Azbug (oz1810)

About this Plan

Azbug (sp. Abzug). Small power free flight model. This is a modern plan showing a half-sized version of the 1937 Abzug design. For .25cc motors.

Quote: "Dave Banks offers this attractive 22-1/2 in span little model which is perfect for the engine we have tested this month. Azbug.

This is is the tale of a model that for me turned full circle! My aeromodelling career started in the early post war years. Prior to moving to East Dulwich in 1948 when I was six, my passion for miniaturisation had been confined to making tiny replicas of cricket bats and longbows out of sticks of firewood.

The move changed all that. A short walk to the end of the road soon convinced me that we had made the right choice. I turned the corner and stood transfixed, in front of me, behind the windows of a small terraced shop, perfect in their gossamer finesse were two rubber models hanging, as though in flight. Alongside the window was crammed with various kits and accessories of every kind. (Remember these were the very first models I had ever seen).

Fortune had truly smiled on me in the shape of Pop Blackburn's Model Shop (known solely by me as the 'Secret Shop'). Ahead of me there were to be years of frustration, puzzling over banana shaped fuselages and wrinkled tissue! Not only was 'Pop' a first class modeller but also, luckily for me, he had the patience of Job and a heart of gold to match. This was just as well for my endless enquiries on matters aeromodelling would have driven a lesser mortal mad.

I can still close my eyes and mentally enter that shop, taking in the heady smell of bare floorboards, dope, diesel fuel and balsa - ahhhh! To one side of the shop was a plan chest, full of aircraft designs that customers would endlessly sift through. I still remember two; Dick Korda's 1939 Wakefield and the Abzug (oz8934) - well at least I've built one of them and I'm sure Pop would have approved if he was still alive.

Fuselage: This is the only part of the model that might cause construction difficulties. It is actually built inverted and I suggest you make it thus: begin by building the 1/8 sq structure on the plan view (from B to tail LE). Steam-form the lower longeron to conform to the side elevation and mark it with a reference point.

Make a couple of temporary card templates to support this member at the correct height and angle above the first structure. The spacers are now fitted using a strip of card to determine their length and end angles. Make sure that the opposite spacers are the same length, thus ensuring a true structure. This is not as difficult as it sounds.

Cut out the 3/16 ply motor mount and the 1/16 ply bulkhead A-A. At this point you will have to decide how you are going to mount your motor. I soldered 10 BA nuts to tin plate strips and epoxied these to the mount underside. Glue the mount at right angles to the former A-A and leave to set. While you are waiting you can glue on the 1/16 sheet infill to the underside of the tailplane and make the under fin. Note that the trim tab is hinged with .020 KS brass wire epoxied in.

Having removed the triangular section fuselage from the building board, mark the position of A-A and glue it in place, checking the alignment of this against the drawing side view. Check also that it is square head-on to fuselage. Add the 1/8 sq diagonals between A-A and B-B, now bind on the U/C with nylon thread, making sure that you bind the legs together at their lower apex as this is a stressed area. Add the 1/32 sheet turtle deck and sides (in two pieces) together with the 1/16 sheet side strakes below the bearers between A-A and B-B and add the hollowed block below the bearers. Note that the wing/tail dowels and underfin (covered) are added after the fuselage has been covered and glazed.

Wing: This is straight forward; the two outer panels are built flat on the building board, packing is required under the main spar. You can either make a tracing of the port panel or reverse the TE/LE positions. Join the centre panel, packing tips to obtain 10 degrees dihedral (see wing drg). Sheet tips are shown on the plan, my original had laminated so the choice is up to you. Also note that the leading tip member needs to be notched diagonally to suit LE.

Tailplane: This is constructed flat on the building board from 1/8 sheet with 1/8 x 1/16 infill members. In spite of the engine's low weight (21 gms) it turned out quite nose heavy so I suggest you use fairly heavy material for this unit (much better than having a big dollop of lead on the back end). Sand both units to a streamline section.

Covering: The original was covered in white lightweight modelspan.Three coats of thinned nitrated dope plus one thihned coat of banana oil gave the covering a nice vintage light fawn patina. Colour trim was French blue, applied in a scalloped pattern.
Flying Check that the flying surfaces are at the correct angle, if the tail is set correctly and the balance point is set 3/16 in front of main spar, no downthrust should be required.Try to get model to circle to the left (both power and glide) using the trim tab. Good luck with your model. See you at Old Warden! "

Update 31/12/2012: Have changed the spelling here. Thanks to sparks59 for clarification on this. It seems this model is (curiously) called Azbug, presumably by mistake. This mistake is carried all the way through the whole article and printed onto the plan itself. The correct name is Abzug, since the original 1937 design was by Malcolm Abzug.

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