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

[Greg Davis]

46 minutes ago, druxey said:

It looks as if some modifications were carried out between the two photos.

 

- The steering column is shorter and more angled in photo 2.

- The hydrofoil mounts look to be in the same relationship to the wheel in both pics.

- Either the aft end has been shortened (unlikely) or the whole 'cockpit' moved aft about two feet.

 

Comments or criticism?

I don't think there was a prototype as much as the No 18 Hydroplane was a 'work in progress', it seems to have been the case that Santos-Dumont modified many of his creations as they were built and tested.

 

The top picture that Craig posted was taken earlier than the bottom picture. The top picture is a reflection of this photograph (Henrique Lins de Barros sent me copies of some original pictures of the boat):

At this time the engine had not been attached to the boat. The second picture was taken later when the engine was in place and the boat was essentially complete. A couple changes are noticeable between the two pictures, the covering of the pontoon has changes from one that has longitudinal stripes to being a solid color. Another, functional, change is that there is a lever in Santos-Dumont's right hand in the early picture - I have assumed this was to be a throttle; in the second picture the lever is missing and additional  controls are now connected to the steering wheel.

 

For me, it is hard to say if the steering column has been changed because the pictures are taken from different angles. The steering wheel looks to have similar height wrt his chest.  S-D's leg looks straighter in the second picture, but this could also be from moving the saddle back a bit without moving the platform.

 

Since my model is to have the engine, my work should better approximate the later photograph. 

 

It's hard for me to work this one out as I feel (without photographic evidence) the rear hydrofoil structure should mount at a hoop location as this would minimize the number of holes / bolts needed to hold the craft together and maximize its strength. If I follow this line of thought, I should attach to one of the last two hoops - the second to last may be a bit to forward, but the last one I have might be to far back. The other options would be to attach just to the stringers between the last two hoops and/or add another hoop between them for attachment purposes. I'm not really fond of those solutions because it ruins some of the symmetry in the model.

 

I really appreciate the feedback and advice that all of you are providing and I hope it will help lead me to a satisfactory solution to the rear hydrofoil and cockpit locations.

 

Thanks to all of you!

[iMustBeCrazy]

Looking at it this way I think the rear foil mounts to the same ring as the foot brace. The support for the steering column mounts to the next ring, the board extends from the end of the steering column to just aft of the seat, the foil is also wider than the earlier one. Greg, note the flag in the pic you posted, probably for signalling the tow boat.

Still guessing though.

 

[KeithAug]

Quite an exposed helmsman position. I hope his hat is tied on.

[Keith Black]

3 hours ago, KeithAug said:

I hope his hat is tied on.

 His hat.......I hope his mustache is tied on! 

[Greg Davis]

17 hours ago, iMustBeCrazy said:

Looking at it this way I think the rear foil mounts to the same ring as the foot brace. The support for the steering column mounts to the next ring, the board extends from the end of the steering column to just aft of the seat, the foil is also wider than the earlier one.

I think you noticed the key to what happened - I've stared at these pictures countless hours and never noticed the change in the platform location! I wonder if after some trials, SD found that the rear end was not staying down enough so the platform was moved back to provide additional leverage. 

 

I'm now planning going forward to leave / position the rear hydrofoil on the second to last hoop and keep the the platform in the pushed back location.

 

Thank you so much for sharing your observation.

 

Greg