Using the Aeroclub Biplane Assembly Jig
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Background
For a quick look at what it’s all about, see my article in the
December
2005 IM.
Usage
To see how it worked out in anger I took a number of models in the two
commonest scales, in injection molded plastic, resin, and a vacform.
  To
begin where I stopped last time, I finished off the assembled but not
glued, injection molded Blue Max DH4 in 1/48th . This proved most instructive.
Once everything was aligned and checked against plans it became obvious
that the tailpane and radiator were too far out of alignment to live with,
so I took them off and reset them. The top wing centre section was also
off, so I removed it and (with the outer wing panels pushed onto brass
wire pegs) reset it in the right place. It was then a simple matter to
glue the wings in place, and spring the interplane struts into their holes.
The whole assembly was rock solid so I left the model in the jig while
rigging it. There was plenty of room to manoeuvre around the jig parts.
So, for a model of this size and scale the jig performs well.
Next I tried two 1/72nd Bristol fighters, an injected one by Pegasus
and a vacformed one by Libramodels. Each fuselage had the undercarriage
and lower wing added before I got the jig.
 For
the Pegasus kit I followed the standard procedure layed out in the jig
instructions, first securing the jig uprights at a suitable spacing against
a datum line, using double sided tape. I then set the gap and stagger
with reference to the Windsock Datafile plans and a pair of dividers.
The model was set in place and centred, the top wing placed and squared
up, and all dimensions double checked. There’s a lot less space
in this scale, especially with double bay struttery, so I started with
the cabanes then moved outwards until all struts were in place. Again,
the whole assembly was quite stable as shown by the aerobatic photo. I
could reach to do the incidence wires but needed to remove the model in
order to do the rest.
The vacform was the same, except it all flexed a bit too much at first,
so I added the inner interplane struts before adding the cabanes.
Conclusion? Well, again, it works as advertised. You should have no
trouble with something as small as a Sopwith Pup. I’ve set up a
Spad 7 just to see if everything was accessible and it was fine (no photos
because the model was not ready for permanent final assembly).
  Feeling
cocky by now, I quickly assembled a resin 1/72nd Martinsyde Buzzard. Perfect,
I thought. No problems with any of it, except that the top wing (which
I’d had to put some dihedral into with hot water) had slacked off
until it was nearly flat. I used a bit of pressure to get everything to
meet up okay and glue it up firmly. Great. Until, that is, I released
it. Booiing! I’d overlooked the elasticity of the lower wings, which
adopted an immediate and pronounced anhedral as the top wing straightened
out again.
Moral – be very sure of the qualities of the resin you work with,
and if you’re going to rely on heat-treated parts to keep their
shape, don’t. I’ve fixed the model by removing the top wing,
making new struts, sawing the top wing panels free of the centre section,
and re-fixing it all. This is obviously not a fault of the jig, but of
my use of it. No photos of the disaster, it’s just too embarrassing.
 Finally,
testing the limits of what will fit, a resin Copper State Models 1/48th
Gotha G.III. First I set up the jig as before, but located it close to
the most stable point in the assembly, the nacelles. This time I screwed
the jig in place because the only way to stop the wings from sagging is
to fix it in the desired attitude and then rig the landing wires so that
the weight is hung from the cabanes. This means flinging the thing around
while in the jig, which could get hairy if it was loose.
The photos show the top wing in place, with the front struts pushed
into the front holes and the rear ones held in place against their holes
by the weight of the wing. At this point I marked new holes for the bottom
of 3 of the rear struts, which I hadn’t put in the right place to
begin with. Then I removed the wing, drilled the new holes, filled the
old ones and tested again for fit. I raised the wing tips to the desired
level with a couple of spare stands from the jig set. Then I drilled out
the rigging holes, finished off everything that would be hard to get at
later, and fit the wing in place. After gluing in the interplane struts
I measured up and installed the cabane and nacelle struts, then simply
measured the lengths for the rigging with dividers and cut some (about
12 feet, actually) ceramic wire to length. Once secured with superglue
I finished off the control lines and added the remaining fiddly bits.
I did invert the whole circus once, and no elephants dropped out.
Finally, after leaving the lot for a few days to set solid while my
nerves settled down I removed the model from the jig and added the props.
I’ve kept it on the shelf for 2 weeks with 2 markers set beside
the wing tips, and they haven’t drooped at all.
Conclusion
 Very
simple. I’m very pleased with the jig. It works as advertised, can
work okay with a small model, and is a great boon with a larger one. It’s
endured being dropped a few times and I haven’t even managed to
loose any of the nuts and bolts yet. My thanks to John Adams for a fine
product.
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