To Supertigre Prop Chart and dimensions
Text colour for my own added notes
Last edited may-4-2000
These
notes are written for the guidance of both beginners and experienced modellers
to get the best out of their Super Tigre engines. These are high performances
top quality motors manufactured in a very modern plant situated just outside
Bologna in central northern italy. This plant, which is highly mechanised with
the most up to date production plant, is exclusively devoted to the manufacture
of model engines from .11 cu. in. (1.7 cc) to 3.60 in. (60 cc). These motors
have appeared in international contest results, national competitions and local
events since the 1950s and regularly appear in the winners circle where ever
model engines are used.
FOR
THE BEGINNER
In
glow plug engines the combustion is ignited in the cylinder by the glow plug
located in the centre of the cylinder head and in order to start the
semi-continuous process of ignition a battery of between 1.2 and 1.5 volts must
be connected in series with the platinum coil inside the glow plug. The electric
source should have sufficient current to ensure a steady orange glow to this
element and is readily seen if looking through the exhaust port located on the
left hand side when facing the propeller with the silencer removed. Combustion
is caused by both the heat of the element and a catalytic action between the
fuel and the platinum wire. The motor will continue to run once started as long
as fuel and air are present.
INITIAL
RUNNING
Whilst bench running is not essential with Super Tigre engines, a brief
bench run is useful to familiarize the modeller with the effect of the controls
and to start the running in process. The engine should be firmly bolted to a
stout piece of hardwood or plywood which has had a <<U>> shaped cut
out just the width of the crankcase beneath the mounting lugs and machine screws
1in. (25 mm) long and fitted with washers and nuts used to bolt the motor down,
The size of these screws should be the maximum diameter that will pass through
the mounting holes, The piece of wood should then be fixed to the work bench so
as rigid as possible. Ensure that there is adequate clearance for the propeller
and that no loose items are on the bench that could be blown or vibrated into
the propeller disc.
The
workshop should be well ventilated, as carbon monoxide or
Methanol poisoning could result
from the exhaust fumes.
A fuel tank containing the recommended fuel should be fixed so that the
fuel outlet is approximately the same elevation as the needle valve. A fresh 1.5
volt battery of 3 ampere hour capacity or a 2 volt wet cell accumulator with at
least 10 ft. long leads (the surplus length can be neatly taped around the
outside) should he provided. Fit the propeller so that it is coming on to
compression at the 2 o'clock position. The size should be selected from the
chart on the side,
Set the needle valve about 2 1/2, turns open from the fully closed
position. Prime the engine by placing a finger over the air intake and flipping
the prop counter clockwise three times, also squirt a few drops of fuel on top
of the piston through the exhaust port or through the plug hole if the silencer
is fitted. This is only suggested for the initial start up for the beginner who
may not have developed a sufficiently vigorous flick to get the fuel charge on
top of the piston. Once the motor has been initially run it should not be
necessary, In any case once in a model it's easy to invert the motor for a few
seconds to obtain the same effect. Turn the propeller over twice to clear any
excess and now connect one battery lead to the plug centre terminal and the
other lead anywhere on the body of the engine. A proprietary grow plug clip of
the clothes peg type is available from your dealer. A couple of smart flicks
counter clockwise should now set the motor running if only for a short burst, If
the motor fails to fire and run, check that the plug is glowing by looking into
the exhaust port. if it runs for a few seconds and then stops, open the needle a
further 1/2 turn, re-prime and try again. You should see the fuel in the feed
pipe move when running on the prime. Just remember, if the plug is alright and
fuel is present, then the motor is sure to run. if only for a short period.
A
Due to a unique production process, recently introduced by Supertigre,
the previous pinching at top dead centre is no longer so apparent.
Some modellers have been excessively cautions and returned motors under
guarantee since the motor felt tight when plug removed. Please note that after
about one hour running a smooth feel will result and it is not necessary to
return until the length of running time has been exceeded.
X40
PYLON
This is speciality racing motors with a very high performance on standard
or hot fuels. Fuel draw is weak due to the very large air intake venturis used.
Pressure fuel systems are essential both for bench running and in the model.
These motors are provided with a pressure nipple which is included in the needle
valve package in the hox. This nipple should be fitted in place of the top left
hand back plate fixing screw when viewed from the rear, a piece of fuel tube
connects this pressure point to one of the tank vents. The remaining vent should
be seated after filling. A small exhaust prime is best and a fast start obtained
if flooding is to be avoided.
Alternatively, pressure tanks of the pen bladder type can be used without
the pressure tapping.
ALL
R/C ENGINES
All Super Tigre R/C engines are now fitted with MAG series throttles
which are easy to adjust, reliable in use and capable of very low tickover,
combined with good pick-up.
Fig. 1.
|
The carburettor has two needle valves fitted- |
To
set up this carburettor it is useful to have a short piece of clean fuel pipe
handy to blow through. Firstly, the idle needle has been factory set and should
only need minor adjustment for correct setting. So don't loose the original
setting before running. The low speed setting is controlled mainly by the
throttle stop and not the idle needle, which is only used to set the mixture.
It is best to adjust either the throttle stop or servo travel in the slow
position, so that the amount of opening is approximately the diameter of a
modelling pin. Now fit the fuel tube to the fuel inlet nipple and set the high
speed needle 2 1/2 turns open from the fully closed position. Now close the
throttle and whilst gently blowing through the tube, establish the setting of
the idle needle where air just starts to escape.
The correct idle setting will now be 1/2 turn open from this point. Bear in mind if you change the position of the throttle stop, you will have to reset the idle needle. Use very slight adjustments at a time (1/16th of a turn or less for final adjustment). As a check on settings, if you, whilst still blowing through the tube, open the throttle, you will find a rapid change in air flow when the arm has moved about 15 Deg. from the slow position. When pinching the fuel line with the engine at idle, the engine should first run a bit faster before slowing down because of fuel starvation. In cases where poor transition occurs when opening throttle, a variation in the mixture strength can be obtained by rotating the fuel inlet spray bar so that the fuel pipe nipple is pointing at the front engine fixing hole in the mounting lugs. This rotation brings the slit in the spray bar towards the front and will richen the transition mixture and vice versa. This rotation is only documented in this series instructions, and is omitted in later versions. It seems that clockwise rotation slightly richens the transition and anti-clockwise rotations leans the transition. Sometimes it works, but not all the time; I never used it and point the nipple at the rear of the fixing lug.
We recommended the use of idle bar plug on R/C engines and
the cold type elements suit these motors best.
The situation you are trying to achieve is to have a normal mixture
setting at the desirable idle r.p.m. Don't use the idle needle to make a
deliberately rich mixture in order to slow the tick over. If you need to reduce
the idle, then close the drum further and readjust the mixture by unscrewing the
idle needles lightly.
GLOW
PLUG FUELS
For the USA market RO.GO fuels is highly recommended for Super Tigre
motors in various nitromethane contents. These fuels contain di-ethelene glycol
based oil without any anti-corrosion inhibitor. It is therefore recommended that
when storing the motor for a period longer than two weeks that a shot of 3-in-1
oil is injected on to the piston cylinder and through the carburettor before
putting away. This fuel will keep your motor free of lacquer or varnish on the
working parts.
For the British market, with very low nitro contents, we recommend the
use of castor oil based fuel with the addition of some Ucon oil to reduce
lacquer. A good home brew is 8 parts methanol, 1 part pure castor oil, 1 part
Ucon LB1145,to which add 5% nitromethane plus 1 fl. oz. per gallon acetone or
ether to act as a catalyst.
There are several differences between the Italian, English, French and German text as to oil and Nitro content, leaving lots of room for experiment with nitro even up to 80% for racing with the X-engines.
TIGER'S
PAW MUFFLERS
The new Tiger's Paw muffler is of the latest generation of such device.
It is very similar to the best tuned pipe in performance yet it's dimension and
weight are much reduced.
One of the secrets in this muffler design is that it allows you change
the elbow length without changing the resonating volume. This makes tuning such
a system much easier.
A muffler of this type also permits one to use larger props (greater
diameter) than usual and this also lowers the noise level.
FINAL NOTE
Model flying can be dangerous so your motto should always be <<Vola
cum cura>>- fly with care.
Under no circumstances fly U/C models under or near high tension wires
(induction danger)
