F1Q Discussion on SEN

[Anonymous]

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.
Reason:
– 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.
Reason:
– 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
conditions.

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
supply.

Andreas Lindner

Q rises in the UK

Roger

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
two.

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
increase.

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.

-Tapio-

[Author]

Posts