Kwidsin (oz8979)

About this Plan

Kwidsin. Control line sport model for 1.5 - 2.5cc engines.

Scan from DBHL, cleanup by theshadow.

ref DBHL-6410.

Direct submission to Outerzone.

Update 15/11/2024: Added article, thanks to theshadow.

Quote: "VFM? Kwidsin! Build James Barry's cheerful control-line stunt bipe for 2.5cc motors.

Here's how to entertain yourself for a couple of evenings without being arrested or waking up with a head like a piledriver and a mouth like an ash tray. You just sit down with a few lumps of wood and plastic and build yourself a snappy little control-line biplane - at least, that's what I thought; hence Kwidsin.

This latest little horror came about as a result of my trying to get rid of some scrap wood in the longest possible time, whilst avoiding the local, and to provide myself with something to play with. The design criteria were fairly simple; it had to look good, fly well and be entertaining to build. I started out with the idea of putting to use one of my vast, collection of PAW 1.49s but as the plane grew I realised that this power would be too low. I was left with an interesting choice; PAW 2.49 or Super Tigre 46. As I was fresh out of glo-fuel it had to be the 2.49.

To the board! As with all my models I started with the wings which were designed to be as light and rigid as possible. The sweepback on the top wing was, I must confess, a bit of an afterthought but the model looked naff without it. Construction is best attempted by first assembling the LE, TE, tips and diagonals flat on the building board PVA or any other relatively slow drying glue so that you've got time for a cup of coffee) and adding the ribs afterwards.

Next came the tailplane which is a rather mundane construction, as such things often are, Once I had created these essential components they were juggled around on matchboxes until they looked approximately correct, relative to reach other; and lo and behold I had some fuselage dimensions.

The next problem was to come up with a shape that wasn't just a nasty, glorified box. This was accomplished with a few cans of Newcastle's famous brew, a Stanley knife and a big piece of sandpaper.

There are a few points that some of the more astute readers may be thinking about in connection with this engineering marvel; ie why aren't there any doublers and why isn't. there any wood in the tail end. Well, long pause for breath, the tail is the wrong place for nasty, heavy lumps of wood and I just plain forgot about doublers. Subsequent crashes have proved that the fuselage is strong enough, so not to worry.

Final assembly is best carried out by covering the wings separately, sticking the tail, fuselage and lower wing together and allowing to dry. Once this has been accomplished all concentration can be directed to gluing the top wing on 'square'. As you may have gathered from the photos I'm a bit low on concentration. The original's fuselage and centre section is covered in Solartex (does anyone else get irritated by diesel fuel ruining their Solarfilm centre sections?) and Solarfilm was used for the wings.

Does it go? As for flying - mine did on 45 ft lightweight lines with the CG as shown so if yours doesn't you've probably got it too heavy in the wrong places. Mine weighed in light at 13 oz, which is just as well considering the wing area (or lack of it). Manoeuvres? Well, if you like loops, bunts, eights, wingovers and relaxed fun you ought to build a Kwidsin. Remember - it's cheaper than the pub. "

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