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

[Greg Davis]

8 hours ago, iMustBeCrazy said:

Greg, do you have any evidence of a rudder? I can see what may be a rudder in the middle of the rear foil in the early version and perhaps aft of the hull in the later.

If I'm right about the early version the entire foil must rotate to turn.

I don't think the wheel was used for steering at least in the early version, I think the lever on the right was. It's too big for a throttle lever and a lever was how he steered his aircraft.

I think the speed was controlled by 'blipping' the engine with a kill switch on top of the lever, this would be consistent with aircraft through WW1.

I believe that there is a small rudder in the middle of the rear foil. The first picture you have in your post had made me believe so, as well as pictures taken in SD's workshop where the rear hydrofoil is propped up in a way to keep the rudder from touching the ground. But perhaps most convincingly is the film showing the hydroplane being placed in the water at 54:15 in this video: 

 

 

 

 

Also notice that as the hydroplane is carried their doesn't appear to be rotational motion of the rear foil structure. This footage, together with the bracing geometry is what has prevented me from thinking the rear hydrofoil moved as a unit for steering. If the hydrofoil rotated the bracing wires (fore and aft) would need to change length - first and third drawings below. The other issue I can't rectify is that the lever on right - which based on Craig's wonderful enhancement - always is pictured at the same angle and has just one wire / cable leaving it (to the front). If the lever was to be used for steering, it could be pushed forward to pull back on the cable and steer to one side; however, there doesn't appear to be a mechanism to turn in the opposite direction. I did consider the possibility of a spring / bungie return, but again this goes against the bracing geometry questions I have. 

 

Craig's last picture, in some ways, increases the mystery - here it appears that the rudder post is rectangular and this makes me infer that the rudder could not turn independent of the hydrofoil.

 

Santos-Dumont was known for his simple / purpose only designs. It seems strange to me that our collective analysis of a potential steering mechanism is not providing an obvious and clear understanding.

 

Right now, I wonder about the possibility that there was not a steering mechanism at this point - simply a point and shoot set-up. Maybe it was only used when the hydroplane was towed and/or short test runs. Perhaps, the structure in behind SD in the later modified version of the hydroplane is a rudder box that made the boat steerable.

 

3 hours ago, druxey said:

This may sound bizarre, but in the first photo it appears that the seat and wheel, as well as the foil/rudder, is rotated. Was steering literally by the 'seat of the pants'?

Maybe it was worse that 'seat of the pants' and was not steering at all!

 

I do really appreciate the additional input / discussion!

 

Greg

 

[Greg Davis]

6 minutes ago, Keith Black said:

 Question, did the steering wheel actual steer or was it merely something to hang onto? 

It becomes more and more questionable to me daily!

 

[Keith Black]

 In the last photo of post #178 that Craig posted, the steering wheel tube appears to be just mounted to the seat board with no internal linksge out the forward end through the body to the rear or an external link for that matter. IMHO, the wheel was nothing more that something to hang on to  

[iMustBeCrazy]

As I see it at the moment:

 

The rear bracing convinces me that the foil does not rotate, therefore the 'rudder' is just a fin. 

The wheel is, in this version, non functional. Perhaps steering was done by leaning, that could work.

I still think the lever is massive for a throttle but at this stage I can conceive no other plausible function.

 

The video shows that the front foil is inadequate, probably the rear foil is too big and pops up first changing the angle on the front foil and preventing it from lifting leading to the changes aft.

[druxey]

"Curiouser and curiouser," said Alice!

[Keith Black]

 There is a thumb button on top of the lever.....starter button? Also, the steering wheel did turn because of the different wheel positions in the array of photos which is curious if all it's meant for is to hold onto? 

[iMustBeCrazy]

15 minutes ago, Keith Black said:

starter button?

Possibly, but realistically a bit early. I suspect it was to cut the spark to the engine, a kill switch, or probably a dead man switch, if he lets go (or falls off) the engine stops.

[Greg Davis]

10 minutes ago, Keith Black said:

 There is a thumb button on top of the lever.....starter button? Also, the steering wheel did turn because of the different wheel positions in the array of photos which is curious if all it's meant for is to hold onto? 

How they got the engine started is a great question - I have not seen a picture where the engine is running / propeller is spinning. I have seen a picture of how the SD 14bis was started:

Can't imagine getting something like this out on the water and stabilized enough to crank it. Also don't see how anyone would be willing to stand in front of this beast and turn the prop by hand - just imagine the problem of not getting trapped between the pontoon and a nacelle and all of the bracing wires! A quick Google search indicates that electric starters were not used (commonly) on planes until after WWI, and that Charles Kettering received the first US pattern for an electric car engine starter in 1911 - the starting being used on Cadillacs starting in 1912. So the chances of an electronic starter on this engine / hydroplane seems unlikely.

[KeithAug]

All very fascinating and enjoyable.