the wood blanks.

[Gearup]

Wood block selection

WARNING: UNDERSTAND ALL SAFETY PRECAUTIONS, USE SAFE TECHNIQUES AND PROCEDURES FOR THE PARTICULAR TOOLS IN USE AND ENSURE THEY ARE APPROPRIATE FOR THE TASK.

The model will require at least two blocks of wood; Fuselage and wing. The tail components can be cut from scraps of thin would as desired.

I tend to use three types of wood for my models. Spruce, bass wood and maple.
The spruce is from construction 2x4 where I look for the straightest and finest grain in the wood. You only need small lengths so even if there are large knots in the board, it may be possible to find the choice wood in the clear sections. The entire model can be made with spruce, which carves and sands nicely

Bass wood is a bit more exotic out here on the West coast of Canada and it is shipped from the eastern part of the country. It is more expensive, but generally the wood is of high quality, dry, straight and clear of knots. It works very well with all tools and can be used for the entire model if desired.

Maple is a very hard wood that is not too expensive here and the pieces available are usually of nice quality. Its strength and hardness make it difficult to work with hand tools. Powered machine tools work well. It can be used to make small parts that need to hold detail or are thin and need the strength. I use maple for tail surfaces as they are usually quite thin, small propeller blades, struts etc. It can be sanded to razor thin if needed and still be strong enough.

Of course, most any wood can be used, mahogany, balsa, yellow cedar  even plywood for some parts. Usually what ever is available in your area can be used.

[Gearup]

Block preparation

(IMG_9779.JPG)
All of the blocks I found for this model were cut off from previous projects. Hand saw, band saw, scroll saw or table saw can be used to make the rough blocks

Construction 2x4 are actually 1-1/2 x 3-1/2 inches in section.  The fuselage needs a minimum height of 1" and a width of just over 5/8" and 5" long. Cut a piece 10" long from the section of 2x4 free of knots and cracks. To make things simple, cut (rip) the length down the middle so you have two pieces 1-1/2 x 1-1/2 square  x 10 inches long. Top and bottom should be parallel to each other and square to the sides which are parallel.

Looking at the end of the square block, note the direction of the wood end grain. Up and down (I) called vertical grain, diagonal across (/) is quarter sawn  or flat sawn left to right (-). Vertical grain is preferred as it gives pretty much the same grain pattern on the sides as the top/bottom. If you have vertical grain, orient the block so the end grain runs up and down.

My fuselage block is 1-1/4 x1-1/4 x9 inches. Setting over the fuselage outlines, it covers them completely indicating that the model will fit.(IMG_9771.JPG)

The wing block is basswood as I had a small piece that was the right size, 3/4 x 3-3/4 x 8-1/2 long. there are a couple small knots that are located on the face, but will be cut away. The working blank will be 5/16 x 2 x 8-1/2 and so must be cut from the block. i marked a line the length of the block 2" from the edge to exclude the two little knots.
(IMG_9788.JPG)

I then marked a line 5/16" from the top of the wing block which will also be the top of the finished wing. Saw the thin piece from the block keeping the thickness at least 5/16 for the whole cut. Grain direction for this block is probably going to be flat grain, but this is fine.

The maple scraps are 1/4 thick and cover the stabilizer and rudder so they will be used as is .

[Gearup]

Marking and applying paper templates to the fuselage blocks

I generally cut the fuselage blank first, then the wing and then the tail surfaces. In this model, it is easier to cut out the wing and tail first as they make good practice using the tools.

It is important for the fuselage block to be square and parallel as this will make cutting out the profiles easier and more accurate.
Coping saw, band saw, scroll saw can all be used here.

(IMG_9768.JPG)
Mark the centre line along the top surface.  I used a small marking gauge or use a pencil (HB) and a straight edge to make sure the line is straight and parallel to the sides. Slightly off centre either way is not too critical at this point.
Now mark a line on the side parallel to the top. You will notice a line running fore and aft along the fuselage of their model. This is a feature on the aircraft that can be used as a longitudinal reference to align the pattern on the block. Position it not too high or too low. On some drawings there is a theoretical line depicted that is used as a reference for the aircraft and should be used for aligning the pattern. It may be significantly above or below the centre of the block.

Now take a paper drawing and cut out the top view of the fuselage. Contain the outline  centred within a rectangular box the width and length of the block. Set the pattern on top of the block aligning the centre lines. It should sit neatly on the top of the block. This is a dry run and if it all fits well it can then be secured to the block.

The pattern can be secured with a thin layer of wood glue, rubber cement, double sided tape, spray photo mounting adhesive or what have you along those lines.
Apply the glue and be sure the centre lines line up then press the template on top of the fuselage.

Let the glue dry for a few minutes. If the template overhangs the sides of the block, trim them away using a sharp knife. Leaving the edges overhanging the block will cause problems when working on the sides.

(IMG_9782.JPG)
Look at the top of the pattern and note where the leading edge of the wing crosses the fuselage centreline . The leading edge also appears to coincide with the aft edge of the cowl as viewed on the side view. This will be a reference point. Take a sharp awl or similar tool to make a counterpoint mark at the intersection of the leading edge and centre line.

IMG_9783.JPG
Now on the side of the wood block, mark a line straight down to indicate where this point is on the side. It should intersect the side reference line and this will locate the side template  fore and aft at the cowl line

Do the same procedure to mark references using the leading edge of the horizontal stabilizer at the intersection with the centreline and mark a line down to provide a reference point at the tail.

Now cut the template from the plan side view and use the reference line to align the template level. Use the cowl line and stabilizer lines to locate the template fore and aft. If all is good, glue and trim the template as before.

[Gearup]

Drilling alignment pin holes on fuselage block

(IMG_9791.JPG) (IMG_9794.JPG)

For this operation a drill press is the best tool. It can be done with hand drills or a Dremel but precision on holding the drill square and vertical s important.

Using a 1/16" twist drill, drill a vertical hole on the top view at the centreline / wing leading edge intersection and also at the stabilizer/ centreline intersection through the block. Roll the block over and drill the holes at the cowl / reference line intersection and the stabilizer leading edge /reference line intersection.

These holes will now allow you to find and redraw the centre line and reference lines as needed when carving. They will also be used to align the wing and tail surfaces during assembly, hold the model when needed and locate features on the model for adding details.

[Gearup]

Rough cut the top view of the fuselage (plan view)

You may notice the headrest fairing is above the top of the block. No worry as this will be made from a separate piece.

(IMG_9797.JPG) (IMG_9798.JPG)(IMG_9799.JPG)
I used a band saw to cut the fuselage block to rough shape. Make sure your bandsaw blade is square to the table before starting

Cut the side view of the fuselage out making sure the blade is on the waste side of the lines. Try to plan your cuts to make as few off-cuts as possible as this will help when setting up for the top cut. Sand the fuselage profile to the line of the paper pattern. A belt or stationary disk sander is an asset, but sanding sticks will work. Make sure to keep the sanded surfaces square to the sides.

(IMG_9806.JPG) (IMG_9807.JPG)
Now reassemble the fuselage block using the off-cuts. Once you are sure of the placement of the off-cuts on the block, remove the aft top section and place a couple of small blobs of hot glue on the top of the fuselage. Put the off-cut into position and use a 1/16" pin through the drilled alignment holes to pin the piece on. Before the glue hardens, (seconds!) check that the saw kerf is about the width of the blade to keep the blocks square and that the cut-off is flush to sides of the block.

Attach all the remaining blocks using hot glue and pinning them as able. The fuselage block should now be square again with the paper pattern on the top and (mostly) intact.

[lastvautour]

Excellent tutorial Frazer. I await further posts.

Lou

[Gearup]

Rough cut the top view of the fuselage

(IMG_9813.JPG) (IMG_9814.JPG)
Remove the pins to keep metal away from the saw blade. Cut to the waste side of the lines as before and sand to the lines .

(IMG_9816.JPG)(IMG_9817.JPG)
Carefully pry the waste from the fuselage block using a flexible putty knife. Avoid a sharp blade when doing this. The hot glue should release fairly easily.

At this point you have the fuselage ready for carving the final shape.

[Gearup]

Fuselage guide marks

(IMG_0105.JPG) (IMG_0106.JPG)
Using an HB pencil, connect the alignment holes using a thin, flexible straight edge. Make the mark lightly so as not to create a grooved line in the wood.  Also mark out major features such as the cockpit openings, cowl lines etc. You can free hand the lines on the nose as required. Note that the propeller shaft on this aircraft (and most others) does not always coincide with the intersection of the centre lines. On this aircraft the propeller shaft is slightly above the intersection and was marked with a pencil dot and later with an awl point.

[Gearup]

Fuselage cross section template
(IMG_0107.JPG)IMG_0112.JPG)
This model has a simple cross section that is only shown on the front view. I made a paper template by cutting out the front fuselage section on the plan and then cutting it in half. The rest of the fuselage shaping was done using reference photos from the web.

[Gearup]

Excellent tutorial Frazer. I await further posts.

Lou

Thanks Lou. Building the model is the easy part .

I will keep posting as I complete the tutorial segments.

Fraser

[Boomerang]

Excellent work Fraser. The personal history is very nice touch.

Will follow till completion.

Cheers

Gordon

[Gearup]

Thanks Gordon. I will see the project though to the end too. Just not too fast is all.
Fraser

[Boomerang]

 Fraser ,

Checked out the internet. A very nice looking aeroplane.

Cheers.

Gordon