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j ferguson · 13 November 2008, 07:15 AM

Joe,
After reviewing all of the above, I realized that I've been pitching something I wouldn't do myself if it was my plane.

There is a great advantage to having two main floats. It is very unlikely that they would both leak at the same time.

I''m also skeptical that you are going to get a big leak on landing that isn't a disaster in a lot of less pleasant ways than having the plane sink gently beneath the waves which is what the extra flotation is intended to prevent.

Accordingly, and if it was my plane, I would not have any additional flotation.

I would paint the aviation equivalent of plimsol lines on each float. If you can see the sides of the floats from the cockpit, then I would paint them on both the fuselage side and the outside of each float. Assuming the plane sits level (in roll) in the water, both sets of marks should agree. If not, there's a problem.

I can't believe you are ever going to drag this up on the beach. More likely it will either be moored, or sitting on its cart. So abrasion and rock damage seem unlikely.

Finally, I would do as one of our colleagues has suggested and build two sets of main floats.

A number of projects on the boat have been "faked" or mocked up with cheap plywood to check "proof of concept" with the idea of building the real thing with better materials and more care, once I was confident with the design. Once in a while, the mock-up wound up being the final project, dinghy cradle for example.

In your case, I would do my best on the first set of floats to make them usable but then introduce whatever refinements or innovations come to mind on the second set. I would also install the diaphragms shown on the Sopwith drawings.

As to problems with water, I remember a college room-mate who had been a "stewardess" on an Alaskan airline that flew Catalinas in the late fifties - they were serving locations in the Aleutians that didn't have airports and he was male despite the job title which he said was non-negotiable through some perverted sense of humor on the part of the operator.

He said that his principle job was to pump water out of the fuselage and floats before every flight - and there was a lot - mostly via missing rivets in the hull.

I don't think this is going to be a problem for you.

13 November 2008, 07:15 AM	#514 (permalink)
j ferguson Forum Ace Join Date: May 2006 Location: Intracoastal Waterway, USA Posts: 581	Sheepish Joe, After reviewing all of the above, I realized that I've been pitching something I wouldn't do myself if it was my plane. There is a great advantage to having two main floats. It is very unlikely that they would both leak at the same time. I''m also skeptical that you are going to get a big leak on landing that isn't a disaster in a lot of less pleasant ways than having the plane sink gently beneath the waves which is what the extra flotation is intended to prevent. Accordingly, and if it was my plane, I would not have any additional flotation. I would paint the aviation equivalent of plimsol lines on each float. If you can see the sides of the floats from the cockpit, then I would paint them on both the fuselage side and the outside of each float. Assuming the plane sits level (in roll) in the water, both sets of marks should agree. If not, there's a problem. I can't believe you are ever going to drag this up on the beach. More likely it will either be moored, or sitting on its cart. So abrasion and rock damage seem unlikely. Finally, I would do as one of our colleagues has suggested and build two sets of main floats. A number of projects on the boat have been "faked" or mocked up with cheap plywood to check "proof of concept" with the idea of building the real thing with better materials and more care, once I was confident with the design. Once in a while, the mock-up wound up being the final project, dinghy cradle for example. In your case, I would do my best on the first set of floats to make them usable but then introduce whatever refinements or innovations come to mind on the second set. I would also install the diaphragms shown on the Sopwith drawings. As to problems with water, I remember a college room-mate who had been a "stewardess" on an Alaskan airline that flew Catalinas in the late fifties - they were serving locations in the Aleutians that didn't have airports and he was male despite the job title which he said was non-negotiable through some perverted sense of humor on the part of the operator. He said that his principle job was to pump water out of the fuselage and floats before every flight - and there was a lot - mostly via missing rivets in the hull. I don't think this is going to be a problem for you.