F1Q Discussion on SEN

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    I don’t know how many people subscribe to Roger Morrell’s FAI newsletter as I do but the is an interesting discussion going on there regarding F1Q rules. One poster is urging that CIAM not adopt rules that will make F1Q inot an expensive development race as is true of so many other F1 classes.

    Here are a couple of messages that were posted:

    Q answers from someone who flys it!

    Andreas Lindner

    Hello Roger,

    please publish this article as my answer at the both articles about the F1Q
    rules from the last SEN. Thanks!

    Thoughts about F1Q

    The day will come, when the current F1Q-rule with a maximum battery weight
    and a specified motor run will not restrict the capacity of the class within
    practicable limits anymore. To prevent from problems similar to F1A,B,C and
    their high performances – based on expensive technology and exceeding the
    scope of most flying fields – I propose to think proactively about
    measurements and their directions. If the CIAM F1 Subcommittee would agree
    in these measurements, F1Q flyers could develop their own strategy within
    the defined common sense.

    I wonder whether a reduction of battery weight and a shorter motor run would
    do the job. And I doubt: Any reduction of the duration the motor runs will
    be followed by faster climbs of the models. Inevitably the loads on motor
    and battery will increase, shortening their life and raising the costs.
    Expensive technology of very high quality will offer decisive advantages.
    This quality-advantage will be even more critical, if CIAM decides to reduce
    the maximum weight of the battery at the same time. To avoid this
    development, it would be much better one defines a relation between motor
    set and model size. That relation might also support the great variety of
    models which originally had been intended by the very open F1Q formula CIAM
    passed a few years ago. Following guidelines discussed with active F1Q
    flyers, I therefore propose:

    1. Add to the limits within the current rule a maximum weight of the motor;
    let’s say 12 % of the total weight of the model.
    – The formula will get less dependent on the battery technology which can’t
    be foreseen.
    – Rather than the capacities of the batteries, the specific power of motors
    is unlikely to go up excessively.
    – Less need to torment the battery in order to gain more power.
    – Exchange of motors – if necessary – is easy. Model could remain unchanged.
    – The weight of the motor shall include cables and connectors, the fixed
    driving axle and the related cogwheel, not the gear itself.

    2. Change the maximum weight of the battery (90 g for Lithium batteries in
    the current rule) to 15 % of the total weight model.
    – Battery size related to model size offers better opportunities in
    designing different types of models which might all be competitive. Any
    absolute size of the power source will create uniform models, which is
    against the idea behind the introduction of F1Q. Further on, developments
    directing to small and fast models with a high wing load – comparable to
    small F1C – get out of interest.
    – Every F1Q model builder is free to define their best combination of
    battery and model size or model weight, related to that very battery which
    seems to offer the best performance.
    – If necessary, the relation may be reduced without generating costs and
    efforts (batteries are about to be changed anyhow from time to time).

    3. Keep the motor run flexible
    The duration of the motor run during competitions should be kept flexible
    (some Contest Directors in 2008 weren’t aware of their freedom). High level
    competitions like World Cup events might be dealing with 15 sec in general.
    Nevertheless, some competitions demonstrated a modified motor run being a
    perfect means in the event of recovery problems or to suit meteorological

    Further measurements to think about:

    ·If the performance of the class in future can’t be restricted within a
    reasonable limit, despite of the proposed weight-related formula, CIAM might
    follow the F5D class in introducing an energy limiter. Advantage: Precisely
    defined energy. Disadvantage: A lot of work with model processing, which
    doesn’t fit to a typical free flight contest.

    To avoid developments into the extremes, CIAM might introduce a maximum wing
    load of 20 g/m² and restrict the surface of wing and horizontal tail plane
    to maximum 40 dm².

    Introducing condensers, so called Supercaps or Goldcaps, is not a good idea.
    Relation between energy and weight is worse compared to Lithium batteries,
    and one would need special electronic systems to compensate an uneven power

    Andreas Lindner

    Q rises in the UK


    Having observed some tremendous F1Q climbs at the Stonehenge Cup and British Nationals I think the above 1000ft climb is with us now. The motor run needs a drastic cut.

    Peter williams

    F1Q Power Restrictions

    Tapio Linkosalo

    Klaus W. Salzer wrote:
    Another clear indication that the rules in F1Q have to be changed … how
    is still not clear!

    In SEN 1301 Klaus brought up again the question of F1Q power limitation.
    I totally agree with him, that the current rules allow the models to be
    ridiculously over-powered, with people using motor runs below 10
    seconds, while 20 seconds would be allowed! I think everyone sees, that
    a major change in the rules is to be expected, and while that statement
    is written on the wall, it puts many people off, delaying them from
    trying their hands on F1Q. I can tell you that surely it puts me off; I
    am most interested in the class, but do not find it reasonable to to
    invest time and money, while all the effort will be in vain in a year or

    So, while CIAM seems to be unable to take any action in this matter, I
    suggest an open discussion and hopefully an agreement on a limited set
    of rules for F1Q. These rules could then be applied as an unofficial
    subclass for F1Q in some contests (like Nordic, Baltic etc.), and if the
    “limited” set of rules shows to be working, they could be then presented
    to the CIAM as a new, but tested proposal for the F1Q rules.

    What should the limited rules then be like? In my view, the power should
    be restricted to a level where a spiral climb of 15 to 20 seconds is
    required. F1C has shown, that over-powered models and reduction of motor
    run will lead into rather dangerous models, that are indifferent in
    stability and very sensitive to launch errors. A slower spiral climb
    requires the model to be stable, and therefore it will be able to
    correct some error or bias in the climb attitude.

    The big question is now, how to limit the power? I do NOT think that
    electric devices, such as “black box” current limiters or energy timers
    are the solution. It is rather difficult to verify, whether these work
    as they should. It requires good quality electronic measuring devices,
    and some expertese to use them. The same applies also to the concept of
    serial resistor limiting the current to the motor (my previous pet
    idea). However, I recently learned that an RC soaring club “Albuquerque
    Soaring Association” has for a few years applied a set of rules to limit
    the power of their models, that is rather straightforward and easy to
    verify. The rules say:

    “Motors are restricted to out runner type without gearboxes. The
    maximum size of the flux ring is 28 mm in diameter and 16 mm in length.
    Batteries are restricted to 7 Nicd / Nimh or 2 lithium polymer cells.”

    Thus the rules are straightforward, and it is easy to verify with simple
    calibers, that the motor is within the restrictions. But most of all,
    the beauty of the rules is that restricting the motor size quite
    efficiently restricts the maximum (output) power of the motor. If you
    want to “push” the motor by using larger prop than is the most
    efficient, you indeed can increase the current to the motor, but that
    makes the efficiency of the motor crash, and out output power does not

    The ASA rules have resulted in Hacker A20-20L being the most widely used
    motor, and that can draw up to 20A of current, which means around 150
    watts of input power (remember the 2-cell restriction!), and some 120 to
    130 watts of output power. That might be quite sufficient for a A2-sized
    F1Q, maybe too much for smaller models.


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