Saturday, June 30, 2007

35 MHz interference update -- Dave Armitage

ICASA have recently done a survey at Midrand Model Soarers field to ascertain what was causing some heavy interference on certain spots in the 35 Mhz band. It was found that ESKOM seemed to be causing the problem with arcing on some of their ultra high voltage power lines. I have requested a full report from ICASA. At present they state they have informed ESKOM of the problem. ICASA want to do another full test at the site before issuing a report. On receipt of that report then I will make it public.
Another site that seems to be experiencing some frequency related problems is JOMAC. This site is also near a heavy concentration of high voltage power cables. It could just be possible that the same sort of hassle could be happening there.
I am awaiting fault reports from pilots at JOMAC before initiating a survey there.
Dave Armitage

Tuesday, June 26, 2007

2007 F3K Nats -- Mark Stockton

More info here.

World Model Pylon Racing Championships -- Peter Eagle

Hey all pilots with any interest in our WC teams

You may know that SAMPRA as the pylon racing SIG of SAMAA currently has an official, 3 pilot South African team at the pylon racing world champs at AMA headquarters, Muncie, Indiana, USA.

The team of Trevor Budd, Andre Nortje and Russel van der Westhuizen as well as Wayne Wilcox and other helpers and supporters have spent huge amounts of time, money (their own) and effort to get to the world champs. The team has been at Muncie since late last week and have been using the time to practice and adjust their equipment to local conditions. (Elevation about 1000 feet or less, hot and humid climate at this time of year)

After official practise yesterday Trevor reports via SMS " Some times from today in Richards Bay like heat - Trevor 1:06 (66 seconds); Andre 1:09 (69 seconds) and Russel 1:12 (72 Seconds) Top 12 all running 57 to 60 seconds. Please let the guys know."

I then posed a question regarding reliability and repeatability as often the very fastest have issues getting in all their times and hence a slower but more reliable setup will make for better results in some cases. Trevor replied " We are getting there. Lots of broken pipes and engines in the beginning but we are now happy with the setup. A bit slower but reliable"

I trust that all pilots with the slightest interest in these amazingly fast, expensive and temperamental planes will wish our team all the best of luck.

I will post further updates as I receive them but the German team has a regular daily posting on

Update 27 June 2007 -- link to official web site here.

Peter E

Saturday, June 23, 2007

SAMAA Insurance Cover -- Piet le Roux

Piet makes some interesting comments here. I've asked Joe for a formal response from the SAMAA insurance broker but to date I have not had this. I'll post it when I get it. John

Like most of us I partake in this hobby for relaxation. Knowing that I am insured makes me more at ease while flying. But after reading INSURANCE SUMMERY in the March issue of SAMAA news and then reading the POLICY ON LODGING AND PROCESSING AN INSURANCE CLAIM issued by SAMAA I have a few questions about the policy.

The policy covers the association in respect of liability for injury or damage of property, arising out of the activities of the association and we are told that we are very fortunate to have this policy. I can appreciate that insurance in the aviation field is very expensive because of the high risk factor and the very expensive equipment involved. Most aircraft accidents also coincide with fatalities, very few people have been killed with model aircraft. To classify model flying as aviation in this case is nothing more than a sales pitch. The 10 million Rand cover sounds very impressive but the fact of the matter is that South African law does not allow for big liability claims like in the USA. To be successful with such a claim in the RSA you must first prove that the perpetrator could have foreseen the accident and did nothing to prevent it, or/and that he did not adhere to safety guide lines and therefore acted negligent. I would like to know what the biggest settlement claim in South Africa was when an accident occurred while nobody acted negligent? The problem is that the policy only covers the association if its members involved did not:

A) Fly reckless and dangerous.

B) Fly a model aircraft while under the influence of alcohol or judgment impairing drugs.

C) Operating a Model Aircraft which do not comply with the Manual of Procedures.

D) Intentionally fly over an active public thoroughfare, roads, over spectators or members of the public.

In other words did not act negligent.

So the 10 million cover now becomes a joke because there is absolutely no way that the association can be liable for that amount if no one acted negligent.

If the guidelines laid down by the association is found to be inadequate or the field registered by the association is found to be unsafe or/and there were not adequate signs to warn the public and as a result a liability claim against the association is successful, why should the member or members involved be responsible for payment of the excess amount? His club and the association are at fault and they should pay up. In any case remember it’s the association that’s insured and they are the policy holder so the association should pay the excess amount. If one takes in account the amount of member’s funds that was given to transformation in 2006-2007, it should be easy for the association to build up a reserve fund to pay any excess and assist members when an accident occurs.

The policy also does not cover the association against any accident involving a full size or manned aircraft because full-sized or manned aircraft have over riding right of way. This is unacceptable because any full-sized or manned aircraft that flies over a registered model airfield at a dangerous height is breaking the law. The model pilot have to keep his plane in sight at all times, if a full-size plane approaches from outside his field of view, he could react too late to avoid an accident. The plane could be a glider or had a dead stick, in which case he would not hear it coming. The model pilot could even be a deaf person.

The bottom line seems to be:

If an accident occurs while you were negligent or a court finds that you were negligent: you are not covered.

If the accident involves a full-size plane: you are not covered no matter what.

If you were not negligent: you are covered but you probably would not need it!

Piet Le Roux


Wednesday, June 20, 2007

A proposal for Park Flyer regulations -- Alan Fraser

Preliminary thoughts on the Regulation and Control of Park flying in RSA.

1. Introduction:
Park flying is here to stay! The progress of technology in recent years in the areas of electric propultion, power sources, materials, construction methods and radio equipment, has made it possible to fly r/c models in much smaller spaces than we have been traditionally used to.
This has resulted in an ever increasing number of pilots flying their models from sports fields, open urban velt areas and even indoors in sports and school halls, from here the advent from "park" to "indoor" flying.

2. SAMAA and park/indoor flying:
SAMAA has the responsibility of regulating and controlling all r/c flying activities in the RSA. SAMAA has therefore started a process of looking onto the phenomena of park/indoor flying in an attempt to establish the ways and means for it`s members to participate legally in this fast growing dissipline of our hobby, in a safe and controlled manner at recognised flying sites with insurance cover and, without interfering with other RC flyers.
This regulation process obviously needs to be done in such a manner that the enthusiasm and growth of park/indoor flying is not dampened.

3. Definition of a park/indoor flyer:
"A small and light electric power driven aircraft that can be flown in a confined area such as sports fields or indoors in a hall".

4. Specification suggestions:
4.1. Aircraft:
Wingspan: 1,2m max.
Weight:1kg max including battery.
(Note: This specification will force a trade-off between the model type, size, mass, and the limits of the specification ie.: a glider type model will fit into the 1,2m wingspan, 1kg limit, but a power model might have a reduced wingspan for the same mass.)
4.2. Helicopters:
Main rotor diameter: 800mm total max.
Weight: 1kg max with battery.
4.3. Propulsion:
Electric power only
4.4. Flying sites:
"Field" size app. 100m x 50m (outdoor.) Hall size app. 35m x 20m (indoor.) ie.: Rugby, soccer type sports field.
*Park flying sites are to be at least 2,5km apart, and at least 5km from normal R/C flying sites.
4.5. Airspace:
All flying to be done within the perimeter of the field used, to a max. of 50m high.
*This is a very important restriction as it will ensure that the pilots fly the type, size and weight of aircraft that is within their proficiency and skill level, to stay within the boundaries of the field that they are using.

5. Management and control:
5.1. In time all park/indoor flying sites will have to be registered with SAMAA as such.
5.2. Each site will have to be under the control of a club committee or a responsible person.
5.3. Normal SAMAA safety rules are to apply, ie.: Frequency control, spectator lines, no-fly areas, pilot proficiencies, SAMAA membership, insurance cover etc.

6. Process:
6.1. Publish the draft suggestions in the SAMAA news and website for comment by members, refine the document to final publication.
6.2. Draw up a database of sites being used for park/indoor flying.
6.3. Register as many of these sites as possible with SAMAA.
6.4. Encourage as many people as possible to make use of these registered sites, and to stick to the aircraft specifications, through SAMAA news, website and distribution of a SAMAA park/indoor flying leaflet through the dealer network.

7. Conclusion:

We have to start somewhere. Please address your comments to: Allen Fraser, the Chairman of the special committee on Park Flying and the SAMAA Dealer Association
Tel:012-362 4925 • Fax:012-362 4926

for what it is worth my comment to Alan is here. John

Four Wheel Drive Club -- Dave Armitage

Hi Guys,
The SA 4 wheel drive club are being very considerate with their help and they are forwarding the info on their events to me. The latest event will be held in Ermelo over the weekend of the 30th June, 1st July. They will be starting at +/- 16h00 on the Friday to +/- 20h00 on the Saturday evening. Spots in use by them will be 35.225 Mhz and 35.250 Mhz. 35.300Mhz will only be used in an emergency situation. In the meantime it is still recommended that pilots stay off the two spots on either side of 35.225 i.e. 35.220 and 35.230Mhz, plus 35.250 and 35.300. This applies especially around the Ermelo area over that weekend
Dave Armitage

Tuesday, June 19, 2007

The Stick; or the Carrot?

There are many advantages of the SAMAA membership for Aeromodellers. I find it strange that the latest issue of the News persists with a heavy-handed approach. I'm not sure if comes from the editor or from the committee. I suspect the latter. Have a look at the insert on the last page. It's called "Why all Aeromodellers MUST belong to SAMAA". There are two statements that are patently wrong.

The first; "SAMAA membership is a requirement for YOU to legally participate in any aeromodelling flying activities (in terns of site, height and weight) which falls under the legal mandate of the CIVIL AVIATION ACT".
I don't know from where this extraordinary statement comes. I've asked the question but no one seems to be able to answer.
Here's my understanding of the matter, (and you can find the documents on the SAMAA web site here ).
The CAA has devolved certain of its administrative processes to the Aero Club. In turn the Aero Club has passed onto the SAMAA duties to administer all aeromodelling in SA. The SAMAA must do this for members and non-members alike. The difference being that non-members may be charged for service on a cost recovery basis. Nowhere is there any suggestion that it is illegal to fly if you are not a SAMAA member.
I suspect that the Big Stick approach is driven by the laudable objective of increasing SAMAA membership. There is evidence that it has the opposite effect.
Surely the best way to get more members is to show the benefit. It's the old story of Selling. To sell, you must expose your product to the risk of being sold. Show non-members benefit, help them, encourage them, and they will join. But whatever else you do, don't bully them.

The second; "SAMAA is responsible for the regulation and control of all RC radio frequencies, used for model flying purposes". The latest uproar over interference on the 35MHz band gives the lie to this. The SAMAA has no power to regulate and control frequencies.
What it does, and it is a vital role, is to act as liaison between Aeromodellers and ICASA.
Let's stop the wild talk of licensing, restrictions on who may buy radios and so on. What's needed is a helpful constructive approach. (And in this regard you may like to read again Piet le Roux's note).

For the SAMAA to deliver fully on the promise of its ARO status I suggest a little less hubris and a little more empathy.

Sunday, June 17, 2007

Electric not yet there -- Neil Allen

A month or so ago Burt Botha sent an email saying that all F4c Pattern fliers should go electric at once. I want to give my views, and maybe open a flame war or serious debate,

Burt said that pattern fuel needs 30% nitro methane and costs R25 a litre, then wonders why no fliers use four strokes. He just gave the answer, as two strokes run 10% nitro and cost only R8 per flight. S A Modellers tried four stroke motors, and I saw Chris Harris struggling with inadequate power at a Bloem Nats. The 0S 140 is the nicest motor ever built, with a lovely carb pickup, easy start, and reliable idle of 2,000 rpm These are universal in SA because they use cheap 10% fuel, and have plenty of surplus power at 5,000 feet. Hell, at 2,000 feet I restrict the throttle opening to 75 opening to keep the speed down, which I have never done to any engine before

We wont go four-stroke as the power is less, and the only advantage is an idle of 300 rpm slower, which really doesn't count. Tough luck if the judges overseas prefer them

As for electric, you glossed over the costs.
Already in my club I am considered the fat, rich, capitalist, as I can afford R7000 for the airframe, R3500 for motor, R800 for pipe, and a few digital servos, totaling R12 000. I get an OS140 plane, and I adore its flying characteristics (much nicer than those large scale Extra jobbies with petrol engines that cost R20,000)

Now Burt wants me to go to electric power. To get an afternoons practice of four flights I need 3 batteries at R4,000 each, for R12,000. I need two high rate fan cooled chargers for the field for a few thousand more rands. I need 2 of 12 volt deep discharge batteries to run these chargers (say R900). I am told that if you use the car, it will be too flat to drive home. If I use the car running with alternator it will burn that out for R5000 rands. So I go flying with three batteries, which I charge at home with, the 2 or 3 lead acid re-chargers.

I fly on one pack. The performance is inferior to a tank of glo fuel, as I usually do a pattern and three more minutes of practicing man oeuvres, even including hovering. But batteries get weaker throughout the flight, and cannot do this.

The total cost to go electric is maybe
Plane R9000 (covered)
Motor and controller R5000
Batteries R12000
12V Chargers? R3000
Field Chargers R4000
TOTAL (approx) R34000

R34000 is a LOT different from R12000. Maybe some factors are fudged, but that is more than I like spending on modelling. For that price I could get a scale turbine plane (not that I actually like turbines - 5 second motors lag is a total disaster!)

Then you take on a full time job of babying those cells. According to the Bob Violett site on electric ducted fans, they run pattern plane size cells and motors. They say that if it rains one weekend you must discharge all your cells to part charged to save their life. How many hours would it take to do this: -
Carry 12v lead acid batteries back from the car to the garage (don't forget they are strapped in to avoid smashing your car when you hit brakes)
Charge lead acid charger batteries (we haven't even included this cost yet)
On your explosion proof place you run down each pack in turn to 75% charge
Note that the instructions say that you may not leave them unattended, or do any charging while traveling in your car.
Next weekend you use your special balance charger to fill up all cells again (3 hours work). Top up the 12v batteries again
Load 2 X 12 v chargers into boot, using special straps

Come on, be serious, how many S A modellers will rush out saying "yeah sure "R34,000 is fine - give me one, and I am happy to take over babying those batteries"

Burt's electric F3A does fly very well, but not that much better. I can see that he is an "early adopter" who loves new technology, and in a few years we may follow him, but not yet, no thanks
Neil Allen

Wednesday, June 13, 2007

News of Oudtshoorn Scale -- Fanie Fourie

Oudtshoorn Scale 2007 is around the corner and we are in the final stages of planning and we have the great pleasure to invite all of you to come and join us at this great event from 20th to 24th of September 2007.

This year we will be attempting what some might say is impossible but that is the Cango Flying Club spirit. We have received permission from Guinness to attempt a world record for the Guinness Book of Records for the most Radio Controlled Scale planes in the air at once. We received confirmation two weeks ago and fear that we will not reach everybody in time through the July/August issue of SAMAA magazine.

We would like all of you that are willing to take part in this event to book your spot through Hekkie Fourie as soon as possible. We want to accommodate as many pilots as possible and want to allocate alternative spot/frequencies if necessary. The sooner you confirm with him the better your chance of securing your spot/frequency and also state the type of plane so we can plan the flight line groupings and circuits accordingly. If you are not interested in this attempt but know of someone who might be, please spread the word in you respective clubs, neighbourhood, town, city or nearest illegal park flyer site!! LOL

This attempt will only be possible with your assistance so please respond as soon as possible. Every pilot will receive a Guinness certificate stating his/her participation in this record attempt, this will be a once-off opportunity so act quickly. The attempt will take place right after the Sunday Church hour as not to interfere with the weekend's general flying!!!

To book your spot/frequency mail Hekkie Fourie at and any additional questions can be directed to Arenhold Hooper at or Fanie Fourie at

General entry forms for Oudtshoorn Scale will be available on our website from next week onwards:


Fanie Fourie

Monday, June 11, 2007

War Bird Day at Swartkop -- Photos by Rudi Venter

And here's another twenty eight pages of Rudi's pictures. That should keep people quiet for a bit.

Is 35MHz safe? Piet le Roux

Is 35MHz safe? Is any radio communication 100% safe: no. But is it safe enough: yes. Even 2.4 GHZ could have problems when we move into the next solar peak (2010 to 2013).The 35MHZ can also experience interference from very far away stations during peak solar activity, hams have communicated around the world on 100mW during high solar activity. Although a solar flair are more likely to strike during the peak period of a solar cycle it can happen at any time and it does generate a lot of noise on 2.4GHz.

But I have only once experienced interference on 35MHz and that was when a novice switched on his TX without checking. Luckily his antenna was not out and I still managed to land.

The problem with scanners is that they are made to receive over a very wide frequency range and there for can not have very good front end filtering. So if it receives an unwanted signal in the 35MHz band it could be an "image" that it's seeing of signals on other channels and there maybe nothing there.

Cheers Piet le Roux

Tuesday, June 05, 2007

Saturday, June 02, 2007

53 Mhz -- Dave Armitage

This has always been a band for model control from way back and it was mentioned in the 1997 project Sabre. (I was also involved with this too) I have taken this up with ICASA and it seems "it was missed out by them" It is available for our use. It is actually part of the ham band, but they have always regarded it as a model control band. I was involved in the negotiations with them to secure the 50 KHz spots a long time ago. In the US of A a ham licence is required but here it is not because of the low power outputs we use, typically 100 milliwatts.

The band starts at 53.300 MHz and goes up to 53.900 in 50 KHz steps
Dave Armitage

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