Lanzo Duplex (oz15882)

About this Plan

Lanzo Duplex. Free flight rubber duration model. Half-size vintage Wakefield.

Quote: "1/2 Scale Lanzo Duplex. John Ralph was so impressed with the Lanzo Duplex that he decided to develop it further.

A new class of rubber powered models has emerged in the last couple of years in the form of half scale vintage Wakefields. Primarily aimed at indoor flying, but robust enough to be equally good fun outdoors, there are dozens of attractive designs to choose from so there are bound to be lots appearing.

Why not join the ever-increasing band of enthusiasts and build a 'Duplex'? It's a pretty little model which is both easy to build and fly. The original famous model arguably rates as the most potent of models from the 4oz (pre-1937) era. Created by the legendary Chester Lanzo all those years ago, it is still judged by many of today's vintage fliers as 'the best'.

I built a 'Duplex' some six years ago and have flown it regularly at some of the major contests up country (since I live at Lands End, everything is 'Up Country' for me!). It's a dependable and potent performer with a stable and characteristic flight pattern which is uncannily emulated by the little one.

The half scale one was only built last year to fly at our (Cornish Vintage Aeromodellers) regular winter indoor meetings held near Redruth. However, I might add that on the morning I finished it, in late November, an unusual calm occurred enabling me to fly the model in the field at the bottom of our garden. It flew perfectly with nothing more to change than an extra bit of right rudder to tighten up the turn. I think 'Chet' was perhaps watching my progress with building the model and had arranged the calm morning for me. (Strange things happen in Cornwall!).

Building: Although the model is of simple construction, it may appear a bit fiddly so a word of general guidance and encouragement won't come amiss. Since the plan was scaled up directly from Frank Zaic's 1937 Yearbook reproduction, the rib and wing spar count is quite high which results in quite close spacing on the half scale version. You could, if you wish, simplify things by using a few less ribs and spars. However, the 'proper' version looks right and gives a stiff but light structure.

If you do stick to the plan layout, try and choose the thinnest 1/32 quarter grain sheet you can find for the ribs. Sounds daft but 1/32 (0.8mm) sheet often varies both from sheet to sheet and across a given sheet. I managed to find a bit of discarded sheet in the bottom of my 'scraps' box which was closer to 1/40 and used that. That's the nice thing about these little chaps - there is so little wood required that you can often build the whole thing out of the 'odds and ends' box!

The wing and tail spars shown are non-standard but short enough to be cut from sheet using a steel rule and a sharp knife. Similarly a set of matched longerons can be cut from a single piece of straight grained 1/16 sheet. The curved wing and tail tips are easily formed from two laminations of 1/64 ply wrapped around clingfilm-covered cardboard templates. The U/C legs and wheels are made from thin bamboo and 1/64 ply respectively. This leaves the bit which many shy away from - making the propeller!

Carving from a saw cut blank is the traditional method which some people find both satisfying and therapeutic - a sort of religion! I find it wasteful on large models and block balsa is expensive so because I have got used to laminating, that's the technique I stuck to for this little model. Several thin sheet blade shapes are cut and laminated together by gluing and wrapping onto a cylinder whilst the glue sets. The method has been around for years and is easy and cheap. The washout twist across the blade from root to tip is achieved by shaping the blades at about 15° to the axis of the cylinder as sketched on the plan..."

Lanzo Duplex from Aviation Modeller International November 1997.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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