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rotax 447 propeller recomendation high temps

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tombaisley

Joined: 20 Jan 2012
Posts: 30
Location: afton,ny

Posted: Thu Jun 21, 2012 3:26 am Post subject: rotax 447 propeller recomendation high temps

I have a FS1 w/ 447 2.58 box,  spinning a 66" two blade IVO. I am have trouble with high EGT and CHT. 



   With the propeller pitched to give me 6200rpm at climb out ,I'm seeing EGT in the 1100-1150 at 5700rpm which seems to cause the CHT to start climbing thru 400F.  If I increase the prop pitch to 6000 rpm at climb out my EGT are stable at 1050 or so, but I'm still seeing CHT of 390-410F.

    I also have high EGT ( 1150 - 1230 ) in the 3900-4600rpm range, I suspect that may just be the nature of the beast.

    I spoke with IVO prop and his recommendation was "more pitch", But that seems to aggravate the CHT.



    I'm starting to wonder if I'm over propped and should maybe cut down the diameter or go to a three blade prop?

Richard Pike

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

Posted: Thu Jun 21, 2012 5:05 am Post subject: Re: rotax 447 propeller recomendation high temps

You are running stock jets and have pressure/vacuum tested your engine I assume? Do you have an intake silencer? Because it will cause you to lose a hair of power, and IMO you can't afford to lose any power, because you already have too much prop. 



Back in the day when I had a 532 on the MKIII,  IVO started me out with a 3 blade 64" - that was way too much prop for that engine, took one blade off and it was a sweetheart. Then I put a 2 blade 66" on it and that was good too. If I remember correctly (HAH) my buddies ran 3 blade 62" Warp Drives on their 503's. I am running a 68" 2 blade IVO on my 582, and you are trying to run almost as much prop on a much smaller engine, so I would say you are way overloaded on prop.



This might be comparing apples to oranges, but at the Powerfin prop selection page http://www.powerfin.com/eng_Rotax.htm  they show either a 2 blade 61" or a 2 blade 64" prop for your engine. 



If I were you - before I spent any money on another prop, I would start by shortening your current blades a bit at a time and see what happens. I suspect that when you get down around 62"  - 64" you will find things to be OK assuming that all else with your engine is as it should be.

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

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

Last edited by Richard Pike on Thu Jun 21, 2012 5:40 am; edited 1 time in total

John Hauck

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

Posted: Thu Jun 21, 2012 5:27 am Post subject: rotax 447 propeller recomendation high temps

---- tombaisley <tombaisley(at)yahoo.com> wrote: 

 

 	  Quote: 	
		       I'm starting to wonder if I'm over propped and should maybe cut down the diameter or go to a three blade prop?

 
	


Tom B/Folks:



I prop a Kolb by flying straight and level, wide open throttle.  A correctly propped engine should turn the max continuous red line.  This will give best cruise and climb performance with a fixed or ground adjustable prop.



I flew a 60X30 Culver two blade fixed pitch prop on my original Firestar and 447.  This gave me 6500 rpm straight and level, WOT.



john h

mkIII

Burns Junction, OR

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

beauford

Joined: 25 Apr 2007
Posts: 127
Location: Brandon, FL

Posted: Thu Jun 21, 2012 5:50 am Post subject: rotax 447 propeller recomendation high temps

I have a FS1 w/ 447 2.58 box,  spinning a 66" two blade IVO. I am have

trouble with high EGT and CHT. 



  I suspect that may just be the nature of the beast.



    -------------------------

Brother Baisley:



I run exactly the same 447/gearbox/prop combination as you, sir...

My prop is loaded to yield exactly the same rpm on climb out as yours...

My EGT/CHT temps mirror yours exactly.... 



I have, after much carburetor twiddling, fan fumbling, prop pitch changes, a

thermocouple replacement festival,

and several sessions of peering and poking at rings through exhaust ports,

finally come to the

conclusion that the little Nazi S.O.B. just likes to run hot.   I don't

know, but strongly suspect, that

performing a carbon-fiber circumcision on your IVO won't solve the problem;

that is just

another way to reduce prop loading and the effects of that upon the EGT/CHT

balance is already

known and understood.  Am pretty sure there is no free thermal lunch hiding

in there anywhere.



I place the issue of chronic 447 overheating in the same category of

intractable problems as matrimony,

stagflation and oversize prostates.  They are built into the bedrock of the

universe and we might as

well get used to 'em...



Accordingly, I have perfected and adopted the Beaufordian school of 447

operational philosophy... i.e.

run the chrome-plated hell out of the damn thing and don't worry about it.

It works fer me...   may not

work fer you...   I think of it as rather like Dr. Stangelove's approach...

Quit worrying about the Bomb and

learn to love it.



Worth what ye paid fer it...



Do Not Archive



Overheated beauford

FF-076

Brandon, FL



p.s.  Brother B:  Should you come across the 447 holy grail and figure out

how to make it run cooler,

please write home and share it without delay...

b.

tombaisley

Joined: 20 Jan 2012
Posts: 30
Location: afton,ny

Posted: Thu Jun 21, 2012 5:52 am Post subject: Re: rotax 447 propeller recomendation high temps

I'm running stock jets, needle, and clip position. No intake silencer, stock exhaust. I replaced the head, base, intake, and exhaust gaskets. I had found that the spark plugs were cross threaded and not sealing. I have not pressure tested, but this engine is very fresh <100hours. 

  Travis (at) Kolb recomends 60" three blade IVO, My friend at the field has a FSII w/503 spinning at 62" IVO, runs like a top. I would like to stay with a two blade, I think I will start trimming 1" at a time to see what happens.

Richard Pike

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

Posted: Fri Jun 22, 2012 6:47 am Post subject: Re: rotax 447 propeller recomendation high temps

Called a friend of mine yesterday who has a Flightstar with a 447 on it, and he said the only way he got it to behave and run cool was to install a Dial-A-Jet on it, and run a cable to the cockpit.

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

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

beauford

Joined: 25 Apr 2007
Posts: 127
Location: Brandon, FL

Posted: Fri Jun 22, 2012 7:48 am Post subject: rotax 447 propeller recomendation high temps

---------------------------------------------------




Called a friend of mine yesterday who has a Flightstar with a 447 on it, and

he said the only way he got it to behave and run cool was to install a

Dial-A-Jet on it, and run a cable to the cockpit.



-----------------------------------

Brother Pike:



That is interesting...  Thought those things were just for snowmobiles. 



Do you have any information about how many hours he has run

it and whether he has had any carbon build-up problems with it?



The way I understand the DAJ set-up is that the engine is baseline jetted to

run on the

lean side and the DAJ then dumps extra fuel into the carb as required to

compensate for the lean condition, temperature, altitude, etc.



I know that enriching the mixture will make it run cooler, but I also have

vivid recollections of the carbon problems which stuck the rings on my

toy once before.  Am a little bit carbon-shy, but very interested in what

your friend has done and how long he has been using the gizmo...



Thankee for the reply, sir...



Wary eye on the Gulf  beauford

FF-076

Brandon, FL

John Hauck

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

Posted: Fri Jun 22, 2012 8:00 am Post subject: rotax 447 propeller recomendation high temps

> Called a friend of mine yesterday who has a Flightstar with a 447 on it, and he said the only way he got it to behave and run cool was to install a Dial-A-Jet on it, and run a cable to the cockpit.

 	  Quote: 	
		   

 --------

 Richard Pike

 
	


Kolbers:



I realize this is ancient history, but it is all the personal info I have with the 447, which I put 755.0 hours on two of them from 1987 to 1990 in my original Firestar.



Through experience I learned to leave the engine exactly like it came from the factory.  What worked for me was to adjust the prop pitch so the engine would barely touch the red line for max continuous rpm, which I think was 6,500 rpm.  When I did this the EGT/CHT operated in the Green.



I found it very easy to chase one's tail trying to "tune" a 447.  I believe the 447 was set up at the factory to operate in a 70F day from 0 to 1,500 feet ASL.  



With the engine remaining at factory tune, I was able to climb to 10,000 feet ASL.



john h

mkIII

Rock House, Burns Junction, OR

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

John Hauck

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

Posted: Fri Jun 22, 2012 8:14 am Post subject: rotax 447 propeller recomendation high temps

 	  Quote: 	
		   I know that enriching the mixture will make it run cooler, but I also have

 vivid recollections of the carbon problems which stuck the rings on my

 toy once before.   

 

 Wary eye on the Gulf  beauford

 
	


Kolbers:



I had good luck with the old point ignition, single carb 447, other than the normal operating problems of failed wrist pin bearings (which were later improved), loose coils, and difficulty keeping the points in adjustment caused by normal wear (which were upgraded to CDI ing).



Have always been an advocate of not babying two stroke engines and operating at recommended cruise rpm which is 5,800 rpm, if I remember correctly.  I didn't say abuse two stroke engines, but make them work to keep crank cases clear of excess oil and reduce carbon buildup in the upper end.



I found there are a lot of "little things" that can affect the operation and reliability of a two stroke, many not logical or readily understandable.



Having the opportunity to fly with a 4 stroke since 1994, I have a much better reliablity record.  No engine failures in more than 3,000.0 hours.



john h

mkIII

Burns Junction, OR

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

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Fri Jun 22, 2012 9:14 am Post subject: rotax 447 propeller recomendation high temps

Roger Lee, Rotax guru on their Matronics list has maintained that the biggest problem with Rotax engines is their owners. I've set up a few new 447's now and they run great right out of the box WHEN you set up the prop per Rotax instructions, which as John H said is to just get the prop to touch max RPM in level flight. For the 447 this is 6800 rpm and setting it for about 6400 to 6500 static will get you right there. The only, and I honestly think only two adjustments that need to made to a new 447 are fan belt tension, and, depending on your field elevation, the clip on the needle. Once the break in is accomplished, the fan belt is adjusted and the clip is reset, if needed, they run perfectly. The last one I did was on a Northwing trike. I finished the break in just after sun down and didn't get started to test fly until about 2:00 pm the next day. The temps were already in the high 100's headed for 112 that day, iirc, and the little Maverick trike broke ground in about 200 and I had pattern altitude long before I was abreast of my back yard (2300 feet from the departure end of 17). You have a little leeway in the prop adjustment to find the sweet spot for CHT and EGT. If you CHT's are on the hot side decrease the prop pitch and it should drop a bit. It it's the EGT's that are troublesome, add pitch.

 Pretty much what is in the Installation manual, and it seems to work just fine.

Rick Girard

On Fri, Jun 22, 2012 at 11:13 AM,  <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)> wrote:

  	  Quote: 	
		  --> Kolb-List message posted by: <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)>

 	  Quote: 	
		   I know that enriching the mixture will make it run cooler, but I also have

 > vivid recollections of the carbon problems which stuck the rings on my

 > toy once before.

 >

 	  Quote: 	
		   Wary eye on the Gulf  beauford

Kolbers:

 I had good luck with the old point ignition, single carb 447, other than the normal operating problems of failed wrist pin bearings (which were later improved), loose coils, and difficulty keeping the points in adjustment caused by normal wear (which were upgraded to CDI ing).

 Have always been an advocate of not babying two stroke engines and operating at recommended cruise rpm which is 5,800 rpm, if I remember correctly.  I didn't say abuse two stroke engines, but make them work to keep crank cases clear of excess oil and reduce carbon buildup in the upper end.

 I found there are a lot of "little things" that can affect the operation and reliability of a two stroke, many not logical or readily understandable.

 Having the opportunity to fly with a 4 stroke since 1994, I have a much better reliablity record.  No engine failures in more than 3,000.0 hours.

 john h

 mkIII

 Burns Junction, OR

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 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

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-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

   - Groucho Marx

  [quote][b]

_________________
The smallest miracle right in front of you is enough to make you happy....

herbgh(at)nctc.com
Guest

Posted: Fri Jun 22, 2012 11:49 am Post subject: rotax 447 propeller recomendation high temps

and don't forget to re torque the heads ....after 1 hour...Herb 

 At 12:13 PM 6/22/2012, you wrote:

 [quote]Roger Lee, Rotax guru on their Matronics list has maintained that the biggest problem with Rotax engines is their owners. I've set up a few new 447's now and they run great right out of the box WHEN you set up the prop per Rotax instructions, which as John H said is to just get the prop to touch max RPM in level flight. For the 447 this is 6800 rpm and setting it for about 6400 to 6500 static will get you right there. The only, and I honestly think only two adjustments that need to made to a new 447 are fan belt tension, and, depending on your field elevation, the clip on the needle. Once the break in is accomplished, the fan belt is adjusted and the clip is reset, if needed, they run perfectly. The last one I did was on a Northwing trike. I finished the break in just after sun down and didn't get started to test fly until about 2:00 pm the next day. The temps were already in the high 100's headed for 112 that day, iirc, and the little Maverick trike broke ground in about 200 and I had pattern altitude long before I was abreast of my back yard (2300 feet from the departure end of 17).

 You have a little leeway in the prop adjustment to find the sweet spot for CHT and EGT. If you CHT's are on the hot side decrease the prop pitch and it should drop a bit. It it's the EGT's that are troublesome, add pitch.

 Pretty much what is in the Installation manual, and it seems to work just fine.

 Rick Girard

 On Fri, Jun 22, 2012 at 11:13 AM, <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)> wrote:

   --> Kolb-List message posted by: <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)>

  > I know that enriching the mixture will make it run cooler, but I also have

  > vivid recollections of the carbon problems which stuck the rings on my

  > toy once before.

  >

  > Wary eye on the Gulf  beauford

  Kolbers:

  I had good luck with the old point ignition, single carb 447, other than the normal operating problems of failed wrist pin bearings (which were later improved), loose coils, and difficulty keeping the points in adjustment caused by normal wear (which were upgraded to CDI ing).

  Have always been an advocate of not babying two stroke engines and operating at recommended cruise rpm which is 5,800 rpm, if I remember correctly.  I didn't say abuse two stroke engines, but make them work to keep crank cases clear of excess oil and reduce carbon buildup in the upper end.

  I found there are a lot of "little things" that can affect the operation and reliability of a two stroke, many not logical or readily understandable.

  Having the opportunity to fly with a 4 stroke since 1994, I have a much better reliablity record.  No engine failures in more than 3,000.0 hours.

  john h

  mkIII

  Burns Junction, OR

  ===========

   arget="_blank">http://www.matronics.com/Navigator?Kolb-List

  ===========

   http://forums.matronics.com

  ===========

  le, List Admin.

  ="_blank">http://www.matronics.com/contribution

  ===========

 -- 

 Zulu Delta

 Mk IIIC

 Thanks, Homer GBYM

 It isn't necessary to have relatives in Kansas City in order to be unhappy.

   - Groucho Marx

 [b]

beauford

Joined: 25 Apr 2007
Posts: 127
Location: Brandon, FL

Posted: Fri Jun 22, 2012 12:56 pm Post subject: rotax 447 propeller recomendation high temps

Rick and John:

 

Many thanks for your inputs, Gents…   My 447 has the original factory jetting and needle is currently in second notch…  The IVO turns 6050 static, 6250 in climb and 6550 WOT level…   If I leave it at WOT in climb for more than a minute, the CHT will go to and through redlines. 

 

At 5800 cruise I am seeing 390 to 400 CHT and EGTs of 1080 and 1140 for the two cylinders.  The plugs have a nice tan color, so I think

the jetting is OK.  The crankshaft seals are new, as are the intake and exhaust gaskets…. I do not suspect leaks.

 

Based on Rick’s input, on the first dry day I will unload the prop to get 6400 static and pull the needle up to see if the EGT’s will stay under control.

 

If you never hear from me again, you may assume this did not pan out…   monitor the FL obits…

 

Soggy beauford

FF-076

Brandon, FL

 

P.S.  I agree with guru Roger Lee…   (see below).

 

------------------------------------------------------

 

From: owner-kolb-list-server(at)matronics.com [mailto:owner-kolb-list-server(at)matronics.com] On Behalf Of Richard Girard

Subject: Re: Re: rotax 447 propeller recomendation high temps



 

Roger Lee, Rotax guru on their Matronics list has maintained that the biggest problem with Rotax engines is their owners. I've set up a few new 447's now and they run great right out of the box WHEN you set up the prop per Rotax instructions, which as John H said is to just get the prop to touch max RPM in level flight. For the 447 this is 6800 rpm and setting it for about 6400 to 6500 static will get you right there

Rick Girard

--> Kolb-List message posted by: <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)>



Have always been an advocate of not babying two stroke engines and operating at recommended cruise rpm which is 5,800 rpm, if I remember correctly.  I didn't say abuse two stroke engines, but make them work to keep crank cases clear of excess oil and reduce carbon buildup in the upper end.



john h

mkIII

 	  Quote: 	
		   	


  [quote][b]

Richard Pike

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

Posted: Fri Jun 22, 2012 4:30 pm Post subject: Re: rotax 447 propeller recomendation high temps

My personal experience is that if I set the prop to just bump redline in straight and level, then the EGT  tends to be a bit uncooperative, but that could be the difference between the IVO and the Warp. Probably the Warp and the IVO respond differently. So I set the IVO to fall about 150-200 rpm shy of redline in level flight, and then my EGT stays constant at all rpm's.



Your results may vary, that is why they are called Experimental aircraft...

_________________
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: Fri Jun 22, 2012 5:35 pm Post subject: rotax 447 propeller recomendation high temps

 	  Quote: 	
		   My personal experience is that if I set the prop to just bump redline in straight and level, then the EGT  tends to be a bit uncooperative, but that could be the difference between the IVO and the Warp. Probably the Warp and the IVO respond differently.  

 --------

 Richard Pike

  
	




Richard P/Folks:



Works for me with Culver two blade wooden prop.



Never flew the 447 with any other.



I still prop all my engines the same way, two or four stroke, for best performance for me.



john

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

tombaisley

Joined: 20 Jan 2012
Posts: 30
Location: afton,ny

Posted: Fri Jun 22, 2012 6:09 pm Post subject: Re: rotax 447 propeller recomendation high temps

I have had much success after trimming my prop from 66" to 62". My CHT are under 400f and my EGT are 1060f (at) 5700rpm. For the must part my egt are <1100 with only a hot spot around 4100-4500rpm which I avoid during decent 

 I'm so pleased with the way the engine is running, I'm done fiddling and just flying. All that is left to do is check the plugs in a couple of hours.

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