New LOWER prices on RCV! In keeping with our competitive pricing policy and with the changes in the exchange rates we are reducing the prices on the full line of RCV engines. See the pricing page for details.


58 and 91 CD Features

  • RCV Rotating Valve Technology
  • Ultra Low Profile
  • 1:1 Output Gearing
  • Uses Conventional Props & Engine Bearers
  • 2 year International Warranty
  • Conventional Starting
  • Ideal for General, Scale and Fun-Fly

This new all die cast 4-stroke has been designed to meet the demand from aero modellers who want a quality engine at competitive prices. Its ultra low profile, good power and use of conventional size props makes it the ideal choice for all modellers.


RCV91-CD Specification:

The RCV 4-cycle engine has only one more moving component than a 2-cycle engine - the rotating cylinder itself. The cylinder is suspended between two bearings allowing it to rotate freely around the piston; the piston and crank are entirely conventional. A gear formed around the base of the cylinder meshes with a 2:1 reduction gear on the crank. As the piston reciprocates and the crank turns, the cylinder rotates around the piston at half engine speed. At the top end of the rotating cylinder there is a single port leading to the combustion chamber. This is surrounded by a fixed timing ring with three radially arranged ports; inlet, ignition and exhaust. This simple valve arrangement serves the combustion chamber as the engine cycles through the conventional 4-cycles: induction, compression, power and exhaust. Ignition is achieved through a standard 4-cycle glow plug exposed once only during each complete cycle. The rotating cylinder is effectively combined with the rotary valve in a single component hence RCV - rotating cylinder valve . A shaft attached to the cylinder rotates at half engine speed producing high torque and facilitating use of larger and quieter scale propellers.

Use of modern materials and the beneficial honing action between the piston and rotating cylinder minimizes any internal wear. Without the need for complex overhead poppet valves, the 4- cycle RCV engine design has proved to be inherently reliable.

Advantages of the RCV engine

The rotating cylinder is in-line with the axis of rotation of the propeller, producing an extremely streamlined shape and small footprint. The SP series fits within most small diameter cowlings.


Behind the Propeller Starting - The engine may be started from behind the propeller using a handheld electric starter inserted directly into a socket located on the end of the crankshaft. This enables the operator to remain safely behind the prop at all times.

              • 2:1 Output Gearing - Enabling the use of larger, quieter and more efficient scale propellers.
            • Radially Mounted - No need for nylon engine bearers. Easy and accurate thrust line adjustment.
            • Ease of Operation - are quality CNC machined and are easy to start and tune.
  • Low Maintenance - Few parts mean built in reliability. No complex valves and rockers to seize. Cleaning and re- assembly is straightforward.

International Guarantee - Manufactured to quality standard ISO 9000 all new engines are covered by a comprehensive 2 year international warranty. Lifetime after sales technical support is available Free to all our customers.

  • Choosing The Right Engine - RCV 4-cycle engines are direct equivalent of conventional 4-cycle engines. Just use the engine size as recommended by your model kit manufacturer. Customer Service - BlackFly Aero can assist with specific advice on applications.

2,3,4 Blade PROPS in stock for all engines.

Scale look, scale size! See APC Product Page

Canadian Sales are subject to 7% GST and Ontario residents 8%PST and shipping.

Ordering information

BlackFly Aero products can be ordered by sending an E-mail to us at or leaving a message at,

1-877-870-3552 or (705) 685-7614

and we'll respond ASAP. Shipping and taxes are extra. Insurance extra.


BlackFly Aero will accept returns on unused merchandise in original packaging and provide refund to the purchaser within 30 days of date of shipping, less costs of shipping and 10% restocking charge.

RCV warrant their product for two years from date of sale and will repair or replace the product at their discretion. Please submit warranty registration as soon as possible and contact RCV for warranty issues. BlackFly Aero stocks many parts for the RCV engine line and will provide support for installation and operation. Nothing herein is intended to supersede or contradict the manufacturers warranty.


BlackFly Aero has made every effort to ensure that the information contained herein is accurate and up-to-date, and can not be held liable for any errors or omissions. By their very nature, remote control model engines can be hazardous. Installation and construction techniques may vary making it impossible for us to control application of the product and thereby be responsible for damage or injury caused by its use. It is the responsibility of individuals to consider their own safety and neither BlackFly Aero or its employees can be held liable for any injury that may result from participation in this hobby.

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Does an RCV engine fit your plans or model?

Download full size front and side view drawings in Acrobat.pdf format:



See our RCV 90SP powered Skyraider in Skyraider Gallery.

See Wayne Haldenby's RCV powered Delta in customer gallery.


See a sample installation

More information? See FAQ and read the Model Airplane News review.

CD engines user manual

SP engines user manual

updated February 25, 2005