AMA Plans Service Showcase XB-35 - 2009/12

December 2009 65
XB-35
A flying-wing heavy bomber from the 1940s
JACK NORTHROP designed the full-scale
XB-35, which was one of the first attempts at
an all-wing heavy bomber. It was powered by
four Pratt & Whitney R-4360 turbo
supercharged radial engines that spun threeand
four-blade propellers, including
contrarotating types.
Clark Calkins designed this 64.5-inchwingspan
model, using built up-balsa, light
plywood, and a symmetrical-airfoil wing that
is joined in the middle. Power is provided by
four Silver Streak brushed motors and a
seven-cell, 1500 mAh Ni-Cd battery.
The XB-35’s flying weight was 46 ounces
when the design was published, but it could be
flown at a lighter weight and more efficiently
with today’s power systems and Li-Poly
batteries.
Clark noted that the model was stable and
easy to control with the correct CG. The
symmetrical airfoil, combined with virtually
no dihedral, did require the aircraft to be
flown; it would not self-correct.
The landing gear worked best from a hard
surface. The XB-35 had good ground-handling
characteristics and was easy to land, with a
tendency to float.
This design was featured in a construction
article published in the July 1996 MA. AMA
members can access the magazine’s digital
archives on the Academy’s Web site to read
more about it.
The XB-35 is AMA Plans Service listing
814E, and it is available for $30 plus shipping
and handling. See page 167 or go to www.mo
delaircraft.org/plans.aspx for ordering
information. MA
AMA Plans Service Showcase
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