The UMS 7-Cylinder 90cc Petrol Radial Engine delivers authentic seven-cylinder radial realism in a compact and lightweight 4-stroke package. Designed for smaller scale aircraft and warbirds, it combines smooth power delivery, CNC precision engineering, and long-term durability.

Product Description

The UMS 7-90cc Radial Engine is a compact, high-quality 4-stroke petrol engine built for scale aircraft enthusiasts who demand authentic appearance and dependable performance. Its classic 7-cylinder radial configuration provides the unmistakable look and sound of full-size aviation engines, making it ideal for detailed warbirds, vintage aircraft, and museum-quality scale projects.

With a 90cc displacement, this engine offers strong, balanced power for smaller and mid-size scale aircraft while maintaining a lightweight design for optimal flight characteristics.

Supplied ready to run, the engine includes:

• Exhaust collector ring

• Electronic ignition system

• Spark plugs

• Durable engine mount

Integrated choke and throttle bellcranks simplify installation and ensure smooth throttle response, making setup straightforward for both experienced builders and advanced hobbyists.

Manufactured using CNC-machined aluminium and bar stock components, the engine delivers precision tolerances and consistent performance. The aircraft-grade alloy cylinder heads and crankcases provide excellent strength-to-weight balance, helping maintain correct centre of gravity in scale builds.

Internally, durability is prioritised through:

• Heavy-duty double-bearing crankshaft for stable high-RPM operation

• Billet aluminium pistons with hardened steel rings

• Hard-chromed and lapped cylinder bores for reduced wear

• Hardened steel camshafts for reliable valve timing

Designed to run on 87–110 octane petrol with a 32:1 fuel-to-oil mixture, the UMS 7-90cc offers reliable starting, smooth throttle transition, and long service life.

Whether powering a scale warbird or a detailed classic aircraft, this engine delivers the perfect balance of realism, performance, and engineering quality.

Key Features

• 7-cylinder 4-stroke petrol radial engine

• 90cc displacement – ideal for smaller scale aircraft

• Authentic radial sound and appearance

• Ready-to-run package with ignition and collector ring

• CNC-machined aluminium and bar stock construction

• Aircraft-grade alloy cylinder heads and crankcases

• Double-bearing crankshaft for durability

• Billet pistons with hardened steel rings

• Hard-chromed, lapped cylinder bores

• Compatible with 87–110 octane petrol (32:1 mix)

Perfect For

• Smaller scale RC warbirds

• Vintage and golden-era aircraft replicas

• Builders seeking compact 7-cylinder realism

• Scale competition models

• Advanced hobbyists and professional builders

Specifications

Engine Type: 4-Stroke
Cylinders: 7 (ABC Type)
Displacement: 90cc
Bore: 25.1mm
Stroke: 26.0mm
Approx. Thrust: 9.5kgf @ 24×10 prop
RPM Range: 1,000 – 5,500
Weight (with silencer & ignition): Approx. 3.5kg
Engine Diameter: 230mm
Engine Length: 170mm
Recommended Propellers:

• 2-Blade 26×10

• 2-Blade 24×12
  

Muffler Type: Collector Ring
Spark Plug: 1/4-32
Carburettor: Walbro
Fuel Type: Petrol (87–110 octane, 32:1 mix)

Why Buy from Probuild Aircraft

✅ Official UK stockist – 100% genuine UMS engines
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✅ Fast UK shipping and secure packaging
✅ Supplying and supporting pilots since 1993

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