Amazingly, even during the Cold War years it was not uncommon to
see aircraft modelers from the "Iron Curtain" countries participating
in international contests. Even Commies like flying model airplanes.
Because their societies and politics were so closed and guarded,
getting information about their modeling supplies was darn near
impossible except during events where inspection could be made.
Being a generally friendly bunch of guys, the modelers would share
their designs with the Free World, and vice versa. Then, in subsequent
years the Commies would show up with equipment that was exact replicas
of ours - copyrights and trademarks held no legal weight behind
the Iron Curtain. Truth be know, most or all of the participants
were probably KGB agents (or other Commie country equivalents) engaging
in extracurricular espionage activities when not at the flying field.
This article from the August 1962 edition of American Modeler presents
an amazing collection of model engine photos and technical specifications.
Ironically (and sadly), many people today
in the U.S. are beginning to view Russia as more free and tolerant
of traditional American-type values than the current U.S. political
Iron Curtain Engines - Da? Nyet?
engines - how good are they? Let us say, right away, that there
is no short. easy answer to this question. In the West, commercially
built model motors are, in general, pretty good nowadays ... no
manufacturer can hope to survive for very long if he markets a dud
product because competition is too keen. In the Soviet Union and
satellite countries, the entire background to model engine production
is vastly different and it results in some highly divergent interpretations
as to what constitutes an acceptable product.
To understand this we must remember, first, that privately owned
model engine factories, on the scale seen in countries like the
United States or Great Britain, just do not exist in Russian and
Eastern Europe. Contest engines are built mainly by individuals
or by small groups, usually working under the auspices of an official,
state-sponsored modeling organization. Such a group may consist
of six or eight professionals, designing, building, testing and
developing prototypes and then, in due course, producing powerplants
in relatively small numbers - rarely more than a few hundred, sometimes
only a few dozen. In addition, the group may undertake other
work, such as building R/C equipment.
Typical of this sort of set-up is the model development center
at·Brno in Czechoslovakia where the famous MVVS engines are made.
The center was established in 1953 and one of its first tasks was
to produce a racing engine that would put the Czech C/L speed team
at the top of the World Speed Championships. And this it did.
Russian VIP-20 is well-made .15 with disk valve, ball
bearing shaft and lapped piston.
Czech MVVS 2.5/'58 diesel .15.
MOKI M-3 is new .36 c.i.d. stunt motor built by the official
Hungarian model research institute.
Hungarian Krizsma "Record" .15 diesel. Won FAI F/F team
championships. (drawing above)
Production of 10,000 Russian .15 c.i.d. Moscow MD-2.S's
is planned. Has many racing mill features. (drawing above)
Czechoslovakia's MVVS 2.5/1959 racing .15 with Dooling
type bypass. Note big ports in piston. (see drawing and
parts & drawing above)
Best East European stunt motor to date is MVVS 5.6; won
'58 Internats. (see parts & drawing above)
Polish Jaskolka-II diesel, made in P.Z.L. aircraft factory;
reed valve, ball-bearing shaft. (see parts above)
Hungarian V.T. 0.25, smallest Iron Curtain mill; 0.015
cu. in. disp.
The construction of less specialized types of engines, made in
large quantities for the ordinary modeler, is usually undertaken
by state-owned factories. In many cases, the factories have little
or nothing to do with the actual design of the motors, design and
development of prototypes is the responsibility of individuals or
groups and the factory takes over after the test stakes are concluded.
The factories employed to produce the engines are of many types.
In some cases they are big industrial plants, such as the P.Z.L.
aircraft factory in Poland and the Carl Zeiss optical works at Jena
in East Germany.
In other instances, established designs have been freely copied.
This is particularly apparent in Russia where, for instance, exact
duplicates of the earlier type Italian Super-Tigre G.21 0.29 cu.
in. glow motor and the West German Webra Mach-1 0.15 cu. in. diesel,
have been produced under different names.
The standard of work turned out by the specialist groups, especially
some of those operating under the state modeling institutes, such
as MVVS, or Hungary's MOKI, is usually high. This does not always
hold true for the quantity-produced factory items. In some cases
it appears that production has been assigned to plants ill-equipped
for the production of model motors to the desired standards of quality
- standards which western modelers take for granted.
In Czechoslovakia, for example, factory-made versions of MVVS
0.15 and 0.29 cu, in. racing type glow motors began appearing under
the name "Vltavan" during 1956-57. Although these engines had all
the technical features of the MVVS prototypes (ball-bearing shafts,
ultra-light ringed pistons, disk-valve induction) they lacked precision
and, as a result, failed to approach the performance of the MVVS
originals. A production of 5,000 units per year was estimated for
these engines, but it seems extremely doubtful if this was ever
reached. The Czechs then adopted a change of policy, taking on more
employees at the MVVS center and embarking on a program of limited
quantity production in the center's own workshops.
Apart from the sources mentioned, a few engines have also been
produced privately in small workshops owned by one man or a family.
Typical of these were the AMA engines made by A. Machacek in Czechoslovakia
and the East German Wilo and Schlosser engines produced, respectively,
by Willi Otto and the father and son partnership of Max and Benno
Schlosser. In the early post-war years, such outfits turned out
most of the engines available at that time.
From the foregoing it can be seen that up to the present modelers
in these countries have had to look to the research and development
centers, like MVVS, for contest-grade engines but, since the production
of such engines is limited, many modelers have to fall back on less
impressive factory-built substitutes. The type of engine available
to an individual modeler is not so much dictated by what he can
afford to pay for it, as by his ability and reputation as a modeler.
For example, in 1956, MVVS made only eight and, in 1957, only four,
of their special 0.15 cu. in. racing motors. These went to selected
Czech international speed contestants. Subsequent, less exotic,
but still above average, MVVS productions were distributed to official
clubs for allocation to top grade modelers. More recently, since
MVVS began quantity production on a small scale, MVVS engines have
been more widely distributed ... but this is the exception rather
than the rule.
Although the average factory-made model engine produced in Eastern
Europe is not up to the quality and performance of its Western counterpart,
nevertheless, there have been efforts to export some of these engines,
not only to countries within the Soviet sphere of influence and
to the uncommitted nations, but to Western countries as well. The
Hungarians and East Germans have been the most active in this sphere
with Alag, Aquila, Proton and Zeiss powerplants. The Hungarian foreign
trading organization, "Artex", placed advertisements in Western
magazines and has succeeded in selling a limited number of engines
through wholesalers in England, Australia and some West European
Up to the present time, sales of East European engines in Western
countries have been small. In some cases, importers have been left
with stocks of unwanted engines when dealers failed to reorder.
Nevertheless, there are good reasons for believing that it would
be a mistake to write off the East European model engine industry
as being no potential threat to Western manufacturers. One large
West German model company, for example, is currently selling a range
of diesel motors made for them in Hungary.
Originally, this company wanted a low-priced beginner's engine
and bids "Were invited from various manufacturers.
A British firm quoted approximately $1.70 and was thought to
stand the best chance. The contract, instead, went to the Hungarians,
who undercut the British price about 25 percent. East European quantity-built
diesels, in fact, are up to 50 percent cheaper than Western engines
of similar type. This may not be too important to the average Western
modeler who may have to pay (by the time import duties are added)
nearly as much as for a domestic product. But it could mean that
we may find unexpected competition for our products in less highly
developed countries. On the other hand, so long as we have manufacturers
such as Cox, who, by the use of advanced, highly mechanized production
methods, can turn out a better product at a lower price than the
low labor cost countries, America can remain the world's biggest
model engine exporter.
Let's have a look at some of the engines which modelers in Russia
and the satellite countries have been using lately. During the past
three or four years, we have tested upwards of a couple of dozen
different types of model engines from the East. From these we have
selected ten representative, current examples for examination.
MVVS 2.5/1959. This is the best .15 cu. in.
glow engine yet produced behind the Iron Curtain. The engine, a
development of previous MVVS World Speed Championship winning engines,
first appeared in 1959 when about twenty were made, primarily for
Czech speed experts and we secured one of these originals. The engine
created much interest and was subsequently put into limited production.
Examples have since found their way to many countries outside Czechoslovakia.
At the last major international event for FAI speed - the Criterium
of Aces held in Belgium in September 1961 - these motors were used
by Swedish, Belgian, Swiss and German modelers, in addition to the
Czech team. A few have also appeared in the U.S. and, last year,
Lt. David Cotton was clocking up to 119-mph in FAI speed with an
MVVS, occasionally hitting as high as 138 on nitro. He threw a rod
at Huntsville after qualifying to fly in the U.S. FAI team eliminations.
These performances, we might add, are just about the best that have
been recorded with an MVVS outside the official Czech team.
Designwise, the MVVS is of the classic racing engine layout with
twin ball-bearing supported shaft, disk-valve induction, a ringed,
aluminum piston and a Dooling-type hemispherical bypass. The piston
is a work of art. It has two vast ports which take up practically
all the skirt surface on the bypass side and, complete with rings,
conrod and full-floating wristpin, it weighs only 0.22-oz. In our
example, compression seal provided by the rings is outstandingly
good and the motor starts almost like a beginner's job.
Another interesting feature is the disc-valve, unusual in that
it uses a cast-iron rotor, mounted on a steel shaft drilled for
lubrication and running in a long bronze bearing in the backplate.
The engine has the same backplate and inclined carburetor as an
earlier version but this is rotated through 90 degrees to locate
the intake at the bottom. The rotor gives a conventional intake
timing of 45-deg ABDC to 45 ATDC. The exhaust and bypass timing
is also orthodox with periods of 130 and 110 degrees of crank rotation
respectively. The motor has the widely favored Continental European
.15 bore and stroke combination of 15-mm x 14-mm (0.5905 x 0.5512-in).
Weight is 5.1-oz.
On its introduction, the Czechs rated the MVVS 2.5/1959 at 0.38
brake horsepower at 18,500-rpm, a figure which put it above any
Western 0.15 available at that time. Our own tests indicated an
output of 0.35-bhp at around 18,300 on a commercial racing fuel
(30 percent nitro-methane) to which 10 percent extra nitro-methane
had been added. This was with the engine in strictly stock condition
and retaining the standard spraybar in the intake.
Moscow MD-2.5. This Russian built racing type
.15 was announced in 1960, when it was stated that it would sell
at the equivalent of about $8.50 and that a production of 10,000
units was planned over a five year period. The Moscow is obviously
based on the MVVS 2.5/1959 just described, presumably adapted to
suit the factory production facilities available. All castings are
pressure die, instead of sand castings and the engine shows a number
of production economies which, in our example, were reflected in
somewhat sub-standard construction and performance.
The lightweight, ringed piston was quite nicely made and the
cylinder liner was well finished with cleanly cut ports. However,
piston/cylinder fit was poor and resulted in extremely reluctant
starting, necessitating a castor-oil prime to seal the rings. Also,
the ball-bearings were rather a sloppy fit in their housing. As
on the MVVS, the valve rotor is mounted on a 3.5-mm shaft running
in a bronze backplate bush, but is of aluminum instead of cast-iron.
An unusual and not altogether satisfactory arrangement, the inclined
carburetor simply plugs into a tapered boss in the backplate without
any set screw or clamp to secure it. Bare weight is 4.8 oz. The
engine is available with either a spinner type prop mounting or
a flywheel for boat use.
The Moscow MD-2.5 is nominally rated at 0.30 bhp. However, the
best we could get from our example was barely over .24 using 30
percent nitro racing fuel. We also checked it against a Cox-Tee-Dee
.15 on identical props and fuels and obtained the following: 8 x
4 Top-Flite Nylon, 13,000-rpm (Tee-Dee, 16,600): 8 x 3 1/2 Top-Flite
Wood, 14,250 (Tee-Dee, 17,600): 7 x 4 Power, 15,700 (Tee-Dee, 19,400).
We accept the possibility that our test MD-2.5 may have been
a particularly bad example. Even so, it is quite obvious that this
engine is no threat to the established top contest .15's at the
VIP-20. This original powerplant takes its name
from the initials of its designer, the well-known Russian free-flight
modeler, V. I. Petukov. It is another 0.15 cu. in. disk-valve, ball-bearing
glow engine, but our example was of much superior finish and performance
to the MD-2.5.
Construction features a one-piece cylinder block and crankcase
with integral intake, the valve disk being mounted in the rear and
giving a timing of 48 ABDC-46 A TDC. The finely made cylinder sleeve,
a slip fit in the main casting, has multiple ports despite the use
of a lapped piston. The piston is unusual, having a flat head with
a curved step type deflector on the bypass side. Resultant exhaust
and bypass periods are 148 and 128 degrees respectively. The engine
has a normal type bypass passage but gas entry into the bypass is
supplemented by rectangular ports in the piston skirt and liner.
An unusual detail is the needle-valve and venturi assembly which
allows the needle valve to be installed in any one of four positions,
left or right, upright or inverted.
Claimed output for the VIP-20 is 0.38-bhp at 18,000-rpm on 25
percent nitro. The test engine did not quite equal this figure but,
on 30 percent nitro, was comparable with a Cox Olympic. Bore and
stroke are 15.2 x 13.6-mm (.5984 x .5354-in).
MVVS 2.5/1958 and 25-D. The MVVS 2.5/1958 was
the result of efforts to provide the Czech team to the 1958 World
Championships with an FAI 0.15 free-flight diesel comparable in
performance with the Oliver-Tiger. This was a twin ball-bearing
motor of which about a hundred were made, but a plain bearing version,
with minor improvements was also put into series production under
the designation 25-D. We obtained a 25-D from one of the Czech team
members at the 1958 World Championships and subsequently acquired
a 2.5/1958 also. There was little difference in performance between
the two models: both delivered near to 0.30 bhp at between 15,000
and 16,000-rpm closely approaching the performance of the stock
Quite unlike the Oliver in design, the MVVS diesel is a loop-scavenged
motor and may possibly have been influenced to some extent by the
Japanese Enya 15-D MkI which first appeared a year or two earlier.
Like the Enya, it features a large diameter shaft, a divided bypass
- and in the 25-D version a cutaway piston skirt on the bypass side.
In addition, it has a distinctive, oblique bypass port which causes
the outside edges of the port to open earlier and close later than
the center area.
Both models are well made and easy to handle. Bore and stroke
is 15 x 14-mm. The 25-D weighs 4.7-oz, 0.3-oz less than the 2.5/1958
and about an ounce less than the Oliver.
Krizsma Record K-6. The Hungarian Krizsma Record
.15 diesels were second only to Oliver-Tigers in numbers used at
the big 1960 World Free-Flight Championships, where they were employed
exclusively by the Team Championship winning Hungarians and also
by the Polish team. Two models have been built, the K-6 (with which
this report deals) and the K-8, a ball-bearing version of the same
The design of the K-6 is strictly orthodox: i.e. a shaft valve,
radially ported, plain bearing layout such as has been popular for
European diesels for many years. The standard of workmanship, however,
is of an exceptionally high level and we would rate this the best
finished engine that has so far reached us from Eastern Europe.
Die-casting is exceptionally clean, fits are excellent and finish,
inside and out, comparable with the best Western standards. The
engine uses multiple large Volume internal bypass flutes on the
pattern of the West German Webra Mach-1. On test we obtained an
output of 0.286-bhp at 14,700-rpm which is very good for a plain
bearing diesel of this size and type. Bore and stroke are 15 x 14-mm.
Jaskolka 5G-2.5 Mk.2. The Jaskolka ("Swallow")
is one of a series of model motors designed by one of Poland's best
known model engineers and free-flight modelers, Stanislaw Gorski.
It is built at the P.Z.L. aircraft plant.
The model featured is the Series 2 version with reed-valve induction
and twin ball-bearing shaft. The Jaskolka has also been built in
plain bearing and rotary valve models. Cylinder porting is again
of the Webra type just described and the major components, crankcase,
cylinder, backplate and head, are threaded assemblies, no separate
screws being used. The carburetor screws into the backplate, clamping
a 0.005" spring steel reed and can be rotated through 360 degrees
to bring the needle-valve to any convenient position. Performance
is about average for engines of this type - around 0.25-bhp-and
the motor weighs 4.75-oz.
V. T. 0.25. V.T. stands for Vella Testverek
or Vella Brothers. Andras and Geza Vella design and build the V.T.
Alag and Aquila diesel and glowplug engines in a plant in Budapest
and production is reported to be "a few hundred" monthly. The diminutive
V.T. 0.25 diesel is the smallest engine produced so far in Eastern
Europe - half way in size between Cox's Tee-Dee 0.010 and 0.020
models. It is 1-5/16" high and weighs 5/8-oz. Design and construction
follows the same general pattern as the larger V.T. diesels, except
that a cast-iron piston is used in place of the aluminum one favored
earlier by the Vella brothers. This is better, since the aluminum
contra-piston, having a higher coefficient of thermal expansion,
tended to seize in the bore when the motor reached running temperature.
A rather unusual simplification on the V.T. 0.25 is the back cover,
which merely presses into the crankcase instead of being threaded.
Kometa MD-5. This Russian-built glow 0.29 is
an exact copy of the earlier type Super-Tiger G.21 with ringed piston
and detachable front plate. Not so well made as the Italian original,
it has been quite widely used by the Russians, with minor modifications,
for stunt, speed and speedboat work. Performance varies to some
extent between individual examples but, from tests we have made,
the Russian claim of 0.50-bhp is not unduly optimistic for a reasonably
good example running on about 30 percent nitro. (This compares with
the Super-Tigre rating of 0.80-bhp at 17,500, for the original which
was a trifle exaggerated.)
Crankcase/cylinder-block, front housing and head are all pressure
castings, reasonably well produced but without any surface treatment
to improve appearance. The generously proportioned, unhardened shaft
has a 12-mm main journal, a 9-mm gas passage and is blued on non-working
surfaces. It has a big rectangular valve port, registering with
a similar aperture in the bearing, to give a quoted timing of 35-deg
ABDC to 70-deg ATDC, although the measured timing on our example
was, in fact, 25-55. The shaft runs in 12 x 28-mm 8-ball inner,
and 7 x 19-mm 6-ball outer bearings, the rear race centering the
housing in the case. The pressure cast piston has two rings and
a full-floating tubular wrist-pin. The slip fit cylinder sleeve
is well made with multiple ports cleanly cut. Bore and stroke are
19 x 17-mm (.7480 x .6693") and the motor weighs 7.4-oz.
MVVS 5.6. The 0.346 cu. in MVVS 5.6 is the most
successful East European stunt engine produced to date. It was designed
in 1957 and one was subsequently used by Josef Gabris to win the
world stunt championship for Czechoslovakia in 1958. Prior to this,
on September 15, 1957, a special hopped-up version, reduced to 5cc
displacement, broke the world record for Class II speed models with
151.6- mph in the hands of Bohumil Studeny, an MVVS employee. More
recently, at the Belgian Criterium in September 1961, Sirotkin of
Russia and Herber of Czechoslovakia, both using MVVS 5.6's and competing
against the cream of European stunt flyers and the world's best
stunt engines, placed 2nd and 3rd behind the Fox 35 powered entry
of World Stunt Champion Louis Grondal.
The remarkable thing about the MVVS 5.6 is that, except for having
a similar displacement, it is quite unlike the accepted idea of
a stunt 35. For a start it has a ringed aluminum piston, rear disk
valve induction and a ball-bearing shaft. General design, in fact,
follows that of the MVVS racing engines except for a near vertical
intake, reduced frontal overhang and more conservative rotary-valve
timing of 50-30. Construction is to the usual MVVS standards. All
castings are sand cast and extensively machined and metal-to-metal
joints are used throughout. The engine weighs 7.25-oz and has a
20 x 18-mm (0.7874 x 0.7087") bore and stroke.
The MVVS 5.6 was designed to operate on straight 75/25 methanol/castoroil
fuel because of the severely limited availability of nitro methane
in Czechoslovakia. Our engine, on a low (3 percent) nitro content
commercial fuel delivered 0.54-bhp at a little over 13,000 rpm.
It was extremely easy to handle and starting was as good as, if
not better than, the best conventional lapped piston 35's.
MOKI M-3. The equivalent of the MVVS center in
Hungary is MOKI and the latest MOKI product is the M.3, a 0.364
cu. in. stunt glow motor. The layout of this motor is generally
similar to that of western stunt 35 class engines. It uses a unit
die cast crankcase and main bearing (the latter bronze bushed) and
a mild steel cylinder with integral fins. The piston is very light
and is relieved below the wrist-pin centers. The hardened, counterbalanced
crankshaft has an ll-mm diameter journal and a moderately sized
valve port which gives 40-40 induction timing.
Claimed output for the M-3 is 0.55-bhp at 14,000-rpm on 75/25
methanol/castor. The engine has a bore and stroke of 20 x 19-mm
(0.7874 x 0.7480") and weighs 7.6-oz. Like the Russian glow engines,
the MOKI is taped to take a standard "western" size 1/4 x 32 TPI
glow plug, unlike the Czech MVVS engines which use 6- mm metric
In conclusion, it is interesting to note that while engines from
the Eastern bloc countries are seldom seen in the U.S., quite a
few American and other Western motors have been used on the other
side of the Curtain. In Hungary, especially prior to the advent
of MOKI engines, Western motors have been quite widely employed
in contests ... notably McCoy and Super-Tigre for CIL and Webra
for F IF. In Czechoslovakia, the national championships for stunt
and team-racing have twice been won with McCoy and Oliver- Tiger
motors. In Poland, SuperTigre, O.S. and Webra motors from Italy,
Japan and West Germany have been officially imported for the use
of leading contest modelers. And at the last World Stunt Championships,
the two highest placed modelers from the East, Dr. Geza Egervary
of Hungary (5th) and Yuri Sirotkin of Russia (8th) used Veco 35
and McCoy 35 motors respectively.
Russian Kometa MD-S is carbon copy of early
Italian Super-Tigre. Moscow MD-2.S has MVVS features. (see parts
Posted April 13, 2014