OS Speed R21GT II Combo Set

The OS Engines OS Speed R21GT II Combo Set delivers the next evolution of the acclaimed O.S. SPEED R21GT GT nitro engine. Inheriting the smooth throttle feel and strong fuel efficiency of the previous model, this updated II version sharpens mid and low speed response for GT applications. Supplied as part no. SCH-OS1DT01, the combo includes the TB01 (EFRA2042) tuned silencer and MB01-70 manifold.

Engineering updates focus on power delivery and drivability. A revised crankshaft counterbalance improves torque in the medium and low ranges, while a newly designed inner head enhances idling performance. An inner head O-ring reduces vibration and improves dust resistance, and a lighter outer head further refines handling characteristics.

Key Features

• Enhanced mid and low speed power via revised crankshaft counterbalance
• Retains the smooth feel and good fuel economy of the previous R21GT
• New inner head design for improved idle stability
• Inner head O-ring reduces vibration and boosts dust resistance
• Lighter outer head for more responsive handling
• Combo set with TB01 (EFRA2042) tuned silencer and MB01-70 manifold

Combo Contents

• O.S. SPEED R21GT II engine
• TB01 tuned silencer (EFRA2042)
• MB01-70 manifold

Specifications

• Displacement: 3.49 cc / 0.213 cu.in.
• Bore: 16.08 mm / 0.633 in.
• Stroke: 17.20 mm / 0.677 in.
• Output: 2.65 ps / 2.61 hp / 34,000 r.p.m.
• Practical r.p.m. range: 4,000–42,000 r.p.m.
• Weight: 362 g / 12.77 oz

Standard Accessories

• Glow Plug RP7
• Venturi 7.0 mm (RED) AL2
• Exhaust seal ring
• Dust cap set (φ3, φ16, φ18)