Technical note
Twin-Cylinder Steam Engines: Torque Delivery, Phasing and Balance
Why two cylinders improve starting opportunities and torque continuity, and what that means for a small live-steam plant.
Read engineering note ↗RW-V2 · Compact 90° twin-cylinder steam engine
V2 Twin-Cylinder Model Steam Engine
Double-cylinder character in an exceptionally compact footprint.
Discuss this model
The V2 at a glance
An official Rocking Whale product.
The RW-V2 is a compact 90° twin-cylinder model steam engine for working model boats and miniature engineering projects, with guidance for 70–130 cm boats.
The RW-V2 places two cylinders at 90 degrees to bring smooth, stable twin-cylinder running to a compact model steam engine. It is designed for builders who want substantial mechanical presence without giving up space.
The compact V2 gives retailers a twin-cylinder option for builders working with limited installation space while retaining a clearly visible mechanical layout.
- Die-cast brass main structure
- Brass cylinders with stainless steel liners
- Ball-bearing supported crankshaft
- Complete Stephenson valve gear for forward and reverse
On-water demonstration
Rocking Whale RW-V2 Model Steam Launch Demonstration
Watch the Rocking Whale RW-V2 twin-cylinder steam engine powering a radio-controlled model steam launch on open water.
Reference data
Technical specifications.
Figures are provided as a selection guide. Specifications are subject to alteration for improvement without notice.
- Configuration
- 90° twin-cylinder
- Displacement
- 6 cc (1.5 cc × 2 × 2)
- Bore × stroke
- 12.2 mm × 12.7 mm
- Speed
- 3000 RPM
- Max. torque
- 1200 gf·cm
- Power
- 0.03 HP
- Engine weight
- 600 g
- Recommended boat size
- 70–130 cm
- Normal working pressure
- 0.5–2 bar
- Maximum working pressure
- 3 bar
- Product size
- 120 × 81.5 × 106 mm
- Package size
- 180 × 140 × 100 mm
- Packed weight
- 750 g
The V2 in detail
A closer look at the mechanism.
Product, detail, installation and running photographs from the Rocking Whale workshop.
Engineering background
Read the technical notes.
In-depth engineering analysis, historical context, and mechanical principles for the RW-V2.
Technical note
90° Twin-Cylinder Steam Engines: Compact Geometry and Phasing
How a 90-degree cylinder-bank layout packages a twin compactly, while separately selected crank and valve phase determine torque overlap.
Read engineering note ↗Technical note
How to Assemble & Time Stephenson Valve Gear
A practical engineering guide to the layout, eccentric offset setting, link geometry, and lead timing of Stephenson reversing valve gear on live-steam models.
Read engineering note ↗Commercial resources
Evaluate the details.
Use the current manuals and specifications to review the model. Product materials and commercial information are available through a direct enquiry.
Trade & volume enquiries
Discuss the V2.
For distributor evaluation, sample requirements or volume quotations, tell us about your company, market and expected quantity. Contact Rocking Whale for current product price and shipping information for your project.
[email protected] ↗Selection guidance
Frequently asked questions.
What model boat size is recommended for the V2?
The V2 is recommended as a selection guide for model boats approximately 70–130 cm long.
Does the V2 have reversible valve gear?
Yes. The V2 has complete Stephenson valve gear for forward and reverse running.
What is the V2 price?
Contact Rocking Whale for the current product price and shipping information. Include your project, quantity and destination so we can prepare an appropriate quotation.
What does RW-V2 mean?
RW-V2 is the Rocking Whale model designation for this twin-cylinder model steam engine.
How does Stephenson valve gear enable forward and reverse running on the RW-V2 in RC model boats?
The RW-V2 utilizes dual eccentric sheaves per cylinder connected to a curved expansion link (Stephenson link motion). Shifting the reversing lever changes valve lead and steam admission order, reversing shaft rotation directly without requiring a mechanical gearbox.
Can the RW-V2 90° twin-cylinder steam engine run on compressed air?
Yes. The RW-V2 operates efficiently on 0.5–2 bar (7–30 psi) compressed air for bench demonstrations, air testing, and timing checks, providing smooth, quiet mechanical rotation up to 3000 RPM.