Avro Avian (oz15697)

About this Plan

Avro Avian. Free flight scale model biplane, for 0.5 to 0.75 cc engines.

Quote: "Aviate with an Avian! Build this small-diesel scale beauty by John
Watters - and take it to Old Warden for our Scale Weekend..

IN THE JULY 1986 issue of Aeromodeller, Geoff Clarke included a short feature entitled 'Subjects for Scale', which was a presentation of a few three-view drawings for aircraft thought suitable for flying scale models. The Avro Avian aroused my interest for two reasons. Firstly, it was similar to the DH Cirrus Moth (oz1794) that I had designed and built some time ago, which is now in a somewhat well-flown state, and in need of replacement! Secondly, as I live within easy reach of the Manchester Air and Space Museum, I could obtain some detail information from viewing the Avian they have on display. Although that particular example is an Avian IIIA, it does have many features common to the IVM - the 'M' indicating a metal-tube fuselage structure.

As a full size aircraft the Avian, which was first designed for the 1926 Lympne Trials was very popular. It was used by quite a number of flying schools and clubs in England and overseas and enjoyed substantial private ownership. The type has quite a number of historic flights to its credit, notably 'Bert' Hinkler's 1928 flight in the prototype from Croydon to Darwin in 15-1/2 days. During the course of a seven year production run, Avians were fitted with many types and make of engine, both inline and radial.

The all-wooden Avians, Mks I to IV, were grouped under the constructor's type number 594 but the steel fuselage IVM earned the new designation Avro 616 when it appeared in 1929. In common with many others of this type, Avian G-ABCD - the subject of our plan - was equipped with a 105hp ADC Cirrus Hermes, an upright installation that happily allows for trouble-free motor operation with our miniature.

The full-size 'BCD was first registered on 14th July 1930, surviving until the end of 1938. According to Eddie Riding's Avian feature in the August 1944 Aeromodeller, its colour scheme was typical of the period, being all-aluminium with maroon trim and lettering. In this guise 'BCD was owned by the South Staffs Aero Club at Walsall Airport, although it could boast three private owners before that.

The model is designed around the Allbon Dart 0.5cc motor, which I found was quite adequate for the similarly-sized Cirrus Moth. Generous motor space will allow for a variety of motors, but 0.75cc would be the practical maximum.

Fuselage: Construction of this component is quite straightforward. First build two identical side frames one on top of the other. The longerons should be from spruce or very hard balsa. Uprights and other members can be from softer grade balsa. The plywood formers F1 and F2 should be glued together with the engine bearers to form a separate unit, F2 being pre-drilled with small holes to take the binding for the undercarriage and cabane struts.

The two completed and lightly sanded fuselage sides can now be glued into position on formers F1 and F2. After this structure has set, the two ends of the frames should be pulled together at the tail and former F8 added. Check that the structure is square and true before anything has set.

Former F4 can now be glued in place, followed by the remaining top formers, F4A and F5 to F7. These should all be allowed to set thoroughly before fitting any of the bottom spacers. At this stage the cabane wines should be bound and glued to the former and cross-piece. The undercarriage wire U1 and the bottom wing holding dowels can also be positioned.

The fuselage top decking can now be added. This 1/32 sheeting is best pre-formed by soaking the sheet in water until it is thoroughly wet, then carefully bending it over the formers and holding in place either with elastic bands or wrapped-around tape. Left overnight, or even lightly baked to dry out will result in the sheeting adopting a permanent curvature which makes it much easier to fit without cracking. The grain of the bottom sheeting should be across the width of the fuselage. Pieces of block and sheet balsa are used to form the nose; and at this stage the fuselage structure can be sanded smooth and the nose section blended into shape...

Cut-outs for the two cockpits are now made, and the bottom wing rib fairings added to either side of the fuselage. The fuselage side stringers must be made from a resilient material. From past experience, general handling alone can crack balsa strips. Thin strips of spruce or bass wood are ideal for this job. At the nose the strips should butt up to the side of the vertical spacer; at the tail they lie on top.

The top wing centre section fuel tank can now be constructed (without the sheeting as yet) and the interplane strut wires are bound and epoxied to the tank spars and wing dowels. The undercarriage leg wires U2 and U3 can also now be bound and soldered in place. A small spring or elastic band is used as a shock absorber to hold the front end of U3 in place. Top and bottom sheeting can now be added and the tank is sanded to shape.

The nose/engine cowling is best made from materials you already find easiest to work with. I used printers' thin litho plate, although a built-up balsa and card cowling can look just as effective..."

Note: Stitched, aligned, rescaled. Now at 300 dpi.

Supplementary file notes

Article.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction