REFLECTOR: Running LOP -- Climbing or Cruising

[Bob Jackson (Jax Tech)]

Thanks Scott & Brett,

 

I think Brett answered the question, and the answer is there is nothing
wrong with running LOP at any altitude, provided you're not at too high of a
power setting (generally accepted in the Tornado Alley (Turbo Cirrus)
community as 75 to 85% power.  So if you want to climb WOT (and you're not
turbocharged) once you get above 5-6000' there is only enough air to get
75-85% power, so you may as well be LOP (assuming you can still keep your
CHTs down).

 

But that doesn't mean that you can't run LOP at any altitude, as long as
you're below 75-85% power where detonation shouldn't be a problem -- which
was my question.  I think Brett's answer (which applies only to full power
ops) has been turned around inadvertently by some to mean you can't run LOP
safely below 5-6000', which I don't believe is the case, provided (as in all
LOP operations) that you're not at a power setting above 75-85% (and you're
temps are OK) in order to minimize the detonation risk.

 

We've studied the Deakin/Tornado Alley articles a lot over the years because
that's how we want to operate.  I think these guys have re-opened a whole
new dimension to efficient, safe and good-for-your-engine operations for
general aviation.  The Turbo Cirrus, for one, is designed around LOP
operation.  I was just wondering whether there was something we had missed
concerning cruising LOP at low altitudes...

 

Thanks,

Bob

 

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Scott Derrick
Sent: Thursday, November 11, 2010 9:59 AM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: Running LOP in the climb

 

Here's a link to JOhn's article with instructions on how to run LOP in teh
climb to altitude.

http://www.avweb.com/news/pelican/182085-1.html

Scott

-------- Original Message --------
Subject: Re: REFLECTOR: Auto engine installed 172
From: Brett Ferrell  <mailto:reflector at velocityxl.com>
<reflector at velocityxl.com>
To: reflector  <mailto:reflector at tvbf.org> <reflector at tvbf.org>
Date: 11/11/2010 06:49 AM



Bob,

 

I'm not an expert, so I'll probalby get part of it wrong, but as I
understand it:

*	Running LOP at "Full Power" risks detonation
*	"Full Power" is only possible below something like 5-6,000', above
that the air is so thin, you cannot generate over 75% power
*	Thus leaning above that altitude is safe, because you can't generate
enough power to risk detonation.

But here is an article that is probably much, much more useful.

http://www.avweb.com/news/pelican/182132-1.html


Brett

 
 

 

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Bob Jackson
Sent: Wednesday, November 10, 2010 10:36 PM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Auto engine installed 172

 

You're right, Scott and Sid!

 

I said "electronic ignition" -- I meant "electronic fuel injection".  With
Gami injectors and the already-well-balanced airflow of the IO-550N, LOP is
a piece of cake and the standard operating mode for us in cruise at any
altitude.  What we need is better fuel injection.  I'm hoping Sid will have
an availability list for that, too!

 

A while back there was some talk of it being bad or dangerous to run LOP at
low altitudes, but I never heard anyone explain their "why".  Other than
wanting to be back set up ROP in the pattern for any required WOT go-around,
can someone explain to me the above concern?  We routinely cruise LOP at all
altitudes without distinction.

 

Thanks,

Bob

 
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