Thunder Tiger PRO.H RING User Manual

INTRODUCTION

Congratulations on your purchase of a Thunder Tiger model
engine. ALL the latest Thunder Tiger series engines have been
designed to combine the high performance with easy handing
and maintenance using modern CAD computer technology. Major
components of the engines are machined from the highest quality
materials using state-of-the art CNC manufacturi ng techniques,
resulting in consistently high quality and reliability.

The PRO series helicopter ring type engines are equipped with
dual ball-bearings, Schnuerle porting, one ring type piston/cylinder
assembly and two-needles automatic mixture control carburetor.

IMPORTANT

This engine will provide you with years of safe use, provided

that you carefully follow these safety instructions:

1. This model engine IS NOT A TOY, but a powerful miniature
engine that is capable of inflicting damage to both people and
property if misused.

2. Always mount the engine securely in a test stand or high-quality
engine mount. Never, never attempt to clamp your engine in
a vise!

3. Make sure that you use the suitable size engines and rotors
for your helicopter that followed the recommend of helicopter
instruction manual.

4. Make sure that the installation of the clutch/cooling fan system
on the engine is securely fastened and correctly. Unsuitable
installation will cause huge vibration during helicopter flying.

5. Do not run your engine around dirt, sand or loose gravel. Such
material can be thrown into your eyes by the propeller. In
addition, the engine can be damaged by these materials entering
the carburetor.

6. Take care to keep all loose clothing, rags, tools, etc. away from
the rotors.

7. Take care when handling your engine after running. Model engines
get very hot during operation!

8. Always operate your engine with proper ventilation. Model
engines produce toxic fumes when run in a closed room or
confined area.

SPECIFICATIONS

INSTALLATION

Engine

Mou nt your eng ine

securely to rigid engine

mount. Make sure the

mounting surfa ce are

absolu te ly flat and

parallel to avoid engine

di s to r tion (be arings,

crankcase...) and power

loss.

Dimensions

NECESSITIES

The following items are necessary for operating the engine, these

are available at you hobby dealer.

FUEL

A good quality, commercially available fuel containing 25% lubricant
and 75% methanol is recommended for break -in /run-in and

general usage. We also recommend castor oil or a castor /synthetic
blend only for use as a lubricant. Fuel con taining 5%~30 %
nitromethane and 20% lubricant is for use when more power is

required. Most fuels containing synthetic lubricants (only) are
much less tolerant of a lean run compared to fuel that contains
castor oil. If availability or local conditions force you to use a fuel

that contains only synthetic lubricant, we suggest that you keep
your needle valve set to a slightly richer setting, allowing more
lubricant to flow through your engine to extend engine life and

maintain optimum reliability. Do not use fuel containing less than
20% lubricant.

CAUTION 1

Methanol and nitromethane are poisonous and highly flammable.
Keep out of reach from small children and keep away from heat
and open flame.

CAUTION 2

Excessive heat can greatly reduce the life of your engine. Most

of the heat generated by combustion is removed via the lubricants
that are contained in your fuel, and exits the engine as exhaust
vapor. As a precaution, you should periodically remove the muffler

from your engine and visually inspect the exhaust port and piston.
If the outer surface of the piston is stained a very dark color, it
can indicate that your engine may be overheating. This can be

caused by either an excessively lean needle setting or a lack of

airflow across the cylinder and head.

THUNDER TIGER PRO.H

RING TYPE SERIES ENGINES

INSTRUCTIONS

ENGINE A

(mm/in)B (mm/in)C (mm/in)D (mm/in)E (mm/in)F (mm/in)G (mm/in)H (mm/in)

PRO-39H(R) 74.5/2.93 53.0/2.09 76.8/3.02 61.0/2.40 15.0/0.59 38.0/1.49 31.0/1.22 43.4/1.709

PRO-50H(R) 84.9 / 3.343 60.3 / 2.374 86.4 / 3.402 69.1 / 2.72 17.5 / 0.689 44 / 1.732 34.0/1.34 45.61.795

PRO-70H(R) 83.1 / 3.272 55.5 / 2.185 101.9 / 4.012 80.1 / 3.154 25 / 0.984 52 / 2.047 43.0/1.69 56.6/2.228

PRO-90H(R) 83.1 / 3.272 55.5 / 2.185 102.3 / 4.028 80.5 / 3.169 25 / 0.984 52 / 2.047 43.0/1.69 56.6/2.228

ENGINE ITEM Displacement Bore Stroke Crankshaft Practical OUTPUT Weight

NO (c.c/cu.in) (mm/in) (mm/in) Thread RPM (BHP/RPM) (g/oz)

PRO-39H(R) 9604 6.45 / 0.394 21.6 / 0.850 17.6/ 0.693 UNC 1/4-28 2,000~22,000 1.35/18,000 290/10.22

PRO-50H(R) 9605 8.27 / 0.504 22.5 / 0.886 20.8 / 0.819 UNC 1/4-28 2,000~20,000 1.75 / 17,000 405/14.28

PRO-70H(R) 9607 11.49 / 0.701 25 / 0.984 23.4 / 0.921 UNC5/16-24 2,000~18,000 2.25 / 16,000 570/20.10

PRO-90H(R) 9609 14.78 / 0.902 28 / 1.102 24 / 0.945 UNC5/16-24 2,000~16,000 2.75 / 15,000 575 /20.28

PRO-90H(R) / 9609 SHOWN

GLOW PLUG

The type and quality of glow plug used in your engine will have

a major impact on overall performance and reliability. The engine

operates best with a R/C long-type plug such as Thun der Tiger,

K&B, or O.S.No.8. Fox plugs (while of excellent quality) have a

colder heat range and may cause idle or throttle transition problems

in small engines.

BREAK-IN/RUN-IN

Because Thunder Tiger engines are precision-made from quality

materials and is a ringed engine, prolonged break-in is not required.

But, when it is new, the engine must be run in a rich condition

for at least 6 tanks of fuel to allow for proper break-in. It is important

to make sure the engine does not overheat at anytime. Also, it

is critical that the engine be run in an area free from excessive

dirt and sand.

CARBURETOR ADJUSTMENT

The Thunder Tiger PRO.H type carburetors are specially designed

for the high perfor mance Thunder Tiger PRO series helicopter

engines and provide the proper air-fuel mixture automatically for

helicopter flying at any throttle operating range.

Since the carburetor has been pre-set at the factory , large

adjustments of this carburetor should not be required. However,

under different operating conditions, minor re-adjustments may

be required. These conditions include set-up of the helicopter,

glow plug used, and weather conditions.

IMPORTANT

Before trying to adjust the carburetor, please note the following.

In helicopters, engine failure in flight as a serious problem,

especially for the inexperienced model er. It can mean loss of

control and a resulting crash.

For ensuring safe and reliable control on the helicopter flight, it

is a must that the engine keeps running and that the throttle has

quick and reliable response. Therefore, the carburetor adjustment

is very important for the helicopter and this should be done with

great care to obtain an optimum throttle response. In the helicopter

flight, the throttle response on the medium speed range with the

partial throttle opening is very important. Because, medium speed

range is widely used in the flight . On this carburetor, only two

adjustable controls are provided.

l) Needle Valve (installed in left hand side of carburetor) This

controls the mixture strength of the engine speed range from

half to fully opened throttle.

2) Mixture Metering Screw (hidden in the throttle barrel in right

hand side).This controls the mixture strength of the speed range

from idling to half opened throttle.

Please note the best mixture strength around half opened throttle

is obtained with the balanced controls of both l)Needle Valve and

2)Mixture Metering Screw.

SETTING BEFORE ENGINE STARTING

Close (turn clockwise) the Needle Valve until it stops. Open the

Needle Valve 3 turns from the closed position.

Make sure that the throttle linkage is set so that the throttle rotor

is fully open when the transmitter throttle stick is moved to full

high speed position and that the throttle rotor is fully closed when

both the throttle stick and throttle trim lever are moved to the

lowest position .

ADJUSTMENT

Following procedures are recommended to adjust the carburetor.

Adjustment low speed performance (range from idle to 1/3 opened

throttle)

1) Start the engine with the transmitter throttle stick fully down

and the throttle trim level set the neutral position.

2) Set the throttle trim lever so that the engine runs with highest

idling rpm but without engaging the clutch.

3) Increase the engine speed by advancing the transmitter throttle

stick graduall y until the helicopter just lifts up(floats) from the

ground. Warm up the engine by keeping above floating condition

for appr oximately 10 seconds then slowly reduce the engine

speed, land, and allow the engine to idle for a while.

4) Repeat above procedure several times. If the engine tends to

hesitate or stop after hesitation, the mixture at idle is not correct.

Generally speaking , if the mixture at the idle is too rich, the

engine stops abruptly with short hesitation when the throttle is

opened. On the other hand, if the mixture is too lean, the engine

will hesitate a little longer with weakened exhaust sound.

5) If the engine runs with hesitation but does not stop then try to

increase the engine speed by means of the transmitter. Try to

hover the helicopter, maintaining the altitude of approx. l ft or

30 cm from the ground, then carefully watch the exhaust smoke.

If the mixture is too rich, you may observe an excess of exhaust

smoke and will feel lazy throttle response. If the mixture is too

lean, the engine runs with higher pitched exhaust sound, without

any or very low exhaust smoke then the speed will be reduced

showing overheating tendency and the helicopter is hard to

continue hovering.

6) After you find the condition of the mixture, turn the Mixture

Metering Screw 30 degree at a time, according to the mixture,

by using a small screw driver to correct the mixture. If it is too

rich, turn the screw clockwise. If it is too lean, turn the screw

counter-clockwise.

Adjustment high speed performance

The optimum Needle Valve setting is usually 1/4~l/2 turn closed

from the starting position (i.e 3 turns open from the fully closed

position). It depends, of course, on l) the individual characteristics

of the helicopter and its engine/muffler installation, 2) the fuel used

and 3) atmospheric conditions.

The Needle Valve should be gradually closed until the highest

performance is obtained in flight at full power.

However, take care not to close the Needle Valve to a too lean

setting and risk overheating the engine, in the pursuit of maximum

performance.