continued
from page 1,
There
were a number of relatively unconventional
features on the Arrow, and aerodynamically the
CF-105, was, I believe, a considerable advancement
over contemporary aircraft. The Arrow program
was a very ambitious project for A. V. Roe and
for the RCAF, but seemingly well within reach
and completely attainable. Some of the design
features are worth mentioning, as detailed in
the following descriptions.
Design Features
The crew consisted of a pilot and a radar operator.
The advantage of a two-seat airplane as compared
to a single-seat airplane lies in the complexity
of the fire control system, even though the system
was intended to be entirely automatic.
The choice of two engines was a combination of
circumstances, with the main advantage being reduced
attrition. Perhaps the main factor, however,
was the very large weapons package required as
payload and the large amount of fuel required to
meet the range requirements. In the early design
of the airplane, the range requirements pretty
well sized the airplane, and at that time there
was just no single engine large enough to
provide the required power. The Arrow Mk.
I was powered by two Pratt and Whitney J75-P3
engines, which produced 18,500 lbs. of thrust at
sea level, with afterburner.
Delta Wing
The choice of a delta wing design versus a straight
or sweptback wing was, I believe, a compromise
to achieve structural and aeroelastic efficiency
with a very thin wing and at the same time to achieve
the large internal fuel capacity required for the
specified range. The structural advantages of the
delta design made achievement of this thin wing
section possible. (CF-105 thickness/chord radio
was 3.5%; CF100 Mk. 1 was 10%).
Some characteristics of a delta wing include:
No stall- There is no well-defined stall for
a tailless delta and this is perhaps the outstanding
feature. It permits flying the airplane to much
lower speeds compared to straight or sweptback
wings. Minimum speed is usually determined by sink
rate and/or minimum control.
Ground effect- Since ground effect is a function
of chord length, not wing span, the effect with
a delta wing can be very pronounced. This simplifies
the flare and landing problem. Landing the CF-105
was quite straightforward.
Light wing loading- CF-105 wing area was 1,225
sq. ft., and at normal combat weight, wing loading
was approximately 50 lbs. per sq. ft. Good
manoeuvrability at high altitude, high speed,
and also structurally strong.
