Committee:

Chairman - Jan Sime : Vice Chairman - Gordon Browne : Secretary -Caretaken by Jan Sime & Gordon Browne : Treasurer - Juanita Smith

Representatives:

HTL - Gordon Browne : Bill Voss - Dennis Bird : Postals - Jan Sime : F3B - Juanita Smith : F3J - Ian Sime : F3K - Juanita Smith/Shaun Mileson : F5J - Ivan Williams : 2 Meter/New Commers - Shaun Mileson : Slope - Izak Theron (Gauteng) Kevin Farr (WC) Rus Conradt (KZN) : Cross Country - Chris Adrian

Proficiency Badges: Juanita Smith

Calendar: Juanita Smith / Jan Sime & Gordon Browne


08 February 2012

2012 Postals Rules

The MGA Postal Thermal Contest
Revised for 2012
Introduction
The Postals competition is a typical “thermal duration” competition, which includes a restricted launch, defined flight task and scored landing. The Postals competition attempts to place everyone on an equal footing, but permits “home ground” advantage. This competition is considered the ideal development and promotion tool of the Model Gliding Association (MGA) Special Interest Group.
Climbing the Postals ladder is part of the fun, sliding down the ladder is a definite indication that you aren't doing enough flying.
Dates
  1. The contest consists of four rounds, flown any day in February, May, August and November, the four scores giving the total for the year.
  2. Each pilot may make only two attempts to record a score during each round. These may be on any day of the month but, once started (stopwatch running on first flight), the pilot is committed to completing that day’s score for one of the two submissions. Note that only one attempt per day is permitted.
  3. The highest score of the two attempts will be entered as the score for that round.
  4. The club score does not have to be recorded by pilots on the same day but must be scored from the same venue.

Flights
  1. Each entrant is entitled to FIVE (5) flights, which must be flown consecutively (allowing for legitimate reflights, or test flights which have to be nominated before launch)
  2. All FIVE (5) flights, count towards the pilot’s round score.
  3. Timing must always be performed by someone other than the pilot.

Launch
Launching may be by one of the following mechanisms:
  • electric winch (max available line from turnabout to ’chute 200 m)
  • bungee (200 m maximum stretched length)
  • 200 m hand tow, and two towmen
  • electric powered (the motor may only be used once for launching in a window of 30 seconds maximum and limited to a launch height of 200m - an onboard altitude limiting device must be used to achieve this)
Relaunch
  1. A re-launch may be called for if the line breaks, or the model pop’s off and “re-launch” is called before the parachute touches the ground. The flyer must then land and re-launch as quickly as possible – if the parachute touches the ground before re-launch is called, then the flight will count.
  2. A re-launch may be called by the pilot if the electric motor malfunctioned during the 30 seconds launch window.
  3. Once re-launch is called by the pilot, the flight is immediately cancelled even if the model continues to be flown.
  4. If any part comes off a model during launch or in flight, then the pilot may request a re-launch.

Models
  1. There is no restriction on the number of models an entrant may use in the course of the contest.
  2. The models will be classified into one of the following classes:
    • 2M = Model with a projected wingspan not exceeding 2000 mm and any number of controls
    • RES = Model with any wingspan but controls are limited to Rudder, Elevator and Spoiler
    • Open = Any other Model

Scoring
  1. Scoring is as for Task A in the (old) F3B rules, i.e. to a precise six minutes and a landing bonus of 100 if the model’s nose is within one meter of the spot
  2. The flight time is taken from the moment the model leaves the line/electric motor cuts out, until it comes to rest
  3. The landing bonus is measured after the model has come to rest and is reduced from 100 by 5 points for each meter beyond the spot (e.g. 95 points if the distance to the spot is from 1 meter to before 2 meters) down to 30 points or within 15 meters.
  4. The maximum score per flight is 460 points and 2300 points per round.
  5. A single table of results will be produced quarterly and will include details of the model class and pilot class.
  6. The club score shall consist of the top four individual scores posted for the club per round. Each pilot can only enter one score towards the club total per round.


Submission of Scores
Scores are to be sent to the Postals Coordinator & must include:
  • Club
  • Pilot name
  • Pilot Class (Senior, Junior, Rooky)
  • Model Class (2m, RES, Open, Electric)
  • Total score (only, no round by round times, etc.)
  • Model
  • Span
  • Launch method
  1. Please submit only the final scores of each round to the Postal Coordinator, Izak Theron — by e-mail to
    IT
  2. These scores should be in the last day of the designated month, or you will receive a zero score!
  3. Scores not specifying pilot class will assume “Senior”, and similarly scores not specifying model class will assume “Open” – there will be no retrospective changes permitted
  4. Scores not specifying the model, wingspan & launch method will be withheld from the table.

03 February 2012

F5J in 2012


F5J is a model glider competition class, soon to be approved by the International Federation of Aeronautics or FAI. In a very basic way it is a thermal duration competition with the gliders being launched by means of an electric motor.

Traditional thermal duration requires the glider to be towed to flying altitude by means of a 2 man tow team using a 150m line and pulley system. The problem with this method, (still used in competition) is that you require 2 willing helpers before enjoying a quick flight. This led to the use of an electric winch that allowed the pilot to fly on his or her own. The equipment in both cases is fairly costly and it was not long before someone popped an electric motor and a few NiCad batteries into a glider to enable easy launching.

Recent developments resulted in the availability of inexpensive and powerful electric motors and batteries. Electric thermal duration has become very affordable and has taken the model gliding world by storm. At first complex rules were used to penalise gliders with powerful brush-less motors in order to allow the brushed motors to compete. During the course of 2010 and 2011, a new set of rues were discussed and provisionally approved by FAI. In the new rules, any combination of airframe, motor or battery may be used as long as the following general specifications are not exceeded:
  •        Mass not greater than 5kg 
  •      Wing span not greater than 4m 
  •        Wing area not greater than 150dm²

Launch altitude is penalised by 0.5 points per meter up to 200m. For altitudes higher than 200m the penalty is 3 points per meter. Motor run time is limited to 30 seconds. Zooming after the motor cut point is dissuaded by the fact that the altimeter logs F5J competition altitude for a total of 40 seconds, after which the sky is the limit. This means that anyone can compete as long as the glider can reach a reasonable altitude within 30 seconds, and stay aloft for the required working time of 10 minutes.

Download the F5J Provisional Rules .

Choice of F5J gliders

Interested F5J pilots may wonder what airframe would be suitable. The first choice you need to make is on budget.

Up to R2000.00

I do not think that it would be possible to fly for much less than about 2k. Someone may prove me wrong but consider the cost of the limiting device at about R750.00 and you are nearly halfway there. On a budget you can haul out the 20 year old Gentle Lady and add a Park 450 – Park 480 size motor and you can be competitive. Many pilots are also dedicated scratch-builders and it might be an option if you have the time and patience.

Between R2000.00 and R3500.00

This would be an acceptable budget for beginners and experienced pilots that would just like to dip their toes into the F5J waters. There are a few very well designed ARF foamies for example the Parkzone Radian-Pro or Multiplex Cularis. Both of these foamies have 4 servo wings. You may also be able to get a moulded kit that can be fitted with the necessary hardware. The very successful 2m Tsotsi comes to mind. The Tsotsi is still produced by Evan Shaw and I believe that the Tsotsi MK. 2 will be available soon. Inexpensive airframes can be had in this price range from a number of suppliers. Google F5J glider or F5J sailplane and you might be surprised at the number available.

More than R3500.00

Most of the major competition sailplane manufacturers produce an “E” version of their F3J or F3B models. Check out SoaringUSA, or North East Sailplane Products to name a couple. Some of the “E” models from the likes of NAN will set you back $1600.00 or more, and that is without any electric components. These planes however are suitable for world class competition.

In conclusion, a wide variety of sailplanes will do very well. If you have an early F3J model you will find the fuselage space to be a bit more roomy than the latest competition models. This is good as it allows more space for the motor, ESC and LiPo batteries.

01 February 2012

New Electric Cross Country South African Record

On 28 DEC 2011, Piet Rheeders set a new South African Electric Cross Country record of 100,72km.

The flight started at 6.58am, approxametly 35 km south of Kenhard in Bushmanland, Northen Cape and ended at 8.33am (total flight time 1 hour 35min) near Keimoes on the Orange River.

The record was established using a 2.5 meter wing span Electric Glider, of his own design, called the Boesman 

The Boesman

Glide distances varied from 3km to 6km depending on conditions and trim, with one 7Km glide. (Average between 3 and 6min glide time). No thermal soaring was attempted during the glide times.  The average speed was 63 km/h with a maximum of 96.8 km/h.

GPS used during the attempt, showing details at the end of the flight.













Evan Shaw Launching the Boesman.
Evan Congratulating Piet at the end of the flight.

Ivan William & Piet in the back of the Bakkie.
Ivan was the official spotter, timer and helper with Evan doing the driving.

The Pilot hard at work during the flight.

Wingspan: 2.5 meters
Root cord: 230mm & Tip cord : 150mm
AR: 13to1
Wing area: 50 sqdm
Wing section: SD7003
Weight: With 2xTurnigy Nanotech 4500 Ma/h Batteries (3cell) connected in parallel -  2.55 KG
Wing Loading:  +/- 50 gm/sqdm
Electric Motor: Dualsky  XM3542CA-6, 450 Watt,  IC equivalent  .21 to .25
Estimated current draw during flight (average dynamic current – 25 amps)
ESC: Hobby Wing 60 amp
Prop: 13 X 7 Graupner folding CAM Electric
RC Tx:  Hitech 7 channel  PCM modulation
Functions used: Ruder, elevator, ailerons, flaps and motor control.