John Muir

I use a 2S 950mAh lipo in my modified 9X. It works very well. Why so small? It fits the compartment easily and it is very light in weight. The 9X (along with many other transmitters) was designed to balance nicely in the hands with eight nimh cells at the bottom and a great big telescopic aerial sticking out the top. With the loss of the aerial the transmitter felt bottom heavy to me so I went for a lightweight battery to compensate. The transmitter now feels really nice to use, quite well balanced and very light overall. The limited capacity isn't an issue for me, I've got two batteries and swap them over when one needs charging, so the tranny is always ready to go. Does mean charging externally and I do take care not to let the voltage drop too low, but I like it. Amazingly capable combination the 9X and ER9X with a FrSky module. Worth a bit of effort.

My old Boomerang had a strip of self adhesive trim over the wing joint to make it look neat. I would take that off and have look to see if there's evidence of glue in the joint and make sure there aren't any gaps between the two panels. If there's a bit of 'ooze' there you should be fine. The wooden joiner worked very well on mine, the wing is still in the garage, and I worked it hard. I don't think it matters how much glue is on the joiner as it fitted into a box structure and was a fairly tight fit. So long as the wing panels can't slide apart the joiner will do its job fine, in exactly the same way a removable tube joiner would. The radio should be ok, but as others have said replace all of the batteries, transmitter and receiver, get a suitable charger and make sure you understand how to charge them. If you do decide on a new radio then all you'll need to change is the receiver in the plane, as the servos will still be ok. I liked my Boomerang, it flew very well. Good luck with yours.

David O, that's the same motor as I'm using but with 2200mAh cells. I had to extend the battery tray and push the pack well back to get the balance right. I have some 1500 cells to try when I get the chance. It still seems to fly well with the bigger battery but I think the smaller battery would be the ideal setup. David H, compared to the 2830, the 3536 motor will add about 50g (2oz) at the nose, so a lighter battery pack would make it easier to get the balance right.

Hi Nick, I don't think those are the same model. The three planes being flown by Josh and his pals are from a Flite Test design, whereas the one you linked to in the first post seems to have been designed by Filken himself, who states that he just started flying a couple of months ago. My apologies if it is the Flite Test one you actually built, and I'm just getting confused, but I think the FT design looks great and obviously flies very nicely. I wouldn't be so sure about the Filken model which would be more of an unknown commodity and may have areas, moments and angles all over the place. Filken just seemed happy to get his model to fly around some circuits at speed then flop on the grass. The FT models looked properly thought out and developed. And repeatable. They had three of them going. Can see why you would want one now.

Sounds like the supplied motor has changed a few times over the lifetime of the model. I used a 28mm outrunner as that was what was suggested at the time but others have used 35mm motors without any great issues. You just have to be careful to keep the motor wires away from the motor casing so they don't get damaged. You will probably have to drill some holes in the mounting plates for the motor as well. Fine flying model. I've used it for slope soaring and off the flat and it goes well. One thing it doesn't stand up well to is having someone (me!) fall on top of it. I'm on my second wing and I haven't really flown it all that much yet.

Nick, I wonder if you could point me in the direction of the videos of it flying. The only one I've seen is the one of the maiden and it certainly isn't flying 'well' in that one. I found one of a 'swappable' Me109 and that looked pretty good, but although it uses the same bits and pieces it seemed to have completely different proportions. To be honest, the Mustang looks a bit 'stumpy' to me. It seems to have an oversize wing, a very short moment arm (the rear fuselage between the wing and tail) and a relatively small tailplane. This would all point to a lack of pitch stability which would make it a bit twitchy on the elevator. The only way to compensate would be to fly it with the CG well forward, and the further forward you move it the more up elevator (or negative tailplane incidence) you will need to stop the nose dropping. It's really hard to tell from pictures so I may be completely wrong, though BEB seems to be thinking along the same lines as me and he knows what he's on about.

It'll be fine David. It will be a fairly tight fit in the nose but with 3S battery and a 10x6 prop it will provide loads of power. You might have to move the battery back a bit for balance as your motor will be about 50g heavier than the usually fitted 28mm diam type.

Nick, it's really hard to know what's going on in your video. My interpretation would be that the plane is dropping its nose and you are giving a dab of up elevator to lift it, whereupon the whole process repeats. Am I correct? If I am, then all you need to do is use the elevator trim control to apply as much up trim as you need to get the model to fly straight and level at about half throttle. Get someone to do it for you while you're flying, or land, apply some trim, and try again. It doesn't matter if the elevator looks angled up relative to the tailplane when you're done, it might simply mean that the incidence angles haven't been terribly well thought out by the designer. I suspect that once you've done that you may find your balance point is too near the nose and you can shift it back a bit in stages, retrimming the elevator as you go. I'd also get rid of, or reduce the expo. If you find the elevator over sensitive, reduce the overall throw.

Hi Geoffrey, If that Enya is a plain bearing one that'd probably be good. The SC is probably about the same weight as a 46. I'm not saying it wouldn't fly with the heavier engines, it would just have to be flown a bit faster and getting it balanced might take a bit of work. I like your forward planning by the way. Good luck and I hope the Mrs never finds your stash! John.

I had a Musketeer and liked it a lot. Easy to build and fly. It didn't have any bad habits and was remarkably aerobatic if you wanted it to be. Mine suffered a 'technical failure' some time ago but I've got another one to fly when the weather improves. However, I think your 46 would be too heavy for it. I think it was designed with old plain bearing 35's and 40s in mind. Mine flew on an old Magnum 40, then a J'En 37 followed by an SC36. I've got an OS40FP in it this time. All of these were fine but a modern ball raced 46 would be substantially heavier and you might have to make changes to the internal layout to balance it.

I'm thinking that tailwheel doesn't look right, not because of the weight, but because it's holding the tail awfully high off the ground. I'd be worried the plane wouldn't 'rotate' on take off. Not enough angle of attack to get it airborne kind of thing. Maybe just the angle of the picture?

I've always thought you weren't supposed to use PVA or aliphatic modified PVA's on large areas because they form a bond through solvent evaporation. If you use it on large areas the only way for the solvent to evaporate is through the wood, which, particularly with ply or dense or thick balsa, means it takes ages to dry in the middle, or never dries at all, as per Peter's post above. Letting it dry first then ironing it sounds like a good idea. Also epoxy bonds through chemical reaction so would be fine. I've only used contact adhesives up to now. It didn't occur to me that UHU Por is a contact adhesive, I might try that. John.

Stuart, absolutely. So on a high wing plane with the engine low down, downthrust is good. It helps prevent pitch up due to rotational force when the throttle is opened. On a low wing plane with a high thrustline such as some flying boats and gliders with power pods, upthrust might be required to help prevent pitch down with power. And the nearer the thrustline is to going through the CG the better I suppose. That's the aerodynamicist's view of it according to what I've read. On the other hand there is still a school of thought that says downthrust is good in all sorts of models as it stops or reduces the model's tendency to climb when power is applied. I just don't get that. On most of my models I trim them to fly straight and level at cruise and when I open the taps the plane accelerates, generates more lift and goes up. When I close the throttle it comes down. If I want go faster I put in some down elevator. I'd be confused if I opened the throttle and the plane didn't climb TBH.

I agree with you Frank. The use of downthrust as a sort of automatic down elevator substitute is, in my opinion, a hangover from the days of free flight, when the model would be trimmed for best glide and lots of downthrust used to stop the model climbing excessively or even looping under power. In an aerobatic rc model it seems counter productive to me as it turns into upthrust when the plane's inverted and does exactly the opposite of what you want. I can see it might be useful in some cases where the model is always the right way up, maybe vintage or some scale models, and certainly on powered gliders, but there is never any case where down elevator wouldn't do the job just as well, if not better. In fact, the electric gliders I own don't have a lot of downthrust designed in and I tame the climb by simply mixing some down elevator to the throttle.

Dundee MAC recently held its 78th AGM.

Twisted Hobbys Crack series models from Electric Wingman or Robotbirds. There's a selection of types and sizes. I've got a Crack Yak and a Laser, both are brilliant.

I forgot to mention centre of gravity. For smooth consecutive rolls it's important not to have the CG too far forward. Turn the plane inverted in flight and if you need a load of down elevator to keep it level shift the cg back a bit. Check again and keep doing it until you only need very gentle pressure on the stick to fly inverted. Be prepared to reduce your elevator throw slightly as the model will become more responsive in pitch. Once this is done you'll find it much easier to do consecutive rolls. I think lots of people fly with the cg too far forward for 'safety' and it turns a lot of planes into unresponsive dogs. Maybe not in this particular case of course, but worth checking.

I only mentioned rudder in response to the OP's first post regarding the nose dropping when the model's on it's side. Top rudder would be the ideal way to compensate for that but it won't be any help if the plane has roll coupling to the rudder, which his funfly almost certainly will. And as I said, I wouldn't use the rudder, I'd stick to elevator in an 'up,down.up down' sequence, the point being that you need to lift the nose after every knife edge part of the roll, not just when the plane is inverted. If you only use 'down' when the plane's inverted you'll need to use almost twice as much input and things really do start to look lumpy then.

Lots of good advice there. I'd second cutting the aileron movement right down so that the model rolls at the rate you want with the stick full over. You can then concentrate on getting the up/down inputs right without affecting the roll rate, especially if you're flying mode 2. On a fun-fly model the ailerons are almost certainly massively over-sensitive for smooth flying. I'd also go with a small dab of 'up' on entry, a slightly larger dab of 'down' when inverted, then another dab of 'up' for the second roll and so on for as many rolls as you want. With a model of this sort I'd stay away from the rudder although, technically, using opposite rudder as the model passes through knife edge is the way to get a nice smooth roll. If the rudder induces a roll as a secondary effect though it won't help. You really want to be using the elevator to lift the nose after each turn through knife edge when it will inevitably drop. For a while the rolls will look 'lumpy' but with practice your timing will improve and it will all start to look smooth.

I'd be looking elsewhere for the answer to this problem as I can't see the battery position having that much effect on roll performance. Firstly, the aileron setup. Do the ailerons have the same degree of movement as the i.c. model or is there less expo being used? Is the expo the right way around? For JR/Spektrum it needs to be positive, for Futaba, negative. Is the electric motor a lot more powerful than the i.c. version? Does it have a much larger prop producing lots more airflow over the inner ailerons and increasing their effectiveness? On the other hand, if you want to find out if the problem is due to the battery being on top, fly it inverted for a minute or two. With the battery now underneath, the response should be better. I doubt it will make much difference personally. John

This year it's been my Twisted Hobbys Crack Laser. I can fly it at home whenever the wind drops in the early morning or late evening. As a combination of circumstances and poor weather have kept me from the field lately, it's been a life saver. Next up though is my Wot 4 with a Thunder Tiger 46PRO. In absolute terms this is easily my number one model. I had to build a new fuselage and tail for it as oil seepage was becoming a problem, so I reset the clock on it in 2012 and it's flown 37 hrs 45 mins since then. The wing, however, dates from 1992 and has 146 hours actual flying time on it now. That's including a twelve year lay-off from the hobby when it sat in the garage. I nearly always take it with me as it's the plane I feel most comfortable flying and I use it for practice and to steady my nerves if I've not flown for a while or have something new to fly. Yes, I know, I'm a nerd, I keep a log of all my flights.

Wot 4 in its various incarnations, without a doubt. Still going strong after so many years. Certainly in the UK. In the US it would probably be variants of Das Ugly Stick. Worldwide, I imagine the Easystar/Bixler/Floater Jet type models must be top of the heap in terms of sales nowadays. I wonder how they'll stand the test of time?

One I liked was a TV movie called 'Birds of Prey'. It had David Janssen playing a traffic spotter in a Hughes 500 witnessing a robbery and chasing the bad guys who make their getaway in an Alouette II. Some of the best flying and best stunts ever. And Dr Strangelove .

If it's a DX4e then it has servo reversing, dual rates (fixed 70% on all surfaces), trims, delta mixing, buddy box facility and if you google 'DX4e expo' you'll find instructions that will let you activate exponential on it too. You don't need any more than that. When I started flying that would have been the spec of a top-of-the-range radio! You will probably need a y-lead to connect the wing servos to the receiver although I believe some Spektrum receivers have channels 2 and 6 connected internally to use with dual aileron servos. Not a Spektrum user much any more, so not sure on that point.

I type too slowly.