Buy a new O.S. engine between August 3, 2009 & December 31, 2009 and trade in an old engine, you'll receive up to $150 in Bonus Bucks as a reward. They come in the form of a merchandise certificate which you can use to buy products from many of R/C's most respected manufacturers.

For each O.S. engine purchased, provide the items below and mail to: O.S. Bonus Bucks, 1608 Interstate Dr., Champaign, IL 61826.

• A completed request form, Download the Form Here
• A dated retailer sales receipt
• A proof-of-purchase from your new engine
• Your trade-in engine

For Bonus Bucks Reward Amounts & Complete Rules Visit the Official OS Bonus Bucks Website

Helicopter Engines

.50 SX-H Ringed Hyper

Part No.	PHOTO	Description	CART	Price
OS MG1951		Engine .50, SX-H Hyper Ringed Heli, O.S. Engines In Stock!

A "Hyper" engine for superior heli performance!

For over-the-top flying excitement, the .50 SZ-H Ringed Hyper engine is the clear favorite.

• The Hyper version weighs less than the .50 SX-H, but delivers more horsepower for higher rotor speeds.
• Actually mounts in the same space as a .30-size application.
• The 60LH carburetor features 1.5mm more bore, to increase overall power.

Part No. OS MG1951 Displacement: 0.499 cu in (8.17cc) Bore: 0.866 in (22mm) Stroke: 0.847 in (21.5mm) RPM: 2,000-20,000 Output: 1.9 hp @ 17,000 rpm Weight: 14.3 oz (406g) Includes: 60LH carburetor, #8 glow plug Requires: muffler, drive hub

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.70 SZ-H Ring 3D

Part No.	PHOTO	Description	CART	Price
OS MG1972		Engine .70, SZ-H Heli, O.S. Engines In Stock!

Increase power – with drop-in ease!

You want MORE POWER to give your .60-size helicopter more authority in challenging maneuvers. You don't want to take on time-consuming mounting modifications and gearing changes.

O.S. has the answer: the .70 SZ-H. It installs in the same space as a .61, and operates in virtually the same rpm band...so you can upgrade in an instant, and right away enjoy extra muscle for 3D flying and FAI F3C competition.

• Specifically developed to satisfy the performance demands of FAI F3C competition pilots.
• Throttle assembly reference marks make it easy to note and restore finely tuned settings after maintenance.
• Additional mounting lug on front of crankcase increases stability during extreme maneuvers.
• Front and rear ball bearing supported crankshaft reduces friction and wear.
• Three-needle carburetor permits exceptionally precise adjustments.
• Large helicopter cylinder head offers generous cooling fin area–increased webbing on the crankcase front improves heat dissipation even further.
• The .70 SZ-H Ringed engine's carburetor includes a mid-range needle that enables pilots to achieve extremely precise adjustments.
• A push/pull throttle arm offers added finesse and precision in power control.
• Additional lugs are provided on the crankcase for increasing stability in models with mounts able to take advantage of them.

Part No. OS MG1972 Displacement: 0.702 cu in (11.5cc) Bore: 1.016 in (25.8mm) Stroke: 0.866 in (22.0mm) RPM: 2,000-18,000 Output: 2.5 hp @ 16,000 rpm Weight: 19.5 oz (553.5g) Requires: muffler & fuel

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