VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Model Specific > RV-6/6A
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 07-07-2018, 04:02 PM
MountainU2 MountainU2 is offline
 
Join Date: Aug 2017
Location: Roseville, CA
Posts: 16
Default Can of Worms: O-360 CS Hartzell Setting Advice

Okay, so as the title suggests, I know I am opening a can of worms here. But single engine piston—and especially constant speed propeller stuff—is new to me, and if I’m being brutally honest with myself it’s a little bit mystifying.

I have flown jet aircraft for years, and between the Airbus I currently fly, and the U-2 which I flew in the Air Force, I feel pretty stoopid when I have to actually think about what my engine’s doing. Heck, in the U-2 (yes, they’re still flying), you push the throttle to “mil” on takeoff and usually leave it there until descent. Now I have not one, but TWO more levers to think about.

I bought my first plane, an RV-6 with the above eng/prop setup a few months ago. I understand the basics, and have flown my plane a lot using a formulaic approach to settings, but I need more info. I shoot for <= 380 CHT, and my usual flying is at 6500 or 7500ft in the SF Bay area. I find my MP at cruise and full throttle is 22-2300, and I set the prop at 2300. Then I lean until peak, keep going until slightly rough, then back in a couple turns. I end up with about a 1250 EGT. Seems like about 130-140 kts IAS is where she’s happy.

Am I in the right ballpark? I’m not worried about how fast I can go; I want to keep my engine happy and dependable for as long as possible. I looked for threads here, and surprisingly didn’t see much. Also googled the **** out of this, and found some great advice for fuel injected 540s. Again, not much for our setup.

Fire away.
__________________
Keith
RV-6 N91CN
KLHM, CA
Dues Paid

Last edited by MountainU2 : 07-07-2018 at 04:06 PM.
Reply With Quote
  #2  
Old 07-07-2018, 04:29 PM
chrispratt's Avatar
chrispratt chrispratt is offline
Super Moderator
 
Join Date: Oct 2005
Posts: 647
Default

Keith:

Welcome to the world of small aircraft.

For what's it's worth (since I fly an -8) but have the O-360 with Hartzell C/S here are my typical settings:

MP: 24 inches (or full throttle at higher altitude)
RPM: 2350
Lean: Highest EGT - less than 1400 (usually about 1380); CHT - highest is usually less than 340 (I believe 400 is the max that Lycoming recommends); oil temp is usually just below 180 (carburetor engine, results vary with the seasons.)

Leaning the way you described is fine. It always worked for me before I had instruments to tell me things like EGT and CHT. I don't have a fuel computer - if I did I would probably lean it a bit more but the readings above will keep your engine in good condition. Mine has run like a top (knock on wood) for 750 hours.

Chris
__________________
Chris Pratt (2018 VAF DUES PAID)
RV-8 Flying, 750+ hours
N898DK
Lycoming O-360-A1A, Hartzell CS
52F (Aero Valley Airport, TX)

Last edited by chrispratt : 07-07-2018 at 04:32 PM. Reason: clarification
Reply With Quote
  #3  
Old 07-07-2018, 04:34 PM
MountainU2 MountainU2 is offline
 
Join Date: Aug 2017
Location: Roseville, CA
Posts: 16
Default

Thanks! So at higher altitude, what is your MP? Is my ~2200 at 7500 ft about right?
__________________
Keith
RV-6 N91CN
KLHM, CA
Dues Paid
Reply With Quote
  #4  
Old 07-07-2018, 04:40 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,125
Default 0 360

Avoid continuous operation between 2000.2250 r/m. The tachometer should have a yellow arc in that range, most probably do not.Try running the rpm at 2350 or 2400, it should be noticeably smoother at that r/m.
The EGT reading is irrevalent. What you are seeking is a reading below peak EGT. Lean to peak then richen 50-100 degrees.
If your CHT's are under 400, at 7500' or higher it is almost impossible to hurt a normally aspirated Lycoming with the mixture control. It may or may not be possible to run lean of peak with a carburetor.
Reply With Quote
  #5  
Old 07-07-2018, 04:40 PM
chrispratt's Avatar
chrispratt chrispratt is offline
Super Moderator
 
Join Date: Oct 2005
Posts: 647
Default

Quote:
Originally Posted by MountainU2 View Post
Thanks! So at higher altitude, what is your MP? Is my ~2200 at 7500 ft about right?
22 inches is about right. On longer trips, I like to fly at 7500-8500 feet and full throttle because that's where the O-360 is most efficient. So you're at full throttle there. At those altitudes, my MP will read somewhere between 21 and 22 inches.

The IO-360 guys get a little more MP there but not much.

I'm jealous of your U2 flying. It must have been a thrill. You'll have to get used to a different vantage point now, and look out for more traffic.

Chris
__________________
Chris Pratt (2018 VAF DUES PAID)
RV-8 Flying, 750+ hours
N898DK
Lycoming O-360-A1A, Hartzell CS
52F (Aero Valley Airport, TX)
Reply With Quote
  #6  
Old 07-07-2018, 04:42 PM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 419
Default

Iím envious of your flying experience!
Your prop/power/mixture procedure works fine. A couple notes I can think of;
Depending on which prop model you have, Check with your propís mfgr to see if there are any limitations for operating at certain RPMs continuously, and engines with carbs donít benefit much when leaned too much past peak.
__________________
Ralph
Maintain lots, upgraded & repaired some, modified more, rebuild a few, & built 4 of 'em
Reply With Quote
  #7  
Old 07-07-2018, 04:50 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 5,352
Default

Quote:
Originally Posted by MountainU2 View Post
Thanks! So at higher altitude, what is your MP? Is my ~2200 at 7500 ft about right?
Yes. At full throttle, you should see the actual atmospheric pressure outside the plane, minus any losses going thru the air filter and induction system, plus any gain due to ram air pressure. A rough rule of thumb is 30Ē at sea level, minus 1Ē per thousand feet altitude. So for you 30 - 7.5 = 22.5Ē, about right. I assume you meant 22Ē, not 2200.
Reply With Quote
  #8  
Old 07-07-2018, 04:50 PM
MountainU2 MountainU2 is offline
 
Join Date: Aug 2017
Location: Roseville, CA
Posts: 16
Default

Great. Ideally I take off at full throttle (of course) and just leave it there until descent, assuming a cruise alt over 5000ft. Itís those other two squirrelly knobs that are so mysterious.

So do you lean in the climb? How about the prop? Say youíre climbing to 7500ft... When do the blue and red thingys become active? In what order? I feel like I know what to do when I get to cruise altitude (mostly), but how about on the way to it? Is this a lot of questions? If I have to ask, donít I already know?!
__________________
Keith
RV-6 N91CN
KLHM, CA
Dues Paid
Reply With Quote
  #9  
Old 07-07-2018, 04:51 PM
MountainU2 MountainU2 is offline
 
Join Date: Aug 2017
Location: Roseville, CA
Posts: 16
Default

Quote:
Originally Posted by BobTurner View Post
Yes. At full throttle, you should see the actual atmospheric pressure outside the plane, minus any losses going thru the air filter and induction system, plus any gain due to ram air pressure. A rough rule of thumb is 30” at sea level, minus 1” per thousand feet altitude. So for you 30 - 7.5 = 22.5”, about right. I assume you meant 22”, not 2200.
Yes. Thanks! Man, that helps a lot.

Oh, and yeah, 22” Hg. See why I need help?
__________________
Keith
RV-6 N91CN
KLHM, CA
Dues Paid

Last edited by MountainU2 : 07-07-2018 at 04:58 PM.
Reply With Quote
  #10  
Old 07-07-2018, 05:06 PM
flyinga flyinga is offline
 
Join Date: Dec 2007
Location: Fredericksburg, TX
Posts: 526
Default

Keith,

Yes...lean in climb. You said you have about 1250 EGT on takeoff; lean during climb to that EGT.
__________________
Jim Averett
RV-8
TS36 - Silver Wings
Fredericksburg, TX
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 11:35 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.