AUTHOR:DAVID GLADWIN
gap restored but the airflow onto the stabiliser
is guided by SMURFS, Side Mounted Unit
Root Fins.
All three of my Hawks have these aerodyna-
mic “fixes” so perhaps even at the Reynolds*
number of our models, they work!
Finally on the subject of aerodynamics it
might be worth raising two other points:
There are a number of different versions of
the beautiful Hawker Hunter now available,
some have the wing leading edge correct but
others follow the often published incorrect
leading edge extensions which were fitted
from the Mk4 onwards to reduce pitch up at
the stall. On the Hunter the LE extension has
a chord of 6 inches (or so) at its root, tapering
to 4 inches the tip. The LE extension does
NOT taper back to the original leading edge
as shown on so many drawings and reprodu-
ced on some models, but not, of course, on
photographs of the real jet.!
Secondly, one leading manufacturer, when
offering advice on dealing with a flameout,
suggest extending flaps to improve the
lift/drag ratio. This is not correct. If a flameout
is experienced such that RANGE to reach the
runway is a key factor the best L/D ratio, and
therefore range, is to keep flaps UP, optimi-
zing the L/D ratio, and fly at the best speed
for optimum range. That speed is difficult to
judge on a model but so is the best speed
with flaps out!
* Reynolds number reflects the ratio of the
object over which the air is flowing over or
through to the viscosity of the air. Models pro-
bably, almost certainly, will not reflect exactly
what is happening on the full size example
because, although we can scale the model,
we cannot scale the air. To give a simple
example, to reproduce the behaviour of a real
jet at 200 knots, with a model of say 1/10th
scale, we would need to put the model in a
wind tunnel generating 2000 knots, clearly
impossible but that’s the theory! At least
Reynold correctly forecast that bigger models
fly better!SERVO LEAD EXTENSIONSOn most models final fit out involves cable
extensions of various lengths and for many
years my own solution has been either to
plug together cables of various lengths or to
solder together cables to produce as near
exactly the required length. Soldering is both
time consuming and has the associated risk
of dry joints or fracture so the ideal solution is
to make cables of exactly the correct length
without the soldering.
Some years ago, I purchased a crimping tool,
cable and some plugs to make up tailor made
cables but did not have much success and
put the crimper aside, perhaps my problemPowerBox systems offer sets of parts for both male and female plugs and sockets.PowerBox premium wire is heat resistant to very high temperatures, virtually
flame resistant, ideal for installations near engines and tailpipes.Gladwin_Layout 1 07/03/18 11.58 Pagina 4