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447 tuning tips

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2danglico

Joined: 08 Sep 2008
Posts: 17
Location: Seneca SC

Posted: Thu Sep 18, 2008 4:22 am Post subject: 447 tuning tips

Hi guys,

I've got rid of the surging and stumbling at part throttle I was having. Adjusting the jet needle down one groove did the trick. It even brought my EGT more in line 900-1000. However my CHT's remained unchanged and are still showing below 300. The front one is closer to 250. This has me a little concerned but the engine seems to be running smooth and the plugs don't indicate a rich condition. I was wondering if dropping a size down on the main jet would be a good idea? Also I can only manage 6100 rpm at WOT. Is this just the prop pitch that dictates max engine speed or am I not making full power? Thanks for any advice. John Tempest

aslsa.rng(at)gmail.com
Guest

Posted: Thu Sep 18, 2008 4:37 am Post subject: 447 tuning tips

John, Where are you getting the WOT reading, on the ground or in the air?



Rick



On Thu, Sep 18, 2008 at 7:22 AM, 2danglico <john.tempest(at)basf.com (john.tempest(at)basf.com)> wrote:

 [quote]--> Kolb-List message posted by: "2danglico" <john.tempest(at)basf.com (john.tempest(at)basf.com)>

  

 Hi guys,

 I've got rid of the surging and stumbling at part throttle I was having. Adjusting the jet needle down one groove did the trick. It even brought my EGT more in line 900-1000. However my CHT's remained unchanged and are still showing below 300. The front one is closer to 250. This has me a little concerned but the engine seems to be running smooth and the plugs don't indicate a rich condition. I was wondering if dropping a size down on the main jet would be a good idea? Also I can only manage 6100 rpm at WOT. Is this just the prop pitch that dictates max engine speed or am I not making full power? Thanks for any advice. John Tempest

  

 

 

 

 Read this topic online here:

 

 [url=http://forums.matronics.com/viewtopic.php?p 4898#204898]http://forums.matronics.com/viewtopic.php?p 4898#204898[/url]

 

 

 

 

 

 

 

 

 

 

 [b]

gaman(at)att.net
Guest

Posted: Thu Sep 18, 2008 1:12 pm Post subject: 447 tuning tips

Head temps reflect load more than anything else.Put your pitch where you want it ,for climb or cruise and adjust the needle to get the mixture/exhaust temps where you want them for the cruising speed/rpm at which  you operate your engine.

---

2danglico

Joined: 08 Sep 2008
Posts: 17
Location: Seneca SC

Posted: Thu Sep 18, 2008 1:34 pm Post subject: Re: 447 tuning tips

Rick,

  That's in the air. I've a wood prop so I can't adjust the pitch. -John

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Thu Sep 18, 2008 1:56 pm Post subject: Re: 447 tuning tips

If the engine runs correctly, and the plugs are the correct color, and the temperatures are where they should be then I would fly it.  On the Trike that I fly we have the prop adjusted so that we get around 6100 RPM full power climbout maximum.  Turning the prop faster just runs the piss out of the engine, makes the temperatures much harder to keep in limits, and only gives a very small amount more power, hardly enough to make a difference on the Trike.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

aslsa.rng(at)gmail.com
Guest

Posted: Thu Sep 18, 2008 7:35 pm Post subject: 447 tuning tips

With all deference to the ideas of Mr. Aman, they are contrary to what Rotax recommends. Your prop is over pitched and you can chase jetting until the cows come home, it'll never come right until the prop is right for the engine. >From Rotax Service Information document 3UL-89E (available from R.O.A.N.)

Attention:

If you wish to run your aircraft for noise reasons or other intentions constantly at

reduced engine r.p.m. (limited throttle lever command or carburetor slide opening),

 you neverthelee have to chose the propeller by testing at the full throttle r.p.m. (fully

open carburetor).

From Rotax Installation Manual pg 21-1

"....properly loaded with matched propeller for Max RPM (emphasis mine)

 



The RPM you are getting is about right for climb out or max RPM when sitting still on the ground, but it is low for WOT. Do you have a friend with a prop you could borrow to test?



 



Rick



On Thu, Sep 18, 2008 at 4:34 PM, 2danglico <john.tempest(at)basf.com (john.tempest(at)basf.com)> wrote:

[quote]  --> Kolb-List message posted by: "2danglico" <john.tempest(at)basf.com (john.tempest(at)basf.com)>

 

 Rick,

   That's in the air. I've a wood prop so I can't adjust the pitch. -John

 

 

 

 

 Read this topic online here:

 

 [url=http://forums.matronics.com/viewtopic.php?p 4983#204983]http://forums.matronics.com/viewtopic.php?p 4983#204983[/url]

 

 

 

 

 

 

 

 

 

 

 [b]

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Fri Sep 19, 2008 7:37 am Post subject: Re: 447 tuning tips

I read your quotes from the Rotax manual, but I do not see where it says anything about that your prop MUST turn the full 6800 RPM.   I think you are misinterpreting what you are reading.   Many props on the 447 do not turn 6800 RPM, that is quite normal.  There is no requirement to turn the full 6800 RPM, and the temperatures that John was quoting were pretty good.   The best indicator, which is the color of the plugs, is fine, I would not go chasing a problem that does not exist.  Both the trike I fly, and my friends trike both with  447 both turn about 6100 RPM maximum to get the best temperatures without running the piss out of and abusing the engine.  They both run very well with in limit temps.  Don't get the idea that you must run an engine at absolute maximum RPM...



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

aslsa.rng(at)gmail.com
Guest

Posted: Sun Sep 21, 2008 3:51 am Post subject: 447 tuning tips

Mike, John, all, I regret leaving out HP when I said the engine must reach full RPM. Look at the graphs in the operators manual and you see that the engine develops its peak HP at 6500 RPM and this is what must be achieved at WOT, not 6800 RPM as Mike interpreted my remarks.  This is also reflected in SI 3UL - 89E. The graphs here are directed at various problems that occur when the prop is not matched to the engine so that it reaches "nominal RPM" at WOT.Back to the graphs in the Operation Manual. John says he is getting 6100 RPM WOT in level flight. I would guess he is seeing 5700 to 5800  RPM in climb. This represents an 8 to 10 per cent loss of horsepower. Why on earth would you want to tune for that? Sort of like running the engine with one arm tied behind its back :-}

 John, I've never had dealings with Ronnie Smith at South Mississippi Light Aircraft but he comes highly recommended by John H and others here on the list. Give him a call and describe your symptoms. I'll bet you a quarter he'll tell you your prop pitch is too steep.

 



Rick

  [quote][b]

gaman(at)att.net
Guest

Posted: Sun Sep 28, 2008 5:47 pm Post subject: 447 tuning tips

Sorry Richard,

       Thought we were talking about a adjustable prop.I set my IVO for 6200rpm climb out (at)WOT which gave my FS  65mph indicated (at) 5500-5700 rpm cruise.Then jetted it for 1100 degrees(at) cruise power setting.The first 120 hrs it ran on 100LL.It was oil injected.At 25 hrs on the plugs, light tan with large white lead bloom on the ground tip.Head temps were seldom above 300 degrees, only on long steep climbs.When I switched to 87 no lead ,nothing changed except the EGT's.They ran 50 degrees higher on no lead. so I moved the clip up 1 groove on the needles.I use both fuels on long cross country flights and had on problems with this for the 600+ hours I put on that 503 before it was sold. I can't tell you what kind of manifold pressure I put on  that engine,but it required less than an inch of cable to be pulled out of the housing at cruise.My opologies to the Rotax manual.

---

aslsa.rng(at)gmail.com
Guest

Posted: Sun Sep 28, 2008 6:34 pm Post subject: 447 tuning tips

Gary, Why apologize for doing exactly what Rotax recommends? This is exactly what needs to be done in exactly the right order of doing it. Perhaps we were just talking to the same starting point from a different ending. In the case of the engine under consideration, the prop is over pitched and only gets 5800 RPM at WOT on climb out. Until it's set up as yours is, adjusting the jetting will be a wild goose chase at best.  



Rick



On Sun, Sep 28, 2008 at 8:47 PM, gary aman <gaman(at)att.net (gaman(at)att.net)> wrote:

[quote] Sorry Richard,

       Thought we were talking about a adjustable prop.I set my IVO for 6200rpm climb out (at)WOT which gave my FS  65mph indicated (at) 5500-5700 rpm cruise.Then jetted it for 1100 degrees(at) cruise power setting.The first 120 hrs it ran on 100LL.It was oil injected.At 25 hrs on the plugs, light tan with large white lead bloom on the ground tip.Head temps were seldom above 300 degrees, only on long steep climbs.When I switched to 87 no lead ,nothing changed except the EGT's.They ran 50 degrees higher on no lead. so I moved the clip up 1 groove on the needles.I use both fuels on long cross country flights and had on problems with this for the 600+ hours I put on that 503 before it was sold. I can't tell you what kind of manifold pressure I put on  that engine,but it required less than an inch of cable to be pulled out of the housing at cruise.My opologies to the Rotax manual.

 ---

aslsa.rng(at)gmail.com
Guest

Posted: Sun Sep 28, 2008 6:41 pm Post subject: 447 tuning tips

Gary, Darn it, hit the send button too early. The other problem with having low WOT RPM is the horsepower loss. The top of the 447's power curve is pretty flat from 6200 to 6600 RPM. At 5800 the engine is down 7 to 10%. That's a pretty good reason for getting the prop set up right, too. 



Rick



On Sun, Sep 28, 2008 at 9:33 PM, Richard Girard <aslsa.rng(at)gmail.com (aslsa.rng(at)gmail.com)> wrote:

[quote] Gary, Why apologize for doing exactly what Rotax recommends? This is exactly what needs to be done in exactly the right order of doing it. Perhaps we were just talking to the same starting point from a different ending. In the case of the engine under consideration, the prop is over pitched and only gets 5800 RPM at WOT on climb out. Until it's set up as yours is, adjusting the jetting will be a wild goose chase at best.   



Rick

On Sun, Sep 28, 2008 at 8:47 PM, gary aman <gaman(at)att.net (gaman(at)att.net)> wrote:

 [quote] Sorry Richard,

       Thought we were talking about a adjustable prop.I set my IVO for 6200rpm climb out (at)WOT which gave my FS  65mph indicated (at) 5500-5700 rpm cruise.Then jetted it for 1100 degrees(at) cruise power setting.The first 120 hrs it ran on 100LL.It was oil injected.At 25 hrs on the plugs, light tan with large white lead bloom on the ground tip.Head temps were seldom above 300 degrees, only on long steep climbs.When I switched to 87 no lead ,nothing changed except the EGT's.They ran 50 degrees higher on no lead. so I moved the clip up 1 groove on the needles.I use both fuels on long cross country flights and had on problems with this for the 600+ hours I put on that 503 before it was sold. I can't tell you what kind of manifold pressure I put on  that engine,but it required less than an inch of cable to be pulled out of the housing at cruise.My opologies to the Rotax manual.

  ---

jbhart(at)onlyinternet.ne
Guest

Posted: Mon Sep 29, 2008 4:26 am Post subject: 447 tuning tips

At 02:34 PM 9/18/08 -0700, you wrote:

 	  Quote: 	
		  



Rick,

  That's in the air. I've a wood prop so I can't adjust the pitch. -John




	


John,



If you are over propped, you still have the option of removing some material 

from the propeller tips to get engine speed up.  If you do this, make a 

locating bracket so that you are sure you take the same amount off each tip, 

and then check for balance. 



Jack B. Hart FF004

Winchester, IN

2danglico

Joined: 08 Sep 2008
Posts: 17
Location: Seneca SC

Posted: Wed Oct 01, 2008 6:49 am Post subject: Re: 447 tuning tips

Thanks for the good tips guys. I recently got in touch with the new owners of Culver props, and they are going to sand my prop down, taking it from 30 to 29 degrees, balance and varnish. All for 75 clams. I'm hoping it'll give me a few hundred RPM more, and maybe bring up my CHT without sacrificing too much cruise speed that I've been enjoying with my overdrive prop. -John

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