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By Graham Woods |
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This QUARK balsa model comes as a part-kit, a design by Fred Marie whom I believe is a Frenchman; the model certainly looks like a French VTPR type with a bulbous front end. The kit is all wood except for a GRP bellcrank. All the parts for the fuselage, wings, rudder and elevator are laser cut from balsa and lite-ply. However, you will need some sheet balsa and wing tubes and dowels plus hinges, clevises etc. to complete the model. The two plans and instructions supplied refer to different iterations of the model, I believe, which can be confusing as one recommends a 1m carbon tubular spar in each wing while the plans only show a shorter carbon wing dowel tube with spruce or balsa spars. I balked at the cost (£30+ inc.pp) of a 2 metres of carbon tube and carbon rod as wing dowels so I chose 10mm aluminium tube and a short piece of 8mm diameter carbon rod for the main dowel with a smaller pieces of 6mm carbon rod and ally tube for the locating dowel which I already had.
The wing construction is straightforward, and because the wing ribs are laser cut, the parts lock together tightly to make a light but seemingly strong wing. The wing can be part or wholly sheeted. The ailerons and wings are built-up separately and, like the fuselage and tail pieces, have lightening holes to save every gram. The finished 2M model can come out as light as 1.2kg but I had no way of knowing its final weight until it was balanced. I intended to use a mix of Solartex for the fuselage and transparent film for the surface covering, I already had servos for the two ailerons, rudder and elevator (HS82MG for the wings and HK* GoTeck) from other models. I considered using a pair of Samsung 18650 or 4 Eneloop Pro cells for the power supply, it depends on the balance and CG; I chose a new cell (to me) as it happens.
FUSELAGE In between cutting, gluing, pinning and waiting the second wing panel, now going faster after the first one, I removed the parts for the fuselage and laid them on the plan. The fin and rudder fit nicely and, as you can see, the fuselage is a bit of a jigsaw puzzle of ply and balsa presumably because the parts need to fit in a certain size box for the Irish post. All straightforward and with the massive plan on the floor, it looks easy to assemble and it is light. As I build, I am thinking this 2M model could come out at under 1kg. I did make one modification to the original model and that is in the nose. The nose block is made by sandwiching together the eleven pieces of balsa and ply supplied and then sanded.
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No
sorry, not this Ferengi with a lust for profit and Gold-Pressed
Latinum, nor any one of the six types of sub-atomic particles known
as Quark flavours; up, down, strange, charmed, bottom and top. In
fact, this Quark flavour, the 2M, is a lightweight aerobatic soarer
for VTPR* or close-in slope manoeuvres from Fred Marie in Ireland.
WINGS
Both the wing and tailplane are
built upside down and the ribs have lugs to support the inverted
surfaces as they are built, these are cut off later when the topside
of the wing is sheeted. Aiming to keep this model very light I chose
a balsa spar with vertical double shear webs each side of the spar
for the wings, the wing dowel is 8mm carbon tube in a 10mm aluminium
tube. One wing panel done
(and now up the right way) it just needs a little sanding then the
HS82 servo can be installed and the panel covered with film. There
are no flaps on this model only large 3” wide strip ailerons.
Designed with a built-in chamfer the leading edge of the aileron
really means that the wings have to be tape hinged on the top
surface. I chose to use Blenderm tape which, primarily
intended for skin wounds, is very sticky and quite flexible. This tape is
available from many pharmacies I should think, although I bought
mine from HK. The two panels came out at just 172g each
before final sanding, servos and covering which bodes well for a
lightweight model. 
