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HomeAircraftHelicopterEngines Plugs Mufflers Fuel › OS 50 vs OS 55 hyper
08-11-2010 02:53 PM  8 years agoPost 1
Scott1115

rrElite Veteran

Greenwich, CT

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Beside the obvious .05 displacement and .3 hp difference what is the difference. The block is the same. What has OS done to create the additional .05 displacement and hp?

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08-11-2010 04:04 PM  8 years agoPost 2
BarracudaHockey

rrMaster

Jacksonville FL

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The head and carb, the carb is the most significant change.

Edit: Nevermind, I thought it was OS50 vs 50 hyper. I'll go back to my corner now

Andy
AMA 77227
http://www.jaxrc.com

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08-11-2010 04:21 PM  8 years agoPost 3
Heli 770

rrProfessor

USA.

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OS. 50 OS. 55
Bore: 21.99mm. 23mm.
Stroke: 21.51mm. 23.5mm.

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08-11-2010 04:26 PM  8 years agoPost 4
Darren Lee

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Woodstock, GA

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08-11-2010 05:10 PM  8 years agoPost 5
Husker

rrApprentice

lincoln, ne

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Entirely different motors.

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08-14-2010 02:11 AM  8 years agoPost 6
specialtydevice

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New Rochelle , ny- USA

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not entirely different motors. Same block. The bore and piston is a hare bigger on the 55. Guys who fly the OS 55 have remarked they dont notice a difference in power from the OS hyper 50. Both motors still come with the horrible bearings that go out. The 55 has a 3 needle carb instead of a 2 needle on the 50 but not worth the $100 difference. The porting on the sleeve is the same. They still use muffler pressure. Muffler pressure = inconsistant fuel management as opposed to YS's crankcase pressure system delivering consistant fuel therefore having seemingly more power. OS has copied YS's crankcase pressure in the new 91 and the 55 will follow.

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08-14-2010 02:13 AM  8 years agoPost 7
specialtydevice

rrVeteran

New Rochelle , ny- USA

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the difference in the crankcases are more cooling fins on the 55 and a slightly larger bore for the sleeve.

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08-15-2010 03:18 AM  8 years agoPost 8
Gearhead

rrMaster

Vt

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as I remember the 55 has Porting Holes in the Piston..

Jim
Buzz Buzz Buzz

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