Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Fwd: plenum

Matronics Email Lists Forum Index -> RV8-List

View previous topic :: View next topic

Author Message

PeterHunt1(at)aol.com
Guest

Posted: Sat Jan 28, 2006 10:30 am Post subject: Fwd: plenum

Return-path: <PeterHunt1(at)aol.com>

From: PeterHunt1(at)aol.com

Full-name: PeterHunt1

Message-ID: <24c.5f1d665.310d0ff1(at)aol.com>

Date: Sat, 28 Jan 2006 13:20:33 EST

Subject: plenum

To: aflyer(at)lazy8.net

-------------------------------1138472433

John,

I too have built a nice aluminum plenum for my RV-6 (O-360-A1A).  Just  got 

it in the air, but immediately found hot CHT's on climb out.  I too  suspect my 

LASAR and am running tests to determine how much CHT drop there is  when I 

switch it off.  You said your Lightspeed system solved the problem,  but was 

there also any change in fuel burn?

Pete

-------------------------------1138472433

<META content=3D"MSHTML 6.00.2800.1264" name=3DGENERATOR>

<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20Arial"

bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drole_document

face=3DArial color=3D#000000 size=3D2>

John,

I too have built a nice aluminum plenum for my RV-6 (O-360-A1A).=20Just

got it in the air, but immediately found hot CHT's on climb out. I too

suspect my LASAR and am running tests to determine how much CHT drop there is

when I switch it off. You said your Lightspeed system solved the problem,

but was there also any change in fuel burn?

Pete

-------------------------------1138472433--

- The Matronics RV8-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV8-List

Nuisance

Joined: 10 Jan 2006
Posts: 9

Posted: Sat Jan 28, 2006 2:34 pm Post subject: Re: Fwd: plenum

Pete



I did not see a change in fuel burn, or in true airspeed when I switched. 



I only saw the reduction in CHT, and the increase in EGT, both about the same as when I turned my LASAR off.



I have the optional timing display with the Lightspeed...at 8500 ft, wide open throttle (23" map), and 2500 rpm, it only shows about 4 degrees advance from baseline. 



I don't know what the LASAR system was doing, they consider that information to be proprietary.



John

- The Matronics RV8-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV8-List

_________________
Life is too short to run lean of peak.

walter(at)tondu.com
Guest

Posted: Sat Jan 28, 2006 5:29 pm Post subject: Fwd: plenum

On 01/28  2:34, Nuisance wrote:



 > I don't know what the LASAR system was doing, they consider that 

 > information to be proprietary.



They must have told avweb, and I've also gotten this information

directly from them over the phone.  Here's a quote from avweb.



"With settings available from zero to 42 degrees before Top Dead Center, 

however, the LASAR matches the spark advance to make possible the most 

"fire in the hole" from the smallest possible amount of fuel."



And the whole article...



http://www.avweb.com/news/reviews/182489-1.html



-- 

Walter Tondu

http://www.rv7-a.com

Flying!

- The Matronics RV8-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV8-List

Nuisance

Joined: 10 Jan 2006
Posts: 9

Posted: Sun Jan 29, 2006 6:32 am Post subject: Re: Fwd: plenum

[quote="walter(at)tondu.com"]On 01/28  2:34, Nuisance wrote:

 > I don't know what the LASAR system was doing, they consider that 

 > information to be proprietary.

They must have told avweb, and I've also gotten this information

directly from them over the phone.  Here's a quote from avweb.

"With settings available from zero to 42 degrees before Top Dead Center, 

however, the LASAR matches the spark advance to make possible the most 

"fire in the hole" from the smallest possible amount of fuel."

Hi Walter

I did read that article back in '01, and that, together with a strong recommendation from Ken Tunnel at Lycon, is why I ordered my engine with the LASAR system.

The information I tried to get from Harry Fenton when he was still working for Unison was basically a timing map. That is, at what MAP and RPM does the advance start, and what is it at a normal cruise setting, and what is it at a high altitude cruise, etc. This information has always been withheld. We are given the range 0-42 degrees...I think Lightspeed says 0-40. But, it is the essence of this dicussion to consider when, and how much, advance is provided at various settings. This is what I am referring to when I say that the LASAR advance curve is too aggressive...too much advance comes in too early as MAP is reduced, and that is what causes the CHTs to run higher than they should. 

I firmly believe that with LASAR, by the time you provide enough extra cooling air to keep your engine at normal, sub 400 degree CHTs, you have caused enough extra drag to negate the benefit of any extra power you may be getting from the timing advance. You are also putting more strain on the rod and main bearings (see the discussion of thetaPP on the GAMI website, and John Deacon's articles on AVWEB).

I have read (somewhere, maybe on one of these email lists) that the E-mag people are using a more conservative timing advance curve, and I would leap to the conclusion that they are aware of these problems.

LASAR, as a certified system, is stuck with what they have. The company won't put more R&D into the system due to the poor market acceptance on the existing system...they won't even develop a system for Continentals. They did their testing on C-172s and various Pipers that provide huge masses of air for cooling (and go slow). They pushed the timing curve in the attempt to provide more attractive performance results, and didn't realize what would happen to the tighter cowled engines in the experimental world.

Best of luck to ya!

John

disclaimer...these are all just my stupid opinions.

- The Matronics RV8-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV8-List

_________________
Life is too short to run lean of peak.

walter(at)tondu.com
Guest

Posted: Sun Jan 29, 2006 6:12 pm Post subject: Fwd: plenum

On 01/29  6:32, Nuisance wrote:



 > I did read that article back in '01, and that, together with a strong recommendation from Ken Tunnel at Lycon, is why I ordered my engine with the LASAR system.

 > 

 > The information I tried to get from Harry Fenton when he was still working for Unison was basically a timing map. That is, at what MAP and RPM does the advance start, and what is it at a normal cruise setting, and what is it at a high altitude cruise, etc. This information has always been withheld. We are given the range 0-42 degrees...I think Lightspeed says 0-40. But, it is the essence of this dicussion to consider when, and how much, advance is provided at various settings. This is what I am referring to when I say that the LASAR advance curve is too aggressive...too much advance comes in too early as MAP is reduced, and that is what causes the CHTs to run higher than they should. 

 > 

 > I firmly believe that with LASAR, by the time you provide enough extra cooling air to keep your engine at normal, sub 400 degree CHTs, you have caused enough extra drag to negate the benefit of any extra power you may be getting from the timing advance. You are also putting more strain on the rod and main bearings (see the discussion of thetaPP on the GAMI website, and John Deacon's articles on AVWEB).

 > 

 > I have read (somewhere, maybe on one of these email lists) that the E-mag people are using a more conservative timing advance curve, and I would leap to the conclusion that they are aware of these problems.

 > 

 > LASAR, as a certified system, is stuck with what they have. The company won't put more R&D into the system due to the poor market acceptance on the existing system...they won't even develop a system for Continentals. They did their testing on C-172s and various Pipers that provide huge masses of air for cooling (and go slow). They pushed the timing curve in the attempt to provide more attractive performance results, and didn't realize what would happen to the tighter cowled engines in the experimental world.

 



I agree on every point.  Well said.



-- 

Walter Tondu

http://www.rv7-a.com

Flying!

- The Matronics RV8-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV8-List

Display posts from previous:

	Matronics Email Lists Forum Index -> RV8-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum