National Free Flight Society

SEN 3144

  1. Organizer’s Altimeters?
  2. We need to reduce performance!
  3. Sierra Cup
  4. Kotuku Cup
  5. D47 Replacement

Organizer’s Altimeters?

By Aram Schlosberg

SEN 3141 had a proposal by Laurent DUPRIEZ that the organizers should supply two blank altimeters to each flyer in a flyoff.
Requiring the organizers to supply two altimeters per contestant is problematic. If the altimeter miss-functions what remedy can be offered to the flyer? And if they have their own altimeter, can it be used instead?
And when there are an insufficient number of altimeters, would some only get one altimeter? Purchasing lots of altimeters is not cheap. Will they be used in subsequent World Cups or loaned to other organizers?
Currently, altimeters are the responsibility of the FLYER. It’s part of a model’s equipment, a fix cost that can be shared across models. The legend that junior flyers can’t afford to acquire an altimeter pops when one accounts for the true models’ costs and the expense of participating in distant contests.
A final note. I advocate that altimeter readings to be acceptable in ALL regular flights. They matter when the max is missed by 1 or 2 seconds or in attempts. A flyer could be limited to ONE challenge per contest to reduce organizers’ overhead. ///


We need to reduce performance!

From: Klaus Salzer

We need to reduce performance!
With the present rules very often more than 50% of the participants reach the flyoff – a clear indication that the rules do not fit the models any more! There are hardly any flying fields available where even with moderate wind speeds the current 4min/3min maxes stay on the field … not even talking about “staying in sight”, which is even different can of worms in Europe with the drone legislation.

Here are some crazy Ideas about reducing performance:

reduce towline length. Maybe only for flyoffs? If there is a clear rule, say 35m first flyoff, 20m for all further rounds people could prepare setups and train with these lines.

reduce rubber, again maybe only for flyoffs. Indoor flyers regularly do test flights with half rubber – what is it that they do better than we outdoor freaks?

most problematic. Motor runs are too short right now for easy timing. We may need a completely different approach. How about looking to the control line tem race guys, who limit the amount of fuel? I have no idea which amount would serve and how to solve it technically, but it would open up the option to use a low power, low consumption, long run against a high power short run. And again it would allow reduced “energy” for flyoffs. The “low tech” solution could be what we used as children (60 years ago): We had no timers … motor run was limited by the length of fuel line from a tank which was removed at launch (no pressure feed, no lood off, no precision … but worked).
Crazy idea … do you have better ones?

All these ideas would not make existing models obsolete, but would require a bit different approach to trimming and knowing your plane.

Regards from Austria



Sierra Cup

47th Annual Sierra Cup

An FAI Free Flight World and America’s Cup Event October 3rd-9th, 2023
Sponsored by Southern California Aero Team
Lost Hills, California, USA


Schedule of Events:

Tuesday, October 3rd:   F1E On the Hill at 10 AM for 5 rounds. Peter Brocks is CD. Kotuku F1E will be flown the next day, Wednesday, October 4th.

Thursday, October 5th:  The “Mini Events” F1G F1H F1J and F1S
There will be five (5) one hour rounds beginning at 10 AM with 2 minute maxes. Fly offs if necessary with be announced at the end of the regular rounds. Maxes will be announced prior to the start of each fly off round.

Saturday, October 7th: F1A F1B F1C F1Q and F1P
Seven (7) one hour rounds will be flown from a line as opposed to poles beginning at 8 AM with extended maxes of 240 seconds for the first and SECOND rounds with the exception that all regular round F1P maxes will be three (3) minutes. Fly offs will be scheduled following regular rounds. Any fly offs required after Saturday will be flown Sunday morning with a 10 minute max. The reserve day for these events will be October 9th.

General Rules:

The contest will be run to current FAI rules and Sporting Code with the exception of the use of lines versus poles. Max times may change to accommodate weather conditions. No moto-flapping is allowed.
This is a time one/fly one format so buddy up with a fellow competitor for timing.
FAI competition number is required for the Large events if flying for World Cup points. Speed limit on all roads is 20 miles per hour for dust mitigation.

Entry Fees:

Mike McKeever-CD (916) 390-3212

F1A F1B F1C F1Q F1E          $35 USD F1G F1H F1J F1P and F1S                                       $20 USD
Junior entry fees are $5 USD for any event

Flyer here

Kotuku Cup


Oct 4th – 8th, 2023 at Lost Hills Field, CA. reserve Monday Oct 9th

Sponsored by Southern California Aero Team

Tuesday, Oct 3rd SIERRA CUP “F1E” see separate flyer

Wednesday, Oct 4th KOTUKU CUP F1E 5-50minute rounds-10 minute break starts at 10:00 am
Thursday Oct 5th Sierra Cup Mini’s See separate flyer Friday OCT 6th F1G, F1H, F1J, F1S

One hour rounds starting at 8am

Flyoffs max and start time posted after last round.

Saturday, October 7th SIERRA CUP See separate flyer Sunday, Oct 8th F1A,F1B,F1C,F1P,F1Q
Seven [7] one hour rounds start @ 8:00 AM with extended max times F1A, F1B, F1C, and F1Q -240 seconds 1st & 2nd ROUND
F1P is 180 all rounds
Remaining round maxes are 180 sec.
Fly off schedule 30 min after end of last round. Event start times will be posted. This is a fly one time one and will be done from a flight line.

Entry Fees:

FAI events: FIA, B, C, Q & E; $35 each
$20 each for F1H, F1G, F1P, F1J, F1S

AMA age juniors: $5/event

Trophies awarded for 1-2-3 places in F1A, B, C, G, H, S, Q, E, J , F1P (1stplace only) Junior Hi-Time Trophy F1A, F1B


AMA membership is mandatory.
FAI license mandatory for A,B,C,Q and E FAI events run to the 2023 FAI rules.

Flight line will move as needed to avoid retrieval from fields of trees. No Moto-flapping.

Contest Director Brian Van Nest Cell 760-937-0177

Pre-registration requested via email, pay on field. Events entered, AMA # and FAI License

Flyer here


D47 replacement

The Dymond D47 was a very popular and reliable micro servo used in both F1A and F1B models. In F1B models it was typically running on a single LiPo as the main servo releasing levers and F1A for  rudder or wing wiggler. Here it probably ran on a higher voltage.

Free Flight Lore has it that prior to 2000 engineers at AeroVironment determined that it would be good for a small UAV provided a small change was made to a passive part in the servo. This was made it very good go the UAV and Free Flight Models and R/C DLGs .

This servo was also sold under other labels, Ripmax etc. This servo was discontinued  much to our collective dismay and people have looked for a replacement.

Recently Miha Lemut asked the Free Flight collective on the FB for suggestions. As he suspected there were quite a number of suggestions.  We publish an edited list below and give credit to some of the suggesters.

There is one item that was not an issue in before 2000 was the issue of susceptivity of the servo to RF, EF or MF interference.  I understand that a number (all?) of the onboard GPS systems manufacturers that we use have found the D47 susceptible to interference and recommend filters.  The same GPS guys say that other (more modern) servos are better.  While the FB list discussed quality and weight stated vs actual  measured none mentioned this

Note the list does include some links to manufacturers and shops, this is not exhaustive and typically there are a number of suppliers.

Mórocz Péter
For rudder Futaba S3114 would be enough

Loet Wakkerman
Much better than the Dymond.

Mihály Váradi
The corona ds-843mg servo is 11 gr but some places say it is 8.5
Other Coronas may be better

Bill Kuhl

FOSA EMAX ES9051 4.3g Digital Micro Servo

Michael Zagora
Emax es9051 or Chaservo DS06

Serg Vorvihvist
KST X06,

Mihály Váradi
Power HD DSM44 Digital Servo 1.6kg/cm 6V

Tony Mathews

LV06 Sub Micro Servos 0.05sec 17N Coreless DC Motor CHASERVO
Chase Servo have a number of different 06 models e.g. LV HV  different voltages etc make sure you choose the right one
This is designed as a replacement for the Dymond D47. Very good quality and high accuracy. More expensive but higher quality materials

anything else ?