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

[Jim Lad]

Nice to see that this interesting project is still going ahead.

 

John

[Greg Davis]

19 hours ago, Jim Lad said:

Nice to see that this interesting project is still going ahead.

 

John

John -

 

Thanks for your interest! It will certainly get done, sometimes I just have a problem with jumping around on multiple projects at the same time. Some people call it multitasking, but it more likely lack of focus at times. I had built the Santos-Dumont 14bis (because it looked really interesting) as a winter break from milling wood and sanding frames for my L' Invention model. That was not to take a long time, but then I came upon pictures of the No. 18 Hydroplane and making a model of this machine has moved up high on the to do list. I believe that now I am going to be making fairly regular progress on the hydroplane model. It seems that I've figured out how to construct the pontoon and nacelles. I'm now thinking about how to do the metal work that connects these three parts. The metal work for the engine mount looks to be straightforward. Making a nice steering wheel will take some doing and I have a pretty good conjecture on how the steering would have been rigged. That then leaves the last big piece of work - the V16 Antoinette engine. I have two of the Model Airways Antoinette V8 engine kits that I plan to bash into a V16. From what I have been able to uncover, this is pretty much how the Antoinette V16 actually came about. So this is the basic plan of attack on the hydroplane and then back to L' Invention big time.

 

Greg

 

P.S. I may also be trying to finish a few other models that were started in the distant past concurrent with this project ... I hope I don't start anything else ... Is there a part of the MSW forum that helps people keep the number of projects manageable?  

[Greg Davis]

I've remade hoop No. 16 to my satisfaction. I tried making shavings, but I didn't like the outcome too much. Then I took some of the 0.3mm material I had made previously and thinned it out even more with a spindle sander. I probably got it well below 0.2mm. At this thinness I was successful wrapping it in layers around the form. I also enlarged the holes in the forms that had been 1/8" to 1/4" - now all 16 hoops (with forms) fit nicely on the 1/4" diameter dowel. Here is a picture of hoops 15 and 16 sitting on the pontoon jig.

Just a little more work on the jig and I can start attaching the longitudinal stringers that hold all of the hoops together.

 

 

[Greg Davis]

Jig is done and the main pontoon is ready for the addition of longitudinal stringers. I added a bunch of hooks that let me place rubber bands over the axial dowel. This keeps the hoops snugly in place / aligned on the jig. I've also waxed the top of each support where the stringers will be attached so that there is less of a chance of getting the structure stuck to the supports. I plan on installing the side stringers first. Because of how the supports were fashioned the stringers will lie on top of each support when being attached to the hoops. Once they are in place, the rubber bands will be removed and the pontoon will be turned 90 degrees so that the top and bottom stringers can be added. Slots have been milled into the bottom of the supports to allow for the stringers to slot into when the pontoon is turned. 

Time to mill some wood!

[Jim Lad]

A very practical setup for fitting the stringers, Greg.

 

John

[Greg Davis]

I've milled the 4 longitudinal stringers. The top and bottom stringers are 2mm x 3mm in cross-section and will be positioned so that a 2mm side meets the hoops. The side stringers, which are being attached first, are 1.5mm x 3mm with a 3mm side joining with the hoops. 

[AON]

do the extreme ends need to be tapered like staves on a barrel?

[iMustBeCrazy]

1 hour ago, AON said:

do the extreme ends need to be tapered like staves on a barrel?

It looks like they end at a small disk.

 

[AON]

I imagined more of them.

[Greg Davis]

13 hours ago, AON said:

do the extreme ends need to be tapered like staves on a barrel?

I'm not sure how the extreme ends of the pontoons and nacelles were finished. I think that in the picture that Craig shows above, the four stringers are being held in position by an external band. I can't tell if the band / hoop is wood or metal. I also have wondered if this fastener is temporary or if it is permanent. Eventually I concluded that it is temporary. When looking at a pictures of the finished pontoon it doesn't appear as a bump under the covering. Clearly, the finished pontoon comes to a fine pointed end; one that is strong enough to support a metal collar used for rigging the boat. It is doubtful to me that the stringers would be shaped to such a point, but perhaps there is additional wood attached / interfaced with the stringers, such as a solid wooden cone. Currently, I have been planning on introducing something along these lines for the ends of the pontoon / nacelles. I know that it would be purely conjectural in nature and if more historical information was located it could be modified to match without too much difficulty. 

Related, here's a picture of the pontoon construction before the band was connected to the structure. Henrique Lins de Barros shared this picture with me, it is part of his personal collection and is one that I have not seen using internet searches. If I interpret Alan's last comment correctly, I agree that this is a machine with a bit if a fragile structure! But Santos-Dumont had a lot of experience building skeletal frames for his machines that were minimal yet strong enough for the task at hand. I also imagine that the covering together with the inflation of such made a pretty strong machine and helped define the pontoons envelope. On the other hand, the wooden structure needed to be strong enough to hold the engine, propeller, etc. in place! 

 

[iMustBeCrazy]

This enlargement might help.

 

SD 18-cleargc.zip

[Greg Davis]

2 hours ago, iMustBeCrazy said:

This enlargement might help.

 

SD 18-cleargc.zip 13.58 MB · 3 downloads

Wow - this is such a great picture! Thank you so much for sharing!

 

Greg

[druxey]

Impressive photo!

[iMustBeCrazy]

Another enlargement:

 

Santos_Dumont_N-18g.zip

 

It looks like the front foil (and I think the back) had suspension:

 

[Greg Davis]

17 hours ago, iMustBeCrazy said:

Another enlargement:

 

Santos_Dumont_N-18g.zip 4.81 MB · 2 downloads

 

It looks like the front foil (and I think the back) had suspension:

 

This is so helpful!

 

Yes, there is suspension for both hydrofoils. I sometimes have an orientation problem on how they work and need to remind myself that it is the top brackets that are connected to the hydrofoil support post, and this is what moves to stretch the bungie cord suspension. 

[Greg Davis]

I've attached all four stringers to the pontoon hoops and released the whole structure from the jig.

Before I remove the solid discs inside the hoops I plan to drill holes for 'bolts' that connect the stringers and hoop, as well as for the support cross-wires. I suspect the cross-wires are actually bicycle spokes so that they could be tensioned.

[iMustBeCrazy]

2 hours ago, Greg Davis said:

I suspect the cross-wires are actually bicycle spokes so that they could be tensioned.

I suspect all the wires came off a roll of bicycle spoke wire, the hoops were essentially wooden bicycle rims and the tubing was bicycle frame tubing either flattened at the ends or rolled into an oval for streamlining.

 

 

 

[Greg Davis]

Today I cut out the alignment dowel and the hoop forms. Removing the solid disks required making three or four radial cuts from the dowel hole to the hoop. Once the cuts were made, I cut remove each sector of the disc in turn. I think that there were only two disks that easily came out whole. So here is where the project is now:

Next will be to add some metal fasteners thru the stringers and into the hoops. The wire cross braces will then follow. Holes have been drilled for these details already.

Edited May 6 by Greg Davis

[Greg Davis]

Today I finished adding the metal fasteners. I decided to use 22 gauge copper for them. I also started adding the cross braces; they are being made from 0.015" piano wire.

 

[Jim Lad]

Looks great, Greg.

 

John

[KeithAug]

I reminds me of my youth and balsa model airplane kits. All very interesting Greg.

[Greg Davis]

All of the cross braces are in place. A nose cone has been shaped as well - I may try to make this a little more pointed later.

It's now a little later. After looking more at the above picture, I really started to feel the nose was too blunt. So with a sanding stick back in my hand, I've tried to make the transition more smooth. I'm good with this (for now)!

[iMustBeCrazy]

9 minutes ago, Greg Davis said:

I'm good with this (for now)!

I think it's fine, it looks like the pointy bit is a metal cap with flanges for the wires.

 

Overall I think your model looks a little too good, better than the original.

[Reverend Colonel]

Great idea for a model. Can't wait to watch it continue to take shape. It looks wonderful and I really enjoyed seeing how you approached and executed the first portion of this model. Keep up the great work. 

 

Humbly, J

[KeithAug]

On 5/9/2024 at 12:04 AM, iMustBeCrazy said:

Overall I think your model looks a little too good, better than the original.

As is the case with very many MSW models. Fortunately age is gradually deskilling many of us. Soon authentic representations will become more common.

[Greg Davis]

For the last couple of months I had spent a lot of time working on an Amati kit of a Xebec that I had started back in 2015 - I finished it today and got right back into this build. 

 

I've decided to work on the nacelles next. So I've just bent some wet wood around a few of the hoop formers that I had made for the nacelles. The wood strips are 15mm wide, so I hope to be able to cut off two 3mm hoops from each - one for each nacelle. This should help keep the nacelles the same size (as well as reduce the time needed to make the hoops).

Two more forms to wrap up. Form #4 will not be a problem, it is the same size as #1; but #5 is going to be a challenge, this hoop will have an inner diameter of 0.25". Later, like for the main pontoon, I will build a jig for attaching stringers to the nacelle hoops.

[Jim Lad]

You make it look easy, Greg.

 

John

[Greg Davis]

It turns out that laying up the 15mm wide strips is a bit more challenging than the narrower strips I used for the main pontoon hoops. Nevertheless, all of the nacelle hoops are laid up. The 0.25 inner diameter hoop has 4 very thin strips, whereas the other 4 have been made with 3 layers. The smallest diameter one really took some patience - there were a couple of times I thought about laying up a pair of narrower strips for this one. But all is good now and it is time to go back to the lathe to turn the hoops to the required 1mm thickness before parting off the 10 hoops I need to proceed to the next step. I also hope I remember to drill center holes to pass an alignment dowel thru the parted off pieces!

 

[Jim Lad]

Looking good, Greg.

 

John

[Greg Davis]

Today, I got up the nerve to part off the nacelle hoops. The work appears to have been successful and they all thread onto a 1/4" alignment dowel. Next I will set up a jig to hold the hoops in place during the stringer attachment process.