Mvvs 152 IRS TWIN SPARK, 152 IRS Operating instructions

Operating instructions

MVVS 152 IRS No: 3011

MVVS 152 IRS Twin Spark No: 3011TS

Before using the engine, please read these instructions carefully.

Congratulations on choosing the gas engine MVVS 152cc.
MVVS 152cc has been designed and manufactured for propeller-powered radio-controlled
model planes. It is able to meet all of your expectations of an acrobatic racing engine.

Technical specifications

Bore 48 mm RpM range 1000 – 7500 RpM
Stroke 42 mm

Version 1.3

Weight of complete
engine without ignition*

3530 g Fuel

Unleaded 95-octane

fuel

Weight of ignition unit 270 g Lubrication

* Some manufacturers state the weight of incomplete engines. The value in the table above
stands for the weight of a completely assembled engine, including the spark plug, carburetor,
drive washer and prop screws.

Safety precautions

1) Never use the engine for any manned vehicles.

2) When operating model planes, always follow the rules and laws in effect in your country.

3) The manufacturer declines all responsibility for all damages arising from the operation of

models and other appliances driven by MVVS 152cc engine.

4) Use always original spare parts.

5) Never tamper with the engine construction.

6) Before each flight check that all the propeller screws are tightened up and in good

condition. If you use a spinner, check that it is tightened up too. When mounting the
spinner always follow the assembly instructions.

7) Periodically check that the engine is firmly fixed to the engine mounts. Never start a loose

engine!

8) Always use a balanced propeller! Always replace the propeller when damaged!

9) Make sure that no part of your body intersects the plane of the spinning propeller.

10) Always wear close-fitting, well-fastened clothes when starting or operating the running

engine. Never wear loosely hanging clothes (tie, scarf, etc.).

11) Never try to stop the engine by any part of your body.

12) Always stop the engine either by turning off the ignition switch or by completely closing

the carburetor throttle valve.

Oil with petrol in

mixture 1:40

13) Before starting the engine always make sure that the model is safely fixed in place and

cannot start moving.

14) Fuel is combustible and therefore must be kept in an enclosed container at a safe distance

from the engine when it is running.

15) When preparing fuel carefully follow the manufacturer’s or dealer’s instructions.

16) Small objects must be kept at a safe distance from the engine when it is running. Never

throw any objects towards the spinning propeller.

17) Be careful in choosing the location where you wish to start the engine. Avoid dusty or

sandy areas.

18) Start the engine in well-ventilated areas only. Never start the engine indoors.

19) When starting the engine make sure that bystanders, especially children, are at a safe

distance of at least 10 m.

20) The engine power output makes it possible to fly big models. Mal-operation of such

models may cause serious damage. Start using the MVVS 152 cc in model planes only
after you have mastered operating smaller models.

Selecting a suitable propeller

It is usually the case that propellers of the same dimensions coming from different
manufacturers are not the same. Oftentimes not even propellers of the same dimensions
produced by a same manufacturer are not the same. The engine power is best utilized when the
propeller dynamics curve and engine power curve (revolutions/power output) intersect in the
area of the engine top power output. Unfortunately, no propeller manufacturer provides this
information. Engine power output is also a variable quality. It depends above all on the
silencer used and can considerably vary. The situation is further complicated by environmental
parameters (temperature and atmospheric pressure in particular): low temperature and high
pressure increase propellers’ input requirements by 20% in comparison with input at hot
weather.

Suggested propeller dimensions: two blade: 30x12, 32x10-12

three blade: 29x12 N
These values are only approximate and may vary with the factors described in the previous
section, as well as with the type of the exhaust system used.

The MVVS 152 is designed for the power maximum by 5800 – 6300 RpM (according the
exhaust pipe used). If this maximum performance is needed, choose the suitable propeller so,
the engine reach these speed on the ground (in fact slightly lower; depends on the unloading
the propeller in air in accordance to reached speed while flying)

We do not recommend use of propellers, which allows turning the engine on the ground more
as 7000 RpM.

Fuel

Always use unleaded 95-octane petrol mixed in the proportion 40 volume units of petrol to 1
unit of Mobil Racing 2T oil. If necessary, quality brand-name synthetic oil intended for
racing two-stroke engines can be used too.
For running the engine in, please use MVVS Racing 2T oil that comes with the engine. Mix it
in the proportion 30:1.
Never use inexpensive oil developed for garden appliances or synthetic oils intended for the
operation of methanol model engines. The manufacturer declines all responsibility for all
engine damages arising from the use of low-quality fuel.
Store fuel in containers designed for this purpose. Do not use mixed fuel older than 90 days.

Assembly

The engine is fastened to place by four holders built in the rear cover. The engine can be
mounted directly to the firewall or an assembly kit can be used (special accessories). Use
screws M6. If you decide to fasten the engine using flexible motor mounts, always choose
parts with enough solidity and strength. Make sure to secure the screws against loosening and
regularly check that they are tightened up and in good condition.

Since air is used to cool the engine, sufficient air circulation under the cowl must be ensured.
Never forget about hot air outlet – which must be higher than the intake one. Gas engines heat
up to higher degree than methanol one!

Do not forget that the engine needs oxygen from the air to be able to operate. Therefore ensure
access of air to the engine intake as well. Caution: intake of warm air from beneath the cowl
may cut the engine power output.

For fuel supply use the hose delivered only, this diameter ensure the sufficient fuel supply in
each turn and minimize the flow resistance. Use of the smaller hose can cause engine turn off
by the turning with high G-forces.

Caution! When mounting the engine in the model use seals to protect all openings and
prevent the pollution of the engine’s inside with sawdust, residual abrasives etc.

Exhaust

Use only factory-made exhausts pipes designed for this type of engine. Preferably MVVS
exhaust system, which also guarantees the announced power output. The manufacturer
declines all responsibility for all engine damages arising from the use of improper exhaust
systems.
When mounting the exhaust follow the manufacturer’s instructions. Make sure to secure
sufficient cooling of the exhaust.