Wingnut's News, reviews, stories and more from Dubbo Model Aircraft Club http://www.dubbomodelaeroclub.com Volume 3 No 3, July/August 2010 Editorial As I sit here it is probably snowing in Orange. Winter is here. Despite this we are still getting some flying in. We really don't know just how good we have it some times. The poor old modellers in the Northern Good Ol' US of A and Canada spend half the year snowed in while the Poms spend the whole year wet. If you look on U Tube, you will see that the Poms fly in some really horrible conditions. If they didn't fly in the rain, they would not fly. Sunday flying has been a bit down lately though there is still a steady turn up and Grant is there no matter what. No wonder he was elected president. On days when it is wet, you can always be building something anyway. Further down there is a commentary on field safety. This was prompted by a video I saw on RC Universe. A bloke gets hit by the prop from his large four stroke. How he was not more seriously injured I will never know. See you in the air soon. Mike Happy New Year. Our modelling year starts each year on the 1st of July. Your secretary has been buried under piles of paperwork but can report that the forms and the money have been sent to MAS (Model Aircraft Society of NSW) and by now everyone that paid on time should have their cards. Many were handed out at the field and the rest were posted about a week ago. If you don't have yours, contact Mike. Thanks to everyone for filling out the forms to update our records. The form will be a little different next year so that there will be a part of it which can be handed on to the treasurer for his records and there will also be provision for putting your pension number (if you have one) on the form. MAS requires we tell them our pension number each year so the secretary needs to make sure he has that data to forward to MAS. Twenty Seven people are now registered as members. A couple did not renew their membership despite being prodded on a number of occasions and may do so eventually. There were also a couple of members who were not contactable as our records were out of date and they too may return at some stage. Receipts are available to everyone who paid Mike directly and receipts for those who paid Ian can be provided if required. See Mike or Ian. Wingnut's Wisdom Page 1 Volume 3 Number 3
The Art in Creation Gregg Kirkwood wingspan it was easy to work out the Centre of Gravity mathematically. There are four ways to get a model in the air 1. purchase a fully constructed kit, plug it together and a few hours later you have your bird in the air, 2. buy an ARF, spend a week of so gluing and bolting things together and then you are away, 3. buy a box full of wood kit and with some skill, glue it together, cover it, fit the electronics and engine and off you go or 4. build from scratch where all you start with is some drawings of the real plane. Of the four ways, I tend to follow the forth way, that of the scratch builder. My enjoyment comes from having a pile of raw materials in your shed and from that you hope will emerge something that has aeronautical form and viability and will fly. The bird I have just finished is 2500mm Schweizer SGS 1-34 Glider and built to scale where possible. I do not have information on the aerofoil section or the fuselage bulkhead templates. A schematic view showing side, top and front profile was all the information in my possession and the basis for construction. The challenge for me to reproduce the aerofoil section and the fuselage shape will be tested when (and if) this bird flies. Mistakes were made along the way especially in selecting the right glue for the participating material and the quality of balsa varied a lot and one had to be selective in what quality was used where. Weight has also been a critical issue and she weighs in at 2740grams complete with power pod and battery. The other issue was the CG position but once the aerofoil section was selected along with chord and Greg and his Schweizer powered Glider Aeronautical design and the principles of flight have been with me from a very young age. My first aircraft were free flight rubber powered models covered in tissue and dope. Next came control line before a move to RC. The icing on the cake was to learn to fly real aeroplanes. These days I am back to RC. The next construction planned is a magnetic building board, then a Piper Cub and two more gliders. For me, flying the plane is only half the fun, There is great satisfaction and a real sense of achievement in building a,model yourself and then flying the finished product. Post Script Editor's Note. The Schweizer had its first (and very short) flight on last Sunday and sadly it did not go well. The take off was not successful and the huge power of the engine pushed it into the ground. The nose needs some repairs and they are under way even now. A second flight a week later was more successful but sadly it too ended in a less than elegant landing. Repairs are under way again. Wingnut's Wisdom Page 2 Volume 3 Number 3
Safety it's everyone's business. Your 'umble scribe likes to log on to www.rcuniverse.com There are sections there for just about every type of radio controlled model from cars and motorcycles to our planes and helicopters. Every now and then a horror story is told. Most recently someone uploaded a link to a video showing How not to tune your engine. This ended with a bloke being hit by a propeller which failed while he was tuning his engine and the prop hit him rather hard in the upper chest narrowly missing his face. It could have been really nasty as at one stage he was standing over the spinning prop! The lessons from this are several 1. When props come off or throw blades, the prop or blades go forward. FAST. 2. Check your prop for nicks, breaks, cracks etc. Don't use damaged props. Ever! 3. Make sure the blades of your props are not chaffed by your spinner. A spinner should not touch a prop blade anywhere. 4. Don't stand unnecessarily in front of a running engine. You do have to be in front to start the engine but it should be set for low revs just above idle. 5. Once you start your engine, move behind the prop to tune the engine, remove the g low deiver and to test radio gear etc. 6. Don't rev engines to full power in the pits un necessarily. The pits is not the place to run in an engine. plane for them. If we all do this, it will quickly become standard practice. 9. If you can't get help, make sure the plane is pulled fully forward against the pegs so it won't jump forward unexpectedly. These three are old enough to know better but they all did considerable damage to themselves during one American Control Line Stunt competition. And finally a general comment on safety. We are all responsible for safety at the field. Should we ever have a really nasty event that calls our insurance into play, some very difficult questions will be asked by MAAA and the insurance company. So... If you see something you think is unsafe, either tell the person straight away that you think what they are doing is unsafe or tell the most senior member of the committee as he is the Safety Officer on duty. Don't forget it and don't tell others without telling the persons involved. This just starts rumours and rumours can get out of hand very quickly to no good purpose. SAFETY IS EVERYONE'S BUSINESS. 7. Don't let observers stand in front of your running engine. A Replacement for the Skyraider Mach II? 8. If you can, get someone else to make sure your model is securely held in the starting pegs. If you are watching someone else start an engine, hold their The Skyraider Mach 2 is arguably the most popular model in the club. Many members own one and even your scribe owned one for a week or so before passing it on to someone younger. Wingnut's Wisdom Page 3 Volume 3 Number 3
So when Glenn announced recently that he had one fail in flight (wing folded up) and that he was looking for an alternative I started scratching my head. The one that comes to mind immediately is the Phoenix Scanner. It is about the same size and shape is the Skyraider but is a trike with the rear wheels mounted in the wings. I suspect it would be quite easy to convert to a tail dragger though. It costs about the same as the Skyraider too. The model that the really keen pylon fliers use is the Great Planes Viper 500. With a few small mods, these things really get mobile. Sadly, they are popular and they have Great Planes written on the box and as a result they are not exactly cheap at just over $200 though there is a short form kit version from Dave Brown that many of the pylon fliers use. Another cheap go fast plane is the Phoenix Sonic. This was designed as a 25 size trainer like the Viper but with a hot 46 it also makes a good go fast plane. They are quite cheap too about $89 from Rojs Hobbies. MIXING FUEL Pre mixed fuel is getting expensive. No wonder people with larger planes are turning to petrol engines but for those of us with smaller glow engines, things have been getting expensive. So... How about mixing your own fuel? You will need 1. Something to measure with Any 1 litre jug which is calibrated in 100ml divisions will be fine but the better ones have the marks engraved or raised and not printed. Printed calibrations will almost certainly wash off. Storage You will need some containers like the ones commercial fuel come in. Any plastic or metal container from 1 litre to 5 litres will do. Do not use any food or drink containers. It is dangerous and illegal. 1. (CH3OH). This is the essential ingredient in our fuel. This IS the fuel. 2. Oil. Castor oil was all the rage once but it tends to make planes a bit gunky. It is still a very fine lubricant though and it is relatively cheap. It is also good rust protection. Synthetic oils are the modern approach. They burn and so are cleaner but they are not as good at lubricating when things go wrong. 3.. You can run a two stroke without this but a small amount makes tuning and cold starts easier and also give a small power boost. The downsides are increased bearing rust, higher fuel use as well as higher cost. A Formula 3. Some ingredients The simplest fuel formula is called FAI fuel. It is used in certain competitions and is very simple 4. A formula. 20% Castor Oil 2. Something to store the fuel in 80%. Measuring Advantages If you are going to successfully mix fuel you need an accurate measuring jug or cylinder. 1. Price this is the cheapest glow fuel you can get. Wingnut's Wisdom Page 4 Volume 3 Number 3
2. Low rust problems Running in fuel 3. Easy to make only two ingredients. There is no point wasting expensive fuel when running in new engines. Mix up a litre of the following and when it is gone, the engine could be ready to move to the other mixtures. 4. A good benchmark for testing performance of engines Disadvantages 1. Very messy in use 2. Tuning can be difficult on some engines. 3. Not suitable for most four strokes the castor eventually gums and cokes up the engine. A better formula A very good general purpose fuel contains the following. Club fuel is mixed to this formula. 70% 5% Castor oil 10% 15% This mixture has extra castor which will help the piston and liner bed in properly and less nitro because you just don't need power in an engine that is being run on the bench. Where to get your ingredients? 70% 10% The club has supplies of methanol, synthetic oil and nitromethane. The prices are as follows 20% $2 / litre $18 / litre $18 / litre This fuel works well in used engines and is OK in Japanese engines which are very finely made. Chinese engines and all new engines run better on the next choice. An even better all round formula Castor oil comes into its own when engines get hot. It does not burn as easily as synthetic oil and when it does burn, the products of the burning are still good lubricants. Castor is the oil to use when things go wrong AND in new engines. 70% 10% Castor Oil 5% 15% This mixture is excellent in most two and four strokes and even as a running in fuel though some additional castor(+5%) is beneficial with ABC engines for the first few tanks particularly in Chinese engines. At these prices, the 10% nitro, castor/synthetic fuel costs about $26.40 for four litres. This is rather better than Uncle Pete's nearly $50 for the same thing. Talk to Mike to get some. (0429 634 767 or mike@leys.id.au). Care of Fuel loves water. It is hygroscopic and will absorb water from the atmosphere. If your fuel does pick up water it will ruin the idle performance of your engine. So you should store fuel on shelves and not on the ground which encourages condensation of moisture in cold conditions. Don't store a small amount of fuel in a large container. The air in the container may contain moisture. Store fuel in dark containers (especially Wingnut's Wisdom Page 5 Volume 3 Number 3
methanol) and not leave fuel in the sun. Another Good Trainer Some attention to the above will reduce your dead sticks and also help to keep your engines in top conditon. By Mike New Members Welcome to our new members. This year we have five new members and one returning member. I have been learning how to fly now since 1989. It has been an on and off affair and I have had some good teachers and some not so good. As a result I have had more than my share of trainers. Some were good, others less so. This is one of the good ones. Tom Churchill needs no introduction to most members. He is the younger of the Churchill brothers. Keep up the good work Tom. Clive and Kim Durham have also been around for a while as associate members but have now upgraded to full membership. Welcome to you both. Matt Dorling is well known to the club. He was originally a member way back in the early days of the club and joined again recently but spent last year as an associate. This year sees his return to the fold. Welcome back Matt. Robert Smyth has only been in Dubbo for a year or so after living for many years in Brisbane. While in Brisbane he built several quite large scale boat models including a model of the RMS Titanic which was several metres long. When Robert moved to Dubbo he gave the Titanic to his former club. These days he is learning to fly R/C models. So far he has completed a Boomerang 60 ARF, a Kadet Senior built entirely from the plan and is now working on an ARF Cessna 182. Welcome Robert. Since this was written, the Kadet has had its first flight and is flying extremely well. Larry Yates has been flying R/C helicopters for some time and has also dabbled with R/C cars and boats but has now decided to try proper aeroplanes as well. Welcome to the world of wings Larry. World Models Skyraider Mach 1 ready for action. Well, I have just bought another Skyraider. But it is now what you probably think. The Skyraider Mach 2 that is so often seen at the club is a low wing trainer. I have bought the Mach 1 high wing trainer version. It's just like the Phoenix Classic. I hear you say. No it is not. I reply. It is a lot larger but it costs about the same. Classic Mach 1 Mach 2 Wing 54 (1.49m) 65 (1.65m) 54 (1.4m) Price $125 $125 $125 (These prices are the recommended prices, they are all available cheaper than that.) The Classic is really a 35 40 size trainer but the Mach 1 is a genuine 46 size model. I had one some years ago when I was in Cowra. It had an OS LA 46 in it which flew it well. I rarely got to fly it because it was so popular with other members that it was constantly being taken to teach newcomers. Wingnut's Wisdom Page 6 Volume 3 Number 3
My new one has a Saito 62 in it. (Surprise). The 62 is the same size and slightly lighter than the 56 and it powers the Mach 1 really well with plenty in reserve. An AX 46 would also do a great job. It will happily take of on just over half power. Saito 62 installed in World Models Skyraider Mach 1 The Mach 1 is extremely easy to build. Glue the two halves of the wing together then bolt the tail feathers in place and install the radio gear and engine. It took me a total of about four hours. So how does it fly? In one word Brilliantly. It needed three clicks of aileron trim and that was all to trim it. The 62 has tons of torque for doing nice big loops, she rolls well in both directions and inverted flight is a doddle. She is also nice and stable when coming in for landings. I was having so much fun on my first flight that I ran it out of fuel. I was doing a touch and go and just as it got over the fence, the noise stopped. I just put the nose down for a perfect landing in the weeds next door. It did not even fall over. So, if you are looking for a cheap trainer/sunday flier/hack, you could do a lot worse than buy a World Models Skyraider Mach 1. http://www.dubbomodelaeroclub.com Editor Mike Leys mike@leys.id.au corrections, suggestions and contributions. for Wingnut's Wisdom Page 7 Volume 3 Number 3