ELECTRIC FLIGHT U.K. ISSUE No. 86 AUTUMN 2006 THE MAGAZINE OF THE BRITISH ELECTRIC FLIGHT ASSOCIATION

Transcription

1 ELECTRIC FLIGHT U.K. ISSUE No. 86 AUTUMN 2006 THE MAGAZINE OF THE BRITISH ELECTRIC FLIGHT ASSOCIATION

2 THE HOME OF... Discussion forums FREE Areas for all types of glider, electric, fuel planes plus car and boat modelers Galleries of hobby photos from modelers all over the world E-Flight mailing list thousands of members world wide! Classified ads Three Separate In-depth Webzines EZonemag.com - rcpowermag.com - liftzone.com Regular columns and HOT NEW PRODUCT reviews in all areas of RC YEARS of articles archived

3 Electric Flight - U.K. Issue 86 - Autumn 2006 "To Encourage and Further all Aspects of Electric Model Flight in the British Isles and Elsewhere" - B.E.F.A. Constitution CONTENTS BEFA Committee 2005/ Chairman's Chatter... 5 Current Lines... 5 How it started... 6 Southern Model Air Show...15 A memorial Conversion LiPo deterioration...20 New-2-U...24 Indoor R/C Flying 2006/ TLC from your TLO PANDAS...36 NiMH Recovery Jeti Advance Plus Programme Card Electric Flight Calendar For Sale / Wanted...50 Wanted by the Editor...52 New to Electric Flight? Start Here...53 BEFA Sales Advertisers Index...54 Cover Photo: The cover photo is Bill Jackson showing off his pampered jet which is featured in his article How It Started The Need for Speed and Looks (Part 2) which you will find on page 6 with additional photographs on the colour centre pages. Next Issue: The copy date for the Winter 2006 issue is 20 November 2006, with the magazine due for publication by 23 December DISCLAIMER B.E.F.A. and Electric Flight U.K. wish to point out that the content, techniques and opinions expressed in this magazine are those of the individual authors and do not necessarily represent the views of either the Editor of this magazine or B.E.F.A. and its committee. All information in this magazine is copyright of the authors. Any request to use information from this magazine is to be made to the editor (contact details overleaf). All reasonable care is taken in the preparation and compilation of the magazine, but B.E.F.A. and its committee cannot be held liable for any error or omission in the content of this magazine or any subsequent damage or loss arising howsoever caused. To allow proper appreciation of the photographs used, colour copies of them will be posted on the B.E.F.A. website after publication of this magazine. If you can, check them out at E.F.-U.K. 3

4 BEFA Committee 2006/7 Chairman Robert Mahoney 123 Lane End Road, High Wycombe, Bucks. HP12 4HF Secretary Jan Bassett Webmaster 111 Plantagenet Chase, Yeovil, Somers. BA20 2PR South West Representative Tel or Treasurer Bob Smith Membership Secretary 1 Lynwood Avenue, Tollesby, Middlesborough, Cleveland. TS5 7PD Northern Representative bob.smith007@ntlworld.com EF-UK Editor Jill Day 6 Starboard Walk, Littlehampton, West Sussex, BN17 6QL editor@befa.ef-uk.net Events Co-ordinator Terry Stuckey 31 Dysart Avenue, Kingston-upon-Thames, Surrey. KT2 5QZ terrystuckey@blueyonder.co.uk Competition Secretary David Perrett 10 High Lees, Sharnford, Leicester. LE10 3PW Tel: d.l.perrett@btinternet.com Midlands Representative Roger Winsor 14 Butler Gardens, Market Harborough, Leics. LE16 9LY Rogerwinsor7@aol.com Welfare Officer Dave Chinery Southern Representative 251 Station Road, Hayes, Middx. UB3 4JD DavidDchinery@aol.com Indoor & Free-Flight Rep. Gordon Tarling 87 Cowley Mill Road, Uxbridge, Middx. UB8 2QD gordon.tarling@ntlworld.com Technical Liaison Officer Alan Bedingham 17 Highcliffe Close, Wickford, Essex. SS11 8JZ bbba18333@blueyonder.co.uk Public Relations Officer John Thompson 19 Park Avenue, Liversedge, West Yorks, WF15 7EQ Tel johnty99@ntlworld.com Safety Adviser David Beavor 34 Chestnut Close, Brampton, Huntingdon, Cambs., PE28 4TP. Please enclose an SAE with all correspondence to the committee. 4 E.F.-U.K.

5 Welcome to issue No 86 of Electric Flight UK This year s flying season seems to have flown by again. I am in the process of booking our premier event at Middle Wallop; I then noticed that the Saturday will be the last day of June. So it would be a good time to put the dates in your 2007 diary so you don t miss this great electric event! I have just returned from Aspach event near Stuttgart, the safety at this event was worse than when Gordon Tarling and I attended in I was one of the persons who were shot down! It seems that the organizers are letting mobile phones / handys pass the flight line and up to the pilot s box! I was asked when booking my transmitter what channel I was using! But this was not checked with a scanner in case I had made a mistake. This is against ours and the BMFA / CAA s recommendation for a safe event, especially as there are thousands of public I hope very much that you enjoy this edition of your magazine, which as you are all aware, is my first crack at it! I am sure you would all like to thank your previous Editor, Jan Bassett, for his sterling work on the magazine and I will endeavour to keep up his high standard. I would personally like to thank him for all the support he has given me over the last few weeks, and hopefully in the future, with all the technical stuff it s all a bit of a mystery to me. I would also especially like to thank all the contributors for this particular edition of Electric Flight UK, for their support and patience, which has been tremendous. Chairman s Chatter attending this event. I did leave the organisers a copy of the BMFA handbook and the updated CAP 658 from the CAA; you should have seen their faces when they started to read them! The Danish flyers asked for a copy of the CAP 658 because one of them was not happy at the amount of flyers that had problems. I will try and write an article with photos for the next issue of EFUK. It s now the time to think of obtaining tickets for the TWS in November, there are more details of how to get there in this issue! Well that s all for now so keep it safe. Keep the watts up Robert Mahoney Current Lines This is your magazine and I cannot produce anything without all your contributions, both the written word and photographs. Don t worry if you have never written anything before, have a go, what you are interested in and enjoy, others will as well...and it will keep me very happy! Jill Day Editor E.F.-U.K. 5

6 Readers Models Your chance to show the members your model(s). How It Started The Need for Speed and Looks (Part 2) by Bill Jackson NOTE: See Electric Flight U.K. magazine issue No. 81 Summer 2005 for Part 1 Childhood Wonder My first recollection of liking aircraft was when I was about 10 years old. My mother used to take me to Romford market, Essex, in the late forties and early fifties when it was a farmers market with livestock. In contrast to the rustic charm of the olde worlde market place, just yards away in North Street was an outpost of modernity (to me at the time!) in the form of a model shop. When I first discovered the stockpile of wondrous things within the shop, my world took on a new vista of interest. The focus of my attention was a small scale static model of the MIG 15, produced I believe from a Keil Kraft solid balsa kit. This was placed prominently in the front window of the shop, resplendent in its aluminium livery with bright red trim. The builder had produced a magnificent job of detail, finish and realism, down to the pilot and cockpit controls. Apart from its technical appeal like a steam engine in the South Kensington Museum, it had aesthetic appeal of beauty and grace like a Cezanne painting. I was sold on aircraft, especially jets, from that time onwards. Foibles of Youth Soon after this I started building small rubber powered flying models and was pleased with their performance. My introduction to jets was scratch-built models powered by Jetex, but with not much success I had yet to learn about the importance of correct centre of gravity position and motor thrust angle! More success was achieved when I mounted the Jetex unit in a small speedboat and tried it out in our large cast iron bath at home. I discovered that the unit worked just as well upside down in the water as in air. My father said that the resulting smoke that filled the bathroom resembled the smell of cordite from the heavy anti-aircraft gun he operated in the war. He then went on to illustrate briefly what world war was like: he was not happy. I learnt to keep future experiments well away from the house. The next stage was o**y f*n (mostly diesel) powered control line models. My free-flight club mates used to call them bricks on strings, but I was impressed when I was timed at 91 mph with a 1.5 cc Taiphun Hurricane powered speed model. 6 E.F.-U.K.

7 I felt that I had arrived, but like reggae star Jimmy Cliff sang, There are many rivers to cross, or in our case, there are many skies to fly! I think my disenchantment with model I.C. engines started when my next even faster speed model, powered by an Elfin 2.5 cc diesel converted to glow, suffered from catching fire. I called it Phoenix, but (unlike its namesake) it eventually never rose from the ashes. On its last memorable flight, equipped with a full tank, it authoritatively took off from its dolly and put in a blistering performance (literally). However, by the time I was able to land it, there was not much left. About this time, a few modellers started using the early forms of radio control, one of which was affectionately (or not so affectionately) known as Galloping Ghost. It was soon after this that aviation was put aside for other later teenage pursuits such as motorbikes and studying. There was to be a return, in an unexpected way, years later. Oily Information I believe the person who had made the Elfin motor conversion had not paid sufficient attention to the compression ratio; it was too high and caused less than optimum performance with flames sometimes coming out the exhaust ports. Compression ignition engines such as diesels (or other oil burners) rely on the heat generated by the fuel/air mixture being highly compressed to cause spontaneous combustion without a glow or spark plug being involved. Model glow motors and car petrol engines, however, use a much more volatile fuel and rely on the auxiliary ignition providers to keep running. If the compression is too high for the fuel being used, or the engine is not in good condition, the engine will act like a diesel and combustion will be more a detonation, rather than rapid burning, with consequential rough running (known as knocking or pinking) and probable consequential damage. There you have it, the oily horror details. Sorry to inflict you with this in a clean electric magazine, but to appreciate the good we sometimes have to know about the less than good. I know the little story of Phoenix is not a common happening. Probably, Alfumaso Motorfanoilio (that woke the spell checker up) will write back and inform me how reliable and sophisticated the internal combustion engine is with the latest refined electronic ignition, fuel injection and computer engine management systems. Yes the I.C. engine has served us well for over a century and come a long way in that time. However, we are now fortunate to have many choices, especially in our hobby, on the means of propulsion we can use. I believe the electric way is the most efficient and convenient way. We can now see small electric ducted fan models flying faster than some gas turbine powered jets at a fraction of the cost and paraphernalia. E.F.-U.K. 7

8 Electric motors and ancillary products like batteries and motor speed controllers, suitable for model aircraft, have only become generally commercially available in the last 25 years. I am amazed at the progress made in that time and the wide range of quality products now available at a reasonable price. The attraction for me is how much power can be delivered from such a small size unit as a 400 brushless motor. Bill steps down off his soapbox and continues to talk (mostly) about electric flight Return to the Fold In late 1979, many years after flying control line models, I was walking with my family alongside the local heath when my wife brought my attention to the presence of radio control gliders high in the autumn sky. You used to fly model aircraft like that, didn t you, she remarked, and added Wouldn t you like to take it up again? She didn t have to say it twice, I started paying attention when I heard the words model aircraft after some talk about decorating and new curtains. However, I had to wait to the next day for the local model shop to open. My training with fully proportional radio control equipment went fairly smoothly on an I.C. powered trainer. I then bought a Phoenix (100 inch span) glider which was a popular type at that time. This was a clean and pleasant change from noisy power planes tearing about the sky, but not entirely without its own particular problems. My heath is fairly accessible to the general public and I found that the bungee launch system, of several hundred feet of nylon fishing line and bungee rubber, seemed to attract young motorcyclists, horse riders and oblivious lovers. It seemed they were all eager to frequently get wound up in my bungee. I persevered with this situation for some time, but the last straw came one day when I thought that I had the field to myself. I bungeed off and gained a good bit of height, I saw the glider twitch as it sniffed out a thermal. Looks like it s going to be a good flight, I thought. It was at this point that I noticed that the orange day-glow parachute, attached to the end of the bungee, had landed and was continuing to move away from me along the grass. Funny, I thought as I observed that the wind was neither in the appropriate direction nor strong enough to have this effect. I landed as quickly as I could as I sensed that something was seriously wrong. Looking towards the parachute I noticed on the far side of the field a person to whom the parachute was heading. Funny, I thought again, not knowing what was happening. I ran after the person, and as I got near I realized the situation. The elderly lady had seen my goat tethering hook in the ground (unknown at first to her, anchoring the far end of my bungee) and with Superwoman strength had pulled it out. The hook had taken all my strength to push it in! She was in the act of trying to stuff several hundred feet of fishing line and 8 E.F.-U.K.

9 bungee into her shopping bag as I caught up with her. Please can I have my bungee back, I cautiously requested of the lady, but she was very reluctant to give it up. I believe she thought that it had been used to tether some gypsy s escaped horse and she didn t want to give up her precious acquisition to me. I suspected that if I hadn t convinced her it was mine she seemed determined enough to fight me off with my own tethering hook. A vision of biblical Samson slaying the Philistine army single-handedly with the jaw bone of an ass jumped into my mind. I walked off the field disappointed, wondering why I couldn t enjoy my flying without some external problem. Introduction to Electric Flying Soon after this, my local club had an auction and I bought a Humbrol polystyrene ARTF power assisted glider kit (approx.1m span). This free-flight model came complete with a little electric motor and a single AA size NiCd, all for the knock-down price of 12. I knew this would be ideal for the heath, after the problems I had with bungeeing large gliders and the by-laws restricting I.C. powered flying. I was disappointed at first by the lack of power, some flights lasting no more than ten seconds. Eventually, I discovered, that if I was patient and kept recharging (direct from a large bell-battery), soon after each flight, the NiCd became more energetic and the flights became longer as more altitude was reached. The single NiCd seemed to thrive on this treatment. Flights continued to improve all the time as I learnt to trim the model for the optimum according to the day s conditions. Even though the model was small and not radio-controlled I enjoyed watching it fly. It had character and charm in spite of its simplicity; I fell in love with electric flight at this point! However, little Humbrol electric was not to be with me for much longer. After several weeks of being my frequent friend, on a warm sunny morning it left my hand on its last launch. It circled three times overhead, as if to say cheerio to me and the heath, gaining height all the time. It then straightened out and headed south east towards the rising sun. Humbrol had come of age and was out to discover the world... or the Thames Estuary at least. I never saw it again. In addition to the pleasure the model had given me, it made me realise the potential that I had on my own doorstep. The heath could be my private flying field without the other problems I had encountered previously, if I flew radiocontrol electric. At that time (early eighties), I knew of only two other people in my club, of about 50 members, that were interested in flying electric. Not to be deterred, I collected all the information I could to enable me to build something that would fly convincingly and be a good example to the o**y f*n flyers in my club. E.F.-U.K. 9

10 On rare occasions, the model magazines would publish the odd plan of an electric plane. It was only when I discovered the article in the Radio Modeller on the Voltaire that I felt that here was an aircraft that would be taken seriously. Also, I could obtain a suitable motor and battery pack that would do it justice, without breaking the bank. Voltaire (owner unknown) (see picture below) My resulting Voltaire was powered by a standard Mabuchi 540 and a 8 cell pack of Saft 1200 mah sub C NiCds.*In terms of today s electric exotica, it was a very basic power system. However, together with a dedicated and well thought out airframe, it was as good as you could get for the performance, money and simplicity. Voltaire was a major contribution to the way forward for electric flight, and it could do good aerobatics albeit limited by lack of rudder. One had to be careful when flying slow or on a landing approach as it had (or mine did) a tendency to tip stall. *NOTE: With a small increase in weight and size, at time of writing, sub C NiMH of 4300 mah capacity can now be obtained. This is a capacity increase of about 400%, a tribute to the evolving technology. There have been a lot of skies flown since Voltaire, including being introduced to slope soaring, another enjoyable facet of our hobby. Since then, I have increased my electric building and wound 10 Bill s modified Voltaire E.F.-U.K.

11 down I.C. For over three years I have not built nor flown an I.C. powered plane of my own. Also, I have disposed of nearly all my o**ly f*n bits. Electric flying refreshes the parts that castor oil cannot reach. I know, I m preaching to the converted, so let s get back to flying! modification gave superior performance and appearance to Mk 1, bringing the Pampered Jet alive. (see picture below) However, after about 30 enjoyable sprightly flights the performance started to drop off, until eventually the plane sunk to the ground and could fly no more. Return to Pampered Jet My previous article described my Pampered Jet (1067mm span), a far-off scale Pampa Jet. This had been converted from an externally fitted WeMoTec Mini Fan 480 and Plettenberg motor by grafting on part of a Wattage F86 Sabre fuselage with the original Wattage fan unit and 400 size brushed motor still fitted. This I had unwittingly flown the poor little Wattage 400 motor to death. In its willingness to supply full performance without complaint I had overlooked its limitations. It had given its all until the end, without any of the usual visible signs of distress such as the spread of the Black Death (carbon dust from the breakdown of the brushes and commutator, a motor s costly equivalent of letting out the smoke from a speed controller). Pampered Jet Mk 2 E.F.-U.K. 11

12 This situation reminded me of a popular set up, amongst the early electric jet jockeys, of a Speed 480 Race motor in a Mini Fan. This reportedly gave good performance from an economical and readily available set-up. However, there were tales of brushes lasting only 20 flights if you took liberties with the available power. defence council informing me off mitigating circumstances regarding your efforts to push back the frontiers of science and technology, and fly on the edge ( Do what? I just felt the need for speed your honour, Bill thinking), I am giving you a suspended sentence provided you agree to showing more consideration for your last remaining brushed motors. The Trial I can hear the Model Aircraft Judge in his summing up at my trial: You have shown a blatant disregard for the well-being of your own motor. Your sentence would have been to spend the rest of your life flying with oily fan engines. However, owing to your I nodded sheepishly in response and left the court a free man, heading for the open space of the flying field, my Joint Strike Fighter (brushless fitted) in one hand and my transmitter in the other Statement to the Press In my defence, I had been lulled into a false sense of security by Percy, a builtup propeller-driven flying wing, powered Pampered Jet s hatch 12 E.F.-U.K.

13 by a rear-mounted Speed 400 6V and an 8- cell pack of GP 1100 NiMH. This had given me hundreds of enjoyable and reliable sprightly flights. I had underestimated the extra work-load that a similar motor (as I thought) endured in a ducted fan unit. Its willingness to give good performance, that I exploited, belied the effect this was having on its longevity. I was expecting too much. I am sorry for any inconvenience caused. My wife is supporting me in this matter as I have promised not to waste the housekeeping money in future. (see top picture page 28) In place of the Wattage fan unit and deceased motor, I decided to fit a Mega 16/15/2 brushless motor and Mini Fan borrowed from another model. This had necessitated cutting a hatch in the bottom rear part of the foam fuselage to enable removal of the Wattage fan and motor. I had to relieve the inside of the fuselage and hatch to accommodate the increased diameter (by about 5mm) of the new fan, and blend the result to make a smooth transition into the remaining tail tube. I used a large diameter round file and finished off with smooth sandpaper. (see photo page 12) I then tacked the fan unit, with motor fitted, into the top part of the fuselage using a little 5 minute epoxy on the mounting flanges. This was to hold the assembly in the correct alignment position for the next stage. White PVA glue was then used to secure the hatch to the fuselage. Micro balloons filler was used to fill minor indentations at the joins, and a few strips of solar film, were applied. This quickly made a semi-permanent mounting for the fan assembly that was simple, hardly detectable and strong. It only requires a sharp knife to effect future access without major hacking. NOTE: If you can afford the long drying time, PVA is an excellent glue to use with polystyrene foam and is a good gap filler (do remember to wipe off the excess before it dries). The result is lighter than epoxy and more resilient than foamfriendly cyanolate. The Mega 16/15/2 motor and Mini Fan in the previous model had been powered by 8x1950 FAUP NiMH with a Jeti 40 speed controller, and took about 32A max. I invested in a Flightpower 3s1p pack of EVO mAh LiPos and borrowed a Jeti 70 Opto to cope with the extra power (estimated to take about 46A). These fitted nicely in the plane without any surgery, and the original position of the C of G is retained. (see bottom picture page 28) Mk 3 Pampered Jet, thus newly equipped (wing loading had increased from 13.8 to 16.4 oz/ft²), was hand launched in the normal way (keeping previous trims). Instead of taking up the usual climb angle of about 15 degrees with mild acceleration, it pulled away from my hand and accelerated with vigour at a climb angle of about 45 degrees no bungee required here! It only took seconds to reach a height of several hundred feet. E.F.-U.K. 13

14 I split S to bring it back down towards me, still accelerating as it whizzed past my left ear at a speed far in excess of anything before. The flight envelope was explored with a few rolls and loops, as well as flying slow to see if anything had changed. I was pleased to find the handling was just as sweet, a bit better if anything, as it had more authority in manoeuvres with the extra power available. Landings were just as gentle. I was very happy; Pampered Jet had retained its personality but had gained more presence (and of course speed). I had fulfilled my ambition, dreamt about decades before, of building a fast model jet with (enclosed) ducted fan propulsion. Like the little MIG 15, sitting in the window in the shop in Romford many years ago, Pampered Jet has the same sort of beauty and grace, but my plane can fly with scale performance. That reminds me, I need to consider my next project. I rather like the look of that Alpha MIG 15, it s beautiful and if I can stretch to a Mega 16/7/4 motor and Lipos, it would really go. It s my birthday soon, I wonder what the wife is getting me I hope it isn t wallpaper for my model room! Bill Jackson 14 E.F.-U.K.

15 Southern Model Air Show Presented by Croydon Model Flying Club The Hop Farm, Paddock Wood, Kent Sunday 17th September was a beautiful and balmy late summer s day even at the crack of dawn. It certainly felt like the crack of dawn as I ventured forth to accompany my husband Keith to the Southern Model Air Show. Why, you may well ask because I am a dutiful wife! However, by the end of the day my belief of what the day that stretched ahead was to be like for me certainly changed. The journey was easy because of course there was no traffic at that time of the morning on a Sunday. Consequently, we were amongst the early birds who were also arriving, by this time it was about by Jill Day 9am, which ensured the parking was hassle-free. Always a good sign when the day begins well and certainly this boded well for our day ahead. As a bonus, The Hop Farm which can be visited at was an excellent choice of venues for the show, with loads of character and plenty of stuff to see which would encourage making the day a family occasion. The setting for the flying displays was a huge open space with a background of trees. This made an excellent stage for boys as young as 12 years, to men up to well a great deal older, to display their planes and demonstrate their remarkable skills, which even I could appreciate, and which was a joy to watch. One of the younger Electric Flyers Photo: Keith Day E.F.-U.K. 15

16 One of the stands dedicated to Electric Flight Some of the country s top pilots were at the show demonstrating all types of models from Vintage Scale Biplanes to the latest Turbine Powered Jets and helicopters, all very exciting. The model flying displays were absolutely thrilling and some were fun as well. For instance, trying to burst balloons in the air and on the ground, and attacking toilet paper with the aim of ripping it in half! This was along with a spectacular Warbirds pyrotechnic display which was enjoyed enormously by the crowd. There was a slot each day dedicated to electric flight plus electric helicopters in Photo: Keith Day the helicopter slot. I m afraid I can t tell you all the things you are longing to know about the planes because unfortunately I do not have the knowledge, all I can do is give you a flavour of the day. In fact, it was a very exciting day, with lots to see and experience, even a radio control flying lesson for novices during the lunch break. Plus two absolutely wonderful Aerobatic displays with full size planes, a Sukhoi 26M, piloted by Will Curtis and an Extra 300L piloted by Paul Fellows. Again, both much enjoyed by the spectators and there was more! E.F.-U.K. Photo: Keith Day

17 Above:...and then there were the Electric Helicopters Below:...and a familiar name Photo: Keith Day Photo: Keith Day There were also various commercial stands from companies selling their merchandise, with some products being sold at special show prices. Even if you didn t want to buy anything it was a good opportunity to rummage round the stands to see if there actually were any must haves or can t live without stuff to buy. So there you have it, I went to keep Keith company and ended up having a jolly good time and looking forward to next year! We took a few photographs just to give those who weren t lucky enough to be there some idea of what they missed. Jill Day (see photos page 27) E.F.-U.K. 17

18 A MEMORIAL CONVERSION My first meeting with Arthur Fox was when radio control was in its infancy and he astounded us by walking on to a playing field in Nottingham and test gliding a large model. Many years later he came on to the BMFA Stand at Doncaster Racecourse and we got talking. He had in the meantime gained a reputation for designing and building unusual models, mostly Vintage style, and won many awards for them. Our talks got round to my other hobby, the Northern Aeroplane Workshops where we are building a full size Camel from original drawings. Many of you will be aware of the Sopwith Tripe and Bristol M1C made by the NAW and now flying regularly at Old Warden. We are based at the Yorkshire Motor Museum on Bradford Road, Batley, West Yorkshire, and Arthur was kind enough to donate several of his models to be displayed there. Unfortunately Arthur died earlier this year and I asked permission of his sons to be allowed to convert one of his models to electric power and fly it at some of the shows in his memory. His later models had been electrics, and it was suggested that the twice size Ladybird would be the most suitable. The original of course being a semi-scale free flight model kit by Keil Kraft for a 1cc diesel. His plan of this 84" span model was featured in RCM&E just twenty years ago, powered by an OS40 four stroke, and the model showed signs of a lot of air time. by John Thompson In my workshop was a spare 600watt outrunner motor which could swing a 13" prop and would be lost in the radial cowling. The top half of the cowl conveniently hinges up, giving ideal access, so the motor was installed with a simple alloy bracket and the Jeti controller Velroed neatly in the bottom. This left space above for a battery pack to be slid into a ply tray, so the only change was a hole for this in the firewall. Although most of my batteries are LiPos they would be too light for the CG, so a pack of 14x4/5sub C Panasonic NiMh was installed in a ply tray. These seemed to give enough waft but I was a little concerned with the 40amps! Two servos on Rudder/Elevator and a RX battery with state indicator were lost in the capacious fuselage. Down at the beautifully mown Dewsbury field with a gentle breeze she lifted off in fine style. However, it had an objection to turning right and caused some heart stopping moments trying to get it down. This was eventually diagnosed as wear in the complex rudder linkage inside the fin causing blowback. Not wanting to dig into the structure a simple solution was an unobtrusive closed loop system which works perfectly. I took it to Chester where it attracted a lot of attention, but was unable to fly due to the turbulent conditions. A card was attached to announce that it was there in memory of Arthur. Many claimed to have built the original KK one and an Irishman was ecstatic as he had two of the bigger ones. 18 E.F.-U.K.

19 Many pictures were taken. The first public flight was at the York Club s Ebor event and the first flight was perfect, slow and graceful, with a certain presence in the air. The next one was not so good and it seemed the cells were objecting to the high current. However, Mike Proctor and the team were kind enough to award it First in Sport, thanks lads. Back home a pack of 3,000 cells was made up from some that the American Team were selling off at the World Champs in These would stand the amps with no problem and the weight was still just under 8lbs all up. This was a lot better and at our Pontefract meet two flights were made, although I must admit my rudder elevator flying leaves a lot to be desired. Arthur s models at the Museum include, 1933 Hobbies Monoplane, Bishops Endeavour (now that is a beast), At Ease, Fillon s Champion, Lanzio Record Breaker, and Bower s Duck, so if you are at a loose end one Sunday morning we are usually there, drop in for a chat. Incidentally any payment from this article will go to the Northern Aeroplane Workshops funds. Also, we can usually provide a speaker for Club talks within reasonable distance of Leeds, Wakefield, and Huddersfield. Many thanks to Bill Macleod for taking the flying shots with my camera at the PANDAS event. John A Thompson Chairman, BMFA Northern Area johnty99@ntlworld.com E.F.-U.K. 19

20 LiPo deterioration by Bob Smith The majority of electric flyers who use LiPo battery packs are well aware of the pros and cons of their use. It is the cons which tend to be of greatest concern but in my opinion, the difficulty is simply that we have not been using LiPo packs long enough to have determined exactly what is best practice in this area, and the majority of problems stem from this fact. We are improving our procedures continuously and if we allow for the improvements that manufacturers (of both cells and ancillary equipment such as chargers) are constantly introducing, then our difficulties will reduce significantly over the next couple of years. Use of four DVMs to measure individual cell voltages 20 E.F.-U.K.

21 I am not referring to the kind of catastrophic failures, which do occasionally happen but to the deterioration which occurs progressively with the use of the pack and which unfortunately seems to be irreversible. This is compounded by the fact that, at the moment, it seems to happen far sooner than we might hope. I recently had an opportunity to look into one particular aspect of this problem, and was surprised by my findings, but at least I now know what to look for in the future. Let s start by looking at balancing as we have come to know it. This is a process intended to make sure that a set of cells in a series pack are kept in ideal condition by keeping the individual cell voltages identical (or as near to that as we can manage) during the re-charging procedure. The need to follow such a procedure stems from the critical nature of the maximum cell voltage during charge. To obtain maximum capacity in a LiPo cell we must charge at a rate of 1C (e.g. 2.4 amps for a 2400 mah cell) until the voltage reaches but does not exceed, 4.2 volts. Exceeding this value, even by relatively small amounts, can damage the cell. In a series pack, it is possible to damage one or more cells if we only control the total voltage. As an example, a charger might charge a 4S pack to 16.8 volts (4 x 4.2) but if the individual cell voltages are not measured and controlled this could be the summation of 3 cells at 4.1 volts and 1 cell at 4.5 volts, resulting in irrecoverable damage to that cell. Balancers are available as add-ons or as a built-in feature of a charger, and they do a good job in preventing over-voltage damage. I recently had a problem with a 4S 3200mAh pack which was well down on capacity but which I knew had been balance-charged (or maybe chargebalanced) from new. My charger has a computer interface which shows the balancing process as a set of voltage/ time traces for each cell in the pack and I knew that although there was some imbalance at the end of the discharge, this was quickly corrected when the charge was started and all four cells in the pack were spot-on 4.2 volts at completion. I originally thought that this meant an optimum condition for the pack but the loss in capacity must mean that there was still a problem of some sort. If the problem was not in the charging process then could it be in the discharge? My charger was telling me what was happening during charge, but I had no idea what was happening to individual cells during discharge, and there was even a problem at the end of discharge as the voltages began to recover immediately discharge was stopped and the values at the start of the charge would be very different to those at the end of discharge. I did not have a facility for computer-graphing the cell voltages during discharge so had to prepare a cable which connected the balancing lead to a set of DVMs allowing me to read and note the cell voltages at fixed time intervals. I have plotted these individual cell discharge voltages in Graph 1 and compared them to a set from a new pack in Graph 2. (Graphs on page 22) In both cases the discharge was at a constant 20 amps (approximately 6C) E.F.-U.K. 21

22 22 E.F.-U.K.

23 It is now easy to see why the first pack was producing reduced capacity. Of the 4 cells, cells 1 and 2 were OK, but 3 was well down and 4 was critically low. Even though the cells were balanced during charging, this procedure was not able to correct the problem with cells 3 and 4, and the discharge cut-off was exacerbating the situation. In this test, I used a manual cut-off when cell 4 became critical and the total voltage at this point was If an auto cut-off had been used set at 2.9 volts per cell (11.6 v total), the readings at the end of discharge would have been lower still with cell 4 being subjected to even further damage by each cycle. The point about recovery masking the extent of the imbalance is given by the cell voltages at the start of the charge, which were 3.62, 3.62, 3.55, and 3.48 volts. These give a clue that there may be a problem but do not indicate its magnitude, especially when the balanced charge brings all the cells back to 4.2 volts. the balance of our series LiPo packs in terms of discharge as well as charge. It would be nice if we could apply the same active logic that we use in charging to the pack whenever it is discharging but that may not be feasible in the model during flight. What may well be helpful is an occasional bench discharge using a system which displays the traces of individual cell voltages throughout discharge but again I do not know of such a system at the moment. I imagine that the hardware/software used for the balanced charger could be adapted to this task, i.e. a balancing charger/ discharger, but until such a unit is available I will use my set of DVMs to give me occasional checks. That, of course, is only diagnosis. The real problem is how to correct such problems when they arise, and to quote aye, there s the rub! Bob Smith My conclusions from this brief investigation are that we need to check E.F.-U.K. 23

24 New-2-U A brief round-up of new items of interest If you are a manufacturer or retailer that has something new you want to share with the readers, please send details to the Editor (details page 4) New high discharge 20c Poly-PRO Lithium Polymer cells are now available. These are the latest Lithium Polymer cells available from E-Flight in a wide variety of capacities. All packs come with a separate multi-connector PCM- Guard, which allows individual cell charging, to check cell voltage and re -balance when necessary. The PCM- Guard (optional part) plugs into the multi-connector and regulates charge voltage PER CELL to a maximum of 4.2v. All packs come as pictured on website, with high quality silicone cabling sized appropriately for expected current draw, cells are sonic welding to a PCB board. All 3S and 4S packs above 1200mAh have 2mm air gaps between cells and we use Cool Shrink perforated shrink wrap for even cooler discharging. Poly-PRO lithium-polymer, high performance 20C packs not only delivers the highest voltage and retained capacity in their class but also sport the widest set of safety features on the market. Poly-PRO 3 Cell 11.1v 1500 mah Lipo Pack discharge up to 30amps. All XXHD Gold brand lipoly packs can be discharged at a rate 20 times their capacity. Example: a 1200 mah (1.2 Amp hour) pack can be discharged at 24 amps and a 3300 mah pack at 66 amps continuous. This is NOT the peak discharge rate; it is the rate that these packs can be discharged at CONTINUOUSLY. 24 E.F.-U.K. Size 22 x 42 x 145mm Weight 271gm Use: Planes, Helicopters, Boats Configuration: 3S (2mm air gap between cells) Charge 3.3Amp Discharge 66A continuous Ref. New from the Electric Flight Store STM387 ST Model Cessna Skymaster Two Motor Electric ARF 50" wingspan, 37-1/2" long, 387 sq. in. wing area, 44 oz. flying weight. You don t have to glue anything: the airplane is made of injection-moulded foam parts that come painted and decorated. You don t have to solder anything: two geared 400 size motors come installed with electric connectors all ready to plug into our pre-connected Jeti speed control (see below: PCJES030). 5 micro servos come installed with connectors: two for ailerons and one each for elevator, rudder and nose wheel steering and they are ready to plug into your receiver. The outer wing panels plug into the centre wing section and can be removed for

25 compact transport. The included flight battery is a 9 cell, 1800 mah NiMH pack. The wall charger will re-charge this in 6-8 hours. To charge your battery at the flying field you will need a field charger. The airplane flies for about 8 minutes on each charge. At full throttle the plane takes off quickly and is capable of mild aerobatics. It is not for the total novice, but is a great second airplane. Ref. New from HOBBY-LOBBY Larger Electric Planes E-Flite Ultrastick 25 is for electric sport pilots ready to transition into the next phase of aerobatics 25 key features Fully built and covered airframe is highly prefabricated All flight control surfaces are prehinged Aft float mount is included with kit for flying off water Firewall set up for two different brushless outrunner motors Fully prebuilt and covered airframe Strong landing gear mounts for smooth grass takeoffs and landings Preinstalled steerable tailwheel Prehinged flight control surfaces Large wing area Wing designed for optional quad flaps Hangar 9 Pulse XT 40 designed for glow or electric powered. The Pulse XT comes highly recommended by Modelflight. Looks great in photos but even better in real life! Glow or electric power option built into a classic design New improved bolt together assembly Mike McConville design Latest design and construction techniques Quality materials and genuine UltraCote covering Great sport flying characteristics Fly using either glow or electric power, no electric conversion is necessary Ref.model flight electric_rc_planes.htm Ref.model flight electric_rc_planes.htm E.F.-U.K. 25

26 New Catalogue now available. Whilst MEGA Motors have been around for over 14 years now, it has never been too easy for the non-internet reading members of the modelling world to obtain data about, or even a list of, the range of motors produced by Karel Matyas. This has now been put to rights by the launch of a coloured catalogue totally in English. Although he originally included a few Ferrite motors in his range, his important claim to fame was the introduction of the Cobalt and Neodymium range of reasonably priced motors covering the popular power range of 100 to 1000W. These were well summarised at the time by the much missed Dave Jones of Silent Flight fame as affordable power and possessing grunt. Perhaps the most popular unit was the 10-cell unit which enabled many to compete at the 10- cell International level for a comparatively reasonable price. Much has moved on since then and things have not only gone brushless but also inside-out! MEGA have kept up with this in all the modelling spheres of cars boats and planes with high speed units for ducted fans boats and cars across to the slow speed outrunners initially of appeal to the power model aircraft enthusiasts. Perhaps the most striking unit is the 600 size Outrunner which will usefully turn an 18 inch propeller on 10 Nickel cells! Rather than trying to summarise the catalogue here, why not obtain a copy from Alan Fry at ImporTekniK, 29 Braiswick, CO4 5AD and phone/fax for the overall cost of 2 including postage. 26 E.F.-U.K.

27 (see also article Southern Model Air Show page 14) Photo: Keith Day Above: Group display of Electric Flight Below: Two of the planes demonstrated Photo: Keith Day E.F.-U.K. 27

28 Photo: Bill Jackson Percy (see page 13) Photo: Bill Jackson Pampered Jet Mk 3 (see page 13) 28 E.F.-U.K.

29 Photo: John Thompson RBC Channel crosser (see page 37) Pete Lewis s fleet (see page 36) E.F.-U.K. 29

30 INDOOR R/C FLYING 2006/ 7 Provided by the BMFA Northern Area GARFORTH SQUASH & LEISURE CENTRE Ninelands Lane, LS25; off the A63 Leeds-Selby Road Saturdays 2-5 pm Nov 11 - Dec 9 - Jan 13 - Feb 10 - Mar 10 5 badminton court size with high ceiling. Licensed Bar, refreshments available. Smoking in the bar only. Separate slots for Slowfly; Aerobatic; Scale; and Heli. Sub 250 and equivalent brushless motors only. Any legal frequency Proof of BMFA membership essential No free flight or IC Spectators welcome on the observation balcony Pilots 5.00 juniors 2.00 Spectators (on balcony) 1.00 Please Contact: John Thompson johnty99@ntlworld.com or Northern Area website 30 E.F.-U.K.

31 TLC from your TLO Those of you who actually read these ramblings of mine may remember back in the Winter 2005 issue of EFUK I was experimenting with reducing the weight of my 2.5m Silent Dream electric glider by substituting LiPos for NiCds. I d managed to save 10oz. by fitting a pair of 3S Kokam 1500 LiPo packs, getting me to within around 9oz. of the glider version. At the time, I couldn t find an outrunner to replace the existing Cobalt motor and gearbox that offered the right combination of low weight and ability to swing relatively large propellers at 20A on a 3S LiPo. The key number I was looking for was a kv (rpm. per Volt) similar to the Irvine 05/07 and 3:1 gearbox I was running. Why is kv so important? Take two motors, one with a high kv and one with a low number. Hook them up to the same size pack and the high kv motor will try to spin fast meaning you will need to use a small propeller to keep the current within reasonable limits. The low kv motor will spin a larger propeller at the same current. It s a good way of getting a feel for how a motor is designed to be used. High kv motors are good for ducted fans and geared set-ups, low kv for direct drive. Of course, it s not as simple as that because a low kv motor may be designed to run with high cell counts and could be hopelessly inefficient on less cells, but you get the idea. The Irvine kv is 1834 rpm per Volt, divided it by three for the gearbox gets to a kv of by Alan Bedingham around 600. There are outrunners out there with kvs in this area, but they re all great big things designed for lots of cells to replace.60 to.90 glow engines and therefore as heavy as the motor/gearbox I m using. If I was willing to use a gearbox, then there are plenty of brushless motors to choose from, but I didn t want the weight and complication that a gearbox brings. I finally found an outrunner that might do the job, a Hyperion G-2220/14 (don t ask, I ve no idea what this gibberish means) that only weighed 3oz. and had a kv of 930rpm per Volt and the specs said it was happy at 20A. OK, not quite what I wanted, but pretty close. I ran the numbers through Electricalc and yes, it would swing a propeller in the 10 to 11in. range at around 20A on a 3S LiPo at an efficiency in the order of 85%. The price was good at 43 from Robotbirds so it was time to battle the moths in my wallet and flash the plastic. When it arrived, I was a bit shocked at how small it was but pleased with how well it was made. Dunno about you, but when I get something as nicely made as this I sit there going Wow, look at that!. Er indoors just curls her lip and looks scornfully at this big kid with his new toy. They just don t understand, do they? Anyway, I nailed it to my test rig and ran some tests using a 3S 1700mAh 20C pack and various propellers. I settled on a pair of 10.5x6 Aeronaut carbon blades on a 5deg. hub that increased the diameter E.F.-U.K. 31

32 slightly to 10.75in and reduced the pitch to roughly 5in. Current was 19A and the static thrust was a massive 38oz.! Looking good. The electric Silent Dream now weighed the same as the glider version success at last! To be fair, the glider version has two 148 servos and a 600AA receiver battery plus a bit of lead for balance, the electric version has a 500AR receiver battery and mini servos, but I d got to where I wanted to go, the wing loading of both is now exactly the same at 10.6oz./sq.ft. A weight reduction over the original set-up of an 8 cell RC2400 pack and Irvine 05/07 with gearbox of 19oz! And it flies very well, plenty of climb performance, enough duration with the 1700s to keep me happy and it ll scratch away from low level in the merest sparrowfa... (sorry). I ve finally got what I wanted after some 30 years of playing with gliders. Let me explain: back in the 70s when I really got hooked on toy gliders (and real ones, but that s another story) all we had for launching them was hand tow or bungee. Hand tow needs two of you, so the bungee was the preferred launch method. Yes, it worked, but it was a pain laying it out and the parachute always dropped off to one side in the thistles and it would take ages to find it and then the line would snag on something or break and, and, and we even had one bungee nicked by the local yobs when our backs were turned, heaven knows what they wanted it for? I tried fitting a little glow motor to one of my gliders to make it self launching not really a success with that 32 E.F.-U.K. horrible oily lump hanging out in the breeze and the drag from the fixed propeller. I even built a scale Nimbus with a 0.20cu.in. four stroke on a pylon that retracted into the fuselage most of the time. One club member experimented with a drop-off power pod with a parachute which got over the weight and drag problem but led to another finding the pod when it landed. I even seriously contemplated rocket boost! (Editor: A relatively expensive option as it will cost around 3.25 for a launch) So you can see why I m so pleased to have at last found a launch method that imposes virtually no penalty on the glider s performance, just a little extra drag from the hub and blades of the folding propeller. Electric Glider Competitions So why don t I enter electric glider competitions? Mainly because I don t like any of the rules that s right, any of them. I actually ran some of the earliest tow launched glider competitions way back in the 70 s and spent a fair amount of time honing the rules to make sure that the best soaring pilots would win rather than the ones who spent the most money. I also used to fly in F3J glider competitions until that degenerated into a fastest launch then crash into a minuscule spot test for which you needed an electric winch and a strong composite glider. It s true that thermal soaring ability is still important, but not half as much as spending loads of money on the latest fashionable toy and what s this business about penalties if you overrun the max? I always used to allow a one minute overrun of the max so

33 that you could do a civilised approach and landing into a spot that was at least 50 yards square. I reckoned that any competent pilot should be capable of doing that, so if you missed either of them, you got no score. And the time started from release off the line, so screaming power winch launches weren t needed. I blame it on the Continental influence, they ve always been keen on precision duration competitions. Anyway, back to electric competitions. I don t like the BEFA rules (7 cells, either NiCd or NiMH and no recharging) because they ve turned into a race to see who can lay their hands on the highest capacity cells. The original idea was good in the days when 1700mAh or 2000mAh cells were about the best you could get, but it s got silly now that cell capacities are up to 4300mAh. Thermal soaring skill is less important than spending loads of money on the latest cells and brushless motors and gearboxes and climbing up to a dot in the sky. The BEFA Speed 400 rules were originally meant to be a low cost introduction to electric glider competition. OK, the motor is only a fiver but you need a sixty quid gearbox and a high tech carbon framed glider to be competitive which rather negates the original idea. The Australian rules are completely barmy, the only way you can win is if you re drawing 100 plus Amps! Surprise, surprise, an F5B glider did very well in one. They ve tried to mitigate this by using a thrust rig, the idea being that you measure the weight of the glider and its static thrust, and do a calculation that sets the motor time you re allowed. In theory, you should be competitive with a relatively low power (and cost) set-up. There are issues with how you calibrate the rig and who provides it for each competition, but the really scary bit is the actual test. Have you seen the picture in the August 2006 QEFI? A 700W glider on the rig running up to full power you wouldn t get me within a hundred yards of that lot. I wonder if they ve done a risk assessment? The BARCS rules changed recently to allow 200W of power and that s it. The bad news is that this requires every competitor to buy reasonably accurate test equipment and repeatability is also a major issue. You carefully set up your power train to 199W and on the day of the competition it measures 201W. What do you do now? Plus, it s dead easy to cheat by having a switch on your transmitter that limits throttle throw for the test. Unfortunately this rule also means that everyone is flying the same size glider and similar power trains, not good for anyone who only wants to enter the occasional competition and uses his/her glider for sport soaring the rest of the time, they have to buy something new to compete. I hear that they re thinking about changing to a Watt/kg rule which will allow a bigger variety of planes to enter. I reckon there s the germ of an idea here, it s getting close to what I think would be a more sensible set of rules. What I propose is a Watt hour per kilogram rule. Yes, I know, it all sounds horribly technical (I am the TLO after all), but it s not really. E.F.-U.K. 33

34 Watt hours is a measure of the real energy content of a battery relating it to both voltage and capacity in Ah, a true measure of how much grunt is available and for how long. It s a simple calculation, multiply the number of cells in the pack by the individual cell voltage and capacity in Ah Take a 7 cell pack of 2000mAh NiCd cells as an example:- Each cell is worth 1.2V and 2000mAh (2Ah), multiply these together and you get 2.4Wh. Multiply this by 7 for the number of cells in the pack and you get 16.8Wh. Simple, just read the labels and count the number of cells, no measurement required. Then you weigh the aeroplane with the battery in, hardly a complex process. Divide the Watt hours by the weight of the plane in kilograms and there you go. Minimal processing time and virtually impossible to cheat. Obviously, only cells with the manufacturer s labels on would be allowed and the labels must be visible. The tricky bit is deciding how many Wh/ kg to use as a basis for the rule. One approach could be to wind the clock back to the earlier days of the BEFA rules and base it on a typical glider used then. They used 7 cell 2000mAh packs and the gliders weighed around 2kg. The number you get is 8.4 Wh/kg, call it 9Wh/kg to make things simple. We know from experience that this amount of electric fuel is enough for five rounds and that it will get a glider to a reasonable height to go thermal hunting. The difference with this rule to any of the others is that you can use any size glider you like and any type of cell. Existing competition gliders would still be legal just by changing the battery pack. The emphasis would be on the pilot finding lift rather than the money to buy the latest cells, the electric power train is the equivalent of a towline launch to a reasonable height, from then on its pilot skill that counts. To summarise my proposed rules:- 1 Maximum of 9 Wh/kg, calculated as above, any type or number of cells. 2 NiCd and NiMH rated at 1.2V, LiPo rated at 3.7V, Lithium metal phosphate (LiPh = Saphion) rated at 3.2V per cell. 3 Cells to have manufacturer s labels clearly visible. 4 No recharging between flights. 5 One minute allowed for initial powered climb, flight time to start at motor off. 6 One minute allowed for landing if the maximum time is overrun. 34 E.F.-U.K.

35 7 Landing to be in a reasonable size area, say 25m radius, flight time zeroed if you miss it. All the other rules as BEFA competitions. Bring these rules in and I might be tempted to have a go, as it stands, I can raise no enthusiasm at all for electric glider competitions. By the way, remember what I said about using short leads on your batteries? One of our members managed to connect the positive and negative leads of his NiCd battery together because he wasn t paying attention to what he was doing. It had started fizzing and popping, so he yanked it out of the plane and threw it on And please, please, let s get a sensible set of rules working before some idiot decides to introduce a set of F5J rules with precision duration and one metre spot landings like F3J! Now I ll retire to the bunker, put on my Nomex suit and wait for the bang! Handy having a flying field that used to be a dummy airfield in the war, we ve got a nice strong bunker on site. LiPo Yet Again. I got clumsy and managed to put a dead short across one of my LiPo packs, only for a couple of seconds, and nothing exploded or caught fire. I thought I d got away with it as the battery seemed to behave normally for a couple of weeks. Then it started to bulge and the balancer was complaining when I put it on charge. The bulge was hard, not the soft bulge you get when cells puff up a bit, so I stripped the pack down to have a look. There s a picture here of the cell that was most affected, it had swollen to nearly twice normal size. I ve no idea what the mechanism is that caused this, just be warned, it could happen to you! the grass. When I came over he was standing there scratching his head wondering why his battery was getting so hot and blowing its vents while people helpfully poured water on it. I pulled the leads apart, but it was too late, one deceased battery. Now you know why I use such short leads. Before you ask, no, that wasn t how I managed to short out the LiPo pack! Don t let the smoke out! Alan Bedingham E.F.-U.K. 35

36 PANDAS (Pontefract and District Aeromodellers) Electric Fly-In 2006 by John Thompson Sunday, July 23 dawned dry with a cloudy, overcast sky and light winds, all good signs for the days flying plus the grass had been cut recently, so take-offs should be no problem. The Pontefract and District Aeromodellers (PANDAS) team was on site early to set up the TX Control tent with the flight line, and the car park was soon filling up with flyers, traders, and spectators. Thirty five pilots booked in, mostly with several models each. assortment of planes there were. Pete Lewis and his team were soon whizzing around with their supercharged EDF profile Harriers. I understand that there is an upsurge of interest in this design by Dave Chinery, which was a free plan in RCM&E many years ago. At that time the performance was very marginal but now with 40,000rpm available in WeMoTec 90mm fans and lightweight batteries, they are hot. At Blackpool I saw these hovering in a 30mph wind! Paul Crawshaw from Harrogate flew a nice twin engine Albatross flying boat. Chairman Trevor Jones started the proceedings with the pilots briefing, indicating the problems which can sometimes arise in a public park. Flying was soon in progress and what an One event tickled my fancy when a visitor tried to drive his car over our footbridge, luckily without damage and I just had to take a picture erasing the number plate out of courtesy. 36 Paul Crawshaw s fleet E.F.-U.K.

37 Ouch! Alan Wales receiving the Eric Johnson Trophy E.F.-U.K. 37

38 Phil and his RBC team were there showing the model that he and Nigel Hawes had flown across the channel to achieve a first with an electric model (photo see page 29). (Editor: This is not a first it has been done before, they just didn t realise it) Apparently, they are also claiming a British distance record. It was nice to see Cohn who runs my local model shop in Cleckheaton in attendance. Club mate Alan Wales put on a fine show with his modified Hangar 9 ARTF Mustang with big AXi to win the Eric Johnson Trophy for the highest placed PANDAS member. Unfortunately, Eric died earlier this year after a long illness. In a similar vein I was flying a twice size Ladybird, which Arthur Fox designed and built over twenty years ago. This was originally powered by an OS40FS when it was published in RCM&E in Arthur also died recently and I was given permission by his sons to convert it to electric and fly it at the shows in his memory. A 600W out runner and 14 cells (for CofG) swinging a 13 x 8 propellor gave this 84", 8lb. model a sprightly performance. Scale winning Lancaster several times and deservedly gained first in scale In the afternoon the TX Control was TX Controller Bill Winstanley virtually DIY and Bill Winstanley just had to sit there and enjoy the view. With the fine Yorkshire weather and the good grub from Barbara Jones and Kath, a Twice size Ladybird in memory of Arthur Fox The most impressive model was probably Brian Shorthouse s Lancaster from the Nejhuis plan which flew realistically 38 E.F.-U.K. Barbara and Kath, caterers extraordinary good time was had by all. Another easygoing, fine days flying. This event just gets better and better, so see you all next year. John Thompson

39 The idea behind this article originated in the requirements of ElectroSlot competitions to the BEFA/BMFA rules. These rules require the competitor to fly 5 rounds on a single battery charge using 7 sub-c NiMH cells (NiCd are also allowed but the increased capacity of NiMH means these are invariably used). Each round is an attempt to produce a flight of 15 minutes including a maximum of one minute of motor run although this can be used at any time during the flight. There is then a landing spot with points available for duration and landing accuracy. Long soaring flights can be easy in good lift conditions but not so easy if the lift deserts you. The ability to find lift and to extend the flight is often a function of the height to which the model is climbed and this depends largely upon the power output of the drive train since the poweron duration is limited to one minute per round. The competitor therefore has a balancing act to attempt. He can set up his model to give 5 minutes of power-on (1 minute per round for 5 rounds) plus any safety margin he wishes to create, and accept that this set up is going to give him a particular rate of climb and a particular height gain potential for each round. If he wishes to obtain a greater rate of climb and height gain potential he can set up to draw more power, i.e. he can increase the prop size and/or use a different motor/ gearbox, and hope that he can complete his flights with the lesser power-on time that the new set up will provide. In either case he will sometimes find that as he NiMH Recovery by Bob Smith reaches the final round of the competition his batteries, which are now probably 80% discharged, are delivering much less power, and hence much less height gain potential. Look at graph 1 on page 41. This graph displays the discharge voltage curve of a 7-cell sub-c pack of NiMH using constant current discharge at a rate to provide a 5- minute run. This is not a perfect model as in flight both the voltage and current draw of the battery reduce as discharge proceeds, but it is a good approximation and does not affect the point I wish to demonstrate. I have divided the time axis into 5 one-minute periods and you will see that for the last period in particular the voltage reduction means that the power available (in watts) is greatly reduced, and the reduction in the rate of climb is obvious to the pilot. Typical figures might be 40A at 8v giving 320W at the beginning of round 1, and 32A, 6.7v and 215W, half way through round 5, which is a 33% reduction in power. The result of this is that the pilot then tends to run the power-on climb for longer in an attempt to achieve the same height he reached in previous rounds but at a much slower rate of climb. My theory is that this is exactly the wrong approach and I will try to demonstrate this. Let me firstly define what I mean by recovery. On graph 2 on page 41, you will see an enlarged section of graph 1 with the continuous discharge curve slowly reducing voltage. If, at point X, we stop the discharge the battery voltage begins to build up or recover and follows E.F.-U.K. 39

40 Set-up of the battery test equipment 40 E.F.-U.K.

41 E.F.-U.K. 41

42 42 E.F.-U.K.

43 the upward line. When the discharge is restored at point Y the voltage reduces back towards the original curve but for a while, it is higher than during continuous discharge and therefore there is more power (in watts) available for this brief period. In fact, the ElectroSlot modeller gains a slight advantage repeatedly through the competition as he uses power in bursts in each round and recovery occurs each time he switches off the power throughout the competition. During the early rounds, the effect is too small to be apparent, but recovery might be critical in the last round when the voltage is dropping very quickly. Graph 3 shows how the discharge voltage curve might look in a situation where the pilot takes a long (30 seconds) slow power-on climb at the beginning of the slot and then a second even slower climb to use the last of his available power. He does get two recoveries but doesn t gain much. We can estimate the power available by taking the average voltages during the power-on periods so that for the first period 6.6v at 40A for 30 seconds gives 2.2 W-hours. For the second period, this is 5.4v at 40A for 30 seconds giving 1.8 W-hours, a total of 4 W-hours. If, on the other hand, he deliberately chooses to fly a pattern consisting of several short power bursts with, say, a minute between each, he would benefit from several recoveries and the total height gain potential might prove to be significant enough to extend his flight to the end of the slot. This pattern is shown in graph 4 using six short 10-second bursts of power and if we repeat the power calculations, we get 0.85, 0.83, 0.81, 0.80, 0.78, and 0.74 W-hours for the six poweron periods giving a total of 4.8 W-hours, a 20% increase over the original figures. I have to admit that tales of quarts and pint pots come to mind, and if this edition of EFUK had been published on April 1st you might well have taken it all with a pinch of snuff, but I promise you that although the testing was fairly basic the figures are realistic and there is an advantage available if you can use it. It must originate with the electrochemistry of the cells and that is way beyond my ability to explain. If you really want to complicate it, you could try to include the effects of acceleration and momentum in the model, but if you can do that whilst still searching for lift, you are a better man than I Gunga Din. Tongue in cheek, well maybe a little, but it all helps to keep the grey cells active, and that must be good for us, mustn t it? Bob Smith E.F.-U.K. 43

44 Jeti Advance Plus Programming Card by John Thompson If like me, you sometimes get confused programming speed controllers from the transmitter stick and are not sure if you have done it correctly, then help is at hand. Jeti have always been acknowledged as being at the fore front of this technology and the Advance Plus series is their latest offering. They come in ratings of 4, 8, 12, 18, 30, 40, 70, and 75 Amp, which are programmed through a tiny card with six jumpers, measuring only 40 x 45 x 3 mm, costing only 3.95! Provision is made for either Opto or BEC by means of the top two sets of pins. Operation is simple; first the jumpers are set to the required positions: Nixx is for NiCd/NiMH and Li-xx is LiPo/Li-Ion. Brake is obviously on or off. Cut Off Voltage High is 0.9v/cell for Nixx or 3.0v p/cell Li-xx. 44 E.F.-U.K.

45 Cut Off Voltage Low is 0.7v/cell for Nixx or 2.7v/cell Li-xx. Timing low (soft) for 2 to 6 pole motors and maximum efficiency. Timing High (hard) best for out runners. Cutoff Type gives the option of hard abrupt stopping when the voltage drops, or slow wind down to give more warning. Throttle curve is unusual as it gives the option of either Linear, where half throttle is 60% of full revs or Logarithm 80%. beep will verify the programming is done. Just disconnect the battery first then the ESC and the job is done. With the Opto ESC the beep will come after the RX battery (4 to 6V) has been connected to the top left connector. The pins seem to be gold plated so should last well. And that is it, tests on my Diabolitin using 5 LiPo and 40A Opto with Torcman 35/20/ 21 were perfect. Perhaps a Soft Start should have been added for gearboxes and big props but perhaps they think these are not necessary with out runners. John Thompson Now plug your Controller into the top right connection, our motor into the controller and lastly the flight battery pack. Now switch the ESC on and a single E.F.-U.K. 45

46 Electric Flight Calendar If you would like details of your event to appear in these pages please send full details to the Editor EF-UK, contact details on page 4. Please bear in mind that this magazine is quarterly so ensure that the details are sent in good time. For last minute information on events please check out the events list on the BEFA website Dates, times and, even locations of events can change at the last minute. You are strongly advised to check on events with the given contacts before setting out on your journey to any event. All BEFA flying events require proof of BMFA (or equivalent) insurance and an A Certificate to fly. For fixed wing models, any of the fixed wing A certificates are acceptable. For helicopters, a helicopter A certificate is required. All flying models must have been satisfactorily flown at least twice since build or repair before flying at a BEFA event. NO TEST FLIGHTS ON THE DAY Standing Events 1st Sunday of every month - The Brighouse Vintage MAC have been using the small airfield at Tockwith, near Wetherby, Yorkshire for several years, but have recently had noise problems. The field is now all electric & any BMFA Member is invited to fly there on the 1st Sunday in each month from 10-5pm for a small fee. Do not be put off by Vintage they fly anything! There is a concrete runway available and details of the site can be obtained Contact Derek Haviour October Pudsey Swapmeet and Indoor Fly-In by the Northern Area BMFA. Pudsey Civic Centre just off the ring road between Leeds and Bradford. Doors open 9.0am, one table free per BMFA member. Entry FREE. Indoor RC from to 5.0pm for sub 160g models only, 2 per pilot, juniors free. Free parking and refreshments available all day. Contact John Thompson (reasonable hours please) or at johnty99@ntlworld.com 15 BMFA NW Area Indoor Fly-in at the Springfield Sports Centre, Rochdale. Flying from 11am to 5pm, 3 per person, BMFA card must be shown. For more information see or KeithAtRochdale@aol.com 46 E.F.-U.K.

47 27 Basingstoke Model Aero Club (BMAC) Indoor Flying Night The location is, the Brighton Hill Community College, Brighton way, Brighton Hill, Basingstoke. RG22 4HS. Flying will be from 8.00pm till 10.00pm, in the large sports hall so there is plenty of room for flying fixed wing models like the Shock Flyers, or for polishing up your aerobatic routines with that electric helicopter. There will be a small fee to help cover the cost of hiring the hall, BMAC members 5 & 7 for non-members, spectators are also welcome at 1 / person. All are welcome, so please come along and enjoy the fun. For more info see the BMAC Web site Forum - Meetings & Events at or Contact Roy Thompson November BEFA Technical Workshop at the Royal Spa Centre, Royal Leamington Spa, Warwickshire (see website). The doors will open for traders to set-up their stands at 8am, with the doors opening to the public at 9.30am. All the usual features: Technical Presentations: The talks are still being organised, keep an eye on this page for news. Traders Fair: The invitations for traders are being prepared, keep checking back here for the latest list. Any traders wishing to attend that have not received an invitation by 30 Sep 06 should contact the Secretary, Jan Bassett secretary@befa.ef-uk.net for details and to reserve tables. Bring & Buy Stall: As usual the Bring & Buy stall will be set-up in the Foyer. Items can be registered and left at the stand from 9.00am, but trading starts only once the main doors open. If selling items please complete a copy of the registration form available on website. Please do not complete a separate form for each item, although multiple forms can be used if more space is needed. It is also essential that items are labelled with a minimum of your name & the asking price. Raffle: The raffle will take place as normal, with prizes being supplied by the traders. The draw will take place immediately prior to the last technical talk. Tickets. Due to increasing costs, we have had to increase the ticket prices for the 2006 Technical Workshop, the first increase since The 2006 prices are: 7.00 in advance * 9.00 at the door Mail orders for advance tickets must include an SAE for return of the tickets. Please also include a contact telephone number in case of queries. Mail order requests should be sent with a cheque payable to B.E.F.A., to: TWS Tickets, 111 Plantagenet Chase, Yeovil, BA20 2PR E.F.-U.K. 47

48 Alternatively advance tickets may be purchased using the PayPal button on the website. Other online payments methods are available, contact Jan Bassett for details. Ticket orders received before 30 October 2006 will be posted. After that date the tickets will be available for collection at the door as they may not arrive on time otherwise. Any questions on ticketing should be made to Jan Bassett *There is an additional charge of 25p per ticket and a handling fee of 50p per order for online tickets. This additional charge is due to the fees payable to PayPal and to cover postage of tickets. This still represents a good saving especially as you you d have to pay 2 lots of postage if applying by mail. 5 The Brighouse Vintage MAC have been using the small airfield at Tockwith, near Wetherby, Yorkshire for several years, but have recently had noise problems. The field is now all electric and any BMFA Member is invited to fly there on the First Sunday in each month from 10 to 5pm for a small fee. Do not be put off by the Vintage part they fly anything! There is a concrete runway available and details of the site can be had by contacting Derek Haviour Contact Derek Haviour BMFA NW Area Indoor Fly-in atthe Springfield Sports centre, Rochdale. Flying from 11am to 5pm, 3 per person, BMFA card must be shown. For more information see or Contact KeithAtRochdale@aol.com 24 Basingstoke Model Aero Club (BMAC) Indoor Flying Night.The location is, the Brighton Hill Community College, Brighton way, Brighton Hill, Basingstoke. RG22 4HS. Flying will be from 8.00pm till 10.00pm, in the large sports hall so there is plenty of room for flying fixed wing models like the Shock Flyers, or for polishing up your aerobatic routines with that electric helicopter. There will be a small fee to help cover the cost of hiring the hall, BMAC members 5 & 7 for non-members, spectators are also welcome at 1 / person. All are welcome, so please come along and enjoy the fun. For more info see the BMAC Web site Forum - Meetings & Events at or Contact Roy Thompson E.F.-U.K.

49 December BMFA NW Area Indoor Fly-in, see November 19 for details. January BMFA NW Area Indoor Fly-in, see November for details. February BMFA NW Area Indoor Fly-in, see November for details. March BEFA 2007 Annual General Meeting at Leamington Spa, Warks. 18 BMFA NW Area Indoor Fly-in, see November for details. More details will be published in due course. If you have an electric flight event you want to have included, please send an giving the details to webmaster@befa.ef-uk.net E.F.-U.K. 49

50 FOR SALE / WANTED Member's Sales & Wants FOR SALE New Blade Runner indoor helicopter, including 27Mhz R/C, LiPo battery & charger: 35 Hornet Helicopter FP VGC, with carbon blades: 20 All are plus postage or can be picked up from Leamington Spa. Contact: Neil Stainton Neil@ITpartnership.com FVK RIVAL 2.8m span is for sale, Co Durham. It is fitted with a Kontronik 480 brushless with 5:1 gearbox, Hacker 70A ESC, six new servos, Schulze 8 channel receiver, Carbon propeller & spinner, and comes with a 3300mAh flight battery or vno or swap - what have you got? Contact: Jim Horne HORNEGb@aol.com Puffin Models Elegant, 2.6m glider / electric glider. Flown twice, but other interests took over - no equipment fitted. Offers around 100. Kontronik Smile opto, brushless, speed controller, 40A 6-24V with Kontronik 4mm silver connectors on the output and Schulze 3.5mm connectors on the input and has been used twice. He would like to exchange for the same or very similar with BEC or sell for 65 Contact: Trevor Wain trevorwain@tiscali.co.uk WeMoTec Midi-fan fitted with an Aveox 36/24/2 sensorless brushless motor - Price 70. Contact: Jim Horne HORNEGb@aol.com 50 E.F.-U.K.

51 ...and WANTED Garry (in Australia) would like information about plans for a Vickers Vimy, preferably around 36" to 40" span but any thing would be appreciated. Contact: Garry hyphen@westserv.net.au Peter Vivian would like to contact any others in his approximate area (Camberley, Surrey) who are also new to Electric Flying, with a view to mutual assistance and support. Peter returned to model aircraft fairly recently after a 55-year break, with an interest mainly in building and experimenting (definitely NOT ARTF!). He would like to meet up with others having similar interests. Contact: Peter PGLV@aol.com Neil Stainton wants a Highlight electric fuselage, any condition. Contact: Neil Stainton Neil@ITpartnership.com E.F.-U.K. 51

52 Wanted by the Editor any of the following (see page 4 for contact details): General / Technical Articles. Hints & Tips. New Product notifications. Product Reviews. Photographs of your models. Electric Flight Event Reports. Any other item of interest to electric model aircraft flyers. Please send colour Digital photos or photographic prints (6 x 4 or bigger) to the editor. If possible, please do not send inkjet prints as too much quality is lost during the printing and scanning process. If you have no way to or write the files to a CD, please contact the Editor for other options. Photographic prints supplied will be returned, unless specified otherwise (as long as you give a return address). Digital photos should be sent at the highest resolution possible, in colour, and preferably uncompressed. Where compression is unavoidable the camera should ideally be set to the lowest compression possible and at the maximum resolution. Digital photographs can be ed to the Editor at editor@befa.org.uk Readers always like to know what equipment is fitted to models so they know what combinations work well (or not so well). Therefore please include as many details of the models in the photographs as possible, but ideally at least wing span, wing area, motor(s), gearbox(es), propeller(s) or fan(s), battery pack(s) used & the flight performance. Where articles are produced on a word processor package, please send an electronic copy - it make the Editors job much easier and quicker. Ideal formats are Microsoft Word (any version), Works word processor, WordPad or Notepad. Other formats can be accommodated, but please contact the Editor first. 52 E.F.-U.K.

53 New to ELECTRIC FLIGHT? START HERE..... You may be taking up Electric Flight for the first time or you may be converting from another discipline. Whatever your situation, help and advice is available. BEFA has prepared an information sheet which details further sources of information which you may find useful when just joining the hobby. To receive a copy, please send a Stamped Addressed Envelope (S.A.E.) to Robert Mahoney, address on page 4. BEGINNER'S GUIDE A Beginner s Guide to Electric Flight is available, which explains many of the Mysteries' of Electrics and will, hopefully, set you off on the right foot. Please send 3.00 per copy required to The Editor of EF-UK at the address on page 4. Please add 1.00 extra for overseas postage and remit in Sterling. Cheques should be made payable to BEFA. TECHNICAL HELP SERVICE Technical help is now available again for the use of all members. We regret that no telephone service is available, but all questions in writing (or ) will be answered by our Technical Liaison Officer (TLO). Please refer your queries to our TLO, to the postal or address on page 4. If sent by post, please ensure that you include an S.A.E. for a reply. CONNECTIONS SERVICE Requests are frequently received from members who wish to be put in contact with other members living in the same area. The easiest method of doing this is to place a free 'wanted' advert in the classified section of this magazine. Alternatively, a request may be made IN WRITING to the Membership Secretary who is allowed to divulge such information to members ONLY. Please supply as much information about your location as possible and please remember to include an S.A.E. for your reply. B.E.F.A. MEMBERSHIP Membership of the Association is open to all. Those who are not members of BMFA (our national controlling body) will have a subscription to EF-UK membership with none of the other benefits. Overseas members are very welcome and will be classed as full members if they belong to their own national controlling body. CONTACT For full details, please send an S.A.E. to the Membership Secretary (address on page 4) requesting a membership application form. Those with Internet access may visit the B.E.F.A. website at where you will find all the membership information you should require and a application form. E.F.-U.K. 53

54 B.E.F.A. Sales BEFA Round, Coloured Rub-down Decals - Ultra-thin & light - 50p each EF-UK Back Issues - Issues 71 to 73 and 75 to 85 are available to BEFA members at 3.00 each, or 5.00 each to non-members. These prices include UK P&P, overseas rates on application. Reprints of earlier issues may be available to special order at slightly higher cost, contact the Editor for details (see page 4). EF-UK Index. A comprehensive index of EF-UK, from issue 28 to date, is available by sending a 1 coin to cover copying and postage cost. Binders:- are available to hold 8 to 12 issues of Electric Flight U.K. Produced in dark blue with gold lettering on the spine, these cost 4.50 each including U.K. postage. Please add 1 for European postage and 2 for Worldwide postage. Please send all orders to The Editor of EF-UK at the address on page 4. Sweat Shirts & Tee-Shirts: Stock of these is now almost all gone - please contact Robert Mahoney regarding remaining stock, sizes and prices. PLEASE REMIT IN STERLING ONLY, WITH ALL CHEQUES MADE PAYABLE TO B.E.F.A. Advertisers Index BEFA Sales Fanfare... Inside Back Cover For Sale / Wanted... 5 Hyperflight.co.uk New-2-U to 26 RC Groups / E-Zone... Inside Front Cover Traplet...Outside Back Cover EF-UK advertising rates are 25 per inside or outside cover page, 20 per full page, 10 per half page, all per issue. Contact the EF-UK Editor for more details (see page 4). 54 E.F.-U.K.

55 MAIL ORDER SPORTS ELECTRIC FLIGHT FANS AND GEARBOXES FANS Morley Jet Elec Fan WeMoTec Micro-Fan (280/300/330) WeMoTec Mini-Fan (400/480) WeMoTec Midi-Fan (540/ 600/930) MOTORS MPJet Brushless motors; 9 motors; outrunners, inrunners & geared; 280 to to WEP Turbo Fanfare Silver 16T & 20T Fanfare Powermax 40T Speed v BB SP Speed v Race RE 380 / Rocket Speed 480 BB Pro Pro 480 HS Pro 480 HS BB MAXCIM BRUSHLESS Max Neo 13Y 1430 rpm/v Max Neo 13D 2470 rpm/v Maxu 35D, 21 Cell Controller Maxu 35C, 25 Cell Controller Superbox 1.6 to 4.28: Monsterbox 4 to 6.8: Motor Mount CHARGERS Speed 1 Pulse / Pk Det 4-8 cells Speed Ex Digital as above with discharge Simprop 25 cell Wheels, Wire, Servos, Fuses, Caps, Powerpole, 4mm & 2mm gold conns. GEARBOXES Master Airscrew - 2.5, 3, 3.5: MP Jet Planetary & 3.8:1-400 / Pro MP Jet Planetary & 3.8:1 - Speed MP Jet Planetary & 3.8:1-540 / MP Jet Plastic BB - 4 & 5:1-280 / MP Jet Plastic BB - 3, 3.5 & 4:1-400 / Pro MP Jet Plastic BB , 3.5 & 4:1 - Speed MP Jet Plastic BB , 2.33 & 2.8:1-540 / Mini Olympus Olympus MOTORS / GEARBOXES Speed 400 FG SpeedGear 400 4:1 Inline SpeedGear : SpeedGear : SpeedGear :1 9.6v SpeedGear 700 Neo Mini-Olympus & RE Olympus & Jamara : Jamara : PROPS M.A. Folding 12x x M.A. Wood Electric 10x6/10x x7/11x x8/12x x8/13x Carbon Folders 7x (Perkins) 8x x Slimprops 8x4, 8x6, 9x APC Electric 5½ - 12 dia. 3 to 4 (full range available) dia 5 to 15 Selection of Graupner & Aeronaut folding & fixed props. FANFARE 18 HILLSIDE ROAD TANKERTON WHITSTABLE KENT CT5 3EX Sports Electric Helpline - Phone / Fax: (01227) john.swain1@virgin.net Now online at -

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