Committee:

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

Representatives:

HTL - Gordon Browne : Bill Vos Memorial - Dennis Bird : Postals - Jan Sime : F3B - Nigel Wilkinson/Jan Sime : F3J - Ian Sime : F3K - Brett Lewis : F5J - Mike Vos : 2 Meter/New Commers - We need a rep please :
Slope - Izak Theron(Gauteng) Rus Conradt (KZN) Kevin Farr(WC) : Scale/Cross Country/GPS Racing - Chris Adrian


Calendar: Jan Sime & Gordon Browne


05 October 2009

2009 Nats - F5J Report

If I remember correct the first Nats where I flew an F5J event it was at Groengoud 2006 Nats. At that stage mostly S400 motors were used. The launch times were 60 to 90 seconds if you found lift soon. I think Dion or Mark won with a Graupner Culumlus 1.8m S400 glider same as what I was flying at the time.

The entries have increased steadily the past 4 years for the event. This year we had 13 entries, the second largest number per category following F3J/EW. The models covered the spectrum from the foam ARF models (Wolfie, Zimmy, Craig/Tshepo), Balsa 2m ARF (Lionel), 2m Tsotsi-E (Rudi) , Purpose built balsa/composite 2.5m (Gert), Troodon 3.7m (Simon), Ex-Pro/ shadow with motor pod on wing (Herman, Paul), XPro-E (Johan, Dion used 2 moldies, although I only saw the 20" prop) to a 1.4m E-Hawk (Craig, it always looked high but was only 'cause his model was so small).

All the motors used this year were brushless and in most cases Lipo battery packs were used. The format of the event is similar to F3J where your launch time (motor on) is subtracted from the flying time of 10 minutes. A re- launch is allowed with the penalty of losing the landing points to a max of 30 points. This allows for some strategy to be worked out on each flight depending on the air conditions. The objective would be to reduce launch time and find lift for the rest of the 10 minutes. The choice is yours how high you want to launch and reduce risk of not finding lift.

From the scores I see the motor on times were at best 20 seconds and worst 120+ seconds. The competitive models were averaging 40 seconds and less. My launching time is between 10 seconds and 15 per launch. In order to optimize this, a tradeoff is required between motor /battery size and airframe weight. I would be able to improve my launch times but the lightly constructed airframe would not be able to withstand that. The molded models can withstand higher powered launches, but would need a thick checkbook to afford a power system to do better launch times. As proven with this Nats the launch times is a factor but if you are able to thermal and read air well you will come out tops.

Johan did very well with his eX-Pro. He made his 10 minutes in most flights with only one launch and added the landing bonus. I think Dion missed the podium due to a misunderstanding of the rules on landing points for round 1. I had to use 2 launches most of the flights and lost my landing points, but due to the fact that my motor on times was very short, I gained in score.The moldies with motor pod was most interesting to me. This allows you to convert your standard F3J glider to a motorised electric model with little effort. According to Paul/Herman the pod do not have any significant effect on the model's performance. These accessories can be acquired from SoaringUSA.com at around $400.

Stats of motor setups I could get hold of:Dion: 1. Xperience Pro-E, 4s Flightpower 2150, ESC CC 60A with BEC. Kontronic FUN600 1500 u/V with 2/1 gearbox, Graupner precision spinner, Freudenthaler hand laid carbon 20x16 prop! Problems were experienced due to overheating of the BEC2. Eish 4S Flightpower Green, Hobbywing 65A ESC, Kontronic Fun 480 with 4/1 gearbox, Graupner precision spinner, Graupner CAM prop 13x7.

Johan: Xperience Pro-E, Scorpion motor & ESC, 4S 3300, 12x6 prop.Gert: SP2.5 , E-flight 15, 4 cell 2200, 13x8 prop (details on blog www.rcgroups.com/forums/member.php?u=16783)

Simon: Troodon, 3 cell poly, outrunner, 14 x 10 prop (supposed to be a Kontronic 480-33 but it burnt out in another model)

Lionel: Primera "Flaper", 2.7metre span , Axi 2814/16 motor, Scorpion Commander 35A ESC, on Flightpower EON 250 mAh 3S battery. Prop was a Graupner CAM 11x6.

Herman & Paul: F3J Xperience Pro, pod motor, folding 13x8 props, 3s LiPo

I hope our new F5J Rep Juanita Smith will organise more events for us during the next year.

Cheers,
Gert

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