OS FS-70 Venting - What's correct way?
 

Just picked up an OS FS-70 from another RC Universe member today. I already had a Surpass II 70 on another plane and was used to its plumbing. All I have done with the Surpass II 70 is hook fuel line from carb to tank and go fly. No need for tank to be pressurized. Now with this OS FS-70, it has two nipples on the exhaust pipe and another nipple on the plastic cover on the back of the crankcase. Can I just block all three nipples up and go fly or do I need to vent the crankcase? Sounds like a dumb question but nowhere in instruction manual from OS does it talk anything about this subject. Thanks

RE: OS FS-70 Venting - What's correct way?
 

It sounds like the previous owner modified it for smoke. A picture would be helpful in helping you understand what you have.

On a side note, are you sure you bought an FS-70? I'm thinking the FS series all had metal backplates, unless it was damaged in a crash and replaced with a plastic one. Is it maybe the FL-70 you have aquired?

RE: OS FS-70 Venting - What's correct way?
 

Sounds like an FL .70. The 2 nipples on the silencer have different size holes. The nipple with the larger hole goes to the tank. The one with the smaller hole hooks to the nipple on the backplate. You can get a copy of the manual here: http://manuals.hobbico.com/osm/fl-70-manual.pdf
You will have to pressurize the tank with the FL. It's an ABC engine meaning that the cylinder is tapered, and doesn't have a ring like the surpass. Therefore, it won't have the draw that the surpass has.

RE: OS FS-70 Venting - What's correct way?
 

Look at pages 18-20 in the link broke_n_bummin provided.

RE: OS FS-70 Venting - What's correct way?
 

That's exactly what I was looking for! Thanks for your help.