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Full review of Adrenaline published in Silent Flight available 27th March 1998
The Adrenaline is the third in a line of kits from Purbeck Sailplanes, the Swanage
based manufacturers of the Grafitti and ASW27.
I first saw the Adrenaline last summer whilst the prototype was undergoing flight
testing and on the strength of its looks and the already well established Purbeck
quality I ordered one there and then. It must be said that I already had a Phoenix
Model Products Stiletto so the Adrenaline would have its work cut out to impress me
especially since the Adrenaline costs nearly twice as much as the somewhat cheaper
Stiletto.
Four months later and I was very pleased to be the recipient of one of the first
Adrenaline to come out of the Swanage workshop. Needless to say I was not in the
least bit disappointed by the quality of the final design.
The wing is a one piece unit with a carbon fibre trailing edge and KVHS ailerons.
This is a system seen on some expensive European kits and consists of a layer of
kevlar cloth under the veneer in the area of the aileron hinge. When the ailerons
are routed out the kevlar cloth then forms a totally slop free hinge that requires
no further work. This hinge has to be seen to be believed - excellent.
The fuselage is finished in epoxy glass cloth and has a separate nose inner and
nose cone. The nose inner is ingenious in its design incorporating two ballast tubes
which can easily be loaded by sliding the nose cone off, similar to a mini-F3B model.
The tail parts, wing tips and rudder are cut to shape from a balsa/ply/balsa sandwich.
This is my only reservation as it does mean the tail parts are a little heavier than
they might be and as a result the model requires quite a lot of nose weight. Having
said that it does enable the trailing edges of these parts to be finished to a razor
sharp edge, and weigh t is perhaps not too much of a consideration with a model
featuring RG15 wing section that is built for one purpose - speed.
Final items are a a pair of obeche leading edges, a bag of accessories, and all the
push rods and other parts required to finish the model.
Construction was simple following the excellent, well laid out instruction book.
The wing was prepared first as this could then be used to line up the all-moving tail-
plane. A small departure from the instructions was the decision to try and keep the
aileron linkages internal if possible. This was not quite possible but using a pair of
horns manufactured from PCB board and a pair of Irvine engines Topaz mini-servos the
linkages are only just proud of the surface. Incidentally the kit comes with a pair
of plastic screw on horns that in my opinion have no place on any model let alone a
fast racer. This is a personal preference, many others may think they are suitable.
Shaping the tail planes and rudder was a quick and easy job. Fitting the all-moving
bellcrank for the elevator was slightly more trick but was soon achieved thanks to the
indents moulded into the fin. I used an arrow shaft as the pushrod rather than the
supplied dowel and used the supplied snake for the rudder. The nose inner was epoxied
in along with the two ballast tubes (available as extras) and the nose cone fitted
perfectly with no further adjustment being necessary. No mention is made in the
instructions as to how to keep the ballast bars in place so a hole was drilled in the
keel to a llow a dowel to be passed through to secure them. Two more Topaz servos were
used in the fuselage on rudder and elevator.
The model was finished in 3 oz glass and epoxy resin. Although the model is strong enough
to be covered in film, I prefer the durability of a glass finish. The fuselage was primed
and painted using car cellulose paints.
The model was balanced and the lead was glassed into the nose.
In true review style as soon as the kit was finished the weather turned absolutely
atrocious. Eventually the wind turned west allowing a few tentative flights to be made in
what could only be described as marginal conditions. Despite this Adrenaline showed no
vices even when slowed up. The stall was straight with no sign of the wing dropping that
blights the slow speed handling of my Stiletto.
Subsequent flights in stronger lift have shown it to be extremely fast. It is difficult
to say but it seems quite a bit quicker than the Stiletto. The handling is certainly more
friendly and the provision of a rudder makes the model much more versatile. Turns using
coupled flaps are extremely tight with very little loss of speed. I have moved the CofG
back slowly from the position recommended in the instructions and the handling has now
become much more neutral. Ballast handling is easily achieved by removing the nose cone
and although I have not yet had the opportunity to fly it with ballast I am sure this
will present no problems.
In conclusion, I am extremely impressed with Purbecks latest offering, the design is
excellent, its flying qualities are faultless and the manufacturing quality is second
to none.
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STOP PRESS: Adrenaline is soon to have a V-tailed partner called AdrenalineV.
E-mail:Purbeck
Sailplanes for further information
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