Motor Cyclon

Motor Cyclon 061

by Chris Murphy, Auckland, NZ

Free Flight Quarterly Nro 9 October 2003

The Cyclon 061 has become the dominant F1J engine worldwide over the past few years, due to a number of reasons-it is readily available from several sources, produced
in reasonable quantities-unlike many of the first and second generation F1J engines. It is of superb production quality-has good spares and accessories availability, and it sets new standards of performance for F1J engines.
The Cyclon 061 is manufactured in Russia by Alexander Kalmykov, already well known for his innovative and high performing 2.5cc F2C and F2D combat and team race engines-which have been around for about a decade. (Ref.1) The Cyclon 061first went into production in 1997, initially being known as the 06 Eagle (Ref.2) evolving through the 06 Top, Top-2, Top-3 to the currently produced 06 Top-4 version. The initial designs-Eagle 06
and Top 06 were not entirely successful and were quickly replaced by the Top-2 and subsequent variants. Top-2 is a ¾ left rear exhaust, Top-3 a rear exhaust and Top-4 a ¾-
right rear exhaust version. 049 and 051 variants also exist, but are externally virtually identical to the 06. There are occasional minor differences from production batch to batch.
Production is currently 200-300 engines per year, produced on CNC machinery at the local Aviation Engineering College in Novosibirsk (Ref.2)
The bare engine weighs 65.6 g, with plug, and the special Cyclon single blade prop adds a further 11g if used .
Now, looking at the engine in more detail, the Cyclon 06 is based around a very intricate and well detailed investment cast crankcase casting (Fig.1) Bore and stroke (nominal) are 11.2mmx 10mm, and the engine uses AAC piston/liner technology, which with its light investment cast crankcase accounts for its very light weight compared with some of the second generation F1J engines.
The stripped engine is shown in Fig.2 and the working parts in Fig.3 –note in particular the massive crankshaft with its vast induction area, and the extremely thick-walled cylinder (15mm OD), with angled transfer passages machined in. This allows a simpler crankcase casting and easier machining, since there are no interrupted holes. It also allows better support for the liner, leading to less thermal distortion. Piston and rod are fairly conventional,Fig 3 shows oil holes in the piston gudgeon pin bosses, and the crankshaft also has an oil hole in the crankpin to assist
forced lubrication of the big end.
The cylinder head, like many Russian combat engines screws into the casting, and retains the slip fit liner (which itself is pinned to prevent rotation when screwing down the

head). The combustion surface is nearly flat, but with a series of fine radial grooves machined
into the squish band creating a spiral pattern intended to turbulate the mixture for smoother combustion. Also, note that the fitting of the plug expands the head, and damage will result if the head is removed with the plug still fitted.
The glowplug should always be removed first before unscrewing the head. In any case, it should only be necessary to remove the head to adjust head clearance by means of 0.04mm/0.0015in steel head shims. Head clearance ranges from 0.2-0.4mm, depending on nitromethane content, typically 0.2mm for 80:20 FAI fuel and 0.35-0.4mm for 40% nitromethane fuel. Mounting is radial only, with a 4-point fixing using the integral rear mounting flange, which at 27.5mm OD, is sized to match the most common F1J sized composite tubes (e.g. Oliver and Monks tubes) The vestigial beam mounting lugs on the engine are intended for mounting accessories such as a remote shutoff, and/or a bladder fuel switch for starting.
With a nearly 6mm ID venturi and a vast induction tract, the engine is intended for operation only on a pressure system, a bladder or pacifier being the most useful. NVA is
an interference fit, and can be fitted either side, though most F1J users will have the needle on the RHS of the engine. The engine comes fitted with a typical Russian ‘wheel’ type short needle assembly, threaded 3x0.35 metric.

Performance

It is claimed that the engine will produce 0.7 BHP at 40,000rpm, but this is assumed to be on a pipe, and if achievable would be on tiny propellers of about 4” dia

meter,
which are impractical for F1J use. There is plenty of anecdotal evidence about the engine’s performance, but little verifiable by hard data. Certainly most users report performance
in the 28,000-32,000rpm range (depending on fuel) on typical F1J propellers. Few if any appear to be using the single bladed Cyclon prop (155x50) developed for use with the engine. Only one brief test report on the engine has been published to date, in the UK magazine ‘Model Engine World’ (Ref.3) and this did not use a dynamometer, but used calibrated propellers, and due to the limited number of these, only one was used, an APC 5.7x3, which the test engine turned at 29,000 rpm for an estimated BHP figure of 0.5 BHP. It should be emphasized then that this is merely a ‘spot test’ figure, but does give an indicative figure for the amount of power available at the sort of rpm figures used for F1J.
I would prefer to have seen rpm and torque figures for a number of suitable props however before accepting such a figure as typical. In reality, power could vary as much as +20% of this nominal figure.
Clearly the engine produces more power than the previous best performing examples, which as detailed in earlier parts of this series were capable of outputs of around
0.35BHP, so it is not unrealistic to expect a figure of around 0.4-0.45BHP, depending on fuel, but until more detailed dynamometer analysis is conducted, such figures for the Cyclon 06 remain speculative.