Tuesday, August 28, 2007

Wednesday, August 22, 2007

The Model Aerobatic South African Team to participate in the World Championship in Argentina -- Scott Crescent

In this first article, I would like to introduce the selected members to represent South Africa at the world champs to be held in Argentina and give a brief overview of how they were selected.

Team Manager: Nico Erasmus

Pedigree: Nico aged 54, started his devotion to the radio controlled craze at the age of 16. Started flying aerobatics about twelve years ago and has won numerous competitions in Sportsman, Advanced classes. He is currently flying in the Expert class. He’s greatest achievement is becoming the S.A Masters Champion in the advanced class in 2006.

Nico was selected by the team members as Team Manager, he will organize all aspects of the coastal practices, promotion campaigns, air show and sponsorship requests and will be the “Public Relations Officer” of the South African Team whilst in Argentina. The World Champs runs from the 10/11/07 and ends on the 18/11/07.

The team selection was based on three qualifying competitions: Nationals 2006, Masters 2006 and the Nationals 2007.

The top two ranked pilots indicated very early on that they would not be interested in team participation therefore opening the door for the upcoming pilots in the F3a Class.

1st Team Member: Marc Wolffe
2006-2007 F3A team ranking: 3
Region: Western Cape
Age: 42

Pedigree: Marc started flying at the age of ten, won the Junior Thermal Championships (gliders) in 1979. 1980 started flying power aircraft for the first time, in 1981 started his aerobatic career and won his first Provincial Championships in the F3A class in 1987, he has been crowned National Fun Fly Champ five times and seven times winner of the Western Province Scale Championship, four times Border F3A champion and two times Eastern Province F3A Champion.

Goal: Marc has bought Marcello Columbo’s Genises and plans to do well at the world champs.

2nd F3A team member: Ian Wentzel
2006-2007 F3A Team Ranking: 4th
Region: North West
Age: 34

Ian started flying radio controlled gliders at the age of ten and power planes at the age of 14, this modest aeromodellar started flying aerobatics in 1998 and advanced to the F3A class in one year, he was also the National Champion in the Expert class the same year.

Goal: Would like to get some international exposure and up his standard of flying.

3rd F3A team member: Carel Germishuys
2006-2007 F3A Team Ranking: 5th
: Gauteng
Age: 36

Pedigree: Mr. Aviator, Carel is a former Military aviator and now a SAA pilot. He started flying model aeroplanes in 1987 and started flying aerobatics in 1997. He has won numerous provincial competitions in all classes. Carel enjoys wide variety of model aviation and actively takes part in Large-Scale and Electric disciplines.

Carel was team manager for the team that took part in 2005 and this time round will be flying.

The other members elected Carel Team Captain.

Goal: Would like too see what ranking he can achieve amongst the best of the best.

Friday, August 17, 2007

Antennas and batteries -- Piet le Roux

I am glad to see a lot of technical information and tips in the July issue of SAMAA News. There are however some points where I beg to differ and some points that I would like to ad.

Mr Armitage is a keen advocate of an "antenna outside" installation. I think that a secure antenna installation is important to secure reliability in the long run. To accomplish this you must place it inside the plane. If you bend any type of wire enough times it will break. A wire on the outside is vulnerable to damage and is constantly oscillating in the slipstream. If only a few of its wire strands break, it will cause the same type of noise as vibrating metal to metal contact points. You will be unaware of the deterioration of your antenna because it happens inside the insulation. Most RC pilots never replace their receiver antennas and install it from plane to plane on the outside. An accident waiting to happen! I normally use the inner of a thin cell-phone type coax as antenna wire. When I assemble the plane, depending on its size, I glue the end of the antenna under the vertical fin and keep all the battery and servo leads to one side of the fuselage and route my antenna on the opposite side, securing it with glue and cable ties. On the receiver I leave a short "pig tail" that I solder to the antenna and cover with heat-shrink after I have secured the antenna and receiver. Remember the total length of your antenna must be the same as the original (99cm for JR equipment). Wires and rods running along side the antenna will have little effect on its performance as long as they are not near a resonant length, for 35MHz this is about 2 meters. If it happens that you experience noise from you servo leads use ferrite filters on the leads. Just running the lead thru a ferrite ring will not do much; get the clip-on type that enables you to coil the lead around the ferrite.

If you have a portable transistor radio that covers the shortwave bands, you can utilize it as a noise detector. Tune it to a clear portion of the highest short wave frequency, some goes up to 22MHZ (13 meter band). The level of electrical noise decreases when you increase the frequency, so don't worry that your receiver is receiving below 35MHz; it will just be more sensitive to noise. By placing the antenna of this receiver next to your servos and then moving them you will be able to hear any electrical noise present. The same technique can be used to determent the noise level of a petrol engine's ignition system. Most petrol engine pilots would be shocked if they heard how much noise they generate! The fact of the matter is that any petrol engine plane will have less range with the same 35 or 50 MHZ equipment than a glow powered plane. The 50MHz equipment will be slightly better than the 35MHz equipment, but the best equipment to use with a petrol engine is 2.4 GHz equipment.

The article on batteries was interesting but I do not agree that nickel metal hydride batteries have a lower self discharge as nickel cadmium batteries. NiMH has a much higher self-discharge rate than NiCd. Its self-discharge is 5-10% on the first day, and stabilizes around 0.5-1% per day at room temperature.The rate is strongly affected by the temperature at which the batteries are stored with cooler storage temperatures leading to a slower discharge rate and longer battery life. So it is important that you charge your NiMh batteries the night before you go flying and not after you have been flying! A new type of nickel metal hydride battery was introduced in 2006 that claims to reduce self-discharge, and therefore lengthen shelf life. By using a new separator, manufacturers claim between 70 to 85% of capacity is retained after one year, when stored at 20 degrees Celsius . These cells are marketed as "ready-to-use" rechargeables, and are targeted towards the digital camera market, where the equipment is only used a few times a year. Users must be aware that a normal NiMh battery deteriorates during long time storage. This problem can be solved by charging and discharging the battery several times before use. One of our CRF members recently bought a new hi-capacity NiMh pack to replace his suspect pack. He then charged it only once with his "smart" Swallow charger. During his second flight of the day the PCM receiver went into safe-mode, due to low battery voltage while the plane was in a dive, his beautiful Genesis was demolished.

Lekker vlieg
Piet Le Roux, Bloemfontein.

(Originally posted on the SARFLY list)

Saturday, August 11, 2007

Buddy Wright

The aeromodelling world is infinitely poorer with the untimely death of Buddy Wright. He departed for a better place on Friday 10th August.
Our sincere condolences to Neville and the rest of the Wright family.
Our thoughts are with you.

Bob and Marietjie

Blog Archive

Total Pageviews


Web site terms and conditions

Copyright of material on all the pages of this site is vested in the SAMAA or the original authors. You may use the material in terms of the Creative Commons license for non-commercial purposes on the condition that you acknowledge its origin.

This work is licensed under a Creative Commons License

The views expressed on this web site, or on any directly or indirectly linked site, are not necessarily those of the SAMAA Committee, or the web editor. The information provided on this site is provided for recreational purposes only. The SAMAA and the authors of presented content assume no liability whatsoever on the use of information contained in this site. The information on this site is provided on an "as-is" basis, without warrantee of any kind. Links provided on this site will let you leave the SAMAA web site. The linked sites are not under the control of the SAMAA, and the SAMAA is not responsible for the contents of any linked site, or any link contained within a linked site, or updates to such sites.