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O.S. 70 FS (I)

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Old 11-25-2002, 07:16 AM
  #1
Pepe J
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Default O.S. 70 FS (I)

APC 13 X 6 + 15% Nitro. + OS "F" Plug, 100' alt. = 10,500 RPM
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Old 02-14-2003, 11:35 PM
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Default O.S. 70 FS (I)

My O.S. 70 is pretty new, only 3 tanks run thru it. Turns 10,200 on a 13-6 Master Airscrew.
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Old 02-28-2003, 01:24 PM
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Default Re: O.S. 70 FS (I)

Same here, 10800 peaked 10400-10500 ready to fly

Quote:
Originally posted by Pepe J
APC 13 X 6 + 15% Nitro. + OS "F" Plug, 100' alt. = 10,500 RPM
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Old 03-04-2003, 03:33 AM
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Default O.S. 70 FS (I)

10.8K on an APC 13x6, 15% Power Master Fuel
11.25K on APC 12.25x3.75, 15% Power Master
both with OS-F plugs
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Old 03-14-2003, 07:15 AM
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Pepe J
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Default O.S. 70 FS (I)

I just recently switched to a fully synthetic fuel. 15% Nitro-18% oil which I added 3oz of castor for a 20% oil content. I gained an additional 300 RPM, but the TORQUE...... Big time torque improvement. I can't wait to try this fuel in my other 4 strokes!

Happy Fly'n....
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Old 04-25-2003, 11:20 AM
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Default 70 II Four Stroke

I am getting a 9500 to 10000 RPM with a 12X6 prop, 80-20 Fuel is that alright.

Sharad
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Old 04-25-2003, 12:38 PM
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Steve Guinn
 
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Default O.S. 70 FS (I)

That is right where you want to be. Bax says they like to run them in the mid 9's for a smooth transition.
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Old 10-12-2005, 06:55 AM
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Default RE: O.S. 70 FS (I)

My very well used FS70 Surpass (10 Gall.+) turns with Coolpower 10%:

13x4W APC 11000

13x6 APC 10500 (private "blended" mix: 5% nitro, 11% castor, 5% molsyn 150)
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Old 02-12-2009, 02:48 PM
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Default RE: O.S. 70 FS (I)

15% coolpower with added castor 12x7 apc and OS F glowplug 10,800 peak and 10400 to fly, i cat wait to try it out...... i got this engine "frozen" and dissassembled it a few months ago. it, set the valve lash, and finally got around to putting her in a plane.
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Old 02-13-2009, 04:13 PM
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Default RE: 70 II Four Stroke


Quote:
ORIGINAL: Toucan

I am getting a 9500 to 10000 RPM with a 12X6 prop, 80-20 Fuel is that alright.

Sharad
I think you should get those numbers with a 13x6 prop.
A 12x6 prop is a little small for this engine.
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Old 02-14-2009, 01:22 AM
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Default RE: 70 II Four Stroke

you are right, but he isnt using any nitro in his fuel....according t0 him, its 80%methanol and 20 %lube
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Old 02-28-2009, 05:37 PM
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Default RE: O.S. 70 FS (I)

good catch Metallica
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Old 03-09-2009, 08:48 PM
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Default RE: O.S. 70 FS (I)

I'm getting 9300 with 15% Coolpower on a 14x4W APC. That seems low to me. Someone else reported getting 10,000 on that prop. The engine has had a fair amount of use, but has been well cared for. Bearings are smooth, compression seems fine.

I adjusted the valves and noticed that when I press them down, they come up a little bit slowly. Not very slowly, but they don't pop right back up. Is that a sign that they've gotten gummed up (it has had fuel with castor in the past)? Could I get some power back by disassembling and cleaning?

Jim
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Old 03-09-2009, 10:52 PM
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Default RE: O.S. 70 FS (I)

i would have to say yes
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Old 04-03-2009, 03:18 PM
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Default RE: O.S. 70 FS (I)

I don't think I would disassemble it.
I would take the back plate, cam cover, and valve cover off.
Remove the glow plug.
Rotate the crank so the piston is down.
Throw it in a crock pot and cover with antifreeze until 1 or 2 inches submerged.
Put the lid on the crock pot and set the heat to low and let it cook overnight.
It should come out looking almost brand new.
Dry it (blow it out with air hose if available) and apply liberal dose of WD40 through out the engine.
Dry it (blow it) again, apply liberal dose of light weight oil (air tool oil, after run oil, marvel mystery oil).
Put the covers back on and see how it runs.
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Old 04-06-2010, 04:33 PM
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Default RE: O.S. 70 FS (I)

OS70 Supass new bearings 15% nitro apc 14x4w prop 10,050 tuned to fly

Edit* Surpass I
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Old 04-14-2010, 12:27 PM
  #17
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Default RE: O.S. 70 FS (I)

OS 70 II Surpass

APC 13x7 with 15% omega fuel 9,800 rpm

Sea level
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