Santos Dumont No. 18 Hydroplane 1907 by Greg Davis - Scale 1:16

[Greg Davis]

Toward the end on last year, I became acquainted with a boat that Alberto Santos-Dumont built in 1907. The boat - the No 18 hydroplane, was Santos-Dumont's only watercraft; the rest of his many notable creations were aeronautical in nature. He built and flew many balloons and dirigibles, but may be best known for the 14bis - credited to be the first plane to take off under its own power and flown publicly in Paris. For many years, in Europe and in Brazil (his home country) Santos-Dumont was credited as the first to fly an airplane. Santos-Dumont was independently wealthy and thus had the means to pursue his desire to build and fly heavier than air crafts. Most of his creations where constructed in France where his main residence was located for many years. He also liked a challenge, often associated with a bet. The No 18 hydroplane came about due to a bet that asked for the first boat to achieve 100km/hr along a course on the Seine (averaged over two directions). 

 

No plans for the No18 are know to exist; in fact Santos-Dumont destroyed many plans and notes in 1918 after being accused of spying for the Germans. It is most likely that the plans and associated building notes for the No18 were destroyed at that time. Over in the 'Discussions for Ship Plans and Project Research' portion of MSW I have posted more about the boat and my quest for information. Fortunately, with positive encouragement from MSW members and a number of helpful contacts I have been able to collect enough reliable information that I am confident that a quality model of the No18 hydroplane can be created. This is what I aim to do. 

 

Mostly based on published articles and historical photographs, I have been able to draft plans to build a model in the scale 1:16. The model will be just over 24" long, the main hydrofoil gives a width of about 15", and the height will be about 8". The original was 10m long, 6m wide and had a propeller with a 2.1m diameter. Power was provided by an Antoinette V16 engine.

The model will show interior detail of the boat's structure. I have chosen Costello boxwood for the wood structures within the model.

 

To get started / validate my drawings in some manner, I decided to create a mockup of the main pontoon and the two outrigger nacelles.

The shapes look good to me, so now I will be focusing on making the cross-sectional hoops that hold the shape of these three objects. There are 17 hoops to be make for the main pontoon and 5 for each nacelle. I plan on using a lamination method for the hoops - so making some thin strips of wood and a molds for the hoops will be the first tasks. While I'm working on the hoops, I will be thinking about how to make a jig that will keep them in place as the longitudinal stringers are attached to each.

 

 

[Jim Lad]

A fascinating project to build what looks like a truly terrifying piece of equipment, Greg.

 

John

[Greg Davis]

The hoops are going to be 1mm thick and 3mm wide. I made a mold for what would be the largest diameter hoop 1.25in. Unfortunately, this first hoop experiment was not successful - it broke taking it off the mold. Other than that it looks nice!

I had made this hoop using two approximately 0.5mm thick pieces of boxwood, but after bringing the thickness of the hoop back to 1mm it was to thin near one of the layer joints and fell apart there. I was worried that this might happen. Now I am sure that there should be at least three layers in the laminations to guard against this type of separation. This will require me to make up some material that is around 0.35mm thick. This will be a new challenge for me. In the past I was successful making sheets of 0.5mm cherry, so I'm hoping I can go a bit thinner with the Castello boxwood. 

[Greg Davis]

Two more tries and I think I have a method that will work. I was able to sand some C-boxwood down to 0.35mm with my Byrnes thickness sander. I then trimmed some strips off to use for the lamination. For the second try the wood was laid in a spiral - easiest to do, but I felt the inner bump was to extreme. I don't think I can reliably create a long bevel to get a smooth inner circle. So the third try is a three layer lamination were the seam from each layer is offset. I believe the result is worth the extra effort, especially considering there are less than 30 hoops to make - not much in comparison to framing a ship!

 

In this picture the hoop trials go from left to right: the broken two layer laminated 1st try, the inner bumped (at the top) 2nd try, and the three layer laminated 3rd try. The mold I used for the trials is above the hoops. I don't need to make a separate mold for each hoop as in some cases there are multiple hoops of the same diameter.

 

[Jim Lad]

Keep at it, Greg! You'll get there.

 

John

[KeithAug]

Fascinating model. I'm looking forward to seeing how it goes.

[Greg Davis]

Today I prepared a set of forms for the hoops. I made these starting with poplar dowels with 1.5" and 1.125" diameter that I picked up at the local Menards. 

Now it is time to make a lot of paper-thin wood to wrap around the forms.

[Greg Davis]

Today the thickness sander got quite the workout thinning stock down to 0.35mm. Good to have the material ready - hope that I made enough. It was just a bit sad to see how much waste there was between using the table saw to get about 1.5mm thick sheets and then to sand the sheets down to almost nothing. Going to try extra hard to get the hoops right on the first try!

[iMustBeCrazy]

5 minutes ago, Greg Davis said:

It was just a bit sad to see how much waste there was between using the table saw to get about 1.5mm thick sheets and then to sand the sheets down to almost nothing.

Working in Huon Pine makes me cry with every cut, every piece you can buy these days is salvaged.

 

You could try using plane shavings, a thick shaving would be about 0.2mm with very little wastage.

[Greg Davis]

30 minutes ago, iMustBeCrazy said:

Working in Huon Pine makes me cry with every cut, every piece you can buy these days is salvaged.

 

You could try using plane shavings, a thick shaving would be about 0.2mm with very little wastage.

I think that could very well be my backup plan - thanks!

[Greg Davis]

I have all of the hoop material for the main pontoon laid up on the formers. Three ply's for each. They were not too difficult to set up until the diameter dropped below 0.5" - the smallest one 0.30" was not fun.

I'll part off 3mm hoops on my lathe. Most I only need to cut one from but there are two pairs of hoops #4 & #7 and #5 & #6 that have the same diameter. For those I laid up wider strips of wood so that I can part two off each.

 

Still thinking about an assembly jig. This is what I am currently thinking of making:

There would be a 16 pieces of 1/8" hardboard cut to the above shape - one for each hoop. Each riser would be be made with the center of each hoop at the same height. The semi-circular cut out for each hoop's out diameter would top out 1.5mm lower than center to accommodate the 3mm side stringers. A notch would be cut at the bottom to accept the bottom (or top) stringer. To help keep the hoops stabilized thru the stringer installation, I will slice off a 3mm disk from each form to sit inside each hoop. This way I can press down / clamp the stringers without fear of breaking a hoop. A couple of tabs on each riser should keep the hoops / discs vertical.

 

An alternative would be to cut a more standard comb jig and keel support like those used for typical scratch built framed ships. For some (unknown) reason I'm more worried about getting all the necessary alignments to get the symmetrical / linear cigar shape.

 

Input certainly accepted!

 

 

 

[iMustBeCrazy]

1 hour ago, Greg Davis said:

I will slice off a 3mm disk from each form to sit inside each hoop.

I haven't fully thought this out but perhaps bore out these disks to take a shaft for alignment? Then your supports could support the shaft and be standardised, some fixed to a base some moveable to wherever you're working.

 

[Greg Davis]

 

13 hours ago, iMustBeCrazy said:

I haven't fully thought this out but perhaps bore out these disks to take a shaft for alignment? Then your supports could support the shaft and be standardised, some fixed to a base some moveable to wherever you're working.

 

Craig -

 

I thought about a shaft also but wasn't sure if it was needed. The more I think about it, the better the idea gets! The shaft can't be too big in diameter when it gets to the terminal ends or it just wouldn't go thru the smallest two disks. I don't think I could use more than an 1/8" diameter dowel. On its own the dowel wouldn't be stiff enough to be useful, but in conjunction with the supports it would likely do a good job. I could place rubber bands over the shaft to keep everything seated as well. A small diameter shaft should not be too difficult to cut into segments when it came time for removal of disks and shaft. I can bore the disk center holes via the tailstock on the lathe at the same time I'm parting the hoops / disks.

 

Thanks for bringing this option up!

 

Greg

[iMustBeCrazy]

3 hours ago, Greg Davis said:

The more I think about it

Greg, A few more thoughts,

 

No glue, just press fit. Or at worst a tiny dab of PVA on exposed surfaces that can be chiselled off later.

1/4" dowel stepping down at the ends. Perhaps in segments with couplers, slide the coupler along and the dowel is 'cut'. You could cut the disks with side cutters/wire cutters to remove them.

Some thin C.A. into the end grains before boring should give a smoother hole.

[Greg Davis]

42 minutes ago, iMustBeCrazy said:

Greg, A few more thoughts,

 

No glue, just press fit. Or at worst a tiny dab of PVA on exposed surfaces that can be chiselled off later.

1/4" dowel stepping down at the ends. Perhaps in segments with couplers, slide the coupler along and the dowel is 'cut'. You could cut the disks with side cutters/wire cutters to remove them.

Some thin C.A. into the end grains before boring should give a smoother hole.

Craig -

 

The step down idea is great, as is using some CA to make nicer holes! I was also thinking press fit so that the smaller disks could be slid inward where the pontoon diameter is greater for easy removal when it is time to disassemble. Once the stringers are in place there might not be enough room for cutters to get to the dowel. Instead I was envisioning using a jewelers saw to cut the dowel. I'll need to provide some protection to the stringers in the region the cutting is done, maybe some thin brass sheet slid under where the cuts are.

 

Thanks again,

 

Greg

[FlyingFish]

Great subject for a build - M. S-D seems to have been a remarkable chap. Bonkers even. An interesting project!

[Mirabell61]

On 2/22/2024 at 1:06 AM, Greg Davis said:

I have all of the hoop material for the main pontoon laid up on the formers. Three ply's for each. They were not too difficult to set up until the diameter dropped below 0.5" - the smallest one 0.30" was not fun.

I'll part off 3mm hoops on my lathe. Most I only need to cut one from but there are two pairs of hoops #4 & #7 and #5 & #6 that have the same diameter. For those I laid up wider strips of wood so that I can part two off each.

 

Still thinking about an assembly jig. This is what I am currently thinking of making:

There would be a 16 pieces of 1/8" hardboard cut to the above shape - one for each hoop. Each riser would be be made with the center of each hoop at the same height. The semi-circular cut out for each hoop's out diameter would top out 1.5mm lower than center to accommodate the 3mm side stringers. A notch would be cut at the bottom to accept the bottom (or top) stringer. To help keep the hoops stabilized thru the stringer installation, I will slice off a 3mm disk from each form to sit inside each hoop. This way I can press down / clamp the stringers without fear of breaking a hoop. A couple of tabs on each riser should keep the hoops / discs vertical.

 

An alternative would be to cut a more standard comb jig and keel support like those used for typical scratch built framed ships. For some (unknown) reason I'm more worried about getting all the necessary alignments to get the symmetrical / linear cigar shape.

 

Input certainly accepted!

 

 

 

An very interesting model Greg,

did this hyroplane ever lift off?

 

Nils

[Jim Lad]

Looks like you're making great progress on this unusual model.

 

John

[Greg Davis]

On 2/23/2024 at 11:44 AM, Mirabell61 said:

An very interesting model Greg,

did this hyroplane ever lift off?

 

Nils

Nils -

 

It wasn't designed for flight - it was a watercraft. In a couple of well regarded biographies and on some web sites there is a misrepresentation of the No18 hydroplane. It seems that in the early 1900'sthe term hydroplane had at least two meanings - the predominant being that of an airplane that could rise from water, like a float plane; the other, that of a boat that skims the water surface like a modern day hydroplane. I imagine that the Santos-Dumont biographers that have made the misrepresentation were so focused on his role in developing aircraft that they may not have even realized that No18 was a boat. Unfortunately, this kind of a mistake in the biographies makes me wonder a bit about other information that they have written / repeated about him! 

 

Greg

[Mirabell61]

Thanks Greg for your explaining words,

now its understood ....

 

Nils

[mtaylor]

Interesting on the descriptions, Craig.   Language, especially English isn't static, meaning change over time and sometime a word can have several definitions that are not compatable.  I think you're spot on with your take of the meaning.

[KeithAug]

On 2/8/2024 at 11:13 PM, Greg Davis said:

It was just a bit sad to see how much waste there was between using the table saw to get about 1.5mm thick sheets and then to sand the sheets down to almost nothing.

Yes - our hobby its incredibly wasteful isn't it. I console myself with the knowledge that in the main I am only wasting renewable materials.

[Roger Pellett]

Is it possible that “hydroplane” gets confused with “hydrofoil”?  Earlier pictures posted show submerged wing like lifting surfaces.

 

Roger

[Greg Davis]

11 hours ago, Roger Pellett said:

Is it possible that “hydroplane” gets confused with “hydrofoil”?  Earlier pictures posted show submerged wing like lifting surfaces.

 

Roger

That certainly could be the case - it might even be a better description for this craft than hydroplane!

[Denideul]

I found out  a document (in french) explaining that N18 was originaly the first part of a hydroplane that should have been completed with a wing.

But the wing manufacturer named "Voisin" never delivered the wing.

"No. 18
No. 18 was to be a hydroplane of
speed consisting of three floats built by
Lachambre joined by a metal frame
carrying engine and sails. The sail, which was to
coming from "Voisin", was never delivered.
After tests on the Seine river without an engine at the end
of the summer, Santos-Dumont installed on No. 18
the 50 hp V8 Antoinette engine then in September the
100 hp V16 engine which comes from No. 17, before
flow with her into the Seine river and escaped from drowning

. On October 17, 1907, he returned the machine to
condition for a photo shoot.

If it can help ...

 

machines_volantes_santos-dumont.pdf

Edited March 2 by Denideul

[Greg Davis]

On 3/2/2024 at 2:20 PM, Denideul said:

found out  a document (in french) explaining that N18 was originaly the first part of a hydroplane that should have been completed with a wing.

But the wing manufacturer named "Voisin" never delivered the wing.

Thank you for providing this link. I am grateful for your interest in the craft and willingness to share. However, I am not sure of the information presented in the document - I really wish that there had been references included. My comments below are not meant to discredit, but to critically question the translation (I don't read French either!) in light of other information that I have gathered. 

 

I have not run across other information noting any collaboration with Voison, I believe that they were actually competitors. As translations can sometimes go astray, I wonder if some comparison was being made to Voison's 1905 glider that was (like the No 18 during testing) pulled by a racing motor boat on the Seine. 

 

I am still looking for additional sources that would validate 'three floats built by Lachambre'. My impression, from the sources that I have read, imply that work on his crafts were done by a group of builders / mechanics that were long-term hires by Santos-Dumont.

There are not many contemporary written in English about the No18, but here are a couple printed in Scientific American from October 1907. In neither case is the No 18 portrayed as a plane; it is clearly portrayed as a boat. The 'driver' is described as helmsman - a term typically used for the person controlling a ship or boat. The hydrofoils are referred to as wings - perhaps that is what wings in the translation refer to.

I certainly will not forget what you have shared and should I find evidence in support of the translation I will immediately pass it on.

 

Thanks again,

 

Greg 

 

 

[Greg Davis]

Finally got up the courage to part off all of the pontoon hoops. 15 out of 16 were successful. Hoop 16, the one with the smallest diameter, was a fail. It turned out that I had not been able to lay up the hoop material tight enough to form the solid hoop. I will need to remake that one using a different technique. I may try thin shavings as Craig suggested earlier. I drilled 1/4" holes in the center blanks for hoops 2 - 14. Numbers 1 and 15 have 1/8" holes, but I think I may be able to open them to 1/4" as well.

Now that I have these hoops made, I can use their outside diameters to begin construction of the pontoon building jig. 

[Greg Davis]

Today I've made a good start on the building jig. I made up supports for hoops 1 - 15; I'll deal with one for hoop 16 after it is remade. The supports are made from 1/8" hardboard and are approximately 2" square. First I had made a number of 2" x 4" pieces with a center line along the 4" dimension. I used the midpoint of this line to mark the center of the pontoons axis. I drew semi-circles to match the outside diameters of the hoops using this mark - Two per blank. They were cut in half and then the semicircles were cut on a scroll saw. A little filing and the hoops fit in nicely. Finally the height of the supports were cut to 1 15/16" (measured from the bottom) so that the side stringers can rest on the supports when they are being attached. I need to mill a notch in the bottom of each semi-circle so that the top / bottom stringer will be accommodated for as the pontoon sits in the jig. I will also add a few tabs to insure the hoops stand perpendicular to the building board.

 

[Greg Davis]

Here is a picture showing some progress on the building board / jig.

[Greg Davis]

One more pic for today - a test fit of hoops in the jig. Here 13 of the 16 hoops have been slipped onto a 1/4" dowel. I'll be holding the dowel down using rubber bands at each hoop location when work is being done. As expected, tabs and/or another stabilization method will be necessary to keep the hoops squared to the jig.