Geoff S

Posted by Frank Skilbeck on 06/08/2016 21:20:39: Isn't this the new "B" test routine Well he would fail that most simple of manoeuvres ... straight and level flight Geoff

Posted by Peter Christy on 21/07/2016 11:13:43: To my surprise, the model was way out of trim, constantly trying to dive sharply into the deck. And whilst frantically fumbling for the elevator trim - yes - I managed to turn the TX off!!! On most transmitters, this wouldn't have been a problem. I immediately realised what I had done, and switched it back on again! Unfortunately, this was a computer Tx, and it took some seconds to re-boot! Worse, I had programmed a "throttle cut" switch, and the Tx would only boot if the switch was in the "cut" position - which of course it wasn't because I was flying at the time! The poor old Wot4 spun into the crops, sustaining quite severe damage to the fuselage, though everything else survived OK. Pete I did exactly the same last year! I'd moved my Acrowot Foam e over to 2.4 gHz with my Taranis. I was using my Acrowot as a 'sacrificial tester' and the elevator trim needed more up. I wasn't used to the transmitter having moved over from my Multiplex 3030 and switched it off. I switched back on but, being a computer transmitter it complained about certain switches (including the throttle) not being to its satisfaction so didn't start transmitting for several seconds. I'd set the fail safe on the ground, which worked perfectly and set the elevator so that he model headed for the ground with the motor off! I hadn't intended the model to be literally a sacrifice I bought a new fuselage and motor (motor shafts were out of stock everywhere) for the Acrowot and it's flying again and I've fitted the neckstrap bracket so that the main switch is harder to reach. We live and learn. I now usually set elevator trims with a little too much up for test flights on the grounds that it's more comfortable to set the trim on a climbing model rather than on one heading for the ground. From Peter's other posts, I suspect his transmitter was also a Taranis. The switch on my 3030 is far away from the trims tucked away at the top left and moves sideways rather than vertically which was part of the reason for my faux pas. Geoff Geoff

If you want to charge 2 packs which are at a similarly discharged state then connect them in series (ie as an 8 cell pack) then it would work OK. Connecting in parallel is not considered to be the best option. Glad you've had such good results from your new charger. It's the reason I never use simple wall-wart chargers unless there is absolutely no option. However, always be sure that, if you choose to charge through the transmitter charge port that there isn't an in built peak charge detect circuit (eg Taranis). I made that mistake on my shiny new Taranis and had to replace a burnt out surface mount MOSFET - not something I want to do again Geoff

What transmitters do they use at the RC Hotel? Are you saying they're on 35Mhz? Surprising. I always used a base loaded so-called rubber duck aerial on my Mux 3030 so I never thought about pulling up the antenna on a club member's model when I test flew it (and he stood beside me and never alerted me). Luckily I got away with it and landed the plane without noticing ... until afterwards Geoff

Well Traplet aren't infallible. The CNC cut hull frames (and the drawing) I bought to build my Thames sailing barge were totally wrong and wouldn't build a hull without big kinks in the chine. To be fair to Traplet they re-imbursed all the £90 the drawing, build DVD and wood pack cost with very little hassle. I'm surprised anyone would do a test glide from a hand launch for a model of that size and weight. It would probably be flying at less than the stall speed which would give the impression of being nose heavy I would think. I just power up and fly after checking CoG is reasonable and everything else checks out. I may do a short practice ground run but that's it. Geoff

Well, for me it's an opportunity to watch my sports, which rarely get a mention normally. Although cycling has been getting much more coverage in the press recently (I watched the men's road race yesterday and was gutted when Geraint Thomas crashed) the sport I used to do at every opportunity for years is dinghy racing and that only gets any coverage at the Olympics - plus, as a nation, we're quite successful at it, which is more than I was . Geoff

Percy Pilcher also flew LiIenthal style gliders in England. Sadly, he was killed when making an ill-advised demonstration flight from the steps of Stanford Hall near Loughborough. There used to be a full scale replica displayed in a room adjacent to the vintage motor cycle museum at the hall. Not sure if either are still there (though the hall, of course is!). It's many years since I last visited when the Vintage Motor Cycle Club used to hold its annual Founder's Day event there. BEB: gliders and sailplanes also have no fueled power source to overcome drag yet they still manage to achieve very long cross country flights using nature's power sources - ridge, thermal and wave lift, all of which come ultimately from the sun, just like liquid fuels do Geoff

Lots of people were either directly or indirectly involved in the development of heavier than air flight just like most inventions/discoveries. Lots of people credit Edison with inventing the incandescent light bulb yet Joseph Swan ihere in the UK has an equal claim (in fact acknowledged by Edison when the name Ediswan was used when they were sold here). Like most things 'it's more complicated than that' but people in general prefer a simple message. The first powered flight by Orville Wright lasted 12 seconds and wasn't much further than the 220 metres claimed by Dumont - I know because we walked the length of it when we visited Kitty Hawk a few years back. Well worth the visit btw. Geoff

When I joined my current club as a mode 2 flyer and I found everyone was flying mode 1 it just meant I had to test fly my own models. So that was a good thing. If I have anything I'm a bit uncertain of I wait until Ian Redshaw turns up. If he crashes one of my models then it's certain I would have done so and a lot more spectacularly. The only problem I had was that he wasn't too keen on the built in tray on my Mux3030 but he coped and still flew with thumbs. He must have long thumbs As for cold beers - all I had trouble with when I first got my Taranis was that there was nowhere to put the candelabras that fitted so well on the Multiplex. Geoff

I've been using a tray for years after I bought a universal one from M&M developments. I still have that as a spare but stopped using it a lot after I bought a Multiplex 3030 transmitter with the added parts which make it work like a tray. I used the old M&M tray when I first bought my Taranis but bought the special tray like BEB's about a year ago. It goes together quite well but I also found it needed a strip of sticky back foam under the transmitter to make it firm. I also put some foam on the bottom to stop the Perspex getting scratched when I put it down on our hard runway. I also found that it didn't hang at the right angle and needed to drill more holes in the support bracket further back. That was an advantage as it meant I could shorten the arms thus making more room for my hands. I discarded the supplied harness in favour of a simple neck strap which works perfectly for me. A few months ago it was on the ground and the wind blew a model onto it and broke one of the side arms. I've made new ones from some 11mm surfaced marine plywood offcuts I'd saved after it was used to panel our new shower cubical (never throw anything away ). I was surprised to find my home-made side arms are lighter than the Perspex originals. It's brilliant and I wouldn't be without it. It means I can fly reasonably accurately which, because my hands don't move as they should (or once did), I wouldn't otherwise. Geoff

Personally, I would never use a wall wart trickle charger except when I had absolutely no alternative. There are loads of very inexpensive chargers around that will give you an indication of just how much energy you've stored into your batteries and will also give you an idea of the battery's health. I'm also doubtful that changing from a 4.8v battery to a 6v one in your transmitter will extend the amount of time you can use it. The higher voltage will merely cause the built-in regulator to work harder and throw away the extra energy in heat. A better way to extend use time would be to buy a second 4.8v pack and change it at the field as the other becomes depleted. Geoff

Posted by Biggles' Elder Brother - Moderator on 02/08/2016 21:52:36: Wow! That's spooky Steve! I honestly don't remember the article - that's the fault of my memory not your excellent article. But then I suppose both of us being engineers leads to similar thought patterns! And logic is logic after all! BEB Memories are funny things. I returned to work for a company I'd left 2 years before and the first job I was given was to do some modifications on a project they told me I'd designed first time around. The only reason I knew they weren't kidding me was because my name was on all the drawings and documentation. I had zero recollection of ever having seen it before. Frightening! Geoff

I've just this evening done a quick run up of the motor for my Ballerina. It's a Turnigy SK3 Aerodrive 740 rpm/volt also on 4S LiPo. On a 12x6 APCE it draws around 30 amps with power consumption of 480 watts. So you see a higher kv will draw quite a bit more current and hence greater power for a given prop. As the motor maximum current is 50 amps IIRC and I have a 60 amp esc upping the power by fitting a bigger prop will be easy to do. I think BEB was the one who recommended this combination back in January and it seems spot on. One nice thing about electric propulsion is the ease of checking the drive train in the comfort of the workshop Geoff

You could just draw a line on a piece of paper pinned to your building board and use that as a centre line. A mark one eye looking down the length of the fuselage as you build will show up any differences between one side or the other. It's surprising how markedly differences are revealed just by looking. I've had a SLEC building jig for years and wouldn't be without it - I've built lots of aeroplanes using it and also a 1.2 metre long Thames sailing barge hull. It's something to think about if you get the building bug but definitely not absolutely essential. Geoff

I just use A4 sheets that come through the post with writing on one side - I think they may be bills but I'm not sure . If you need long tubes just join several together with Sellotape. There's always magazine pages, too. I only bother with wings where access is difficult to impossible - I just feed them down a fuselage free and use a long surgical retractor like Simon. There used to be loads sold on the tool stalls at shows and they're very useful. Geoff

Posted by Tom Sharp 2 on 02/08/2016 09:43:10: I looked at the build instructions for the FW 109. Although a modern laser cut kit they are still using a central mounted single servo for the ailerons. Very rare. I bought an unstarted kit of Skyshark's only sports model, a Fantasy, on eBay a few years ago and built it over winter 2015/6. It may have been a prototype kit but many of the CNC cut parts didn't fit well (the notches in the ribs were too big for the supplied spars). I converted it to electric and was quite pleased with its looks but I was disappointed with the flying quality. I'm not sure why, but it just 'feels' unpleasant in the air - perhaps it's me. What I did find odd that, whilst it also had a central aileron servo, it specified a wing bandage to join the built up wings as though they were foam. I changed it to an internal plywood dihedral brace and dual aileron servos. Perhaps that's why the flying experience is less than ideal Geoff

The load a propeller imposes on a motor is directly proportional to the pitch but to the diameter it's proportional to the square. Some time ago I made myself a table which listed the volume of different props ie the theoretical volume of air it would move with one revolution assuming 100% efficiency. It's simply the area of its arc (0.5 dia squared) multiplied by the pitch. So for example, 12x6 prop would be 6x6 = 36 multiplied by 6 which = 216 cu ins. Upping the diameter an inch to 13 gives a value of 253 cu ins. I know it's a very crude method but it gives a feel for the effect of changing a prop and the order of change in current that might result. So if you want high speed then you use a a high pitch low diameter prop and the reverse for a slow flying scale model. By bearing in mind the props volume the current draw will be similar. Geoff

On one of my bigger models (actually it only has a Zenoah 26cc engine so not big by some standards) I fitted a single sub C NiMH 2000 mAH pack but had 2 switches in parallel. I felt switches were far more likely to fail than a battery pack. I think If I opted to use to battery packs I'd OR them with a pair of Shottky diodes just for my own feeling of confidence although I guess the most common failure mode would be open circuit die to a wiring fault in which case the diodes wouldn't help but they wouldn't harm either. Geoff

There used to be stock car racing at Long Eaton speedway stadium back in the 1950s. Actually it was more like a destruction derby when the main aim was to knock other competitors off the track - great fun to watch and, apparently, relatively safe for the drivers but certainly it didn't look very safe. Each race was started by a warm up lap following a very posh Austin Atlantic. Once the flag was waved the main object for the leading drivers was to catch the Atlantic. It always made a hasty exit into the middle of the track and never got caught. Geoff

Posted by Peter Miller on 27/07/2016 11:58:35: THe people who go in for shooting game birds are not going to like the drones spoiling their sport. "Oh well Carruthers, how many brace of drones do you get today?" The model club at Long Eaton in Derbyshire had a site next door to a clay pigeon club. I suspect there were a few pot shots at models straying over the boundary. I know I was hit by falling pellets one day as we cycled past on the lane. There was a discussion on the R4 Today programme between a couple of robotics experts and they both thought the idea of drone delivered packets rather far fetched or, at least premature. One of them admitted to owning and enjoying MR technology so had some relevant experience. Geoff

I should look at the ones sold by Airtek. They're reasonably priced and the ones I've bought seem to centre very well and they have metal gears. I've never bothered with digital servos so I can't comment except I've never found a problem with ordinary servos that they might solve. I certainly can't see they'd be any real improvement for a Phoenix 2k. Mine flies well with the HK supplied ones. btw no connection with Airtek (advertised on this page) except as a satisfied customer. Geoff

Posted by Tom Sharp 2 on 27/07/2016 22:13:29: I remember that in the late 1940's and well into the 1950's, you couldn't buy a new car if you wanted one. They were building them like mad but exporting them all. How things change. Yes, the guy who worked for my dad as a TV repair man and also lived in, bought a Standard 8 that was over list price because they were so difficult to get. That would have been in 1952/3 IIRC. Geoff

Mine was my GP Super Stearman which went dead stick just after take off on the maiden. I thought I had sufficient height to land back on the patch but the tip stall crushed both wings. I bought enough wood to make some new wings but when one came up on eBay with decent wings I bought it and used the wings on mine. Still needed quite a lot of work and it took me a couple of years to get the motivation. So I now have a spare fuselage. In the end the real culprit proved to be the Mackay electronic ignition for the 30cc petrol engine which was intermittent. I didn't find out until I tried to get the engine running after the rebuild but a replacement HK sourced ignition unit cured the unreliability. It's still a bit of a hanger queen because of its size and the field assembly time but it's a pretty model. So you see, even a dedicated electric flyer can sort out liquid fuelled models ... eventually Geoff

You probably couldn't buy a new car the year I was borne nor the petrol to fuel it (1940). We had a Ford van for the business and a petrol ration (red petrol) because radios were part of the so-called home front. Dad was proud that he managed about 40mpg on our door to door accumulator round (lead/acid cells for battery radios) by driving to the top of a street and freewheeling/pushing down I flirted with cars briefly in 1964 when I bought a 1959 Farina A40 Countryman. I ran it for 9 months before part exchanging it for a new BSA Lightning motorcycle and back to my first love. Geoff

My Cirrus is likely to be built as a Moth Major which had the Gypsy Major engine inverted like the Tiggie and sharing a similar cowl. The main reason will be to enable the battery to be fitted as far forward as possible under the motor. I'll buy a Tiger Moth cowl when I order the Cirrus (did I write 'when' rather than 'if'? ) Anyway I've fitted a couple of washers under the motor mount and luckily the resultant off-centre isn't enough to foul the cowl. It doesn't look quite as neat but I guess only I will notice. Looking forward to testing but the weather looks doubtful for a few days. Geoff