Go Back  RCU Forums > RC Airplanes > Questions and Answers
Reload this Page >

os .61 sf question

Questions and Answers If you have general RC questions or answers discuss it here.

os .61 sf question

Old 03-19-2003, 12:24 AM
Thread Starter
My Feedback: (4)
Join Date: Mar 2003
Location: Norwalk, CA
Posts: 49
Likes: 0
Received 0 Likes on 0 Posts
Default os .61 sf question

Does anyone out there know the difference between an o.s. fx engine and an o.s sf? and do you have any info on the o.s. .61 sf? I am looking for bph and max rpm and recomended prop. thanks.
Old 03-19-2003, 01:51 AM
My Feedback: (11)
FLYBOY's Avatar
Join Date: Jan 2002
Location: Missoula, MT
Posts: 9,037
Likes: 0
Received 2 Likes on 1 Post
Default os .61 sf question

I don't remember the BHP but I use an 11 X 7 on it. It doesn't have the power of an FX engine though. They have a bit more from what I remember.
Old 03-19-2003, 03:23 PM
Bob Yeager
My Feedback: (5)
Bob Yeager's Avatar
Join Date: Jan 2002
Location: Lake Havasu City, AZ
Posts: 521
Likes: 0
Received 0 Likes on 0 Posts
Default OS .61 SF

IMHO, this is the best engine ever made by OS.

Displacement 9.97cc (.6085 cu. in)
Bore 23.0mm (.9055 in.)
Stroke 24.0mm (.9449 in.)
Weight 535g (18.9oz.), 540g (19.0oz.) ABC
Practical R.P.M. 2,000-17,000
Power output 1.85 BHP/16,000 r.p.m.
Shaft thread UNF 5/16"-24
Suggested Propeller Sizes: 11x10-12x11 (pattern)
11x8, 12x7, 12-1/2x6, 11x7 (3-blade)
12x6 (3-blade) (sport)
Old 03-20-2003, 03:11 AM
Senior Member
Join Date: Mar 2002
Location: tucson, AZ
Posts: 482
Likes: 0
Received 0 Likes on 0 Posts
Default os .61 sf question

I'm a big fan of the old .61SF, too. It was a long-stroke motor while the new .61 FX is not. Also, the cylinder head is very different on the new motor compared to the SF's. I don't think any parts interchange between the two series.
Old 03-20-2003, 04:16 AM
Join Date: Dec 2001
Location: Las Cruces, NM
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Default os .61 sf question

My own experience is that the .61 SF is more powerful than the FX. It's also louder. Definitely one of my favorite engines.
Old 03-22-2003, 02:28 AM
Senior Member
Join Date: Sep 2002
Location: Garland, TX
Posts: 361
Likes: 0
Received 0 Likes on 0 Posts
Default os .61 sf question

well, im lookin at an add that says 17000, but Im sure youl have to use a 10 6 to get that, and that would be a waste of the longstroke. I use an 11/6 on my two. Ditto to the best engine os ever made! Too bad the ole man passed away, along with any reason to buy an O.S.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.