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Running 582 Engines LOP

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BobP

Joined: 16 Aug 2013
Posts: 10
Location: UK

Posted: Mon Aug 26, 2013 3:37 am Post subject: Running 582 Engines LOP

I have a Rotax 582 with a warp comp prop in a Pulsar. The engine has the oil injection system fitted.



Because of the slippery Pulsar profile  (5000rpm and 90 knots at 12 litres/hour) EGTs tend to nudge the maximum limit  when in fast cruise descent - because of the low load on the fast revving engine. I prefer the keep the engine away from red line limits, and can reduce EGTs by either throttling back even further so the engine is developing minimal power, or by slowing the plane down and applying flaps to make the plane more draggy. 



Neither of these options is ideal, and I wondered if it is possible to safely reduce EGTs (at cruise power) by running the 582 engine  lean of peak (LOP) eg by using a hacman type device to weaken the mixture. The normal cruise mix seems fine (plugs noses mid to deep brown) so I don't want to raise the carb needle and richen this setting.



Any thoughts/experience on running a 582 injected engine LOP appreciated - good and bad.



Thanks



Bob P

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_________________
BobP

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Mon Aug 26, 2013 6:52 am Post subject: Running 582 Engines LOP

On 8/26/2013 4:37 AM, BobP wrote:  	  Quote: 	
		      	  Quote: 	
		  Neither of these options is ideal, and I wondered if it is possible to safely reduce EGTs (at cruise power) by running the 582 engine  lean of peak (LOP) eg by using a hacman type device to weaken the mixture. The normal cruise mix seems fine (plugs noses mid to deep brown) so I don't want to raise the carb needle and richen this setting.

  	
 	
     Well. As far as I know there's no such thing as LOP for a 582. Or if there is, the peak is well beyond what the engine will handle. So you always live rich of peak, but constantly bump up against it, since the EGT limit gives you best power and fuel economy. (That said, I have run too lean by long descent with a lean mixture through "peak" until the engine quit. The engine was at idle, however, so I never noticed an EGT "peak".)

     Your idea of using a Hacman for EGT control is a good one, though. I used one all the time I had my 582 (4 years, 500 hours) and loved it. I only had to change mains a couple of times, in Utah and Idaho, when I was spending a lot of time at altitude and wanted to "re-center" my mixture control. (My home port was at 1500'.) The Hacman gave me about 80F EGT range, which seems small, but is quite useful. What Hacman will not do is give you enough control to go downhill any way you want. If your mains are set correctly you'll always be able to redline the EGT going down hill. You just have to get used to either very long or very short or stepped descents. (There was another system on the market which screwed the mid-range needles in and out that might have given more control. Don't know what happened to it.) I highly recommend the Hacman. (Easy to install, too.)

 

 Guy Buchanan

 Ramona, CA

 Kitfox IV-1200 / 912-S / Warp 3cs / 500 hrs. and grounded

 Now a glider pilot, too.

 

 

    [quote][b]

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_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

jconnell(at)fmwildblue.co
Guest

Posted: Tue Aug 27, 2013 9:32 am Post subject: Running 582 Engines LOP

Iâ€™ve been doing a bit of reflecting about running Lean of Peak (LOP) on  Rotax 2-cycle engines.

  

 Four-cycle engines have have an oil pump to distribute oil for  lubrication.  In the two-cycle engine, it is the air/oil mixture that  provides the cylinder-to-piston lubrication.  It would seem somewhat risky  to get excessively lean as this might lead to seized pistons.  Can someone  qualify this issue a little more fully for me?

  

 Thanks...

  

 Joe Connell

  

 

Subject: Running 582 Engines LOP

From: "BobP"  <matronics(at)panth.co.uk (matronics(at)panth.co.uk)>

I  have a Rotax 582 with a warp comp prop in a Pulsar. The engine has the oil  injection

system fitted.



Because of the slippery Pulsar profile   (5000rpm and 90 knots at 12 litres/hour)

EGTs tend to nudge the maximum  limit  when in fast cruise descent - because

of the low load on the fast  revving engine. I prefer the keep the engine away

from red line limits, and  can reduce EGTs by either throttling back even further

so the engine is  developing minimal power, or by slowing the plane down and

applying flaps to  make the plane more draggy. 



Neither of these options is ideal, and I  wondered if it is possible to safely reduce

EGTs (at cruise power) by running  the 582 engine  lean of peak (LOP) eg

by using a hacman type device to  weaken the mixture. The normal cruise mix seems

fine (plugs noses mid to deep  brown) so I don't want to raise the carb needle

and richen this  setting.



Any thoughts/experience on running a 582 injected engine LOP  appreciated - good

and bad.



Thanks



Bob  P



--------

BobP



   [quote][b]

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Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Tue Aug 27, 2013 10:42 am Post subject: Running 582 Engines LOP

In a 2-cycle there's no cooling cycle and no oil bath on the back side 

of the piston so max EGT's are much lower. (1250F versus 1600F) If you 

seriously exceed the EGT limit on a 2-cycle you generally melt a hole in 

the top of the piston which reduces your compression somewhat.



Guy Buchanan

Ramona, CA

Kitfox IV-1200 / 912-S / Warp 3cs / 500 hrs. and grounded

Now a glider pilot, too.



On 8/27/2013 10:28 AM, Joe & Jan Connell wrote:

 	  Quote: 	
		   Four-cycle engines have have an oil pump to distribute oil for 

 lubrication.  In the two-cycle engine, it is the air/oil mixture that 

 provides the cylinder-to-piston lubrication.  It would seem somewhat 

 risky to get excessively lean as this might lead to seized pistons.  

 Can someone qualify this issue a little more fully for me?

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_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

gfmjr_20(at)hotmail.com
Guest

Posted: Tue Aug 27, 2013 1:23 pm Post subject: Running 582 Engines LOP

 

Just wanted to check with the group before I begin my carb rebuilds.  I have a 912uls on a Zodiac 601XLB that has started to be hard starting , in fact it will not start now unless I spray starting fluid into the air intake.  Only did it once to convince myself it was a fuel issue. the engine started  and would restart after an hour. However, if I leave the plane for a week or so it will not start. The engine acts like it is not getting fuel.  I've pulled the carb bowls and all looks fine. Fuel in bowl and  fuel is about  1/2 inch from top.   Engine has 450 hours without a carb rebuild.  Any other ideas what it could be? All input appreciated

 

Thanks

George

 		 	   		  

  [quote][b]

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