Well, here we go for another mystery tour, another month, another year and another millennium to boot! Was Santa good to you?? More to the point I guess - have you been good enough for Santa to justify a visit!?!
We had a great family Christmas! It was quiet & laid back and I didnt turn the computer on for nearly a week I built an electric control line model and watched DVDs instead. On several evenings I even managed to sneak down to the local park and fly my tatty old "Etude" and my delta.
For the last few years, I have had the pleasure of being invited into the Childrens Ward of our local Hospital to play Santa Clause for the children unfortunately stuck in hospital over the festive season. This year there were about 45 children, typically 4 10 years old. I had a ball, but boy does that suit get hot after an hour and a half in 30+ deg temperatures!! It also provides a reality check and helps to put your own problems and those of others back into perspective, as well as sorting the real problems from the ones we think are problems! Anyway, Im booked again for next Christmas, and looking forward to it :-) :-)
This month, I have an updated index of links & descriptions of past WIW columns & articles, I review my 1999 predictions and stick my neck out again with some SlowFly predictions for the year 2000. There is also a follow up/response to the high frequency speed controller discussion started last month http://www.ezonemag.com/articles/1999/dec/wiw/wiw1299.htm, a sneak look at my electric control line model, and of course, there are the obligatory updates of achievements from other SlowFlyers from around the globe.
Places to go & things to see
- J.M. Quetins home page from France (in English and French) - http://ourworld.compuserve.com/homepages/jmquetin/HomePe.htm lots of good stuff!
- the South Leicester Aeronutz have got a website up and running http://www.aeronutz.free-online.co.uk - lots of info for people interested in designing their own indoor scale aeroplanes both f/f and r/c, and some parkflyer info too. They'll be adding to it as their experience grows
- http://web2.airmail.net/sfrank69/expo/IRCFF.gif details of an upcoming indoor event
Thats all for a while now its your turn folks. Send me details of those sites you want the rest of us to look at!
Lets recall what I said 12 moths ago.
1998 the year that was
Before I jump into 1999, lets just have a very quick review of 1998.
From where I sit, I guess my impressions of last year may be summed up in one word growth !! The SlowFly scene attracted many new devotees in 1998, which can only be great for the future!
While more traditional flyers became SlowFlyers, the development of SlowFly never slowed down either. If you glance back through last years WIW columns, youll see that we collectively flew longer, slower, faster, smaller and more aerobatics (or should that be more adventurous) in more locations with more modelers. Helicopters and non-conventional layouts are a confirmed part of the SlowFly scene. Best of all, we now have more choices when it comes to where we choose to purchase our SlowFly goodies and the range of goodies is expanding all the time.
All Great Stuff I reckon!! WELL DONE all of you!!
1999 the year ahead
OK time to stick my neck out!?! Here are my predictions for the year ahead .
- All the growth in 1998 will continue in 1999. Growth will be slower in the more temperate climates and less populated areas where access to conventional flying sites is better, but where modelers have to travel some time/distance or contend with less hospitable flying climates, they will now look to SlowFly as a viable alternative.
- The types of SlowFly (and that includes "Park Flyers") models we fly will diversify to the point where we will start to develop rules (specifications?) for dedicated categories such as pylon, scale and aerobatics.
- Park Flyers will grow in popularity SlowFly development has already produced the technology and availability of suitable equipment. I can see groups of modelers gathering for "twilight" get togethers in local inner city parks after work, without upsetting the neighbours!!
- Where there are groups of SlowFlyers meeting regularly (lucky people!?), there will be a concentration and rapidity in the development of particular categories.
- The range of commercially available SlowFly products will expand as more manufacturers cater to the increasing demand. In particular, the range of motors/gearboxes & props, and servos/Rxs will expand.
- Battery development will continue there may not necessarily be more dedicated cells produced for us, but there will be an increase in the identification/adoption of current types and an expansion in the availability of those types. This will include, in particular, rechargeable cells other than Ni-cads.
- Battery expansion will be associated with and accompanied by an increased availability of suitable chargers, which will run from both AC and DC sources, to suite the indoor locations we fly in.
- SlowFly will move out of the novelty class and become an accepted part of mainstream R/C flying!!
1999 the year that was
This is easy just re-read what I wrote for 1998 but change the year! The whole SlowFly/ParkFly scene just keeps getting bigger and bigger. More devotees, more manufacturers, more suppliers, more web sites, more dedicated publications, etc., etc.
Now, how did I do with my predictions?
- enough said already
- Ive reported several events & sets of rules this year. There are no formal rules promulgated yet (do we really need any?) but I would hope personally that in the near future there will be a few simple standard events that will enable any of us to compare our performance with our fellow slowflyers anywhere around the globe, should we wish to.
- Just glance through the adds in any of the popular magazines and youll see a wealth of parkfly kits & ARFs.
- A bit obvious I guess, but as far as Im aware, its been happening. I know pylon racing or barn racing has been actively pursued by groups in Melbourne and Wollongong. What about the rest of you?
- As for No.4. For example, there are rxs now coming out of Canada, USA, Germany, Czechoslovakia, Taiwan & Japan.
- NiMh & Li. Ion cells have grown in popularity. Im currently awaiting a sample batch of NiMh cells custom manufactured for slowfly use to specifications we supplied something unheard off 2 or 3 years ago. Likewise, the Tadiran 450mah Li Ion cells were custom manufactured for WES Technics.
- Not as much development here as possibly in other areas. What I have seen rather than more dedicated chargers for small cells are more chargers with a wider range of fast (a relative term) charge rates that accommodate the use of smaller cells such as we use. Its still uncommon though to see a commercial charger in the lower half of the price range with charge rates below 500mah, or capable of safely fast charging several different cell types/chemistries.
- More and more of the traditional modeling magazines have introduced regular or semi-regular coverage of the slowfly/parkfly movement. They dont do it out of the goodness of their hearts! Its done to capture readership its what they believe their readers want to see.
2000 the year ahead
OK time to stick my neck out again!?! Here are some of my predictions for the year ahead .
- Most of my 99 predictions are still applicable, just bigger and better for the year 2000!!
- I think growth in ParkFly will overtake growth in SlowFly. I define SlowFly models as indoor models (typically under 200g mass & 5 - 8 watts of power. If it cant safely fly a flat figure eight inside a single basketball court, then its not really an indoor model!!). ParkFly models are bigger/heavier/more powerful than slowfly models (typically 200 700g and 10 70 watts)
- At the small/light end of the r/c equipment scale, I expect to see a move towards commercially available brick type radios such as were fashionable 25 years ago. Expect to see a rx., 2 servos and a 5 amp speed controller in the one sub 25g package.
- Indoor R/C events will become part of National championships in numerous countries around the globe.
- Watch out for brushless motor technology to hit the slowfly & parkfly scene and more ducted fan slowflyers
What do you think? Send me your predictions and Ill include them in the February column. Then we can review them this time next year.
Controller Update Part 2
Over the years of writing club newsletters and more recently, this column, I have only been reminded a few times of the fact that people are generally quicker to complain than to congratulate. Fortunately, the complaints dont come that often and in the absence of advice to the contrary, I can only assume that I am managing to present to you each month information of benefit/interest.
Unfortunately last month, in my attempts to promote discussion of some of the technology available to we SlowFlyers, I managed to inadvertently offend some of our fellow SlowFlyers. To date, I have never bothered with disclaimers, because I like to think that the readers of the E-Zone are smart enough to realize that the emails I publish are genuinely from fellow SlowFlyers, and not something that I or somebody else ghost writes to pad out the column.
In all honesty, I probably did foul up, in that I took the email/report on face value and didnt "verify" it with the other party referred to in the email Jean-Marie Piednoir. The author of last months email, Jacques Wakae jacques(at)vision.net.au has always been frank and open in my dealings with him, and as such I respect his opinions. Im also guilty of forgetting that you foreigners (i.e. Non-Australians) often have difficulty with the bluntness of we Aussies (an old school mate of mine referred to it as our ability to be brutally honest). Its not that we are blunt, but more that we are straight to the point if we have an opinion, then we state it and get on with our lives. I know this is the case with Jaques email it was his opinion, stated without embellishment. It WAS NOT my own opinion or that of the E-Zone. In an attempt to balance the discussion and continue to present you with the latest information, this month it's Jean-Maries turn to present his opinion (NOT MINE!!) on the benefits of high frequency controllers. What follows are the relevant excerpts from Jean-Maries emailed responses, presented to balance the discussion.
"Dear Mr. Hadkins,
My friends will tell you that I am normally a trusting and peaceful person. But, since it seems to imply that I agree with his views, I must react to your publishing Mr. Wakae's ridiculous letter in the December WIW. In my experience, Mr. Wakae's claim to fame relies on his hopping onto other people's innovations and either copying what he likes or knocking what he doesn't.
His Colibri ESC is a shamelessly obvious copy of my JMP7, down to the smallest construction detail and even the instruction sheet. When his first comments on my newly released 62 kHz HF9 ESC design appeared in the SFRC mailing list, I made the mistake of exchanging half a dozen mails with him on the subject of PWM generation. I stopped when I began doubting if it was him or I who had actually designed the HF9. (At the time, HF9 production prototypes had already been in test for ten months in my friends' models)
Let me put the statements in his letter straight :
In what at first seemed pure intellectual challenge, Mr. Wakae did suggest a way to increase my 62kHz to the theoretical limit of 66.7 kHz. Although clever, it was not practical in its initial shape. Building from this, I helped him refine this short piece of software to a workable state. I see no problem with our both using it.
As soon as I spotted a 4 Ampere claim for the HF9 in a U.S. ad, I contacted Wes Technik. They immediately asked their distributor to correct this obvious typo, as Mr. Wakae noticed.
The HF9 uses two microcontrollers. So what ? It is the simplest, smallest, lightest and, may I say, smartest solution, even if Mr. Wakae judges it some sort of sin.
Once you are told that the HF9 resolution is 16 steps, you will begin noticing it on the bench. If you fly the HF9, you won't (remember that a typical transmitter throttle stick has about 15 "clicks" from low to high ). In fact, praise has been made for the HF9 control smoothness. Figures aren't real life.
The HF9 uses FETs meant for direct microcontroller drive. They switch quickly and stay cool. Mr. Wakae's experiment with a 100 Ampere (Wow!) FET trying to pump 800 mA into a cored motor is completely irrelevant to the HF9 design. It is obvious that such a transistor, when driven by a CMOS gate, will switch at least ten times slower (large gate capacitance) and overheat quickly. As the (French) saying goes, there are situations when a small wiggly one is better than a big sleepy one.
Mr. Wakae questions the use of SO-8 package FETs. The FETs in the HF9 are not SO-8. Could it be that he never even had an HF9 in his hands ? That would be a fine way to make an opinion !
The HF9 has a higher internal resistance than common low frequency ESC's, due to the extra components required for high frequency operation. Again, so what ? Bench tests and flying experience (*) prove that the design objectives are met :
- Harmful current peaks in the collector of coreless motors are eliminated,
- System efficiency is noticeably improved (ESC + coreless motor),
- Size and weight are kept remarkably low (less than 2 gram including wires and connectors).
As a by-product, electrical noise is greatly reduced, making your receiver's life easier, all this in a happily balanced, practical and, in my view, elegant design.
Reflecting upon Mr. Wakae's letter, I feel I have been witness to a heavy spell of the NIH syndrome (Not Invented Here). Sorry to have used up so much space, I must now go back to real life.
check also: http://ourworld.compuserve.com/homepages/jmquetin/tips4e.htm#VariaHFe (which is a page from J.M Quetins site that I have reproduced here Wayne)
HF speed-controllers for coreless motors:
Coreless motors such as DC5-2.4, 1717, should not be used with ESC without any precaution. In fact, the internal inductance of these motors is too low for a good filtering of current peaks generated by the electronic switching of usual ESC with a switching frequency around 3 kHz. Peaks of 10 times the nominal current are possible, i.e. 10 A for a mean current of 1 A! As a result, the efficiency of the motor, the life duration of the brushes and even the capacity available from the battery will be reduced significantly.
In such cases motor manufacturers recommend to put in series with the motor a coil to improve the filtering. Unfortunately, these coils must have a quite high inductance value to be efficient and therefore have a big size and an high weight which are not compatible with indoor models.
There is another smarter solution: use a low inductance coil but increase its impedance by using an ESC with a high switching frequency. Indeed impedance is proportional to inductance but also to current frequency. So, a given coil with a 60 kHz current passing through will have the same impedance (and therefore the same efficiency) as a coil with an inductance value 20 times higher but with only a 3 kHz current.
It is now possible to find ESC using this principle on the indoor market. I have been trying for 6 months now a prototype device from JMP-France with a 60 kHz switching frequency. You will find hereafter a comparison table between standard and HF ESC performances:
WES 20X10 propeller
JMP 5 ESC
JMP HF9 ESC
As you can see, there is no benefit of using an HF ESC at full throttle (it's normal, by principle!) but at half or low throttle we can expect a flight duration 15 to 30% higher. In addition, and this is the most important, brushes and motor life duration should increase significantly. I suspect that Li-ion batteries will appreciate as well as they do not support current peaks!
Due to current limitation in the small coil, these HF ESC are only suitable for small motors such as DC5-2.4 or 1717.
I also subsequently received a lengthy email from Jacques which he did asked me not to publish. However, the following extracts are, I feel, very pertinent, and will, I hope, lay this whole matter to rest:
....The info I passed on to you was really for your information only and purely the result of some preliminary tests I did with various bits and pieces none of which were identical to the ones used in the HF9. I had at that time not laid an eye on an HF9 and was purely working on deductions made from JMP's early on statement of working on the development of a controller capable of over 60K in modulation. Actually all that intrigued me was the fact that he was modulating at such a very high frequency, that was all I had to base myself on.
Before he published a photo of an HF9 I had a working model of a 2-micro controller working already. My only interest was to prove the feasibility and to investigate the claimed improved performances. It has never been my intention to produce such a controller...... As I said before, my remarks on a high modulation speed controller were based on what I used and not on a HF9, I only saw one months later....
Please note I continue to have the utmost respect for both gentlemens technical abilities and achievements. I have several different types of Jean-Marie Piednoirs controllers and they all work very well. The HF9 is performing well in both my standard Kolibri and Mini-Kolibri - it doesnt get hot and the motor run definitely appears to be a little longer. I can and still do honestly recommend either gentlemens controllers to you.
There you have it. If I hadnt published Jaques email, none of you would be any the wiser (in any way!?!) If its any consolation, Ill be more wary in the future about which emails I publish. I will however, continue to be true to my Aussie heritage and remain eternally "direct and to the point" !!
Events you can run
As outlined in my coverage of our local SlowFly event in last months column, there were several events we ran that were simple and challenging, but also as it turned out, entertaining. The events were conceived to suite the venue, a local High School gym (single basketball court size).
Here are more details of the events we ran in Wagga and the results:
- Single slow lap around a rectangular course followed by a single fast lap around the same course, both from a flying start - the greatest time difference was the winner. 2 rounds were flown one with a left circuit and the other with a right circuit.
- Same course only this time, take off for a right circuit, fly right circles around the first 2 pylons then diagonally across to the last 2 pylons which are then circumnavigated in left circles then followed up by a landing in the centre circle of the basketball court fastest time wins. Repeat with opposite circuit direction.
WMAC - Indoor R/C Competition - Kooringal High School, Wagga.
Several of the photos from the report leaked out of the phone line between Australia and America so they didnt make it into last months report. Here they are:
Models at the first Wagga SlowFly Rally. Don Costelloe successfully flew the B2 inside the single basketball court sized hall twice. The transparent orange Kolibri is Greg Wilsons. Greg is still in the early solo stages with his outdoor greasy aeroplanes, but managed his first solo indoors without drama and repeated the feat several times during the Wagga event.
What else is happening out there in Internet land??
Another mixed bag of emails this month for your continued edification and consumption. There are follow-ups to some of the questions asked & answered last month as well as some more questions and some "hey world - look what Ive done" stuff. As always, I look forward to your emails it makes this column easier to write and I think more interesting for you. Remember all contributions gratefully accepted.
Here is this months selection:
First off comes a question from Robert Moore rmoore(at)softwaredecisions.co.uk regarding indoor flying in the South East of England. If any of our English slowflyers have information for Robert, please email him directly with a cc to me (Im trying to put together a list of regular slowfly gatherings/venues).
I live in Kent England and commute to London during the week giving me access to most of the South East. Is there no where to do indoor flying in this area? No clubs or anything? The only contact I have found is a Club in Tonbridge, Kent that specializes in free flight and gives over their facilities at 9.30pm till 10.00pm, once a month to RC flyers.
There must be people in this area with interests in slow fly and indoor flying, I hope. I am new to this branch of RC modeling and building my first model at the moment.
If you know any contacts please let me know.
Robert Moore (Consultant)
My advice on NiMH cells produced some feedback from Neal Friedman <nealf(at)isdl.ee.washington.edu>
A clarification on NiMH vs. NiCd charging.
Nicad chargers look for the voltage to peak and then *decrease*. NiMH chargers look for the voltage slope to increase and *level out*. If you charge NiMH batteries and wait for the negative slope you've overcharged the battery, and possibly damaged it.
Unless the charger was specifically designed for NiMH batteries, it likely uses the NiCd charge profile and looks for "negative delta V". However, that mode of operation is specifically *not* OK for NiMH batteries.
An alternate method, usable for either battery type is to monitor cell temperature and stop when the temperature reaches a threshold or exceeds a slope. If your battery gets really warm - STOP. If you have a cell phone or shop tool battery pack with 3 wires instead of 2 - the 3rd is probably a thermal sensor.
Mike Ladwig mike(at)twinpeaks.prc.com has some Kolibri questions. They keep coming in and Ill keep answering them because I think its a great little aeroplane everybody should have one in the cupboard!
Hi. I've been trying to track through all the various 'Kolibri' plans and discussion, and only have a couple of questions...unfortunately, very basic questions...
- What electronics (receiver/servos) are reasonable?
- In terms of flying skill level, how does the kolibri compare to other slowflyers?
- I've never tried to build a carbon rod -based model before how difficult is it to do for a balsa guy to jump into?
Ok Mike, to answer your questions:
- Any Rx under 20 g, 2 servos under 10 g and a speed controller with BEC under 15g. The Kolibri will fly with an all up weight of 135 140 g but I recommend 120 g as a maximum mass.
- Very similar its slow yet responsive, bounces VERY well off walls etc due to its all carbon construction. Newcomers often need help setting up the v-tail correctly. It is an ideal indoor entry level airplane.
- Very simple. Wear eye protection in case a carbon rod slips out of your hand while your bending it they spring VERY quickly. You assemble rather than build the model it should take you 3 to 4 hours.
Alexander Van de Rostyne alex(at)staf.planetinternet.be has been doing some fixed wing flying and sent in this report on his experiments with knife edge flight. I look forward to seeing the pictures Alexander!!
This is a bit outside my normal helicopter activities. Years ago I was flying mainly pattern planes (F3A as they call it). This summer, the bug of designing an indoor pattern plane hit me....There are of course lots of indoor planes that can roll and loop, but performing a graceful pattern flight is something that at least I have not seen yet.
The plane I developed is a 4 channel mainly depron plane with elliptical wings. Motor is the eternal 1717. Batteries 11 cell 50mAh or 120mAh. It can turn absolutely flat turns within a 2-3 meter diameter, stall turns, rolls and so on. The current hall I fly in has a very low ceiling, so I have not fully exploited vertical performance yet.
But it does a full straight knife edge flight (with not more that 1 meter between the low wing tip and the floor) at half throttle for as long the hall length lets you do it. If I had more headroom, I bet it could do a knife-edge loop. With some more stick time, I believe I can squeeze a 540 degrees stall turn out of it...(yes, like a helicopter).
I will get you some pictures as soon as I can. There are some interesting design concepts. Current weight is 160 grams, but further releases should bring that down to the 130 grams mark.
Stop the Press!
This column had been off to Steve for over 24 hours when I received a phone call from Don Costelloe detailing his "millennium flight". Don backed it up with an email an hour later - I thought the 'achievement' justified rushing it in as a "stop press" for the January column. Unless a 'Kiwi' (sorry, a New Zealander) can prove they were night flying at midnight their time, I think Don's flight can justifiably be considered the first R/C flight of the millennium, and it was done with a Kolibri folks!!
Happy new year to you and Gabrielle. Just a short note to tell you of our New Year's feat. Maybe we are the first in the new millennium to fly RC. At approx. 00:03:43 on 01/01/00 we launched the Kolibri in the cul-de-sac in front of my house and flew for 3 to 4 minutes using little cylume sticks to light the plane. There was a very light breeze so it was a bit tricky but the landing was smooth and safe. Andrew Goddard acted as camera man and video is following in the mail on Tuesday (with your cafe' bar cup wheels). Until then smooth flying, don't let that gravity pull you down.
Well done Don. Not only did we have the best New Year's fireworks (off the Sydney Harbour bridge), we had the first R/C flight. (And Yes, I do know that 'technically' the new millennium doesn't happen until Jan. 1st 2001, but 2000 is commonly accepted as being 'it' so who am I to argue??)
I have mentioned several times that I have been plodding away on an electric control line model. Well, I finally finished it over the holidays, and guess what it flies!! Ill have full details next month, but in the meantime, here are some pictures to get you thinking.
A sneak peak" at my electric control line model, a Piper Cruiser. Power is an 05 with 3:1 belt reduction unit. Mass is approximately 2 lb. with 7 x 1700 cells. More details next month
I know its not SlowFly, but it sure is ParkFly!! Mind you, if I find a hall big enough (35 foot lines), Ill give it a go!
Dont forget to email me. whadkins(at)ezonemag.com with all the SlowFly happenings in your part of the world.
As I put the finishing touches to this months effort, Im watching the fireworks in Sydney on the TV the clock has just ticked over to the year 2000. Have a GREAT New Year folks I wish you all peace and prosperity.
Well folks, thats your SlowFly lot for this month - Thank you for joining me in another mystery tour of Waynes Indoor World. In the mean time, wherever you may be on this SlowFly planet of ours, enjoy the new year, do it low and slow, and most of all, HAVE FUN!!
See you all again next month - Take care friends.
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|Category||Thread||Thread Starter||Forum||Replies||Last Post|
|Article||Wayne's Indoor World - December 2000||Wayne Hadkins||Electric Plane Talk||0||Dec 19, 2000 12:00 AM|
|Article||Wayne's Indoor World - October 2000||Wayne Hadkins||Electric Plane Talk||0||Oct 13, 2000 12:00 AM|
|Article||Wayne's Indoor World - September 2000||Wayne Hadkins||Electric Plane Talk||0||Sep 13, 2000 12:00 AM|
|Article||Wayne's Indoor World - August 2000||Wayne Hadkins||Electric Plane Talk||0||Aug 16, 2000 12:00 AM|
|Article||Wayne's Indoor World - June 2000||Wayne Hadkins||Electric Plane Talk||0||Jun 13, 2000 12:00 AM|