THE HISTORY OF V.A.R.M.S The Annual Diary 1990 - 2009

58
2000 - 01
The Committee
President Des Bayliss/Max Haysom Secretary Ian Slack
Treasurer Richard Weil Editor Colin Smith
Contest Director Mark Withers Ordinary Member Martin Hopper
*Co-opted Members: Ordinary Member Jim Robertson
*Registrar Geoff Moore Sites Liaison Max Haysom
July 2000 - A.G.M. saw Peter Cossins awarded Life Membership of VARMS
Max Haysom awarded "Clubman of the Year".
... and James Robertson took his usual place on Committee for the 15th consecutive year since his
initial co-opting as co-ordinator of the "VARMS Expo" in 1986.
July 2000 - VARMS members/Australian team (Gerry Carter, Alan Mayhew and Carl Strautins,
with Rod Watkins as Team Manager ) compete in the F3J World Championships at Corfu in Greece
(see contests for results).
August 2000 - Max Haysom assumes the mantle of President for the remainder of the term as a
replacement for Des Bayliss who left the Melbourne area and moved to Cobden in October. ... and
Ian Slack takes over the vacated position of Training Officer to continue the Glider training sessions
on a fortnightly basis.
August 2000 Aspectivity 325 reflected the following article on a very discussable topic:
Ian Pullar placed a list of questions on the SFRC (Slow Flight Radio Control) email chat group
regarding "T vs V vs Conventional Tails". The following response (reproduced with permission)
was supplied by Don Stackhouse of DJ Aerotech, makers of a number of fine models including the
Monarch H.L. Glider.
The question - "Would be interested in hearing of dis/advantages of T, V & Conventional tails.
Have heard various theories but am confident there is a wealth of experience in SFRC group to
confirm or kill some of these.
The response(s):-
Regarding your questions/comments:
(a) Experience with outdoor craft indicates Convention to be more stable though V's keep
themselves safer when landing in grass ??
If the tail is properly designed, there should be no significant difference in the handling and
control authority of an equivalent V, T or Conventional tail. There are several different design
criteria involved that do conflict with each other a little bit, leading to some very subtle differences
in typical applications, but if there's a significant difference, that's a strong indication that
somebody didn't design the tails to be truly equivalent (more on that in a moment).
V-tails on models do seem to have the best track record in avoiding damage during typical
landing mishaps. That's one of the chief reasons I use them so often in my designs. Conventional
tails tend to drag the tips of the stabilizer through the grass (or carpet for indoor models), and T-
tails tend to impose high bending moments on the tail boom because of the high-mounted mass of
the stabilizer on top of the fin.
(b) Rule of thumb I heard was to measure the width and height of conventional tail, then make a V
tail that high and that wide ??
This is one explanation of the "Projected Area Method". That particular "rule of thumb" is
probably the single biggest culprit behind the myth of V-tails having poor stability. This widely
known (I've even seen it in college-level aero engineering textbooks written by folks who should
have known better), but DEAD WRONG method results in a V-tail that is WAY TOO SMALL.
All other things being equal, the closest thing to a rule of thumb that works well in most
applications is to make the equivalent T, V or conventional tail have the same TOTAL area. That's
right, add the area of the fin + rudder and the stab + elevator together, divide by two, and the
result is the area for each of the two panels of your V-tail.
The dihedral angle for the V-tail is a bit more complicated. This angle is what decides how