Miss Millie

  • The Miss Millie plan was published in February 2003. The plan can be purchased at RCM&E's plan service.

Though I do dabble in part-constructed kits, I’m not much of a one for ARTF models. I prefer to design and fly my own (sad isn’t it?), and I get almost as much satisfaction from the design and construction phase as I do from the flying. The advantage is that I also know just what’s inside the model, and how to fix it when the inevitable crash happens!
Now, if your reading habits go as far back as May / June 1998, you may remember my Chunkie design - a semi-scale 92” span introduction to large modelling. It caused quite a lot of interest at the time, and many builders wrote to compliment me (nice!), or to ask when a plan for a biplane version would be available. One of these correspondents was Bert Jansson from Sweden - a builder of repute, who you may have seen in previous issues of RCM&E. Bert initially e-mailed me to clarify a point of detail on the Chunkie. Afterwards, he sent me photographs of the model as it progressed, and eventually flew - a correspondence that lead to Bert and his wife Ulla visiting us last year.

THE CONSORTIUM
While they were here, I showed Bert my drawings of a semi-scale biplane that I’d been working on. What had begun (like all good model designs) as an idea roughed-out on scrap paper, was slowly turning into a 68in-span biplane whose golden era appeal owed much to the many period features that I’d incorporated into her design. When Bert volunteered to build the prototype as a winter project, he kick-started a truly international effort that resembled a scaled-down Eurofighter or Airbus consortium. I provided the design and built the tailplane, while Bert, who did most of the other construction, also co-opted the help of his flying friends: Alf, who became project organiser; Ernst, a competent flyer and flying-field owner; and Mats, our flying evaluator and fibreglass cowling maker. All we needed now was a name for our endeavour.

Since the basic design was penned in 1999, and I had hoped that she’d be available to Nexus for the new millennium, the working title was Miss Millie. Even though domestic matters delayed the project, Bert still liked the name, so Millie she was when I sent her finished plans over to Sweden, where Bert picks up the story...

UNPROVEN DESIGN
I must admit it was with mixed feelings that I received Mike’s plans for Miss Millie. Yes, I’d previously built his Chunkie and was familiar with his design-technique, but this was a quite different matter. Millie was a completely unproven design that had never been built before. Who was I, though, to refuse the chance to build the prototype? Besides, I trust the old adage that says, ‘if an aeroplane looks right, it’ll fly right’ - and with two wings and a round engine, as all real aeroplanes must have, Millie looked right!

EXPERIENCE REQUIRED
While this model’s design shouldn’t pose any difficulties to modellers who have built from plans before, it is not a beginner’s model. There’s no need, then, to describe every nut and bolt in the construction. Instead, I’ll just highlight those areas where you might benefit from my experience with the prototype.

I started by examining the plan and trying to judge how much material I needed. The liteply specified for the high-stress parts is very hard to find here in Sweden. I have discovered, however, that caravan manufacturers use a similar sort of liteply that is much cheaper and available in larger sizes than specific modelling ply. This meant that I could make Millie’s fuselage sides in one piece, without splicing. You might think it worth checking to see whether the same materials are available in the UK.

The next step is to make a kit of parts, cutting out all the formers, ribs, fuselage sides and other bits. For items like the ribs, which have to be made in quantity, it’s handy to make yourself a template - 3mm ply is fine - or use the traditional sandwich method, cutting several parts in one operation.

LOWER WING
Building starts with the lower wing halves and their dihedral braces, as you need the complete lower wing assembly to form the seat on the fuselage, and to ensure that the front retaining dowels fit well. Begin by pinning the lower main and lower front spars to the plan, and placing the ribs over the spars. You’ll see that the aft part of each rib is unsupported, and in order to avoid warped wings it’s very important to place a temporary support strip under the ribs between, and absolutely parallel to, the main spar and the rear spar. Before you glue the ribs and riblets in place, don’t forget to drill where appropriate to carry the servo wire tube. Thereafter, trailing-edge and aileron construction follows normal practice.
When it comes to building the second wing half, you may find it useful to know that rubbing the wing plan with cooking oil will make it semi-transparent, so that you can turn it over and build the other half. Or did you already know that little trick?

FUSELAGE
Make two fuselage sides with the doubler / wing seat glued on, remembering to align each seat at 0° to the datum. It’s much easier to do this, and to cut out the slots for the rear wing-bolt mounting plate, before the fuselage is constructed. Obvious though it is to say, do ensure that you make ‘handed’ fuselage halves, and also note that the right fuselage side is slightly shorter than the left one to offset the engine thrust.

Glue formers F3 through to F6 to one of the fuselage sides making sure they are absolutely square, and then let them dry. Next, glue the second side to the formers and fit the wing mounting plate into its slots. Having checked that the wing fits comfortably in its seat, drill the centre-section plate and the fuselage mounting plate for the rear wing bolts, and fit captive nuts. Make holes in F4 and its doubler for the front wing dowels.

Wait as long as possible before you plank the front-fuselage and add the stringers to the aft fuselage. This’ll make it easier to install the radio, tank, pushrods, and what have you. I also recommend that you make a cut-out in the cockpit part of F6, and make a removable instrument panel which will make life simpler if you want to fit it out with working switches, diodes, etc.

The upper space between Fl and F2 could be filled with balsa block, and carved out for tank-access if necessary. I used part of it as a compartment for the on-board glow battery and electronics, accessed from the outside via a neat hatch.

The rest of the fuselage build is quite straightforward. The tailplane in particular I found very quick and easy as it was done by Mike! The only point of note here is that I’ve used one servo on each elevator for safety.

COWLING
How you attach the cowling to Fl is entirely up to you, but will depend to a degree on what type of cowling you use. The prototype has a purpose-made fibreglass job (everyone should have a friend like Mats!) that incorporates L-shaped aluminium pieces which correspond to similarly shaped nylon blocks on Fl.

Both aluminium and nylon mounts are drilled and tapped to take a hex’ bolt so that it’s easy to remove and replace the cowling which, incidentally, was fitted out with a commercial dummy radial engine for that extra degree of realism.
An alternative approach would be to make a cowling from balsa and ply, but don’t forget to include an exhaust ring: it adds so much to the look of the front end, and the ambitious modeller could even make it functional.

UPPER WING
The upper wing follows very much the same procedure as the lower wing except that this time you don’t need to worry about dihedral or the ailerons. It’s equally important, however, to use the temporary support strips under the ribs. Don’t cover the upper wing centre-section until the wing has been placed on the cabane struts and you’ve drilled the appropriate holes in the wing joiners and secured the captive nuts in these holes.

Speaking of cabanes, here’s another very useful tip gleaned from my experience with the prototype: I’ve connected the front cabane struts to each other with a 2mm rod, threaded at each end. This rod means that the struts can’t flex, so when you turn the fuselage upside-down to attach the lower wing or work in the radio compartment, the fuselage can rest securely on the front cabane struts and the fin-tip (Careful, though - use foam under the tip!). If you choose to do the same, then fit the rod with the upper wing mounted, and lock it in place with nuts on each side of the struts.

When it comes to attaching the upper wing to the cabane struts, I strongly recommend that you make a jig using the plan side-view. Rest the jig on the mounted lower wing, and let the upper wing sit on the jig’s upper part: if you’ve built everything right, the upper wing will also be resting on the angled parts of the cabane struts. If not, you’ll have to do a little shimming. Don’t make the mounting-holes for the inter-plane struts until you’ve checked / adjusted the fit of the wings and you’re quite sure they’re in the right place.

COVERING & PAINTING
While opinions on the question of covering differ, I must admit that I wouldn’t like to see the classy Miss Millie dressed in film.

The prototype, therefore, was covered with SIG’s Koverall (a shrinking polyester fabric), three to four coats of dope, and then sprayed with a two-part car paint, which gives a completely fuel proof and high-gloss finish. A ‘tex covering, of course, would be a suitable alternative.

POWER & WEIGHT
Our Millie’s powered by a Laser 150, which seems perfectly suited to this model; given her 7.5kg all-up weight (which gives a wing loading of around 25oz / sq. ft), I certainly wouldn’t fit anything smaller than a .120. It would probably be possible to pare off some of our model’s weight, of course, but she really does cry out for some scale detailing - and because she’s not a scale model, there’s a temptation to pile it on!

As I’ve already mentioned, I have also fitted Telco International’s on-board glow system. This isn’t really necessary for the Laser, as it runs smoothly and has excellent idle characteristics. It is very convenient when starting, though, and the battery contributes towards the 250g of ballast that were needed in the nose to match the model’s C of G to that on the plans.

FLIGHT TEST
The day that Ernst and I took Millie to the field for her first flight was warm and sunny, with thermic gusts blowing through. Even so, her take-offs were very straight, and quite scale-ish (if a little long) on three-quarter throttle.
In flight, she seemed to be neither nose nor tail heavy (so the C of G is probably right), and though she did show a tendency to bank left (of which, more later) very little trimming was needed. I did feel that some extra aileron travel would improve the aerobatic handling, though I wouldn’t go so far - as some other club members suggested - as to fit ailerons on both the upper and lower wings a la four-aileron Stearmans. All in all, though, Ernst, who is very knowledgeable about model flying behaviour, declared himself happy, and as more members arrived Millie found herself being very much admired.

The next day dawned fine and still, and we were able to make four more test flights. Take-offs were, on the whole, very easy to perform, but I found that using half, three-quarters, and full power shortened the take-off distance from 60m to 10m; on full power she climbed almost by herself without any up elevator. Her slow-flying and stall characteristics, meanwhile, are very safe and predictable: throttling right back and steadily applying more and more up elevator eventually leads to a straight stall followed by a gentle turn to the right, which is very easy to correct.
As with most biplanes, you need a touch of rudder to make clean turns, while scale-ish slow rolls need both elevator and rudder to assist the ailerons. They looked very impressive, though, as do Millie’s wing-overs, where the rudder proved itself to be very effective. Looping requires that you pick up a bit of speed - which only adds to that golden era feel - while landings are very friendly affairs. I tend to make a rather long approach, carrying a trickle of power until the last metre or two, then cut the throttle completely. She’ll then sink, slowly and steadily, until the main wheels are about to touch the ground when I bring back the stick and drop her into a three-point landing. Beautiful!

CHARACTER DEFECT
The only defect in Millie’s character appeared to be her continuing tendency to veer to the left. It was easy to correct with a touch of right trim, but it really shouldn’t have been there at all! After some careful examination, we discovered a very slight twist in the upper wing, which was simply cured by extending the starboard aft strut by 3mm. Voila! She tracked straight as an arrow with the trims neutralised.

While we were curing the warp, we also increased the aileron travel, which did improve the overall handling, though absolute precision of aileron response doesn’t seem so critical in a non-scale model like this. If you disagree, I’ve discovered that you can use a little negative exponential (I didn’t know it was possible!) to sharpen the feel of the ailerons.

FLYING FRIENDS
Friendship and companionship, international or otherwise, is what our hobby is all about, and it’s for this reason that Miss Millie has been the most enjoyable and rewarding of all the projects I’ve undertaken in my many modelling years. Not only did it afford a lot of interesting building, head-scratching, and problem-solving, but it brought me good friends in Mike and his wife Bobbie, and the help and advice of Alf, Ernst and Mats. I only wish the ARTF people would explore these rewards of scratch-building!
Many soft landings, whatever you fly.

X
Login using Modelflying Login