John Muir

Phil, I had a Mascot too, a Chart version, and it too went in from inverted flight, reducing itself to splinters. The reason was similar as well. I had a brown out of the brain due possibly to inadequate sugar supply. Lovely plane though. I had a Magnum 40 in it. Flew it on 3 channels for a while then put an aileron wing on it. For general flying about there really wasn't any difference but it was obviously capable of more aerobatics on 4 channels. If only I had been too.

Cover seperately, then hinge. Much easier. You can get covering onto the aileron ends and so on easily. You could iron the covering across the hinge line to seal it, which improves the efficiency of the aileron and can help reduce a problem known as 'flutter', but on a sport or trainer model such as the Flair Cub, it is completely unneccessary. It's also possible to hinge the ailerons using the covering itself, but, again, it isn't the easiest way to do it and usually the plane will have ailerons which are designed for this (i.e. hinged at the top, rather than in the centre). HTH, John.

The two fuels are practically identical. The Optifuel uses 18% Klotz Techniplate synthetic oil while the Formula Irvine has 18% Klotz Super Techniplate which is 80/20 synthetic/castor. Having used both I would be hard pressed to say I noticed a performance difference, but Optifuel is a little cleaner while the MT stuff smells better. John.

I was flying alongside one of our oldest and longest serving members last week. He was more or less running the club when I first visited back in the seventies so must have been a member for, at the very least, 45 years. It was his birthday last week and he had bought himself a Weston fun-fly model, complete with West 36 which wasn't quite behaving, so he had to do two or three very neat deadsticks and was very pleased when the engine finally kept running and he was able to make a perfect power on landing on his last flight. He wasn't exactly ringing it out but his flying was smooth and tidy as always and quite fantastic for an 87 year old I thought. The club itself is 78 years old and I've been a member for about 30 years. John.

I've used quite a few of those e-max servos and I'd never noticed where the lead exited, largely because I've only used them in small foam models. Brilliant. Must pay more attention in future.

I had a rudder servo chatter once. It was in a conventional battery driven setup. I changed the servo three times and it still chattered. The root cause turned out to be another servo on the plane which was faulty and causing some sort of feedback issue which always showed up on the rudder channel. When I replaced that servo the problem went away. I blamed cheap servos but you never know. If you haven't done it already it might be worth unplugging each of your servos in turn to see if anything shows up.

Yes, go for four channels. I once had a Chart Mascot which flew on three channels for a while, then was upgraded to an aileron wing. If I was just cruising about there wasn't any difference. Still steered it with the same stick and it flew just as nicely either way. However, the ailerons meant I could have a lot more fun with it longer term and learn how to do rolls and crash from inverted. Bearing in mind this will be your second plane anyway, three channels would be a retrograde step. And as far as the radio goes, see what everybody else is using and get one of those. They all work fine nowadays and are cheap as chips in real terms. John.

I'm with you on this one Geoff. I brought up the very same thing once and was told that Multiplex used to make servos with plug-in leads which sounded handy. But I, like you, can't see why the lead can't exit the case from the underside, the long edge or even from above the mounting lugs, rather than the one place it can be a nuisance. John.

We were all starting to doubt the wisdom of using a glove puppet as a pilot.

7.2V. Also have a fly lead in the battery compartment with a red JST connector on it. The batteries came with these fitted. It would easily take a bigger pack, but, as I say, I like it light. I also make sure I don't fly past the voltage warning beep so if you're a slope soarer you might find the capacity slightly limiting. Nice to have so much choice though, isn't it?

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.