Speed 400
Cloudster Project
The plan pattern for the
Cloudster's firewall is shown below. The top and bottom portions are shown
cut out for 1/8" planking to extend to the front face of the firewall.
However, I prefer that the cowl butt up against an all plywood firewall so I
filled in the cut outs as shown below.
The firewall was cut out of
3/32" plywood and bonded to the front face of the fuselage main frame as
shown below. A wooden ruler was run through the two front side members of
the fuselage frame and two heavy steel squares were placed on either side of
the ruler to form a type of press while the aliphatic glue dried.
The picture below shows the
finished firewall with lightening holes bonded to the front face of the
fuselage main frame.
The picture below shows the
hand made Speed 400 motor mount secured to the firewall with four 2-56 cap
screws. Notice that the motor mount rear mounting ring will have to be
trimmed down about an 1/8" across the top to permit the cowl to fit up to
the firewall.
The Speed 400 motor,
spinner/adapter, and tail assembly were attached to the fuselage main frame
as shown below. The total weight at this point is 139 grams (4.9 oz).
A 1/16" piano wire was run
through to the top longerons and adjusted to balance point as shown below
for a CG status check. The balance point is 3/16" forward of the desired CG,
which is a good indication the model can be balanced without ballast
weight.........................Tandy
