Since the Sun N Fun run I've been working on a major redesign of the ballast tank mechanism which goes in my 1/96 scale boats. I could not get it to blow in College Station and the servo seal has leaked repeatedly. So the time has come to replace the head and handle on my trusty D&E Miniatures axe.
After some disassembly, I found the tank would not blow because the Propel tank's internal discharge tube was plugged. The external fitting was removed and silver soldered closed. A new brass barbed fitting was installed on the end and silver soldered.
Cracks in the Lexan were also discovered around several screw holes so I purchased a new 3" Lexan tube from Small Parts, Inc. They sell Lexan tubes up to 3" od in 24" lengths. This is great because most other places you have to purchase an 8' minimum. Unfortunately, 3" is the largest diameter they carry.
Borrowing heavily from Gail Phillip's modification of his original D&E WTC-3.5, I sketched out the modifications I wanted. With Gail's assistance we turned a new 3" bulkhead master from which I created a mold. Four new bulkheads were cast and I headed back to Gail's where we turned the o-ring grooves on his lathe. I spent the better part of last Saturday marking and drilling holes in the cylinder to mount the bulkheads and tank. I also took the opportunity to lengthen the ballast tank by 3/4" in order to increase the reserve bouyancy for my LA model.
The blow/vent servo has long been a source of leaks so I decided to mount a mini servo on its side in the forward compartment over the battery and employ a radial shaft to activate the vent and blow mechanisms mounted on the after ballast tank bulkhead. The radial motion through the seal should greatly increase the watertight integrity. The diameter of the pass-through tube between the bulkheads was also enlarged slightly to allow the passage of the additional servo lead to the aft compartment along with the battery and speed control leads.
The result should be a much more efficient system, leak free, and maintainable in the field. Pictures will follow as things come together.
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After some disassembly, I found the tank would not blow because the Propel tank's internal discharge tube was plugged. The external fitting was removed and silver soldered closed. A new brass barbed fitting was installed on the end and silver soldered.
Cracks in the Lexan were also discovered around several screw holes so I purchased a new 3" Lexan tube from Small Parts, Inc. They sell Lexan tubes up to 3" od in 24" lengths. This is great because most other places you have to purchase an 8' minimum. Unfortunately, 3" is the largest diameter they carry.
Borrowing heavily from Gail Phillip's modification of his original D&E WTC-3.5, I sketched out the modifications I wanted. With Gail's assistance we turned a new 3" bulkhead master from which I created a mold. Four new bulkheads were cast and I headed back to Gail's where we turned the o-ring grooves on his lathe. I spent the better part of last Saturday marking and drilling holes in the cylinder to mount the bulkheads and tank. I also took the opportunity to lengthen the ballast tank by 3/4" in order to increase the reserve bouyancy for my LA model.
The blow/vent servo has long been a source of leaks so I decided to mount a mini servo on its side in the forward compartment over the battery and employ a radial shaft to activate the vent and blow mechanisms mounted on the after ballast tank bulkhead. The radial motion through the seal should greatly increase the watertight integrity. The diameter of the pass-through tube between the bulkheads was also enlarged slightly to allow the passage of the additional servo lead to the aft compartment along with the battery and speed control leads.
The result should be a much more efficient system, leak free, and maintainable in the field. Pictures will follow as things come together.
