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Trev's Christmas Present - MPX Cularis Print
Written by Trev   
Sunday, 06 January 2008 02:50

By Trevor Barton

So, this Christmas I magnanimously thought I'd relieve Judi of the onerous task of thinking up an exciting Christmas present and suggested to her that I might like a new model.

"Oh yes," she said, looking sideways at me, "and just how much is this model going to cost?"
"Err, well, about a hundred quid ...", I replied, "for the airframe."
"Oh, well, that's not too bad."
"Umm, yes, it's not as expensive as that Bossonova." I hesitated. "There are some other bits I'd need, though."
“Ohh?", I'd heard that tone before ...
“Well there are servos, mostly, and a motor, and a speed controller, actually I think I have one of those I could use, and a receiver, well, I could take the one out of the Twinstar, so I guess there's another hundred and twenty quid's worth or so ...”, I became aware that I was burbling, so decided discretion was the better part, as they say ...
 

Anyway, so it came to pass that she too decided that the best part of £250 was worth not having to traipse around the sock, handkerchief and jumper shops in search of a present, and I got the go ahead. Well, in return she recommended for herself a bread-making course at Betty's Cookery School in Harrogate which cost the best part of the above but'll save my teeth on the crusts in years to come. So, with the matrimonial blessing in hand, I hit the shops.

Well, I hit the Northern Air Spectacular at the show-ground in Harrogate, actually, and bought myself a Scorpion 3020/12 from the nice folk at Micron. Then I hit the Leeds Model Shop and bought myself a Cularis. Then I surfed my way on the Wibbly Wobbly Web to Steve Webb models and bought myself 4 HS56HBs for the wing and a couple of HS82MGs for the elevator and rudder. Then I hit Ashtek Electronics and bought myself some connectors to make my own servo extensions and some 3 core servo cable. Then I hit the Model Shop again and bought myself a Cularis prop adapter and a 12x6 Multiplex folding prop. Oh, and Overlander for some 2700mAh AA NiMh cells which I made up into a 4-cell flat pack for the receiver battery.

Then, I sat and waited. It was a strict rule of engagement that I couldn't play with my Cularis until after Christmas. Bummer. The damn thing sat there under my desk, calling to me day after day. “Trevor,” it called, “build me!!”. But no, I resisted, and on Christmas Eve I carried it downstairs to Judi, busy wrapping the kid's presents, and said “Wrap that then!”. Well, sorry as I am to say it, she refused. So, there it sat, under the tree, brazenly naked, beckoning, calling me, “Take me, big boy, I'm yours!”.

Anyway, Christmas came, and Christmas went. Boxing Day came, and Boxing Day went. Finally, on the third day I crept upstairs and, with trembling hand reached out and stroked the box. Slowly, sensuously, I twisted the tabs on the lid, teasing them open with my fingers. Sliding my hand under the corrugated cardboard I slowly prised the lid open and, with breath trembling and heart aflutter I peered into the interior.

Actually, that last bit's an exaggeration. What I really did was rip the box open post haste and pull everything out onto the floor. And, to be honest, I'd already done that anyway before Christmas, and I'd read the instructions several times in English, German, French, and Italian, hoping some of it would make sense to an Australian.

So, to the build. Building's stressful to me. Particularly with ARTF kits, because you only really get one chance. If you screw it up, you have to buy a new kit. Years ago I used to build models myself, as a teenager and in my early twenties, but they were all from scratch, or at least kits, and if you screwed up it was easy enough to make an replacement part and fix it. That's not the case with ARTF, particularly moulded Elepor, so various parts of the build are for me high stress.

The first part was the wings. They're quite neat. You have to mount the servos, which are glued in with cyano, and make (or buy, but I made) extension leads to that they can connect into the fuselage. Then you have to glue in the spars. They're carbon, and run full length. There's a nice former on the bottom of the packing material in the box that you use to ensure that every thing's straight and level. Then comes the first stressful part – you have to glue in a cover that covers the servos and spars and servo leads. Once you do that, you no longer have access to anything inside the wing. Ever. Did I remember to put the screws back in the servo arms? Are the extensions connected securely and making good electrical contact? Are the servo arms connected in the servo neutral position? Those, and a myriad of other questions go through your mind as you're frantically spreading cyano on the spar cover (it's big, 36” by 3” or so, a lot of cyano) hoping to get it stuck down and level before the cyano goes off. Blood pounding in your head, heart racing, stomach feeling like a vindaloo supper, you finally stick down the spar cover, thinking, “Oh, bugger it, if it ain't right, I'll fix it somehow.”

Then you do the same thing for the other wing. Then rest.

There's a bit of fiddly stuff next. The wings attach to the fuselage on a neat plastic former with some clips to hold them in place. There's also a set of slots that you glue the servo cable connectors in, socket on the wing end and plug on the fuselage side. It makes for a neat Plug 'n' Play wing connector, and all you have to do is plug the wing into the fuselage and every thing's all connected and ready to rock and roll – well, less of that because it's a nice firm attachment and doesn't rock or roll at all. Anyway, that needs gluing up, but that's only a minor stress. Any mistake here will only mean that the wings are permanently attached to the fuselage, not such a bit deal for a 2.7m wingspan glider I hope to fit into a Mini.

Next comes the fuselage. Most of that is OK. You have to glue the rudder and aileron push rods and servos in, and there are a couple of stiffening spars made from GRP. The elevator horn mechanism is inside the fuselage and that needs assembling and fitting, as does the receiver battery, switch and all the wiring. The wiring's a bit of a problem, because the channel that they've cut in the side of the fuselage isn't big enough – well, it's less than half the size it needs to be so I had to enlarge it with a scalpel and a soldering iron. Not much of a problem, but I could have done without it and they should have sorted it on the kit in the first place. There's also some iron balls to go in the rear to balance the motor. Oh, and the motor mounting, don't forget that.

Then comes the next high-stress point, gluing the fuselage sides together. Once you do that, you have no more access to the elevator mechanism, or the elevator push rod (so for goodness sake don't get any cyano on it) or the receiver battery, or the wing wiring, or for that matter any of the servos. Make sure you've got plenty of masking tape ready to hold the two sides together, small strips lined up on the edge of the bench ready for use.

Work briskly, but not hurriedly – you do have time to assemble the fuselage accurately” says the manual. Huh. Whoever wrote the manual obviously didn't pay for the model out of his own pocket.

Anyway, that's the last of the stress.

Well, I say that's the last of the stress, but it wasn't the last of my stress. Trawling through the plans I happened to notice some bits in the parts list that I couldn't recall using. Wing Spar Extensions, carbon rod, 8mm OD 5mm ID 300mm length. Ever felt the blood drain from your face? You an feel it, like a sink emptying. Frantic check of the plans – ah, if you look hard enough you can see them in Fig 8. Check of the text; Oh, so that's what part 61 referred to, I thought it meant the spar cover. Quick call to Gary just to confirm my certainty. The spar extensions were missing from my kit, and I'd assembled the wings without them. You'll remember that, that was the first high-stress event, the part where I'd never have access to the insides of the wings again. Oh how well I slept that night, like a babe in arms.

Next day I legged it back to the Leeds Model Shop from where I'd bought the model. They were very kind. Supplied me with some carbon rod off the shelf. Back home, fiddled around, slotted the underside of the wings, fitted the rods, cyanoed the slotted out bits back in, covered the join with tape, wings almost as good as new, back sore and bloody from beating myself with a birch twig chanting “You will remember to check off the parts against the parts list next time ...” several hundred times.

Well, after that, finishing my sail plane was, err, plain sailing. The rudder assembly went on nicely. The control horns glue in, and there are preformed z-bends on the push rods and swivel connectors at the horn end for adjustment. The one-piece flying elevator is assembled. It's neat, because it comes off for transport using a clip arrangement for security. Then the whole thing's assembled on the floor for transmitter programming.

Well, there's another thing. I'm told that with a “proper” transmitter, like the JR 9X programming up a 4-servo wing is a doddle. Well, I don't have one of those, yet. I've got a Spektrum DX7, a lovely radio, 2.4GHz, knows all about helicopters and aileron-only winged aeroplanes, but has no facility for gliders, and particularly 4 wing servo gliders. That meant a lot of programming mixes. There's just enough mixes so I can have flap and elevator movement together, and I can just about program crow braking, but I can't do neat stuff like couple the braking to the throttle stick, because that's used for the motor and there's no way of switching it to the crow. So, the crow ended up on the three position switch, and I have either off, half or full braking depending on the switch position. What's more, there's no way of programming flight modes into the system, so I can't have, for instance, speed and thermal wing settings, and all the other nice stuff those that know about gliders say I really should have. Not the best, I'm told, but it'll do for now. I'm just waiting for February or March, when the 2.4GHz version of the 9X is supposed to be coming out in the UK, but for now I'll make do with what I have.

In the mean time, I found some useful programming instructions on the web (pdf).


That was it really. Oh, except for the very last bit, that I did on the day before New Year's Eve. I fitted the prop. Well, I say I fitted the prop, but what I really did was break the prop adapter. It's aluminium, see, but not really thinking I tightened it like I would the prop nut on an IC engine. Not surprisingly, it broke. And me an engineer.

Still, even in that lies a story. I rang the Leeds Model Shop, to see if they had one – they didn't, and couldn't tell me when they'd have one in. So, looking on the web I found that East Lancs Models in Colne did Multiplex stuff, so I rang them, hoping they were open on New Year's Eve. Yes, they did have a Cularis spinner.

“Brilliant,” said I, after giving them my details, “when do you think you might be able to get it in the post?”.
“Well actually,” said the owner, “I should be able to drop it off tonight.”.
“Oh good,” I said, breathing a sigh of relief, “that means I should get them by the end of the week.”
“No, I mean I will drop it off at your house tonight. I'm coming over to Harrogate, and it's not far out of my way to call in at Huby. I'll be there about 5”.

And, sure enough, he was.And that's what I call customer service. That's service second to none!


The rest was easy. Installed the prop, measured the static current draw – 57A at full throttle, about 580W or so. A bit much for my Jeti 40A speed controller, but that's static and the current will be less in the air, and even then the motor's only used intermittently so it'll do for now. Stupidly ran the throttle up with the tail facing a desk covered in piles of paper. Picked the paper up from where it'd blown around the room. Checked it all went together smoothly, checked the CofG again and sat back and waited for a nice day to fly it.

But that's another story. Suffice to say it lived up to its promises, and flew like a dream. A few clicks of down-trim was all that was needed, and some adjustment to the down elevator mix when the crow was activated to stop it ballooning. I flew for over an hour total on one 5300mAh LiPo, in three different flights.

All in all an excellent model. Easy to put together, quite quick, I reckon I spent 25 hours on it in all. Excellent kit, except fort the missing spar extensions, everything fitted where it was supposed to, but that's what you get with Multiplex. Flies like a dream for me, a glider virgin, and it's liked even by the experts – Gary's always flying his. I'd certainly recommend it to anyone as a first large glider. Now I want a vario ...