Simon Wright

Very nice, I need to learn more about building with Depron.

The point I was making on calculation is that, for model aviation it is so full of funny factors and margins as to become almost useless. Calculations using wood and adhesives are easy, values and factors for the allowable stresses of wood are readily available, the information is published in various locations for most woods and densities, as are the jointing factors for adhesives. Unfortunately the spruce/balsa/ply we use is of inconsistent quality and ungraded. Calculations for our typical wings with I or C beam spars , boxed with D sheeting tend to ignore the monocoque formed instead focusing on the spars and shear webbing. this builds in another margin for error and over sizing. The comments on high technology wing sections (aerofoils) raises another topic that leaves me smiling, which is the ability of the average or even highly skilled modeller to achieve a micron perfect section with a knife and sanding block. If the section is close there are very few aerofoils that allow for the sag of covering between wing bays. CNC moulds and composite wings anyone? Regarding the theory of aerodynamics and mechanical engineering I have a Degree of knowledge in both and while neither a structural or FEA engineer have a good grasp on the  complex interactions, maths and forces involved.  Basically if you build it and it flys without breaking up is it safe, and would some numbers on a piece of paper make it any safer?       Edited By Simon Wright on 26/09/2016 20:44:41

A question raised elsewhere on this forum made me reconsider an old favourite of mine regarding design of model aircraft. Namely does anyone in this hobby really design anything other than by size and shape, the mechanical and aerodynamic stuff that is. The design of the aesthetic or a beautiful shape is an art or skill that few can aspire too and not part of my rambling. My own experience of designing a large model by calculation from root principles soon foundered when I started following Rule Of Thumb (ROT) techniques. These ROT’s combined with a plethora of estimated figures for material strength, joint and other funny factors very quickly made the precision of calculated figures irrelevant and the accuracy questionable. Precision figures for Cd, Cl, Cm on aerofoils are similarly based in perfect space and are fudged to realise actual conditions. Even calculating Vmin & Vmax, the prime inputs to any strength calculation is full of little 10% margins and deductions. My latest radio has the benefit of telemetry and I intend to test out the accuracy of a few theoretical calculations, even here the accuracy of the instrumentation imparts yet more deviations. Thankfully with small mass, limited size (moment arms) and minimal payload requirement we can easily carry massive overdesign factors between 2 and 10 maybe even more. Other than providing some reassurance by numbers, design by calculation seems to be a pretty fruitless exercise compared to the alternative. I feel that Empirical design is more the norm using ‘That looks About Right’ (TLAR) techniques with a little bit of copy and paste and a bucketful of ROTs. If successful model ‘A’ has a wing area XX, tail moment YY and tail area ZZ changing the outline shapes should have very little effect on model ‘B’. Similarly construction techniques tend to follow monkey see monkey do principles with material sizes, D boxes and structures following methods experienced or seen on similar design. There is nothing wrong with this technique but it can and does lead to failure when pushing the limits of personal knowledge, materials and technology. So, after my little ramble are you an estimating mathematician or a very capable mimic.

I know it's shocking, and lets not start on the questions about what we get with full cream, semi skimmed and skimmed. Si PS : What is organic milk?

I like the turbine Cri-Cri for $25000. 140 knots but only 70 miles range.

My wife and kids call me a grumpy sod too. Discussion fora such as this are a great way to share knowledge and express opinions. There are neither right nor wrong opinions. I do feel however that any statements or opinions expressed should be capable of at least gentle scrutiny. So back to the o/p about oversized models and the 'opinions’ expressed thereafter, what, if anything do the people claiming its down to Ego, Deep pockets, one upmanship, stupidity and incompetence want to see changed? Should there be a limit on how much a model costs, more regulation based on size, weight, volume, etc. Should separation distances be updated and enforced at clubs and shows. Should there be a ban on anything new? It is okay to moan and whinge about ‘stuff’ just don’t negatively tag and label people doing stuff you don’t, forcing yourself into a ‘them and us’ mindset. If you think someone is doing something unsafe or bad for our hobby take time to think it through and tell people your thoughts on what is needed to improve it. If your idea is good, it could gain mass and end up being adopted by those that allegedly represent us/ If you can’t be bothered to fix the problems I am afraid that we are all just Grumpy old sods moaning about the price of milk!

Not too sure what the OP wanted from this discussion, I have not read all the way though the thread but find myself more than disappointed by some of the posts that I read. With only about around 40k model aircraft enthusiasts in the UK we are already a minority group and don’t need to further fractionalise our hobby/sport. After 25 years of building and flying all types of models I too have found myself gravitating to ever larger models. My fleet ranges from heavyweight 90g F3p to 120cc 3D models. I am currently researching and saving for a 170cc 42% model. This is not down to EGO, a fat wallet or any of the other demeaning comments made. Instead it is the continuation of my journey to find the model that suits my personal needs best. Cost: What does it matter what any hobbyist spends on their hobby. We each have budgets to live by and should not decry those that spend more or less than us. Some lucky folk have huge budgets to buy what they want when they want it. Others spend years building a model to spread the cost, while others buy dozens of models over a year which could fund what they perceive as an expensive model! I will not even touch on modellers who pursue competitive RC flying in its many forms as their commitment in time and money typically reaches a whole new level. Fun per £ and satisfaction. A great and fairly easy concept, but again marred by our individual preferences and circumstances. , I find that small foamie electrics and 40 sportsters/funflys deliver the best fun or laughs per pound spent. I can have a lot of fun and really do not worry too much if I pile them in. They are a quick fix or instant high, they do not however give me any great feeling of satisfaction. For satisfaction I look to my large scale aerobatic models and the pursuit of a perfect flight. Each modeller gains satisfaction from different aspects of the hobby. Each to their own . EGO: A most insulting term used here to describe those that want or have something another does not. It is human nature to strive for more or better, I could live in a rented 2 berth touring caravan on a farmers field but choose to live in bricks and mortar on my own little piece of land. Is that EGO or personal preference? Seems like sour grapes from where I am.. Safety and large model crashes: mega models (Over 20kg) are regulated and controlled way more than our average models, both the build and flight performance is witnessed and inspected with further checks required after any change or modification. There are limits on what can be classed as a model aircraft which limit the AUW and size, after that point you could still do it RC but would have to follow full size practice. In summary, if you are happy floating around with a Bixler, or tearing up the sky with a 120 sized spitfire please continue to do so and most of all have fun. If others want something different, don’t berate or insult them but rather enjoy the diversity available in this hobby.

I have never given up on glow, I fly electric and petrol too and find each to have an optimum size. For little chuck around models there is nothing to beat electric upto 2200 3s sizes. I have tried 6s to 12s electrics but the investment in equipment, batteries and power supplies is not rewarded with duration, performance or enough flights in a day. I fly petrol models at 50cc and above where the extra weight of an ignition unit and battery is barely noticeable and glow would be a no- go at these larger sizes anyway. the convenience of a liquid fuel over electrons comes in speed to refill with the same gallon of 40:1 being suitable for all my planes. I personally find petrol below 30cc to be disappointing. Glow power reigns in the 40 to 120 sizes, it is quick to fuel, easy starting and depending on tank size can provide plenty of duration. My largest glows are a 180 FS and a Moki210. Both run brilliantly and are surprisingly frugal. I do love my little OS10 and 15s too but they are run more for novelty than performance reasons. If it pulls a plane around the sky I am willing to give most anything a try. Glow dead? I don,t think so!.

So where is the best to buy new balsa from. I know of SLEC, Balsa Cabin and Inwoods. is it all of similar quality or is there a best brand?

on special... http://www.inwoodmodels.com/index.php?id_product=6767&controller=product

I had one way back when as my first IC trainer. ( I learned to fly on the Electra-Fly sp600, 8x4 and 7 x sc1700) Fitted with an OS15FP, remember that it was unable to ROG in my hands but I solo launched it okay and it flew fine, although I had no baseline to measure against.

No point arguing unless you can sort of prove less than 28 days use. Alternative activity 1 acre in a 30 acre field (shared use still requires Planning Permission). which would be classed as COU.

Posted by stu knowles on 17/10/2015 23:01:40: just crack on and keep your head down. You will need PP if someone comes along and says so, (which is only likely to happen if someone objects to what you are doing. Don't poke a sleeping tiger Have to agree. Planning law is quite clear that using for an alternative activity for more than 28 days per year requires PP. Better to just get on and fly as and when, keep quiet in every sense of the word and only apply for retrospective permission if the planning officers come knocking at your door. It is the way that the vast majority of clubs operate.   Edited By Simon Wright on 17/10/2015 23:53:46

Zimmermann, KS, JMB or MTW are in my opinion the best. https://www.youtube.com/watch?time_continue=72&v=8klnH1vLHbc

I fly DLE, not because of any brand loyalty, just because they are cheap, reliable and spares (if ever required) can be sourced cheaply and quickly off the internet. My DLE111 is now 5 years old and other than an ignition and carb rebuild kit has been faultless. Me, I would go for the DLE61, 10% larger capacity and I think it is lighter too. Easier to sort a header for the side exhaust engines. If I had spare cash I wouldnt hesitate to give the DA60 or MVVS58 a go.

Thanks for all the replies. I should have explained that I went through the planning application woes some 5 years ago due to a whingeing neighbour who complained to the planners. it was a battle and involved maps, site visits, meetings and negotiations with environmental health and councillors, separation distances and a whole load of hassle that I could have done well without. but we got temporary permission with unlimited electric but woefull IC hours. Another application for a revision of conditions was made to get permanent permission which went through with few issues. Another application for a revision of condition increased our IC hours considerably but acheived nowhere near the hours we wanted and the IC restrictions are not goodunless you are retired.. While the club is healthy and running well, the IC restrictions on Sunday / Bank holiday and lack of evening flying really limit availaility for people working typical 9 to 5 jobs. Accordingly we want to look into the possibility of some evening flying, Bank holidays as normal Mondays or Fridays and longer Sunday hours. trying to do it differently this time, can't just ask for more hours and hoping to put a mitigated risk proposal in. Already had Andy from BMFA over to conduct a noise survey to establish just how good or bad we really are, looking forward to receiving his report although I am sure it will highlight some issues. The proposal to involve the local ATC, Cubs, Scouts and to provide a donation to local charities is already in hand. The flight log was just a thought, to get data of just how often people attend, what they fly, how often and for how long. I think it would be useful information for the club officers which may or may not provide evidence for any application. Certainly could be helpful in the event of a noise complaint in identifying which model or plane contributed to a noise complaint. Still early days yet and we may finally decide to let sleeping dogs lie and continue as is.

Planning Permission - Flight Log Book at the strip? Looking to develop our flying site and its IC hours and thinking of implementing a flight log book to obtain data that could be used to support the application. Heard them mentioned before but not been involved with any club that used them, assume it would give a rough guide to attendance, models flown and total duration of flights which may or may not be useful info. Anyone have any experience good or bad?

Not read every post in this thread so please excuse me if I mention something that has already been covered. Really like the look of the kit., its a decent size airframe at 105" span and will easily carry a DLE111. Power isnt an issue, most 85cc singles have identical real world performance to 100cc twins. Vibes are less on a twin too. Had a look on the BH site and it is designed around the Zenoah 82cc which is a bit of a lump so weight is not going to be an issue either, you may find that the batteries need to be up front with the lightweight DLE. Pulling the wings off with excess power is a reality on larger airframes, full power is for uplines and wild manouvers only, Did I read that this is your intro into RC flying? If so, take your time putting this together and build a sporter or trainer to learn on tusing a buddy lead to get the thumbs working first. While it is true that large aerobats are incredibly easy to fly they do require a healthy dose of respect and restraint that tends to come after following a more normal modelling apprenticeship. this normally takes quite a few years with a fair few crashed airframes along the way. Once you have mastered flying I see no reason why you wouldn't be able to fly this model on a buddy lead with an experienced instructor. Regarding the fit out, you have a great model and engine but need to spend almost the same again on a decent install, I would expect it to have twin servos on the ailerons , individual servos on each elevator and either one really powerful servo on rudder or another pair. Thats 8 servos, preferably digital metal gear at 15 to 20 kg cm or maybe one at 35 kg/cm for the rudder. Savox 1256 or 1270s are reasonably cheap, JR are better if you can afford them. Radio, whatever flavour you want but the tx will need servo balancing facilities or you can fit a servo matching powerbox/ match box etc, oh and twin batteries on a backer system is worth having too The engine needs a decent 2 or 3 blade prop and those noise diverters need to be replaced with either cannisters or tuned pipes if you want to fly it at any club site. (96dBA at 7m is a site loser). also worth having an electronic kill switch to kill the ignition on demand. Hope that helps. Si

Posted by Owdlad on 27/09/2015 17:18:48: Strange title this one. Because in all honesty it's not the silencer that's the problem.........its the end user that's the problem simply because they know the engine is noisy and over the limit but still persist in flying the model at all costs. This is the real problem and not the cheapo silencer.......just my opinion Good post.

Our club is looking to improve its facilities over the next few years and while we have a nice strip at the moment it is considered too tight with car parking,, seating, pits, starting tables and runway crammed into 65m x 85m envelope. the strip itself is North- south and 22m x 85 m long. We are looking to extend the site to 110m x 110m forming ab L shape strip north south runway of 110m x 50m and an east west of 70m x 30m looking North. Can people please advise what they fly off, and post pictures of features like rigging tables etc that make life easier.

Thanks Allan, have to agree with that as a perfectly reasonable argument, and something that I too would sign up too if it offered a level of security. There are loopholes though, various competition classes, un-silenced control line & free flight, Noisy electric models and turbines are excluded despite being prolific noise generators. It is after all the noise that causes nuisance and complaint rather than the powersource. Unfortunately councils are not required to comply with the COP and can therefore impose all sorts of irrational restrictions based on the planning officers mood or whim and clubs still lose their sites when it goes to court even when operating below the limit. Continuing the reasonable use of guidelines argument , and apologies if it is slightly off topic but how many clubs maintain a safe separation of 30 to 50m between models and spectators? Difficult to argue a reduced safe distance when guidelines are in the handbook from our governing body.

Bob, I was shocked too, have to admit that my expectation was more in the order of 84? may have been an operator error thing but at least gives figures for comparison. the EVO silencer has a pepperpot drilled baffle 2 or 3mm holes? and is large volume, the ASP IIRC has a reflector cone with a large bore of around 10mm?  Perhaps the glow muffler isnt as good as the petrol one? we took a ride over to a field next to one of our neighbours and it was interesting to note that the noise of our models flying was clearly audible even though the meter showed no variation in the ambient noise 40-43 db. Most annoying noise from close on 600m was screaming electrics- Funjets and pusher wing whistle was clearly audible, no way this is silent flight!   Edited By Simon Wright on 27/09/2015 08:04:23

PS... what agreed noise limits? I thought that the COP cop carried no legal weight and is therefore nothing more than a guide. Edited By Simon Wright on 26/09/2015 22:22:48

Well today we did some testing of a selection of models. first, WOT 4 ARTF, EVO10GX petrol, Bolly 12 x 6.5 standard silencer with silicone extender, 78 dba max.. I would have sworn it was louder.  Changed to a 13 x 7 APC 79db max (prop noise?) Next my Pilot RC Extra 35%, DLE111 with JMB cans, and 28x10 chinese carbon prop, loudest from front, ripping at full throttle. 93db Changed to Mejzlik 27 x 12 TH DB dropped to 90, still ripping. adjusted throttle to stop ripping, now 86dba. flew nice smooth aeros on the reduced output, barely made a noise at low throttle settings used through 95% of the flight. Was lacking punch in 3D flight. DLE55 in Sukhoi, chinese noise diverter 94 dba....   Edited By Simon Wright on 26/09/2015 22:25:04

I fly anything from small electric indoor to fairly large 100cc aerobats. Best fun per £ has to go to modern electric foamies, the cost is low enough that you can really wring them out and not be worried about an arrival. In most cases a few cocktail sticks and gorilla glue sees them flying again. Good flying models can come in all sizes but 40 to 60 size glow makes a great club sport model able to cope with typical UK conditions. I dabble occasionally in electrics at this size but return to glow every time. The best flying model that I own is a 111cc Extra. It cost way too much for a toy plane and I am always concerned about re-kitting it. The way it looks in the air and how it flys makes ne happy and that is after all the reason wht we do this hobby. Returning home after a successful day with half a dozen flights leave s me satisfied in a way thaat my smaller planes don't! I have had smaller Extras and they do not fly as well, even a 60" EF cant match the big un! just my take on it.. Si