(Tension Leg Tripods)
What is going on here?
The mission: February 26, 1998 Eclipse in the Caribbean. How to get all my equipment there and in one piece. See www.Rifkin.com for more details, under the heading Black Sun Expedition.
I decide to take a Bogen Tripod. The airlines managed to bend it, even when it was fully disassembled. We set up on a beach at low tide, the salt water was not good for it. And it was not steady enough, even with nine kilograms of water hanging on it. On the next trip I needed something better.
Our viewing site for the Feb 98 Eclipse
My Eclipse Picture with Shake
Top Row, The Porter Turret Telescope
Front Row, Cardoni Sky Chair, Dyna-Pod I, Lego-Scope and Dyna-Pod II at Stellafane 1999
(Dyna-Pod II won an award)
A tripod gets its rigidity from strong heavy legs. I know from many years of sailing, that you can build light but rigid masts with pipe and cable. The rigidity comes from how much energy (Dyna) you can put in the cables, by tensioning them with turnbuckles.
The rigging of our sailboat
Stellafane 1998, Paul Valleli is selling pieces of carbon fiber pipe. This stuff is light and strong, just what I am looking for, but I canít get enough of it to build a standard tripod. No problem, I have had plans for a Tension based design for years that I have wanted to build. The design called for cables to hold it together and some parts that would be under very high bending forces. Using conventional materials it would have had to been very heavy to handle the forces. The result was Dyna-Pod I. The design was a success for weight and functionality, however, it scared the airlines, and they would not let me carry it on, and it would need a special case to take it as baggage. It was still too big to put in a small suitcase. So it was back to the drawing board and the junk pile for parts. The result was Dyna-Pod II. Since I didnít want to spend the money on anymore carbon fiber pipe, I changed the design, so that all rigid parts would only be under compressive forces. The new design can be assembled tall or short. It can be assembled with either all fiberglass pipes or a mix of fiberglass and Aluminum, and since I ran out of fiberglass and I had plenty of the aluminum, it is made with some Aluminum pipe, but can be changed back, if I ever get more fiberglass pipe. I also wanted a design that used less hardware, as stainless steel turnbuckles are very expensive. The new design only uses one turnbuckle as opposed to the three that Dyna-Pod I uses. Dyna-Pod II stores very small and once stored is nearly indestructible. It is also very resistant to the weather. It has stayed out for weeks in the tropical sun, salt air and rain without any sign of problems. It has also been through five trips through the Dallas Fort Worth airport (DFW) and one to Egypt, in my baggage with out a scratch. They were both built as one of a kind and are not for sale.
Weight 6.2 pounds or 2.8 Kilograms
Height at mounting plate
Unassembled size 48.25" x 5.25" x 2.25" or 122.55cm x 13.33cm x 5.7cm
Materials: Carbon Fiber pipe, Fiberglass pipe, Aluminum and Titanium plates, steel cable, and steel and Aluminum hardware.
Cost The cost of the Carbon Fiber pipe is unknown but considered very expensive, the remainder of the parts cost about $50 at the local hardware store (if your hardware store is in a mill town and carries lots of industrial parts).
Requires three turnbuckles to make it rigid. "Wedgeless" design. No special machined parts were required. Lighted legs for safety.
The Airlines say it is too long to carry on boad, so it is back to the drawing board to design something shorter.
Dyna-Pod I, Disassembled for travel
(For size reference, Marvin stands 11 inches from Pom-Pom to Toe)
Dyna-Pod I Mounting Plate, Cables and Turnbuckles
Weight 6.8 pounds or 3.1 Kilograms
Height at mount, High position 60"
Height at mount, Low position 32"
Unassembled size 25.25" x 3.25" x 2.5" or 64.14cm x 8.25cm x 6.35cm
Materials: Fiberglass pipe, Aluminum pipe, Stainless steel cable, top plate is stainless steel, bottom leg connector is Delrin and Nylon, with all stainless steel hardware.
Cost Fiberglass pipe $20, Aluminum pipe $10, Stainless steel for top and coupling $10, The remainder was $30 at a marine supply store.
And about 20 hours of cutting drilling, lath work, welding and crimping
Can be assembled short or tall. Advanced design requires only one turnbuckle to tension it. Totally weather proof. Disassembles very small, almost indestructible. All five sections of pipe are approximately the same length.
If I make any more, I have new ideas learned from making this one, and the next one will weigh half as much and go together in a quarter the time.Link to production model
Dyna-Pod II, Disassembled for travel
Dyna-Pod II Cables and Turnbuckle
Dyna-Pod II Mounting Head and Leg Connector
Weight- Very heavy
Height at mount- What size log do you use?
Unassembled size- a small bag.
This is the Robinson Caruso Model. Using the design of Dyna-Pod I and local materials, I designed a kit that would let me utilize locally available resources to make a heavy duty Dyna-Pod.
The name Dyna-Pod and all designs are copyright 1998 by Alan Rifkin.
Please contact me for permission to use any of my Copyright material.
See www.Rifkin.com for contact information.