| REG'S SIG CITABRIA
- THE LAST WORD
| My SIG
Citabria, now christened Annette
after my lovely and youngest daughter, has now been
flown and I am very happy to say she performs very well. The kit
recommends a ·46 2-stroke or a ·60 4-stroke, and those of you
who have followed its (long) building progress will know that I
fitted the ·60 RCV 4-stroke engine. Gordon kindly undertook the
initial flight and expressed the view that there was certainly
plenty of power there, and this was soon confirmed in the very
short take-off run with the engine at full throttle. The plane is
extremely stable and remains steady even in fairly changing and
turbulent air conditions. She can come in nice and slow and
steers well on the ground. |
Looks
good to me, even without cowl and spats! |
One wing strut came detached from
the fuselage fixing on the maiden flight and for the second
flight, a week later, I had slipped small lengths of fuel tube
over the nylon clevises to try and ensure that they stayed
firmly closed. I loved the take-off as she lifted off at a nice
gentle angle and stayed rock-steady as she climbed, despite a
bit of gusting side wind. I am not yet into aerobatics, so my
flight was just a matter of gentle circuits and
figure-of-eights, and the plane was a delight to fly. All was
well until a cry went out that a wing strut had come adrift,
despite the retainers. To play safe, I handed the plane over to
Gordon's safer hands and by the time he brought it gently down,
both wing struts on one side of the wing were adrift from the
fuselage but still attached to the underside of the wing, the fuel tube grips having slipped back over the nylon
clevises.
As mentioned before, the business
of rigging the plane is somewhat tedious, with the wing struts
being screwed up into the wing every time with very small screws
and the fuselage end being anchored (?) by the use of clevises
through small aluminium plates fixed into the fuselage. I was
concerned about this repeated screwing in and out of the wing
every time I take the plane to the field and
decided to modify the wing fixing to avoid this necessity, as
well as replacing the nylon clevises with metal ones with a much
more positive closure, plus the fuel tube grips . The
modification is clearly not a scale approach, but it looks o.k.
to me and is certainly a great improvement in terms of security
as well as resulting in a faster and less fiddly rigging. My wing-fixing
modification was to screw and epoxy four Flair closed-loop adapters into
the wing, having put a flat face on each side of the adapter and
slightly enlarging the little hole to allow a metal clevis to be
fitted. The wing struts can then be disconnected at the fuselage
and the threaded rod simply run
out of the clevis under the wing to remove.them - they
could be left fitted to the wing as they will pivot
back to lie flat along the wing, but they could be prone to
accident if left attached, I fear.
 |
 |
 |
 |
| adapters |
flats |
clevis
fitted |
wing
fixing |
Quite a bit of interest has been
shown in the RCV engine. Once set up and run-in in accordance
with the manufacturer's instructions, it is certainly a good
starter and sounds rather interesting! It does run extremely
hot, and on its first run with the cowl fitted it was
immediately evident that cooling was far from adequate. The heat
of the exhaust pipe actually started to melt the ABS cowl where
it is close to the pipe, and the whole of the cowl became far too hot to
touch. Subsequent flights have therefore been made without the cowl
fitted, but I have now greatly enlarged the air exit space at the
lower back of the cowl and wait to see if air flow has been
improved sufficiently to solve the problem. The manufacturer's
recommended fuel is Duraglo 10, but I was initially running on
Irvine Contest 10 which I thought met the specification, but
since Duraglo 10 is actually stated to be particularly cool
running, I have now switched to that.
Because of the 2:1 gearing of the
RCV engine, a larger-than-normal prop is required - a 16 x 12
being typical - so before thinking of using this engine I would
suggest you check that it will suit your model in terms of
ground clearance and appearance - I realise that you don't see
the prop once the thing is running, of course, but it might be
important to you. A remote glow lead
is also an essential on this engine, and you may therefore find
it essential to be able to turn up the current to the plug a bit
before you can obtain sufficient glow - my control panel did not
have that facility, so I have had to buy a panel specifically for
this model! There is also a tendency for the exhaust pipe
nut to loosen, despite being done up really tight, so I
took the advice of another club member who has this engine and
re-fitted the exhaust pipe using a piece of card as a gasket
where the pipe fits into the engine proper. However, this has
not proved 100% effective - there's too much give in the card, I
think, so I'm trying again without the gasket but with the thing
tightened even further by someone more confident than me as to
how tight is safe without risking stripping the
thread!
|