National Free Flight Society

SEN 1855

SEN 1855 – Table of Contents

  1. Proposed F1C Rule Change
  2. Narrandera 2014
  3. Bicycle at Boulder City
  4. About timekeeping
  5. On time on FB

Proposed F1C Rule Change – editorial

Included in the proposed rule changes for F1C is one that would disqualify the sportsman if his model landed (i.e. Crashed) with the motor running.

This rule has the stated objective of improving safety by encouraging improved reliability and the use of RDT and similar systems.

There is certainly some risk in flying F1C, but all parties concerned from the national Aero Clubs and the FAI to the organizers and sportsmen have a history of general operating procedures, positioning the flight lines and working on technology improvement.

The rules does not appear to be well thought out. In many instances it may be impossible to tell if the motor was running when the model touched the ground, even filming the flight and replaying the landing may not show if the prop was still turning. Similarily if the model landed out of sight of the time keep. In addition it is not clear how the case of mid-air collision would be handled. The collision could damage the fail safe system in one of the models, would that person be DQ’d if, for example the other model came up behind it and chopped it’s tail off. Could the second model get an attempt if he stopped the motor and flight early to avoid a collision with another model. One sees an ongoing can of worms.

Recently we had rule change to F1Q that was not well thought out and put F1Q development on hold while it was straightened out. This proposed change is of many orders of magnitude much more disruptive and could even stop F1C flying altogether.

As expected the F1C community are understandably upset and do not appear to have been consulted. I have seen a number of emails where well known F1C are highly indignant or are proposing solution to address a problem that has not been full defined. In addition some of the suggestions affect the running of other F1 events. Because of the nature of the problem I have elected not to publish this material.

If the CIAM or a member country see there is a problem with F1C, then surely the best approach is to charge the FFTSC or even create a special committee to formally define the problem and take the interested parties, including sportsmen, organizers and vendors to come up with a solution that is best for power free flight in the long term rather than shooting from the hip with a half baked idea.

Narrandera 2014

Three World Cup events for F1A, B and C plus suppporting classes in the “Autumn Down Under” Free Flight Fest at Narrandera, NSW.

Narrandera is roughly equidistant from Melbourne and Sydney – the flying site is huge and the town offers excellent accomodation and amenities. Full details and entry forms available from Vin Morgan vin.morgan . Book your travel now and/or send your entries to the organisers of each of the three events – Robert Wallace, Tahn Stowe or Vin.

Kotuku Cup

April 23 F1B, F1H, F1J

April 24 F1A, F1C,F1G

Robert Wallace : 956 Riverslea Road South, Hastings 4122, New Zealand.

Southern Cross Cup

April 25 F1B, Open Power

April 26 F1A, F1C, Open Rubber

Tahn Stowe: 3/152 Brook Street, Coogee 2034 AUSTRALIA


Australian Free Flight Society Championships

April 27 F1G. F1J
April 28 Comb. % Open, Combined Vintage,Combined HLG, CLG, DLG

April 29 F1B, F1H, Open Power

April 30 F1A, F1C, Open Rubber

May 1 Scramble, P-30, Oz Diesel. Evening. Presentation Dinner

Vin Morgan: 644 Canning Street, Carlton North, Vic 3054 Australia

Bicycle at Boulder City

gil morris <>

For the Finals in October, I’m thinking of buying a peddle bike in Boulder City NV for about $100 and renting a storage space (10′ X 5′) for about $50/mo.Storage would be $600/yr. but with four would be $150/yr. Anyone interested in being one of the four? Then us Easterners can fly into Vegas at anytime and always have a chase bike readily available. I’m assuming peddle bike chasing on the dry lake bed is practical. Further, I assume you can stuff a bike in the trunk of a rental car and drive a few miles from storage to flying site and back,

Alternatively, if you go there just once a year, you could buy the bike and then hide it behind a tumble weed off in the distance noting the coordintes as you leave. Then just hope it’s still there next time out. If not, buy another bike. The basic question is, is it practical to chase with a peddle bike on the dry lake bed and surrounding area?

Editors comment

Gil I understand that the FFTSC spoke with a local who will rent motor bikes or ATVs. Not sure of the status of that ? TSC person care to comment ?

I think that you have been there Gil , riding a bicycle on the lake bed would be no problem, some places off the bed might be difficult.

About timekeeping


I wrote a lengthy message about timekeeping to FB, but I’ll try to
summarize the main point:

Measuring times is like any measurement, it can be considered to
consist of the actual phenomenon plus-minus a measuring error.
Statistical theory of measuring suggest, that in most cases the
average of errors is zero. Therefore, if you measure the total length
of the flight and average the actual measurements (as they read), the
errors tend to cancel each other out. But, if you cut the measurements
to 180 seconds, then you get a skewed distribution of errors, and the
average error is negative, giving an underestimate of the actual
flight time.

This skewed error distribution -> underestimate of flight time is the
problem, that is suggested to be cured by rounding of the times.
However, from measuring theory point of view, the correct procedure is
(as has been the practice in most conditions) to measure the total
length of the flight, average the measurements and then cut the time
to the full seconds.


On Time on FB

David Ackery Another view on this debate, from a purely subjective point of view, does the flight matter if we cannot see it happening ?.

Like the question if a tree falls over in the forest but no one is there to hear it, does it make a noise ?.

Or for example, if we launch an F1D model then walk out of the hall and close the door and come back tomorrow and find it on the floor, does the flight matter if no one was there to see it ?.

I think seeing the model fly is an essential emotional part of our sport.

Tapio Linkosalo The whole problem arises from the false interpretation not to allow to measure time over 180 seconds. So rounding is a cure for a problem that is not real:

The target of measuring times is to determine the length of the _flight_. The rules say that at least two timekeepers need to be used, as in every measurement there is some measurement error involved. Without going too deeply into statistics, it suffices to say that in most conditions the distribution of measuring errors (arising from various sources) follows a normal distribution with zero mean. This means, that if you add up many errors, their mean is zero.

From measuring point of view this means that if you measure each flight to their total length (that is, allow times over 180 seconds to be recorder), the average measuring error is zero (average here means that a single error may differ, but for a large number if flights the average error is nil). Therefore, your average of unrounded times should reflect that of the actual flight, and if you cut the average, you follow the logic that “max is reached when the flight has been over 180 secs; if your average time is 179.nn seconds then the model did not reach 180).

On the other hand, if you do not allow flight times over 180, than means that the distribution of the measuring errors becomes skewed: the errors that reduce the time are allowed, while the errors that give you slightly too long time (but would counteract the under-estimates) are cut. Indeed then you will end up with a flight time estimate that is an under-estimate of the actual time, and you will need to take extra measures (like rounding) to get an unbiased estimate for the flight time. But as written before, that procedure of rounding is trying to cure a problem that initiated of a false procedure of limiting the measured time to 180 seconds in the first place. If you consider each timing as a measurement in statistical sense (consisting of the “real” time and the measuring error), then it is obvious that you need to allow the full flight times recorded!

Aram Schlosberg Yes, the two times are a joint measurement. The reason one should truncates the time over 180 seconds is that it that it could create a max even though the second time is clearly BELOW a max. For example, if the sub-max time is 177 seconds and the over-max time is 185 seconds their average is 181, hence a max! But when the over-max time is truncated, the average is 178.5, rounded down to 178 seconds. (More technically, the standard error of the sub-max time determines the outcome; above 179.5 is a max.)

Chris Edge Aram, I think that is exactly the reason you should keep the current rule ! If the timekeeper makes a mistake and clocks off early you’ll get a sub-max even if you did 10 seconds more via the other timekeeper; this clearly isn’t a good sporting result. This is so easy to do with models low down and out of sight for a few seconds before re-appearing – I’ve had timekeepers clock me off without counting to 10 only for the model to re-appear and do the max. Are you saying the rule should allow this gross error Aram ? CHE

Aram Schlosberg Chris, This is simply a case of BAD timing and if he/she admit a timing error, only the other time should count with a jury’s approval. Basically, we are at the mercy of our assigned timers.

Aram Schlosberg In a communication from Ian, he said that the intention was to AVERAGE and then ROUND DOWN the times (ignoring time above the max). So if the sub-max time is above 179 seconds, say 179.1, the average time is (179.1+180)/2 = 179.55 which rounds up to 180. (179.5 would round down.) In other words, if the sub-max time is ABOVE 179 seconds, it’s a max, and if it’s EQUAL to 179 the flight is 179.

Tapio Linkosalo CHE, I totally agree. If times are 177 and 185 as in Aram’s example, then it obviously is a case of bad timing. But it is an error to assume that the 185 is wrong and 177 is right. In this case the timekeepers should discuss, whether either one agrees that he has made an error, and his time should be discarded. If both claim that their time is correct, then the average should be calculated and the result cut down to full second.

This is a simple case of dealing with measuring errors, and things start to go wrong when you arbitrarily cut the measurements above 180 and produce a skewed distribution of errors.

Chris Edge People make mistakes and there should be ways of dealing with it. You could protest but there could be lots of these for these sort of cases (just look at how many people drop 1 second in contests) and the rules should make some sort of allowance. At the moment they do, with this rule as written I don’t think there will be. I remember timing Randy Archer’s winning flight with two others at the 1993 Champs. Two of us got a perfect run, the third said he couldn’t time it (no other engines running). Two of us got with 1/2 second for the flight, the other over 30 seconds different. If you look at videos of the event which exist you’ll see the three of us went into a huddle to work out the average surrounded by lots of people (no pressure !). In different circumstances the ‘error’ could have lost him the Champs as the final time was less than he actually did. Soon afterwards the rule was changed to allow the jury some discression in case of problems. Why there is now an aim to make matters worse (in my opinion) is bonkers (technical term). I also rather like Dave Ackery’s comment about actually seeing the flight – if we had to rely on altimeters then you might as well just play a computer game in my opinion. CHE

Colin Sharman I agree that you have to actually see the flight, timed to the ground or cessation of the flight if that occurs above the ground. A good example is John Cooper’s 3rd round flight at last year’s WC in France, the official timekeepers gave 179, as did several unofficial timekeepers. The model landed on an area of sunflowers, about 1.5 meters above ground level, and clearly visible. If you don’t insist on seeing the flight you could argue that if the sunflowers had not been there it would have glided for another few seconds and max. I also agree with CHE’s logic for keeping the current rule.

Allard van Wallene One could also argue, if the model is low and a max or not comes into discussion, wether rules are interpreted left or right way ’round, the flight was just not good enough when compared to others’. And that is what competition all boils down to, who is better (in this case, higher to max beyond doubt)…..

Chris Edge Allard we time to an absolute not subjective max. It doesn’t matter if you’re 1′ up or 1000′ up, they all count as a max. If you want to involve a subjective element then fly RC Aerobatics. Contests are not won on who has the better launch, who has the better colour scheme, who had the nicest breakfast that morning, it’s based on people with watches seeing the model fly until they can’t see it anymore or until it hits the ground. There has been numerous attempts to influence results by switching on your tracker loudly next to the timekeeper and shouting “It’s still up !” or saying “My altimeter says it’s still in the air”. If you want to do that then play computer games. CHE

Allard van Wallene This whole discussion proves to me that time keeping has a subjective element to it.

Aram Schlosberg Allard, I don’t think how high the model is when the flight was clocked matters. To illustrate, about eight years ago we had a F1C 10-minute early morning flyoff at our team selection finals. All the models flown within the first seven minutes disappeared into a cloud. Only those who flew later (who had problems starting the motor or an overrun) were seen to the ground and became the C team. (Well, not everyone thought this was a fair sporting outcome, but this is another matter.)

Allard van Wallene Aram, I was referring to conditions like in France F1A fly off last summer. If a model is scraping the horizon leading to plus or minus a second from a max, then for me the models with a clear margin were better. And objective time keeping can only be achieved by electronic means (see for instance the Olympic winter games,
no time keepers with stop watches there…) In my opinion an electronic altimeter supplied by the organiser would be a good start. We could start on a voluntary basis in fly offs. Opt to mount it or not. But then don’t complain if the model wasn’t seen to the ground. At least F1A and F1C have space to mount them, small and light enough (including battery) not to influence flight performance. The Hobby King altimeter could be perfect. The organiser could even store a signature file on the units. Tamper proof.

Editors Note

There is more material on FB and this is following two different paths – one concerning The actual proposed rule and the other about electronic timing approaches. We needed to go to press because of discussion around the F1C Rule Change so will continue this isn
a later issue

Roger Morrell