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max EGT

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lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Sat Oct 14, 2006 1:10 pm Post subject: max EGT

I looked in my manual for the max egt and it says 1200. This  is the first time that I have had an instrument to check my EGT's on both  cylinders, and my front cylinder runs about 1180 but the back one is hitting 12  40 to 1258 occasionally. I have run it for at least 258 hours without knowing  what the back cylinder is reading. The full throttle has been adjusted to lower  the EGT, but I am on the bottom groove of my needle jet, and cannot go any  richer for the midrange. Does anybody have a differing max reading? I am sure  that a bit of a safety factor has been built in to that high end of the range. I  should add that I have switched to my silencer again and am running a 152 main  jet, and seem to affect the midrange some with the differing main jets. I have  probably ran this setup for some around 125 hours without killing in the motor  so far, but ignorance is bliss. I can of course bring it within range by using  the enrichner circuit. 

     

 I switched back to my silencer because I flew yesterday for 1  hour 3 minutes and burned about 5 gallons of fuel. It is not blubbering it out  of the carb, There is no visible or discernable reason why a 447 is burning that  much fuel. I therefore switched back to the silencer to see if I still burn that  much fuel and to cut down a bit on the noise. With the warp and the fact that it  is closer to the wing it is making a heck of a racket and I have to wear ear  plugs along with my DRE 6000. There is no discernable loss of power, so I  think I will keep it on, but the egt's now that I know about them is concerning  me.

 Opinions would be appreciated.

 Larry, Oregon

    [quote][b]

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sat Oct 14, 2006 1:28 pm Post subject: max EGT

There is no discernable loss of power, so I think I will keep it on, 

but the egt's now that I know about them is concerning me.

Opinions would be appreciated.

Larry, Oregon



Hi Larry:



Pull a little more pitch in the prop and the egt's will come down full 

throttle and probably mid-range as well.  I am not current in 

tinkering with two strokes, been 16 years, but I believe it will also 

pull down egt in mid-range.



Usually, pitching to achieve the redline for max continuous rpm, 6,500 

for the rotax two strokes, will put the egt right in the ball park 

down near sea level.  At your altitude would probably be the same if 

the carb is tuned as it was when it left the factory.



Remember, our engine instruments are not precision.  Don't know if the 

EIS is temperature compensating or not.



Noise.  All Kolbs are noisy, no matter two or four stroke.  Most of 

the noise is generated by the close proximity of the prop blade to the 

trailing edge of the wing, plus all the disturbed air it is trying to 

live in that is generated by the engine and its components.



I never did care for intake silencers or additional exhaust silencers 

on two strokes.  Anything that reduces perfermance seems not to agree 

with me and my flying machines.



You can probably decrease prop noise by going to a prop extension, 

getting the blades away from the trailing edge.



For what it is worth.



john h

mkIII



PS:  Many folks get wrapped around the axle trying to get their two 

stroke or four stroke to operate in the correct range.  The instrument 

sending units are probably not nearly as precise as the engines you 

are flying.  Any way, would rather err on the rich rather than the 

lean side.

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Sat Oct 14, 2006 1:29 pm Post subject: max EGT

What rpm's are you running? Max? Cruise? Climbout?

  

 Richard Pike

 MKIII N420P (420ldPoops)

  

 [quote]   ---

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Sat Oct 14, 2006 2:15 pm Post subject: max EGT

[quote] ---

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sat Oct 14, 2006 4:27 pm Post subject: max EGT

my front cylinder runs about 1180 but the back one is hitting 12 40 

to 1258 occasionally.



Larry, Oregon



Larry:



Understand the heat spike is at 44oo to 4500 rpm.  However, you did 

not say what it was at WOT and your cruise rpm which is 6000.



After a little more thought and the info you posted in response to 

Richard Pike's questions,  I wouldn't get too bent out of shape about 

it.  If it bothers you, then increase or decrease throttle a little to 

find more desireable egt.



Again, pullin a tad more pitch will also reduce egt.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Denny Rowe

Joined: 10 Jan 2006
Posts: 89
Location: Leechburg, PA

Posted: Sat Oct 14, 2006 5:36 pm Post subject: max EGT

 	  Quote: 	
		   Again, pullin a tad more pitch will also reduce egt.



 john h

 mkIII




	




I agree with John, 6600 rpm is a little high for WOT level flight, crank in 

a tad more pitch and get it down around 6400- 6500 and I'll bet you'll like 

the effect on your EGTs across the board.



Denny Rowe

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Sat Oct 14, 2006 6:36 pm Post subject: max EGT

No wonder you are burning so much fuel if you cruise at 6,000. I have my  582 prop pitched so that I climb out at 6,250, max RPM is 6,450, and cruise at  5,300 solo, 5,600 with a passenger, and it uses under 4 gph solo, a little  over 4 gph with a passenger. And it is a whole lot quieter at 5,500 than it is  at 6,000. Crank some pitch into that prop and see if you don't like it a lot  better.

  

 Richard Pike

 MKIII N420P (420ldPoops)

 [quote]   ---

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sat Oct 14, 2006 7:19 pm Post subject: max EGT

cruise at 5,300 solo, 5,600 with a passenger, and it uses under 4 gph 

solo, a little over 4 gph with a passenger. And it is a whole lot 

quieter at 5,500 than it is at 6,000.

Richard Pike



Richard:



5300 solo?



That ain't cruising, that's crawling.  



What is the true airspeed at 5,300 rpm?



My normal cruise with Rotax two strokes was 5,800 rpm, 75% power. 

Fuel burn was 3.75 gph in the 447 and 5 to 5.5 gph with the 582.  Come 

to think of it, I also cruised the Cuyuna at 5,800.  Can't remember 

what it burned, but probably something like 3 to 3.5 gph.



BTW:  Isn't 5,300 rpm just a knotch below where the engine comes up on 

the pipe?  or am I living in the past again?  Maybe all that has 

changed since my two stroke days.  After all, my last one met its 

demise 13 years ago.



Take care,



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Sun Oct 15, 2006 7:14 am Post subject: max EGT

Ah, Dear Brother John - Life has changed since Jurassaic Park...

Pipe? Comes up on the pipe?

What are these strange words that you speak?

<grin>

<can't resist>

<the coffee tastes better while smiling>

When I had my old 532 on the MKIII, getting on and off the pipe was like 

climbing on, or falling off of a ladder, but with this 582 I have now (maybe 

because it has both the intake and exhaust silencers?) there is no 

discernable pipe effect. None. And although I would agree with your earlier 

post that installing intake and exhaust silencers ought to reduce the power 

some (if you have to go to smaller jets when you put the intake silencer on, 

then it ought to be making less power) I still got the same RPM at the same 

prop pitch after I installed it. Don't know why, but I did. No explanation.



With the airframe mods I have made on the MKIII, 5,300 rpm gives me 65 mph 

average. Some days better, some days worse.



If I were a cross country enthusiast like yourself, that would be crawling. 

But since 95% of my flying is to local airports within 50 miles, who cares 

if it is 65 mph or 85 mph? So I save 5 minutes? Big deal. I fly to fly, not 

get there. Besides, the ride is SO much smoother at 65, and the engine is SO 

much quieter at 5,300.



Also, I have a hidden agenda. Since everything else is working perfectly 

satisfactory at that slower RPM, I intend to expand the envelope on the 582 

overhaul time. Since most of the crank bearing wear is due to centrifugal 

loads rather than thrust loads, I plan to operate the 582 to 400 hours 

before overhaul. Running an engine at 5,300 rpm constant rather than 5,800 

rpm constant reduces centrifugal bearing loads enormously.



Unfortunately, since I have had health issues the last two years and am only 

getting in about 50 hours a year, I will have to wait another 5 years to 

find out if this plan has worked or not...



Blessings,

Richard Pike

MKIII N420P (420ldPoops)



---

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Sun Oct 15, 2006 7:33 am Post subject: max EGT

---

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Sun Oct 15, 2006 6:55 pm Post subject: max EGT

Do you have a 2 blade prop or a three blade? A 2 blade is more efficient at 

lower rpm's than a 3 blade. A 3 blade prop has a narrower usable rpm band 

than a 2 blade prop. Back when I was using a 3 blade prop, 5600 was the 

lowest rpm I could fly too. Now I can go to 4800 if I need to and still 

maintain altitude.



Richard Pike

MKIII N420P (420ldPoops)

---

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Sun Oct 15, 2006 7:28 pm Post subject: max EGT

---

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Mon Oct 16, 2006 6:11 am Post subject: max EGT

I think that would be why your fuel burn was so high and the performance was 

so weak. IMO, a 68" three blade on a 582 is way too much prop for good 

efficiency. To get the engine to run right, you have to take a lot of pitch 

out of the blades, and you end up with a climb prop (in effect) even though 

it is in flight adjustable. I am using a 2 blade 68" Ivo, so imagine how 

much more pitch I am running compared to your 3 blade 68" at an equivilent 

rpm. If you had used your in flight adjust to try and add enough pitch to 

get it to cruise well, then surely you would be using 5 gallons per hour, 

because your prop load at an equal pitch to what I am using would be 33% 

higher.



Richard Pike

MKIII N420P (420ldPoops)



---

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

Eugene Zimmerman

Joined: 10 Jan 2006
Posts: 392

Posted: Mon Oct 16, 2006 8:46 am Post subject: max EGT

I agree with Richard.



The  advise of Reverend Pike could enhance the efficiency of your  

cruise ,,,,,,,,,,,,,, as well as the enjoyment of your destination. <g>



On Oct 16, 2006, at 10:09 AM, Richard Pike wrote:



[quote] 



 I think that would be why your fuel burn was so high and the  

 performance was so weak. IMO, a 68" three blade on a 582 is way too  

 much prop for good efficiency. To get the engine to run right, you  

 have to take a lot of pitch out of the blades, and you end up with  

 a climb prop (in effect) even though it is in flight adjustable. I  

 am using a 2 blade 68" Ivo, so imagine how much more pitch I am  

 running compared to your 3 blade 68" at an equivilent rpm. If you  

 had used your in flight adjust to try and add enough pitch to get  

 it to cruise well, then surely you would be using 5 gallons per  

 hour, because your prop load at an equal pitch to what I am using  

 would be 33% higher.



 Richard Pike

 MKIII N420P (420ldPoops)



 ---

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Thu Oct 26, 2006 11:03 am Post subject: Max EGT

Hi,

    Just a follow up on this thread. A lot of you  contributed ideas as to my problem. The main thing was that the only change was  the prop, so it figures that is where the difference came in.

   I have been trying to get the wiring mess under control  so that I can move forward on my certificate and have had a lot of company  so betweens the two haven't been a big mover lately.

    I also had some concern as to the two tanks not  drawing the same. ( back tank higher when flying, so it appears to draw more) I  changed the EIS aux pick up to the rear tank, and that fixed the  problem.

    I also had some concern as to my fuel burn. ( it  was upwards of 4 or more gallons an hour) To fix that I put my "silencer" back  on and put a 148 main jet back in the carb.

    That caused me to have some EGT temps over  1250 on midrange. To fix that I turned in another degree of pitch to the  prop.

  

    I just got back from a flight that was 1 hour and  35 minutes, two takeoffs, three climbs to 1000 feet AGL. ( I had to  check some ponds for ducks for Jessie.) I burned 4 gallons of fuel. My WOT was  6250, I cruised at 56 to 5700 with an average speed of about 63 MPH. I did have  a bit of higher egt temps on one of my landings when I got in the 4000 RPM  range, but I just throttled back more and they dropped. Didn't seem to need that  much power any way.  The OAT was in the 20's when I took  off.

    I am at a bit of a loss as to why I cannot wind  the engine up to 6500 and keep my temps in range as they were with the same carb  set up but a IVO prop. However when I talked to Daryl at Warp he hinted that  things would be a bit different due to the difference in the prop  design.

  

 Thanks for the help

 Larry  

    [quote][b]

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