• J3-Cub.com is the largest community of J3-Cub pilots, owners and enthusiasts. With over 1000 active members, we have fostered a vibrant community and extensive knowledge base. J3-Cub.com hosts a library of over 13 years of technical discussions, J3 data, tutorials, plane builds, guides, technical manuals and more. J3-Cub.com also hosts an extensive library of J3-Cub photos.

    Access to the J3-Cub.com community is by subscription only. Membership is only $49.99/year or $6.99/month to gain access to this community and extensive unmatched library of knowledge.

    Click Here to Become a Subscribing Member

    You will also get two J3-Cub decals as well!

Redline for C85-12?

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Skybolt

Active Member
Supporting Member
Joined
Apr 30, 2020
Messages
31
Reaction score
12
Hello
I am trying to determine the actual redline rpm of the Continental 85-12 in the J3 I now own. I searched for redline on this forum and found information that suggests it may be above 2500rpm, but the conversations were muddled with 0-200 crankshafts.
Looking at the TCDS for C-85-12 I see:
Max. continuous hp., r.p.m., full throttle at sea level pressure altitude 85-2575
Takeoff hp., 5 min., r.p.m. full throttle at sea level pressure altitude 85-2575 (87-2650 for -J, -FHJ and -FJ models only)
I am a little confused by this wording. Max continuous rpm sounds like it can be run forever at that rpm, yet directly below it states 5 minutes max. Which is it? Is 2575 what should be on the tach for a redline? The reason I ask is that someone put a redline of 2450 on the tach on my new to me cub, and I have been observing it until I could determine more. Looks like it is incorrect.
If 2575 is correct for redline, what is a good number for the top of the green arc, assuming such a thing exists for this engine?
 
Last edited:

Latest posts

Back
Top