Guys,
On my L-4E I made a steel frame and covered it with fabric per the original and am having another frame welded up right now and the cost is astronomical. I thought there had to be a better way so I experimented with three prototypes.
The first I made using heavy stock paper soaked with glue and covered with ceconite
The 2nd method was glass cloth but was very labor intensive and the cone was too brittle.
Finally I made one using very thin aluminum. I joined the cone using a folded seam and attached the modified steel frame with fine steel wire soldered on the inside. The aluminum cone is then covered with fabric. The stiffness of the aluminum cone means you do not need the heavy welded steel frame and the steel frame at the mouth of the cone is simply wrapped and soldered.
At $100/hr for welders around here you are looking at a couple of hundred dollars to have a frame welded up vs about $5.00 worth of material to "roll your own" out of aluminum.
Here are photos of the fabrication of the aluminum cone that weighs in at five ounces. The other picture is of one of the welded frames covered with fabric I have used before.
On my L-4E I made a steel frame and covered it with fabric per the original and am having another frame welded up right now and the cost is astronomical. I thought there had to be a better way so I experimented with three prototypes.
The first I made using heavy stock paper soaked with glue and covered with ceconite
The 2nd method was glass cloth but was very labor intensive and the cone was too brittle.
Finally I made one using very thin aluminum. I joined the cone using a folded seam and attached the modified steel frame with fine steel wire soldered on the inside. The aluminum cone is then covered with fabric. The stiffness of the aluminum cone means you do not need the heavy welded steel frame and the steel frame at the mouth of the cone is simply wrapped and soldered.
At $100/hr for welders around here you are looking at a couple of hundred dollars to have a frame welded up vs about $5.00 worth of material to "roll your own" out of aluminum.
Here are photos of the fabrication of the aluminum cone that weighs in at five ounces. The other picture is of one of the welded frames covered with fabric I have used before.
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