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Alec Smyth - "flyer"
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Sub name: "flyer"
Designer: Alec Smyth
Builder: Alec Smyth
Description:
Introduction
This sub will be a "flyer", rather like Deep Flight. It will be built very
slightly buoyant and driven down dynamically, so in the case of power loss
it will rise slowly. The sub has no tankage, so weights and volumes must be
very accurate. For this reason, I have adopted an approach of building it
"from the inside out", starting with components rather than with the
pressure hull. This allows me to do the hull calculations using actual
component weights as opposed to estimates. The approach also defers
incurring a major cost until late in the project, and it allows for design
changes as new ideas inevitably come up along the way. Most importantly, it
allows me to know how much weight I can afford to put into the hull before
committing. For example, I recently reduced the planned hull thickness from
7/16" to 3/8" because I needed to save 200 lbs.
The operator will lie prone looking through a bow dome. In fact, the sub
will have a double dome. The main one is blown from 2 inch thick acrylic. A
180 degree, 2" cast dome would have been nice but was cost-prohibitive.
| Concept drawing. Note there is no stern fairing in the plan yet,
although there will be eventually. (as 18 Apr 2002)
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| The "before" condition of my garage. (as 18 Apr 2002)
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| The first thing I built were the aileron and ruddervator actuators. (as 18 Apr 2002)
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| Custom rolled cylinder, the starting point for the pressure hull. One of the main problems is that such a cylinder is not REALLY round until you make it so. In my case I machined the stiffeners until I could force them in using a system of chains and levers. This stretched the cylinder into roundness. At one end, the cylinder had a slight teardrop shape which obliged me to cut out a tapering slice along the seam and then re-weld. Getting round stiffeners into an oval cylinder is like putting square pegs in round holes, and took me about 2 months' work. (as 18 Apr 2002)
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| Assorted rings for stiffeners, and the stern endcap. (as 18 Apr 2002)
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| This is Greg Cottrell holding the 2" thick bow dome he made. (as 18 Apr 2002)
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| I motorized my rotary table, and added a 32" flat disc, so I could mill large round objects. Here I'm milling a right angle edge on the dome. The dome appears opaque because its covered with a protective layer of paper. (as 18 Apr 2002)
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| Using the rotary table to mill the hatch land. Because heat from welding the land to the hull would distort it, I welded it to a 4" cylindrical section, then milled the sealing surface, then welded the 4" cylinder to the main hull. (as 18 Apr 2002)
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Caption: A workbench-load of stainless inserts, most of which I made before
starting on the hull. The row at the back is 3 removeable bulkheads for
taking through-hulls. This is an idea borrowed from Phil Nuytten, so you can
reconfigure things by just making a new disc rather than drilling new holes
in the hull. Immediately in front of the 3 discs are the 3 seats that go
welded into the hull.
| A workbench-load of stainless inserts, most of which I made before starting on the hull. The row at the back is 3 removeable bulkheads for taking through-hulls. This is an idea borrowed from Phil Nuytten, so you can reconfigure things by just making a new disc rather than drilling new holes in the hull. Immediately in front of the 3 discs are the 3 seats that go welded into the hull. (as 18 Apr 2002)
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| Here is one of the removeable bulkheads, with electrical connectors installed. (as 18 Apr 2002)
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| Some of the through-hull seats distorted during welding. To true them, I came up with this tool. The little knob handle was over-optimistic, as in fact one had to exert considerable force. The cylindrical base is conical with a 30 second angle. I pound it into the inside of the hole with a mallet, then adjust radius and height against the springs to machine the seat back into a smooth surface. (as 18 Apr 2002)
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| Same tool in action. (as 18 Apr 2002)
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| Interior. The camera has set its exposure based on the low light inside, so the hatch land and everything else outside are just white glare. The holes in the stiffener webs were used for forcing the stiffeners into the hull, and will eventually carry tubes and wires. (as 18 Apr 2002)
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| This is a view of the stern from underneath, with the sub rotated in its cradle. The yellow object at center is a SCUBA second stage for pressurization of motors and actuators. The stainless piping is a pressurization line. (as 18 Apr 2002)
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| Three quarter stern view. (as 18 Apr 2002)
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| Outside. (as 18 Apr 2002)
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Page created by:
Ray Keefer