Red

Greetings to all Having indulged to excess, as one should over Christmas, I decided to catch up on some overdue reading, now when I say overdue I am talking about the November issue of RCM&E. I came across an article entitled "Loose Connections" penned by the entity that is Alex Whittaker. I need to say at this juncture that I am, and will continue to be, an avid reader of this contributors musings. The article is misleading in some places and inaccurate in others. Part of the article tries to persuade the reader that the analogue meter is better for quick checks than a digital meter. How so? The range on most DIY analogue meters is too wide and therefore not accurate enough. By range I mean the scale used is too wide, it will not measure any electrical property that is not a whole number. Now we all know on modern on-board power systems that measuring electrical properties needs to be extremely accurate, even when making quick checks, and this will almost always include the need to measure values less that a whole number, an analogue meter of the type in the article will not do this. The article implies the use of an analogue meter to measure a batteries voltage under load and then presents some voltage readings that include values of less that a whole volt. How were these readings obtained? They were not taken with the analogue meter featured in the article, they would have most likely been taken with a digital meter. This area of the article is hugely misleading in my opinion. The next area of contention concerns checking continuity. As the previous sentence states, you "check" for continuity, you do NOT "measure" continuity. The article suggests using ohms for checking continuity, this is plain wrong, wrong, wrong. Ohms is a measure of resistance, which can, by default, indicate continuity or an open circuit condition. I will concede that in a closed circuit there will be a measurable resistance, however, the resistance is likely to be small and therefore beyond the scope of the analogue meter. I also agree that in an open circuit there will be an infinite resistance. The analogue meter in the article has a separate function specifically designed to check for continuity. If you are checking a closed circuit which is good, a buzzer will sound, if the circuit should be closed but is not (open circuit) then the buzzer will not sound, simple. This is one function of the analogue meter that is equal to a digital meter since you are not trying to measure a value. The article also suggests that you can measure battery charge voltage against time or a capacitor discharging against time. What? You would need an oscilloscope to do that, or a separate piece of equipment to measure the time component. I would like to reiterate the point in the article that states NEVER to test for resistance in a "LIVE" circuit, this applies to continuity testing as well. Alex, you have let me down on this occasion, it is however, my new years resolution to forgive you. RED

Hi Bob I have the same transmitter and it does sound like a "V" tail mix to me. To clear this press both of the white buttons together at the same time, this enters programming mode. Then press the Mode button until you come to the V-TL screen, if it says "ON" push the right hand switch up for about a second until it says "INH". Exit programming by pressing both white buttons again at the same time for about a second. Now try all of your controls again. Good luck RED

Hi Daz As you say, maybe you have just been lucky and those of us who have snapped motor shafts have been unlucky. In my case I hold my hands up to my own lack of piloting skills as a contributing factor. Until recently, in our history of model aviation, models tended to be heavier with ic engines, larger servos, fuel tanks and more building materials used in the construction of our model airframes. What this added up to was a model that penetrated the air with more authority when the power was reduced. This trait is lacking on modern foam models and this makes it easier to tip stall on landing if adequate air speed is not kept up. I have a Wot-4 woodie (electric powered) which is heavier than my equivalent sized foam models which I have not tip stalled on landing. I know that many pilots can easily compensate for the different characteristics but until now my own ineptitude has prevented me from doing so. I have seen pilots float these foam models, almost to the point of being stationary, on landing. I don't have the ability to do this. What this all adds up to I suppose is that pilots at my level need to keep practicing and maybe put up with snapping motor shafts on a regular basis. regards RED

Thanks Allan, I have just ordered 6 shafts and also posed the question to them about the direct replacement items. I have ordered a motor from the same site as a back-up (£12, can't go wrong at this price). If the shafts fit ok (in terms of length) then I can always use the motor for another project. Actually, looking around this site (modelaccessories.co.uk) and the products they sell (at very good prices) has made this my new favourite site, so thanks very much for this. The surprise for me is the lack of comment from people who own either a Wot 4 foam-e, acro wot foam-e or a ST models MX2 as they share the same motor and are therefore prone to the same problems. Maybe everyone just replaces the motors. This, to my mind, is a shame since they are perfect for the models and are quite powerful.

Thank you both for your replies. The shaft is 55mm long and I would consider this to be the minimum. I did read on another forum that someone has tried 4mm piano wire with complete success. What do you think? Red

Hey Allan Thanks for the info. I have looked at the motor you have suggested and it does look like it will do the job. The problem I am having is having to bin 2 otherwise good motors. This is a possibility I am struggling to commit to. I now have the new bearings so I will wait a while untill I can track down some shafts. One question for you though, the motor you suggest seems shorter than the stock motor, how did you overcome this issue? regards Red

If you have a ST models MX2 or Ripmax Acro Wot foam-e then you might have suffered the same fate as my models. On approach, with both models and not at the same time I hasten to add, I tip stalled at very low level. The result, on both occasions, was a snapped motor shaft. Whilst I concede that this limits damage to the rest of the plane it is, nevertheless, very frustrating as it stops any further play. Incidentally, these two models have identical brushless motors although the KV rating may differ. So, why am I writing this blog, simples, I have struggled to get replacement shafts. I have found numerous model shops that advertise these items but none of them actually have them in stock. I noticed that some of the shops state that they have stocks elsewhere. I imagine this is simply a tactic to get you to part with your money and then you simply wait until the item is actually in stock otherwise why would you say you don't have the item in stock? Anyway, the motor shafts must, to my mind, be a problem as no one has them in stock which means that all of the stock has been bought. The problem with the shafts is the circlip groove. This creates a weak point, intentionally I think. I think the metal is also a little too brittle. I did find a seller on eBay but the seller wants a fiver each, most model retailers are selling them for about 1.99, if you can find one with them in stock! I decided to make some new shafts and so went on a hunt for some 4mm rod. I didn't have to look too far or for too log as on my next visit to my local B & Q I found some suitable diameter metal rod. I cut a length roughly the same as the original and fitted it to one of the motors. I then tested, by hand, how smooth the motor turned and also checked to see if the shaft was running true. Well, this is the point that I discovered the second fault with these motors, namely very poor quality bearings. At first I thought that I must have damaged the bearings in the original, and I must emphasise, soft nose overs originating from the low level tip stalls.However, having cut another piece of the rod and fitting it to the other motor, I discovered that these bearings were rougher that a morning after a night out, I concluded that the bearings are poor quality items indeed. I have found a UK company that supplies bearings for a wide variety of industrial applications as well as miniature bearings. I have ordered two sets of bearings and if there is any interest in this blog I will let you know shortly whether they fit and how they perform. I have yet to solve the issue of the short supply of shafts so if anyone has ideas about making substitutes I would be very happy to hear about your solutions especially if you have any experience of upgrading motor shafts in general. In the meantime, beware of tip stalls, use the rudder for directional changes at low level and not ailerons. I have reminded myself of this countless times but still my digits move the aileron stick! Ronnie D

Thank you firstly to Kevin for your rough formula. I tried this and came out with a C of G of 116mm from the L.E. at the root. I would have flown the model at this figure as I suspected that it would be slightly forward of the actual C of G position and therefore safe. Alas, I didn't need to as Eric (thank you Eric) came to my rescue with the actual C of G from the original plan which is 127mm from the L.E.. I have to say that I am always impressed with some modellers ability to approximate measurements that are close to the desired actual measurement. If I cut a piece of wood in half by guess work alone the result is Always that one half is significantly longer than the other. I had'nt realised that the original model that I built was nearly 24 years old, does'nt time fly (pun intended). Anyway, thanks again to both of you for your replies and advice. I will upload some pictures and some specs (motor, prop, power consumption ect and how it flies) in due course in case anybody would like to convert an existing model or build a new one but with an electric set-up. Many thanks Ronnie

Hi, I built a Pink Piper from a set of plans from a magazine about 20 years ago. It is a V-tail delta. It was powered by a small ic engine. Over the many years that I have stored this model oil residue has soaked into the fuselage structure and therefore I decided to build a new fuselage but with some modifications to take an electric motor and associated equipment. The build was very straight forward as I just took measurements from the original. Now that the rebuild is complete I need to find the correct C of G as I don't have the plans anymore. Can anyone help? I have looked at C of G calculators but they only seem to work if you already know the %MAC or desired C of G. Could someone please just give me the C og G or tell me how to work with the C of G calculator. Regards Ronnie

Thank you everyone who posted a view to my question of who would be best to write a review aimed at beginners. I originally looked for a couple of weeks to see if anyone had replied to my question and as there were no replys I decided that it was of no interest to anyone. Imagine my surprise and delight when looking at the forum today and finding all of your replies. I don't wish to flog a dead horse but I agree with some of the comments and disagree with others. For instance, why should a beginner necessarily be a poor photographer or be unable to articulate their views clearly? According to a recent poll the average age of modellers is somewhat advanced (many of these will be new to model flying as well as returning modellers) and there will be some very articulate folk who also know their way around a camera. Given the comment that a particular model is for a beginner, is there a caveat that the builder needs to have reasonable tactile skills? If this is the case then is the model really for a beginner? If you are an engineer then is it not feasible that you could actually build an intermediate or advanced model? Those who commented on the possible demise of the review model, remember, we are talking about a club member providing the review who, no doubt, would be supported by an instructor. If the model is checked over carefully by the instructor before any flights then events could proceed to the reviewer commenting on how they found the model to fly. I am a teacher by profession and in my experience it is sometimes better for the pupil ( the beginner) to provide comments on their understanding of something (in laymans terms) to other pupils ( this is called peer to peer mentoring) than it is for me (the expert) to provide further explanations for something I have already covered. I buy and read at least four modelling publications each month ( some better than others, but all are well written with beautiful colour photos ). There is some cross pollination (I totally understand why ) of reviews across all of the publications but there is a tone of, dare I say it, elitism particularily with regard to reviews where only the word of a renown expert will do. If you compare some of these reviews to the articles written by Alex Whittaker (a very down to earth author ) you can see what I mean. Most reviews lack humility, Alex invented the word. Anyway, I will continue to be an avid reader of modelling publications and I hope no-one takes exception to my comments. Just to add, for David, I have been a modeller for about 40 years but have only recently returned to modelling after some 20 years out of it. I don't really know whether that makes me a beginner in the true sense or not. I am a member of the Brighton model flying club. I guess my comments are aimed at getting something different within the content of a review rather than an "ipso facto" record of a build and test flight. Many regards to you all Ronnie D Edited By Ronnie Dawson on 08/08/2013 23:48:55

I have two Phase 6 gliders, as yet unbuilt. I would like to put an electric motor in the nose of one of the gliders. Has anyone done this? If you have, what set-up did you use and how did it perform?

Our modelling magazines are populated with very good articles but I have a question for anyone who may care to answer (including editors and contributors). Models are, by and large, catagorised as being for beginners, intermediate level or experts. This can refer to flying skills and or building skills. My question then is who should review a model aimed at beginners? The same question applies to the other two groups. I think that if a modelling proficianado reviews a model aimed at beginners then the review is intrinsically flawed and inaccurate since we cannot say with any certainty whether a beginner will find something easy or difficult. I have, from time to time, read reviews from beginners and it is these testimonies (few and far inbetween I have to say) that lend real insight and argument as to whether a model is for a particular group or not. Experts should provide expertise in matters of a technical nature and not reviews of models aimed at beginners. Here is an idea: Editors could run a competition aimed at model clubs up and down the country and let the winning club choose a beginner to review a model. This could be run on a monthly basis with hopefully different winners each month. There could be a short summary of the activities carried out by the winning club and a review. Hopefully I have given a few editors some fresh ideas.........what do you think? Ronny D Intermediate builder/pilot!