J-3 Cub Rubber
Motor Pin and Modified Cross Members
Two pieces of 3/16" I.D. aluminum tubing were
cut to a 3/32" length and filed smooth. These were CA'd into the 3/32" balsa
side members for the rubber motor pin as shown below.
A proper length of 3/16" wooden dowel that serves
as the rubber motor pin slides into the aluminum inserts snugly as shown
below.
There was a construction set back today when it
was discovered that all of the top longeron cross members were in the line
of the rubber motor as a result of raising the rubber motor pin in the back
of the fuselage. The 3/32" cross members had to be cut out and some new
3/32" arches were made to replace the two rear cross members. The most
forward cross member was cut out and a piece of 3/32" square balsa was glued
across the bulkhead up from the top longeron about a 1/2" as shown below.
This is a proof view looking through the front
bulkhead opening and down through the center line of the fuselage. It shows
the clearance of the rubber motor with respect to the modified structural
cross members. The cross members that were cut out had the same shape as
the bottom cross members seen
below.....................................Tandy
